study of factors influencing the quality and yield of biodiesel

study of factors influencing the quality and yield of biodiesel
FACULTY OF ENGINEERING AND SUSTAINABLE DEVELOPMENT
STUDY OF FACTORS INFLUENCING THE QUALITY AND
YIELD OF BIODIESEL PRODUCED BY
TRANSESTERIFICATION OF VEGETABLE OILS
Zaloa Ares Gondra
June 2010
Master’s Thesis in Energy Systems
Master’s Programme in Energy Systems
Examiner: Jan Akander
Supervisor: Peter Norberg
PREFACE
This paper is a final thesis for the Energy Systems Master Programme in the University of
Gävle. It was carried out from March to June 2010 in the Faculty of Engineering and
Sustainable Development which belongs to the university. This thesis could not have been
completed without the help and support of many people, some of them are mentioned
below.
First of all, I would like to thank Peter Norberg, the supervisor of this thesis. His willingness
to help me and his interest concerning the project were essential for the success of it. I
really appreciate the time he devoted to it, as well as all his attention and support. He
certainly is a great source of knowledge about many different topics and this was very
valuable for me.
I would also like to thank all the people working in the Faculty of Engineering and
Sustainable Development, for providing their help when I needed it and for making my stay
comfortable.
Furthermore, I would like to express my gratitude to The Dallas Group of America for the
delivery of different products needed for the completion of the thesis.
I should also mention my friends here in Gävle for their support and for sharing many great
times with me.
Finally, I would like to thank my family, particularly my parents, because, without their help,
none of this would have been possible.
No one mentioned, no one forgotten.
Gävle, June 2010
Zaloa Ares Gondra
ABSTRACT
Biofuels are a developing kind of fuel whose origin is biomass. Among them, many
different kind of fuels can be found: bioethanol, biobutanol, biodiesel, vegetable oils,
biomethanol, pyrolysis oils, biogas, and biohydrogen. This thesis work is focused on the
production of biodiesel, which can be used in diesel engines as a substitute for mineral
diesel. Biodiesel is obtained from different kinds of oils, both from vegetable and animal
sources. However, vegetable oils are preferred because they tend to be liquid at room
temperature.
The process to obtain biodiesel implies first a reaction between the oil and an alcohol,
using a catalyst and then a sedimentation, where the biodiesel and the glycerol, the two
products that are obtained, can be separated because of their difference in density. After
the separation, raw biodiesel is obtained and a treatment with either water bubbling or dry
cleaning products is needed to obtain the product which will be ready to use.
Many methods are available for the production of biodiesel, most of them require heat for
the transesterification reaction, which converts the oil into biodiesel. Apart from that, in
many cases biodiesel is produced by big companies or by individuals but using
complicated and expensive installations.
This work is an attempt to develop a way of producing biodiesel without any use of
external heat, using a simple procedure which could be used by people with a low
knowledge of chemistry or chemical processes. It also seeks to set an example on how
biodiesel can be easily made by oneself without the use of any industrial systems, with a
low budget and limited need of supervision over the process.
In order to achieve that, many trials were undertaken, introducing changes in the different
parameters that are responsible for the changes in the final product. Among them,
changes in the amount and type of catalyst, the way the catalyst is added, the type of oil
used, the time of reaction and the temperature were made. Apart from that, different types
of cleaning were tried, starting by water cleaning and then using powder type products,
Magnesol, D-Sol and Aerogel. A centrifuge was also tried to test its utility when separating
impurities from liquids or different liquid phases. The results of the different trials were
analysed using various tests, the most important being the 3:27 test, the solubility test, the
soap titration and pH measurements.
To sum up, it could be said that the investigation was a success, since it was proved that
biodiesel can be made without the use of any external heat with both alkali and acid
catalysts, as well as with different ways of adding the catalyst. As for the cleaning, good
results were obtained with both dry products and water cleaning, since the soap content of
the biodiesel was reduced in both cases. Apart from that, the centrifuge proved to be valid
to eliminate impurities from raw oil.
TABLE OF CONTENTS
1 INTRODUCTION
1
1.1 Background
1
1.2 Purpose
2
1.3 Limitations
2
1.4 Method
2
1.5 Outline
3
2 VEGETABLE OILS AS FUELS
5
2.1 Constituents and properties of vegetable oils
5
2.2 Sources of oils and fats
6
2.3 Disadvantages of vegetable oils when used as fuels
6
2.4 Methods to improve the quality of vegetable oils
7
3 BIODIESEL
9
3.1 Definition
9
3.2 Transesterification process
9
3.2.1 Reagents
9
3.2.2 Catalyst
12
3.2.3 Mechanism
13
3.2.4 Reaction conditions
15
3.3 Cleaning raw biodiesel
16
3.4 Characteristics of biodiesel
17
3.5 Advantages and disadvantages of biodiesel
18
3.5.1 Advantages of biodiesel
18
3.5.2 Disadvantages of biodiesel
20
4 EXPERIMENTAL PROCEDURE
4.1 Titration
23
23
I
4.1.1 Equipment
23
4.1.2 Reagents
23
4.1.3 Procedure
23
4.2 Transesterification reaction
24
4.2.1 Equipment
24
4.2.2 Reagents
24
4.2.3 Procedure
25
4.3 Separation of the products
28
4.3.1Equipment
28
4.3.2 Procedure
28
4.4 Cleaning biodiesel with water bubbling
28
4.4.1 Equipment
28
4.4.2 Reagents
28
4.4.3 Procedure
28
4.5 Cleaning biodiesel with dry products
29
4.5.1 Equipment
29
4.5.2 Reagents
29
4.5.3 Procedure
30
4.6 3/27 test
30
4.6.1 Equipment
30
4.6.2 Reagents
30
4.6.3 Procedure
30
4.7 Solubility test
31
4.7.1 Equipment
31
4.7.2 Reagents
31
4.7.3 Procedure
31
4.8 Soap test
31
II
4.8.1 Equipment
31
4.8.2 Reagents
31
4.8.3 Procedure
32
4.9 Using the centrifuge
32
4.9.1 Equipment
32
4.9.2 Reagents
32
4.9.3 Procedure
33
5 RESULTS
35
5.1 Titration
35
5.2 Biodiesel production
35
5.2.1 Influence of the catalyst
35
5.2.2 Influence of methanol
38
5.2.3 Influence of the temperature
40
5.2.4 Experiments with different kinds of oils
41
5.3 Soap titration
41
5.4 Cleaning biodiesel
42
5.5 Using the centrifuge
43
6 DISCUSSION
45
6.1 Titration
45
6.2 Biodiesel production
45
6.2.1 Reaction time
45
6.2.2 Influence of the catalyst
45
6.2.3 Influence of methanol
48
6.2.4 Influence of the temperature
49
6.2.5 Experiments with different kinds of oils
51
6.3 Soap titration
52
6.4 Cleaning biodiesel
52
III
6.5 Using the centrifuge
53
6.6 Methanol
53
7 CONCLUSION
55
8 REFERENCES
57
ANNEX I: PROPERTIES OF VEGETABLE OILS
ANNEX II: BIODIESEL STANDARDS
ANNEX III: LABORATORY EQUIPMENT
ANNEX IV: AIR BUBBLING MACHINE
ANNEX V: DRY CLEANING PRODUCTS
ANNEX VI: CENTRIFUGE AND AC DRIVE
IV
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1 INTRODUCTION
1.1 Background
Energy is one of the big worries of the humanity nowadays. In fact, not energy itself, but
the sources of the energy. There are several issues around this topic. On the one hand,
there is the always recurrent end of the oil era. For several years, warnings about the
depletion of the oil reserves have been transmitted. However, nowadays, that is not a
reality, or, at least, it is not a public reality. It is almost impossible to determine how long it
will be possible to live in the petroleum era. Nevertheless, it is a reality that, eventually, the
problem will have to be faced.
As if that was not enough, lately a new and very worrying matter has emerged: the global
warming. It is believed that, due to the high dependancy on fossil fuels, the amount of
carbon dioxide in the atmosphere is increasing. Thus, creating what is called the
greenhouse effect, that prevents heat in the form of infrared radiation from leaving the
earth. Because of this, the earth temperature is said to be increasing, this could cause
several environmental catastrophes and maybe even change the earth as we know it now.
One of the options to reduce our effect on the global warming and, at the same time,
minimise the oil dependency are biofuels. Biofuels have two advantages when compared
to other energy sources: they are a renewable source of energy and they minimise the
carbon dioxide emissions. Therefore, when using them, using oil and the troubles related
to it are avoided. It must be said that biofuels are not the only solution. Actually, biofuels
should never be regarded as if they were the solution to all problems. Biofuels are just one
of the new energy sources that can change our energy consumption habits, but several
other options are needed to achieve the objective of sustainability.
This paper focuses on biodiesel, which is a natural substitute to mineral diesel. Biodiesel is
produced using different kinds of oil, including edible and non-edible vegetable oils, waste
vegetable oils (residual oils used for cooking), animal fats and algae oils. Using a simple
chemical procedure biodiesel can be produced. Afterwards, that biodiesel can be used
blended with mineral diesel in different proportions or without blending, what is called
B100, in diesel engines. Biodiesel is also suitable for direct burning.
There are several advantages when using biodiesel instead of mineral diesel, the most
important ones are the following:
•
It is an alternative to mineral diesel, implying lower dependence on foreign imports of
crude oil.
•
!
Biodiesel is a renewable fuel.
1
•
It has a favourable energy balance. That is, more energy is obtained when using
biodiesel in a diesel engine than the amount that is used for the production of the
biodiesel.
•
Using biodiesel helps reducing greenhouse gas emissions, as stipulated in the Kyoto
Protocol agreement.
•
Harmful emissions of biodiesel are lower than those of mineral diesel, especially
important in environmentally sensitive areas like large cities.
•
It is biodegradable and non-toxic. [1]
There is a final reason that prompted writing this paper. Most of the investigation work
about biodiesel production has been carried out in a way that makes heat necessary for
obtaining it. Therefore, no data could be found in the literature for the process taking place
at room temperature. However, due to the importance of small-scale biodiesel producers, it
would be very interesting if a process avoiding the use of heat was developed. In that way,
both the equipment and the control of the process could be easily simplified, allowing
everyone to produce their own biodiesel without too many complications. In response to
this lack of information, this thesis is an attempt to prove that there is no need to use heat
in order to produce biodiesel.
1.2 Purpose
The aim of this thesis is to explain what biodiesel is and to find the best conditions for
producing biodiesel avoiding the use of heat. It includes the best reaction parameters as
well as cleaning and purifying methods.
1.3 Limitations
The main limitation of this project is the difficulty to determine the quality of the produced
biodiesel. To do so, gas chromatograph equipment is needed, unfortunately, there was no
such equipment available, which has determined the final results. Therefore, it has not
been possible to find out whether the produced biodiesel fulfils the specifications.
However, some other simple tests have been used and the obtained results are positive.
It should also be mentioned that the economic aspect has not been given a foremost
importance when conducting the investigation. Thus, even if the production of suitable/
desired quality biodiesel is guaranteed, it cannot be guaranteed it being economical.
1.4 Method
First of all, familiarisation with the biodiesel producing method had to be achieved. To do
so, different trials were carried out, using different conditions and analysing the obtained
results.
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2
At the same time, to understand the process altogether, literature research was performed.
This, apart from a better knowledge of what biodiesel is and its production implies, was a
good source of how to avoid mistakes and simplify the laboratory process.
The next step was the proper laboratory research, which could be divided into three parts:
1. The first of them is the production of biodiesel. During this period, different trials on
how to produce biodiesel were performed, changing reaction conditions, amounts of
reagents and catalysts, etc.
2. The second period consisted on different trials with different cleaning methods for
biodiesel. Both dry cleaning and water cleaning were tried. In the dry cleaning four
different products were tested: Magnesol and D-Sol, both manufactured by the
Dallas Group of America and two types of Aerogel, manufactured by Svenska
Aerogel.
3. The third stage was devoted to determine the advantages of using a centrifuge in the
process, mainly to see its performance in the separation of two-phase liquid mixtures
or liquids with different kinds of impurities.
During the whole laboratory research different tests were made to understand the results
obtained and improve the method.
Finally, when the all the tests were performed, the results were analysed and the best
method to produce biodiesel without using heat was determined. This will allow
implementing the process at a bigger scale.
1.5 Outline
The first section of the thesis, which is called ʻVegetable oils as fuelsʼ, is an introductory
section in which it is explained the properties of vegetable oils and their constituents, as
well as their sources. Apart from that, a justification for them not being used directly as
fuels is given when talking about their disadvantages. Finally, different methods to improve
the properties of vegetable oils for using them as fuels are explained, including
transesterification.
Next comes a comprehensive chapter about biodiesel. In it, apart from defining what
biodiesel is, the transesterification reaction is explained thoroughly, including reagents,
catalysts, mechanism and conditions. Besides, there is an explanation on how to clean
biodiesel including both dry and water cleaning and all the characteristics of biodiesel are
stated. Eventually, the advantages and disadvantages of biodiesel are displayed.
The third chapter is the experimental procedure. As its name says, what was done in the
lab is explained step by step, following the order of the biodiesel making process. It starts
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3
with the titration. Then, comes the production of biodiesel, where all the different methods
that were tried are explained. Afterwards is stated how the separation of the products and
how the cleaning was done. This is followed by the explanation of the different tests that
were done to verify the quality of the biodiesel. At last, the different trials that were done
with the centrifuge are described.
Following the experimental procedure, there is a chapter that shows all the results
obtained in the lab. The results of all the relevant experiments performed are presented,
for the titration, production of biodiesel, cleaning, soap titration and use of the centrifuge.
After that, a discussion of the results is done, stating their validity and key factors that help
to understand them. It is also discussed which are the best ways to produce biodiesel and
the advantages and disadvantages of different methods. A section about methanol, an
important issue when producing biodiesel, is also included.
The last chapter are the conclusions. In it, the interpretation of everything that was done to
obtain this thesis is conducted, focusing on the key factors.
!
4
2 VEGETABLE OILS AS FUELS
The use of fuels whose source are vegetables is not a new discovery, more than one
hundred years ago, Dr. Rudolf Diesel used peanut oil as fuel for his engine. In fact, Dr.
Diesel designed the original diesel engine to run on vegetable oil [2, 3]. Vegetable oils were
used in diesel engines until the 1920s. However, during that decade, the manufacturers of
diesel engines changed their specifications so as to make them more suitable for the
viscosity of mineral diesel instead of the previously used vegetable oils. There are several
advantages in the use of vegetable oils as diesel, which are: portability; ready availability;
renewability; higher heat content, lower sulphur content and lower aromatic content than
that of mineral diesel; and biodegradability [3].
2.1 Constituents and properties of vegetable oils
The oils and fats are mixtures of liquids. Their main components of raw oils are usually
triacylglycerols (generally > 95%) as well as diacylglycerols, monoacylglycerols and free
fatty acids (FFA). Some other substances like phospholipids, free sterols and sterol esters,
tocols, triterpene alcohols, hydrocarbons and fat-soluble vitamins may also be present [4].
The main difference between vegetable oils and animal fats is the fact that animal fats are
usually saturated, that is, they do not have double-bonds, which makes them solid at room
temperature. On the other hand, vegetable oils are usually liquid at room temperature.
The structure of vegetable oils differs from the structure of mineral diesel. In the case of
the vegetable oils, as many as three fatty acids can be linked to a glycerol molecule using
esters as linkers. Such molecules are the main constituent mentioned above, the
triacylglycerols, while the diacylglycerols and monoacylglycerols refer to the cases when
only two or one fatty acids are linked to a glycerol molecule. The fatty acids present in the
oils will be different from each other, depending on their length and, also, on the number,
orientation and position of the double-bonds [5, 6].
Figure 2.1: A triacylglycerol, a diacylglycerol and a monoacylglycerol (from left to right) [7, 8, 9]
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5
2.2 Sources of oils and fats
There are several types of oils and fats and they can be classified depending on their
source:
Vegetable oils
Non edible oils
Animal fats
Other sources
Soybeans
Almond
Lard
Bacteria
Rapeseed
Abutilon muticum
Tallow
Algae
Canola
Andiroba
Poultry Fat
Fungi
Safflower
Babassu
Fish oil
Micro algae
Barley
Brassica carinata
Tarpenes
Coconut
B. napus
Laxetes
Copra
Camelina
Cooking oil (yellow grease)
Cotton seed
Cumaru
Microalgae (Chroellavulgaris)
Groundnut
Cynara cadunculus
Oat
Jatrophacurcas
Rice
Jathropa nana
Sorghum
Jojoba oil
Wheat
Pongamiaglabra
Winter rapeseed oil
Laurel
Lesquerellafendleri
Mahua
Piqui
Palm
Karang
Tobacco seed
Rubber plant
Rice bran
Sesame
Salmon oil
Table 2.1: Classification of oils depending on their source [10]
More information on different kinds of oils and their properties can be found in the Annex I.
2.3 Disadvantages of vegetable oils when used as fuels
However, several difficulties have been found, mainly concerning the high viscosity of this
kind of oil compared to the viscosity of mineral diesel [4], which usually leads to poor fuel
atomisation, incomplete combustion, carbon deposition on the injector and fuel build up in
the lubricant oils. Moreover, some other physical properties such as their lower volatility
compared to mineral diesel and the reactivity of unsaturated hydrocarbon chains have led
to the necessity of finding more suitable fuels [3, 11].
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6
In table 2.2 a compilation of known problems when using vegetable oils as fuels as well as
their probable cause and potential solution is shown:
Problem
Probable cause
Potential solution
1. Cold weather
starting
High viscosity, low cetane and low flash point
of vegetable oils
Preheat fuel prior to injection.
Chemically alter fuel to an ester.
2. Plugging and
gumming of filters,
lines and injectors
Natural gums (phosphatides) in vegetable oil.
Other ash
Partially refine the oil to remove
gums. Filter to 4-microns
Short term
Very low cetane of some oils. Improper
3. Engine knocking
injection timing
Adjust injection timing. Use higher
compression engines. Preheat fuel
prior to injection. Chemically alter fuel
to an ester
Long term
4. Coking of
High viscosity of vegetable oil, incomplete
injectors on piston combustion of fuel. Poor combustion at part
and head of engine load with vegetable oils.
Heat fuel prior to injection. Switch
engine to diesel fuel when operation
at part load. Chemically alter the
vegetable oil to an ester.
5. Carbon deposits High viscosity of vegetable oil, incomplete
on piston and head combustion of fuel. Poor combustion at part
of engine
load with vegetable oils.
High viscosity of vegetable oil,
incomplete combustion of fuel. Poor
combustion at part load with
vegetable oils
6. Excessive
engine gear
High viscosity of vegetable oil, incomplete
combustion of fuel. Poor combustion at part
load with vegetable oils. Possibly free fatty
acids in vegetable oil. Dilution of engine
lubricating oil due to blow-by of vegetable oil
7. Failure of engine Collection of polyunsaturated vegetable oil
lubricating oil due
blow-by in crankcase to the point where
to polymerisation
polymerisation starts
High viscosity of vegetable oil,
incomplete combustion of fuel. Poor
combustion at part load with
vegetable oils. Increase motor oil
changes. Motor oil additives to inhibit
oxidation
High viscosity of vegetable oil,
incomplete combustion of fuel. Poor
combustion at part load with
vegetable oils. Increase motor oil
changes. Motor oil additives to inhibit
oxidation
Table 2.2: Known problems, probable cause and potential solutions for using straight vegetable oil in diesels [12]
2.4 Methods to improve the quality of vegetable oils
Due to the many problems derived from using vegetable oils as fuels, different methods
have been developed to reduce their disadvantages, the most important being the
following:
a. Dilution with a suitable solvent: it is done by diluting the vegetable oil with mineral
diesel to run the engine.
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7
b. Emulsification: also called microemulsion, it can be defined as a colloidal equilibrium
dispersion of optically isotropic fluid microstructure with dimensions generally into 1–
150 range formed spontaneously from two normally immiscible liquids and one and
more ionic or more ionic amphiphiles. They can improve spray characteristics by
explosive vaporisation of the low boiling constituents in micelles.
c. Pyrolysis: with this method a substance can be converted into another using heat
with the aid of a catalyst in the absence of oxygen or air. With that, a thermal
decomposition of the oil takes place and the heaviest components of the oil are
converted into lighter molecules, which reduces the viscosity. This method is also
used to reduce viscosities of fuel oils and is known as visbreaking. [10]
d. Transesterification: it is the reaction of a fat or oil triglyceride with an alcohol to form
esters and glycerol [3]. After the reaction, two products are obtained, the main
product is what is called biodiesel and the other is glycerol.
Of all the processes mentioned above, the transesterification is the one that gives better
results when the purpose is to reduce the viscosity of oils. Furthermore, glycerol, which
also has a commercial value, is obtained as a by-product. [13]
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8
3 BIODIESEL
3.1 Definition
The term Biodiesel was first used in 1992 in the National Soy diesel Development Board
(now called National Bio Diesel Board) in the United States [10]. Biodiesel is the name
used to refer to a diesel-equivalent fuel that has been obtained from biological sources [4],
using the transesterification reaction. Chemically, biodiesel is a mixture of methyl esters
with long-chain fatty acids and is typically made from nontoxic, biological resources such
as vegetable oils, animal fats, or even waste vegetable oils (WVO) [14].
3.2 Transesterification process
For the production of biodiesel, a vegetable oil or animal fat reacts with ethanol or
methanol in the presence of a catalyst. From this, methyl or ethyl esters are obtained,
which are the components of biodiesel. Along with the esters, glycerol is also produced [3].
That reaction is called transesterification. Stoichiometrically, when the reaction takes
place, for every mole of triglycerides reacting, three moles of alcohol are used. However, a
higher molar ratio of alcohol is usually used for maximum ester production [13]. This will be
more precisely explained in the next pages of the report.
Figure 3.1: Chemical equation of the transesterification mechanism [14]
R1, R2 and R3 are long chain hydrocarbons, sometimes they are also known as fatty
acids. In the presence of the catalyst, the alcohol molecule will be able to break the fatty
acid chains, resulting in two different products, glycerol and a mixture of fatty acid esters
[14].
3.2.1 Reagents
As shown in the reaction above, two reagents are needed, oil and an alcohol. The
decision of which oil and which alcohol to use will depend on many different factors. In
both cases, the availability of some kind of oil and/or alcohol, will probably define which
one to use. However, in many cases, when the reagents to use have to be chosen,
many different aspects have to be taken into account.
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9
In the case of the alcohol, probably the most important reason is the money. Ethanol
and methanol are the most commonly used alcohols, but methanol is usually preferred
because it is cheaper [15]. Moreover, ethanol has a lower transesterification reactivity
than methanol [14]. Of course, other alcohols could be considered, but their higher
prices make them unsuitable, except for the cases when there is a cheap source
available.
Choosing the oil is probably a more complex issue than choosing the alcohol. In this
case many different factors have to be taken into account, not only the price. When
commenting on the price it should be noted that the lower the price, the lower the
quality of the oil. Usually, lower price means a high content of FFAs, which, as will be
shown in the next chapters, involves a bigger production of soap, a by-product that is
not interesting [16]. Furthermore, the soap may lead to difficulties in the reaction and
separation of the products. The oils with higher amount of FFAs are usually waste
vegetable oils, that is, oils that have been used for cooking purposes. In the case of
clean vegetable oils, there should not be so high values of FFAs.
Other important motive to choose one type of oil over other is that the kind of biodiesel
obtained depends highly on the oil that has been used to produce it. Table 3.1 shows
the kinematic viscosity of different oils and biodiesel, obtained from different sources. It
can be appreciated that the oil from which is obtained will affect in different ways the
kinematic viscosity of the product.
Species
Kinematic viscosity of
oil (centistokes, at 40ºC)
Kinematic viscosity of biodiesel
(centistokes, at 40ºC)
Rapeseed
35.1
4,3-5,83
Soybean
32.9
4.08
Sunflower
32.6
4.9
Palm
39.6
4.42
Peanut
22.72
4.42
Corn
34.9
3.39
Canola
38.2
3.53
Cotton
18.2
4.07
Pumpkin
35.6
4.41
Table 3.1: Comparison between the kinematic viscosoties of vegetable oils and the biodiesel obtained from the oils [14]
As in the case of the kinematic viscosity, many other properties will vary depending on
the source of vegetable oil. For additional information, examine Annex I.
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10
Apart from that, there are some other important factors that must be taken into account.
For instance, the possibility of obtaining a kind of vegetable oil depending on the
geographical location and, indeed, the suitability of the biodiesel obtained from that oil
depending on the climate conditions. As an example, palm oil is a good source for
biodiesel when used in tropical countries, but, if it has to be used in Sweden, several
problems could appear because of its high cloud point.
In some cases, when the producer of the biodiesel is also the producer of the oil, the
choice might be which seed to grow instead of choosing the oil type. This is a very
complex matter that will not be deeply analysed in this report, but there are two
parameters which are easy to understand and may be helpful. The first of them is the
production of seed per square meter that has been sown. The second is the yield of oil
and meal obtained by extraction of the seed. In table 3.2 data for the second parameter
of the major oilseeds can be seen:
Oilseed
Oil
Meal
Soybean
18.3
79.5
Cottonseed
15.1
57.4
Groundnut
40.3
57.2
Sunflower
40.9
46.9
Rapeseed
38.6
60.3
Palmkernel
44.6
54.0
Copra
62.4
35.4
Linseed
33.3
64.2
Table 3.2: Yields (%) of oil and of meal obtained by extraction of the major oilseeds [4]
As shown in the table, the variation on the yield of oil depending on the oilseed is
significative. Thus, it should be considered when deciding the oilseed to use. In
addition, other factors such as environmental conditions or geographical location should
be contemplated.
In conclusion, choosing the oil is a complex process, which will be highly determined by
its price, but some other factors should also be studied. Nevertheless, the amount of
free fatty acids in the oil is a good point to start with, because it may cause several
difficulties when making biodiesel. Therefore, using oil with low FFA content is always
recommended. Since the cost of raw materials accounts for about 60–80% of the total
cost of biodiesel production, choosing a right feedstock is very important [10].
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11
3.2.2 Catalyst
The presence of a catalyst is mandatory for this chemical reaction to happen in normal
conditions. Several types of catalysts have been tried, both heterogeneous and
homogeneous. The homogeneous catalysts can be divided into two categories, alkalis
and acids. The most common alkali catalysts are potassium hydroxide, potassium
methoxide, sodium hydroxide and sodium methoxide. Alternately, the acid catalysts
include products like sulphuric acid, hydrochloric acid and sulphonic acid.
The other group is formed by heterogeneous catalysts. It includes enzymes, titaniumsilicates, alkaline-earth metal compounds, anion exchange resins and guanadines
heterogeneisated on organic polymers [1].
A third option is also available, it is using supercritical methanol. In this case, no catalyst
is needed, but, on the other hand, high temperature and high pressure conditions i.e.
573 K and 20 MPa, are needed [13].
Another option that should be mentioned is the use of ultrasonic reactors and
microwaves. Ultrasonic reactors have been tried with good results, however, using a
catalyst is still necessary [17]. As for microwaves, they are used combined with both
heterogeneous and homogeneous catalysts, obtaining lower reaction times than when
no microwaves are used [18, 19].
Depending on the type of catalyst used, several advantages and disadvantages will be
found. The most widely used catalyst type are the alkalis and, among the alkalis, the
most used is the potassium hydroxide. This is because with this kind of catalyst the
process is fast and the conditions are moderate. However, the disadvantage appears is
the formation of soaps, which are produced by neutralising the free fatty acid in the oil
and triglyceride saponification. Both soap formations are undesirable side-reactions,
because they partially consume the catalyst, decrease the biodiesel yield and
complicate the separation and purification steps [1].
Acid catalysts have not been used as widely as alkali catalysts. Its main advantage is
that the presence of free fatty acids will not affect the reaction. Moreover, acid catalysts
can catalyse both esterification and transesterification at the same time. The
esterification is a chemical reaction in which an alcohol and an acid react, producing an
ester. This means that the FFAs, instead of producing soap as in the alkali catalysed
reaction, will produce esters, which is the product of interest. However, there are some
disadvantages that have induced the higher use of alkali catalysts, the most important
are: a slower reaction rate, requirement of high reaction temperature, high molar ratio of
alcohol to oil, separation of the catalyst, serious environmental and corrosion related
problems [20].
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12
The main advantage of the heterogeneous catalysts is that the post-treatment of the
products is easier, because it facilitates the separation and minimises the purification.
In addition, there is no production of soaps. On the contrary, it requires extreme reaction
conditions and the low methyl ester yield and high reaction time are more favourable in
the case of the alkali catalysed transesterification [1].
Table 3.3 is a summary of the different kinds of catalysts that can be used, as well as
their advantages and disadvantages:
Type of catalyst Advantages
Disadvantages
Homogeneous
base catalyst
Very fast reaction rate - 4000 times faster
than acid-catalysed transesterification
Reaction can occur at mild reaction condition
and less energy intensive
Catalysts such as NaOH and KOH are
relatively cheap and widely available
Sensitive to FFA content in the oil
Soap will form if the FFA content in the oil is more
than 2 wt%
Too much soap formation will decrease the biodiesel
yield and cause problems during product purification
especially generating huge amounts of wastewater
Heterogeneous
base catalyst
Relatively faster reaction rate than acid-
Homogeneous
acid catalyst
Insensitive to FFA and water content in the oil
Preferred method if low-grade oil is used
Esterification and transesterification occur
simultaneously
Reaction can occur at mild reaction condition
and less energy intensive
Poisoning of the catalyst when exposed to ambient
air
catalysed transesterification
Sensitive to FFA content in the oil due to its basicity
Reaction can occur at mild reaction condition property
and less energy intensive
Soap will be formed of the FFA content in the oil is
more than 2 wt %
Easy separation of catalyst from product
Too much soap formation will decrease the biodiesel
High possibility to reuse and regenerate the
yield and cause problems during product purification
catalyst
Leaching of catalyst active sites may result in product
contamination
Very slow reaction rate
Corrosive catalyst such as H2SO4 used can lead to
corrosion on reactor and pipelines
Separation of catalyst from product is problematic
Heterogeneous
acid catalyst
Insensitive to FFA and water content in the oil Complicated catalyst synthesis procedures lead to
higher cost
Preferred method if low-grade oil is used
Normally, high reaction temperature, high alcohol to
Esterification and transesterification occur
oil molar ratio and long reaction time are required
Energy intensive
simultaneously
Leaching of catalyst active sites may result to product
Easy separation of catalyst from product
contamination
Enzyme
Preferred method if low-grade oil is used
Transesterification can be carried out at low
reaction temperature, even lower than
homogeneous base catalyst
Only simple purification step is required
Very slow reaction rate, even slower than acidcatalysed transesterification
High cost
Sensitive to alcohol, typically methanol can
deactivate the enzyme
Table 3.3: Advantages and disadvantages of different types of catalysts [20]
3.2.3 Mechanism
The mechanism for the transesterification is a series of consecutive reversible
reactions, where a triglyceride is converted stepwise to diglyceride, monoglyceride and,
finally, glycerol. In each one of the steps a mole of ester is liberated. They are reversible
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13
reactions even though the equilibrium tends toward the products, that is, glycerol and
the free fatty esters.
Depending on the type of catalyst chosen, the mechanism of the reaction will vary. In
the case of the alkali catalysed reaction, the mechanism was formulated in three steps,
in the first of them the anion of the alcohol will attack the carbonyl carbon atom of the
triglyceride and a tetrahedral intermediate will be formed. The second step implies that
intermediate reacting with an alcohol to regenerate the anion of the alcohol. Finally, in
the third step, a rearrangement of the tetraheldral intermediate takes place, resulting in
the formation of a fatty acid ester and a diglyceride.
Figure 1.3: The mechanism of the alkali catalysed transesterification [21]
The catalyst is not the alkali itself, but the product created by mixing the alkali with the
alcohol, which is an alkoxide group. When this reaction takes place a small amount of
water is generated, which may cause problems due to soap formation during
transesterification [21].
On the other hand, if the catalyst used is an acid, the mechanism will be defined by it,
therefore, it will be an acid mechanism and the trigger will be a hydron.
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14
Figure 1.4: Acid catalysed transesterification [10]
In this case, the first step is the attack of the hydron of the acid on the carbonyl carbon
atom, forming the tetrahedral intermediate. In the second step the alcohol will react with
the intermediate, due to its negative charge. The last step is the rearrangement step,
with the hydron of the catalyst being liberated again and the formation of the diglycerol
and the ester.
3.2.4 Reaction conditions
Once the reaction is known, the conditions in which it happens should be determined.
The parameters that will affect the reaction to a higher extent are: temperature, amount
of alcohol, type and amount of catalyst, reaction time. Further, each of them will be
discussed individually.
3.2.4.1 Temperature
Temperature values for the transesterification reaction vary depending on the literature
source. It is well known that higher temperatures speed up the reaction and shorten the
reaction time. Apart from that, higher temperatures usually mean obtaining higher ester
yields [11]. However; It should also be noted that if the reaction temperature is higher
than the boiling point of the alcohol, it will evaporate, resulting in a lower yield [13]. It is
also an accepted fact that usually the optimum temperatures for the transesterification
range between 50 and 60ºC, depending on the kind of oil to be processed [14]. In the
case of rapeseed oil, the optimum temperature value for its methanolysis has been
found to be 65ºC [11].
3.2.4.2 Reaction time
The reaction time clearly influences the outcome of the reaction, since the conversion
rate increases with the reaction time [21]. If the reaction time is not long enough the
ester yield will be low, therefore, part of the oil will be unreacted. For the rapeseed oil,
when heat is used in the reaction, the optimum reaction time is two hours [11].
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15
3.2.4.3 Methanol/oil molar ratio
This is one of the most important factors that can affect the ester yield. It is related to
the type of catalyst used, depending on that, the optimum value for the process can be
obtained. Higher molar ratios give a higher ester yield in a shorter time. Usually, when
using acid catalysts higher molar ratios are needed, probably because the use of acid
catalysts is related to oils with high FFA content [21]. When rapeseed oil is
transesterified using potassium hydroxide as a catalyst, the optimum molar ratio is 6:1.
3.2.4.4 Catalyst concentration
This parameter is highly affected by the kind of catalyst used, different catalysts will
require different concentrations. Even if they belong to the same group (as in the case
of potassium hydroxide and sodium hydroxide), different concentrations will be
necessary to attain the same yields. Therefore, the optimum value for every catalyst will
have to be determined by titration. If the amount of catalyst is higher than the optimum,
there will be a decrease in the yield of methyl esters due to the formation of soap in
presence of high amount of catalysts, which apart from lowering the yield increases the
viscosity of the reactants [11].
3.2.4.5 Mixing
Mixing is mandatory for the reaction to take place. Without mixing, the reaction only
occurs in the interface between the methanol and the oil and it is very slow to be viable.
Therefore, a mixing device is needed in the reactor used for the process [11].
3.3 Cleaning raw biodiesel
When the transesterification reaction is finished, two products are obtained, biodiesel and
glycerol. Both can be separated by sedimentation, since, due to their different densities,
form two different liquid phases.
After the separation, raw biodiesel is obtained. This product still contains several different
compounds that should be eliminated: residual catalyst, water, unreacted alcohol, free
glycerol and soaps. Usually, before the cleaning step, methanol is removed using an
alcohol stripper to prevent excess alcohol from entering the wastewater effluent in the
case of the water cleaning and to follow the instructions marked by the producer when it
comes to dry cleaning.
Both glycerol and alcohol can be easily removed by using water washing because they are
highly soluble in water. By using water residual salts and soaps can also be eliminated.
Water also helps to prevent the precipitation of saturated fatty acid esters and retards the
formation of emulsions. Different stages have to be done to wash the biodiesel, which will
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16
be washed when the water phase becomes clean. Afterwards, the water is separated from
the biodiesel, they can be easily separated due to their density difference.
Dry washing consists of using different products which will substitute the water in order to
remove impurities. In this case, the free glycerol level is reduced and soaps are also
removed. The main advantage is the fact that no water is used, eliminating any problems
with wastewater effluents. Among the different products that can be used, commercial
brands such as Magnesol or D-Sol can be found. [14]
3.4 Characteristics of biodiesel
After the transesterification reaction and the cleaning, biodiesel is obtained. It is a clear
amber-yellow liquid. Due to the conversion of triglycerides into esters, the molecular
weight of biodiesel is one-third of the triglyceride, the viscosity is reduced by a factor of
about eight and the volatility is also increased. This means that the viscosity of biodiesel is
similar to the viscosity of diesel fuels. It should also be noted the fact that the esters of
biodiesel contain 10-11% oxygen by weight, resulting in more combustion in an engine
than hydrocarbon-based diesel fuels. The cetane number of biodiesel is around fifty.
Biodiesel is considered as a clean fuel because it has no sulphur or aromatics and its
content in oxygen, which is helpful to burn it completely. Due to its higher cetane number it
improves the ignition quality even if it is blended with mineral diesel. [10]
It has better lubricant properties than diesel fuel. It is also non-toxic and biodegrades
quickly. The associated risk of handling, transporting and storing biodiesel is lower than
that of mineral diesel. [3]
Table 3.4 shows a comparison of different fuel properties of petrodiesel and biodiesel:
!
Fuel Property
Test method
ASTM D975 (Diesel)
ASTM D6715 (Biodiesel)
Flash point
D 93
325 K min
403 K
Water and sediment
D 2709
0,05 max %vol
0,05 max %vol
Kinematic viscosity (at 313 K)
D 445
1,3-4,1 mm2/s
1,9-6,0 mm2/s
Sulphated ash
D 874
-
0,02 max %wt
Ash
D 482
0,01 max %wt
-
Sulphur
D 5453
0,05 max %wt
-
Sulphur
D 2622/129
-
0,05 max %wt
Copper strip corrosion
D 130
No 3 max
No 3 max
Cetane number
D 613
40 min
47 min
Aromaticity
D 1319
35 max %vol
17
Fuel Property
Test method
ASTM D975 (Diesel)
ASTM D6715 (Biodiesel)
Carbon residue
D 4530
-
0,05 max %mass
Carbon residue
D 524
0,35 max %mass
-
Distillation temp (90% volume
recycle)
D 1160
555 K min-611 K max
Table 3.4: ASTM standards of biodiesel and petrodiesel fuels [3]
More information about biodiesel standards can be found in the Annex II.
3.5 Advantages and disadvantages of biodiesel
As it has been mentioned above, biodiesel can be used as a substitute for mineral diesel.
When using it, several different advantages and disadvantages can be found. In the lines
below, those will be explained in detail.
3.5.1 Advantages of biodiesel
The advantages of using biodiesel can be divided into three categories:
3.5.1.1 Economic impacts
- Sustainability: Biodiesel promotes sustainability because it is a renewable fuel, with no
carbon dioxide emissions and that avoids the use of fossil fuels.
- Fuel diversity: It means more competition and, also, more options for the consumer, that
way the quality of the products is enhanced and the prices are lower.
- Increased number of rural manufacturing jobs: In order to grow the seeds, produce the
oil and then the biodiesel, several workers are needed. Usually, this will happen in rural
areas, meaning that more jobs will be available in those areas.
- Increased income taxes: Biodiesel, as any other fuel, is charged with taxes by the
government, which receive more income taxes if biodiesel is used.
- Increased investments in plant and equipment: For the production of biodiesel it is
necessary to build production plants and buy equipment.
- Agricultural development: As in the case of the rural manufacturing jobs, since it is
necessary to grow the seeds, this will mean that the agriculture in the area will develop.
- International competitiveness: While the petroleum reserves are concentrated in just a
few countries, in every country of the world biodiesel can be produced. Due to this, many
countries could be able to join the fuels market, which would make it more competitive.
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18
- Reducing the dependency on imported petroleum: The reason is fundamentally the
same as the stated above, biodiesel can be produced by any country and being a
substitute for diesel, there will be a lower necessity to import it.
- Inherent lubricity: The esters forming biodiesel have been analysed and it has been
found that they show good potential as base stock in biodegradable lubricant formation.
- Higher cetane number: As shown in Table 3.4, biodiesel has a higher cetane number
than diesel. [22, 23, 24, 25]
3.5.1.2 Environmental impacts
- Greenhouse gas reductions: Complete combustion of diesel fuel releases 3.11 kg of CO2
per kilogram while biodiesel releases 2.86 kg. Moreover, the carbon dioxide released by
petroleum diesel was fixed from the atmosphere during the formative years of the earth.
On the other hand, carbon dioxide released by biodiesel was fixed by plants in a recent
year and will be recycled by the next generation of crops. It has been calculated that for
each kilogram of diesel not used an equivalent of 3.11 kg of CO2, plus an additional
15-20% for reduced processing energy, is not released to the atmosphere.
- Biodegradability: Biodiesel is non toxic and degrades about four times faster than
petrodiesel. This is enhanced by its oxygen content, higher than the oxygen content of
mineral diesel. Data obtained from a study shows that after 28 days, biodiesel fuels were
biodegraded from 77 to 89%, while diesel fuel was only 18% biodegraded. Table 3.5
shows biodegradability data of different fuels:
Fuel sample
Degradation in 28 d (%)
Gasoline (91 octane)
28
Heavy fuel (Bunker C oil)
11
Refined rapeseed oil
78
Refined soybean oil
76
Rapeseed oil methyl ester
88
Sunflower seed oil methyl ester
90
Table 3.5: Biodegradability data of petroleum and biofuels [4]
- Higher combustion efficiency: In the literature different studies can be found supporting
that esters prepared from oils can replace diesel oil. Moreover, it is stated that, under
favourable conditions, biodiesel exceeds the performance of diesel fuel.
- Improved land and water use: Using biodiesel encourages using land for vegetable crops
and, also, sensible use of water.
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19
- Carbon sequestration: As explained above, when biodiesel crops are grown, the plants
fix carbon dioxide.
- Lower sulphur content: Biodiesel contains less sulphur than diesel, which means lower
sulphur emissions.
- Lower aromatic content: As in the case of the sulphur, the aromatic content of biodiesel
is lower than that of mineral diesel, leading to lower aromatic emissions.
Pure biodiesel
20% Biodiesel + 80% petrodiesel
B100
B20
Total unburned hydrocarbons (HC)
-67
-20
Carbon monoxide
-48
-12
Particulate matter
-47
-12
NOx
+10
+2
Sulphates
-100
-20
Polycyclic aromatic hydrocarbons
-80
-13
Emission type
Table 3.6: Average biodiesel emissions (%) compared to conventional diesel, according to EPA (2002).
- Less toxicity: Biodiesel is non-toxic. [22, 23, 24, 25]
3.5.1.3 Energy security
- Domestic targets: Using biodiesel helps achieve targets in domestic fuel production.
- Supply reliability: Since it can be produced locally, the reliability of the supply is higher
than that of internationally obtained products.
- Higher flash point: It has a higher flash point than diesel and that makes it less
dangerous because it evaporates with more difficulty.
- Reducing use of fossil fuels: Being a direct substitute of diesel, it reduces its use.
- Ready availability: Production of biodiesel takes the time necessary to grow the crop,
make the oil and then the biodiesel. Even if it may take a year, compared to the time that
it takes to produce diesel fuel, it is a short period. This means that it can be available in a
short period of time.
- Renewability: Because of its origin, which is oil produced from a crop, it is renewable
because this source can be restarted as many times as wanted. [22, 23, 24, 25]
3.5.2 Disadvantages of biodiesel
Even if biodiesel has several advantages, its use also implies some disadvantages that
should be mentioned:
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20
- Agricultural feedstock is needed to produce biodiesel and at some times its availability
might be constrained due to its necessity to produce food. This may impose limits on the
production of biodiesel.
- The kinematic viscosity of biodiesel is higher than that of diesel fuel. This affects fuel
atomisation during injection and requires modified fuel injection systems.
- Biodiesel has high oxygen content, which, when combusted, produces higher NOx levels
than the produced by mineral diesel.
- Oxidation of biodiesel happens more easily than oxidation of diesel, so, when it is stored
for long periods some products that may be harmful to the vehicle components might be
produced.
- Biodiesel is hygroscopic, it absorbs water easily. Water content of biodiesel is limited by
the standards. Thus, contact of biodiesel with sources of humidity should be avoided.
- Partly due to its local and home production, the biodiesel produced may not comply with
European or US standards and it may cause corrosion, fuel system blockage, seal
failures, filter clogging and deposits at injection pumps.
- Its lower volumetric energy density means that more fuel needs to be transported for the
same distance travelled when using biodiesel than when using diesel.
- It can cause dilution of engine lubricant oil, requiring more frequent oil change than in
standard diesel-fuelled engines.
- A modified refuelling infrastructure is needed to handle biodiesel, which adds to its total
cost. [10]
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21
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22
4 EXPERIMENTAL PROCEDURE
For the realisation of this thesis, several different laboratory procedures were carried out.
In this section, all of them will be explained in detail. More information about the equipment
used for the experimental procedure can be found in the Annex III.
4.1 Titration
Before starting the biodiesel production, a test has to be performed. This test is called
titration and it is used to determine the amount of free fatty acids present in the oil. This is
compulsory to determine the amount of catalyst needed for the reaction.
4.1.1 Equipment
The equipment needed for the titration is:
- Magnetic stirrer
- Burette
- Plastic and volumetric pipettes
- Pipette bulb
- Volumetric flask
- Weight balance
- Erlenmeyer flask
4.1.2 Reagents
The following reagents are needed to perform the titration:
- Water
- Potassium or sodium hydroxide
- Phenolphthalein
- Isopropyl alcohol
- Vegetable oil
4.1.3 Procedure
The first step to take will be preparing the standard solution that will be used for the
titration. The standard solution consists of 1 gram of catalyst (potassium or sodium
hydroxide) diluted in 1 litre of water. To do so, 1 gram of catalyst is weighed in the
balance, then diluted with water. This liquid is then poured in a volumetric flask and
water is added till the volume is one litre.
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23
Once the standard solution is ready, the titration itself can be performed. To do so, a
burette filled with the standard solution has to be prepared. On the other hand, an
Erlenmeyer flask with 10 mL of isopropyl alcohol and three drops of phenolphthalein
has to be set. Then, it will be put on the magnetic stirrer. Standard solution is added till
the solution turns pink, at that point the volume of standard solution is written down.
Next, 1 mL of oil is incorporated and standard solution is added again till the solution
turns pink. The new volume of standard solution is noted. The difference between the
second and first volume is the amount of catalyst that has to be added apart from the 9
grams that are the base amount.
The calculations for that are as follows:
x mL of KOH standard solution for 1 mL of vegetable oil
x L of standard solution for 1 L of vegetable oil
x L of standard solution contains x g of KOH
From there, the amount that has to be added for the transesterification is calculated as:
9 + x g per litre of vegetable oil. [15]
4.2 Transesterification reaction
The transesterification reaction is the most important stage when producing biodiesel.
Several different experiments were tried to find the most suitable procedure. First of all,
the equipment and reagents needed will be explained. Afterwards, a description of the
process will be given.
4.2.1 Equipment
The following equipment is needed for the transesterification reaction:
- Magnetic stirrer
- Volumetric pipette
- Pipette bulb
- Weight balance
- Erlenmeyer flask
- Graduated cylinder
4.2.2 Reagents
Several different kinds of catalysts, oils and alcohols can be used for the
transesterification reaction, however, the ones used for the realisation of this paper are:
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24
- Rapeseed, sunflower, linseed and hemp oils.
- Methanol
- Potassium hydroxide, sodium hydroxide and sulphuric acid.
4.2.3 Procedure
Several different procedures were tried to produce biodiesel. Many differences can be
found among them. In the next sections all of them will be explained thoroughly.
4.2.3.1 Amount and type of catalyst
Since alkali catalysts are the most suitable for this reaction, they were chosen to
perform the transesterification. However, a choice between potassium and sodium
hydroxide had to be done. Moreover, the exact amount of catalyst to be used had to be
determined. This is so, because, even if the transesterification is supposed to give the
amount of catalyst needed, it was found that using that quantity the reaction was
incomplete.
To establish those parameters, the methodology used was very simple. Fixed amounts
of rapeseed oil and methanol were used, 500 mL for the rapeseed oil and 100 mL for
the methanol, while the amount and type of catalyst was varied. The amounts of both
potassium and sodium hydroxide in the first trials were the obtained on the
transesterification. Afterwards, lower and higher amounts were tried.
The first step before starting the reaction was mixing the catalyst and the alcohol, using
the stirrer. Afterwards, this compound, called methoxide, was combined with the oil,
using stirring again during the whole reaction period. The reaction time was set to 5
hours and the temperature that of the room, which was 21 ºC approximately. This
means that no heat was used.
4.2.3.2 Amount of methanol
This case was an attempt to determine whether or not it was possible to use reduced
amounts of methanol for the reaction. Therefore, the amount of methanol was the only
changing factor while all the others were kept constant. Lower values than 100 mL were
tried. The conditions used were 6.8 grams of potassium hydroxide, 500 mL rapeseed
oil, 5 hours as reaction time, continuous stirring and room temperature. Once again, the
potassium methoxide was prepared before the actual reaction started and then it was
added to the oil.
4.2.3.3 Reaction temperature
Despite the fact that the purpose of the thesis is using no heat for the transesterification
reaction, some trials were carried out using heat to compare the final results of both
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25
options. Both 40 and 60 ºC were tried. Apart from that, the reaction was also tried at a
temperature lower than room temperature, approximately 2 or 3 ºC.
The factors used, were 500 mL rapeseed oil, 100 mL of methanol and 6.8 grams of
potassium hydroxide. The stirring was continuous in the case of the reactions at 40 and
60 ºC and the reaction time was 5 hours. However, due to some technical difficulties,
that was not possible for the low temperature trial, therefore, the stirring was done in the
next way: 30 minutes stirring, 50 minutes without stirring, 10 minutes stirring, 50
minutes without it. The last part, the 10-50, was repeated until the reaction time was 5
hours. As in all the previous cases, the methoxide was prepared first and then it was
added to the oil.
4.2.3.4 Way of adding the catalyst
As stated above, the common method consists of preparing the methoxide before
mixing it with the oil. However, there was not a convincing reason for this.
Consequently, an experiment in which the methanol and the potassium hydroxide were
added without being previously mixed was attempted.
The conditions were 500 mL rapeseed oil, 100 mL methanol, 6.8 grams of potassium
hydroxide, 6 hours reaction time, room temperature and continuous stirring. The
methanol and the potassium hydroxide were added to the rapeseed oil at the same
time, without previous mixing.
Another way of adding the catalyst was also tried, in this case, the potassium hydroxide
and the methanol were mixed to form the potassium methoxide before adding it to the
oil, but not all the methoxide was added at the beginning, just two-thirds of it. The other
third was added after some reaction time had taken place and the glycerol obtained had
been separated. This was an endeavour to see if the catalyst amount could be reduced.
Two different amounts of catalyst were tried, 6.2 and 6.8 grams of potassium hydroxide.
As in the previous cases, 500 mL of oil and 100 mL of methanol were used, as well as
continuous stirring and room temperature. As explained above, the methoxide was
prepared and just two-thirds (by volume) were added at the beginning. After two hours,
the reaction was stopped and the products were poured into a separatory funnel, where
they stayed for half an hour, enough time for the two phases to separate. When the time
had passed, the glycerol was extracted, the biodiesel was set on the stirrer again and
the rest of the methoxide was added. Two extra hours were necessary to complete the
reaction.
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26
4.2.3.5 Stirring
Stirring is mandatory for this reaction to start, because, without stirring, reaction only
happens in the interface, which goes to a very low extent. Therefore, stirring is needed,
at least, in the beginning, if not during the whole reaction time. To determine if
continuous stirring is necessary, an experiment was made, using the same stirring times
as in the case of the cold temperature, that is, 30 minutes stirring, 50 minutes without
stirring, 10 minutes stirring, 50 minutes without stirring and repeating this last period
until the reaction time was 5 hours.
The rest of the setup was 500 mL rapeseed oil, 100 mL methanol, 6.8 grams of KOH
and the methoxide was first produced and then added to the rapeseed oil.
4.2.3.6 Type of oil
The reaction parameters were designed to be optimum for rapeseed oil, but it had to be
proven that they would work with any other kind of oil as long as the amount of free fatty
acids was not too elevated. To do so, samples of sunflower oil and linseed oil were
tested. The reaction conditions were 500 mL of oil, 100 mL of methanol, 6.8 grams of
potassium hydroxide, 5 hours reaction time, continuous stirring and room temperature.
4.2.3.7 Acid catalyst
While alkali catalysts have a higher yield and shorter reaction times, they are not
recommended when the content of free fatty acids in the oil is too high (usually when
the value obtained in the titration is higher than 3). In this cases, an acid catalyst,
sulphuric acid with a purity of 98%, is used.
The first part of this process is different from the process used for the alkali catalyst.
Initially, the amount of acid has to be calculated, it is done with this formula:
Millilitres of H2SO4 per litre of oil = (Initial Titration - Target Titration) * 0.2 [26]
Since the alkali method is recommended for titration values lower than three, the target
titration was set in that value. Once the millilitres of sulphuric acid were calculated, the
reaction could be started. As previously, the acid was first mixed with the methanol and
then added to the oil. However, there are some differences in this method, because in
the first part only 50 mL of methanol were added and the reaction time was
approximately one day (it was always left overnight). Apart from that, the other factors
were maintained in the same way, 500 mL of oil, continuous stirring and room
temperature were used.
After the first part of the reaction, the liquid was poured into a separatory funnel, where
the water remanent was extracted. Afterwards, a titration was made to determine
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27
whether the amount of free fatty acids was correct and then the alkali reaction was
started. This process was done twice with different oils, old rapeseed oil and hemp oil.
For the hemp oil, which gave the highest titration amount, 100 mL of methanol were
used in the alkali part. On the other hand, for the old rapeseed oil, only 50 mL were
used. Besides, the amount of catalyst was the obtained in the titration, the reaction time
was 5 hours, continuous stirring was used and it was done at room temperature. As in
the other cases, the potassium methoxide was first mixed and then it was added to the
oil. [15, 26]
4.3 Separation of the products
4.3.1Equipment
The only piece of equipment which is needed for the separation of glycerol and
biodiesel is a separatory funnel.
4.3.2 Procedure
The liquid product obtained from the transesterification reaction, which was basically
formed by glycerol and biodiesel, is placed in the separatory funnel. It stays there
overnight (around 18 hours) and then, the glycerol, which is the heaviest product, is
separated because it forms the phase which stays in the bottom.
4.4 Cleaning biodiesel with water bubbling
4.4.1 Equipment
- Separatory funnel
- Air flow machine (more information about this can be found in the Annex IV)
4.4.2 Reagents
- Raw biodiesel
- Water
4.4.3 Procedure
The raw biodiesel which is obtained after the separation from the glycerol needs to be
cleaned. One of the possibilities to achieve the cleaning is using water and bubbling air
through it. This will dissolve the soap, unreacted oil and other impurities which can be
found in the raw biodiesel.
The steps to follow are not complicated. Usually, three different cleaning stages are
done. The first and the last are short, about one hour, and the intermediate is long, more
!
28
than one day. The water volume needed for every step is approximately the same as
the biodiesel volume.
The process starts by putting the biodiesel in the separatory funnel, then, the water is
added carefully. Next, the air bubbling is set and started. It is important that the bubbles
are not too big or too fast, this may create an emulsion between the water and the
biodiesel and the biodiesel might not be recovered. To set the air bubbling, a hose is
introduced in the lowest part of the separatory funnel. After the stage time, the bubbling
is stopped, the liquids are left to settle for about half an hour and then the water is
extracted. Afterwards, either a new stage is started or the biodiesel is already prepared
to be used. It should be noted that it is important for the water after the last stage to be
clean, which means that all the impurities have already been eliminated. It is also
recommended, for that reason, the longest stage not to be the last, because it is in that
stage when the majority of the impurities are removed and the water will not be clear
after that.
4.5 Cleaning biodiesel with dry products
4.5.1 Equipment
- Weight balance
- Magnetic stirrer
- Erlenmeyer flask
- Büchner funnel with elastomer adapter
- Kitasato flask
- Hose
- Vacuum pump
- Filter paper
4.5.2 Reagents
Several different cleaning agents were tried, more information about them can be found
in the Annex V.
- Magnesol
- D-Sol
- Aerogel
- Raw biodiesel
!
29
4.5.3 Procedure
The first step to take is to weigh the amount of drying product needed. This will vary
depending on the using instructions provided by the manufacturer. In the case of the DSol it is 0.5% in weight, while for aerogel and magnesol it is 1.5%, also in weight. All
the products are powder like solids. Oil is added till the 100% in weight value is
achieved and then the mixture is stirred for twenty minutes. After that time, a vacuum
filtration is done, using the Büchner funnel, the Kitasato flask and filter paper. The
filtration is done twice, using the same paper where a cake of powder has been created,
which, once created, will act as the filtering medium. When the second stage of the
filtration is finished, the biodiesel is cleaned and ready to be used.
4.6 3/27 test
4.6.1 Equipment
- Pipettes
- Pipette bulb
- Test tubes
4.6.2 Reagents
- Methanol
- Raw biodiesel
4.6.3 Procedure
The 3/27 test, also called Jan Warnquist test after its developer, is used to find the
degree in which triglycerides are converted into methyl esters in the transesterification
reaction. Therefore, with this test, the development of the reaction can be known. To
perform the test, methanol and raw biodiesel are needed. First, 27 parts of methanol
are put into a test tube. Afterwards, three parts of raw biodiesel are added and the
content of the tube is agitated. After a resting period of 30 minutes, it can be checked
whether any precipitate has appeared, if there is precipitate the test has not been
passed, meaning that the reaction is not complete. If the test is performed properly, and
a batch of fuel passes, (there is no visible precipitate) then the fuel is likely to be
converted very close to the ASTM standard for conversion of 0.24% total glycerides or
better. [27]
!
30
4.7 Solubility test
4.7.1 Equipment
- Pipettes
- Pipette bulb
- Test tubes
4.7.2 Reagents
- Raw biodiesel
- Water
4.7.3 Procedure
Methyl esters, as well as vegetable oil, are not miscible with water. Therefore, a good
quality biodiesel should have a low solubility in water, which indicates that not many
impurities are present. To prove so, a simple test was performed, which consisted of
mixing one volume of raw biodiesel with one volume of water in a test tube. After
shaking the tube, it was allowed to settle for half an hour. Then, the extent to which
biodiesel is dissolved in water, the turbidity of biodiesel due to water and the amount of
soap in the interface could easily be seen with a naked eye.
4.8 Soap test
4.8.1 Equipment
- Erlenmeyer flask
- Pipettes
- Pipette bulb
- Burette
- Magnetic stirrer
- Balance
4.8.2 Reagents
- Isopropyl alcohol
- Phenolphthalein
- 0.01 N HCl
- 0.04% Bromophenol blue in water
- Biodiesel
!
31
4.8.3 Procedure
The soap test is used to determine the amount of soap in raw biodiesel. With it, the
quantity of dry cleaning product can be determined. It is also useful to know the quality
of the obtained biodiesel.
The grams of soap in a gram of biodiesel can be determined with the formula shown in
figure 4.1.
B ⋅ 0.1
Grams of soap / gram of sample =
B = mL 0.01 N HCl
W = g biodiesel
mol HCl
g
⋅ 320.56
l
mol soap
1000 ⋅W
Figure 4.1: Calculation of the amount of soap in a biodiesel sample [28]
The procedure of the test starts with the preparation of an Erlenmeyer flask with 100
mL of isopropyl acid and 5 drops of phenolphthalein. Then, ten grams of biodiesel are
added. If the mixture turns pink, it means that there is some unreacted catalyst in the
raw biodiesel. In that case, 0.01N HCl has to be added till the pink colour disappears. In
the case it doesnʼt, that step is skipped and the next is started. In the next step, 18
drops of bromophenol blue are added to the mixture and then it is weighed. The colour
of the liquid will now be blue. After this, HCl, which is contained in a burette, is
incorporated while stirring until the colour turns yellow. The Erlenmeyer flask is weighed
again and the volume of HCl used is noted. [28]
4.9 Using the centrifuge
4.9.1 Equipment
The centrifuge is the most important piece of equipment needed in this part of the
experimental procedure. More information about it and about the AC drive can be found
in the Annex VI.
- Centrifuge
- AC drive
- Funnel
- Tube
4.9.2 Reagents
- Biodiesel
- Oil
!
32
- Glycerol
- Water
4.9.3 Procedure
The purpose of using the centrifuge was to find out whether or not it can be used for the
separation of different liquids and mixtures of liquids that are often found when making
biodiesel. In this case, the centrifuge was connected to an AC Drive, allowing it to reach
6000 rpm.
The procedure was very simple, the first step was to switch on the centrifuge and set it
to the maximum speed. Afterwards, the liquid that had to be purified or separated was
added to the centrifuge using a funnel that was connected with a tube. When the
centrifuge was full enough, the lightest liquid would leave by one of the sides while the
heaviest compounds stayed inside the centrifuge until it was stopped.
!
33
!
34
5 RESULTS
5.1 Titration
Prior to the transesterification reaction, the titration of the oils should be done to calculate
the amount of catalyst which is necessary. During the lab trials, titrations with both
potassium hydroxide and sodium hydroxide were done, the results of both of them are
shown in table 5.1 and table 5.2.
Type of oil
Volume of 1g/L KOH
(mL)
Grams of KOH/L of oil
Grams of KOH/500 mL
of oil
Rapeseed 1
7.7
16.7
8.4
Rapeseed 2
4.1
13.1
6.6
Rapeseed 3
3.5
12.5
6.3
Sunflower
1.7
10.7
5.4
Hemp
18.3
27.3
13.7
Linseed
3.3
12.3
6.2
Table 5.1: Titration results when using KOH as a catalyst
Type of oil
Volume of 1g/L NaOH
(mL)
Grams of NaOH/L of oil
Grams of NaOH/500 mL
of oil
Rapeseed 2
2.8
6.3
3.2
Table 5.2: Titration results when using NaOH as a catalyst
Table 5.1 shows the results obtained when using potassium hydroxide as a catalyst, while
table 5.2 is for the sodium hydroxide. In the first case three different types of rapeseed oil
were tested and the second type was the one chosen to be the raw oil for all the
experiments when rapeseed oil was used as a reagent. The grams of catalyst for 500 mL
of oil are shown because this is the volume of oil that was used in all the experiments.
The difference between the three types of rapeseed oil is basically, that they were stored
in different containers and they had been obtained at different dates, so, the titration for
the three of them had to be done.
5.2 Biodiesel production
5.2.1 Influence of the catalyst
As it has been previously explained, the catalyst is one of the most important factors
affecting the reaction. The next sections will show the influence of different catalysts
and the way of using them when doing the transesterification reaction. All the reactions
were done at room temperature, which was approximately 21 ºC.
!
35
5.2.1.1 Amount of potassium hydroxide
Sample
Amount of
KOH (g)
Voil (mL)
Vmethanol
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol
(g)
Vbiodiesel
(mL)
Mbiodiesel
(g)
3:27 test
1
4.7
500
100
5
92
93.7
480
415.9
Not passed
2
6.2
500
100
5
92
91.3
495
425.6
Not passed
3
6.8
500
100
5
94
96.9
490
421.9
Passed
4
7.5
500
100
5
92
95.1
475
409.7
Passed
5
7.8
500
100
5
103
105.1
475
419.3
Passed
Table 5.3: Influence of the amount of potassium hydroxide in the production of biodiesel
Five different amounts of potassium hydroxide were tried, in all the cases the rest of
Glycerol volume (mL)
factors were the same. In table 5.3 it can be seen that only three out of five experiments
were successful, that is, passed the 3:27 test. This indicates that a minimum amount of
6.8 grams of KOH is necessary to obtain a complete reaction. Therefore, that amount
was decided to be the standard amount of potassium hydroxide when doing the
transesterification reaction with the sample 2 of rapeseed oil.
110.0
105.0
100.0
95.0
90.0
4.7
6.2
6.8
7.5
7.8
Amount of KOH (g)
Figure 5.1: Variation of the volume of glycerol produced depending on the amount of KOH
The volume of glycerol produced increases highly with the amount of catalyst used.
5.2.1.2 Amount of sodium hydroxide
Sample
Amount of
NaOH (g)
Voil (mL)
Vmethanol
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol
(g)
Vbiodiesel
(mL)
Mbiodiesel
(g)
3:27 test
1
3.2
500
100
5
79
80.4
485
418.8
Not
passed
2
3.5
500
100
5
86
88.4
470
410.8
Not
passed
3
4.0
500
100
5
90
85.9
480
414.7
Passed
Table 5.4: Influence of the amount of sodium hydroxide in the production of biodiesel
As in the previous case, different amounts were tested. When using sodium hydroxide
as a catalyst, only one of the samples passed the 3:27 test. In the other cases, the
reaction was not complete.
!
36
Glycerol volume (mL)
90
86
83
79
75
3.2
3.5
4.0
Amount of NaOH (g)
Figure 5.2: Variation of the volume of glycerol produced depending on the amount of NaOH
The higher the amount of sodium hydroxide used in the transesterification reaction, the
higher the volume of glycerol produced, that can also mean a lower biodiesel yield.
5.2.1.3 Not preparing the potassium methoxide previously
To find out whether it was possible to do the transesterification reaction without
preparing the methoxide previously, this was tried in one of the experiments, at room
temperature. The results of the experiments are displayed in table 5.5.
Sample
Amount of
KOH (g)
Voil (mL)
Vmethanol
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol
(g)
Vbiodiesel
(mL)
Mbiodiesel
(g)
3:27 test
1
6.8
500
100
6
93
96.8
480
419.8
Passed
Table 5.5: Results obtained when the potassium methoxide was not previously mixed
The reaction time is longer than usual due to some mixing difficulties that were
observed at the beginning of the reaction.
5.2.1.4 Adding the potassium hydroxide in two stages
As an attempt to save catalyst, the two-thirds method was tried at room temperature.
Two different amounts of catalyst were tried, 6.2 and 6.8 grams.
Sample
Amount of
KOH (g)
Voil (mL)
Vmethanol
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol
(g)
Vbiodiesel
(mL)
Mbiodiesel
3:27 test
(g)
1
6.2
500
100
4
80
85.1
490
425.6
Passed
2
6.8
500
100
4
90
95.2
485
417.6
Passed
Table 5.6: Results obtained when adding the potassium methoxide in two stages
Stage 1
Stage 2
Sample
Vmethoxide
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol (g)
Vmethoxide
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol (g)
1
66
2
56
60
34
2
24
25.1
2
66
2
61
64.1
34
2
29
31.1
Table 5.7: Volumes and masses of glycerol obtained
!
37
Both experiments were successful. The reaction time was a bit shorter than usual
because there was some sedimentation time between both reaction stages and it was
considered that four hours would be enough. It should also be mentioned that the result
of the solubility test was much worse than the result obtained when preparing the
potassium hydroxide previously.
5.2.1.5 Two stage acid-alkali reaction
When the amount of free fatty acids is too high, a two stage reaction is recommended.
First, an acid catalyst is used and then an alkali catalyst. This was done with two
different kinds of oils, one type of rapeseed oil and hemp oil. The titration results for
them were 16.7 and 27.3 grams of potassium hydroxide per litre of oil, respectively.
Sample
Type of oil
VH2SO4 (mL)
Vmethanol (mL)
Reaction time (h)
Titration result (mL)
1
Hemp
3
50
23
3.0
2
Rapeseed 1
1
50
23
1.2
Table 5.8: Results of the acid catalised reactions
After the reaction, which was done overnight with continuous stirring and at room
temperature, the titration of the products was done, obtaining low amounts of potassium
hydroxide. Therefore, the alkali catalysed reaction could be done. The results of the
second stage are shown in table 5.9.
Sample
Type of oil
Amount of
KOH (g)
Voil (mL)
Vmethanol Reaction Vglycerol Mglycerol Vbiodiesel Mbiodiesel
(mL)
time (h) (mL)
(g)
(mL)
(g)
1
Hemp
6
500
100
5
116
123.3
462
405.2
Passed
2
Rapeseed 1
5.1
500
50
5
100
100.8
410
361.3
Not passed
3:27 test
Table 5.9: Results obtained in the second stage of the acid-alkali catalysed reactions
In this case, there was an important difference between the two reactions, in the case of
hemp oil, 100 mL of methanol were used in the second stage, while only 50 mL were
used with the rapeseed oil. This was done to try whether or not it was possible to use
only 50 mL in the second stage because 50 more had already been used in the first
one. As it can be seen in the results, the product obtained from the rapeseed reaction is
not completely transesterified.
5.2.2 Influence of methanol
Methanol, with oil, is one of the reagents of the transesterification. The amount of
methanol used will lead to high variations in the results of the reaction. Moreover,
saving methanol means lower costs when producing biodiesel. Different amounts were
tried to find out the best option. All the reactions were done at room temperature.
!
38
Sample
Amount of
methanol (mL)
Voil (mL)
MKOH (g)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol Vbiodiesel Mbiodiesel
(g)
(mL)
(g)
1
60
500
6.8
5
104
103.7
420
372.1
Not passed
2
80
500
6.8
5
98
100.6
465
403.9
Not passed
3
100
500
6.8
5
94
96.9
490
421.9
Passed
3:27 test
Table 5.10: Influence of the amount of methanol in the production of biodiesel
Only when 100 mL of methanol was used, that is, 20% of the amount of rapeseed oil,
the reaction was complete. Furthermore, with low quantities of methanol, the separation
of the glycerol and biodiesel phases became complicated due to the high viscosity of
the glycerol.
There is another important factor in this case, the production of biodiesel. It can be seen
from the data that the yield of biodiesel decreases when the volume of methanol is
Biodiesel volume (mL)
lower.
490
470
450
430
410
60
80
100
Methanol volume (mL)
Figure 5.3: Variation of the volume of biodiesel produced depending on the amount of methanol
Glycerol density (g/mL)
A higher methanol volume in the transesterification reaction gives a higher biodiesel
yield, as it can be seen in figure 5.3.
1.040
1.025
1.010
0.995
0.980
60
80
100
Methanol volume (mL)
Figure 5.4: Variation of the density of glycerol depending on the volume of methanol
Finally, there is another important factor, the density of glycerol, that should not be
forgotten. The density is higher when higher amounts of methanol are used because the
separation of the phases is better, since less biodiesel is dissolved in the glycerol
phase.
!
39
5.2.3 Influence of the temperature
Since the objective of this thesis is to find a suitable method to produce biodiesel
without using a heat source, different reactions using heat were done to compare the
results of both options. In this part, the results of those reactions are shown.
Amount of
Voil (mL)
KOH (g)
Vmethanol Reaction
(mL)
time (h)
Vglycerol
(mL)
Mglycerol
(g)
Vbiodiesel
(mL)
5
94
96.9
490
421.9
Passed
100
5
106
108.3
460
397.5
Passed
100
5
132
132.8
395
344.1
Passed
Sample
T (ºC)
1
21 (room T)
6.8
500
100
2
40
6.8
500
3
60
6.8
500
Mbiodiesel
3:27 test
(g)
Table 5.11: Influence of the temperature on the transesterification reaction
First of all, it should be mentioned that all the trials passed the 3:27 test, therefore, the
Biodiesel volume (mL)
oil was fully reacted in all the cases. The results show clearly the difference in the yield
of biodiesel with the temperature when long reaction times ares used. With higher
temperature, higher glycerol yields and lower biodiesel yields are obtained.
490
460
430
400
370
room
40
60
Temperature (ºC)
Figure 5.5: Evolution of the volume of biodiesel with the temperature
In this experiment, the results of the solubility test have certain importance too. Those
results were better when the temperature was lower.
Since the amount of glycerol obtained at 60ºC was found to be too high, a new reaction
was started, with the difference, that, in this case, the reaction time was set to just an
hour.
Sample T (ºC)
1
60
Amount of
KOH (g)
Voil (mL)
6.8
500
Vmethanol Reaction
(mL)
time (h)
100
1
Vglycerol
(mL)
Mglycerol
(g)
Vbiodiesel
(mL)
83
87.1
480
Mbiodiesel
3:27 test
(g)
419.8
Passed
Table 5.12: Biodiesel production at 60ºC after 1 hour
The 3:27 test was passed, which indicates that the reaction was complete.
!
40
Another trial was done at low temperatures. Due to technical difficulties (it had to be
done outside), stirring could only be done for half an hour at the beginning of the
reaction and, then, for ten minutes in every hour. Since the results of this experiments
could not be compared with those of a reaction at room temperature with continuous
stirring, a trial at room temperature with the same stirring times was done. The results of
both tests are shown in table 5.13.
Sample
T (ºC)
Amount of
KOH (g)
Voil
(mL)
Vmethanol Reaction Vglycerol Mglycerol Vbiodiesel Mbiodiesel
(mL)
time (h) (mL)
(g)
(mL)
(g)
1
3
6.8
500
100
5.5
86
89.1
500
430.4
Not passed
2
21 (room T)
6.8
500
100
5.5
93
96.1
460
397.1
Passed
3:27 test
Table 5.13: Results of the experiments at low temperature
When the trial was done outside, at about 3ºC, the reaction was not complete because
the 3:27 test was not passed. However, the biodiesel obtained at room temperature
passed the test. The reaction time was longer than usual in an attempt to minimise the
effect of the short stirring time. It should be mentioned that the volume of biodiesel
obtained in the room temperature trial was higher than 460 mL, but, due to some
spilling, part of it was lost.
5.2.4 Experiments with different kinds of oils
To prove the validity of the method to produce biodiesel at room temperature, it was
also tried using other oils apart from rapeseed oil. Hemp was tried in the acid-alkali
method, while, sunflower and linseed were used with alkali catalysts.
Sample Type of oil
Amount of
Vmethanol
Voil (mL)
KOH (g)
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol Vbiodiesel Mbiodiesel
3:27 test
(g)
(mL)
(g)
1
Linseed
6.8
500
100
5
76
81.4
495
427.4
Passed
2
Sunflower
5.4
500
100
5
87
92.2
495
436.9
Passed
Table 5.14: Results of the transesterification reaction with linseed and sunflower oils
Both experiments were successful, with slight differences in the amount of glycerol
obtained. This could be due to the differences of viscosity and properties of the oils.
5.3 Soap titration
Soap tests were performed for the biodiesel samples that passed the 3:27 test and were
found to be significative due to different factors. The result of those tests is shown in the
table below. As mentioned in the experimental procedure, the quantity of soap in the
biodiesel was calculated with the formula shown in figure 5.6.
!
41
B ⋅ 0.1
Grams of soap / gram of sample =
B = mL 0.01 N HCl
W = g biodiesel
mol HCl
g
⋅ 320.56
l
mol soap
1000 ⋅W
Figure 5.6: Calculation of the grams of soap per gram of biodiesel [28]
Sample
VHCl 0.01 N (mL)
Biodiesel sample (g) Soap/biodiesel (g/g)
Room T
2.2
10
0.007
40 ºC
2.2
10
0.007
60 ºC
5.5
10
0.018
60 ºC (1h)
4.1
10
0.013
2/3 (6.2 g KOH)
6.9
10
0.022
2/3 (6.8 g KOH)
5.5
10
0.018
Sunflower
3.2
10
0.010
Linseed
2.9
10
0.009
Hemp
3.8
10
0.012
Table 5.15: Soap content of different biodiesel samples
The soap content varies widely depending on how the biodiesel was done, that is,
depending on the conditions of the reaction and, also, on the oil used to make biodiesel.
5.4 Cleaning biodiesel
In order to try the different biodiesel cleaning options, several biodiesel batches were
prepared, using the conditions that were found to be the best after all the experiments that
had been performed before. The data about those batches can be seen in table 5.16.
Sample
Amount of
KOH (g)
Voil (mL)
Vmethanol
(mL)
Reaction
time (h)
Vglycerol
(mL)
Mglycerol
(g)
Vbiodiesel
(mL)
Mbiodiesel
(g)
3:27 test
1
6.8
500
100
5
98
100.3
480
413.2
Passed
2
6.8
500
100
5
94
96.9
490
421.9
Passed
3
6.8
500
100
5
92
96.5
490
424.2
Passed
4
6.8
500
100
5
91
95.0
485
423.2
Passed
5
6.8
500
100
5
93
96.3
480
414.3
Passed
6
6.8
500
100
5
99
101.8
460
406.3
Passed
7
6.8
500
100
5
99
101.3
460
403.9
Passed
8
6.8
500
100
5
94
96.9
480
413.9
Passed
Table 5.16: Biodiesel batches for cleaning
Soap titrations were done both before and after the cleaning. The results are presented
separately, on the one hand the dry cleaning and on the other hand the water cleaning.
!
42
Cleaning
system
Amount of
cleaning
product (g)
Magnesol 1
7.5
492.5
3.5
0.011
0.5
0.002
85.7
Magnesol 2
7.5
492.5
5.5
0.018
1.8
0.006
67.3
D-Sol
2.5
497.5
3.5
0.011
1.1
0.004
68.6
Aerogel 250
7.5
492.5
3.5
0.011
0.7
0.002
80.0
Aerogel
7.5
492.5
3.5
0.011
0.8
0.003
77.1
Biodiesel Soap titration Soap/biodiesel Soap titration Soap/biodiesel
%
(g)
before (mL)
before (g/g)
after (mL) after (g/g) (mL) reduction
Table 5.17: Dry cleaning results
Magnesol 1 and 2 refers to the same type of product, but, due to an error, in the first
filtration two filter papers were used instead of one, so the experiment was repeated.
Otherwise, Aerogel 250 and Aerogel are different products and more information about
them can be found in the Annex V.
Cleaning
system
Water
bubbling
Magnesol
1+ water
bubbling
Number
of
stages
3
4
3
Duration of
stages (h)
Soap
Soap/biodiesel Soap titration Soap/biodiesel % reduction
titration
before (g/g)
after (mL)
after (g/g) (mL)
soap
before (mL)
1-3-1 1-3-1-94
5.5
0.018
1-72-1
5.5
0.018
3
4
3
4
3
4
2.0
0.7
0.006
0.002
63.6
87.3
0.1
0.000
98.2
Table 5.18: Water cleaning results
For the first water cleaned sample, the soap titration was done twice, one after 5 hours of
cleaning (3 changes of water) and the other after a new step which took 4 days. The
biodiesel cleaned with Magnesol was also cleaned with water afterwards in three steps (1
hour, 72 hours, 1 hour).
5.5 Using the centrifuge
Six different tests were done using the centrifuge, some with just one component and
others with two-phase liquids.
Components
Composition
Result
Sunflower oil
-
Impurities were extractred
Biodiesel + glycerol
50:50
No separation of the liquids
Biodiesel + water
90:10
No separation of the liquids
Raw biodiesel
-
No impurities extracted
Raw rapeseed oil
-
No impurities extracted
Raw glycerol
-
No impurities extracted
Table 5.19: Using the centrifuge
!
43
!
44
6 DISCUSSION
6.1 Titration
The results of the titration showed clear variations on the amounts of free fatty acids of the
different oils. This may be caused by the composition of the oil, but also because of long
storage times, which usually lead to decomposition of the triglycerides and, thus, more
content of free fatty acids.
grams of KOH/L of oil
30.0
22.5
15.0
7.5
0
Rapeseed 1
Sunflower
Rapeseed 2
Hemp
Rapeseed 3
Linseed
Figure 6.1: Comparison of the titration results of the different oils
6.2 Biodiesel production
6.2.1 Reaction time
Even if specific experiments to determine the most appropriate reaction time were not
performed, it was determined that 5 hours was the best value for most of the reaction
times. This is because it is enough time for the reaction to be complete. The only
limitation imposed by the reaction time is that, in case it is not long enough, the reaction
will not be complete. Therefore, allowing a long enough time will avoid any problems
and ensure a complete reaction.
6.2.2 Influence of the catalyst
6.2.2.1 Amount of potassium hydroxide
Several difficulties were found in the first attempts to obtain a fully reacted biodiesel.
Therefore, five different amounts of catalyst were tried. This indicates that the titration
results may not always be completely correct. However, it can be used as a starting
point. Especially if large volumes of biodiesel are to be produced at a time, it is
recommended to try the reaction parameters first with small batches to ensure the fully
completion of the reaction. Another important factor is that the production of glycerol
!
45
increases with the amount of catalyst. Because of this, the biodiesel yield may be
affected.
Obtaining a pass in the 3:27 test meant that the objective of this thesis was fulfilled, that
is, biodiesel can be produced at room temperature. These first trials were helpful to
determine important factors for the next experiment, like the reaction time, which was
decided to be five hours, the continuous stirring and, of course, the amount of
potassium hydroxide to use.
6.2.2.2 Amount of sodium hydroxide
Sodium hydroxide, as well as potassium hydroxide, is one of the most widely used
catalysts when producing biodiesel. Sodium hydroxide, compared to potassium
Grams of catalyst per liter of oil
hydroxide, means using lower amounts of catalyst. However, it is more difficult to
dissolve because of its shape (potassium hydroxide is prepared as flakes, while sodium
hydroxide is prepared as lentils) and it is also more expensive. Therefore, it was
decided that potassium hydroxide would be the catalyst used for all the reactions.
KOH
NaOH
14.0
10.5
7.0
3.5
0
Figure 6.2: Comparison between KOH and NaOH
6.2.2.3 Not preparing the potassium methoxide previously
Since the 3:27 test was passed, it can be said that there is not a necessity to prepare
the methoxide previous to the transesterification reaction. However, it was also
observed that it took longer to start the reaction in this case, because of the increased
difficulty to dissolve the flakes of potassium hydroxide. This is why the reaction time
chosen was longer than in the previous cases, to allow the reaction to be complete. It
can be observed from the results that the products obtained are similar to what is
obtained with previous mixing.
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46
Volume (mL)
500
375
250
125
0
Glycerol
Previous mixing
Biodiesel
Without previous mixing
Figure 6.3: Comparison of volumes with previous mixing of the methoxide and without it
500.0
Mass (g)
375.0
250.0
125.0
0
Glycerol
Previous mixing
Biodiesel
Without previous mixing
Figure 6.4: Comparison of masses with previous mixing of the methoxide and without it
As it can be seen in figures 6.3 and 6.4, both volumes and masses are almost equal
when previous preparation of the methoxide was done and when it was not done. This
means that the reaction could be done without preparing the methoxide previously, at
least, when using potassium hydroxide as a catalyst. However, this was done with 500
mL of oil, it may imply more difficulties when doing it with big volumes because of the
complications with the stirring.
6.2.2.4 Adding the potassium hydroxide in two stages
This experiment was successful because the 3:27 test was passed when using both 6.2
and 6.8 grams of potassium hydroxide. It is important to note that when adding all the
potassium methoxide at the same time and using 6.2 grams of potassium hydroxide,
the 3:27 test was not passed. However, in this case, the test was passed, so catalyst
could be saved using this method. On the other hand, the result of the solubility test
when the catalyst was added in two stages was unsatisfactory, because it was much
worse than the result obtained in other experiments.
Apart from that, this method implies more handling than when adding all the potassium
methoxide at the same time, because there are two sedimentation stages instead of
!
47
one. Since the purpose of this thesis is to find an easy way to produce biodiesel, this
option was dismissed. However, it could be used with satisfactory results and a lower
catalyst consumption.
6.2.2.5 Two stage acid-alkali reaction
Only one of the acid-alkali catalysed reactions was successful. This is probably because
of the fact that only 50 mL of methanol was used in the second stage of the rapeseed
reaction. Methanol, as explained previously, is essential for the reaction to be complete.
The lack of methanol has two consequences, the first being an incomplete reaction and
the second a low biodiesel yield. At the same time, when excess methanol is used, the
glycerol volume obtained is higher than usual. Those phenomena are shown in figures
6.5 and 6.6, the first shows the volumes of methanol and the second the volumes of
methanol. The data is about the products of the two acid-alkali catalysed reactions and
of the potassium hydroxide catalysed reaction with standard conditions.
Volume of glycerol (mL)
Hemp oil
Rapeseed oil acid
Rapeseed oil alkali
120
90
60
30
0
Volume of biodiesel (mL)
Figure 6.5: Comparison of the volumes of glycerol obtained
490.0
467.5
445.0
422.5
400.0
Hemp oil
Rapeseed oil acid
Rapeseed oil alkali
Figure 6.6: Comparison of the volumes of biodiesel obtained
6.2.3 Influence of methanol
The methanol experiments worked only when 20% methanol in volume was used for
the reaction, when using lower volumes, the 3:27 test was not passed, that is, the
reaction was incomplete. Nevertheless, not only was the reaction incomplete when
!
48
using low volumes of methanol, the glycerol obtained was also very viscous, making the
sedimentation and separation steps complicated.
The reasons exposed above may indicate the necessity of using enough methanol on
the reaction. However, methanol has several disadvantages when used in excess,
because it stays in both biodiesel and glycerol phases of the products. Those products
have to be cleaned of methanol, because it is a dangerous product that can pollute the
soil, water, etc. Apart from that, biodiesel standards set maximum methanol amounts in
its composition and methanol should also be removed before using dry cleaning
products.
To sum up, a decision has to be taken with methanol. There are basically two options,
the first of them is using excess methanol for the reaction, which will mean having a
completely reacted biodiesel and having to remove the methanol from both biodiesel
and glycerol phases. The other possible option is using lower methanol volumes, which
will mean a not completely reacted product and more difficulties in the separation, but
methanol will not have to be removed from the products. The first option appears to be
more suitable when standardised biodiesel is wanted and the product is going to be
sold, while the second is more appropriate when biodiesel for self consume is produced
and it does not matter having unreacted oil in the biodiesel and not complying with the
standards.
6.2.4 Influence of the temperature
The purpose of the different temperatures trials was to find out whether good results
could be obtained at low temperatures and, also, find out the limits of the reaction. In
fact, looking at the results, it could be determined that the reaction does not work when
the temperatures are too low (3 ºC). It was explained in the results section that the
stirring was not continuous in that case, but, since the experiment was repeated with
the same stirring periods but at room temperature and the reaction was complete, it can
be concluded that the stirring is not the determining factor. Indeed, the temperature is
the controlling parameter.
There is another issue that should be carefully looked into when discussing the effects
of the temperature. It is the production of glycerol (and the biodiesel production which is
related to it), which varies highly with the temperature reaction. Figure 6.7 shows the
different glycerol volumes which were obtained at different temperatures. The amount of
methanol is higher when the reaction temperature is increasing. Moreover, the volume
obtained at 60 ºC seems to be too high.
!
49
Glycerol volume (mL)
140
105
70
35
0
3
21 (room T)
40
60
Temperature (ºC)
Figure 6.7: Influence of the temperature on the glycerol volume
One of the options that was considered to be a reason that could explain the high
glycerol volumes was the reaction time. The reaction times found in the literature when
temperatures around 60 ºC were used, was usually an hour or lower. In this case,
however, the reaction time used was five hours. Therefore, the reaction was done at 60
ºC for one hour and a much lower volume of glycerol was obtained, as shown in figure
6.8.
Glycerol volume (mL)
140
105
70
35
0
60 ºC, 5 hours
60 ºC, 1 hour
Figure 6.8: Glycerol volumes after 1 hour and 5 hours reacting at 60 ºC
Since the reaction was complete in both cases, the long reaction time seemed to be an
explanation. However, there were another two issues that had to be explained yet, on
the one hand, the glycerol obtained at 60 ºC is much more viscous than usual and the
glycerol volume seemed to be too high to be just glycerol, some other compounds had
to be there.
Explanation for both facts can be found. The glycerol was very viscous because of the
evaporation of methanol, which, as explained previously, is necessary to obtain a less
viscous glycerol. Methanol may have evaporated due to the high temperature. Besides,
the mono and diglycerides seemed to dissolve in the glycerol phase, which would
explain the very high glycerol volumes.
!
50
A trial with pure glycerol and raw biodiesel was done to determine the validity of this
theory, the results are shown in table 6.1:
Temperature
Vbiodiesel (mL) Vglycerol (mL)
(ºC)
60
400
100
Reaction
time (h)
Vglycerol (mL)
Mglycerol (g)
5
88
106.9
Vbiodiesel (mL) Mbiodiesel (g)
380
340.1
Table 6.1: Biodiesel and pure glycerol results
The volumes of both glycerol and biodiesel were lower after 5 hours, this may be partly
explained by the evaporation of methanol, but there probably is also some dissolution of
the mono and diglycerols from the biodiesel in the glycerol phase. In fact, glycerol, that
at the beginning of the experiment had no colour, had certain yellow coloration when it
finished.
6.2.5 Experiments with different kinds of oils
The fact that the transesterification reaction worked for four different kinds of oils at
room temperature confirms the validity of the method. The variations in biodiesel and
glycerol outputs can be explained because of the use of different methods (hemp oil
was transesterified using the acid-alkali method, the other oils only used alkali catalyst)
and because of the different properties of those oils. In figure 6.9, the biodiesel volumes
obtained with different kinds of oils is displayed.
Biodiesel volume (mL)
500
375
250
125
0
Rapeseed
Linseed
Sunflower
Hemp
Figure 6.9: Biodiesel production from different oil sources
The lower volume obtained with hemp oil may be due to the fact that acid-alkali
transesterification was used. In the other cases, the obtained biodiesel volume is almost
the same.
!
51
6.3 Soap titration
Room T
60 ºC (1h)
Sunflower
40 ºC
2/3 (6.2 g KOH)
Linseed
60 ºC
2/3 (6.8 g KOH)
Hemp
Soap biodiesel (g/g)
0.030
0.023
0.015
0.008
0
Figure 6.10: Soap grams per gram of biodesel
The amount of soap varies widely depending on how the biodiesel was done. Both
experiments that were done using the 2/3 method, as well the experiments done at 60 ºC
produce biodiesel with high soap amounts. This is consistent with the observations made
in the solubility tests, which were much worse in those cases. The reason for the
difference in the production of soaps is unknown. Finally, it should be noted that biodiesel
produced at room temperature obtains the best result in the soap titration with biodiesel
produced at 40 ºC.
6.4 Cleaning biodiesel
Four different dry products were tried, as well as water bubbling. The best results were
obtained for water bubbling and Magnesol. However, the water bubbling cleaning took
almost five days. Time is a powerful disadvantage of water bubbling when comparing it
with other methods, because dry cleaning takes usually less than one hour, just 20
minutes for mixing and then some extra time for filtering the product. On the other hand,
dry products are more expensive than water. Therefore, depending on different factors, the
most suitable method will have to be decided for every manufacturers conditions.
!
52
% Reduction soap
100.0
75.0
50.0
25.0
0
Magnesol 1
D-Sol
Aerogel 2
Water bubbling 4 steps
Magnesol 2
Aerogel 1
Water bubbling 3 steps
Magnesol 1+ water bubbling
Figure 6.11: Soap amount reduction with different products
As mentioned, the best result is obtained for the combination of Magnesol and water
bubbling, in that case 98% of the soap is removed. Water bubbling with four steps and
Magnesol are also good options, but, in the case of Magnesol, two filtering papers were
used, so this results are not significative.
6.5 Using the centrifuge
Five different trials were performed with the centrifuge and only one of them had a
satisfactory result. It worked when using it to remove impurities from a raw sunflower oil.
Consequently, its use is recommended when impurities from oils have to be removed, but
different systems should be used to remove water from both biodiesel and oil and to
separate glycerol and biodiesel, because it does not work with the centrifuge.
6.6 Methanol
During the making of the thesis, methanol has not been taken into account as a possible
hazard in the products. This is an important issue, because several difficulties appear
when methanol is present in any mixture. Biodiesel standards set a maximum methanol
amount, the manufacturers of dry cleaning products recommend its removal before using
their products and it has to be removed if glycerol has to be purified or if it is going to be
used to produce soaps.
The reasons stated above show clearly how important the methanol removal is, but,
methanol has a good property which facilitates this process, it is a very volatile product, so
it will evaporate from biodiesel if left in contact with air. Methanol spilling on soils is a
serious environmental risk, but its evaporation into air does not have any disadvantages.
!
53
When doing the experimental procedure for this paper, methanol was ignored, in fact, dry
cleaning was done without removing it and it worked. Actually, there would probably not be
too many inconveniences if using the biodiesel obtained without any methanol removal
stages, but, it could always be left in contact with air for some time, just to make sure that
no problems will appear.
A simple test was done with biodiesel that had been left in contact with air for some time (it
was a mixture of different batches, so the time was different for each of them), the
biodiesel was heated up to 120 ºC for two hours. It was weighed both before and after the
heating and no significative reduction of weight was noticed, as shown in table 6.2.
Vbiodiesel (mL)
Wbiodiesel (g)
Before heating
305
264.4
After heating
315
262.5
Figure 6.2: Methanol removal
To sum up, in this case methanol was not taken into account because it is not important for
the purpose of the thesis, but, when producing biodiesel in big batches, its presence
should be considered and a process to do so will probably be necessary.
!
54
7 CONCLUSION
First of all, it can be stated that the purpose of the thesis was fulfilled, a method for
producing biodiesel at room temperature was developed and it seems to be valid, since
complete transesterification of the oil is achieved. Moreover, the procedure has been tried
with different oils and catalysts and worked in all cases.
Nevertheless, there are some limitations that may change the outcome if considered.
Firstly, the fact that a detailed analysis of the biodiesel obtained could not be done
because of the lack of a gas chromatography system. Because of this, simple analyses as
the 3:27 test and soap titrations are the only proof of the validity of this method.
Another issue that deserves to be focused on is methanol. It has been disregarded during
the experimental procedure because it is not a key question in this case, but it is when
producing biodiesel in big quantities. Therefore, it should be considered when producing
biodiesel that is going to be used by oneself or that is going to be sold.
As an extension to this thesis, another trial to produce biodiesel is going to be done. The
difference between both studies is that in this new case, the volumes are going to be 1000
times larger. That is, instead of producing batches of biodiesel of 500 mL, batches of 500
litres are going to be obtained. In fact, this thesis is the pilot trial of the new system. It is
right now being constructed in the same place where this thesis took place, the Faculty of
Engineering and Sustainable Development, but it is not finished and it has not been tried
yet. With this new development, it will be possible to find out whether biodiesel can also be
produced without any heat in large batches, or if, on the contrary, that system only works
in a lab scale. In the case that, as it is hoped, the large scale works, this method could be
used by farmers to produce their own biodiesel, due to its simplicity and low cost. Using
this system instead of a heated system means less expenditure on the equipment,
because it is easier to find materials. It also implies less risks, since the use of heat is
avoided. Moreover, to produce biodiesel in this way does not imply a big necessity to
control the system, because nothing would happen if the reaction time is longer or if the
raw biodiesel is left to stand for a while.
I believe that biodiesel may help to make our world more sustainable, but some conditions
should be met. It is useless producing biodiesel in big factories, using oil that has been
produced in another continent and then selling the biodiesel all over the world. Biodiesel is
helpful when it is produced locally, using seeds that are adapted to the climate of the area,
producing the oil next to the place where the crops are grown and, if possible, producing
!
55
the biodiesel in the same place, using a simple and cheap system. In this way, biodiesel
will be a sustainable fuel and it may even help to developing countries.
Finally, this thesis is not complete if the issue of biodiesel versus food is not mentioned. I
do believe that food is more important than fuels, as a matter of fact, human beings can
live without cars but cannot live without eating. However, I think that the issue is not so
simple. I understand that when producing the biodiesel in an industrial way, it is not
sustainable and, many times, this can increase the price of different types of food.
Nevertheless, since I believe in the production of biodiesel in a sustainable way and
locally, I do not think that this would affect the prices of food. Mainly because farmers
producing biodiesel would do so because they have soil available to grow these crops
and, many times, the biodiesel will be for their own consumption. Besides, it should not be
forgotten that biodiesel can be produced using waste vegetable oil, which does not
compete with any kind of food to be attained. Therefore, I do understand the concerns of
some people about biodiesel, but I think that, if produced in a sensible way, it can be
helpful, but, of course, it will not be the solution to all our problems.
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56
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58
ANNEX I: PROPERTIES OF VEGETABLE OILS
Fatty acid composition (wt %)
12:0
14:0
14:1
16:0
16:1
18:0
20:0
20:1
22:0
24:0
18:1
22:1
18:2
18:3
18:4
6:0, 8:0, 10:0 and others
Cottonseed
-
0
-
28
-
1
0
-
0
0
13
0
58
0
-
-
Tobacco
-
0.09
-
10.96
0.2
3.34
-
-
-
-
14.54
-
69.49
0.69
-
0.69
Rapeseed
-
0
-
3
-
1
0
-
0
0
64
0
22
8
-
-
Safflower
-
0
-
9
-
2
0
-
0
0
12
0
78
0
-
-
Sunflower
-
0
-
6
-
3
0
-
0
0
17
0
74
0
-
-
Sesame
-
0
-
13
-
4
0
-
0
0
53
0
30
0
-
-
Lindseed
-
0
-
5
-
3
0
-
0
0
20
0
18
55
-
-
Palm tree
-
-
35
-
7
-
-
-
-
44
-
14
-
-
-
Corn
-
0
-
12
-
2
Tr
-
0
0
25
0
6
Tr
-
-
Tallow
-
-
-
23.3
0.1
19.3
-
-
-
-
42.4
-
2.9
0.9
2.9
-
Soya bean
-
-
-
14
-
4
-
-
-
-
24
-
52
-
6
-
Peanut
-
0
-
11
-
2
1
-
2
1
48
0
32
1
-
-
Coconut
48.8
19.9
-
7.8
0.1
3.0
-
-
-
4.4
-
0.8
0
65.7
8,9, 6,2
0.70
0.00
14.26
1.43
8.23
0.33
0.48
-
43.34
-
26.25
2.51
0.47
-
Vegetable oil
Yellow grease
-
Vegetable
oil
Kinematic viscosity
at 38ºC (mm2/s)
Cetane No.
(ºC)
Heating Value
(MJ/kg)
Cloud Point
(ºC)
Pour Point
(ºC)
Flash Point
(ºC)
Density
(kg/l)
Carbon residue
(wt %)
Corn
34.9
37.6
39.5
-1.1
-40
277
0.9095
0.24
Cottonseed
33.5
41.8
39.5
1.7
-15
234
0.9148
0.24
Crambe
53.6
44.6
40.5
10.0
-12.2
274
0.9048
0.23
Linseed
27.2
34.6
39.2
1.7
-15.0
241
0.9236
0.22
Peanut
39.6
41.8
39.8
12.8
-6.7
271
0.9026
0.24
Rapeseed
37.0
37.6
39.7
-3.9
-31.7
246
0.9115
0.30
Safflower
31.3
41.3
39.5
18.3
-6.7
260
0.9144
0.25
Sesame
35.5
40.2
39.3
-3.9
-9.4
260
0.9133
0.24
Soya bean
32.6
37.9
39.6
-3.9
-12.2
254
0.9138
0.25
Sunflower
33.9
37.1
39.6
7.2
-15.0
274
0.9161
0.27
Palm
39.6
42.0
-
31.0
-
267
0.9180
0.23
Babassu
30.3
38.0
-
20.0
-
150
0.9460
-
Diesel
3.06
50
43.8
-
-16
76
0.855
-
Source: S.P. Singh, Dipti Singh, Biodiesel production through the use of different sources and characterization of oils and their esters as the substitute of diesel: A
review, Renewable and Sustainable Energy Reviews 14 (2010), 200-216.
ANNEX II: BIODIESEL STANDARDS
1.European Standard for Biodiesel: EN 14214
Limits
Property
Testing method
Unit
Min
Ester content
Max
EN 14103
96.5
% (m/m)
EN ISO 3675
860
900
kg/m3
EN ISO 3104, ISO 3105
3.5
5.0
mm2/s
Flash point
EN ISO 3679
120
Sulphur content
EN ISO 20846
EN ISO 20884
10.0
mg/kg
Carbon residue (on 10% distillation residue)
EN ISO 10370
0.3
% (m/m)
Cetane number
EN ISO 5165
ISO 3987
0.02
% (m/m)
EN ISO 12937
500
mg/kg
EN 12662
24
mg/kg
Density at 15ºC
EN ISO 12185
Viscosity at 40ºC
Sulphated ash content
Water content
Total contamination
Copper strip corrosion (3h at 50º C)
ºC
51
EN ISO 2160
1
Oxidation stability, 110ºC
EN 14112
6.0
Acid value
EN 14104
0.5
mg KOH/kg
Iodine value
EN 14111
120
g iodine/100g
Linolic acid methyl ester
EN 14103
12
% (m/m)
1
% (m/m)
Fatty acid methyl esters (>=4 double bonds)
h
Methanol content
EN 14110
0.20
% (m/m)
Monoglyceride content
EN 14105
0.80
% (m/m)
Diglyceride content
EN 14105
0.20
% (m/m)
Triglyceride content
EN 14105
0.20
% (m/m)
Free glycerol
EN 14105
EN 14106
0.02
% (m/m)
Total glycerol
EN 14105
0.25
% (m/m)
EN 14108, EN 14109
5.0
mg/kg
prEN 14538
5.0
mg/kg
Alkaline metals (Na+K)
Alkaline earth metals (Ca+Mg)
Limits
Property
Testing method
Unit
Min
Phosphorus content
EN 14107
Max
10.0
mg/kg
Source: BASF Group
2.Specification for Biodiesel (B100) - ASTM D6751 - 08
Property
ASTM Method
Limits
Units
EN 14538
5 maximum
ppm (ug/g)
D 93
93 maximum
ºC
EN 14110
0.2 maximum
% volume
D 93
130 minimum
ºC
Water & Sediment
D 2709
0.05 maximum
% volume
Kinematic Viscosity, 40 ºC
D 445
1.9-6.0
mm2/s
Sulphated ash
D 874
0.02 maximum
% mass
S 15 Grade
D 5453
0.0015 max. (15)
% mass (ppm)
S 100 Grade
D 5453
0.05 max. (500)
% mass (ppm)
Copper Strip Corrosion
D 130
No. 3 maximum
Cetane
D 613
47 minimum
Cloud Point
D 2500
report
ºC
Carbon Residue 100% sample
D 4530
0.05 maximum
% mass
Acid Number
D 664
0.50 maximum
mg KOH/g
Free Glycerin
D 6584
0.020 maximum
% mass
Total Glycerin
D 6584
0.240 maximum
% mass
Phosphorus Content
D 4951
0.001 maximum
% mass
Distillation, T90AET
D 1160
360 maximum
ºC
Sodium/Potassium, combined
EN 14538
5 maximum
ppm
Oxidation Stability
EN 14112
3 minimum
hours
Cold Soak Filtration
Annex to D6751
360 maximum
seconds
For use in temperatures below -12 ºC
Annex to D6751
200 maximum
seconds
Calcium & Magnesium, combined
Flash Point (closed cup)
Alcohol Control (One of the following must be met)
1. Methanol Content
2. Flash Point
Sulphur
Source: the National Biodiesel Board
ANNEX III: LABORATORY EQUIPMENT
In the table the pictures and names of all the laboratory equipment which was used during
the project can be seen:
Erlenmeyer [1]
Beaker [2]
Weight balance [3]
Magnetic stirrer [4]
Pipette bulb [5]
Pipette [6]
Burette [7]
Separatory funnel [8]
Graduated cylinder [9]
Volumetric flask [10]
Kitasato flask [11]
Büchner funnel [12]
Filter paper [13]
Vacuum pump [14]
Sources:
[1] Wikipedia, Emil Erlenmeyer, http://en.wikipedia.org/wiki/File:Erlenmeyer_flask.jpg,
Access 2010-06-16.
[2] Supplierlist, Quartz crystals, http://www.supplierlist.com/wholesalequartz_crystals-7032.htm, Access 2010-06-16.
[3] PCE, http://www.pce-group-europe.com/espanol/product_info.php/info/p5375_Balanzacompacta-PCE-BSH-10000.html, Access 2010-06-16.
[4] Direct Industry, Stuart Equipment, http://www.directindustry.com/prod/stuart-equipment/
laboratory-hot-plate-magnetic-stirrer-63431-410177.html, Access 2010-06-16.
[5] Indigo, Pipet Bulbs-Pipetters Discontinued, http://www.indigo.com/science-supplies/
gph-science-supply/pipet-bulbs.html, Access 2010-06-16.
[6] Volumetric Aparatuses, Pipette, http://vet.kku.ac.th/physio/labbiochem/16/pipettetype2.html, Access 2010-06-16.
[7] B & B Performance Products, http://www.stefs.com/bandb/products/productpages/
toolsccburetstand.htm, Access 2010-06-16.
[8] Carl Roth, Labordedarf, http://www.carl-roth.de/catalogue/catalogue.do?
act=showBookmark&favOid=00000000000010c600020023&lang=de-de&catId=DE,
Access 2010-06-26.
[9] Imalab eirl, http://www.imalabeirl.com/catalogo/vidrio3.htm, Access 2010-06-26.
[10] Volumetric flask, http://commons.wikimedia.org/wiki/File:Volumetric_flask_hg.jpg,
Access 2010-06-26.
[11] Camlab, Büchner Flasks, http://www.camlab.co.uk/item.asp?
itemid=36629&categoryid=1254&key=&letter=&browsecategoryid=307, Access
2010-06-26.
[12] Buchner funnel, http://commons.wikimedia.org/wiki/File:Buchner_funnel.jpg, Access
2010-06-26.
[13] Hangzhou Special Paper Industry Co., Ltd., http://special-paper.en.made-inchina.com/product/hbeEpIGVgJkO/China-Chemical-Analysis-Filter-Paper.html, Access
2010-06-26.
[14] Labolan, Water Jet Vacuum Pump, http://www.labolan.es/detalles-producto.php?
idarea=18&p=1547&lang=en, Access 2010-06-26.
ANNEX IV: AIR FLOW MACHINE
For the production of air bubbles in the water cleaning part an air flow machine is needed.
For this thesis a ʻSuperFish AirFlow 4ʼ was used, its main characteristics are:
- 4 outputs to connect to airstones, filters etc.
- Air flow rate of 10 L/min
- Adjustable air flow
- Low power usage of 10 watts
- Low noise
ANNEX V: DRY CLEANING PRODUCTS
1.Magnesol
Magnesol is a synthetic magnesium silicate adsorbent, which is used as an adsorbent filter
aid. It ensures biodiesel quality by removed contaminants that can be found within the
methyl esters. It is manufactured by The Dallas Group of America. It is composed by
magnesium silicate in a 97%. Different articles and the material safety data sheet for
Magnesol can be found in the next pages.
2.D-Sol
As well as Magnesol, D-Sol is manufactured by The Dallas Group of America, it is used in
the same way as Magnesol, the main difference between them is their composition.
Magnesol is composed by magnesium silicate (97% minimum), while D-Sol is composed
in a 70% by magnesium silicate and the rest 30% is a component B, which is secret. In the
next pages, the material safety data for D-Sol and more information about it can be found.
3.Aerogel
Svenska Aerogel AB has developed an aerogel-like silicate material which has the
potential to be used as a generic adsorbent. The route for making the aerogel-like
adsorbent involves the precipitation of silica using alkali silicates and certain bi- and
trivalent metal ions. In many respects, the precipitated silica material shows great
similarities with the classic silica aerogel invented already in the 1930ʼs but involves a less
complicated route of processing, higher flexibility and the use of cheaper feedstock
chemicals.
Depending on the application the material can be made as a filler material with a typical
size range of 5 – 75μm or as coarser aggregates or granules having a characteristic size
of up to 10mm. The specific surface area (BET-area) is typically 400m2/g. The bulk density
of granules as well as filler is typically less than 0.40kg/m3.
The substrate material is environmentally friendly and consists solely of benign chemicals
and common elements such as Si, Ca and Mg.
Two different materials were used in the biodiesel trials, one of them is a spray dried
magnesium silicate material which has a particle range of 5-75 micrometers. The other
material is a calcium magnesium (35/65) silicate impregnated with 8% potassium
hydroxide and a particle range smaller than 250 micrometers.
Quality Comparison Summary
• SAVES TIME…
Purify biodiesel in
minutes, not hours
and with no messy
emulsions.
• SAVES ENERGY…
No drying required.
• SAVES CAPITAL…
No expensive centrifuges, dryers, and
no large settling tanks.
TM
• DRY WASH …
D-SOL adsorbent
technology requires
no wash water and
produces no waste
water.
Magnesol D-SOL is the first in Dry WashTM technology…
For more information, contact us today!
RAPESEED METHYL ESTERS
SPECIFICATIONS
ASTM D6751 EN 14214
Parameter
Soap, mg/kg
None
None
Free Glycerin, %
0.020 max
Total Glycerin, %
Initial
Sample
SOYBEAN METHYL ESTERS
Washed 0.5% D-SOL Initial
& Dried
D60
Sample
Washed 0.5% D-SOL
& Dried
D60
YELLOW GREASE METHYL ESTERS
Initial
Washed 1.5% D-SOL
Sample And Dried
D60
637
30
0
651
13
0
1900
91
0
0.020 max
0.053
0.000
0.005
0.033
0.002
0.000
0.063
0.037
0.002
0.240 max
0.250 max
0.217
0.162
0.162
0.209
0.196
0.186
0.220
0.185
0.143
Flash Point, °C
130 min
120 min
90
130
140
80
143
150
100
158
155
Metals I Na+K, mg/kg
5.0 max
5.0 max
53
3
0
61
5
0
67
3
0
Metals II Mg+Ca, mg/kg
5.0 max
5.0 max
6
5
0
4
0
0
8
0
0
Oxidation Stability @ 110°C, hours
3.0 min
6.0 min
0.61
0.65
2.25
0.5
0.6
3.7
0.5
0.6
4.3
Water, mg/kg
500 max
500 max
400
350
378
1000
150
300
7000
600
50
Sulfated Ash, mass %
0.020 max
0.020 max
0.056
0.002
0.000
0.060
0.005
0.000
0.08
0.010
0.002
Methanol Content, %
None
0.2 max
0.19
0.015
0.009
0.15
0.001
0.011
0.116
0.001
0.002
PHONE
[1] 812-283-6675 Ext. 5
EMAIL
[email protected]
WEB
www.dallasgrp.com
0705I205
PROCESS
Adsorbing
g It All
With a solid track record in oleo-chemical purification, The Dallas Group has
entered the biodiesel industry with a synthetic magnesium silicate adsorbent that
has changed the way some producers clean up their methyl esters.
By Tom Bryan
T
he Dallas Group of America Inc.,
a recognized leader in oleo-chemical purification technology, is
arguably the only U.S. company actively
marketing a commercial product for the
adsorptive purification of biodiesel. The
company’s synthetic magnesium silicate
adsorbent, sold under the trademarked
name Magnesol, is an “adsorbent filter
aid” that ensures biodiesel quality by
removing contaminants within methyl
esters. Subsequently, the removal of contaminants enables biodiesel producers to
guarantee that the fuel they produce meets
ASTM D-6751 specifications and other
industry standards.
The Dallas Group broke into the
North American biodiesel market with
Magnesol only recently, but according to
one producer, the adsorbent could be “a
cure-all for most process upsets and impurity problems” that occur during biodiesel
production. Multiple customers nationwide in the edible oils industry are already
using the product. Bryan Bertram, director of industrial sales with The Dallas
Group, believes the U.S. biodiesel market
represents one of the next big opportuni- impurities,” he told Biodiesel Magazine.
ties for the product line. In an interview “And due to the resulting effluent water, it
with Biodiesel Magazine, Bertram, along gives cause for environmental concerns.”
With Magnesol, the water-wash step
with Chris Abrams, business development
manager, and Brian Cooke, product devel- can be eliminated, and so can the liquid
opment specialist, discussed the compa- separation and drying of biodiesel. “It can
ny’s ongoing efforts with Magnesol. also replace other methods of removing
Bertram said the product increases the chlorophyll, metals, and color from
oxidative stability of biodiesel and is used biodiesel,” Bertram said. “If the processor
is utilizing a costly distilin conjunction with—or
lation step on the tail end
in place of—the water- What is perhaps most
to remove metals or
wash treatment in the
attractive about
other contaminants, they
biodiesel
production
Magnesol, is that it
could forgo that step
process.
also.
In
addition,
After the glycerin works simply and
separation
process, relatively inexpensively. Magnesol has a high
affinity for methanol and
methyl esters contain
water, so it will remove
contaminant materials
that are detrimental to the quality of the the last bits from methl esters..”
Purification with Magnesol also
fuel and must be eliminated from the
product. Reduction of the water-soluble increases the oxidative stability of
contaminants, traditionally, is accom- biodiesel, Bertram said, which is becoming
plished by water-washing the biodiesel. increasingly important, due to the
However, according to Bertram, the era of demands being placed on fuel producers
the biodiesel water-wash may be gradually by the auto manufacturing industry and
ending. “The water-wash method does government.
Magnesol, which can be used in either
nothing to remove the water-insoluble
March 2005 z BIODIESEL MAGAZINE
40
PROCESS
Drying
Methyl
Esters
Catalyst
(NaOH)
+ Methanol
Transesterification
Contaminated
Methyl
Esters
Vegetable
Oils, used
cooking oil,
animal fats
Water
Washing
Methyl
Esters &
Residual
Water
Dirty
Effluent
Glycerin
Biodiesel Production with
Adsorbent Purification
Methanol
Removal
Catalyst
(NaOH)
+ Methanol
Transesterification
Vegetable
Oils, used
cooking oil,
animal fats
Contaminated
Methyl
Esters
Adsorbent
Purification
Methyl
Esters
BIODIESEL MAGAZINE z March 2005
Methanol
Removal
41
Biodiesel Production with a
Water-wash Treatment
batch or continuous processes, removes
residual methanol, providing a cost savings in the stripping step. Magnesol is
able to remove sulfur, which is especially important in light of impending U.S.
EPA regulations that will limit sulfur in
diesel fuel to 15 parts per million.
Furthermore, the product significantly
reduces a plant’s need for heated and
conditioned water. The traditionally
employed water-wash method necessitates either the purchase of centrifuges
or the gravity-separation of the water
from biodiesel.
“After transesterification, you have
methyl esters that need purification,”
Bertram said, explaining how water
washing is typically used to remove contaminants from methyl esters.
Abrams said The Dallas Group
believes the water-wash method has several limitations, including decreased
yields due to methyl ester loss in effluent; high soap levels that cause emulsification; high effluent treatment and disposal costs; and the time and cost of
drying methyl esters. High soap levels in
particular may lead to poor separation,
contribute to yield losses and require
multiple washes to achieve specification,
Abrams said. In some cases, 24 hours are
required to effect a single separation.
Additionally, it is not uncommon
for producers to end up with a methyl
ester/water emulsion. “Without a waterwash, there are no such emulsions
formed,” Abrams said. “The disposal,
and even permitting of, wastewater is
difficult to impossible, depending on
plant location. Magnesol greatly reduces
dependency on water and resultant
wastewater disposal issues.”
What is perhaps most attractive
about Magnesol, is that it works simply
and relatively inexpensively.
Cooke shared information about
Magnesol at the 2005 National Biodiesel
Conference & Expo in Ft. Lauderdale,
Fla., in early February. His presentation—essentially a detailed explanation
of how biodiesel can be purified by
using the company’s trademarked adsorbent—covered the basic biodiesel
process, the technology of filtration
(passive and active), the results of a pilot
Glycerin
Filter
Cake
Animal Feed
Fuel Value (Biomass)
Compost
PROCESS
Biodiesel Purification Process
Magnesol ®
Unwashed biodiesel
(after separation and after methanol removal)
Finished
Product
Tank
Mix
Tank
Benefits of
treatment with
MAGNESOL ®
✔No water-effluent stream
✔No emulsification
✔Improved oxidative stability (OSI)
✔Minimal yield loss
✔Minimal capital expenditure
✔Allows for continuous operation
✔Expedites the purification process
✔Adsorbs residual water
Filter
plant trial that involved the product, and a
brief look at replacing the water-wash step
with the company’s magnesium silicate
treatment.
Cooke explained that Magnesol could
be used by biodiesel producers as a “total
replacement” of the water wash step, or a
“polishing step” used to round out the
water wash treatment.
In a standard biodiesel production
process, Magnesol—a fine white powder—is mixed with unwashed biodiesel in
a mixing tank (for five to 10 minutes) after
glycerin separation and after methanol
removal.
According to Cooke, magnesium silicate has a strong affinity for polar compounds, thereby actively filtering out
excess methanol, free glycerin, mono and
di-glycerides and metal contaminants, in
addition to free fatty acids and soap.
These materials are then removed from
the process through filtration. Note:
Glycerin is a polar molecule, and thereby
susceptible to the adsorptive abilities of
magnesium silicate. That’s why Magnesol
is added to the process after the glycerin
separation step.
Explaining the difference between
“passive filtration” and “active filtration,”
Cooke said Magnesol has “charged sites”
on its surface (areas that attract the afore
mentioned unwanted polar compounds).
“Adsorptive sites may have either
acidic or basic characteristics,” he said,
before explaining the testing methods
used to measure the number—and
strength—of adsorptive sites on a given
amount of adsorbent matter such as
Magnesol.
Cooke said testing has shown that
synthetic magnesium silicate has high
numbers of acidic and basic adsorptive
sites, as opposed to passive filter-aid-type
materials like diatomaceous earth, which
“did not have any active filtration sites.”
With the use of Magnesol, Cooke
said, the producer is left with a potentially
valuable “filter cake” rather than dirty
effluent. Clients of The Dallas Group are
currently exploring a variety of markets
for this filter cake, and the company
believes the byproduct has potential value
as an animal feed supplement, a form of
biomass fuel, fertilizer or compost.
The BECON study
The Dallas Group has over 30 years
experience in the purification of various
chemicals, including esters and the resulting byproducts of those processes. In
addition to its own in-house work on
biodiesel (with outside lab confirmation),
the Biomass Energy Conversion Facility
(BECON) at Iowa State University performed trials comparing the traditional
water-wash method to biodiesel purification with Magnesol. Results from this
study were discussed by Cooke in his
presentation and also by Dr. Jon Van
Gerpen during a special technology session at the National Biodiesel Conference.
Van Gerpen, a respected authority on the
subject of biodiesel, directed the pilot
study at the BECON facility. He has since
taken a position at the University of Idaho
as department head of Biological and
Agricultural Engineering.
In that study, methyl esters were produced in 40-gallon batches from both
degummed soybean oil and yellow grease
March 2005 z BIODIESEL MAGAZINE
42
PROCESS
feedstocks in BECON’s pilot plant reactor. In both cases, the methanol was
removed from the methyl esters, but not
initially water-washed.
First, 20 gallons of the soybean
methyl esters were water-washed and
dried, while another 20 gallons were treated at 77 degrees Celsius with 1-percent-byweight Magnesol. After 20 minutes of mixing (longer than is probably required in a
commercial plant setting, Cooke said), the
purified methyl ester was filtered. The
resulting biodiesel from both methods
passed all specifications of ASTM D6751. According to the study’s authors,
Van Gerpen and Kirk Menges, the
Magnesol-treated biodiesel contained a
lower soap and sodium content than the
water-washed
and
dried
sample.
Furthermore, the Magnesol-treated
biodiesel showed a significant improvement in oxidative stability when compared
to both the original methyl esters and the
water-washed and dried sample.
In a second trial, 20 gallons of the
yellow grease methyl esters were waterwashed and dried and 20 gallons were
treated with at 77 degrees Celsius with 2percent-by-weight Magnesol. After 20
minutes of mixing, the purified methyl
ester was filtered. Like the first test with
soy methyl esters, the Magnesol-treated
sample of yellow grease-derived methyl
esters passed all ASTM specifications
while the waterwashed and dried sample
did not. The Magnesol-treated biodiesel
contained a lower soap and sodium content than the water-washed and dried sample. Again, the Magnesol-treated biodiesel
showed a significant improvement in
oxidative stability when compared to both
the original methyl esters and the waterwashed and dried sample.
During his presentation, Cooke concluded that the benefits of treating methyl
esters with Magensol are multi-fold. He
reiterated Bertram’s claims about the
product: With Magnesol, there is no water
effluent, no emulsification, improved
oxidative stability, minimal yield loss and
minimal capital expenditure, all through
an application that “expedites the purification process and allows for continuous
operation.”
Fielding questions from attendees,
Cooke said the cost of using Magnesol is
in the range of 1 cent to 10 cents per gallon of finished biodiesel, depending on
the starting contaminant level. However,
he reminded attendees that the filter cake
could potentially be used as an animal
feed. “It has a certain nutritional value,” he
said.
According to Bertram, the capital
costs of transitioning a biodiesel facility to
Magnesol are relatively low. That’s because
only a low-tech filtering system is required.
In addition to potentially eliminating the
drying step and the requirement for a
wastewater treatment system, the use of
Magnesol could replace a centrifuge, yielding additional savings of capital, time and
maintenance costs.
There are less obvious savings, too,
MAGNESOL
®
Bertram said. “Magnesol actually offers
the biodiesel producer a lot of latitude in
running their process,” he said. “It adsorbs
glycerin, free glycerin, metals, soaps,
chlorophyll, residual free fatty acids, odors,
color, methanol and water. Since Magnesol
adsorbs such a wide range of impurities, it
compensates for upstream upsets in the
process, offering clean and more stable
biodiesel.” „
For more information about Magnesol visit
www.dallasgrp.com.
Tom Bryan is editorial director of Biodiesel
Magazine. Reach him by e-mail at
[email protected] or by phone at (701)
746-8385.
This article was printed in the 2005 March issue of
Biodiesel Magazine.
PURIFICATION
OF BIODIESEL
AND OTHER HIGH-PURITY ESTERS
• Guarantee biodiesel quality
(ASTM D6751)
• Reduce or eliminate water wash
• Eliminate emulsions
• Expedite purification process
• Reduce energy requirements
• Increase process yield
• Improve storage stability (OSI)
PHONE 812-283-6675 Ext. 5
EMAIL [email protected]
WEB www.dallasgrp.com
0605I203
43
BIODIESEL MAGAZINE z March 2005
J a n u a r y
2 0 0 8
w w w . B i o d i e s e l M a g a z i n e . c o m
TECHNOLOGY
Cleaner
and
Clearer
In a challenging economic environment, producing a top
quality product is one way to maintain a competitive
edge. For biodiesel producers, that means finding the
most economical way to wash and polish their crude
biodiesel to the highest possible standard. Schroeder
Industries says its system can produce clean biodiesel
quickly and inexpensively.
By Jerry W. Kram
Pictured are before and after samples of fuel washed using
Schroeder Industries Magnesol-based dry-wash system.
PHOTO: SCHROEDER INDUSTRIES
© Biodiesel Magazine, 2008
ARTICLE WAS PRINTED IN JANUARY 2008 ISSUE OF BIODIESEL MAGAZINE
Reprinted with permission from Biodiesel Magazine. Call (701) 738-4999 for reprints, republications or other uses and permissions. January 2008.
J a n u a r y
2 0 0 8
w w w . B i o d i e s e l M a g a z i n e . c o m
TECHNOLOGY
Q
uality is the name of the
game in biodiesel these days.
Filter-clogging impurities
made headlines in 2006 and
biodiesel producers don’t need adverse
press in an economically demanding era.
With any business, entrepreneurs rise to
the challenge and create innovative and
economical solutions to industry problems. “Purification is only one part of
the production process and is one, in
our opinion, that is too frequently overlooked,” says Michael Benzies of
Filtertechnik. “Industry standards are
becoming increasingly stringent and
upstream procedures need to be
adhered to in order to be in a position to
even start purifying.”
A key step in producing quality
biodiesel is washing to remove impurities such as excess caustic catalyst,
methanol, soaps and free glycerin.
Along with filter clogging, unwashed
biodiesel can cause seal failures, clogged
fuel injectors, damaged fuel pumps and
other problems in diesel engines. In the
United States, the most common
method of removing these impurities is
wet washing. Wet washing uses water as
a solvent to carry away the impurities,
leaving the pure biodiesel behind. But
wet washing has disadvantages. It’s a
time-consuming step requiring many
hours for the biodiesel and water to
completely separate. Wet washing can
also leave residual traces of water in the
fuel. “In drier areas you may have water
restrictions,” Benzies says. “You may
need some treatment if you have really
hard water. But the real problem comes
with the high levels of soaps and emulsions that form if the wet wash isn’t performed properly. You then have a risk of
having a very poor separation of the
fuel and the water and an extended separation time. The final problem is the
disposal of the hazardous effluent waste
which is the byproduct of the wet wash.
It may be that you have to wash seven or
eight times in order to achieve clarity.”
Dry washing is an alternative. In dry
washing, an adsorbent is added that
attracts and combines with impurities,
separating them from the biodiesel.
Some systems use ion exchange resins as
the adsorbent (see “Waterless Washing
Machine” in the May 2007 issue), while
others use a mineral called magnesium
silicate, one type of which is marketed
under the name Magnesol by the Dallas
Group of America Inc. Recently, lubricant purification specialist Schroeder
Industries became the exclusive distributor for a Magnesol-based dry-wash system created by Filtertechnik. “Having
looked at various dry-wash systems
including competitive silicates and resin
systems, we decided to run with the
Magnesol product based on several factors: first and foremost, it’s one of the
few products that had independent verification put on it,” Benzies says. “It’s
one of the few products that published
performance data, which is absolutely
vital.”
Keeping Watch
Schroeder’s system works in a similar fashion to other dry-wash systems
(see “Adsorbing It All” in the March
2005 issue). After crude glycerine is separated and removed, and excess
methanol is vented, Magnesol powder is
added to a tank of biodiesel and agitated with a mixer for about 25 minutes.
The process uses 0.5 percent to 1 percent Magnesol by weight, depending on
the level of contaminants in the batch
of biodiesel. So, 2,000 pounds of
biodiesel, which is about 265 gallons,
would require 20 pounds of Magnesol.
The powder attracts polar molecules
and separates them from the nonpolar
biodiesel. Methanol, water, glycerin and
catalysts are all polar molecules. “That’s
effectively what happens when the
Magnesol comes in contact with the
crude methyl ester,” Benzies says. “It
adsorbs all the impurities.”
After agitation, the biodiesel is circulated through Schroeder’s wash
columns to filter out the Magnesol and
its cargo of contaminants. “Moving
across to the wash stage, it is at this time
when we start to see things improving in
terms of visual clarity,” Benzies says.
“The advantage of using our systems in
conjunction with Magnesol is that the
towers enhance the clean-up process. At
this point we see a rise in clarity for the
first time. The milkiness and cloudiness
that you see in your crude methyl ester
is now replaced by a bright, golden crisp
color.”
After the biodiesel reaches the
desired level of clarity, it is transferred
to a final polish tank. Schoeder recommends that all biodiesel go through a
polishing step to maintain stringent
quality standards, irrespective of the
washing method. They also encourage
biodiesel producers to be rigorous with
their own quality testing. “We are the
only producer of filter and purification
systems that actually encourage producers to do these tests simply because they
don’t lie to you, and will tell you exactly
how good your purification method is,”
Benzies says.
Schroeder’s polishing filter units
can handle from 500 liters per hour (132
gallons per hour) to 2,500 liters per hour
© Biodiesel Magazine, 2008
ARTICLE WAS PRINTED IN JANUARY 2008 ISSUE OF BIODIESEL MAGAZINE
Reprinted with permission from Biodiesel Magazine. Call (701) 738-4999 for reprints, republications or other uses and permissions. January 2008.
J a n u a r y
2 0 0 8
w w w . B i o d i e s e l M a g a z i n e . c o m
(661 gallons per hour) and remove
residual particulates and water. An innovative part of the units is the built-in
monitoring systems that include particulate counters and water monitors. The
monitors display the level of contamination on liquid crystal display screens and
can be downloaded to a computer for
real-time monitoring and batch tracking.
The system can also send e-mail alerts
and even download alerts to cell phones.
“Archiving traceability, building up
records, having control of your production process is absolutely important,”
Benzies says. “If someone has problems
with their vehicle they instinctively
blame the fuel. That’s one of the things
producers have to keep in mind, they
need to have some sort of in-house
traceability that says that that particular
batch was a good batch.”
Performance
Magnesol was compared with wet
washing by researchers at Iowa State
University, Benzies says. The results
showed significant results after just 20
minutes of processing. “The performance data showed a massive decrease in
glycerin and the moisture removal capability and methanol reduction,” he says.
“More importantly, if you look at the
soap reduction capability, it’s just staggering in a short space of time to get
from a high level to an acceptable level.
That is one of reasons we have
embraced this dry-wash medium.”
The dry-wash systems have other
benefits. The cost of operating a drywash system is lower than a wet-wash
system. Disposal and water treatment
costs are also lower with a dry-wash system. Lower cost is not the biggest sell-
PHOTO: SCHROEDER INDUSTRIES
TECHNOLOGY
The BD-6000 Final Polishing Unit can be outfitted
with Schroeder Particle and Moisture monitoring
technology.
ing point, according to Benzies. “In our
opinion, producers change from wet to
dry for two reasons, speed and fuel quality” he says.
Filtertecknik compared biodiesel
produced by its system with other commercially available fuels, with surprising
results, Benzies says. “When we did particle counts on standard petrodiesel, it
was shocking how dirty it turned out to
be,” he says. “Now we are under no illusions that it didn’t leave the refinery at
this cleanliness level, but with so many
underground storage facilities and dirty
nozzles, this is the cleanliness level that
is being used in a lot of the motor vehicles today.” Wet-washed biodiesel was
cleaner than the petrodiesel. The drywashed biodiesel was cleaner still, with a
lower moisture level than the wetwashed biodiesel.
Trends
Since 2004, biodiesel producers in
the United Kingdom have adopted drywash systems. That year, 70 percent of
producers used wet washing and 20 percent didn’t wash their biodiesel at all. By
2006, 43 percent of producers surveyed
were dry washing their biodiesel and 47
percent were still using wet-washing systems. “It wouldn’t surprise me if the dry
systems were to surpass the wet systems
[in 2007],” Benzies says. The reasons for
this shift were because wet-wash producers were experiencing problems, drywash systems have now come into their
own and are available on the market,
and industry standards have become
more stringent, he says.
U.S. biodiesel producers are also
interested in this new technology, says
Jonathan Dugan, a product specialist
with Schroeder Industries. However,
with the current financial challenges facing the industry, producers are being
cautious with capital investments. He
says they talked to a couple of producers about developing the technology.
“There has been some frustration with
folks on the capital equipment side asking ‘Why isn’t anybody buying anything?’” Dugan says. “Until the government puts on a tax credit or we figure
out a cheaper feedstock, it’s a little bit of
a waiting game. But if crude goes up
another $20 or $30 we could see a swing
where biodiesel is profitable again. At
this time, people aren’t interested in
retrofits. They are more interested in
paying for the technology they’ve
already purchased.”
In addition, many producers are
hesitant to change from a well-established process. “Some of it has been
slow going,” Dugan says. “The acceptance has been good. But it has been
confusing for some about how they
would apply it. Water washing has been
the de facto standard for quite some
time. Adsorbent technology is new to
© Biodiesel Magazine, 2008
ARTICLE WAS PRINTED IN JANUARY 2008 ISSUE OF BIODIESEL MAGAZINE
Reprinted with permission from Biodiesel Magazine. Call (701) 738-4999 for reprints, republications or other uses and permissions. January 2008.
J a n u a r y
2 0 0 8
w w w . B i o d i e s e l M a g a z i n e . c o m
TECHNOLOGY
Take water out of the equation…
Dry Wash your biodiesel!
™
MAGNESOL® D-SOL
eliminates the need
for water wash and...
• SAVES TIME…
Purify biodiesel in minutes,
not hours and with no messy
emulsions.
• SAVES CAPITAL…
No need for expensive
centrifuges, dryers, or
settling tanks.
• SAVES ENERGY…
No drying required.
• ELIMINATES WATER…
No water permitting. No
expensive water pre-treatment
or post-treatment systems.
folks so we are trying to explain to them
how it works and why it works and how
it can save them money. But it’s coming
along.”
Tightening water supplies, plus the
cost of treating effluent in many areas
of the United States will be a factor in
biodiesel production, Dugan says. He
described a visit to a biodiesel producer
who used wet washing largely because
he had a favorable agreement with the
municipal water and sewer service
providers. “They said if the local
municipality hadn’t been so gracious in
helping to get the business started, they
would have had to go to Magnesol and
a dry-wash process,” he says. “When
they build their next plant, it may be a
different story. It has everything to do
with the local rules and government.”
Despite the current challenges in
the biodiesel industry, there are still a
lot people interested in building new
plants. These companies are taking a
good hard look at using dry washing,
Dugan says. “We have spoken to a lot of
folks,” he says. “We have our systems
specified into a lot of medium-sized
plants and we’re talking to some of the
larger plants. I think that as soon as it
makes sense to build up the industry
capacity, we will see an influx of business that we can’t even imagine. That’s
really exciting for us.” Jerry W. Kram is a Biodiesel Magazine
staff writer. Reach him at jkram
@bbibiofuels.com or (701) 738-4962.
PHONE [1] 812-283-6675 Ext. 5
EMAIL [email protected]
WEB www.dallasgrp.com
© Biodiesel Magazine, 2008
ARTICLE WAS PRINTED IN JANUARY 2008 ISSUE OF BIODIESEL MAGAZINE
Reprinted with permission from Biodiesel Magazine. Call (701) 738-4999 for reprints, republications or other uses and permissions. January 2008.
ANNEX VI: CENTRIFUGE AND AC DRIVE
1.Centrifuge
The centrifuge used in the different trials is a Basic Raw Power Centrifuge, which is
manufactured by WVO Designs. Its main characteristics, which can be found in http://
wvodesigns.com/ are the following:
- The Basic Raw Power Centrifuge runs at 3450rpm and produces over 1200Gs.
- This entry level centrifuge is the lowest cost way to get out of filtering waste oil.
Consider the optional bolt-on heater to increase flow rates to 15gph.
- Single Pass: Adjust flow rate to suit your feedstock and cleaning requirements
- Quiet: Custom US Made Motor operates smooth and quiet(it will be quieter than an A/
C Unit)
- No Pressure: High pressure pumps and fittings are expensive and leaks costly
- Direct Drive: Rotor speed is unquestionable and you can't get a simpler design
- High Capacity: Rotor holds over half a litre so you can remove pounds of GUNK and
clean hundreds of gallons between cleanings
- Modular Design: Start with the basic unit and upgrade as your needs require
Different videos about how is it assembled and how does it work can be found in the next
links:
http://vimeo.com/8238179
http://www.youtube.com/watch?v=cUhgKFV5Ri4
http://www.youtube.com/watch?v=5cvQazPlzKU
http://www.youtube.com/watch?v=pagHQKvaC9k
2.AC Drive
A GS1 AC Drive was used as a motor drive for the centrifuge. In this way, the rpm of the
centrifuge could be maximised up to 6000 rpm and the spinning speed could also be
controlled with it. In the next pages the complete overview of the drive is attached.
GS1 Series Introduction
GS1 Series Drives
Hp
kW
115 Volt Single-Phase Input/230 Volt Three-Phase Output
230 Volt Single-Phase Input/230 Volt Three-Phase Output
230 Volt Three-Phase Input/Output
Motor Rating
Overview
The GS1 series of AC drives is our most
affordable and compact inverter, offering
V/Hz control with general purpose application features. These drives can be
configured using the built-in digital keypad
(which also allows you to set the drive
speed, start and stop, and monitor specific
parameters) or with the standard RS-485
serial communications port. Standard
GS1 features include one analog input,
four programmable digital inputs and one
programmable normally open relay
output.
Features
.25
0.2
.5
0.4
1
0.75
✔
✔
✔
✔
✔
2
1.5
✔
Accessories
• Simple Volts/Hertz control
• Pulse Width Modulation (PWM)
• 3 – 10 kHz carrier frequency
• IGBT technology
• 130% starting torque at 5Hz
• 150% rated current for one minute
• Electronic overload protection
• Stall prevention
• Adjustable accel and decel ramps
• S-curve settings for acceleration and
deceleration
• Manual torque boost
• Automatic slip compensation
• DC braking
• Built-in EMI filter
• Three skip frequencies
• Trip history
• Integral keypad and speed potentiometer
• Programmable jog speed
• Three programmable preset speeds
• Four programmable digital inputs
• One programmable analog input
• One programmable relay output
• RS-485 Modbus communications up to
19.2K
• Optional Ethernet communications
• UL/cUL/CE listed
• AC line reactors
• RF filter
• Ethernet interface
• Four and eight port RS-485 multi-drop
termination board
• KEPDirect I/O Server
• GSoft drive configuration software
• GS-485HD15-CBL - ZIPLink RS485
Communication cable for connection
to the DL06 and D2-260 15-pin ports.
Detailed descriptions and specifications for the
accessories are available in the “GS/DURAPULSE
Accessories” section.
Typical Applications
• Conveyors
• Fans
• Pumps
• Shop tools
GS1 series part numbering system
GS1 - 2 0P5
Applicable Motor Capacity
0P2: 1/4hp
1P0: 1hp
0P5: 1/2hp
2P0: 2hp
Input Voltage
1: 100-120VAC
2: 200-240VAC
Series Name
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GS1 Series Specifications
Company
Information
Systems
Overview
115V/230V CLASS GS1 Series
Model
GS1-10P2
Price
Motor Rating
HP
kW
Rated Output Capacity (200V) kVA
Rated Input Voltage
Rated Output Voltage
Rated Input Current (A)
Rated Output Current (A)
Watt Loss @ 100% I (W)
Weight: kg (lb)
Dimensions (HxWxD) (mm [in])
GS1-10P5
GS1-20P2
GS1-20P5
GS1-21P0
GS1-22P0
<--->
<--->
<--->
<--->
<--->
<--->
1/4 hp
1/2 hp
1/4 hp
1/2 hp
1hp
2hp
0.2 kW
0.4 kW
0.2 kW
0.4 kW
0.7 kW
1.5 kW
0.6
1.0
0.6
1.0
1.6
2.7
Single-phase 100-120 VAC 앧10%,
50/60 Hz 앧5%
Single/three-phase: 200-240 VAC±10%, 50/60 Hz ±5%
Three-phase: 200240 VAC±10%,
50/60 Hz ±5%
Programmable
Controllers
Field I/O
Software
C-more &
other HMI
Drives
Three-phase corresponds to double the
input voltage
Three-phase corresponds to the input voltage
6
9
4.9/1.9
6.5/2.7
9.7/5.1
9
1.6
2.5
1.6
2.5
4.2
7.0
19.2
19.2
18.4
26.8
44.6
73
2.10
2.20
2.20
2.20
2.20
2.20
Soft
Starters
Motors &
Gearbox
Steppers/
Servos
132.0 x 68.0 x128.1 [5.20 x 2.68 x 5.04]
Motor
Controls
Accessories
Ethernet Communications module for GS Series
Drives (DIN rail mounted)
Four port RS-485 multi-drop termination board
Eight port RS-485 multi-drop termination board
Software
OPC Server
Proximity
Sensors
GS-EDRV
GS-RS485-4
Photo
Sensors
GS-RS485-8
GSoft / KEPDirect
Limit
Switches
KEPDirect
Encoders
Current
Sensors
Pressure
Sensors
Temperature
Sensors
Pushbuttons/
Lights
Process
Relays/
Timers
Comm.
Terminal
Blocks &
Wiring
Power
Circuit
Protection
Enclosures
Tools
Pneumatics
Appendix
Product
Index
Part #
Index
Volume 13
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Drives/Motors/Motion
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GS1 General Specifications
General Specifications
Control Characteristics
Control System
Rated Output Frequency
Output Frequency Resolution
Overload Capacity
Torque Characteristics
DC Braking
Acceleration/Deceleration Time
Sinusoidal Pulse Width Modulation, carrier frequency 3kHz - 10kHz
Voltage/Frequency Pattern
V/F pattern adjustable. Settings available for Constant Torque - low and high starting torque, Variable Torque low and high starting torque, and user configured
Stall Prevention Level
20 to 200% or rated current
1.0 to 400.0 Hz limited to 9999 motor rpm
0.1 Hz
150% of rated current for 1 minute
Includes manual torque boost, auto-slip compensation, starting torque 130% @ 5.0Hz
Operation frequency 60-0Hz, 0-30% rated voltage. Start time 0.0-5.0 seconds. Stop time 0.0-25.0 seconds
0.1 to 600 seconds (can be set individually)
Operation Specification
Frequency
Setting
Inputs
Operation
Setting
Outputs
Keypad
Setting by <UP> or <DOWN> buttons or potentiometer
External Signal
Potentiometer - 5k액 0.5W, 0 to 10 VDC (input impedance 47k액), 0 to 20 mA / 4 to 20 mA (input impedance
250액), Multi-function inputs 1 to 3 (3 steps, JOG, UP/DOWN command), RS485 communication setting
Keypad
External Signal
Setting by <RUN>, <STOP> buttons
Multi-Function Input Signal
Multi-step selection 0 to 3, Jog, Accel/decel inhibit, First/second accel/decel switch, Counter, PLC operation,
External base block (N.C., N.O.) selection
Multi-Function Output Signal
AC drive operating, Frequency attained, Non zero speed, Base Block, Fault indication, Local/remote indication,
PLC operation indication
Operating Functions
Automatic voltage regulation, S-curve, Over-voltage stall prevention, DC braking, Fault records, Adjustable carried frequency, Starting frequency setting of DC braking, Over-current stall prevention, Momentary power loss
restart, Reverse inhibition, Frequency limits, Parameter lock/reset
Protective Functions
Operator Devices
Programming
Operator
Interface
Parameter Monitor
Environment
DI1, DI2, DI3, DI4 can be combined to offer various modes of operation, RS485 communication port
Key Functions
Enclosure Rating
Ambient Operating Temperature
Storage Temperature
Ambient Humidity
Vibration
Installation Location
Options
Overcurrent, overvoltage, undervoltage, electronic thermal motor overload, Overheating, Overload, Self testing
5-key, 4-digit, 7-segment LED, 3 status LEDs, potentiometer
Parameter values for setup and review, fault codes
Master Frequency, Output Frequency, Scaled Output Frequency, Output Voltage, DC Bus Voltage, Output
Direction, Trip Event Monitor, Trip History Monitor
RUN/STOP, DISPLAY/RESET, PROGRAM/ENTER, <UP>, <DOWN>
Protected chassis, IP20
-10° to 40°C (14°F to 104°F) w/o derating
-20° to 60 °C (-4°F to 140°F) during short-term transportation period)
0 to 90% RH (non-condensing)
9.8 m/s2(1G), less than 10Hz. 5.88 m/s2 (0.6G) 20 to 50 Hz
Altitude 1000m or lower above sea level, keep from corrosive gas, liquid and dust
Programming Software (GSOFT)
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GS1 Specifications - Installation
Company
Information
Systems
Overview
Understanding the installation requirements
for your GS1 drive will help to ensure that it
will operate within its environmental and electrical limits.
Programmable
Controllers
NOTE:
Never use only this catalog for installation instructions or
operation of equipment; refer to the user manual, GS1-M.
Field I/O
Software
Environmental Specifications
Protective Structure
Ambient Operating
Temperature 2
Storage
Temperature 3
IP20
Humidity
to 90%
(no condensation)
Vibration 4
5.9 m/s2 (0.6g),
10 to 55 Hz
Location
Altitude 1,000 m or less,
indoors (no corrosive
gases or dust)
C-more &
other HMI
Fan
Drives
6"
150mm
min
-10 to 40°C
-20 to 60°C
Soft
Starters
Motors &
Gearbox
2"
50mm
min
Steppers/
Servos
2"
50mm
min
2: The ambient temperature must be in the range of
-10° to 40° C. If the range will be up to 50° C, you
will need to set the carrier frequency to 2.1 kHz or
less and derate the output current to 80% or less.
See our Web site for derating curves.
Limit
Switches
6"
150mm
min
Encoders
3: The storage temperature refers to the short-term
temperature during transport.
Current
Sensors
4: Conforms to the test method specified in JIS CO911
(1984)
Pressure
Sensors
Panel
GS1 Drive Model
At full load
GS1-10P2
GS1-10P5
GS1-20P2
GS1-20P5
GS1-21P0
GS1-22P0
19.2
Ground braid
copper lugs
Input
Power
Temperature
Sensors
To
Motor
Pushbuttons/
Lights
* FOR PAINTED SUB-PANELS,
19.2
SCRAPE THE PAINT FROM UNDER-
18.4
NEATH THE STAR WASHERS
26.8
Proximity
Sensors
Photo
Sensors
1: Protective structure is based upon EN60529
Watt-loss Chart
Motor
Controls
Star washers*
Panel or single
point ground*
BEFORE TIGHTENING THEM.
Process
Relays/
Timers
Comm.
44.6
73
Air Flow
Warning: AC drives generate a large
amount of heat, which may damage the
AC drive. Auxiliary cooling methods
are typically required in order to not
exceed maximum ambient
temperatures.
Terminal
Blocks &
Wiring
Power
Circuit
Protection
Enclosures
Tools
Pneumatics
Appendix
Product
Index
Part #
Index
Volume 13
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GS1 Specifications - Terminals
Main Circuit Wiring
Terminal
Description
L1, L2, L3
T1, T2, T3
Input power
AC drive output
Ground
Control Circuit Terminals
1
Terminal Symbol
Description
R1O
R1
DI1
DI2
DI3
DI4
AI 1
+10V
CM
Relay output 1 normally open
Relay output 1 common
Digital input 1
Digital input 2
Digital input 3
Digital input 4
Analog input
Internal power supply (10 mA @ 10 VDC)
Common
0 to +10 VDC, 0 to 20 mA, or 4 to 20 mA input represents zero to maximum output frequency.
Note: Use twisted-shielded, twisted-pair or shielded-lead wires for the control signal wiring. It is recommended
all signal wiring be run in a separate steel conduit. The shield wire should only be connected at the drive.
Do not connect shield wire on both ends.
Volume 13
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GS1 Specifications - Basic Wiring Diagram
Company
Information
Systems
Overview
Note: Users MUST connect wiring according to the circuit diagram shown below. (Refer to user manual GS1-M for additional specific wiring information.)
Programmable
Controllers
Note: Refer to the following pages for explanations and information regarding line reactors and RF filters: 13-50, 13-67.
Field I/O
Power Source 3-phase*
100-120V±10%
(50/60Hz ±5%)
200-240V±10%
(50/60Hz±5%)
AC Motor
L1
L2
GS1-xxxx
T1
IM
T2
T3
Steppers/
Servos
Motor
Controls
Grounding resistance
less than 0.1⏲
Multi-function output contacts
120VAC/24VDC @5A
230VAC @2.5A
R1O
External Fault (N.0)
DI1
R1
Fault Indication
RJ-12 Serial Comm Port*
Interface (See Warning)
DI3
6
1
RS-485
2: GND
3: SG4: SG+
5: +5V
Jog
Analog voltage
0-10VDC
Potentiometer
3~5k⏲
Analog current
0-20mA; 4-20mA
Communication Port
Current
Sensors
Pressure
Sensors
Temperature
Sensors
Pushbuttons/
Lights
*Optional ZIPLink RS485
Communication cable GS-485HD15CBL available for connection to the
DL06 and D2-260 15-pin
ports. See page 12-75.
+10V 10mA
(max)
AI
Photo
Sensors
Encoders
RJ-12 (6P4C)
CM
Proximity
Sensors
Limit
Switches
DI2
DI4
Common Signal
Drives
Motors &
Gearbox
* Use terminals L1 and L2 for 120V, or
select any two of the power terminals
for 240V single-phase models
Reverse/Stop
C-more &
other HMI
Soft
Starters
L3
Forward/Stop
Software
Process
Relays/
Timers
Comm.
Terminal
Blocks &
Wiring
Power
CM
Circuit
Protection
Enclosures
Tools
Factory default setting
Pneumatics
Factory default source of frequency command is via the keypad potentiometer
Main circuit (power) terminals
Control circuit terminal
Appendix
Shielded leads
Product
Index
Part #
Index
WARNING: Do not plug a modem or telephone into the GS1 RJ-12 Serial Comm Port, or permanent damage may result.
Terminals 2 and 5 should not be used as a power source for your communication connection.
Volume 13
w w w. a u to m at i o n d i re c t . c o m / d r i ves
Drives/Motors/Motion
e13-19
GS1 Specifications - Dimensions
68.0 (2.68)
)
20
56.0 (2.20)
.
.5
dia
0.
0(
STOP
RUN
FWD
REV
0
PROG
ENTER
100
132.0 (5.20)
RUN
STOP
120.0 (4.72)
DISPL
RESET
V
I
R1 R1O+ 10V AI DI1 DI2 DI3 DI4 CM
128.1 (5.04)
123.4 (4.86)
128.1 (5.04)
Unit: mm (in)
Volume 13
e13-20
Drives/Motors/Motion
1 - 80 0 - 633 - 0405
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