AppliedAnalytics TLG 837 Tail Gas bro

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

220

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

220 230

Off-Ratio Performance

Under various upset conditions, the H

2

S / SO

2

ratio may deviate widely from 2:1 in either direction. Some modified Claus process designs, including Superclaus™, operate with a controlled ratio much higher than 2:1. A high-performing tail gas analyzer must therefore be able to remain accurate even when this ratio is well outside the expected range.

Some photometers claim good response to off-ratio conditions, but in practice are limited by the single-wavelength measurement. No single photodiode can be reliable for both high level H

2

S and low level H

2

S due of the unavoidable limits of light saturation (at too-low concentration) and over-absorbance (at too-high concentration). Additionally, the lack of confirmation wavelengths permits a noise level which cripples accuracy in certain off-ratio scenarios.

By virtue of full spectrum acquisition, the TLG-837 sustains the specified accuracy when H

2

S / SO

2

ratio reaches as high as 100:1, or as low as 1:20 . This huge range makes the system robust enough for virtually any process scenario.

lighted 210-240 nm region where the cross-absorbance occurs — for accuracy in off-ratio conditions. The TLG-837 measurement is not impacted by light saturation or over-absorbance at a single photodiode because confirmation wavelengths negate this error.

230

8

8

6

6

240

4

4

2

Wavelength (nm)

0

250

220

260 270

240

10:1 H

2

S / SO

280 290

Wavelength (nm)

300

280

1.8

1:10 H

2

S / SO

2

Ratio Condition

1.4

TTL2

1

0.6

0.2

0

220

Wavelength (nm)

240

[12]

Wavelength (nm)

280

H S (10%)

SO (1%)

300

H S (0.2%)

SO (2.0%)

300