High sulfur dioxide concentration in exhaust gases?
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Acid is produced from 100,000 tons of lead flue gas using a \"3+2\" two-conversion two-absorption process with pre-conversion and pre-absorption; the heat exchanger sequence is 3.1-5.4.2. The conversion temperature and the concentration of acid after dry absorption are within the normal control ranges, and the inlet concentration of sulfur dioxide is 12% – so why is the sulfur dioxide concentration in the exhaust gases as high as 900 mg/m3? Suspecting a perforation in the heat exchange tubes of Heat Exchanger No. 3 – how can this be determined during production?
Basically normal; a desulfurization device must be installed after this process
Just the previous month, the concentration of sulfur dioxide in exhaust gases remained between 400-500 mg/m3, with all parameters remaining unchanged; yet recently it has risen to 900 mg/m3
With all parameters unchanged, the only possibility is a leak in stage 5, which causes direct leakage into the second absorption tower; a leak in stage 3 will result in an increase in the gas concentration in stage 4, as well as an increase in temperature
What is considered a normal temperature difference across the four sections?
There are two possibilities: One is that there is an internal leak in the heat exchanger between sections 4 and 5； Secondly: there is a possibility of weld cracks in the partition plate between sections 4 and 5 of the converter itself; we have encountered this issue, where the conversion efficiency in section 5 is low and the SO2 emission concentration in the exhaust gases is high.
Just calculate the sulfur dioxide concentration at the inlet and outlet of each layer as well as the stage-wise conversion rate
The analysis and testing personnel in the plant do not carry out sampling and analysis of gas samples; the quality of the conversion is generally determined based on experience by observing the temperature differences across various sections, and no significant abnormalities in these temperature differences have been detected so far
A change of four units generally has little impact on the conversion temperature; drain the condensate acid from each heat exchanger
Which high-concentration conversion process are you using? Is it three transformations and three absorptions?
Laboratory analysis data are the operator’s eyes; without analysis, it’s like trying to understand an elephant by feeling it. Segment conversion rate is easy to measure; a missing value represents a significant error.