COS levels are above the limit, and hexa elements in the exhaust gases are also above the limit
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Ladies and gentlemen, our plant uses LUCCHI low-temperature methanol washing units, which were just put into operation recently. The level of COS in the syngas is consistently above the acceptable limit, while the H2S level in the syngas is practically zero. We have adjusted the circulation rate as well as the thermal regeneration system, but with little effect. Also, the H2S level in the exhaust gases is always above the limit; please help me
An excessive amount of nitrogen used for gas stripping can easily lead to excessive H2S levels in the exhaust gases
The amount of carefully purified methanol needs to be increased! COS belongs to organic sulfur; if a low amount was specified during the initial design, this problem may arise now due to a significant increase in COS levels.
Reasons for the excessive COS level in syngas: First, as you mentioned, it is due to adjustments in circulation volume, temperature, and thermal regeneration. Second, check whether the content of methanol in water is too high, and improve the operation of the methanol-water separation tower. The excessive total sulfur content in the exhaust gas of the exhaust gas scrubber needs to be considered from two aspects: one is the CO2 gas, and the other is the gas-lifted exhaust gas; it is necessary to determine which one has a higher total sulfur content, so as to ensure a proper distribution of sulfur-free methanol.