The impact of ammonia on low-temperature methanol washing
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Could that expert tell me how ammonia specifically affects the operation of the low-temperature methanol washing system? (How should it mainly affect absorption?) ）
Ammonia provides the cooling capacity for cryogenic washing. Generally, there are 4 ammonia coolers. Since the amount of cooling provided varies, the temperature of the circulating methanol also changes, and as a result the absorption efficiency is definitely different.
Oh. I’m sorry, I was careless. What I meant to ask is: how exactly does the ammonia in the feed gas affect the operation of the low-temperature methanol washing system? (How should it mainly affect absorption?) ）
Ammonia has a higher solubility in methanol than hydrogen sulfide does. If the ammonia content is high, the absorption efficiency of hydrogen sulfide decreases. If the ammonia content in rich methanol is high, ammonium carbonate crystals are likely to form, blocking the pipes; therefore, an ammonia scrubbing tower is usually installed in such conversion processes.
Primarily, (NH4)2S is generated; upon entering the absorption tower with lean methanol, it decomposes, resulting in an excessive total sulfur content in the purified gas.
If the feed gas contains ammonia, then ammonia will react with hydrogen sulfide to form thiamine, leading to excessive levels of hydrogen sulfide; it will also react with carbon dioxide to form ammonium carbonate, which crystallizes at the top of the regeneration tower and blocks the hydrogen sulfide pipelines. I’m a beginner; that’s about all I know. I hope everyone can give me some guidance
There is a heat exchanger before the acid gas removal system; excess ammonia forms crystals, which block the heat exchange pipes and lead to an excess of ammonia. This, in turn, affects the acid gas in the absorption tower and the regeneration tower, resulting in a reduced absorption efficiency!
Ammonia in the feed gas reacts with carbon dioxide and hydrogen sulfide to form ammonium carbonate and thiamine, which clog the trays and result in reduced absorption efficiency as well as incomplete regeneration