Why must the hot regeneration reflux stream from low-temperature methanol washing, which contains H2S, be passed through an enriched gas cryocooler to reach -34°C?
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The temperature of the H2S-containing gas in the heat regeneration reflux tank of the low-temperature methanol wash is 34°C; it is reduced to 25°C after passing through the rich gas heater, then to -34°C after going through the rich gas cryocooler. Why is deep cooling to -34°C necessary?
Since the gas is saturated with methanol, cooling and separation can minimize the amount of methanol carried in the gas.
1. By reducing the temperature of the acidic gas, its saturated vapor pressure of methanol decreases; as a result, most of the methanol vapor in the acidic gas is condensed, so less methanol is carried away by the acidic gas, leading to reduced methanol losses. If the temperature of the acidic gas returning to the hydrogen sulfide concentration tower is too high, it will inevitably cause the temperatures of the methanol streams in that tower to rise, which in turn will affect the temperature of the lean methanol and thus its ability to absorb CO2 and H2S.
Reduce the methanol content in the acidic gas transmission clause, while simultaneously decreasing methanol consumption
Lowering the temperature is primarily aimed at reducing the large amount of methanol contained in the acidic gases, thereby decreasing methanol consumption.
To further recover methanol and reduce its loss, the liquid level in the separator is generally kept at around 10%.
Actually, there’s no need to lower the temperature that much; we only reduced it to around -20 degrees! And our design value is only -28 degrees!
It is mainly to recover methanol and reduce methanol losses
The main purpose is to recover methanol, prevent it from entering the sulfur recovery process, and reduce methanol consumption.
What was said on the fourth floor is absolutely correct. The most important thing is to recover methanol, and as for the destination of the recovered methanol, it goes to the CO2 concentration tower; therefore, the temperature there cannot be too high. For 300,000 tons of methanol, we need to replenish about 20 tons of methanol per month.
Reply to 11# Shouhou: Lower temperatures are conducive to condensation. The purpose of 1 is to reduce methanol losses by recovering it. 2 To ensure that the acid gas in the out-of-bound area meets the specifications