In the Lurgi low-temperature methanol wash process, what is the role of gases and steam entering the tail gas scrubber tower?
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In the LUCI low-temperature methanol washing process, how many gas streams are there in the off-gas washing tower? Which route has the largest gas capacity? Also, what is the purpose of the steam injection line before the gas enters the tower? Furthermore, if this steam is used to regulate the temperature of the gas entering the tower, what is the typical temperature at which the gas enters the tower, and why is it necessary to control this temperature? Thank you.
In the low-temperature methanol washing process used for methanol production, there are two streams of gas that enter the exhaust gas washing tower: one is the CO2 gas coming from the carbon dioxide desorption tower, and the other is the exhaust gas from the hydrogen sulfide concentration tower. These two streams combine before entering the exhaust gas washing tower; typically, the temperature of these combined gases is maintained between 25 and 30 degrees Celsius. The steam pipeline is used to control the temperature of the gas entering the tower, preventing low-temperature gas from freezing upon entering the exhaust gas scrubber.
We use a 10-tower process; there are two streams that go to the exhaust gas treatment system. Steam is added to prevent freezing of the condensate water due to low temperatures. Those two streams come from stage 3 of the CO2 flash tower and stage 2 of the hydrogen sulfide concentration tower – they are mostly composed of CO2, with the latter stream having a larger volume. The inlet temperature for these streams is generally around 10°. The first stream is divided into three smaller streams for heat exchange, and ultimately all of them end up in the exhaust gas scrubber, though their temperatures have increased by then. The three streams have temperatures of 0°, 30°, and 20° respectively, and they all enter the exhaust gas scrubber together