Methanol synthesis
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Colleagues, may I ask what is meant by off-gas in the methanol synthesis process? If you know, please tell me your valuable answer
I hadn’t thought about it. Okay~! But its composition is similar to that of the recirculated air.
1. Flare gas generally refers to the components such as H2, N2, and CO that are dissolved in the methanol discharged from the separator. After the methanol is sent to an intermediate tank, depressurization occurs, causing the dissolved gases to come out; the gas that is discharged under reduced pressure from the storage tank is known as flare gas. 2. In some cases, after the methanol outlet stream is washed, part of the gas that can be discharged and recovered is vented to maintain an inert gas balance; this gas is referred to as purge gas.
In the methanol synthesis process, vent gas refers to the gases dissolved in the methanol that are released from the crude methanol intermediate tank or storage vessel (which is under pressure); such gases are known as vent gas； If part of the recycle gas is vented to ensure that the level of inert gases in the recycle gas used in the methanol synthesis process does not exceed the specified limits, this portion is referred to as vent gas; some plants also call it purge gas.
Blowdown gas is the gas that is blown out behind the methanol separator, with the purpose of removing the inert gases from the loop.
The methanol discharged from the separator contains dissolved components such as H2, N2, and CO; after being sent to an intermediate tank, it is depressurized, causing the dissolved gases to come out. The gas released under reduced pressure from the storage tank is known as flash vapor. After separating methanol, the gas that can be released and recovered is vented to maintain an inert gas balance; this gas is known as purge gas.
The so-called vent gas refers to the gas that is released after the alcohol separation; it can be used for hydrogen extraction and then the resulting waste gas can be burned. From a design perspective, since this is the area with the highest concentration of inert gases in the entire system, emissions are carried out from here.
The vent gas is arranged after water separation and washing, mainly for use as fuel.!
The off-gas from our plant is a gas containing components such as H2, N2, CO, and CH4, which results from cooling the gas released from the synthesis tower and then subjecting it to separation and washing.
The purge gas, also known as the blowing gas, is primarily composed of inert gases (N2), with small amounts of active gases as well (CO, CO2, H2). In our facility, it is installed after the separator, as this is when the concentration of inert gases is highest; therefore, it makes sense to place the purge system here. All our purge gases are recovered and used for ammonia synthesis purification. Because the active gas for ammonia synthesis is N2. Additionally, our bleed air can also control the system pressure.
In the methanol synthesis process, vent gas refers to the gases dissolved in the methanol that are released from the crude methanol intermediate tank or storage vessel (which is under pressure); such gases are known as vent gas； If part of the recycle gas is vented to ensure that the level of inert gases in the recycle gas used in the methanol synthesis process does not exceed the specified limits, this portion is referred to as vent gas; some plants also call it purge gas.