Weekly Topic 3.21, Issue 19: Investigation into Methods for Removing Synthetic Inert Components
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This post was last edited by wawjia on 2011-3-21 08:12. As the title suggests, please share methods for removing the inert components (N2 and CO) in methanol synthesis! By the way, let me introduce the operation status
This post was last edited by wawjia on 2011-3-21 at 11:43. Method: Membrane separation. Volume of fresh gas synthesized: 200,000 m3/h. Volume of recycled gas: 600,000 m3/h. Maximum capacity designed for the membrane recovery unit: 30,000 m3/h. Operating condition: Good, with low pressure drop; the recovered hydrogen can be sent directly to the compressor inlet, and its purity exceeds 80%
In membrane separation, the recovered hydrogen is sent directly to the inlet of stage 3 of the compressor, with a purity of over 85%
The fresh gas flow rate is 100,000; previously, membrane separation was not used, and 3,000 cubic meters of gas were vented to the flare per hour. Recently, the exhaust gas volume has started to be a bit high at 4500. Membrane separation and hydrogen compressors. The hydrogen purity is greater than 93%, with a recovery rate of over 85%.
First, I would like to ask what process the original poster is using – why is CO considered an inert gas? Here, inert gases refer to gases such as N2, CH4, and Ar. The volume of fresh gas produced through membrane separation is over 200,000 m³/h, while the volume of recycled gas is over 500,000 m³/h. The maximum capacity designed for the membrane recovery unit is around 20,524 m³/h. The operation status is good, with low pressure drops; the recovered hydrogen can be directly fed into the inlet of the syngas compressor, and its purity exceeds 85%. In some ammonia production plants, this hydrogen is fed into the fourth stage inlet of the seven-stage compressor
The synthesized inert gas is sent in the form of vent gas to precise desulfurization and conversion for use as fuel gas.
Reply to 5# TH373637: For the synthesis of methanol from coal, when the components are quite heavy, CO acts as an inert component; it would be more accurate to say an excess component Although membrane separation removes N2, CO is also removed as well; my description wasn’t accurate
Oh, that’s how it should be understood. Thank you to the original poster
Pressure swing adsorption yields the best results for separating inert gas components; an 8-tower process is used, which is simple to operate and features a high degree of automation. The purity of hydrogen can reach over 99%. Inert gas is fed into the blowdown compressor, pressurized, and then sent to the boiler or waste heat boiler.
Our process involves the production of methanol from coke oven gas. Inert gases refer to N2, CH4, and Ar-based gases. The volume of fresh synthesis gas is around 34,000 m3/h, while the volume of recycled gas is around 370,000 m3/h. The maximum design capacity of the membrane recovery unit is around 20,000 m3/h. The operation status is good, with low pressure drops; the recovered off-gases can be directly fed into the inlet of the synthesis gas compressor or used as fuel in heaters and coke ovens. The purity of hydrogen reaches over 79.8%
Here, I use natural gas as the raw material; there is an excess of H2, but not enough CO! The original poster treats CO as an inert gas everywhere; it seems necessary to balance out methanol production from coal and that from natural gas~