Film method for recycling CO in high-pressure exhaust from production of acetic acid by carbonylation

Abstract

The invention discloses a method for recovering CO from a high-pressure acetic acid tail gas produced by carbonylation through a membrane process and a device thereof. The tail gas is treated by three steps, that is, pretreatment, membrane separation and gas compression: the tail gas that passes a gas washing tower, a demister and a combined filter enters a Prisen membrane separator through a heater, the tail gas after the membrane separation enters a compressor, a product gas is recovered and reused, and hydrogen rich gas flows to a torch for burning. In the method, two Prisen membrane systems help control the amount of the feed gas entering a membrane, the product gas and the hydrogen rich gas to reach N2 material balance, ensure the CO recovery rate and achieve the purpose of the long and stable operation of a membrane separation device; and the content of the CO in the final product gas is not less than 91%.

Description

technical field [0001] The invention relates to a technology for purifying CO from mixed tail gas discharged from acetic acid production, in particular to a recovery method for CO in high-pressure tail gas produced by carbonylation of acetic acid. Background technique [0002] Since the early 1970s, Prick proposed carbonylation with carbon monoxide and methanol in U.S. Patent No. 3,769,329, and adopted rhodium, methyl iodide, methyl acetate, water, etc. as catalysts to produce acetic acid. This technology has been fully industrialized by the world. More than 75% of the total amount of acetic acid is produced by this method, which has the advantages of high methanol selectivity, simple purification, compact process flow, and low production cost. Although this method has contributed to the optimization of the acetic acid production process in the carbonylation production of acetic acid reaction solution and catalyst research in recent decades by large-scale acetic acid product...

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Problems solved by technology

[0006] However, the membrane separation technology has high requirements on the gas entering the membrane. At present, in the high-pressure tail gas recovery of acetic acid produced by carbonylation, due to the presence of acetic acid, moisture and other components that are easy to damage the membrane in the tail gas, the membrane separation technology cannot be directly used.

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