A method and device for efficiently separating synthesis gas to produce hydrogen and carbon monoxide

Abstract

The invention relates to a method and device for efficiently separating synthesis gas to produce hydrogen and high-purity carbon monoxide. The invention adopts a methane washing tower (C1 tower) with an intermediate heat exchanger and a bottom reboiler, a tower top condenser and The deoxygenation-methane tower (C2 tower) with tower reboiler and the denitrification tower (C3 tower) with overhead condenser and tower reboiler are continuously rectified to produce hydrogen and high-purity carbon monoxide. The present invention adopts a methane washing tower with a reboiler and an intercooler, so that the synthesis gas with a hydrogen content of <0.5% can be obtained by using a single tower reactor. Because the hydrogen content of the tower reactor is relatively low, it is no longer necessary to install a steam generator. At the same time, it can realize the production of hydrogen and carbon monoxide with low energy consumption; it can produce 99.9% and more than 99.999% of carbon monoxide products; when the production pressure of carbon monoxide is higher than 0.2MPa, it is not necessary to set up a carbon monoxide compressor to achieve energy saving and saving The purpose of investing in and enhancing operational safety.

Description

Technical field [0001] The invention relates to a method for gas separation through cryogenic liquefaction, and in particular to a method for separating hydrogen, methane and carbon monoxide from synthesis gas. Background technique [0002] Carbon monoxide is usually obtained from synthesis gas produced by steam reforming catalytic conversion or partial oxidation from natural gas, coal and other hydrocarbons as raw materials. In addition to carbon monoxide, there are often hydrogen, nitrogen, methane, and oxygen in the gas. These impurity components often limit the use of carbon monoxide, so that many mixed gases containing a large amount of carbon monoxide can only be burned and vented, resulting in a waste of resources. [0003] Carbon monoxide and hydrogen are important basic chemical raw materials, widely used in chemical processes such as oxo synthesis, and have become important raw materials for a series of basic organic chemical products and intermediates. The source of ca...

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Problems solved by technology

The methane scrubber of this invention does not contain a reboiler, so it cannot be removed in one tower at a time. It is necessary to add a stripper to discharge hydrogen-rich gas at the top of the stripper. This gas cannot be used as a product gas, so the hydrogen extraction rate of the device lower

[0007] In the patent CN101568788B, the raw hydrogen gas enters the bottom of the C1 tower, and a C2 tower is required to remove the residual hydrogen. The raw materials with a hydrogen content > 1.5% in the C2 tower are removed at the top of the C2 tower. This part of the crude hydrogen cannot be used as a hydrogen product. Reduced hydrogen recovery

At the same time, in this patent, the decompressed carbon monoxide 29 enters the condensing evaporator of the C4 tower and evaporates into gas, then enters the main heat exchanger for reheating, enters the circulating compressor for boosting, and then outputs, and the carbon monoxide compressor has a safety function during operation risks of

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