A method of using hydrogen to recover non-permeate gas to produce synthetic natural gas

Abstract

The method of using hydrogen to recycle non-permeable gas to produce synthetic natural gas. The non-permeable gas after methanol purge gas is reclaimed by hydrogen and rich in hydrogen does not need to be decompressed and enters a high-pressure first-stage isothermal methanation reactor through a gas-gas heat exchanger. The temperature is 250-380 ℃, pressure 1.0-7.0MPa and nickel catalyst, the H in the non-permeate gas 2 , CO and CO 2 The reaction produces methane, and the CO methanation reaction heat is recovered in the isothermal methanation reactor through medium-pressure boiler water in the form of by-product medium-pressure steam of 4.0-4.5Mpa. The temperature of the methanation reaction is controlled by water transfer heat, and the temperature is easy to control. There is no need to set up a circulating compressor for temperature control. Both high pressure and low temperature are conducive to the balanced conversion of methanation reaction. Only one-stage methanation reaction is required to meet the requirements of sending natural gas pipelines, and no liquefaction cryogenic separation and other treatments are required. In the present invention, the non-permeable gas after hydrogen recovery is used as raw material gas for high-pressure isothermal methanation, and the obtained gas can be directly sent into a natural gas pipeline without cryogenic liquefaction and separation.

Description

technical field [0001] The invention relates to a method for producing synthetic natural gas by using hydrogen to recover non-permeable gas, in particular to a method for producing synthetic natural gas by using non-permeable gas recovered from hydrogen-rich non-permeable gas from methanol purge gas. Background technique [0002] Methanol is an important chemical raw material, which is widely used in coal chemical, petrochemical, transportation and other industries. At present, methanol mainly reacts with carbon monoxide, carbon dioxide, and hydrogen as raw materials under the action of a certain temperature, pressure, and Cu-based methanol catalyst to form methanol. However, since the reaction of carbon monoxide, carbon dioxide, and hydrogen to generate methanol is a reversible reaction, the single-pass conversion rate of synthetic methanol is low. Therefore, the current common practice is to condense and separate the liquid phase products, leaving most of the unreacted gas...

AI Technical Summary

Problems solved by technology

Methanol and methane are both chemical products. It is absolutely unnecessary to synthesize synthesis gas into methanol first, then crack it into synthesis gas and then synthesize methane, which is economically unreasonable

[0009] CN104557390 A proposes a method of utilizing methanol purge gas to co-produce liquid methane. The method uses methanol purge gas as a raw material without hydrogen recovery, and the raw material gas is relatively rich in hydrogen; at a temperature of 430-480°C, methane is synthesized. The reaction temperature is high, which is not conducive to the equilibrium conversion of methane

Images