Method for producing synthetic natural gas by utilizing impermeable gas after hydrogen recovery

Abstract

The invention discloses a method for producing synthetic natural gas by utilizing impermeable gas after hydrogen recovery. Methyl alcohol purge gas and impermeable gas after hydrogen recovery and hydrogen enrichment enter a high-pressure primary isothermal methanation reactor through a gas-gas heat exchanger without pressure reduction, H2 and CO2 in the impermeable gas react to generate methane atthe temperature of 250-380 DEG C, under the pressure of 1.0-7.0 MPa and under the effect of a nickel catalyst, CO methanation reaction heat is recovered in the isothermal methanation reactor throughmedium-pressure boiler water in the form of a biproduct medium-pressure steam of 4.0-4.5 MPa, heat transfer and temperature control are achieved through water during methanation reaction, the temperature is easy to control without setting of a circular compressor for temperature control, the high pressure and low temperature are both conductive to balanced conversion of the methanation reaction, the requirement of feeding into a natural gas pipeline can be met only through primary isothermal methanation reaction, and liquidated cryogenic separation and other treatment are not needed. The impermeable gas after hydrogen recovery is used as raw gas for high-pressure primary isothermal methanation, and the prepared gas can be directly fed into the natural gas delivery pipeline without liquidated cryogenic 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