Separation and recovery device and method for argon and methane in synthetic ammonia relief gas

Abstract

The invention relates to a separation and recovery device and a method for argon and methane in synthetic ammonia relief gas, the separation and recovery device comprises a cold box, a raw material relief gas pipeline, a purification system which is communicated with the raw material relief gas pipeline and provided with a first molecular sieve adsorber MS1 and a second molecular sieve adsorber MS2, a refrigeration system for providing cold energy required for separating and liquefying, and a distillation system for separating raw material relief gas stage by stage, wherein the refrigeration system comprises a low-pressure circulation nitrogen compressor TC1, a medium-pressure circulation nitrogen compressor TC2, a low-temperature pressurized turbo-expander ET2, a high-temperature pressurized turbo-expander ET1, a main heat exchanger E1 and a liquefier E2, the distillation system comprises a flash evaporation tank S2, a dehydrogenation tower C1 equipped with a first condenser K4 and afirst evaporator K1, a dehydrogenation tower C2 equipped with a second condenser K5 and a second evaporator K2 and a product tower 3 equipped with a third condenser K6 and a third evaporator K3. The invention can obtain high product purify and high recovery rate.

Description

technical field [0001] The invention relates to the field of gas separation, in particular to a device and method for separating and recovering argon and methane in the purge gas of synthetic ammonia. Background technique [0002] The nitrogen required in the ammonia production process comes from air, so the argon will be carried along with the air. Moreover, because the methane in the raw material cannot be completely converted, or the methanation process is adopted in the gas-making process, some methane is added to the synthetic raw material gas. Since argon and methane are non-reactive in the synthesis system, they will inevitably accumulate in the system, so the synthesis system must often draw a part of the purge gas. The purge gas will naturally contain certain amounts of hydrogen and nitrogen in addition to argon and methane. Usually, most of the hydrogen and nitrogen with higher content are recycled, and the remaining purge gas containing hydrogen, nitrogen, argon...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the deficiency that only hydrogen and nitrogen can be recovered in the purge gas of synthetic ammonia at present, and argon and methane cannot be separated and purified, the present invention prov

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