System and method for preparing high purity carbon monoxide and hydrogen-enriched co-production liquid methane

Abstract

The invention relates to the field of low-temperature gas separation, in particular to a system and method for preparing high purity carbon monoxide and hydrogen-enriched co-production liquid methane. The system mainly comprises a raw material gas purification unit, a low-temperature liquefying separation unit, a CO product compressor and a mixed refrigerant compressor. The low-temperature liquefying separation unit comprises a main heat exchanger, a methane washing tower, a dehydrogenation tower, a demethanization tower and a denitrification tower. A first evaporator is arranged at the bottom of the dehydrogenation tower; a second evaporator is arranged at the bottom of the demethanization tower; a first condenser is arranged on the top of the demethanization tower; a third evaporator is arranged at the bottom of the denitrification tower; and a second condenser is arranged on the top of the denitrification tower. According to the system and method, while high purity products rich in H2 and CO are obtained through four-tower process flow, high purity liquid methane can be obtained; the adaptability of a device to raw material gas is high; the requirement for raw material gas purities of the device is lowered; and part of CO is extracted from the tail stage or the middle stage of the CO product compressor to be used as a cold source and a heat source of a rectifying tower circularly according to the pressure of CO product gas, a nitrogen compressor and an expander are omitted, the number of devices is small, and the investment is small.

Description

technical field

[0001] The invention relates to the field of gas low-temperature separation, in particular to a system and method for producing high-purity carbon monoxide and hydrogen-rich gas to co-produce liquid methane. Background technique

[0002] CO and H 2 It is an important synthetic raw material in the chemical process, and is widely used in the synthesis of a series of organic chemical products and intermediates, while CO and H 2 The preparation of coal, natural gas or oil is generally used as raw materials, and it is obtained through a certain method transformation. In the preparation process, the effective components CO and H are removed. 2 In addition, a certain amount of CH 4 , N 2 , CO 2 Such impurities exist in the form of mixtures, and chemical synthesis processes usually require high-purity CO, which requires a suitable method to separate and purify the mixture.

[0003] CO and H 2 The separation methods mainly include pressure swing adsorption, mem...

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