Air separation system and method utilizing pressure energy of high-pressure natural gas pipeline network

Abstract

The invention discloses an air separation system and a method utilizing pressure energy of a high-pressure natural gas pipeline network. The air separation system comprises a natural gas pressure energy recovery system, an air separation system and a refrigerant circulation loop, wherein the natural gas pressure energy recovery system comprises a natural gas purification device, a high-pressure natural gas expansion machine, a high-pressure refrigerant compressor, a heat exchanger A, a refrigerant expansion machine, a medium-pressure refrigerant compressor, a medium-pressure natural gas expansion machine and a heat exchanger B, and the air separation system comprises a blower, an air filter, an air compressor, an air compressor aftercooler, an air precooler, a molecular sieve adsorption device, an electric heater, a main heat exchanger, an air expansion machine, a rectifying tower, an oxygen storage device and a nitrogen storage device. According to the air separation system, high pressure energy of high-pressure natural gas is converted into cold energy for air separation, the expansion machines and the heat exchangers are used as intermediate equipment for energy conversion, the pressure is reduced, and additionally, the pressure energy is fully refrigerated and used, so that the problems of high energy consumption and low pressure energy utilization of an air separation technique are solved.

Description

technical field [0001] The invention relates to the application technical field of high-pressure natural gas pressure difference refrigeration, in particular to a low-temperature air separation system and method for refrigeration by utilizing the pressure energy of a high-pressure natural gas pipeline network. Background technique [0002] Most of the natural gas pipeline network uses high pressure above 10MPa for long-distance transportation, while the design pressure of the urban gas pipeline network is 0.2-0.4MPa, which needs to be adjusted before being transported to the downstream pipeline network. There are two ways of secondary pressure regulation. The medium pressure standard of directly reducing the ultra-high pressure or high-pressure natural gas to 0.2MPa-0.4MPa (gauge pressure) is a first-level pressure regulation; first step down the ultra-high pressure or high-pressure natural gas to 1.6MPa-2.0MPa (gauge pressure), Then reduce the pressure again to 0.2MPa ~ 0....

AI Technical Summary

Problems solved by technology

The system combines two technologies of natural gas pressure energy recovery and air separation to convert the higher pressure energy of high-pressure natural gas into cold energy for air separation, and uses the expander and heat exchanger as intermediate equipment for energy conversion, which not only meets the pressure drop requirements, and can fully utilize the pressure energy of the natural gas pipeline network for refrigeration, and solve the problems of high energy consumption of the existing air separation technology and low energy utilization rate in the reuse of the pressure energy of the natural gas pipeline network

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