A natural gas precooling device and precooling control method

Abstract

The invention provides a natural gas precooling device and a precooling control method. The precooling device comprises a shield pump, a barrel pump, a heat exchanger and a cooling medium processing device. The precooling control method comprises the steps that pressure in the barrel pump is controlled to stay within a preset pressure range; the shield pump is controlled to transport a low-temperature liquid cooling medium in the barrel pump to the front end of a cold box system; the heat exchanger is controlled to utilize the low-temperature liquid cooling medium to conduct precooling treatment on natural gas at the front end of the cold box system, so that the natural gas of a preset temperature and a gaseous cooling medium of the preset temperature are output; and the cooling medium processing device is controlled to convert the gaseous cooling medium in the barrel pump into the low-temperature liquid cooling medium in order to facilitate reclamation. According to the natural gas precooling device and the precooling method, the natural gas can be precooled, the liquefaction ratio of the natural gas can be improved when precooled natural gas is subjected to liquefaction, recycling gas is reduced, and liquefaction cost of the natural gas is lowered.

Description

technical field [0001] The invention relates to the technical field of energy and chemical industry, in particular to a natural gas precooling device and a precooling control method. Background technique [0002] In the existing technology, natural gas at 40°C and 20Mpa directly enters the cold box for high-pressure jet flow, 1 / 4 of the natural gas is liquefied, and 3 / 4 of the circulating gas returns to the compressor for repressurization cycle, that is, the liquefaction rate of natural gas is relatively low , the amount of recycle gas is large, and the amount of re-pressurization of recycle gas is too much, resulting in high liquefaction cost of natural gas. Contents of the invention [0003] In view of this, the present invention provides a natural gas precooling device and a precooling control method, which are used to solve the problem of low liquefaction rate of natural gas, large recycle gas volume, and too much repressurization of recycle gas in the prior art. , le...

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Problems solved by technology

[0003] In view of this, the present invention provides a natural gas precooling device and a precooling control method, which are used to solve the problem of low liquefaction rate of natural gas, large recycle gas volume, and too much repressurization of recycle gas in the prior art. , leading to the problem of high liquefaction cost of natural gas, the technical solution is as follows:

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