Production system for extracting crude helium from natural gas and co-producing liquefied natural gas

Abstract

The invention discloses a production system for extracting crude helium from natural gas and co-producing liquefied natural gas. The production system comprises a first-stage helium extraction unit, a second-stage helium extraction unit, a third-stage helium extraction unit, a mixed refrigeration system and a nitrogen refrigeration system, wherein the first-stage helium extraction unit, the second-stage helium extraction unit and the third-stage helium extraction unit are connected through pipelines. The first-stage helium extraction unit comprises a heat exchanger I, an LNG storage tank, a rectifying tower I, and a condenser I and a reboiler I which are arranged at the tower top and the tower bottom of the rectifying tower I correspondingly. The second-stage helium extraction unit comprises a heat exchanger II, a rectifying tower II, and a condenser II and a reboiler II which are arranged at the tower top and the tower bottom of the rectifying tower II correspondingly. The third-stage helium extraction unit comprises a heat exchanger III, a rectifying tower III, and a condenser III and a reboiler III which are arranged at the tower top and the tower bottom of the rectifying tower III correspondingly. According to the production system, the technical scheme of mixed refrigerant circulating refrigeration and three-stage rectification helium extraction is adopted, helium is produced as a main product, a small part of liquefied natural gas and liquid nitrogen products are produced as byproducts, and the problems of high investment, high operation cost and the like in an existing helium extraction and liquefied natural gas co-production process can be effectively solved.

Description

technical field [0001] The invention belongs to the technical field of chemical separation, relates to extracting helium from natural gas, in particular to a production system for extracting crude helium from natural gas and co-producing liquefied natural gas. Background technique [0002] Helium is mainly used in low temperature, aerospace, electronics industry, biomedicine, nuclear facilities and other fields, and is one of the basic materials for national security and high-tech industry development. With the development of my country's national economy, the demand for helium is on the rise. However, the total amount of natural gas resources in my country is poor, and the helium content is relatively low. The production level of helium is far from meeting the requirements of science and technology, economic construction, and national defense and military industry development. [0003] The preparation methods of helium mainly include the following four methods: (1) natural...

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Problems solved by technology

[0007] Aiming at the problems of large investment, high operating cost and high energy consumption in the existing natural gas helium extraction technology, the purpose of the present invention is to provide a production system for extracting crude helium from natural gas and co-producing liquefied natural gas. The system uses mixed refrigerant The technical scheme of circulating refrigeration + three-stage rectification to extract helium produces helium as the main product, with a small amount of liquefied natural gas and liquid nitrogen as by-products. This system can effectively solve the problems existing in the existing helium extraction and co-production of liquefied natural gas. The problem of high investment and energy consumption not only retains most of the advantages of natural gas liquefaction to produce helium to reduce the investment cost of helium, but also realizes the flexibility of production of helium and LNG products, and realizes the adjustment of LNG production according to market demand

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