High-nitrogen-content and high-helium-content natural gas liquefaction and crude helium and nitrogen extraction system

Abstract

The invention discloses a high-nitrogen-content and high-helium-content natural gas liquefaction and crude helium and nitrogen extraction system and belongs to the technical field of extraction systems. The high-nitrogen-content and high-helium-content natural gas liquefaction and crude helium and nitrogen extraction system comprises a crude helium condenser. The crude helium condenser respectively communicates with a second liquid nitrogen throttle valve, a liquid nitrogen subcooler, a crude helium separator and a demethanizer condensation separator. The crude helium separator respectively communicates with a liquid nitrogen subcooler and a first liquid nitrogen throttle valve, the other end of the first liquid nitrogen throttle valve communicates with a flash steam separator, the flash steam separator communicates with the liquid nitrogen subcooler, and the liquid nitrogen subcooler communicates with a liquid nitrogen evaporation pressure control valve. The other end of the liquid nitrogen evaporation pressure control valve communicates with a demethanizer condenser. Natural gas is little diffused, the helium extraction efficiency is high, meanwhile, nitrogen in the natural gas is extracted to produce liquid nitrogen and nitrogen products, and the economic benefits are good.

Description

technical field [0001] The invention relates to an extraction system, in particular to a system for liquefying high-nitrogen and helium-containing natural gas and extracting crude helium and nitrogen, and belongs to the technical field of extraction systems. Background technique [0002] Helium is a kind of inert gas and an important strategic material. As a protective gas and ultra-low temperature refrigerant, it has very important uses in aerospace, national defense, semiconductor production, nuclear magnetic resonance and gas leak detection. Helium mainly exists in In natural gas, the extraction of helium from natural gas is the main industrial source of helium. The content of helium in natural gas in my country is small, and the cost of extracting helium from natural gas alone is high. Liquefied natural gas is a kind of clean energy. With the rise of domestic natural gas liquefaction devices , the implementation of LNG and crude helium extraction co-production makes helium...

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Problems solved by technology

[0002] Helium is a kind of inert gas and an important strategic material. As a protective gas and ultra-low temperature refrigerant, it has very important uses in aerospace, national defense, semiconductor production, nuclear magnetic resonance and gas leak detection. Helium mainly exists in In natural gas, the extraction of helium from natural gas is the main industrial source of helium. The content of helium in natural gas in my country is small, and the cost of extracting helium from natural gas alone is high. Liquefied natural gas is a kind of clean energy. With the rise of domestic natural gas liquefaction devices , the implementation of LNG and crude helium extraction co-production makes helium extraction economically feasible; for natural gas with low nitrogen content, crude helium can be extracted in LNG flash gas after natural gas liquefaction, while in the prior art there is Natural gas releases a lot, the efficiency of extracting helium is low, and it is impossible to extract nitrogen from natural gas to produce liquid nitrogen and nitrogen products, resulting in energy waste and recycling, so a liquefaction and liquefaction of natural gas with high nitrogen and helium content is designed for this purpose. Crude helium and nitrogen extraction systems to optimize the above issues

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