Recycling and helium-extracting co-production system and method for light hydrocarbons of helium-poor natural gas

Abstract

The invention discloses a recycling and helium-extracting co-production system and method for light hydrocarbons of helium-poor natural gas. The co-production system mainly comprises a heat exchanger,a low-temperature separator, a heavy contact tower, an ethane-removal device, a butane removal device, four flash tanks, three mixers, a plurality of compressors and a plurality of expanders. The co-production process utilizes an agent capable of automatically generating cold to refrigerate and expand a cold box to integrate heat exchange, and liquefied petroleum gas and stable light hydrocarbonsare obtained from raw material gas in the light hydrocarbon recycling device; dry gas of the light hydrocarbon recycling device enters a flash-evaporating helium-extracting device to gradually liquefy and separate to obtain LNG, externally conveyed gas and rough helium; and a low-temperature liquid-state natural gas product separated from the flash-evaporating helium-extracting device is taken asan agent capable of automatically generating cold through cascade cycle. Helium extracting and light hydrocarbon recycling are integrated, the heat exchanger is designed with high integrity, and theagent capable of automatically generating cold is adopted for cycle refrigeration; and compared with an existing process, the method overcomes the bottleneck of singe line production capacity, reducesliquefying cost and comprehensive energy consumption, improves performance, and has a practical application value.

Description

technical field [0001] The invention relates to the technical field of recovering helium from natural gas, in particular to a cogeneration system and method for recovering light hydrocarbons from helium-depleted natural gas and extracting helium. Background technique [0002] Helium is a very precious rare gas, especially in the application of national defense and cutting-edge scientific research, more and more people pay attention to helium. The main source of helium is helium-containing natural gas. The concentration of helium in natural gas is different in different regions. High-helium-containing natural gas is mainly concentrated in the United States and Russia. China is a helium-poor country. The reserves of helium resources are small and of poor quality. It is very difficult to develop and utilize them. my country's helium market with low helium production and high extraction costs. [0003] The cryogenic method is currently the most mature and widely used helium extr...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a helium-depleted natural gas for the problems of high energy consumption, insufficient process integration and low thermal design efficie

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