Method and equipment for co-production of high-purity helium through natural gas liquefaction

Abstract

The invention relates to a method and equipment for co-production of high-purity helium through natural gas liquefaction. The method comprises the following steps: taking non-condensable tail gas or BOG as raw material gas, and firstly introducing the raw material gas into a gas inlet buffer tank for flow stabilization treatment; then entering a first-stage membrane separator assembly for membrane separation and then sequentially passing through a gas buffer tank A and a compressor; then entering a second-stage membrane separator assembly; extracting and separating high-purity hydrogen and crude helium from the gas through a hydrogen recovery tower, and enabling the tail gas to enter a PSA denitrification device; purifying the crude helium again through a PSA drying and purifying device; and then treating the helium by a helium compressor and a low-temperature purifier to obtain high-purity helium. The equipment comprises the gas inlet buffer tank, the first-stage membrane separator assembly, the gas buffer tank A, the compressor, the second-stage membrane separator assembly, the hydrogen recovery tower, the PSA drying and purifying device, the helium compressor and the low-temperature purifier which are connected in sequence. The method and the equipment are used for recovering, separating and purifying helium-containing components of the non-condensable tail gas or the BOG in a cold box of a natural gas liquefaction factory, the high-purity hydrogen and helium can be obtained at the same time, and meanwhile the LNG yield is increased.

Description

technical field [0001] The invention relates to a helium production method and equipment, in particular to a natural gas liquefaction co-production method and equipment for high-purity helium, belonging to the technical field of helium recovery. Background technique [0002] Helium is a colorless and odorless inert gas, widely used in optical fiber, semiconductor, medical, national defense and many other fields, and is a non-renewable scarce strategic resource. Helium is widely used and used in a large amount, but its sources are limited. The helium content in the air is about 5ppm, which has no extraction value. At present, it mainly comes from the recovery of associated helium in natural gas exploitation. [0003] my country is a typical helium-poor country, and the content of helium associated with natural gas is generally 0.02-0.05%. The direct recovery and extraction of helium from natural gas faces problems such as complex technology, high cost, and low economic effici...

AI Technical Summary

Problems solved by technology

However, it still has the following disadvantages: 1) Because the membrane separation is driven by medium and high pressure, the feed gas needs to be pressurized, which increases the power consumption; 2) Due to the large amount of flash gas, the power consumption required for gas compression is also large , so it needs to consume a lot of electric energy; 3) Helium and hydrogen cannot be obtained at the same time, resulting in a waste of hydrogen resources

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