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Method and system for recovering helium from helium-containing tail gas

A tail gas and helium technology, applied in chemical instruments and methods, inert gas compounds, inorganic chemistry, etc., can solve the problems of high cost, high energy consumption of helium recovery, large operating flexibility, etc., and achieve the effect of low cost

Pending Publication Date: 2022-02-18
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The present invention aims at the problem of high energy consumption and high cost of recovering helium from BOG tail gas of liquefied natural gas (LNG) plants in the prior art, and provides a new method for recovering helium from BOG tail gas of LNG plants. According to the helium-rich characteristics of the LNG plant, a high-performance helium separation membrane is used creatively to remove CH in BOG gas 4 , N 2 etc., and then use catalytic degassing method to remove H 2 (to avoid explosion caused by dehydrogenation and heating in the presence of methane), and finally use the adsorption method to enrich the helium to more than 99.99%. This method has the technical advantages of low energy consumption and large operating flexibility

Method used

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  • Method and system for recovering helium from helium-containing tail gas
  • Method and system for recovering helium from helium-containing tail gas
  • Method and system for recovering helium from helium-containing tail gas

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Experimental program
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Effect test

Embodiment 1

[0069] BOG gas in an LNG plant consists of He, N 2 、CH 4 、H 2 , O 2 Composition, its concentrations are 5.2312%, 1.5632%, 57.6317%, 35.5274%, 0.0465%. The following process is used to concentrate and recover helium, and Table 1 shows the composition of the gas obtained after being processed by each processing unit.

[0070] (1) Send the helium-rich BOG tail gas to the primary, secondary, and tertiary separation membrane units. The separation membrane adopts polyimide hollow fiber separation membrane, He / CH 4 The separation factor is 180, He / N 2 The separation factor is 160, and the He permeation rate is Most of the CH can be removed by the separation membrane 4 , N 2 , to obtain only He, H 2 and a small amount of CH 4 , N 2 permeate gas;

[0071] (2) Step (1) containing He, H 2 The permeate gas is sent to the catalytic dehydrogenation unit, and palladium is used to catalyze the removal of H 2 and CH 4 , to get He, H 2 O and a small amount of H 2 , CO 2 , N 2...

Embodiment 2

[0081] BOG gas in an LNG plant consists of He, N 2 、CH 4 、H 2 , O 2 Composition, its concentrations are 10.3578%, 2.6391%, 54.3247%, 32.6534%, 0.0250%, respectively. The following process is used to concentrate and recover helium, where Table 2 shows the composition of the gas obtained after being processed by each processing unit.

[0082] (1) Send the helium-rich BOG tail gas to the primary, secondary, and tertiary separation membrane units. The separation membrane adopts polyimide hollow fiber separation membrane, He / CH 4 The separation factor is 168, He / N 2 The separation coefficient is 152, and the He permeation rate is 95GPU. Most of the CH can be removed by the separation membrane 4 , N 2 , to obtain only He, H 2 and a small amount of CH 4 , N 2 permeate gas;

[0083] (2) Step (1) containing He, H 2 The permeate gas is sent to the catalytic dehydrogenation unit, and the Pt catalyst is used to catalyze the removal of H 2 and CH 4 , to get He, H 2 O and a s...

Embodiment 3

[0092] BOG gas in an LNG plant consists of He, N 2 、CH 4 、H 2 , O 2 Composition, its concentrations are 15.3869%, 5.3295%, 54.3247%, 32.6534%, 0.0250%, respectively. The following process is used to concentrate and recover helium, and Table 3 shows the composition of the gas obtained after being processed by each processing unit.

[0093] (1) Send the helium-rich BOG tail gas to the primary, secondary, and tertiary separation membrane units. The separation membrane adopts polyimide hollow fiber separation membrane, He / CH 4 The separation factor is 168, He / N 2 The separation coefficient is 152, and the He permeation rate is 95GPU. Most of the CH can be removed by the separation membrane 4 , N 2 , to obtain only He, H 2 and a small amount of CH 4 , N 2 permeate gas;

[0094] (2) Step (1) containing He, H 2 The permeate gas is sent to the catalytic dehydrogenation unit, and the ZnO catalyst is used to catalyze the removal of H 2 and CH 4 , to get He, H 2 O and a sm...

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Abstract

The invention provides a method and a system for recovering helium from helium-containing tail gas. The method provided by the invention comprises the following steps: s1, carrying out separation treatment on the helium-containing tail gas by a separation membrane to obtain permeated gas subjected to separation treatment by the separation membrane; s2, performing catalytic dehydrogenation treatment on the permeate gas obtained in the step S1 to obtain a mixed gas I after catalytic dehydrogenation; s3, carrying out decarburization treatment on the mixed gas I obtained in S2 to obtain mixed gas II subjected to decarburization treatment; s4, carrying out dehydration treatment on the mixed gas II obtained in S3 to obtain dehydrated mixed gas III; s5, carrying out adsorption treatment on the mixed gas III obtained in the S4 to obtain recovered helium. According to the method provided by the invention, high-purity helium can be efficiently recovered from the BOG tail gas, and the cost is low.

Description

technical field [0001] The invention relates to a method and system for recovering helium from tail gas containing helium. Background technique [0002] Helium is the known element with the lowest melting point and boiling point. It comes from the radioactive decay of elements such as uranium and thorium and the degassing of the mantle. Helium is widely used in aerospace industry, nuclear industry, scientific research, petrochemical, refrigeration, medical treatment, semiconductor, pipeline leak detection, superconducting experiment, metal manufacturing, deep-sea diving, high-precision welding, optoelectronic product production and other fields. It is a kind of national security shortage and strategic resources. [0003] The helium content of helium in the air is very small, with an average content of 5 / 1 million (volume fraction, the same below), which is difficult to achieve the purpose of economic development. In helium-rich natural gas, the content of helium can reach ...

Claims

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Application Information

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IPC IPC(8): C01B23/00
CPCC01B23/0094
Inventor 孟凡宁郦和生张新妙
Owner CHINA PETROLEUM & CHEM CORP