Mixed refrigerant re-circulated liquefaction process for precooling coalbed methane (CBM) by residual pressure of pressure swing adsorption (PSA)

A technology of mixed refrigerants and pressure swing adsorption, which is applied in refrigeration and liquefaction, liquefaction, chemical industry, etc., can solve the problems of reduction and insignificant energy saving effect of coalbed methane, and achieve the effect of reducing the power consumption of liquefaction

Inactive Publication Date: 2010-01-13
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Zhu Jiaxin, who majored in refrigeration and low temperature at Shanghai Jiaotong University, used the adsorption-liquefaction method to realize the liquefaction of coalbed methane in his master's thesis. In the refrigerant cycle li

Method used

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  • Mixed refrigerant re-circulated liquefaction process for precooling coalbed methane (CBM) by residual pressure of pressure swing adsorption (PSA)
  • Mixed refrigerant re-circulated liquefaction process for precooling coalbed methane (CBM) by residual pressure of pressure swing adsorption (PSA)
  • Mixed refrigerant re-circulated liquefaction process for precooling coalbed methane (CBM) by residual pressure of pressure swing adsorption (PSA)

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Experimental program
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Effect test

Embodiment approach 1

[0020] Implementation Option 1: If figure 1 As shown, the coalbed methane mixed refrigerant circulation liquefaction process using pressure swing adsorption residual pressure precooling in the four-stage cooling process when the temperature after precooling of coalbed methane is greater than 0 ° C includes the following steps:

[0021] 1. Water, acid gas and heavy hydrocarbon impurities are removed in the pre-purification system 1 of the pressurized normal-temperature coalbed methane raw material gas;

[0022] 2. The pre-purified coalbed methane is concentrated in the adsorber 2 through the pressure swing adsorption process, and the concentrated coalbed methane with residual pressure nitrogen and normal pressure is separated;

[0023] 3. The concentrated coalbed methane is compressed to a medium pressure of 0.6-0.8 MPa by the primary methane compressor 4 and compressed by the secondary methane compressor 6 to be greater than or equal to 4.5 MPa, and is respectively cooled in t...

Embodiment approach 2

[0027] Implementation Option 2: If figure 2 As shown, the coalbed methane mixed refrigerant circulation liquefaction process using pressure swing adsorption residual pressure precooling in the three-stage cooling process when the temperature after precooling of coalbed methane is -60 ~ 0 ° C includes the following steps:

[0028] Step 1, step 2, step 3 and step 4 are respectively the same as step 1, step 2, step 3 and step 4 in embodiment 1;

[0029]5. The pre-cooled concentrated coalbed methane is cooled to -60°C by the second heat exchanger 14, cooled to -130°C by the fourth heat exchanger 20 and cooled to -155°C by the fifth heat exchanger 22 to become a low-temperature coal seam The cooling capacity in these three heat exchangers is provided by the mixed refrigerant cycle. The above-mentioned mixed refrigerant cycle is as follows: a certain amount of mixed refrigerant at normal temperature and pressure is compressed to a medium pressure of 0.8-1.0 MPa by the primary refr...

Embodiment approach 3

[0031] Implementation Option 3: If image 3 As shown, the coalbed methane mixed refrigerant cycle liquefaction process using pressure swing adsorption residual pressure precooling in the secondary cooling process when the temperature of coalbed methane precooling is lower than -60 ° C includes the following steps:

[0032] Step 1, step 2, step 3 and step 4 are respectively the same as step 1, step 2, step 3 and step 4 in embodiment 1;

[0033] 5. The pre-cooled concentrated coalbed methane is cooled to -130°C by the second heat exchanger 14 and cooled to -155°C by the fifth heat exchanger 22 to become low-temperature coalbed methane. The cooling capacity of these two heat exchangers Provided by the mixed refrigerant cycle; the above mixed refrigerant cycle is: a certain amount of mixed refrigerant at normal temperature and pressure is compressed to a medium pressure of 0.8-1.0 MPa by the primary refrigerant compressor 9 and compressed by the secondary refrigerant compressor 11...

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Abstract

A mixed refrigerant re-circulated liquefaction process for precooling coalbed methane (CBM) by residual pressure of pressure swing adsorption (PSA) belongs to the technical field of chemical industry and low temperature. The invention provides an integrated process of adsorption and liquefaction of CBM with high nitrogen content. The process comprises the following steps: before liquefaction, firstly desorbing most nitrogen in the CBM by the PSA process, adopting the residual pressure of adsorption in the above nitrogen to precool the CBM after expanding the residual pressure and liquefying the CBM by the mixed refrigerant re-circulated liquefaction process which is widely applied in the natural gas liquefaction industry. The precooling process of the nitrogen with residual pressure saves the mixed refrigerant flow used for providing cooling capacity, thus reducing the overall power consumption of the system. With the increase of the nitrogen content of the CBM and the residual pressure of adsorption in the nitrogen, the temperature of the precooled CBM gradually decreases, the number of cooling stages of mixed refrigerant cycle can be correspondingly lessened and more power consumption is saved.

Description

technical field [0001] The invention relates to a coalbed gas liquefaction process, in particular to a coalbed gas mixed refrigerant circulation liquefaction process involving high nitrogen content coalbed gas which is precooled by pressure swing adsorption residual pressure. It belongs to the field of chemical industry and low temperature technology. Background technique [0002] Coal bed methane is a kind of coal mine associated gas with methane as the main component, commonly known as "coal mine gas", which belongs to unconventional natural gas. The development and utilization of coalbed methane can not only provide a clean energy with high calorific value, but also prevent mine disasters caused by gas explosions and reduce the emission of methane, a greenhouse gas, which is of great significance to coal mine safety and environmental protection. my country's coalbed methane reserves are abundant, and they are mainly distributed in the economically developed or relatively...

Claims

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Application Information

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IPC IPC(8): F25J3/00B01D53/047
CPCY02P20/10
Inventor 林文胜高婷顾安忠
Owner SHANGHAI JIAO TONG UNIV
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