Technical method for totally recycling mixed cryogens

A process method and a technology of mixing refrigerants, which are applied in the oil and gas industry, can solve the problems of releasing refrigerants, slow restart process, waste of resources, etc., and achieve the effects of reducing pre-cooling time, saving start-up time, and reducing emission waste

Active Publication Date: 2015-12-23
SICHUAN HENGRI GAS ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main components of the mixed refrigerant are nitrogen, methane, ethylene, propane, butane and pentane, among which ethylene, propane, butane and pentane are petrochemical products with high prices, and a large amount of refrigerant will be released during the maintenance of the device. Cause serious waste of resources and increase operating costs
[0004] At present, some patents, such as the patent application "A Method and System for Recycling and Utilizing Mixed Refrigerants" with the publication number CN103383182A, although they have played a role in refrigerant recovery, due to the imperfect process, full recovery cannot be realized, and after parking the machine again After starting up, the refrigerant returned to the system is less than 60% of the original refrigerant, and due to the lack of cooling recovery, the refrigerant needs to be lowered to a low temperature again, and the restart process is slow, which seriously reduces the economical efficiency of the device

Method used

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  • Technical method for totally recycling mixed cryogens
  • Technical method for totally recycling mixed cryogens

Examples

Experimental program
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Effect test

specific Embodiment approach

[0031] figure 1 , figure 2 The full flow of this recycling method is shown. When the liquefaction plant system or the equipment of a certain refrigerant circulation system needs to be overhauled, it needs to be shut down for operation. However, handling of the mixed refrigerant after shutdown is a key issue. The previous practice was to short directly, which caused a lot of economic losses. Based on this, there is a research on this method. The method separates the hot and cold refrigerants into two systems and recovers them separately, meeting the requirement of full recovery of the refrigerants.

[0032] (1) When the machine is shut down for maintenance, the compressor 1 of the refrigerant circulation system stops running. At the inlet of compressor 1, it is a hot and low-pressure refrigerant, where the refrigerant is in a complete gas state, and needs to be pressurized by a small refrigerant compressor 4 to the same pressure as the outlet of compressor 1 of the circula...

Embodiment 1

[0039] After the compressor 1 of the refrigerant circulation system stops running, the hot high-pressure valve 8 is first opened, and the hot high-pressure liquid-phase refrigerant is recovered according to the process described in (3) above. Then judge the pressure of the hot high-pressure gas-phase refrigerant and the pressure in the hot-low pressure refrigerant recovery tank 6. If the pressure of the gas-phase refrigerant is small, it needs to be depressurized through the pressure reducing valve 3 first, and then increased through the small compressor 4. pressure, then enter the hot and low pressure refrigerant recovery tank 6 for storage. If the gas-phase pressure is sufficient to enter the hot and low-pressure refrigerant recovery tank 6 , the bypass valve 7 is opened, and the gas-phase refrigerant directly enters the hot and low-pressure refrigerant recovery tank 6 .

[0040] After the recovery of the hot high-pressure refrigerant is completed, at this time, the pressure...

Embodiment 2

[0045] After the compressor 1 of the refrigerant circulation system stops running, the hot high-pressure valve 8 is first opened, and the hot high-pressure liquid-phase refrigerant is recovered according to the process described in (3) above. Then judge the pressure of the hot high-pressure gas phase refrigerant and the pressure in the hot low pressure refrigerant recovery tank 6, if the gas phase pressure is enough to enter the hot low pressure refrigerant recovery tank 6, then open the bypass valve 7, and the gas phase refrigerant directly enters the hot low pressure refrigerant recovery tank 6. Agent recovery tank 6.

[0046] After the recovery of the hot high-pressure refrigerant is completed, at this time, the pressure of the entire refrigerant circulation system drops. Close the hot high-pressure valve 8, open the hot low-pressure valve 2, and recover the hot and low-pressure refrigerant according to the process described in (1).

[0047] At the same time, the low-tempera...

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Abstract

The invention relates to the technical field of cryogen recycling of the oil-gas industry, in particular to a technical method for totally recycling mixed cryogens. Cold cryogens and hot cryogens are isolated into two systems and recycled respectively. The hot low pressure cryogens are pressurized to be at a high pressure through a small compressor and stored in the high pressure state. The hot high pressure cryogens are recycled to a cryogen recycling tank through a cryogen pump, and after being depressurized, other gas phases are pressurized through a compressor to be recycled. The pressure of the low temperature cryogens is supplemented through a system, the low temperature cryogens are recycled to a low-temperature-cryogen recycling tank and stabilized by controlling the temperature, and when starting is carried out again, the low temperature side of a cold box is directly supplemented with the low temperature cryogens. The pre-cooling time is shortened, and meanwhile the cryogens can be totally recycled.

Description

technical field [0001] The invention relates to the oil and gas industry and the technical field of refrigerant recovery, in particular to a process method for full recovery of mixed refrigerant. Background technique [0002] As a high-quality, efficient and clean fuel, natural gas is being increasingly widely developed and utilized in the fields of energy and transportation. The primary issue in the development and utilization of natural gas is its liquefaction and storage. In recent years, the liquefied natural gas industry has developed rapidly in China, and more and more liquefied natural gas devices have been built and put into operation. Most of the installations that have been built or are under construction use the mixed refrigerant refrigeration process. Mixed refrigerants generally consist of nitrogen, methane, ethylene or ethane, propane or propylene, butane and pentane. When the liquefied natural gas plant is in normal operation, only a small amount of repleni...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F25B45/00
Inventor 苏柯洋
Owner SICHUAN HENGRI GAS ENG CO LTD
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