CN212431493U - Mixed refrigerant compressor set waste heat utilization and circulating refrigeration device - Google Patents

Mixed refrigerant compressor set waste heat utilization and circulating refrigeration device Download PDF

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Publication number
CN212431493U
CN212431493U CN202020309583.7U CN202020309583U CN212431493U CN 212431493 U CN212431493 U CN 212431493U CN 202020309583 U CN202020309583 U CN 202020309583U CN 212431493 U CN212431493 U CN 212431493U
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gas
temperature
refrigerant
cooling module
cooling
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梁威
李忙刚
刘海军
王斌
董博
程正刚
高旭俊
王小宁
刘晓梅
谢辉
赵姗姗
岳庆
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Xian Shaangu Power Co Ltd
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Xian Shaangu Power Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
    • F25J1/0022—Hydrocarbons, e.g. natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0047—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle
    • F25J1/0052—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle by vaporising a liquid refrigerant stream
    • F25J1/0055—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle by vaporising a liquid refrigerant stream originating from an incorporated cascade
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0211—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a multi-component refrigerant [MCR] fluid in a closed vapor compression cycle
    • F25J1/0212—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a multi-component refrigerant [MCR] fluid in a closed vapor compression cycle as a single flow MCR cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0225—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using other external refrigeration means not provided before, e.g. heat driven absorption chillers
    • F25J1/0227—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using other external refrigeration means not provided before, e.g. heat driven absorption chillers within a refrigeration cascade
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0228—Coupling of the liquefaction unit to other units or processes, so-called integrated processes
    • F25J1/0235—Heat exchange integration
    • F25J1/0242—Waste heat recovery, e.g. from heat of compression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
    • F25J1/0262—Details of the cold heat exchange system
    • F25J1/0264—Arrangement of heat exchanger cores in parallel with different functions, e.g. different cooling streams
    • F25J1/0265—Arrangement of heat exchanger cores in parallel with different functions, e.g. different cooling streams comprising cores associated exclusively with the cooling of a refrigerant stream, e.g. for auto-refrigeration or economizer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
    • F25J1/0296—Removal of the heat of compression, e.g. within an inter- or afterstage-cooler against an ambient heat sink
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
    • F25J2220/64—Separating heavy hydrocarbons, e.g. NGL, LPG, C4+ hydrocarbons or heavy condensates in general
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
    • F25J2270/906—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration by heat driven absorption chillers

Abstract

The utility model discloses a mixed refrigerant compressor unit waste heat utilization and circulating refrigeration device, which comprises a high-temperature refrigerant cooling module, a heat energy recovery module, a feed gas cooling module and a high-pressure refrigerant cooling module; the high-temperature refrigerant cooling module is used for cooling the mixed refrigerant through medium-temperature hot water and outputting a normal-temperature high-pressure refrigerant; the heat energy recovery module is used for recovering heat and outputting chilled water and medium-temperature hot water; the raw material gas cooling module is used for inputting raw material gas and chilled water and carrying out heat exchange and temperature reduction on the raw material gas; the high-pressure refrigerant cooling module is used for exchanging heat and cooling chilled water and a normal-temperature high-pressure gas-phase refrigerant to obtain a refrigerated high-pressure refrigerant, and liquefying natural gas after cold quantity balance output. The utility model discloses an effectual cold and heat volume conversion and matching can the effectual high-grade part of retrieving among the process gas waste heat, reduce the compression consumption of liquefying plant and the absorption regeneration energy consumption of molecular sieve system by a wide margin, improve the energy efficiency of device.

Description

Mixed refrigerant compressor set waste heat utilization and circulating refrigeration device
Technical Field
The utility model belongs to natural gas liquefaction and coke oven gas cryrogenic separation field, concretely relates to mixed refrigerant compressor unit waste heat utilization and circulation refrigerating plant.
Background
In recent years, environmental pollution is increasingly serious due to too high coal consumption, and the gradual replacement of coal by using clean energy such as natural gas is one of powerful measures for improving the environmental quality. After 2017, the consumption of natural gas in China is greatly increased under the promotion of the policy of 'changing gas from coal to gas' from top to bottom in China, and the consumption reaches 2803 hundred million m in 20183. LNG (liquefied natural gas) is used as an effective supplement for natural gas, and raw materials such as coke oven gas, coal bed gas and natural gas need to be fully purified and subjected to circulating refrigeration separation in the production process to obtain an LNG product.
In the LNG production process, the energy required by refrigeration liquefaction almost accounts for 70% -85% of the whole device, a large amount of waste heat generated in the refrigerant compression process is discarded, and the heat is discharged into the air, so that not only the effective value cannot be generated, but also extra energy (closed cycle water cooling or air cooling) is required for cooling. When the temperature of the gas entering the refrigerant compressor is higher, the power consumption of the refrigerant compressor is higher, and the temperature of the discharged gas is higher, which has great influence on the production. In actual production, circulating water cooling is mainly adopted, so that a large amount of circulating water and power are consumed, a large amount of waste heat energy and water resources are wasted, and the environment is polluted, which is an important reason for the low energy efficiency at present.
Disclosure of Invention
An object of the utility model is to provide a mixed refrigerant compressor unit waste heat utilization and circulating refrigeration device for waste of resources and the serious problem of energy loss in the LNG production process among the solution prior art.
In order to realize the task, the utility model discloses a following technical scheme:
a mixed refrigerant compressor unit waste heat utilization and circulating refrigeration device comprises a high-temperature refrigerant cooling module, a heat energy recovery module, a raw material gas cooling module and a high-pressure refrigerant cooling module;
the high-temperature refrigerant cooling module is used for cooling a mixed refrigerant through medium-temperature hot water and outputting a normal-temperature high-pressure refrigerant, the high-temperature refrigerant cooling module also comprises a gas-liquid separation unit, the gas-liquid separation unit is used for separating the normal-temperature high-pressure refrigerant output by the high-temperature refrigerant cooling module into a normal-temperature high-pressure liquid-phase refrigerant and a normal-temperature high-pressure gas-phase refrigerant, and the mixed refrigerant comprises the high-temperature high-pressure refrigerant compressed by a compressor and a low-pressure gas-phase refrigerant obtained by the high-pressure refrigerant cooling;
the heat energy recovery module is used for recovering the cold energy of the chilled water after the heat exchange of the raw material gas cooling module, the cold energy of the chilled water after the heat exchange of the high-pressure refrigerant cooling module and the heat energy of the high-temperature hot water after the heat exchange of the high-temperature refrigerant cooling module, and outputting the chilled water and the medium-temperature hot water;
the raw material gas cooling module is used for inputting raw material gas and performing heat exchange and cooling on the chilled water and the raw material gas generated by the heat energy recovery module to obtain refrigerated raw material gas;
the high-pressure refrigerant cooling module is used for exchanging heat and cooling chilled water generated by the heat energy recovery module and normal-temperature high-pressure gas-phase refrigerant obtained by the high-temperature refrigerant cooling module to obtain refrigerated high-pressure refrigerant, balancing cold quantity of refrigerated feed gas generated by the feed gas cooling module and refrigerated high-pressure refrigerant, throttling to obtain low-pressure gas-phase refrigerant and liquefied natural gas, and outputting the liquefied natural gas.
Furthermore, the high-temperature refrigerant cooling module comprises a first mixed refrigerant compressor and a second mixed refrigerant compressor, the output end of the first mixed refrigerant compressor is sequentially connected with the first hot water heat exchanger and the first cooling water heat exchanger, the input end of the second mixed refrigerant compressor is connected with the first cooling water heat exchanger, and the output end of the second mixed refrigerant compressor is sequentially connected with the second hot water heat exchanger and the second cooling water heat exchanger.
Furthermore, the gas-liquid separation unit comprises a first gas-liquid separator arranged between the first cooling water heat exchanger and the second mixed refrigerant compressor, and a second gas-liquid separator arranged between the second cooling water heat exchanger and the high-pressure refrigerant cooling module.
Furthermore, the heat energy recovery module comprises a lithium bromide refrigerating unit, a hot water circulating pump and a chilled water circulating pump, wherein the hot water circulating pump is arranged at the input end of the lithium bromide refrigerating unit, and the chilled water circulating pump is arranged at the output end of the lithium bromide refrigerating unit;
furthermore, the feed gas cooling module comprises a first cooler and a molecular sieve system which are sequentially connected, the input end of the first cooler is connected with the output end of the heat energy recovery module and the feed end of the raw material natural gas, and the output end of the molecular sieve system is respectively connected with the chilled water circulating pump and the high-pressure refrigerant cooling module.
Further, the high-pressure refrigerant cooling module comprises a second cooler, an aluminum plate-fin heat exchanger and a feed gas heavy hydrocarbon separator;
the input end of the second cooler is respectively connected with the output ends of the second gas-liquid separator and the lithium bromide refrigerating unit, and the output end of the second cooler is respectively connected with the chilled water circulating pump and the aluminum plate-fin heat exchanger;
the input end of the aluminum plate-fin heat exchanger is respectively connected with the second cooler, the molecular sieve system and the second gas-liquid separator, and the output end of the aluminum plate-fin heat exchanger is respectively connected with the feed gas heavy hydrocarbon separator, the first mixed refrigerant compressor and the liquefied natural gas output port.
Furthermore, the temperature-changing hot water comprises two temperatures, hot water with the temperature of 65-80 ℃ is adopted at the first hot water heat exchanger and the second hot water heat exchanger, and normal-temperature cooling water with the temperature of 32 ℃ is adopted at the first cooling water heat exchanger and the second cooling water heat exchanger.
Furthermore, hot water connecting pipelines between modules and in the modules adopt cold insulation materials as connecting pipelines of heat insulation materials, chilled water, low-temperature refrigerants and the like.
Compared with the prior art, the utility model has the following technical characteristics:
(1) the utility model discloses be used for current natural gas liquefaction refrigeration field with the compression waste heat of mixed refrigerant compressor unit through reasonable recovery and conversion, not only obtain the utilization with energy such as waste heat of mixed refrigerant compressor unit, also practiced thrift the required mixed refrigerant cyclic compression of natural gas liquefaction refrigeration simultaneously and consumed the energy.
(2) The utility model discloses provide hot water type absorption lithium bromide refrigerating unit after exchanging the process gas waste heat with the compressor through two little pressure differential heat exchangers, the heat absorption formula cooling water set prepares refrigerated water and provides the high pressure gaseous phase refrigerant heat exchanger again and the preceding cooler of feed gas molecular sieve dehydration refrigerates, refrigerant after the refrigeration and feed gas can further reduce the drive consumption of mixed refrigerant compressor unit when the cold balance of aluminium system plate fin heat exchanger, high temperature process gas after the compression with the compressor has carried out the cooling on the one hand, avoid high temperature process gas direct cooling to need consume a large amount of recirculated cooling water, on the other hand is used for driving heat absorption formula cooling water set with absorbent high temperature gas's energy, this kind of cold and hot mode of supplying, a large amount of refrigeration power has been practiced thrift, industrial cost has been practiced thrift.
(3) The utility model discloses refrigerate the feed gas in the cooler before feed gas molecular sieve dehydration, reduce the water content that the feed gas advances the molecular sieve system, improve the adsorption effect of molecular sieve system, effectively reduce on the regeneration energy consumption basis of molecular sieve, can wholly prolong the life cycle of device molecular sieve adsorbent, the operation consumption of reducing mechanism further improves the technical equipment level of device.
Drawings
Fig. 1 is a schematic diagram of the connection of the modules of the present invention;
fig. 2 is a schematic diagram of the device connection of the present invention.
The various reference numbers in the drawings have the meanings given below: 101-mixed refrigerant compressor unit, 102-first hot water heat exchanger, 103-first cooling water heat exchanger, 104-first gas-liquid separator, 105-first hot water heat exchanger, 106-second cooling water heat exchanger, 107-second gas-liquid separator, 108-first cooler, 109-second cooler, 110-aluminum plate-fin heat exchanger, 111-raw gas heavy hydrocarbon separator, 112-lithium bromide refrigerating unit, 113-hot water circulating pump, 114-chilled water circulating pump; 101-1-a first mixed refrigerant compressor, 101-2-a second mixed refrigerant compressor.
The following detailed description of the present invention is provided in connection with the accompanying drawings and the detailed description of the invention.
Detailed Description
The following embodiments of the present invention are given, and it should be noted that the present invention is not limited to the following embodiments, and all the equivalent transformations made on the basis of the technical solution of the present application all fall into the protection scope of the present invention.
A mixed refrigerant compressor unit waste heat utilization and circulating refrigeration device comprises a high-temperature refrigerant cooling module, a heat energy recovery module, a raw material gas cooling module and a high-pressure refrigerant cooling module;
the high-temperature refrigerant cooling module is used for cooling the mixed refrigerant through medium-temperature hot water and outputting a normal-temperature high-pressure refrigerant; the function is as follows: the high-pressure high-temperature refrigerant compressed by the compressor is cooled to normal temperature to carry out the next-stage compression or output system, so that the purpose of improving the compression efficiency in the compression process is achieved.
The high-temperature refrigerant cooling module also comprises a gas-liquid separation unit which is used for separating the normal-temperature high-pressure refrigerant output by the high-temperature refrigerant cooling module into a normal-temperature high-pressure liquid-phase refrigerant and a normal-temperature high-pressure gas-phase refrigerant, and the mixed refrigerant comprises the high-temperature high-pressure refrigerant compressed by the compressor and a low-pressure gas-phase refrigerant obtained by refrigerating and throttling the high-pressure refrigerant cooling module in the aluminum plate-fin heat exchanger; the function is as follows: separating high-boiling-point condensate possibly carried in normal-temperature mixed refrigerant from an aluminum plate-fin heat exchanger or high-pressure mixed refrigerant cooled after being compressed by a compressor, thereby achieving the purpose of protecting a compressor unit and a pipeline system for stable conveying;
the heat energy recovery module is used for recovering the cold energy of the chilled water after the heat exchange of the raw material gas cooling module, the cold energy of the chilled water after the heat exchange of the high-pressure refrigerant cooling module and the heat energy of the high-temperature hot water after the heat exchange of the high-temperature refrigerant cooling module, and outputting the chilled water and the medium-temperature hot water;
the function is as follows: high-temperature hot water obtained by taking heat from a hot water heat exchanger of the high-temperature refrigerant and the medium-temperature hot water is input into a lithium bromide unit, so that the aim of preparing cold energy by using waste heat energy is fulfilled;
the raw material gas cooling module is used for inputting raw material gas and performing heat exchange and cooling on the chilled water and the raw material gas generated by the heat energy recovery module to obtain refrigerated raw material gas;
the function is as follows: cooling the chilled water generated by the system and the raw material gas before the molecular sieve to remove saturated water in the raw material gas, reduce the water content of the raw material gas entering the molecular sieve system and achieve the purpose of reducing the dehydration load and the regeneration load of the molecular sieve system;
the high-pressure refrigerant cooling module is used for exchanging heat and cooling chilled water generated by the heat energy recovery module and a normal-temperature high-pressure gas-phase refrigerant obtained by the high-temperature refrigerant cooling module to obtain a refrigerated high-pressure refrigerant, balancing cold quantity of a refrigerated feed gas generated by the feed gas cooling module and the refrigerated high-pressure refrigerant, throttling to obtain a low-pressure gas-phase refrigerant and liquefied natural gas, and outputting the liquefied natural gas;
the function is as follows: the chilled water generated by the system exchanges heat with the normal-temperature high-pressure gas-phase refrigerant, so that the purposes of reducing the temperature of the high-pressure gas-phase refrigerant and reducing the cooling capacity required by the aluminum plate-fin heat exchanger for cooling the feed gas are achieved.
Specifically, the high-temperature refrigerant cooling module comprises a first mixed refrigerant compressor 101-1 and a second mixed refrigerant compressor 101-2, the output end of the first mixed refrigerant compressor 101-1 is sequentially connected with a first hot water heat exchanger 102 and a first cooling water heat exchanger 103, the input end of the second mixed refrigerant compressor 101-2 is connected with the first cooling water heat exchanger 103, and the output end of the second mixed refrigerant compressor 101-2 is sequentially connected with a second hot water heat exchanger 105 and a second cooling water heat exchanger 106.
Specifically, the gas-liquid separation unit includes a first gas-liquid separator 104 disposed between the first cooling water heat exchanger 103 and the second mixed refrigerant compressor 101-2, and further includes a second gas-liquid separator 107 disposed between the second cooling water heat exchanger 106 and the high-pressure refrigerant cooling module.
Specifically, the heat energy recovery module comprises a lithium bromide refrigerating unit 112, a hot water circulating pump 113 and a chilled water circulating pump 114, wherein the hot water circulating pump 113 is arranged at the input end of the lithium bromide refrigerating unit 112, and the chilled water circulating pump 114 is arranged at the output end of the lithium bromide refrigerating unit 112;
specifically, the feed gas cooling module comprises a first cooler 109 and a molecular sieve system which are connected in sequence, the input end of the first cooler 109 is connected with the output end of the heat energy recovery module and the feed end of the feed natural gas, and the output end of the molecular sieve system is respectively connected with a chilled water circulating pump 114 and a high-pressure refrigerant cooling module.
Specifically, the high-pressure refrigerant cooling module comprises a second cooler 108, an aluminum plate-fin heat exchanger 110 and a feed gas heavy hydrocarbon separator 111;
the input end of the second cooler 108 is respectively connected with the output ends of the second gas-liquid separator 107 and the lithium bromide refrigerating unit 112, and the output end of the second cooler 108 is respectively connected with the chilled water circulating pump 114 and the aluminum plate-fin heat exchanger 110;
the input end of the aluminum plate-fin heat exchanger 110 is respectively connected with the second cooler 108, the molecular sieve system and the second gas-liquid separator 107, and the output end of the aluminum plate-fin heat exchanger 110 is respectively connected with the feed gas heavy hydrocarbon separator 111, the first mixed refrigerant compressor 101-1 and the liquefied natural gas output port.
Preferably, the temperature-changing hot water has two temperatures, hot water with a temperature of 65-80 ℃ is adopted at the first hot water heat exchanger 102 and the second hot water heat exchanger 105, and normal-temperature cooling water with a temperature of 32 ℃ is adopted at the first cooling water heat exchanger 103 and the second cooling water heat exchanger 106. The heat exchange hot water is a hot water medium, the water is supplemented from normal temperature soft water, the water enters a small pressure difference heat exchanger of each stage of compressor after being boosted by a connected water pump and system temperature rise to exchange heat with high temperature refrigerant gas, the water with the temperature raised after heat exchange is sent into a lithium bromide refrigerating unit through a pipeline and a control valve, the generated chilled water is respectively communicated with a dehydration cooler in front of a molecular sieve system and a high pressure gas phase refrigerant heat exchanger through the pipeline and the control valve, the high pressure gas phase refrigerant heat exchanger and the dehydration cooler of the molecular sieve system are small pressure difference heat exchangers, and the chilled water returns to the lithium bromide unit for circulating refrigeration after providing cold energy.
Specifically, hot water connecting pipelines between modules and in the modules adopt heat insulation materials, freezing water, low-temperature refrigerants and other connecting pipelines adopt cold insulation materials, heat loss and cold loss of the system are reduced, and energy utilization efficiency is improved.
Specifically, the refrigeration system of the aluminum plate-fin heat exchanger further cools and throttles the high-pressure gas-phase refrigerant and the high-pressure liquid-phase refrigerant, provides the cold energy required by the liquefaction and cooling of the raw material gas into the LNG, mixes the low-pressure mixed refrigerant which is reheated after providing the cold energy, and then circulates the mixed refrigerant to the inlet of the mixed refrigerant compressor unit C301 for circulation.
The utility model discloses a work flow does: when the high-temperature cryogen process gas of the compressor passes through the interstage cooling and the final stage cooling E-303, firstly, a small pressure difference heat exchanger and hot water with the temperature of 65-80 ℃ are adopted for heat exchange and heat extraction, the temperature of the process gas is reduced, and then the process gas after heat extraction is continuously cooled by a conventional circulating cooling water heat exchanger. The hot water after being heated by the small differential pressure heat exchanger is heated to 75-90 ℃, the high-temperature hot water is converged and then enters a hot water type absorption lithium bromide refrigerator unit to provide a heat source to prepare 7-15 ℃ chilled water, the high-temperature hot water is cooled to 65-80 ℃ after providing heat in the lithium bromide refrigerator unit, and the high-temperature hot water returns to an interstage small differential pressure heat exchanger and a final stage small differential pressure heat exchanger of a compressor to circularly and continuously heat. The method comprises the steps that chilled water with the temperature of 7-15 ℃ prepared by a lithium bromide unit is respectively sent to a high-pressure gas-phase refrigerant heat exchanger and a cooler before dehydration of a feed gas molecular sieve to cool a high-pressure gas-phase refrigerant and the feed gas, the cooled high-pressure gas-phase refrigerant and the cooled feed gas respectively enter an aluminum plate-fin heat exchanger through different runners, after system cold quantity is balanced, a low-pressure gas-phase refrigerant returns to an inlet of a mixed refrigerant compressor unit, and when the cold quantity of the refrigerated refrigerant and the cooled feed gas is balanced in the aluminum plate-fin heat exchanger, the driving power consumption of the mixed refrigerant compressor unit can be.
The utility model discloses a mixed refrigerant compressor interstage and last stage discharge's high temperature cryogen process gas reduces the temperature to 40 ℃ through multistage heat transfer device, wherein carries out recycle with the high-grade heat (more than or equal to 75 ℃) in the high temperature cryogen process gas, then turns into high temperature hot water (75 ℃ -90 ℃) with this high-grade heat and carries out the refrigerated water and prepare, send to hot-water pump and heat exchanger behind the high temperature hot water provides the heat and circulate and heat up after becoming medium temperature hot water (65 ℃ -80 ℃). The whole hot water circulating system pipeline is insulated by adopting an insulation material, so that the heat loss of the system is reduced, and the heat utilization efficiency is improved. Therefore, the high-temperature gas discharged by the mixed refrigerant compressor is subjected to waste heat recovery, the consumption of circulating cooling water is reduced due to the use of circulating hot water, the power consumption and the treatment capacity of the circulating cooling water of the whole device are reduced, and a large amount of circulating water and power resources are saved.
Examples
Take a 100 ten thousand square/day LNG liquefaction plant of a certain LNG liquefaction plant as an example:
serial number Item of equipment Quantity (table) Total Power (kW)
1 Raw material gas compressor unit 1 2000
2 Original mixed refrigerant compressor unit 1 13500
3 Original dehydration molecular sieve heater 1 600
4 Newly-added lithium bromide unit 1 10
5 Circulating pump for increasing hot water 2 45
6 Newly-added chilled water circulating pump 2 70
The Aspen software is used for carrying out numerical simulation calculation and heat exchanger model selection calculation on the thermal data of the high-temperature process gas waste heat of the mixed refrigerant compressor unit, as shown in figure 1, the total amount of the waste heat available after the system is balanced and the specific parameters of each module are obtained through analysis and calculation.
The 100-ten-thousand-square/day LNG liquefying device can save energy by 625-850 kw on the basis of current operation. The method comprises the steps that a small-pressure-difference heat exchanger is used for extracting waste heat from a compressor unit cooler through medium-temperature hot water to prepare high-temperature hot water, after the high-temperature hot water is prepared into chilled water through a lithium bromide unit, cold energy is transmitted to a high-pressure gas-phase refrigerant and a raw material gas through different coolers, and after cold energy balance is carried out through an aluminum plate-fin heat exchanger, the power consumption of a mixed refrigerant compressor unit can be effectively reduced by about 650-900 kw; the newly added equipment increases the power consumption of a circulating water pump and the like by about 125 kw; after the low-temperature waste heat is used for dehydrating the raw material gas before the molecular sieve, the adsorption effect of a molecular sieve system can be greatly improved, and the regeneration energy consumption of the molecular sieve is effectively reduced by 15-20%, which is about 110 kw.
The utility model discloses implement the back, behind the adsorption effect who improves the molecular sieve system, can prolong the life cycle of device molecular sieve adsorbent simultaneously on current operation basis, the operation consumption of reducing device further improves the technical equipment level of device.

Claims (8)

1. The mixed refrigerant compressor unit waste heat utilization and circulating refrigeration device is characterized by comprising a high-temperature refrigerant cooling module, a heat energy recovery module, a raw material gas cooling module and a high-pressure refrigerant cooling module;
the high-temperature refrigerant cooling module is used for cooling a mixed refrigerant through medium-temperature hot water and outputting a normal-temperature high-pressure refrigerant, the high-temperature refrigerant cooling module also comprises a gas-liquid separation unit, the gas-liquid separation unit is used for separating the normal-temperature high-pressure refrigerant output by the high-temperature refrigerant cooling module into a normal-temperature high-pressure liquid-phase refrigerant and a normal-temperature high-pressure gas-phase refrigerant, and the mixed refrigerant comprises the high-temperature high-pressure refrigerant compressed by a compressor and a low-pressure gas-phase refrigerant obtained by refrigerating and throttling the high-pressure refrigerant cooling module in the aluminum plate-;
the heat energy recovery module is used for recovering the cold energy of the chilled water after the heat exchange of the raw material gas cooling module, the cold energy of the chilled water after the heat exchange of the high-pressure refrigerant cooling module and the heat energy of the high-temperature hot water after the heat exchange of the high-temperature refrigerant cooling module, and outputting the chilled water and the medium-temperature hot water;
the raw material gas cooling module is used for inputting raw material gas and performing heat exchange and cooling on the chilled water and the raw material gas generated by the heat energy recovery module to obtain refrigerated raw material gas;
the high-pressure refrigerant cooling module is used for exchanging heat and cooling chilled water generated by the heat energy recovery module and normal-temperature high-pressure gas-phase refrigerant obtained by the high-temperature refrigerant cooling module to obtain refrigerated high-pressure refrigerant, balancing cold quantity of refrigerated feed gas generated by the feed gas cooling module and refrigerated high-pressure refrigerant, throttling to obtain low-pressure gas-phase refrigerant and liquefied natural gas, and outputting the liquefied natural gas.
2. The mixed refrigerant compressor unit waste heat utilization and circulation refrigerating device as claimed in claim 1, wherein the high temperature refrigerant cooling module comprises a first mixed refrigerant compressor (101-1) and a second mixed refrigerant compressor (101-2), the output end of the first mixed refrigerant compressor (101-1) is connected with a first hot water heat exchanger (102) and a first cooling water heat exchanger (103) in sequence, the input end of the second mixed refrigerant compressor (101-2) is connected with a first cooling water heat exchanger (103), and the output end of the second mixed refrigerant compressor (101-2) is connected with a second hot water heat exchanger (105) and a second cooling water heat exchanger (106) in sequence.
3. The mixed refrigerant compressor train waste heat utilization and circulation refrigeration device according to claim 2, wherein the gas-liquid separation unit comprises a first gas-liquid separator (104) disposed between the first cooling water heat exchanger (103) and the second mixed refrigerant compressor (101-2), and further comprises a second gas-liquid separator (107) disposed between the second cooling water heat exchanger (106) and the high pressure refrigerant cooling module.
4. The mixed refrigerant compressor unit waste heat utilization and circulation refrigerating device as claimed in claim 3, wherein the heat energy recovery module comprises a lithium bromide refrigerating unit (112), a hot water circulating pump (113) and a chilled water circulating pump (114), the hot water circulating pump (113) is arranged at an input end of the lithium bromide refrigerating unit (112), and the chilled water circulating pump (114) is arranged at an output end of the lithium bromide refrigerating unit (112).
5. The mixed refrigerant compressor unit waste heat utilization and circulation refrigerating device as claimed in claim 4, wherein the raw material gas cooling module comprises a first cooler (109) and a molecular sieve system which are connected in sequence, an input end of the first cooler (109) is connected with an output end of the heat energy recovery module and a raw material natural gas feed end, and an output end of the molecular sieve system is respectively connected with the chilled water circulation pump (114) and the high-pressure refrigerant cooling module.
6. The mixed refrigerant compressor train waste heat utilization and circulation refrigeration unit of claim 5, wherein the high pressure refrigerant cooling module comprises a second cooler (108), an aluminum plate-fin heat exchanger (110), and a feed gas heavy hydrocarbon separator (111);
the input end of the second cooler (108) is respectively connected with the output ends of the second gas-liquid separator (107) and the lithium bromide refrigerating unit (112), and the output end of the second cooler (108) is respectively connected with the chilled water circulating pump (114) and the aluminum plate-fin heat exchanger (110);
the input end of the aluminum plate-fin heat exchanger (110) is respectively connected with a second cooler (108), a molecular sieve system and a second gas-liquid separator (107), and the output end of the aluminum plate-fin heat exchanger (110) is respectively connected with a feed gas heavy hydrocarbon separator (111), a first mixed refrigerant compressor (101-1) and a liquefied natural gas output port.
7. The mixed refrigerant compressor unit waste heat utilization and circulation refrigeration device according to claim 2, wherein medium temperature hot water of 65 to 80 ℃ is used at the first hot water heat exchanger (102) and the second hot water heat exchanger (105), and normal temperature cooling water of 32 ℃ is used at the first cooling water heat exchanger (103) and the second cooling water heat exchanger (106).
8. The mixed refrigerant compressor unit waste heat utilization and circulation refrigerating device as claimed in claim 1, wherein the hot water connection pipes between the respective modules and inside the modules are made of heat insulating material, and the connection pipes of chilled water and low temperature refrigerant are made of cold insulating material.
CN202020309583.7U 2020-03-12 2020-03-12 Mixed refrigerant compressor set waste heat utilization and circulating refrigeration device Active CN212431493U (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117450681A (en) * 2023-12-22 2024-01-26 上海优华系统集成技术股份有限公司 Cold and heat combined supply system and method based on compressor compression heat full recovery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117450681A (en) * 2023-12-22 2024-01-26 上海优华系统集成技术股份有限公司 Cold and heat combined supply system and method based on compressor compression heat full recovery
CN117450681B (en) * 2023-12-22 2024-03-26 上海优华系统集成技术股份有限公司 Cold and heat combined supply system and method based on compressor compression heat full recovery

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