CN210267883U - Low-energy-consumption combined type natural gas liquefaction peak regulation system - Google Patents

Low-energy-consumption combined type natural gas liquefaction peak regulation system Download PDF

Info

Publication number
CN210267883U
CN210267883U CN201920937600.9U CN201920937600U CN210267883U CN 210267883 U CN210267883 U CN 210267883U CN 201920937600 U CN201920937600 U CN 201920937600U CN 210267883 U CN210267883 U CN 210267883U
Authority
CN
China
Prior art keywords
heat exchanger
outlet
inlet
gas
nitrogen
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201920937600.9U
Other languages
Chinese (zh)
Inventor
张引弟
薛鹏
刘梅梅
王珂
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yangtze University
Original Assignee
Yangtze University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yangtze University filed Critical Yangtze University
Priority to CN201920937600.9U priority Critical patent/CN210267883U/en
Application granted granted Critical
Publication of CN210267883U publication Critical patent/CN210267883U/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • F25J1/0032—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 the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
    • F25J1/0035—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 the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by gas expansion with extraction of work
    • F25J1/0037—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 the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by gas expansion with extraction of work of a return stream
    • 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
    • F25J1/0032—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 the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
    • F25J1/004—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 the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by flash gas recovery
    • 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
    • F25J1/005—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 expansion of a gaseous refrigerant stream with extraction of work
    • 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
    • F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
    • F25J1/007—Primary atmospheric gases, mixtures thereof
    • F25J1/0072—Nitrogen
    • 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
    • F25J1/0201—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 only internal refrigeration means, i.e. without external refrigeration
    • 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
    • F25J1/0203—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 single-component refrigerant [SCR] fluid in a closed vapor compression cycle
    • F25J1/0204—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 single-component refrigerant [SCR] fluid in a closed vapor compression cycle as a single flow SCR 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
    • F25J1/0228—Coupling of the liquefaction unit to other units or processes, so-called integrated processes
    • F25J1/0232—Coupling of the liquefaction unit to other units or processes, so-called integrated processes integration within a pressure letdown station of a high pressure pipeline system
    • 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
    • F25J1/0244—Operation; Control and regulation; Instrumentation
    • F25J1/0245—Different modes, i.e. 'runs', of operation; Process control

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

The utility model discloses a low-energy consumption combined natural gas liquefaction peak regulation system, which comprises a precooling heat exchanger, a flow distributor, a main heat exchanger, a natural gas expander, a first mixer, a gas-liquid separator and an LNG pressure storage tank; the precooling heat exchanger is provided with a first air inlet, a first air outlet of the precooling heat exchanger is connected with an air inlet of the flow distributor, a first air outlet of the flow distributor is connected with a first inlet of the main heat exchanger, a first outlet of the main heat exchanger is connected with an inlet of the gas-liquid separator, a flash steam outlet of the gas-liquid separator is connected with a first feed inlet of the first mixer, and an LNG outlet of the gas-liquid separator is connected with an LNG inlet of the LNG pressure storage tank. The utility model discloses a system make full use of the surplus pressure energy of trunk line pipeline, realized the zero energy consumption peak regulation under the low liquefaction rate condition of natural gas.

Description

Low-energy-consumption combined type natural gas liquefaction peak regulation system
Technical Field
The utility model relates to a liquefied natural gas's technical field, concretely relates to low energy consumption combined type natural gas liquefaction peak shaving system.
Background
With the increasingly prominent problem of air pollution, the demand of China for clean energy is more urgent. Natural gas is a clean energy source which can be utilized in a large scale, the main transportation mode is to adopt a pipeline for long-distance transportation, and the construction of the natural gas pipeline can assist the economic development of China. The design of long distance gas transmission pipeline needs to satisfy the minimum gas supply pressure requirement of the users along the line, and because the gas supply pressure of each user has difference, when distributing and transmitting natural gas to the users with lower pressure requirement, a difference value is generated between the actual gas supply pressure and the minimum gas supply required pressure. Generally, the natural gas is directly throttled and depressurized through the pressure regulating pry at the branch transmission station, and then enters the urban gas transmission and distribution system after being subjected to pressure regulation and odorization at the urban gate station, so that the following defects exist: firstly, the pressure of the natural gas is directly regulated, so that the waste of pressure energy is caused; and secondly, the pipeline gas storage amount is limited, the gas storage peak regulation has geographical condition limitation, and for a main pipeline of an unconditionally available gas storage, a natural gas liquefaction and regasification peak regulation mode is required to be adopted in order to balance the supply and demand of gas transmission of a pipeline.
At present, the liquefaction methods which are applied in China mainly comprise:
(1) the cascade type liquefaction process is characterized in that natural gas is cooled step by utilizing the refrigeration temperatures of various pure hydrocarbon components, and liquefaction is finally realized, the specific power consumption of the process is between 0.38kWh and 0.45kWh, the process has the advantages of low ① energy consumption, no component proportion problem because ② each-stage refrigerant is a pure substance, mature ③ technology and stable operation, and has the defects of more ① units, complex flow, more ② accessory equipment, needing equipment for specially producing and storing various refrigerants, complex ③ pipeline and control system and inconvenient maintenance.
(2) A mixed refrigerant liquefaction process with propane precooling, namely, a variable-temperature gasification working medium is prepared by adopting a plurality of hydrocarbons and light components, so that the mixed refrigerant has continuous and variable refrigeration temperature under the same pressure, and the process has the advantages of less ① unit equipment, simpler process, less investment, convenient management of ②, capability of partially or completely obtaining or supplementing ③ mixed refrigerant components from natural gas, high energy consumption of ①, 10-20 percent higher than that of a cascade process, difficult reasonable distribution of ② mixed refrigerant, difficulty in calculation of ③ process for providing reliable balance data of each component, and difficulty in calculation;
(3) the differential pressure type direct expansion liquefaction process directly adopts natural gas as a refrigeration working medium, and has the advantages of simple ① flow, flexible adjustment, reliable work, easy start, easy operation and the like, and has the defects of low liquefaction rate of the ① flow, difficulty in realizing large-scale liquefaction, and limitation of a low-pressure user on the ② flow;
(4) the nitrogen expansion refrigeration liquefaction process adopts nitrogen or a mixture of nitrogen and methane as a refrigeration working medium, and has the advantages that ① refrigeration cycle is closed cycle, refrigerant is isolated from natural gas, ② liquefaction rate is high, device size is small, operation is convenient, flexibility is strong, and the defects of ① specific energy consumption is higher and is higher than that of a cascade type liquefaction process by more than 70%.
In view of the above technical current situation, it is necessary to provide a system with low energy consumption, adjustable liquefaction rate, moderate equipment investment, and applicability to the condition without gas storage, so as to reduce peak shaving cost and improve peak shaving adaptability of main pipeline.
Disclosure of Invention
An object of the utility model is to overcome above-mentioned background art not enough, and provide a low energy consumption combined type natural gas liquefaction peak shaving system, this system make full use of the surplus pressure energy of main line pipeline, realized the zero energy consumption peak shaving under the low liquefaction rate condition of natural gas.
In order to achieve the above object, the utility model provides a low energy consumption combined type natural gas liquefaction peak shaving system, including precooling heat exchanger, flow distributor, main heat exchanger, natural gas expander, first blender, vapour and liquid separator and LNG pressure storage tank;
the precooling heat exchanger is provided with a first air inlet, a first air outlet of the precooling heat exchanger is connected with an air inlet of the flow distributor, a first air outlet of the flow distributor is connected with a first inlet of the main heat exchanger, a first outlet of the main heat exchanger is connected with an inlet of the gas-liquid separator, a flash steam outlet of the gas-liquid separator is connected with a first feed port of the first mixer, and an LNG outlet of the gas-liquid separator is connected with an LNG inlet of the LNG pressure storage tank;
a second gas outlet of the flow distributor is connected with a second inlet of the main heat exchanger through a natural gas expander, and a second outlet of the main heat exchanger is connected with a second feeding hole of the first mixer; and a discharge hole of the first mixer is connected with a second air inlet of the precooling heat exchanger, and a second air outlet is formed in the precooling heat exchanger.
In the technical scheme, the device also comprises a nitrogen expansion machine, a circulating nitrogen compressor, a water cooler and a nitrogen buffer tank, wherein the nitrogen buffer tank is provided with a nitrogen injection port, and a nitrogen outlet of the nitrogen buffer tank is connected with a nitrogen inlet of the circulating nitrogen compressor;
and a compressed nitrogen outlet of the circulating nitrogen compressor is connected with a third air inlet of the precooling heat exchanger through a water cooler, a third air outlet of the precooling heat exchanger is connected with a third inlet of the main heat exchanger through a nitrogen expansion machine, a third outlet of the main heat exchanger is connected with a fourth air inlet of the precooling heat exchanger, and a fourth air outlet of the precooling heat exchanger is connected with an air inlet of the nitrogen buffer tank.
In the technical scheme, the LNG mixing device further comprises a second mixer and an air temperature gasifier, a gas outlet of the LNG pressure storage tank is connected with a first inlet of the second mixer, a liquid outlet of the LNG pressure storage tank is connected with a second inlet of the second mixer, a mixture outlet of the second mixer is connected with an inlet of the air temperature gasifier, and an outlet of the air temperature gasifier is connected with a downstream pipeline.
In the above technical scheme, a throttle valve is arranged on a pipeline between the first outlet of the main heat exchanger and the inlet of the gas-liquid separator.
Compared with the prior art, the utility model has the advantages of as follows:
firstly, the utility model makes full use of the surplus pressure energy of the main pipeline, and realizes the peak regulation of zero energy consumption under the condition of low liquefaction rate (less than 10%) of the natural gas;
secondly, the utility model adopts the nitrogen expansion cycle as the supplement source of the refrigerating output, and the circulating refrigerating output can be adjusted according to the distribution of the stock flow to be liquefied, thereby realizing the peak regulation of low energy consumption under the condition of high liquefaction rate (10-50%) of the natural gas;
thirdly, the utility model discloses a refrigerant is nitrogen gas, and the nitrogen gas source is wide, and the storage of liquid nitrogen, nitrogen gas can not cause greenhouse effect and environmental pollution with the emission, compares the alkane cold medium and has the characteristic of clean environmental protection.
Drawings
FIG. 1 is a schematic structural diagram of a low energy consumption combined natural gas liquefaction peak shaving system according to an embodiment;
in the figure, 1-precooling heat exchanger, 1.1-first gas inlet, 1.2-first gas outlet, 1.3-third gas inlet, 1.4-third gas outlet, 1.5-second gas inlet, 1.6-second gas outlet, 1.7-fourth gas inlet, 1.8-fourth gas outlet, 2-flow distributor, 2.1-gas inlet, 2.2-first gas outlet, 2.3-second gas outlet, 3-main heat exchanger, 3.1-first inlet, 3.2-first outlet, 3.3-second inlet, 3.4-second outlet, 3.5-third inlet, 3.6-third outlet, 4-nitrogen expander, 5-natural gas expander, 6-first mixer, 6.1-first feed inlet, 6.2-second feed inlet, 6.3-discharge outlet, 7-circulating nitrogen compressor, 7.1-nitrogen inlet, 7.2-compressed nitrogen outlet, 8-water cooler, 9-throttle valve, 10-gas-liquid separator, 10.1-inlet, 10.2-flash steam outlet, 10.3-LNG outlet, 11-LNG pressure storage tank, 11.1-LNG inlet, 11.2-gas outlet, 11.3-liquid outlet, 12-second mixer, 12.1-first inlet, 12.2-second inlet, 12.3-mixture outlet, 13-air temperature gasifier, 13.1-inlet, 13.2-outlet, 14-nitrogen buffer tank, 14.1-nitrogen injection port, 14.2-nitrogen outlet and 14.3-gas inlet.
Detailed Description
The present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. While the advantages of the invention will be apparent and readily appreciated by the description.
The utility model discloses a low energy consumption combined type natural gas liquefaction peak shaving system, including precooling heat exchanger 1, flow distributor 2, main heat exchanger 3, natural gas expander 5, first blender 6, vapour and liquid separator 10 and LNG pressure storage tank 11; the pre-cooling heat exchanger 1 is provided with a first air inlet 1.1, a first air outlet 1.2 of the pre-cooling heat exchanger 1 is connected with a gas inlet 2.1 of a flow distributor 2, a first gas outlet 2.2 of the flow distributor 2 is connected with a first inlet 3.1 of a main heat exchanger 3, a first outlet 3.2 of the main heat exchanger 3 is connected with an inlet 10.1 of a gas-liquid separator 10, a throttle valve 9 is arranged on a pipeline between the first outlet 3.2 of the main heat exchanger 3 and an inlet 10.1 of the gas-liquid separator 10, a flash steam outlet 10.2 of the gas-liquid separator 10 is connected with a first feed inlet 6.1 of a first mixer 6, and an LNG outlet 10.3 of the gas-liquid separator 10 is connected with an LNG inlet 11.1 of an LNG pressure storage tank 11; a second gas outlet 2.3 of the flow distributor 2 is connected with a second inlet 3.3 of the main heat exchanger 3 through a natural gas expander 5, and a second outlet 3.4 of the main heat exchanger 3 is connected with a second feeding hole 6.2 of the first mixer 6; and a discharge port 6.3 of the first mixer 6 is connected with a second air inlet 1.5 of the precooling heat exchanger 1, and a second air outlet 1.6 is arranged on the precooling heat exchanger 1.
In the technical scheme, the device further comprises a nitrogen expansion machine 4, a circulating nitrogen compressor 7, a water cooler 8 and a nitrogen buffer tank 14, wherein the nitrogen buffer tank 14 is provided with a nitrogen injection port 14.1, and a nitrogen outlet 14.2 of the nitrogen buffer tank 14 is connected with a nitrogen inlet 7.1 of the circulating nitrogen compressor 7; a compressed nitrogen outlet 7.2 of the circulating nitrogen compressor 7 is connected with a third air inlet 1.3 of the precooling heat exchanger 1 through a water cooler 8, a third air outlet 1.4 of the precooling heat exchanger 1 is connected with a third inlet 3.5 of the main heat exchanger 3 through a nitrogen expansion machine 4, a third outlet 3.6 of the main heat exchanger 3 is connected with a fourth air inlet 1.7 of the precooling heat exchanger 1, and a fourth air outlet 1.8 of the precooling heat exchanger 1 is connected with an air inlet 14.3 of the nitrogen buffer tank 14.
In the above technical solution, the LNG storage tank comprises a second mixer 12 and an air temperature gasifier 13, a gas outlet 11.2 of the LNG pressure storage tank 11 is connected with a first inlet 12.1 of the second mixer 12, a liquid outlet 11.3 of the LNG pressure storage tank 11 is connected with a second inlet 12.2 of the second mixer 12, a mixture outlet 12.3 of the second mixer 12 is connected with an inlet 13.1 of the air temperature gasifier 13, and an outlet 13.2 of the air temperature gasifier 13 is connected with a downstream pipeline.
The utility model discloses the application method of system, including following three kinds of operating modes:
the first working condition is as follows: if the gas storage capacity of the natural gas pipeline section is neglected, when the upstream gas supply quantity of the main pipeline is not more than 1.1 times of the downstream gas consumption quantity (Q)Downstream air＜QUpstream supply of gasQ is less than or equal to 1.11 timesDownstream air) And starting the low liquefaction load peak regulation method, wherein the nitrogen refrigeration cycle does not work. Natural gas with the temperature of 20 ℃ and the pressure of 5.3MPa from a gas transmission trunk line is pre-cooled to the temperature of minus 45.4 ℃ by a pre-cooling heat exchanger 1 and is divided into two flows by a flow distributor 2, wherein 16 percent of the flow is used as a flow to be liquefied, and the rest 84 percent of the flow is used as a refrigerating flow.
Condensing (-75.94 ℃) the stock flow to be liquefied through a main heat exchanger 3, decompressing the liquefied stock flow to the lowest pressure (2.5MPa, -98.61 ℃) of user gas supply through a throttle valve 9, generating flash evaporation gas in the process, and separating LNG and the flash evaporation gas through a gas-liquid separator 10; the refrigeration strand flows through a natural gas expander 5 to expand to generate low-temperature low-pressure (2.5 MPa-79.6 ℃) natural gas, the pressure of the natural gas needs to meet the lowest pressure (2.5MPa) of gas supply of a user, and the natural gas enters a main heat exchanger 3 to exchange heat to obtain low-temperature low-pressure natural gas (2.5 MPa-64.18 ℃);
LNG is sent into an LNG pressure storage tank 11 to be stored, flash steam and low-temperature and low-pressure natural gas (2.5MPa and-64.18 ℃) subjected to heat exchange through a main heat exchanger 3 form confluence (2.5MPa and-66.78 ℃) in a mixer 6, and finally the mixed gas is sent into a precooling heat exchanger 1 to provide cold energy for the natural gas from a trunk line, and simultaneously the mixed gas is reheated to normal-temperature natural gas (2.5MPa and 16.95 ℃). The liquefaction rate in this case was 9.65%, with almost no power consumption.
The second working condition is as follows: when the upstream air supply amount of the main pipeline is 1.1 times larger than the downstream air consumption amount and is not more than 2 times of the downstream air consumption amount (1.11 times Q)Downstream air＜QUpstream supply of gasQ is less than or equal to 2 timesDownstream air) And starting a high liquefaction load peak regulation method, namely starting a nitrogen refrigeration cycle. Natural gas (20 ℃ and 5.3MPa) from a gas transmission trunk line is pre-cooled to (-45.4 ℃) through a pre-cooling heat exchanger 1, and is divided into two flows through a flow distributor 2, wherein 68% of the flow serves as a flow to be liquefied, and the rest 32% of the flow serves as a refrigerating flow.
Condensing the stock flow to be liquefied through a main heat exchanger 3 (-81.07 ℃), decompressing the liquefied stock flow to the lowest pressure (2.5MPa, -99.2 ℃) of user gas supply through a throttle valve 9, generating flash steam in the process, and separating LNG and the flash steam through a gas-liquid separator 10; the refrigeration strand flows through a natural gas expander 5 to expand to generate low-temperature low-pressure (2.5MPa and-79.7 ℃) natural gas, the pressure of the natural gas meets the lowest pressure (2.5MPa) of gas supply of a user, and the natural gas enters a main heat exchanger 3 to exchange heat to obtain low-temperature low-pressure natural gas (2.5MPa and-62.56 ℃);
LNG is sent into an LNG pressure storage tank 11 for temporary storage, flash steam and low-pressure natural gas (2.5 MPa-62.56 ℃) subjected to heat exchange through a main heat exchanger 3 form confluence (2.5 MPa-76.88 ℃) in a mixer 6, and the mixed gas is finally sent into a precooling heat exchanger 1 to provide cold energy for the natural gas from a trunk line, and simultaneously, reheat the mixed gas is normal-temperature natural gas (2.5MPa, 30.5 ℃);
the nitrogen compressor 7 boosts the low-pressure nitrogen (3.74MPa and 30 ℃) to (8MPa and 128.1 ℃), the high-pressure nitrogen is cooled to 35 ℃ by the water cooler 8, enters the precooling heat exchanger 1 to precool to-45.4 ℃, and then is expanded by the nitrogen expander 4, and the low-pressure low-temperature nitrogen (3.78MPa and-84.92 ℃) is generated to provide extra cold for the main heat exchanger 3. The liquefaction rate of the case is 49.28 percent, and the specific energy consumption is 0.204 kWh.
The third working condition is as follows: when the upstream air supply of the main line is less than the downstream air consumption (Q)Upstream supply of gas＜QFor downstream useQi (Qi)) Stopping the incoming gas of the main line of each liquefaction process from entering the process, starting the pressurized LNG regasification method, starting the self-pressurizer in the LNG pressure storage tank 11 to drive the LNG in the tank to flow out through the liquid outlet 11.3, and flowing out the flash steam through the gas outlet 11.2; LNG and flash steam are converged in a second mixer 12 and flow into an air temperature gasifier 13, heat exchange is carried out between the LNG and air, the LNG and the flash steam are reheated to be higher than 0 ℃, the LNG and the air are gasified and then enter a downstream pipeline, the pressure of the reheated natural gas is matched with the lowest pressure requirement of a user, and the LNG and the flash steam supply gas to downstream urban gate stations. The tank capacity of the LNG pressure storage tank 11 needs to be designed and calculated according to the station scale and the peak shaving gas amount to meet the process requirements of liquefaction and peak shaving on different scales.
The utility model discloses a low energy consumption combined type natural gas liquefaction peak shaving system is when peak shaving load is high, and the natural gas strand flow that will treat the liquefaction of utilizing "cold volume" that the nitrogen expansion cycle produced carries out the condensation liquefaction, and the direct expansion technology of natural gas will regard as supplementary liquefaction means. When the peak load is low, the cold energy of the nitrogen expansion cycle is adjusted downwards, the direct expansion refrigeration of the natural gas is used as the main liquefaction process until the nitrogen expansion cycle is stopped, and the natural gas liquefaction process with zero energy consumption is adopted. LNG adopts the area to press and stores, adopts the self-pressurization mode in the storage tank, and LNG can directly supply gas to downstream city gate station after the air temperature vaporizer gasification.
In the above example, HYSYS software is adopted for simulation, and a global optimization algorithm is adopted for optimization of the operating parameters, the parameters are ideal optimal operating parameters, and the actual working conditions are affected by actual equipment and environment, so that a person skilled in the art can make corresponding adjustment to achieve the purpose of realizing the process flow. Details not described in this specification are within the skill of the art that are well known to those skilled in the art.

Claims (4)

1. The utility model provides a low energy consumption combined type natural gas liquefaction peak shaving system which characterized in that: the system comprises a precooling heat exchanger (1), a flow distributor (2), a main heat exchanger (3), a natural gas expander (5), a first mixer (6), a gas-liquid separator (10) and an LNG pressure storage tank (11);
the pre-cooling heat exchanger (1) is provided with a first air inlet (1.1), a first air outlet (1.2) of the pre-cooling heat exchanger (1) is connected with a gas inlet (2.1) of a flow distributor (2), a first gas outlet (2.2) of the flow distributor (2) is connected with a first inlet (3.1) of a main heat exchanger (3), a first outlet (3.2) of the main heat exchanger (3) is connected with an inlet (10.1) of a gas-liquid separator (10), a flash steam outlet (10.2) of the gas-liquid separator (10) is connected with a first feed inlet (6.1) of a first mixer (6), and an LNG outlet (10.3) of the gas-liquid separator (10) is connected with an LNG inlet (11.1) of an LNG pressure storage tank (11);
a second gas outlet (2.3) of the flow distributor (2) is connected with a second inlet (3.3) of the main heat exchanger (3) through a natural gas expander (5), and a second outlet (3.4) of the main heat exchanger (3) is connected with a second feeding hole (6.2) of the first mixer (6); and a discharge hole (6.3) of the first mixer (6) is connected with a second air inlet (1.5) of the precooling heat exchanger (1), and a second air outlet (1.6) is arranged on the precooling heat exchanger (1).
2. The low energy consumption composite natural gas liquefaction peak shaving system of claim 1, wherein: the device is characterized by also comprising a nitrogen expansion machine (4), a circulating nitrogen compressor (7), a water cooler (8) and a nitrogen buffer tank (14), wherein the nitrogen buffer tank (14) is provided with a nitrogen injection port (14.1), and a nitrogen outlet (14.2) of the nitrogen buffer tank (14) is connected with a nitrogen inlet (7.1) of the circulating nitrogen compressor (7);
the compressed nitrogen outlet (7.2) of the circulating nitrogen compressor (7) is connected with a third air inlet (1.3) of the precooling heat exchanger (1) through a water cooler (8), a third air outlet (1.4) of the precooling heat exchanger (1) is connected with a third inlet (3.5) of the main heat exchanger (3) through a nitrogen expansion machine (4), a third outlet (3.6) of the main heat exchanger (3) is connected with a fourth air inlet (1.7) of the precooling heat exchanger (1), and a fourth air outlet (1.8) of the precooling heat exchanger (1) is connected with an air inlet (14.3) of a nitrogen buffer tank (14).
3. The low energy consumption composite natural gas liquefaction peak shaving system of claim 2, wherein: the LNG high-pressure storage tank is characterized by further comprising a second mixer (12) and an air-temperature gasifier (13), wherein a gas outlet (11.2) of the LNG high-pressure storage tank (11) is connected with a first inlet (12.1) of the second mixer (12), a liquid outlet (11.3) of the LNG high-pressure storage tank (11) is connected with a second inlet (12.2) of the second mixer (12), a mixture outlet (12.3) of the second mixer (12) is connected with an inlet (13.1) of the air-temperature gasifier (13), and an outlet (13.2) of the air-temperature gasifier (13) is connected with a downstream pipeline.
4. The low energy consumption composite natural gas liquefaction peak shaving system of claim 1, 2 or 3, wherein: a throttle valve (9) is arranged on a pipeline between the first outlet (3.2) of the main heat exchanger (3) and the inlet (10.1) of the gas-liquid separator (10).
CN201920937600.9U 2019-06-20 2019-06-20 Low-energy-consumption combined type natural gas liquefaction peak regulation system Active CN210267883U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201920937600.9U CN210267883U (en) 2019-06-20 2019-06-20 Low-energy-consumption combined type natural gas liquefaction peak regulation system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201920937600.9U CN210267883U (en) 2019-06-20 2019-06-20 Low-energy-consumption combined type natural gas liquefaction peak regulation system

Publications (1)

Publication Number Publication Date
CN210267883U true CN210267883U (en) 2020-04-07

Family

ID=70043770

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201920937600.9U Active CN210267883U (en) 2019-06-20 2019-06-20 Low-energy-consumption combined type natural gas liquefaction peak regulation system

Country Status (1)

Country Link
CN (1) CN210267883U (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111607442A (en) * 2020-05-15 2020-09-01 重庆燃气集团股份有限公司 Comprehensive energy utilization system for natural gas storage and peak regulation and storage and peak regulation method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111607442A (en) * 2020-05-15 2020-09-01 重庆燃气集团股份有限公司 Comprehensive energy utilization system for natural gas storage and peak regulation and storage and peak regulation method

Similar Documents

Publication Publication Date Title
CN202371968U (en) Boil-off gas liquefaction recovery device for liquefied natural gas receiving station
CN202868298U (en) Gradient utilization system of LNG (Liquefied Natural Gas) cold energy
CN204063780U (en) A kind of pipeline gas differential pressure refrigeration liquefying device in conjunction with nitrogen swell refrigeration
CN101858683A (en) System for producing liquefied natural gas by utilizing liquid nitrogen cold energy
JP2016512595A (en) Natural gas liquefaction method and apparatus
CN102538390B (en) Novel natural gas liquefaction system and natural gas liquefaction method
CN103982774A (en) Process flow and device of multi-functional liquefied natural gas satellite station
CN210267883U (en) Low-energy-consumption combined type natural gas liquefaction peak regulation system
Bian et al. Analysis and efficiency enhancement for energy-saving re-liquefaction processes of boil-off gas without external refrigeration cycle on LNG carriers
CN201532077U (en) Natural gas liquefying device based on low temperature liquid refrigeration
CN103234118A (en) Liquefaction peak regulation method and device utilizing pressure energy of natural gas high-pressure pipe network
CN107560321B (en) BOG recovery and nitrogen liquefaction system and technological method
CN110779277B (en) Air separation energy-saving device for producing liquid nitrogen by utilizing LNG cold energy and mixed refrigeration working medium circulation
CN110185506B (en) Pressure energy comprehensive utilization system of natural gas pressure regulating station
CN203893579U (en) Complete equipment for comprehensively utilizing pressure energy of natural gas
CN204678800U (en) A kind of liquefying plant of mini gas
CN103175379A (en) Device for preparing liquefied natural gas with pipeline pressure energy and application method thereof
CN114087533B (en) Pressure regulating facility system and method for generating electricity and making ice by utilizing natural gas pressure energy
CN106322817B (en) LNG cold energy storage and synchronous cold energy supply operation system and method
CN205138074U (en) Utilize natural gas pipe network pressure can produce liquefied natural gas's device
CN114777411A (en) Hydrogen liquefying device with regeneration pipeline
CN110715504B (en) Residual pressure power generation liquefaction system of high-pressure natural gas
CN210089183U (en) Device for transferring LNG cold energy by using phase-change refrigerant
CN112414002A (en) Two-phase flow jet refrigeration system for BOG recovery and BOG recovery method
CN208703576U (en) The decrease temperature and pressure system of liquefied natural gas product in a kind of liquefied natural gas (LNG) plant

Legal Events

Date Code Title Description
GR01 Patent grant
GR01 Patent grant