WO2021063429A1 - Natural gas processing plant - Google Patents

Natural gas processing plant Download PDF

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Publication number
WO2021063429A1
WO2021063429A1 PCT/CZ2020/000045 CZ2020000045W WO2021063429A1 WO 2021063429 A1 WO2021063429 A1 WO 2021063429A1 CZ 2020000045 W CZ2020000045 W CZ 2020000045W WO 2021063429 A1 WO2021063429 A1 WO 2021063429A1
Authority
WO
WIPO (PCT)
Prior art keywords
natural gas
refrigerant
processing plant
pressure
block
Prior art date
Application number
PCT/CZ2020/000045
Other languages
French (fr)
Inventor
Thomas MERKER
Original Assignee
GasNet, s.r.o.
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 GasNet, s.r.o. filed Critical GasNet, s.r.o.
Priority to EP20797363.7A priority Critical patent/EP4038331A1/en
Publication of WO2021063429A1 publication Critical patent/WO2021063429A1/en

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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
    • 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
    • F25J1/0047—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
    • F25J1/0203—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
    • F25J1/0249—Controlling refrigerant inventory, i.e. composition or quantity
    • F25J1/025—Details related to the refrigerant production or treatment, e.g. make-up supply from feed gas itself
    • 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.
    • F25J1/0281—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc. characterised by the type of prime driver, e.g. hot gas expander
    • F25J1/0283—Gas turbine as the prime mechanical driver
    • 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.
    • F25J1/0285—Combination of different types of drivers mechanically coupled to the same refrigerant compressor, possibly split on multiple compressor casings
    • F25J1/0288—Combination of different types of drivers mechanically coupled to the same refrigerant compressor, possibly split on multiple compressor casings using work extraction by mechanical coupling of compression and expansion of the refrigerant, so-called companders
    • 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.
    • F25J1/0292—Refrigerant compression by cold or cryogenic suction of the refrigerant 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
    • F25J1/02—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
    • F25J1/0297—Removal of the heat of compression, e.g. within an inter- or afterstage-cooler against an ambient heat sink using an externally chilled fluid, e.g. chilled water
    • 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
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/06—Splitting of the feed stream, e.g. for treating or cooling in different ways
    • 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
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/42—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
    • 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
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/04—Compressor cooling arrangement, e.g. inter- or after-stage cooling or condensate removal
    • 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
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/20—Integrated compressor and process expander; Gear box arrangement; Multiple compressors on a common shaft
    • 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
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/90—Hot gas waste turbine of an indirect heated gas for power generation
    • 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
    • F25J2270/04—Internal refrigeration with work-producing gas expansion loop
    • 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
    • F25J2270/904—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration by liquid or gaseous cryogen in an open loop

Definitions

  • the invention relates to a plant for the treatment of natural gas, specifically to a plant for the treatment of natural gas comprising liquefaction.
  • the cooled gas stream is then comes into contact with a second cooling circuit in the heat exchanger consisting of at least one cooling stage, thereby lowering the temperature of the cooled gas stream to produce a methane-rich liquid product at a temperature above approximately -112 °C and a pressure sufficient to do so. to obtain a liquid product at or below the bubble boiling point.
  • a second cooling circuit in the heat exchanger consisting of at least one cooling stage, thereby lowering the temperature of the cooled gas stream to produce a methane-rich liquid product at a temperature above approximately -112 °C and a pressure sufficient to do so. to obtain a liquid product at or below the bubble boiling point.
  • the disadvantage of this method is the high internal energy consumption for the operation of the device that performs it.
  • the object of the invention is the design of a device for processing natural gas by liquefying it, which will have significantly lower operating costs.
  • a natural gas processing plant specifically a natural gas processing plant comprising at least one liquefaction block which comprises a natural gas intake, a liquefier, a circuit of refrigerant and an outlet for the liquified gas, which according to the invention, is characterised by that the liquefaction block is connected to at least one block for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas.
  • the advantage is that cold energy is recovered, which comes from reducing the pressure of the natural gas flow, especially in reduction stations in natural gas transmission or distribution networks or in the process of discharging gas from a natural gas storage tank, through valves or systems for gas expansion, or is otherwise obtained from already refrigerated natural gas, and its use in liquefying natural gas, which is drawn from the distribution network, for liquefied natural gas, while simultaneously reducing electricity consumption in the liquefaction process by using cold energy obtained by natural gas expansion.
  • the advantage is that cold energy which is easily exploited, causes problems in natural gas reduction stations during the reduction of the gas flow, such as the formation of solid methane-hydrates. Cold energy is used to save on the overheads of the natural gas liquefaction plant, as well as on the cost of preheating this flowing natural gas, which would be required to prevent the formation of solid methane-hydrates.
  • the block for reducing the pressure of the flowing natural gas comprises at least one expansion turbine which is connected by its at least one first outlet of the pressure-reduced natural gas to at least one heat exchanger which is part of the liquefaction block.
  • the liquefaction block further comprises a natural gas cleaning device, which is arranged on the natural gas intake before it enters the liquefier.
  • a natural gas cleaning device which is arranged on the natural gas intake before it enters the liquefier.
  • the at least one heat exchanger be located at the natural gas intake to the liquefier, most advantageously the heat exchanger being arranged between the natural gas purifier and the liquefier.
  • At least one heat exchanger is located on the refrigerant circuit, thus easily enabling the supply of cold energy from natural gas pressure reduction, and at the same time the reduced pressure natural gas is heated, which reduces complications caused by its low temperature during its distribution.
  • the block for reducing the pressure of the flowing natural gas further comprises a device for removing water from the natural gas, which is arranged before the expansion turbine on the natural gas intake.
  • the refrigerant circuit further comprises a refrigerant expansion turbine and at least one refrigerant compression device, which is a recycling compressor, and/or a secondary compressor, and/or a booster compressor.
  • a refrigerant expansion turbine and at least one refrigerant compression device, which is a recycling compressor, and/or a secondary compressor, and/or a booster compressor.
  • a liquifier is arranged on the refrigerant circuit, in the direction of movement of the refrigerant, which is connected to a recycling compressor which is connected to a heat exchanger which is connected to a secondary compressor which is connected to another heat exchanger which is connected to a booster compressor, which is connected to another heat exchanger, which is connected to a liquidiser.
  • the liquefier also comprises at least one exchanger arranged simultaneously on the refrigerant circuit in the direction of refrigerant movement, which is connected to a refrigerant expansion turbine arranged outside the liquefier which is connected to a liquefaction exchanger arranged within the liquefier.
  • the refrigerant expansion turbine is, by a shaft, connected to a booster compressor.
  • the advantage is a simple design solution that further reduces the energy consumption required for liquefaction.
  • the energy transfer from the refrigerant expansion turbine to the booster compressor can be solved such that the expansion turbine is connected to an electric energy generator, which is led to the booster compressor to its drive.
  • the liquefaction block further comprises a refrigerant refill line which is connected to the refrigerant circuit to make up for refrigerant losses in the refrigerant expansion turbine.
  • the refrigerant refill line is connected to the refrigerant circuit in at least one refrigerant expansion device.
  • the refrigerant expansion device is a secondary compressor and/or a recycling compressor to which a refrigerant refill line is connected.
  • the refrigerant refill line first passes through the liquidiser refrigerant exchanger.
  • the advantage is that the supplied refrigerant medium is in liquid form, while during its conversion into the gas phase, a release of cold energy results, which is advantageously exploited for further pre-cooling of the refrigerant medium before it enters the liquefaction process.
  • the expansion turbine arranged within the block for reducing the pressure of the flowing natural gas, is connected by a shaft to a secondary compressor arranged within the liquefaction block.
  • the energy transfer from the expansion turbine to the secondary compressor can again be solved by connecting the expansion turbine to an electric power generator, which is led to the secondary compressor to its drive.
  • the most advantageous refrigerant medium is nitrogen.
  • the natural gas processing plant further comprises at least one further independent block for reducing the pressure of the flowing natural gas.
  • the advantage is that it is possible to ensure a stable flow of supplied natural gas to at least one block for reducing the pressure of flowing natural gas, and that independently of seasonal changes in the size of the outgoing stream of pressure reduced natural gas, stable production of liquefied natural gas is ensured including periods when the total natural gas inflow is higher than the planned size of the natural gas flow through the pressure reducing block of the flowing natural gas and the liquefaction block, with the flow exceeding this planned size being directed to another independent pressure reducing block for the flowing natural gas.
  • the main advantage of the natural gas processing plant according to the invention is that it uses otherwise unused or even harmful cold energy which is generated during the natural gas pressure reduction process at natural gas pressure reduction stations usually located at the interface between high pressure and medium pressure or low pressure flow in the distribution or transmission networks of natural gas.
  • Another advantage is the possibility of producing liquefied natural gas even in areas remote from the liquefied natural gas terminals at competitive prices for natural gas, which is taken from conventional transmission or distribution networks.
  • Another potential advantage of the natural gas processing plant according to the invention is that it can be used as part of a gas regulation station to stabilise gas flow in periods of lower and higher consumption, when at the moment of lower gas consumption, for example in summer, excess natural gas it is liquefied and stored in a tank from which it is released at the moment of increased consumption, for example in winter, while the flow of gas entering the control station can still remain the same.
  • the natural gas processing plant according to the invention brings significant economic savings. Compared to the known solutions, there are significant savings in electricity during the operation of the nitrogen system. Less energy is required because part of the cooling energy is provided by the cooled gas flow from the block for reducing pressure of the flowing natural gas.
  • a known liquefaction plant with a capacity of 25 tones of liquefied natural gas, using nitrogen as a refrigerant medium, has a specific electricity consumption of at least 0.56 kWh per Nm 3 of liquefied natural gas, consuming at least 0.10 Nm 3 of nitrogen per Nm 3 of liquefied natural gas.
  • the natural gas processing plant according to the invention makes it possible to reduce the specific electricity consumption for liquefaction of natural gas by approximately 75%, with a slight increase in nitrogen consumption by approximately 0.03 Nm 3 of nitrogen per Nm 3 of liquefied natural gas. Furthermore, it is also very advantageous from the point of view of the distribution network operator that a considerable amount of energy can be saved for preheating, because the natural gas flow from the pressure reduction block for flowing natural gas has, after passing through the heat exchangers, a temperature higher than the required 4°C
  • Fig. 1 shows shows a circuit comprising a liquefaction block and a block for reducing the pressure of flowing natural gas
  • Fig. 2 shows a circuit comprising a liquefaction block, a block for reducing pressure of flowing natural gas and another independent block for reducing pressure of flowing natural gas.
  • the natural gas processing plant (Fig. 1) comprises a liquefaction block 1, which comprises a high-pressure natural gas intake 10, a liquefier 1J_, a refrigerant circuit 12 which is nitrogen, and a liquefied gas outlet 13.
  • the liquefaction block 1 is connected to a block 2 for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas.
  • the block 2 for reducing the pressure of flowing natural gas comprises an expansion turbine 4, which is connected by its first outlet 5 of pressure-reduced gas to four heat exchangers 6, 7, 8, 9, which are part of the liquefaction block 1
  • the expansion turbine 4 is further connected with its second outlet 34 connected to a reduction valve 35, which is further connected to a low-pressure natural gas outlet 24.
  • the block 2 for reducing the pressure of the flowing natural gas further comprises a device 15 for removing water from the natural gas, which is arranged before the expansion turbine 4 on the high-pressure natural gas intake 14.
  • the liquefaction block 1 further comprises a natural gas cleaning device 16, which is arranged on the high-pressure natural gas intake 10 before it enters the liquefier 11.
  • a heat exchanger 6 is arranged between the natural gas cleaning device 16 and the liquefier H on the high- pressure natural gas intake 10 to the liquefier H.
  • the refrigerant circuit 12 further comprises a refrigerant expansion turbine 17 and three refrigerant compression devices 25, which are a recycling compressor 18, a secondary compressor 19, and a booster compressor 20.
  • a liquefier H Arranged on the refrigerant circuit 12 in the direction of movement of the refrigerant, is arranged a liquefier H, which is connected to a recycling compressor 18,25, which is connected to a heat exchanger 7, which is connected to a secondary compressor 19,25, which is connected to another a heat exchanger 8, which is connected to a booster compressor 20,25, which is connected to another heat exchanger 9, which is connected to the liquifier TT
  • the liquifier H comprises an exchanger 30 arranged simultaneously on the refrigerant circuit 12 in the direction of movement of the refrigerant, which is connected to an expansion turbine 17 of the refrigerant arranged outside the liquifier H, which is connected to a liquefier exchanger 31 arranged within the liquifier H.
  • the refrigerant expansion turbine 17 is connected by a shaft 23 to a booster compressor 20. According to a variant not shown, the refrigerant expansion turbine 17 can be connected to an electric generator, which is connected by an electrical line to the booster compressor drive 20.
  • the expansion turbine 4 arranged in the block 2 for reducing the pressure of the flowing natural gas, is connected by a shaft 22 to a secondary compressor 19 arranged in the liquefaction block 1 According to a variant not shown, this expansion turbine 4 can be connected to an electric generator, which is connected by an electrical line to the drive of the secondary compressor 19.
  • the liquefaction block 1 further comprises a refrigerant refill line 21 which is connected to the refrigerant circuit 2 to replenish the refrigerant losses, with the refrigerant refill line 21 first passing through the refrigerant exchanger 30 of the liquefierll.
  • the refrigerant refill line 21 is, on the refrigerant circuit 12, connected in two refrigeration medium expansion devices 25, which are a secondary compressor 19 and a recycling compressor 18.
  • the natural gas processing plant operates in such a way that natural gas is led to the block 2 for reducing the pressure of the flowing natural gas through a high- pressure intake 14, with the cold energy from the pressure reduction process being subsequently used as part of the cold energy required for liquefying the natural gas.
  • water is removed from the flow of this natural gas in the device 15 for removing water from natural gas, thus preventing its contents in the cooled natural gas from freezing during or after expansion in the expansion turbine 4.
  • the device 15 for removing water from natural gas removes water in the flow of natural gas and reduces its content to 1 ppm.
  • the dry natural gas is led through the expansion turbine 4, with its pressure level decreasing from high pressure to medium pressure or low pressure- for example from pressure values of 80 to 40 bar to pressure values of 25 to 5 bar.
  • the temperature of the natural gas before the expansion turbine 4 fluctuates in the range of 4 o 20°C depending on the weather. Due to the adiabatic expansion, its temperature after expansion in the expansion turbine 4 reaches -40 to -25°C, while the higher the pressure ratio is at the gas intake on one side of the expansion turbine 4 and at the gas outlet behind the expansion turbine 4 on the other side, the lower are the temperatures reached.
  • the cooled natural gas flow enters the heat exchangers 6, 7, 8, 9 with a temperature of -40 to -25°C, while carrying the cold energy from the cooled natural gas flow from the block 2 for reducing the pressure of the flowing natural gas to the heat exchanger 6 for cooling the natural gas before entering the liquefier H, and in parallel via three heat exchangers 7,8,9 to the refrigerant medium, which is nitrogen, circulating in the refrigerant circuit 12 which is part of the liquefaction block 1, thereby pre-cooling the nitrogen before entering the liquefier H.
  • the refrigerant medium which is nitrogen
  • the refrigerant circuit 12 ensures repeated compression and expansion of the nitrogen, which reaches temperatures below -140°C in the gaseous state, at a pressure of 3 to 5 bar.
  • the natural gas stream to be liquefied first enters a natural gas purification device 16, in which CO2 and water, as well as other impurities in the natural gas stream, are removed. This prevents the freezing of C0 2 residues and water in the natural gas during the expansion and liquefaction process.
  • the natural gas flow is pre-cooled by passing the gas through a heat exchanger 6, with the temperature of the natural gas falling from 4 to 20°C to -30 to -15°C.
  • the natural gas stream enters the liquefier H, with the nitrogen gas in the liquefaction exchanger 34 transferring cold energy to it, whereby liquefied natural gas is formed, which exits the liquefier 1_1 at a temperature of -145 to -155 °C.
  • the devices arranged on the refrigerant circuit 12 operate in such a way that nitrogen gas circulates through the refrigerant circuit 12, with the nitrogen gas at -70°C to -60°C expanding in the refrigerant expansion turbine 17, reaching a temperature of -150°C to -140°C, with its outlet pressure from the expansion turbine 17 ranging from 3 bar to 5 bar. Nitrogen gas is then led in the liquefaction exchanger 31 to the reverse flow with the flow of natural gas.
  • the temperature of the nitrogen gas is increased by the liquefaction exchanger 31 from -150 to -140°C to -15 to -30°C, the temperature of the natural gas decreases from -15 to 30°C to -145 to -155°C, thus causing its liquefaction.
  • Nitrogen gas after transmitting the cold energy of the natural gas flow in the liquefaction exchanger 31, leaves the liquefier H at a temperature of -15 to -30°C and a pressure of 3 to 5 bar, and is sent to the suction of a recycling compressor 18 which pressurises the nitrogen gas to a pressure of 5 to 10 bar, at a temperature of +40 to +60°C. Nitrogen gas further enters the heat exchanger 7, in which its temperature drops from 40 to 60°C to -15 to -5°C. This ensures a lower nitrogen intake temperature to the secondary compressor 19, 25, which is further compressed to a pressure of 10 to 22 bar, at a temperature of +60 to +70°C.
  • Nitrogen gas further enters the heat exchanger 8, in which its temperature drops from 60 to 70°C to -15 to -5°C. This ensures a lower nitrogen intake temperature to the booster compressor 20, 25, which further compresses it to a pressure of 15 to 40 bar, at a temperature of +40 to + 50°C.
  • Nitrogen gas further enters the heat exchanger 9, in which its temperature drops from 40 to 50°C to -20 to -10°C. This ensures a lower nitrogen intake temperature to the liquefier 11
  • Nitrogen gas further enters the liquefier H, more precisely its exchanger 30, where due to the transfer of cold energy from the supplied liquid nitrogen and further the temperature of nitrogen gas circulating through the refrigerant circuit 12 it is reduced from values of -20 to -10°C to -70 to -60°C.
  • the liquefaction block further comprises an intake 33 of liquid refrigerant medium, which is liquid nitrogen, which enters at a flow rate of about 200 Nm 3 /h at a temperature of -170 to -175°C to the exchanger 30 of the liquefier U, in which the liquid nitrogen evaporates and from which it subsequently enters nitrogen gas with an average temperature of -20°C to the refill line 21, which leads it through the recycling compressor 18,25 and the secondary compressor 19.25, to the refrigerant circuit 12, to compensate for nitrogen leaks through the seals of the refrigerant expansion turbine 17, the recycle compressor 18, the secondary compressor 19, and the booster compressor 20.
  • liquid refrigerant medium which is liquid nitrogen
  • the liquefaction block further comprises an intake 33 of liquid refrigerant medium, which is liquid nitrogen, which enters at a flow rate of about 200 Nm 3 /h at a temperature of -170 to -175°C to the exchanger 30 of the liquefier U, in which the liquid nitrogen evaporates and from which it subsequently enters nitrogen
  • the temperature of the natural gas in the flow from the natural gas pressure reduction block 2 in the heat exchanger 6 increases from -40 to -25°C to 0 to 10°C, while the temperature of the gas flow entering the liquefier JM decreases from 4 to 20°C to -30 to -15°C.
  • the temperature of the natural gas in the flow from the natural gas pressure reduction block 2 increases in the heat exchanger 7 from -40 to -25 °C to 30 to 50°C, while the nitrogen temperature decreases from +40 to +60°C to -15 to -5°C.
  • the temperature of the natural gas in the flow the natural gas pressure reduction block 2 increases in the heat exchanger 8 from -40 to -25 °C to +40 to +55°C, while the nitrogen temperature decreases from +60 to +70 °C at -15 to -5°C.
  • the temperature of the natural gas in the low from the natural gas pressure reduction block 2 increases in the heat exchanger 9 from -40 to -25°C to 25 to 40°C, while the nitrogen temperature decreases from 40 to 50°C to -20 to -10°C.
  • the natural gas processing device (Fig. 2) comprises a liquefaction block 1, which comprises a high-pressure natural gas intake 10, a liquefier H, a refrigerant circuit 12, which is nitrogen, and a liquefied gas outlet 13.
  • the liquefaction block 1 is connected to a block 2 for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas.
  • the block 2 for reducing the pressure of flowing natural gas comprises an expansion turbine 4, which is connected by its first outlet 5 of pressure-reduced gas to four heat exchangers 6, 7, 8, 9, which are part of the liquefaction block 1
  • the expansion turbine 4 is further, to its second outlet 34. connected to a reduction valve 35, which is further connected to a low-pressure natural gas outlet 24.
  • the block 2 for reducing the pressure of the flowing natural gas further comprises a device 15 for removing water from the natural gas, which is arranged before the expansion turbine 4 on the high-pressure natural gas intake 14.
  • the liquefaction block further comprises a natural gas cleaning device 16, which is arranged on the high-pressure natural gas intake 10 before it enters the liquefier 11.
  • a heat exchanger 6 is arranged between the natural gas cleaning device 16 and the liquefier 1 on the high- pressure natural gas intake 10 to the liquefier H.
  • the refrigerant circuit 12 further comprises a refrigerant expansion turbine 17 and three refrigerant compression devices 25, which are a recycling compressor 18, a secondary compressor 19, and a booster compressor 20.
  • a liquefier H Arranged on the refrigerant circuit 12, in the direction of movement of the refrigerant, is arranged a liquefier H, which is connected to a recycling compressor 18, 25, which is connected to a heat exchanger 7, which is connected to a secondary compressor 19,25, which is connected to another a heat exchanger 8, which is connected to a booster compressor 20,25, which is connected to another heat exchanger 9, which is connected to the liquifier 11
  • the liquifier H comprises an exchanger 30 arranged simultaneously on the refrigerant circuit 12 in the direction of movement of the refrigerant, which is connected to an expansion turbine 17 of the refrigerant arranged outside the liquifier H, which is connected to a liquefier exchanger 31 arranged within the liquifier 11
  • the refrigerant expansion turbine 17 is connected by a shaft 23 to a booster compressor 20. According to a variant not shown, the refrigerant expansion turbine 17 can be connected to an electric generator, which is connected by an electrical line to the booster compressor drive 20.
  • the expansion turbine 4 arranged in the block 2 for reducing the pressure of the flowing natural gas, is connected by a shaft 22 to a secondary compressor 19 arranged in the liquefaction block 1 According to a variant not shown, this expansion turbine 4 can be connected to an electric generator, which is connected by an electrical line to the drive of the secondary compressor 19.
  • the liquefaction block 1 further comprises a refrigerant refill line 21 which is connected to the refrigerant circuit 12 to replenish the refrigerant losses, with the refrigerant refill line 21 first passing through the refrigerant exchanger 30 of the liquefier 11
  • the refrigerant refill line 21 is, on the refrigerant circuit 12 connected in two refrigeration medium expansion devices 25, which are a secondary compressor 19 and a recycling compressor 18.
  • the natural gas processing plant further comprises one further independent block 3 for reducing the pressure of the flowing natural gas.
  • the natural gas processing plant operates in the same way as the plant of Example 1, and in addition operates in the independent block 3 to reduce the pressure of the flowing natural gas so that while a stable gas flow is passed through high pressure intakes 10,14 to the liquefaction block 1 and to the reduction block 2 for pressure of the flowing natural gas, the remaining gas volume flow exceeding the proposed flow through the liquefaction block 1 is led by a high pressure natural gas intake 29 through a preheater 27 to an expansion turbine 26, which is connected to a generator 28. If the gas flow exceedance is relatively small, it is utilised to perform the gas pressure reduction instead of the expansion turbine’s 26 throttle valve 32.
  • the throttle valve 32 also serves as a backup solution for bypassing the gas around the expansion turbine 26 in case of emergency, expansion system repairs, or other situations where operation is not possible.
  • the preheater 27 is installed to prevent undesired freezing of water and condensation of heavy hydrocarbons in the expanded natural gas.
  • the natural gas processing plant according to the invention can in particular be used for the production of liquefied natural gas and for the production of natural gas with reduced pressure.

Abstract

A natural gas processing plant, in particular a natural gas processing plant comprising at least one liquefaction block (1) comprising a natural gas intake (10), a liquefier (11), a refrigerant circuit (12) and a liquefied gas outlet (13), where the liquefaction block (1) is connected to at least one block (2) for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas.

Description

Natural gas processing plant
Technical Field
The invention relates to a plant for the treatment of natural gas, specifically to a plant for the treatment of natural gas comprising liquefaction.
State of the Art
A number of methods and constructive solutions for gas liquefaction plants are known from current technology. Natural gas liquefaction plants are also known.
From patent document CZ PV 1998-536 a process is known for liquefying hydrocarbon-rich gas which is carried out by means of a cryogenerator in such a way that by means of an absorber, the gas is first purified from the liquefying interfering components, in particular water vapour and carbon dioxide. The purified gas is cooled, with the cooling being realised by expansion in an expansion turbine. The gas is further liquefied by means of a cryogenerator and finally the gas is led to a storage tank. The device for carrying out this method consists of an absorber, a cooling device or a separating unit, a cryogenerator, a storage tank, a motor which drives the cryogenerator and an electric generator. The disadvantage of this method and device is low productivity and especially high energy consumption to its drive.
From a further patent document CZ PV 1999-4556 is known a process for liquefying a methane-rich gas stream with a pressure of approximately 3103 kPa, where the stream of gas further expands to a lower pressure, from which form a gas phase and a liquid product at a temperature below -112°C and sufficient pressure to keep the liquid product at the bubble boiling point or below it. The gas phase and the liquid product are then separated in a suitable phase separator and the liquid product is then fed into a holding device for storage at a temperature below -112°C. The disadvantage of this method is the high energy consumption for the operation of the equipment that performs it.
From patent document CZ PV 1999-4557 is known a process for liquefying compressed methane-rich natural gas with a heat exchanger cooled by a cascade cooling system to form a liquid methane-rich product at a temperature of approximately 112°C. During the process, a stream of compressed gas comes into contact in the heat exchanger with a first cooling circuit consisting of at least one cooling stage, whereby the gas stream is cooled by a first portion of the first refrigerant to form a cooled gas stream. The cooled gas stream is then comes into contact with a second cooling circuit in the heat exchanger consisting of at least one cooling stage, thereby lowering the temperature of the cooled gas stream to produce a methane-rich liquid product at a temperature above approximately -112 °C and a pressure sufficient to do so. to obtain a liquid product at or below the bubble boiling point. As with previous design solutions, the disadvantage of this method is the high internal energy consumption for the operation of the device that performs it.
From the above current technology a number of disadvantages are known, while it the most significant disadvantage it seems is that the known devices, and their methods of operation, have a high energy consumption for their operation.
The object of the invention is the design of a device for processing natural gas by liquefying it, which will have significantly lower operating costs.
Principle of the Invention
The above-mentioned disadvantages are largely eliminated and the objects of the invention are fulfilled by a natural gas processing plant, specifically a natural gas processing plant comprising at least one liquefaction block which comprises a natural gas intake, a liquefier, a circuit of refrigerant and an outlet for the liquified gas, which according to the invention, is characterised by that the liquefaction block is connected to at least one block for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas. The advantage is that cold energy is recovered, which comes from reducing the pressure of the natural gas flow, especially in reduction stations in natural gas transmission or distribution networks or in the process of discharging gas from a natural gas storage tank, through valves or systems for gas expansion, or is otherwise obtained from already refrigerated natural gas, and its use in liquefying natural gas, which is drawn from the distribution network, for liquefied natural gas, while simultaneously reducing electricity consumption in the liquefaction process by using cold energy obtained by natural gas expansion. The advantage is that cold energy which is easily exploited, causes problems in natural gas reduction stations during the reduction of the gas flow, such as the formation of solid methane-hydrates. Cold energy is used to save on the overheads of the natural gas liquefaction plant, as well as on the cost of preheating this flowing natural gas, which would be required to prevent the formation of solid methane-hydrates.
In an advantageous design, the block for reducing the pressure of the flowing natural gas comprises at least one expansion turbine which is connected by its at least one first outlet of the pressure-reduced natural gas to at least one heat exchanger which is part of the liquefaction block. The advantage of this design solution is that it is the relatively simplest and cheapest connection of the block for reducing the pressure of flowing natural gas to the liquefaction block.
It is also advantageous if the liquefaction block further comprises a natural gas cleaning device, which is arranged on the natural gas intake before it enters the liquefier. The advantage is that at the outlet of the treatment plant, the natural gas contains only what can be liquefied, while the treatment plant removes from the natural gas all components that could cause problems during liquefaction and which would at the same time reduce the quality of the liquefied natural gas.
It is to further advantage that the at least one heat exchanger be located at the natural gas intake to the liquefier, most advantageously the heat exchanger being arranged between the natural gas purifier and the liquefier. The advantage is that the natural gas entering the liquefier is pre-cooled and thus the liquefaction process is simplified and streamlined.
Furthermore, it is also to great advantage if at least one heat exchanger is located on the refrigerant circuit, thus easily enabling the supply of cold energy from natural gas pressure reduction, and at the same time the reduced pressure natural gas is heated, which reduces complications caused by its low temperature during its distribution.
To advantage, the block for reducing the pressure of the flowing natural gas further comprises a device for removing water from the natural gas, which is arranged before the expansion turbine on the natural gas intake. The advantage is that water is removed, which would otherwise cause problems in reducing the pressure of the natural gas, more precisely it could cause a restriction of the flow due to its freezing onto the walls.
It is very advantageous if the refrigerant circuit further comprises a refrigerant expansion turbine and at least one refrigerant compression device, which is a recycling compressor, and/or a secondary compressor, and/or a booster compressor. The advantage is that these devices ensure the cooling of the refrigerant medium so that the liquefaction takes place quickly, effectively and without complications.
In an optimal design, a liquifier is arranged on the refrigerant circuit, in the direction of movement of the refrigerant, which is connected to a recycling compressor which is connected to a heat exchanger which is connected to a secondary compressor which is connected to another heat exchanger which is connected to a booster compressor, which is connected to another heat exchanger, which is connected to a liquidiser. The advantage being that it is possible, before the refrigerant re-enters the liquefier, to prepare the most advantageous temperature of the refrigerant medium for the liquefaction process.
In an advantageous design, the liquefier also comprises at least one exchanger arranged simultaneously on the refrigerant circuit in the direction of refrigerant movement, which is connected to a refrigerant expansion turbine arranged outside the liquefier which is connected to a liquefaction exchanger arranged within the liquefier.
Furthermore, it is to advantage if the refrigerant expansion turbine is, by a shaft, connected to a booster compressor. The advantage is a simple design solution that further reduces the energy consumption required for liquefaction. Alternatively, the energy transfer from the refrigerant expansion turbine to the booster compressor can be solved such that the expansion turbine is connected to an electric energy generator, which is led to the booster compressor to its drive.
It is also advantageous if the liquefaction block further comprises a refrigerant refill line which is connected to the refrigerant circuit to make up for refrigerant losses in the refrigerant expansion turbine.
It is to advantage if the refrigerant refill line is connected to the refrigerant circuit in at least one refrigerant expansion device. In the most advantageous embodiment, the refrigerant expansion device is a secondary compressor and/or a recycling compressor to which a refrigerant refill line is connected. The advantage is a relatively simple design ensuring trouble-free operation.
It is also advantageous if the refrigerant refill line first passes through the liquidiser refrigerant exchanger. The advantage is that the supplied refrigerant medium is in liquid form, while during its conversion into the gas phase, a release of cold energy results, which is advantageously exploited for further pre-cooling of the refrigerant medium before it enters the liquefaction process.
From the point of view of another significant cost saving, it is advantageous if the expansion turbine, arranged within the block for reducing the pressure of the flowing natural gas, is connected by a shaft to a secondary compressor arranged within the liquefaction block. Alternatively, the energy transfer from the expansion turbine to the secondary compressor can again be solved by connecting the expansion turbine to an electric power generator, which is led to the secondary compressor to its drive.
From a technical point of view, the most advantageous refrigerant medium is nitrogen.
It is furthermore to great advantage if the natural gas processing plant further comprises at least one further independent block for reducing the pressure of the flowing natural gas. The advantage is that it is possible to ensure a stable flow of supplied natural gas to at least one block for reducing the pressure of flowing natural gas, and that independently of seasonal changes in the size of the outgoing stream of pressure reduced natural gas, stable production of liquefied natural gas is ensured including periods when the total natural gas inflow is higher than the planned size of the natural gas flow through the pressure reducing block of the flowing natural gas and the liquefaction block, with the flow exceeding this planned size being directed to another independent pressure reducing block for the flowing natural gas.
The main advantage of the natural gas processing plant according to the invention is that it uses otherwise unused or even harmful cold energy which is generated during the natural gas pressure reduction process at natural gas pressure reduction stations usually located at the interface between high pressure and medium pressure or low pressure flow in the distribution or transmission networks of natural gas.
Another advantage is the possibility of producing liquefied natural gas even in areas remote from the liquefied natural gas terminals at competitive prices for natural gas, which is taken from conventional transmission or distribution networks. Another potential advantage of the natural gas processing plant according to the invention is that it can be used as part of a gas regulation station to stabilise gas flow in periods of lower and higher consumption, when at the moment of lower gas consumption, for example in summer, excess natural gas it is liquefied and stored in a tank from which it is released at the moment of increased consumption, for example in winter, while the flow of gas entering the control station can still remain the same.
The natural gas processing plant according to the invention brings significant economic savings. Compared to the known solutions, there are significant savings in electricity during the operation of the nitrogen system. Less energy is required because part of the cooling energy is provided by the cooled gas flow from the block for reducing pressure of the flowing natural gas. For comparison, a known liquefaction plant, with a capacity of 25 tones of liquefied natural gas, using nitrogen as a refrigerant medium, has a specific electricity consumption of at least 0.56 kWh per Nm3 of liquefied natural gas, consuming at least 0.10 Nm3 of nitrogen per Nm3 of liquefied natural gas. The natural gas processing plant according to the invention makes it possible to reduce the specific electricity consumption for liquefaction of natural gas by approximately 75%, with a slight increase in nitrogen consumption by approximately 0.03 Nm3 of nitrogen per Nm3 of liquefied natural gas. Furthermore, it is also very advantageous from the point of view of the distribution network operator that a considerable amount of energy can be saved for preheating, because the natural gas flow from the pressure reduction block for flowing natural gas has, after passing through the heat exchangers, a temperature higher than the required 4°C
Overview of the Figures
The invention will be further elucidated using drawings, in which Fig. 1 shows shows a circuit comprising a liquefaction block and a block for reducing the pressure of flowing natural gas and Fig. 2 shows a circuit comprising a liquefaction block, a block for reducing pressure of flowing natural gas and another independent block for reducing pressure of flowing natural gas.
Examples of the Performance of the Invention
Example 1
The natural gas processing plant (Fig. 1) comprises a liquefaction block 1, which comprises a high-pressure natural gas intake 10, a liquefier 1J_, a refrigerant circuit 12 which is nitrogen, and a liquefied gas outlet 13. The liquefaction block 1 is connected to a block 2 for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas.
The block 2 for reducing the pressure of flowing natural gas comprises an expansion turbine 4, which is connected by its first outlet 5 of pressure-reduced gas to four heat exchangers 6, 7, 8, 9, which are part of the liquefaction block 1 The expansion turbine 4 is further connected with its second outlet 34 connected to a reduction valve 35, which is further connected to a low-pressure natural gas outlet 24.
The block 2 for reducing the pressure of the flowing natural gas further comprises a device 15 for removing water from the natural gas, which is arranged before the expansion turbine 4 on the high-pressure natural gas intake 14.
The liquefaction block 1 further comprises a natural gas cleaning device 16, which is arranged on the high-pressure natural gas intake 10 before it enters the liquefier 11.
Between the natural gas cleaning device 16 and the liquefier H on the high- pressure natural gas intake 10 to the liquefier H, a heat exchanger 6 is arranged.
On the refrigerant circuit 12 three heat exchangers 7,8,9 are arranged.
The refrigerant circuit 12 further comprises a refrigerant expansion turbine 17 and three refrigerant compression devices 25, which are a recycling compressor 18, a secondary compressor 19, and a booster compressor 20.
Arranged on the refrigerant circuit 12 in the direction of movement of the refrigerant, is arranged a liquefier H, which is connected to a recycling compressor 18,25, which is connected to a heat exchanger 7, which is connected to a secondary compressor 19,25, which is connected to another a heat exchanger 8, which is connected to a booster compressor 20,25, which is connected to another heat exchanger 9, which is connected to the liquifier TT
The liquifier H comprises an exchanger 30 arranged simultaneously on the refrigerant circuit 12 in the direction of movement of the refrigerant, which is connected to an expansion turbine 17 of the refrigerant arranged outside the liquifier H, which is connected to a liquefier exchanger 31 arranged within the liquifier H.
The refrigerant expansion turbine 17 is connected by a shaft 23 to a booster compressor 20. According to a variant not shown, the refrigerant expansion turbine 17 can be connected to an electric generator, which is connected by an electrical line to the booster compressor drive 20.
The expansion turbine 4, arranged in the block 2 for reducing the pressure of the flowing natural gas, is connected by a shaft 22 to a secondary compressor 19 arranged in the liquefaction block 1 According to a variant not shown, this expansion turbine 4 can be connected to an electric generator, which is connected by an electrical line to the drive of the secondary compressor 19.
The liquefaction block 1 further comprises a refrigerant refill line 21 which is connected to the refrigerant circuit 2 to replenish the refrigerant losses, with the refrigerant refill line 21 first passing through the refrigerant exchanger 30 of the liquefierll. The refrigerant refill line 21 is, on the refrigerant circuit 12, connected in two refrigeration medium expansion devices 25, which are a secondary compressor 19 and a recycling compressor 18.
The natural gas processing plant operates in such a way that natural gas is led to the block 2 for reducing the pressure of the flowing natural gas through a high- pressure intake 14, with the cold energy from the pressure reduction process being subsequently used as part of the cold energy required for liquefying the natural gas.
Firstly, water is removed from the flow of this natural gas in the device 15 for removing water from natural gas, thus preventing its contents in the cooled natural gas from freezing during or after expansion in the expansion turbine 4. The device 15 for removing water from natural gas removes water in the flow of natural gas and reduces its content to 1 ppm.
The dry natural gas is led through the expansion turbine 4, with its pressure level decreasing from high pressure to medium pressure or low pressure- for example from pressure values of 80 to 40 bar to pressure values of 25 to 5 bar.
The temperature of the natural gas before the expansion turbine 4 fluctuates in the range of 4 o 20°C depending on the weather. Due to the adiabatic expansion, its temperature after expansion in the expansion turbine 4 reaches -40 to -25°C, while the higher the pressure ratio is at the gas intake on one side of the expansion turbine 4 and at the gas outlet behind the expansion turbine 4 on the other side, the lower are the temperatures reached.
Thus, the cooled natural gas flow enters the heat exchangers 6, 7, 8, 9 with a temperature of -40 to -25°C, while carrying the cold energy from the cooled natural gas flow from the block 2 for reducing the pressure of the flowing natural gas to the heat exchanger 6 for cooling the natural gas before entering the liquefier H, and in parallel via three heat exchangers 7,8,9 to the refrigerant medium, which is nitrogen, circulating in the refrigerant circuit 12 which is part of the liquefaction block 1, thereby pre-cooling the nitrogen before entering the liquefier H.
Another part of the natural gas processing plant, which is the liquefaction block 1, comprises a circuit 12 of a refrigerant medium, which is nitrogen. The refrigerant circuit 12 ensures repeated compression and expansion of the nitrogen, which reaches temperatures below -140°C in the gaseous state, at a pressure of 3 to 5 bar.
The natural gas stream to be liquefied first enters a natural gas purification device 16, in which CO2 and water, as well as other impurities in the natural gas stream, are removed. This prevents the freezing of C02 residues and water in the natural gas during the expansion and liquefaction process.
After the purification device 16, the natural gas flow is pre-cooled by passing the gas through a heat exchanger 6, with the temperature of the natural gas falling from 4 to 20°C to -30 to -15°C.
Subsequently, the natural gas stream enters the liquefier H, with the nitrogen gas in the liquefaction exchanger 34 transferring cold energy to it, whereby liquefied natural gas is formed, which exits the liquefier 1_1 at a temperature of -145 to -155 °C.
The devices arranged on the refrigerant circuit 12 operate in such a way that nitrogen gas circulates through the refrigerant circuit 12, with the nitrogen gas at -70°C to -60°C expanding in the refrigerant expansion turbine 17, reaching a temperature of -150°C to -140°C, with its outlet pressure from the expansion turbine 17 ranging from 3 bar to 5 bar. Nitrogen gas is then led in the liquefaction exchanger 31 to the reverse flow with the flow of natural gas.
While the temperature of the nitrogen gas is increased by the liquefaction exchanger 31 from -150 to -140°C to -15 to -30°C, the temperature of the natural gas decreases from -15 to 30°C to -145 to -155°C, thus causing its liquefaction.
Nitrogen gas, after transmitting the cold energy of the natural gas flow in the liquefaction exchanger 31, leaves the liquefier H at a temperature of -15 to -30°C and a pressure of 3 to 5 bar, and is sent to the suction of a recycling compressor 18 which pressurises the nitrogen gas to a pressure of 5 to 10 bar, at a temperature of +40 to +60°C. Nitrogen gas further enters the heat exchanger 7, in which its temperature drops from 40 to 60°C to -15 to -5°C. This ensures a lower nitrogen intake temperature to the secondary compressor 19, 25, which is further compressed to a pressure of 10 to 22 bar, at a temperature of +60 to +70°C.
Nitrogen gas further enters the heat exchanger 8, in which its temperature drops from 60 to 70°C to -15 to -5°C. This ensures a lower nitrogen intake temperature to the booster compressor 20, 25, which further compresses it to a pressure of 15 to 40 bar, at a temperature of +40 to + 50°C.
Nitrogen gas further enters the heat exchanger 9, in which its temperature drops from 40 to 50°C to -20 to -10°C. This ensures a lower nitrogen intake temperature to the liquefier 11
Nitrogen gas further enters the liquefier H, more precisely its exchanger 30, where due to the transfer of cold energy from the supplied liquid nitrogen and further the temperature of nitrogen gas circulating through the refrigerant circuit 12 it is reduced from values of -20 to -10°C to -70 to -60°C.
Subsequently, the circulation of nitrogen gas through the refrigerant circuit 12 is closed by its re-entry into the refrigerant expansion turbine 17.
The liquefaction block further comprises an intake 33 of liquid refrigerant medium, which is liquid nitrogen, which enters at a flow rate of about 200 Nm3/h at a temperature of -170 to -175°C to the exchanger 30 of the liquefier U, in which the liquid nitrogen evaporates and from which it subsequently enters nitrogen gas with an average temperature of -20°C to the refill line 21, which leads it through the recycling compressor 18,25 and the secondary compressor 19.25, to the refrigerant circuit 12, to compensate for nitrogen leaks through the seals of the refrigerant expansion turbine 17, the recycle compressor 18, the secondary compressor 19, and the booster compressor 20.
As for the supply of the flow of cold natural gas from the block 2 for reducing the pressure of the flowing natural gas to the heat exchangers 6, 7, 8, 9, it is supplied to them at a temperature of -40 to -25°C and at a pressure of 6 to 26 bar.
The temperature of the natural gas in the flow from the natural gas pressure reduction block 2 in the heat exchanger 6 increases from -40 to -25°C to 0 to 10°C, while the temperature of the gas flow entering the liquefier JM decreases from 4 to 20°C to -30 to -15°C. The temperature of the natural gas in the flow from the natural gas pressure reduction block 2 increases in the heat exchanger 7 from -40 to -25 °C to 30 to 50°C, while the nitrogen temperature decreases from +40 to +60°C to -15 to -5°C.
The temperature of the natural gas in the flow the natural gas pressure reduction block 2 increases in the heat exchanger 8 from -40 to -25 °C to +40 to +55°C, while the nitrogen temperature decreases from +60 to +70 °C at -15 to -5°C.
The temperature of the natural gas in the low from the natural gas pressure reduction block 2 increases in the heat exchanger 9 from -40 to -25°C to 25 to 40°C, while the nitrogen temperature decreases from 40 to 50°C to -20 to -10°C.
Example 2
The natural gas processing device (Fig. 2) comprises a liquefaction block 1, which comprises a high-pressure natural gas intake 10, a liquefier H, a refrigerant circuit 12, which is nitrogen, and a liquefied gas outlet 13. The liquefaction block 1 is connected to a block 2 for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas.
The block 2 for reducing the pressure of flowing natural gas comprises an expansion turbine 4, which is connected by its first outlet 5 of pressure-reduced gas to four heat exchangers 6, 7, 8, 9, which are part of the liquefaction block 1 The expansion turbine 4 is further, to its second outlet 34. connected to a reduction valve 35, which is further connected to a low-pressure natural gas outlet 24.
The block 2 for reducing the pressure of the flowing natural gas further comprises a device 15 for removing water from the natural gas, which is arranged before the expansion turbine 4 on the high-pressure natural gas intake 14.
The liquefaction block further comprises a natural gas cleaning device 16, which is arranged on the high-pressure natural gas intake 10 before it enters the liquefier 11.
Between the natural gas cleaning device 16 and the liquefier 1 on the high- pressure natural gas intake 10 to the liquefier H, a heat exchanger 6 is arranged.
On the refrigerant circuit 12 three heat exchangers 7,8,9 are arranged.
The refrigerant circuit 12 further comprises a refrigerant expansion turbine 17 and three refrigerant compression devices 25, which are a recycling compressor 18, a secondary compressor 19, and a booster compressor 20. Arranged on the refrigerant circuit 12, in the direction of movement of the refrigerant, is arranged a liquefier H, which is connected to a recycling compressor 18, 25, which is connected to a heat exchanger 7, which is connected to a secondary compressor 19,25, which is connected to another a heat exchanger 8, which is connected to a booster compressor 20,25, which is connected to another heat exchanger 9, which is connected to the liquifier 11
The liquifier H comprises an exchanger 30 arranged simultaneously on the refrigerant circuit 12 in the direction of movement of the refrigerant, which is connected to an expansion turbine 17 of the refrigerant arranged outside the liquifier H, which is connected to a liquefier exchanger 31 arranged within the liquifier 11
The refrigerant expansion turbine 17 is connected by a shaft 23 to a booster compressor 20. According to a variant not shown, the refrigerant expansion turbine 17 can be connected to an electric generator, which is connected by an electrical line to the booster compressor drive 20.
The expansion turbine 4, arranged in the block 2 for reducing the pressure of the flowing natural gas, is connected by a shaft 22 to a secondary compressor 19 arranged in the liquefaction block 1 According to a variant not shown, this expansion turbine 4 can be connected to an electric generator, which is connected by an electrical line to the drive of the secondary compressor 19.
The liquefaction block 1 further comprises a refrigerant refill line 21 which is connected to the refrigerant circuit 12 to replenish the refrigerant losses, with the refrigerant refill line 21 first passing through the refrigerant exchanger 30 of the liquefier 11 The refrigerant refill line 21 is, on the refrigerant circuit 12 connected in two refrigeration medium expansion devices 25, which are a secondary compressor 19 and a recycling compressor 18.
The natural gas processing plant further comprises one further independent block 3 for reducing the pressure of the flowing natural gas.
The natural gas processing plant operates in the same way as the plant of Example 1, and in addition operates in the independent block 3 to reduce the pressure of the flowing natural gas so that while a stable gas flow is passed through high pressure intakes 10,14 to the liquefaction block 1 and to the reduction block 2 for pressure of the flowing natural gas, the remaining gas volume flow exceeding the proposed flow through the liquefaction block 1 is led by a high pressure natural gas intake 29 through a preheater 27 to an expansion turbine 26, which is connected to a generator 28. If the gas flow exceedance is relatively small, it is utilised to perform the gas pressure reduction instead of the expansion turbine’s 26 throttle valve 32. The throttle valve 32 also serves as a backup solution for bypassing the gas around the expansion turbine 26 in case of emergency, expansion system repairs, or other situations where operation is not possible.
The preheater 27 is installed to prevent undesired freezing of water and condensation of heavy hydrocarbons in the expanded natural gas.
Industrial Application
The natural gas processing plant according to the invention can in particular be used for the production of liquefied natural gas and for the production of natural gas with reduced pressure.
List of Reference Marks
1 liquefaction block
2 block for reducing the pressure of flowing natural gas
3 independent block for reducing the pressure of flowing natural gas
4 expansion turbine
5 first pressure-reduced gas outlet
6 heat exchanger I
7 heat exchanger II
8 heat exchanger III
9 heat exchanger IV
10 natural gas intake I
11 liquefier
12 refrigerant circuit
13 liquefied gas outlet
14 natural gas intake II
15 device for removing water from natural gas
16 natural gas cleaning device
17 refrigerant expansion turbine
18 recycling compressor
19 secondary compressor
20 booster compressor
21 refill line
22 shaft I
23 shaft II
24 low pressure natural gas outlet
25 refrigerant compression equipment
26 first expansion turbine
27 preheater
28 electric generator
29 natural gas intake III
30 exchanger
31 liquefaction exchanger throttle valve I liquid nitrogen intake second output throttle valve II

Claims

Patent Claims
1. A natural gas processing plant, in particular a natural gas processing plant comprising at least one liquefaction block (1), which comprises a natural gas intake (10), a liquefier (11), a refrigerant circuit (12) and a liquefied gas outlet (13), characterised in that the liquefaction block (1) is connected to at least one block (2) for reducing the pressure of the flowing natural gas to obtain cold energy from the pressure-reduced natural gas.
2. The natural gas processing plant according to claim 1, characterised in that the block (2) for reducing the pressure of the flowing natural gas comprises at least one expansion turbine (4) which is, by at least one first pressure-reduced gas outlet (5), connected to at least one heat exchanger (6, 7, 8, 9) which is part of the liquefaction block (1 ).
3. The natural gas processing plant according to any one of the preceding claims, characterised in that the liquefaction block (1) further comprises a natural gas cleaning device (16) which is arranged on the intake (10) of the natural gas before its entry into the liquefier (11).
4. The natural gas processing plant according to either one of claims 2 and 3, characterised in that at least one heat exchanger (6) is arranged on the natural gas intake (10) to the liquefier (11).
5. The natural gas processing plant according to one of claims 2 to 4, characterised in that the heat exchanger (6) is arranged between the natural gas cleaning device (16) and the liquefier (11).
6. The natural gas processing plant according to any one of claims 2 to 5, characterised in that at least one heat exchanger (7, 8, 9) is arranged on the circuit (12) of refrigerant medium.
7. The natural gas processing plant according to one of the preceding claims, characterised in that the block (2) for reducing the pressure of the flowing natural gas further comprises a device (15) for removing water from the natural gas, which is arranged before of the expansion turbine (4) on the natural gas intake (14).
8. The natural gas processing plant according to one of the preceding claims, characterised in that the refrigerant circuit (12) further comprises an expansion turbine (17) of the refrigerant and at least one device (25) for compressing the refrigerant, which is a recycling compressor (18), and/or a secondary compressor (19), and/or a booster compressor (20).
9. The natural gas processing plant according to any one of the preceding claims, characterised in that on the refrigerant medium circuit (12) in the direction of movement of the refrigerant medium a liquefier (11) is arranged which is connected to a recycling compressor (18,25) which is connected to a heat exchanger (7) which is connected to a secondary compressor (19,25) which is connected to another heat exchanger (8) which is connected to a booster compressor (20,25) which is connected to another heat exchanger (9) which is connected to the liquifier (11).
10. The natural gas processing plant according to claim 9, characterised in that the liquefier (11) comprises at least one exchanger (30) arranged simultaneously on the refrigerant circuit (12) in a direction of movement of the refrigerant, which is connected to an expansion turbine (17) for the refrigerant arranged outside the liquifier (11), which is connected to a liquefaction exchanger (31) arranged within the liquifier (11).
11. The natural gas processing plant according to claim 10, characterised in that the expansion turbine (17) of the refrigerant is connected by a shaft (23) to a booster compressor (20).
12. The natural gas processing plant according to one of the preceding claims, characterised in that the liquefaction block (1) further comprises a refill line (21) for the refrigerant medium which is connected to the circuit (12) of refrigerant to replenish refrigerant losses.
13. The natural gas processing plant according to claim 12, characterised in that the refrigerant refill line (21) is connected to the refrigerant circuit (12) in at least one device (25) for refrigerant expansion.
14. The natural gas processing plant according to either one of claims 12 and 13, characterised in that the refrigerant refill line (21) first passes through the exchanger (30) of the liquefier (11).
15. The natural gas processing plant according to any one of claims 2 to 14, characterised in that the expansion turbine (4) arranged in the block (2) for reducing the pressure of the flowing natural gas is, by a shaft (22), connected to a secondary compressor (19) arranged within the liquefaction block (1).
16. The natural gas processing plant according to one of the preceding claims, characterised in that it further comprises at least one further independent block (3) for reducing the pressure of the flowing natural gas.
17. The natural gas processing plant according to one of the preceding claims, characterised in that the refrigerant medium is nitrogen.
PCT/CZ2020/000045 2019-10-04 2020-10-02 Natural gas processing plant WO2021063429A1 (en)

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