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
  • F25J1/0032—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
  • F25J1/0032—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"
  • F25J1/0042—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 liquid 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
  • F25J1/0047—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
  • F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
  • F25J1/008—Hydrocarbons
  • F25J1/0092—Mixtures of hydrocarbons comprising possibly also minor amounts of 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
  • F25J1/0202—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 in a quasi-closed internal refrigeration 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
  • 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
  • F25J1/0211—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a multi-component refrigerant [MCR] fluid in a closed vapor compression cycle
  • F25J1/0212—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a multi-component refrigerant [MCR] fluid in a closed vapor compression cycle as a single flow MCR cycle
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
  • F25J1/0225—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using other external refrigeration means not provided before, e.g. heat driven absorption chillers
• • 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
  • F25J1/0254—Operation; Control and regulation; Instrumentation controlling particular process parameter, e.g. pressure, temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
  • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
  • F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
  • F25J1/0269—Arrangement of liquefaction units or equipments fulfilling the same process step, e.g. multiple "trains" concept
  • F25J1/027—Inter-connecting multiple hot equipments upstream of the cold box
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
  • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
  • F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
  • F25J1/0275—Construction and layout of liquefaction equipments, e.g. valves, machines adapted for special use of the liquefaction unit, e.g. portable or transportable devices
  • F25J1/0277—Offshore use, e.g. during shipping
  • F25J1/0278—Unit being stationary, e.g. on floating barge or fixed platform
• • 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
  • F25J2205/00—Processes or apparatus using other separation and/or other processing means
  • F25J2205/02—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum
• • 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
  • F25J2210/60—Natural gas or synthetic natural gas [SNG]
• • 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
  • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
  • F25J2230/22—Compressor driver arrangement, e.g. power supply by motor, gas or steam turbine
• • 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
  • F25J2230/24—Multiple compressors or compressor stages in parallel
• • 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
  • F25J2230/30—Compression of the feed 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
  • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
  • F25J2230/60—Processes or apparatus involving steps for increasing the pressure of gaseous process streams the fluid being hydrocarbons or a mixture of hydrocarbons
• • 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
  • F25J2240/02—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
  • F25J2240/04—Multiple expansion turbines in parallel
• • 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
  • F25J2240/80—Hot exhaust gas turbine combustion engine
• • 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
  • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
  • F25J2245/02—Recycle of a stream in general, e.g. a by-pass 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
  • F25J2270/00—Refrigeration techniques used
  • F25J2270/04—Internal refrigeration with work-producing gas expansion loop
  • F25J2270/06—Internal refrigeration with work-producing gas expansion loop with multiple gas expansion loops
• • 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
  • F25J2270/08—Internal refrigeration by flash gas recovery 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
• • 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
  • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
  • F25J2290/12—Particular process parameters like pressure, temperature, ratios
• • 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
  • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
  • F25J2290/72—Processing device is used off-shore, e.g. on a platform or floating on a ship or barge

Definitions

• the invention relates to the liquefaction of natural gas to form liquefied natural gas (LNG), and more specifically, to the production of LNG in remote or sensitive areas where the construction and/or maintenance of capital facilities, and/or the environmental impact of a conventional LNG plant may be detrimental.
• LNG liquefied natural gas
• LNG production is a rapidly growing means to supply natural gas from locations with an abundant supply of natural gas to distant locations with a strong demand for natural gas.
• the conventional LNG production cycle includes: a) initial treatments of the natural gas resource to remove contaminants such as water, sulfur compounds and carbon dioxide; b) the separation of some heavier hydrocarbon gases, such as propane, butane, pentane, etc.
• Step (c) of the conventional LNG cycle usually requires the use of large refrigeration compressors often powered by large gas turbine drivers that emit substantial carbon and other emissions. Large capital investment in the billions of US dollars and extensive infrastructure are required as part of the liquefaction plant.
• Step (e) of the conventional LNG cycle generally includes re-pressurizing the LNG to the required pressure using cryogenic pumps and then re-gasifying the LNG to pressurized natural gas by exchanging heat through an intermediate fluid but ultimately with seawater or by combusting a portion of the natural gas to heat and vaporize the LNG.
• FLNG floating LNG
• the technology involves the construction of the gas treating and liquefaction facility on a floating structure such as barge or a ship.
• FLNG is a technology solution for monetizing offshore stranded gas where it is not economically viable to construct a gas pipeline to shore.
• FLNG is also increasingly being considered for onshore and near-shore gas fields located in remote, environmentally sensitive and/or politically challenging regions.
• the technology has certain advantages over conventional onshore LNG in that it has a reduced environmental footprint at the production site.
• the technology may also deliver projects faster and at a lower cost since the bulk of the LNG facility is constructed in shipyards with lower labor rates and reduced execution risk.
• FLNG has several advantageous over conventional onshore LNG
• significant technical challenges remain in the application of the technology.
• the FLNG structure must provide the same level of gas treating and liquefaction in an area or space that is often less than one quarter of what would be available for an onshore LNG plant.
• SMR single mixed refrigerant
• DMR dual mixed refrigerant
• expander-based (or expansion) process is a process that reduces the footprint of the liquefaction facility while maintaining its capacity to thereby reduce overall project cost.
• the SMR process has the advantage of allowing all the equipment and bulks associated with the complete liquefaction process to fit within a single FLNG module.
• the SMR liquefaction module is placed on the topside of the FLNG structure as a complete SMR train.
• This "LNG-in-a-Box" concept is favorable for FLNG project execution because it allows for the testing and commissioning of the SMR train at a different location from where the FLNG structure is constructed. It may also allow for the reduction in labor cost since it reduces labor hours at ship yards where labor rates tend to be higher than labor rates at conventional fabrication yards.
• the SMR process has the added advantage of being a relatively efficient, simple, and compact refrigerant process when compared to other mixed refrigerant processes.
• the SMR liquefaction process is typically 15% to 20% more efficient than expander-based liquefaction processes.
• the expander-based process has several advantages that make it well suited for FLNG projects.
• the most significant advantage is that the technology offers liquefaction without the need for external hydrocarbon refrigerants.
• An additional advantage of the expander-based process compared to a mixed refrigerant process is that the expander-based process is less sensitive to offshore motions since the main refrigerant mostly remains in the gas phase.
• application of the expander- based process to an FLNG project with LNG production of greater than 2 million tons per year (MTA) has proven to be less appealing than the use of the mixed refrigerant process.
• MTA million tons per year
• the capacity of an expander-based process train is typically less than 1.5 MTA.
• a mixed refrigerant process train such as that of known dual mixed refrigerant processes, can have a train capacity of greater than 5 MTA.
• the size of the expander-based process train is limited since its refrigerant mostly remains in the vapor state throughout the entire process and the refrigerant absorbs energy through its sensible heat. For these reasons, the refrigerant volumetric flow rate is large throughout the process, and the size of the heat exchangers and piping are proportionately greater than those of a mixed refrigerant process.
• the limitations in compander horsepower size results in parallel rotating machinery as the capacity of the expander-based process train increases.
• the production rate of an FLNG project using an expander-based process can be made to be greater than 2 MTA if multiple expander-based trains are allowed. For example, for a 6 MTA FLNG project, six or more parallel expander- based process trains may be sufficient to achieve the required production. However, the equipment count, complexity and cost all increase with multiple expander trains. Additionally, the assumed process simplicity of the expander-based process compared to a mixed refrigerant process begins to be questioned if multiple trains are required for the expander-based process while the mixed refrigerant process can obtain the required production rate with one or two trains. For these reasons, there is a need to develop a high LNG production capacity FLNG liquefaction process with the advantages of an expander-based process. There is a further need to develop an FLNG technology solution that is better able to handle the challenges that vessel motion has on gas processing.
• United States Patent No. 6,412,302 describes a feed gas expander-based process where two independent closed refrigeration loops are used to cool the feed gas to form LNG.
• the first closed refrigeration loop uses the feed gas or components of the feed gas as the refrigerant.
• Nitrogen gas is used as the refrigerant for the second closed refrigeration loop.
• This technology requires smaller equipment and topside space than a dual loop nitrogen expander-based process.
• the volumetric flow rate of the refrigerant into the low pressure compressor can be 20 to 50% smaller for this technology compared to a dual loop nitrogen expander-based process.
• the technology is still limited to a capacity of less than 1.5 MTA.
• United States Patent No. 8,616,012 describes a feed gas expander-based process where feed gas is used as the refrigerant in a closed refrigeration loop.
• the refrigerant is compressed to a pressure greater than or equal to 1,500 psia (10,340 kPa), or more preferably greater than 2,500 psia (17,240 kPA).
• the refrigerant is then cooled and expanded to achieve cryogenic temperatures.
• This cooled refrigerant is used in a heat exchanger to cool the feed gas from warm temperatures to cryogenic temperatures.
• a subcooling refrigeration loop is then employed to further cool the feed gas to form LNG.
• the subcooling refrigeration loop is a closed loop with flash gas used as the refrigerant.
• This feed gas expander-based process has the advantage of not being limited to a train capacity range of less than 1 MTA. A train size of approximately 6 MTA has been considered.
• the technology has the disadvantage of a high equipment count and increased complexity due to its requirement for two independent refrigeration loops and the compression of the feed gas.
• the high pressure operation also means that the equipment and piping will be much heavier than that of other expander-based processes.
• GB 2,486,036 describes a feed gas expander-based process that is an open loop refrigeration cycle including a precooling expander loop and a liquefying expander loop, where the gas phase after expansion is used to liquefy the natural gas.
• including a liquefying expander in the process significantly reduces the recycle gas rate and the overall required refrigeration power.
• This technology has the advantage of being simpler than other technologies since only one type of refrigerant is used with a single compression string.
• the technology is still limited to capacity of less than 1.5 MTA and it requires the use of liquefying expander, which is not standard equipment for LNG production.
• the technology has also been shown to be less efficient than other technologies for the liquefaction of lean natural gas.
• United States Patent No. 7,386,996 describes an expander-based process with a precooling refrigeration process preceding the main expander-based cooling circuit.
• the precooling refrigeration process includes a carbon dioxide refrigeration circuit in a cascade arrangement.
• the carbon dioxide refrigeration circuit may cool the feed gas and the refrigerant gases of the main expander-based cooling circuit at three pressure levels: a high pressure level to provide the warm-end cooling; a medium pressure level to provide the intermediate temperature cooling; and a low pressure level to provide cold-end cooling for the carbon dioxide refrigeration circuit.
• This technology is more efficient and has a higher production capacity than expander-based processes lacking a pre-cooling step.
• the technology has the additional advantage for FLNG applications since the pre-cooling refrigeration cycle uses carbon dioxide as the refrigerant instead of hydrocarbon refrigerants.
• the carbon dioxide refrigeration circuit comes at the cost of added complexity to the liquefaction process since an additional refrigerant and a substantial amount of extra equipment is introduced.
• the carbon dioxide refrigeration circuit may be in its own module and sized to provide the pre-cooling for multiple expander-based processes. This arrangement has the disadvantage of requiring a significant amount of pipe connections between the pre-cooling module and the main expander-based process modules.
• the "LNG-in-a-Box" advantages discussed above are no longer realized.
• the invention provides a method of producing liquefied natural gas (LNG).
• a natural gas stream is provided from a supply of natural gas.
• the natural gas stream may be compressed in at least two serially arranged compressors to a pressure of at least 2,000 psia to form a compressed natural gas stream.
• the compressed natural gas stream may be cooled to form a cooled compressed natural gas stream.
• the cooled compressed natural gas stream may be expanded in at least one work producing natural gas expander to a pressure that is less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream.
• the chilled natural gas stream may then be liquefied.
• the invention also provides an apparatus for the liquefaction of natural gas.
• At least two serially arranged compressors compress a natural gas stream to a pressure greater than 2,000 psia, thereby forming a compressed natural gas stream.
• a cooling element cools the compressed natural gas stream to form a cooled compressed natural gas stream.
• At least one work-producing expander expands the cooled compressed natural gas stream to a pressure less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream.
• a liquefaction train liquefies the chilled natural gas stream.
• the invention further provides a floating LNG structure, comprising. At least two serially arranged compressors compress a natural gas stream to a pressure greater than 2,000 psia, thereby forming a compressed natural gas stream.
• a cooling element cools the compressed natural gas stream to form a cooled compressed natural gas stream.
• At least one work-producing expander expands the cooled compressed natural gas stream to a pressure less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream.
• a liquefaction train liquefies the chilled natural gas stream.
• FIG. 1 is a schematic diagram of a high pressure compression and expansion (HPCE) module according to disclosed aspects.
• Figure 2 is a graph shown a heating and cooling curve for an expander-based refrigeration process.
• FIG. 3 is a schematic diagram showing an arrangement of single-mixed refrigerant (SMR) liquefaction modules according to known principles.
• SMR single-mixed refrigerant
• Figure 4 is a schematic diagram showing an arrangement of SMR liquefaction modules according to disclosed aspects.
• FIG. 5 is a schematic diagram of an HPCE module according to disclosed aspects.
• Figure 6 is a schematic diagram of an HPCE module and a feed gas expander-based liquefaction module according to disclosed aspects.
• Figure 7 is a flowchart of a method of liquefying natural gas to form LNG according to disclosed aspects.
• compressor means a machine that increases the pressure of a gas by the application of work.
• a “compressor” or “refrigerant compressor” includes any unit, device, or apparatus able to increase the pressure of a gas stream. This includes compressors having a single compression process or step, or compressors having multi-stage compressions or steps, or more particularly multi-stage compressors within a single casing or shell. Evaporated streams to be compressed can be provided to a compressor at different pressures. Some stages or steps of a cooling process may involve two or more compressors in parallel, series, or both.
• the present invention is not limited by the type or arrangement or layout of the compressor or compressors, particularly in any refrigerant circuit.
• cooling broadly refers to lowering and/or dropping a temperature and/or internal energy of a substance by any suitable, desired, or required amount. Cooling may include a temperature drop of at least about 1 °C, at least about 5 °C, at least about 10 °C, at least about 15 °C, at least about 25 °C, at least about 35 °C, or least about 50 °C, or at least about 75 °C, or at least about 85 °C, or at least about 95 °C, or at least about 100 °C.
• the cooling may use any suitable heat sink, such as steam generation, hot water heating, cooling water, air, refrigerant, other process streams (integration), and combinations thereof.
• cooling may be combined and/or cascaded to reach a desired outlet temperature.
• the cooling step may use a cooling unit with any suitable device and/or equipment.
• cooling may include indirect heat exchange, such as with one or more heat exchangers.
• the cooling may use evaporative (heat of vaporization) cooling and/or direct heat exchange, such as a liquid sprayed directly into a process stream.
• expansion device refers to one or more devices suitable for reducing the pressure of a fluid in a line (for example, a liquid stream, a vapor stream, or a multiphase stream containing both liquid and vapor). Unless a particular type of expansion device is specifically stated, the expansion device may be (1) at least partially by isenthalpic means, or (2) may be at least partially by isentropic means, or (3) may be a combination of both isentropic means and isenthalpic means.
• Suitable devices for isenthalpic expansion of natural gas are known in the art and generally include, but are not limited to, manually or automatically, actuated throttling devices such as, for example, valves, control valves, Joule-Thomson (J-T) valves, or venturi devices.
• actuated throttling devices such as, for example, valves, control valves, Joule-Thomson (J-T) valves, or venturi devices.
• Suitable devices for isentropic expansion of natural gas are known in the art and generally include equipment such as expanders or turbo expanders that extract or derive work from such expansion.
• Suitable devices for isentropic expansion of liquid streams are known in the art and generally include equipment such as expanders, hydraulic expanders, liquid turbines, or turbo expanders that extract or derive work from such expansion.
• An example of a combination of both isentropic means and isenthalpic means may be a Joule- Thomson valve and a turbo expander in parallel, which provides the capability of using either alone or using both the J-T valve and the turbo expander simultaneously.
• Isenthalpic or isentropic expansion can be conducted in the all-liquid phase, all-vapor phase, or mixed phases, and can be conducted to facilitate a phase change from a vapor stream or liquid stream to a multiphase stream (a stream having both vapor and liquid phases) or to a single-phase stream different from its initial phase.
• the reference to more than one expansion device in any drawing does not necessarily mean that each expansion device is the same type or size.
• gas is used interchangeably with "vapor,” and is defined as a substance or mixture of substances in the gaseous state as distinguished from the liquid or solid state.
• liquid means a substance or mixture of substances in the liquid state as distinguished from the gas or solid state.
• a "heat exchanger” broadly means any device capable of transferring heat energy or cold energy from one medium to another medium, such as between at least two distinct fluids.
• Heat exchangers include “direct heat exchangers” and “indirect heat exchangers.”
• a heat exchanger may be of any suitable design, such as a co-current or counter-current heat exchanger, an indirect heat exchanger (e.g. a spiral wound heat exchanger or a plate-fin heat exchanger such as a brazed aluminum plate fin type), direct contact heat exchanger, shell-and- tube heat exchanger, spiral, hairpin, core, core-and-kettle, printed-circuit, double-pipe or any other type of known heat exchanger.
• Heat exchanger may also refer to any column, tower, unit or other arrangement adapted to allow the passage of one or more streams therethrough, and to affect direct or indirect heat exchange between one or more lines of refrigerant, and one or more feed streams.
• indirect heat exchange means the bringing of two fluids into heat exchange relation without any physical contact or intermixing of the fluids with each other.
• Core-in-kettle heat exchangers and brazed aluminum plate-fin heat exchangers are examples of equipment that facilitate indirect heat exchange.
• natural gas refers to a multi-component gas obtained from a crude oil well (associated gas) or from a subterranean gas-bearing formation (non- associated gas).
• the composition and pressure of natural gas can vary significantly.
• a typical natural gas stream contains methane (Ci) as a significant component.
• the natural gas stream may also contain ethane (C2), higher molecular weight hydrocarbons, and one or more acid gases.
• the natural gas may also contain minor amounts of contaminants such as water, nitrogen, iron sulfide, wax, and crude oil.
• aspects disclosed herein describe a process for pre-cooling natural gas to a liquefaction process for the production of LNG by the addition of a high pressure compression and high pressure expansion process to the feed gas. More specifically, the invention describes a process where a pretreated natural gas is compressed to pressure greater than 2,000 psia (13,790 kPA), or more preferably greater than 3,000 psia (20,680 kPA). The hot compressed gas is cooled by exchanging heat with the environment to form a compressed pretreated gas.
• the compressed pretreated gas is near-isentropically expanded to a pressure less than 3,000 psia (20,680 kPA), or more preferably to a pressure less than 2,000 psia (13,790 kPA) to form a chilled pretreated gas, where the pressure of the chilled pretreated gas is less than the pressure of the compressed pretreated gas.
• the chilled pretreated gas may be directed to one or more SMR liquefaction trains, or the chilled pretreated gas may be directed to one or more expander- based liquefaction trains where the gas is further cooled to form LNG.
• FIG. 1 is an illustration of an aspect of the pre-cooling process.
• the pre-cooling process is referred to herein as a high pressure compression and expansion (HPCE) process 100.
• the HPCE process 100 may comprise a first compressor 102 which compresses a pretreated natural gas stream 104 to form an intermediate pressure gas stream 106.
• the intermediate pressure gas stream 106 may flow through a first heat exchanger 108 where the intermediate pressure gas stream 106 is cooled by indirectly exchanging heat with the environment to form a cooled intermediate pressure gas stream 110.
• the first heat exchanger 108 may be an air cooled heat exchanger or a water cooled heat exchanger.
• the cooled intermediate pressure gas stream 110 may then be compressed within a second compressor 112 to form a high pressure gas stream 114.
• the pressure of the high pressure gas stream 114 may be greater than 2,000 psia (13,790 kPA), or more preferably greater than 3,000 psia (20,680 kPA).
• the high pressure gas stream 114 may flow through a second heat exchanger 116 where the high pressure gas stream 114 is cooled by indirectly exchanging heat with the environment to form a cooled high pressure gas stream 118.
• the second heat exchanger 116 may be an air cooled heat exchanger or a water cooled heat exchanger.
• the cooled high pressure gas stream 118 may then be expanded within an expander 120 to form a chilled pretreated gas stream 122.
• the pressure of the chilled pretreated gas stream 122 may be less than 3,000 psia (20,680 kPA), or more preferably less than 2,000 psia (13,790 kPA), and the pressure of the chilled pretreated gas stream 122 is less than the pressure of the cooled high pressure gas stream 118.
• the second compressor 112 may be driven solely by the shaft power produced by the expander 120, as indicated by the dashed line 124.
• the SMR liquefaction process may be enhanced by the addition of the HPCE process upstream of the SMR liquefaction process. More specifically, in this aspect, pretreated natural gas may be compressed to a pressure greater than 2,000 psia (13,790 kPA), or more preferably greater than 3,000 psia (20,680 kPA). The hot compressed gas is then cooled by exchanging heat with the environment to form a compressed pretreated gas.
• the compressed pretreated gas is then near-isentropically expanded to pressure less than 3,000 psia (20,680 kPA), or more preferably to a pressure less than 2,000 psia (13,790 kPA) to form a chilled pretreated gas, where the pressure of the chilled pretreated gas is less than the pressure of the compressed pretreated gas.
• the chilled pretreated gas is then directed to multiple SMR liquefaction trains where the chilled pretreated gas is further cooled to form LNG.
• the combination of the HPCE process with SMR trains has several advantages over the conventional SMR process where pretreated natural gas is sent directly to the SMR liquefaction trains.
• the precooling of the natural gas using the HPCE process allows for an increase in LNG production rate within the SMR trains for a given horsepower within the SMR trains.
• SMR trains that are each powered by a gas turbine having an output of about 50 megawatts (MW) can be reduced from five trains producing LNG at 1.5 MTA each to four trains with an increased capacity of 1.9 MTA each.
• the HPCE module has effectively replaced one of the SMR modules.
• the replacement of one SMR module for an HPCE module is advantageous since the HPCE module is expected to be smaller, of less weight, and having significantly lower cost than the SMR module.
• the HPCE module may have an equivalent size gas turbine to provide compression power, and it will also have an equivalent amount of air or water coolers.
• the HPCE module does not have an expensive main cryogenic heat exchanger.
• the vessels and pipes associated with the refrigerant flow within an SMR module are eliminated in the HPCE module.
• Another advantage is that the required storage of refrigerant is reduced since the number of SMR trains has been reduced by one. Also, since a large fraction of the warm temperature cooling of the gas occurs in the HPCE module, the heavier hydrocarbon components of the mixed refrigerant can be reduced. For example, the propane component of the mixed refrigerant may be eliminated without any significant reduction in efficiency of the SMR process.
• the volumetric flow rate of the vaporized refrigerant of the SMR process can be more than 25% less than that of an conventional SMR process receiving warm pretreated gas.
• the lower volumetric flow of refrigerant may reduce the size of the main cryogenic heat exchanger and the size of the low pressure mixed refrigerant compressor.
• the lower volumetric flow rate of the refrigerant is due to its higher vaporizing pressure compared to that of a conventional SMR process.
• Known propane-precooled mixed refrigeration processes and dual mixed refrigeration (DMR) processes may be viewed as versions of an SMR process combined with a pre-cooling refrigeration circuit, but there are significant differences between such processes and aspects of the present disclosure.
• the known processes use a cascading propane refrigeration circuit or a warm-end mixed refrigerant to pre-cool the gas. Both these known processes have the advantage of providing 5% to 15% higher efficiency than the SMR process.
• the capacity of a single liquefaction train using these known processes can be significantly greater than that of a single SMR train.
• the pre-cooling refrigeration circuit of these technologies comes at the cost of added complexity to the liquefaction process since additional refrigerants and a substantial amount of extra equipment is introduced.
• the DMR's disadvantage of higher complexity and weight may outweigh its advantages of higher efficiency and capacity when deciding between and DMR process and SMR process for an FLNG application.
• the known processes have considered the addition of a pre-cooling process upstream of the SMR process as being driven principally by the need for higher thermal efficiencies and higher LNG production capacity for a single train.
• the HPCE process combined with the SMR process has not been realized previously because it does not provide the higher thermal efficiencies that the refrigerant-based precooling process provides.
• the thermal efficiency of the HPCE process with SMR is about the same as a standalone SMR process.
• the disclosed aspects are believed to be novel based at least in part on its description of a pre-cooling process that aims to reduce the weight and complexity of the liquefaction process rather than increase thermal efficiency, which in the past has been the biggest driver for the addition of a pre-cooling process for onshore LNG applications.
• a pre-cooling process that aims to reduce the weight and complexity of the liquefaction process rather than increase thermal efficiency, which in the past has been the biggest driver for the addition of a pre-cooling process for onshore LNG applications.
• footprint, weight, and complexity of the liquefaction process may be a bigger driver of project cost. Therefore the disclosed aspects are of particular value.
• an expander-based liquefaction process may be enhanced by the addition of an HPCE process upstream of the expander-based process. More specifically, in this aspect, a pretreated natural gas stream may be compressed to pressure greater than 2,000 psia (13,790 kPA), or more preferably greater than 3,000 psia (20,680 kPA). The hot compressed gas may then be cooled by exchanging heat with the environment to form a compressed pretreated gas.
• the compressed pretreated gas may be near-isentropically expanded to a pressure less than 3,000 psia (20,680 kPA), or more preferably to a pressure less than 2,000 psia (13,790 kPA) to form a chilled pretreated gas, where the pressure of the chilled pretreated gas is less than the pressure of the compressed pretreated gas.
• the chilled pretreated gas is directed to an expander-based process where the gas is further cooled to form LNG.
• the chilled pretreated gas may be directed to a feed gas expander-based process.
• FIG. 2 shows a typical temperature cooling curve 200 for an expander-based liquefaction process.
• the higher temperature curve 202 is the temperature curve for the natural gas stream.
• the lower temperature curve 204 is the composite temperature curve of a cold cooling stream and a warm cooling stream.
• the cooling curve is marked by three temperature pinch-points 206, 208, and 210.
• Each pinch point is a location within the heat exchanger where the combined heat capacity of the cooling streams is less than that of the natural gas stream. This imbalance in heat capacity between the streams results in reduction in the temperature difference between the cooling stream to the minimally acceptable temperature difference which provides effective heat transfer rate.
• the lowest temperature pinch-point 206 occurs where the colder of the two cooling streams, typically the cold cooling stream, enters the heat exchanger.
• the intermediate temperature pinch-point 208 occurs where the second cooling stream, typically the warm cooling stream, enters the heat exchanger.
• the warm temperature pinch-point 210 occurs where the cold and warm cooling streams exit the heat exchanger.
• the warm temperature pinch-point 210 causes a need for a high mass flow rate for the warmer cooling stream, which subsequently increases the power demand of the expander-based process.
• One proposed method to eliminate the warm temperature pinch-point 210 is to precool the feed gas with an external refrigeration system such as a propane cooling system or a carbon dioxide cooling system.
• an external refrigeration system such as a propane cooling system or a carbon dioxide cooling system.
• United States Patent No. 7,386,996 eliminates the warm temperature pinch-point by using a pre-cooling refrigeration process comprising a carbon dioxide refrigeration circuit in a cascade arrangement.
• This external pre-cooling refrigeration system has the disadvantage of significantly increasing the complexity of the liquefaction process since an additional refrigerant system with all its associated equipment is introduced.
• aspects disclosed herein reduce the impact of the warm temperature pinch-point 210 by precooling the feed gas stream by compressing the feed gas to a pressure greater than 2,000 psia (12,790 kPA), cooling the compressed feed gas stream, and expanding the compressed gas stream to a pressure less than 3,000 psia (20,690 kPA), where the expanded pressure of the feed gas stream is less than the compressed pressure of the feed gas stream.
• This process of cooling the feed gas stream results in a significant reduction in the in the required mass flow rate of the expander-based process cooling streams. It also improves the thermodynamic efficiency of the expander-based process without significantly increasing the equipment count and without the addition of an external refrigerant.
• the expander-based process may be a feed gas expander-based process.
• the feed gas expander-based process may be an open loop feed gas process where the recycling loop comprises a warm-end expander loop and a cold-end expander loop.
• the warm-end expander may discharge a first cooling stream and the cold-end expander may discharge the second cooling stream.
• the temperature of the first cooling stream is higher than the temperature of the second cooling stream.
• the pressure of the first cooling stream is higher than the pressure of the second cooling stream.
• the cold- end expander discharges a two-phase stream that is separated into a second cooling stream and a second pressurize LNG stream.
• a produced natural gas stream may be treated to remove impurities, if present, such as water, heavy hydrocarbons, and sour gases, to make the natural gas suitable for liquefaction.
• the treated natural gas may be directed to the HPCE process where it is compressed to a pressure greater than 2,000 psia (12,790 kPA), or more preferably greater than 3,000 psia (20,680 kPA).
• the hot compressed gas may then be cooled by exchanging heat with the environment to form a compressed treated natural gas.
• the compressed treated natural gas may be near-isentropically expanded to a pressure less than 3,000 psia (20,680 kPA), or more preferably to a pressure less than 2,000 psia (12,790 kPA) to form a chilled treated natural gas, where the pressure of the chilled treated natural gas is less than the pressure of the compressed treated natural gas.
• the chilled treated natural gas may be completely liquefied by indirect exchange of heat with the first cooling stream and the second cooling stream to produce a first pressurized LNG stream.
• the first pressurized LNG stream may be mixed with the second pressurized LNG stream to form a pressurized LNG stream.
• the pressurized LNG stream may be directed to at least one two-phase separation stage where the pressure of the pressurized LNG stream is reduced and the resulting two-phase stream is separated into a flash gas stream and an LNG product stream.
• the flash gas stream may exchange heat with the pressurized LNG stream and the chilled treated natural gas stream prior to being compressed for fuel gas and/or compressed to mix with the recycling second cooling stream.
• the combination of the HPCE process with the feed gas expander-based process has several advantages over a conventional feed gas expander-based process. Including the HPCE process therewith may increase the efficiency of the of the feed gas expander-based process by 20 to 25%.
• the feed-gas expander process of this invention has an efficiency approaching that of an SMR process while still providing the advantages of no external refrigerant use, ease of operation, and reduced equipment count.
• the refrigerant flow rates and the size of the recycle compressors are expected to be significantly lower for the exapander-base process combined with the HPCE process. For these reasons, the production capacity of a single liquefaction train according to disclosed aspects may be greater than 50% above the production capacity of a similarly sized conventional expander-based liquefaction process.
• FIG 3 is an illustration of an arrangement of SMR liquefaction modules on a FLNG 300.
• Natural gas 302 that is pretreated or otherwise suitable for liquefaction may be distributed evenly between five identical or near identical SMR liquefaction modules or trains 304, 306, 308, 310, 312.
• each SMR liquefaction module may receive approximately 50 MW of compression power from either a gas turbine or an electric motor (not shown) to drive the compressors of the SMR liquefaction modules.
• Each SMR liquefaction module may produce approximately 1.5 MTA of LNG for a total stream day production of approximately 7.5 MTA of LNG for the FLNG application.
• FIG 4 is an illustration of an arrangement of an HPCE module 404 with the SMR liquefaction modules or trains 406, 408, 410, 412 on a FLNG 400 according to disclosed aspects.
• Natural gas 402 that is pretreated or otherwise suitable for liquefaction may be directed to the HPCE module 404 to produce a chilled pretreated gas stream 405.
• the HPCE module 404 may receive approximately 50 MW of compression power, for example, from either a gas turbine or an electric motor (not shown) to drive one or more compressors within the HPCE module 404.
• the chilled pretreated gas may be distributed evenly between the four identical or near identical SMR liquefaction modules 406, 408, 410, 412.
• Each SMR liquefaction module may receive approximately 50 MW of compression power from either a gas turbine or an electric motor (not shown) to drive the compressors of the respective SMR liquefaction modules.
• Each SMR liquefaction module may produce approximately 1.9 MTA of LNG for a total stream day production of approximately 7.6 MTA of LNG for the FLNG application.
• FIG. 5 is an illustration of an aspect of the HPCE module 500 referenced in Figure 4.
• a natural gas stream 502 that has been pretreated to remove impurities, or is otherwise suitable for liquefaction, is fed into a first compressor 504 to form a first intermediate pressure gas stream 506.
• the first intermediate pressure gas stream 506 may flow through a first heat exchanger 508 where the first intermediate pressure gas stream 506 is cooled by indirectly exchanging heat with the environment to form a cooled first intermediate pressure gas stream 510.
• the first heat exchanger 508 may be an air cooled heat exchanger or a water cooled heat exchanger.
• the cooled first intermediate pressure gas stream 510 may then be compressed within a second compressor 512 to form a second intermediate pressure gas stream 514.
• the second intermediate pressure gas stream 514 may flow through a second heat exchanger 516 where the second intermediate pressure gas stream 514 is cooled by indirectly exchanging heat with the environment to form a cooled second intermediate pressure gas stream 518.
• the second heat exchanger 516 may be an air cooled heat exchanger or a water cooled heat exchanger.
• the cooled second intermediate pressure gas stream 518 may then be compressed within a third compressor 520 to form a high pressure gas stream 522.
• the pressure of the high pressure gas stream 522 may be greater than 2,000 psia (13,790 kPA), or more preferably greater than 3,000 psia (20,680 kPA).
• the high pressure gas stream 522 may flow through a third heat exchanger 524 where the high pressure gas stream 522 is cooled by indirectly exchanging heat with the environment to form a cooled high pressure gas stream 526.
• the third heat exchanger 524 may be an air cooled heat exchanger or a water cooled heat exchanger.
• the cooled high pressure gas stream 526 may then be expanded within an expander 528 to form a chilled pretreated gas stream 530.
• the pressure of the chilled pretreated gas stream 530 may be less than 3,000 psia (20,680 kPA), or more preferably less than 2,000 psia (13,790 kPA), and the pressure of the chilled pretreated gas stream 530 may be less than the pressure of the cooled high pressure gas stream 526.
• the third compressor 520 may be driven solely by the shaft power produced by the expander 528, as illustrated by line 532.
• FIG. 6 is an illustration of an HPCE process 601 combined with a feed gas expander-based LNG liquefaction process 600.
• Natural gas may be treated to remove impurities, if present, such as water, heavy hydrocarbons, and sour gases, to produce a treated natural gas stream 602 that is suitable for liquefaction.
• the treated natural gas stream 602 may be mixed with a recycled refrigerant gas stream 604 to form a combined stream 606.
• the combined stream 606 may be directed to the HPCE process 601 where the combined streams 606 are compressed within a first compressor 608 to form an intermediate pressure gas stream 610.
• the intermediate pressure gas stream 610 may flow through a first heat exchanger 612 where the intermediate pressure gas stream 610 is cooled by indirectly exchanging heat with the environment to form a cooled intermediate pressure gas stream 614.
• the first heat exchanger 612 may be an air cooled heat exchanger or a water cooled heat exchanger.
• the cooled intermediate pressure gas stream 614 may then be compressed within a second compressor 616 to form a high pressure gas stream 618.
• the pressure of the high pressure gas stream 618 may be greater than 2,000 psia (13,790 kPA), or more preferably greater than 3,000 psia (20,680 kPA).
• the high pressure gas stream 618 may flow through a second heat exchanger 620 where the high pressure gas stream 618 is cooled by indirectly exchanging heat with the environment to form a cooled high pressure gas stream 622.
• the second heat exchanger 620 may be an air cooled heat exchanger or a water cooled heat exchanger.
• the cooled high pressure gas stream 622 may then be expanded within an HPCE expander 624 to form a chilled pretreated gas stream 626.
• the pressure of the chilled pretreated gas stream 626 is less than 3,000 psia (20,680 kPA), or more preferably less than 2,000 psia (13,790 kPA), and where the pressure of the chilled pretreated gas stream 626 is less than the pressure of the cooled high pressure gas stream 622.
• the second compressor 616 may be driven solely by the shaft power produced by the expander 624, as represented by the dashed line 628.
• the chilled pretreated gas stream 626 leaves the HPCE process 601 and is directed to a feed gas expander-based process 600.
• the chilled pretreated gas stream 626 may be separated into a second chilled pretreated gas stream 630, a first refrigerant stream 632, and a second refrigerant stream 634.
• the first refrigerant stream 632 may be expanded in a first expander 636 to produce a first cooling stream 638.
• the first cooling stream 638 enters at least one cryogenic heat exchanger 640 where it exchanges heat with the second chilled pretreated gas stream 630 and the second refrigerant stream 634 to cool said streams.
• the first cooling stream 638 exits the at least one cryogenic heat exchanger 640 as a first warm stream 642.
• the second refrigerant stream 634 after being cooled in the at least one cryogenic heat exchanger 640, may be expanded in a second expander 644 to produce a two-phase stream 646.
• the pressure of the two-phase stream 646 may be the same or may be lower than the pressure of the first cooling stream 638.
• the two-phase stream 646 may be separated into its vapor component and its liquid component in a first two-phase separator 648 to form a second cooling stream 650 and a second pressurized LNG stream 652.
• the temperature of the first cooling stream 638 is higher than the temperature of the second cooling stream 650.
• the second cooling stream 650 enters the at least one cryogenic heat exchanger 640 where it exchanges heat with the second chilled pretreated gas stream 630 and the second refrigerant stream 634 to cool said streams.
• the second cooling stream 650 exits the at least one heat exchanger 640 as a second warm stream 654.
• the second chilled pretreated natural gas stream 630 exchanges heat with the first cooling stream 638 and the second cooling stream 650 to produce a first pressurized LNG stream 656.
• the first pressurized LNG stream 656 may be reduced in pressure in a hydraulic turbine 658 after exiting the at least one heat exchanger 640.
• the first pressurized LNG stream 656 may be mixed with the second pressurized LNG stream 652 to form a combined pressurized LNG stream 660.
• the combined pressurized LNG stream 660 may be directed to a second two-phase separator 662 where the pressure of the combined pressurized LNG stream 660 is reduced, and the resulting two-phase stream is separated into an end flash gas stream 664 and a product LNG stream 667.
• the end flash gas stream 664 may exchange heat with the first pressurized LNG stream 656 within an end flash gas heat exchanger 668 prior to directing the first pressurized LNG stream 656 to the hydraulic turbine 658. Additionally, the end flash gas stream 664 may enter the at least one cryogenic heat exchanger 640 to exchange heat with the second chilled pretreated gas stream 630 and the second refrigerant stream 634 to cool said streams.
• the end flash gas stream 664 exits the at least one heat exchanger 640 as a third warm stream 670.
• the third warm stream 670 may be compressed in a first recycle gas compressor 672 and may exchange heat with the environment in a first recycle heat exchanger 674 to form a first recycle gas stream 676.
• the first recycle gas stream 676 may be combined with the second warm stream 654 and, together, may be compressed in a second recycle gas compressor 678, and may exchange heat with the environment in a second recycle heat exchanger 680 to form a second recycle gas stream 682.
• the second recycle gas stream 682 may be combined with the first warm stream 642 and, together, may be compressed in third and fourth recycle gas compressors 684, 686 and may exchange heat with the environment in a third recycle heat exchanger 688 to form the recycle refrigerant gas stream 604.
• the third recycle gas compressor 684 may be driven solely by the shaft power produced by the first expander 636, as shown by the dashed line 690.
• the fourth recycle gas compressor 686 may be driven solely by the shaft power produced by the second expander 644, as shown by the dashed line 692.
• FIG. 7 illustrates a method 700 of producing LNG according to disclosed aspects.
• a natural gas stream may be provided from a supply of natural gas.
• the natural gas stream may be compressed in at least two serially arranged compressors to a pressure of at least 2,000 psia to form a compressed natural gas stream.
• the compressed natural gas stream may be cooled to form a cooled compressed natural gas stream.
• the cooled compressed natural gas stream may be expanded in at least one work producing natural gas expander to a pressure that is less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream.
• the chilled natural gas stream may be liquefied.
• Disclosed aspects may include any combinations of the methods and systems shown in the following numbered paragraphs. This is not to be considered a complete listing of all possible aspects, as any number of variations can be envisioned from the description above.
• a method of producing liquefied natural gas comprising: providing a natural gas stream from a supply of natural gas;
• cooling the compressed natural gas stream to form a cooled compressed natural gas stream expanding, in at least one work producing natural gas expander, the cooled compressed natural gas stream to a pressure that is less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream; and liquefying the chilled natural gas stream.
• the chilled natural gas stream is a first chilled natural gas stream, and further comprising separating the first chilled natural gas stream into a second chilled natural gas stream, a first refrigerant stream, and a second refrigerant stream.
• cooling the compressed natural gas stream comprises cooling the compressed natural gas stream in at least one heat exchanger that exchanges heat with the environment.
• An apparatus for the liquefaction of natural gas comprising: at least two serially arranged compressors configured to compress a natural gas stream to a pressure greater than 2,000 psia, thereby forming a compressed natural gas stream;
• a cooling element configured to cool the compressed natural gas stream, thereby forming a cooled compressed natural gas stream
• At least one work-producing expander configured to expand the cooled compressed natural gas stream to a pressure less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream;
• a liquefaction train configured to liquefy the chilled natural gas stream.
• the liquefaction train comprises one of a single mixed refrigerant (SMR) liquefaction module and an expander-based liquefaction module.
• SMR single mixed refrigerant
• the expander-based liquefaction module is one of a nitrogen gas expander-based liquefaction module and a feed gas expander- based liquefaction module.
• feed gas expander-based liquefaction module is an open loop feed gas expander-based liquefaction module.
• the chilled natural gas stream is a first chilled natural gas stream that is separated into a second chilled natural gas stream, a first refrigerant stream, and a second refrigerant stream.
• feed gas expander-based liquefaction module comprises:
• a warm-end expander configured to expand the first refrigerant stream to form a first cooling stream discharged therefrom, the first cooling stream having a first temperature
• a cold-end expander configured to expand the second refrigerant stream to form one of a second cooling stream and a two-phase stream discharged therefrom, the second cooling stream having a second temperature
• cooling element comprises a heat exchanger configured to cool the compressed natural gas stream by exchanging heat with the environment.
• a floating LNG structure comprising: at least two serially arranged compressors configured to compress a natural gas stream to a pressure greater than 2,000 psia, thereby forming a compressed natural gas stream;
• a cooling element configured to cool the compressed natural gas stream, thereby forming a cooled compressed natural gas stream
• At least one work-producing expander configured to expand the cooled compressed natural gas stream to a pressure less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream;
• a liquefaction train configured to liquefy the chilled natural gas stream.

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• 2016
  • 2016-11-10 CA CA3005327A patent/CA3005327C/en active Active
  • 2016-11-10 WO PCT/US2016/061335 patent/WO2017105687A1/en active Application Filing
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  • 2016-11-10 US US15/348,533 patent/US20170167786A1/en not_active Abandoned
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• 2020
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