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
  • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
  • F25J1/0228—Coupling of the liquefaction unit to other units or processes, so-called integrated processes
  • F25J1/0235—Heat exchange integration
  • F25J1/0236—Heat exchange integration providing refrigeration for different processes treating not the same 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
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
  • F25J1/0022—Hydrocarbons, e.g. natural gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
  • F25J1/0047—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle
  • F25J1/0052—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle by vaporising a liquid refrigerant stream
  • F25J1/0055—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using an "external" refrigerant stream in a closed vapor compression cycle by vaporising a liquid refrigerant stream originating from an incorporated cascade
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
  • F25J1/008—Hydrocarbons
  • F25J1/0087—Propane; Propylene
• • 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
  • F25J1/0214—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 dual level refrigeration cascade with at least one MCR cycle
  • F25J1/0215—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 dual level refrigeration cascade with at least one MCR cycle with one SCR cycle
  • F25J1/0216—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 dual level refrigeration cascade with at least one MCR cycle with one SCR cycle using a C3 pre-cooling 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
  • F25J1/0243—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
  • F25J1/0287—Combination of different types of drivers mechanically coupled to the same refrigerant compressor, possibly split on multiple compressor casings including an electrical motor
• • 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.
  • F25J1/029—Mechanically coupling of different refrigerant compressors in a cascade refrigeration system to a common 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.
  • F25J1/0292—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.
  • F25J1/0294—Multiple compressor casings/strings in parallel, e.g. split arrangement
• • 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

Definitions

• the present invention relates to technologies for the liquefaction of natural gas and in particular a cooling circuit to be used in the liquefaction of natural gas .
• the liquefaction of natural gas is normally used for making the transportation and storage of the same more convenient.
• the present invention relates in particular to the liquefaction technology of natural gas known with the name of C3-MR, i.e. propane-mixed refrigerant.
• a pre-cooling cycle with a pure cooling fluid i.e. propane (C3)
• MR cooling fluids
• the propane cycle develops on three or four pressure levels and has the function of pre-cooling the natural gas to temperatures ranging from -30°C to -40°C.
• This cycle has the additional function of cooling and partially liquefying the mixed refrigerant, hereinafter MR, used in the second cycle.
• the heat exchangers used for this cycle are of the tube-bundle kettle type, in which the propane on evaporating on the shell side cools the hot fluid which is flowing in the pipes.
• MCHE main cryogenic heat exchanger
• the compressors of the cooling cycles are operated by large gas turbines or, less frequently, by vapour turbines or electric motors.
• split-MRTM conceived by the company APCI (Air Products & Chemicals Int.), wherein a portion of the power required for the compression of the mixed refrigerant is provided by the same turbine used for the compression of propane.
• This configuration allows full use of the power of gas turbines and minimizes the number of turbines present in the cooling circuit.
• the Split-MRTM configuration enables a production capacity of about 5 MTPA per year, to the detriment, however, of the operative flexibility.
• the compressors rotate at a constant rpm and lie on two shafts entrained by respective gas turbines of the heavy-duty type .
• the Split-MRTM configuration therefore allows the exploitation of the power of gas turbines to be optimized, to the detriment, however, of the operative flexibility of the circuit.
• An objective of the present invention is to overcome the drawbacks of the known art and in particular to provide an alternative configuration of the machines present in a natural gas cooling plant.
• an objective of the present invention is to provide a cooling circuit for a natural gas liquefaction plant which allows an increase in the annual production, mitigating the bottleneck generated during hot periods .
• a further objective of the present invention is to provide a cooling circuit for a liquefaction plant of natural gas which allows an increase in the annual production .
• Another objective of the present invention is to provide a cooling circuit for a liquefaction plant of natural gas which allows a reduction in the consumption of natural gas required by the plant.
• An additional objective of the present invention is to provide a cooling circuit for a liquefaction plant of natural gas which allows the plant flexibility to be increased on the basis of the operability of the cooling compressors installed in parallel.
• a further objective of the present invention is to provide a cooling circuit for a liquefaction plant of natural gas which allows to have a further cooling capacity to be used for the extraction of heavy components of natural gas (LPG/gasoline) , increasing the flexibility of the plant with respect to the quality and composition of the natural gas at the inlet.
• LPG/gasoline heavy components of natural gas
• a cooling circuit for a liquefaction plant of natural gas comprising:
• pre-cooling system of natural gas and mixed refrigerant comprising two parallel compression lines of propane, each having a first compressor activated by a first gas turbine;
• a liquefaction system of natural gas comprising three parallel compression lines of the mixed refrigerant, each having a second compressor activated by a second gas turbine.
• said first and second gas turbines can be of the aeroderivative type and the same as each other .
• Said mixed refrigerant can be a mixture of propane, ethane, methane and nitrogen.
• the air at the inlet of said second gas turbines of said liquefaction system of natural gas can be cooled by a portion of cooling power provided by said pre- cooling system.
• a portion of cooling power provided by said pre- cooling system can be used for increasing the extraction of heavy components of natural gas, such as LPG and gasoline.
• Said second compressor can comprise a third compressor for effecting a first compression step of the mixed refrigerant at low/medium pressure, and a fourth compressor for effecting a second compression step of the mixed refrigerant at high pressure, situated in series with respect to each other.
• Said first compressor can divide the propane compression into three or four compression steps at different pressure levels.
• figure 1 is a schematic view of a cooling circuit for a liquefaction plant of natural gas having two compression lines of propane and three compression lines of mixed refrigerant;
• FIG. 2 is a schematic view of a cooling circuit of the Split-MRTM type, for a liquefaction plant of natural gas;
• figure 3 is a schematic view of a preferred embodiment of two compression lines of propane and three compression lines of mixed refrigerant;
• figure 4 is a graph relating to the yields of the liquefaction plant of natural gas, during various months of the year.
• this shows a cooling circuit 100 for a liquefaction plant of natural gas.
• said liquefaction plant of natural gas is schematized in its two main sub-systems: the pre-cooling system 105, which cools the natural gas introduced into the plant to a temperature ranging from -30°C to -40°C, and the liquefaction system 106, which liquefies and sub-cools the pre-cooled gas to a temperature ranging from -145°C to -160°C.
• the natural gas is first pre-cooled in a pre- cooling system comprising two parallel compression lines of propane, each having a first compressor 102 activated by a first gas turbine 101' .
• Said system is also configurated to pre-cool the mixed refrigerant used in the liquefaction system 106.
• the cooled natural gas is subsequently liquefied and sub-cooled in a liquefaction system of natural gas comprising three parallel lines for the compression of the mixed refrigerant, each having a second compressor 103 activated by a second gas turbine 101".
• the pre-cooling system 105 fed by the two compression lines of propane, allows the cooling of natural gas to a temperature ranging from -30°C to -40°C.
• the liquefaction system 106 fed by the three compression lines of the mixed refrigerant, allows a further removal of heat from the natural gas, transforming said natural gas into liquid natural gas (LNG) .
• LNG liquid natural gas
• Said first gas turbines 101' are preferably of the medium-sized aeroderivative type, for example with a power ranging from 30 MW to 60 MW.
• Said second gas turbines 101" are preferably also of the medium-sized aeroderivative type, for example with a power ranging from 30 MW to 60 MW.
• Said compression lines of propane or mixed refrigerant are in parallel with respect to each other and provide an autonomous contribution to the heat removal from the natural gas.
• each of said lines comprises at least one compressor 102 or 103, operated by a gas turbine 101' or 101", for compressing a refrigerant suitable for expanding in the pre-cooling system 105 or in the liquefaction system 106.
• the power absorbed for the compression of propane is equal to about 35% of the total power required, whereas the power absorbed for the compression of the mixed refrigerant is equal to about 65% of the total power required.
• aeroderivative gas turbines 101, 101" positioned in parallel and the same as each other, are used for providing the power necessary for activating said compressors 102 and 103, of which two (101') are destined for activating said first compressors 102 of propane and three (101") for activating said second compressors 103 of mixed refrigerant.
• This configuration of the compression lines allows the first two gas turbines 101' to make two fifths of the total power installed available, i.e. 40%, against a power requirement on the part of said compressors 102 equal to about 35% of the total power required.
• This relationship between the power required by said first and second compressors 102, 103 and the total power available and supplied by said first and second gas turbines 101', 101", allows the generation of an additional cooling power in the pre-cooling system 105. This additional cooling power can be used for cooling the air at the inlet to said second gas turbines 101".
• said second centrifugal compressor 103 in order to compress the mixed refrigerant in the liquefaction system of natural gas, preferably comprises a third compressor 103' , for effecting a first compression step of the mixed refrigerant at low/medium pressure, and a fourth compressor 103" for effecting a second compression step of the mixed refrigerant at high pressure, situated in series with respect to each other.
• Said low/medium pressure level can range from 20 to 35 bar.
• Said high pressure level can range from 55 to 65 bar.
• a first heat exchanger 109' is installed between said third compressor 103' and said fourth compressor 103", suitable for absorbing heat from the mixed refrigerant after the first compression step, and a second heat exchanger 109" for absorbing additional heat from the mixed refrigerant after the second compression step.
• said third and fourth compressors 103' , 103" are preferably selected so as to make full use of the power that can be supplied by said second gas turbine 101".
• said first compressor 102 divides the propane compression into three or four compression steps at different pressure levels.
• two first compressors 102 of the centrifugal type may be installed, each activated by a first gas turbine 101'.
• the power absorbed by said first compressors 102 follows that absorbed by said third and fourth compressors 103' , 103" associated with the lines of the mixed refrigerant, and the process parameters relating to the natural gas to be liquefied.
• the power absorbed by said first compressors 102 normally ranges from 80 % to 100% of the total power that can be supplied by said first gas turbines 101', depending on the environmental conditions.
• the power necessary for activating a fifth compressor 112 of propane and a sixth compressor 113 at high pressure of mixed refrigerant is provided by a first traditional gas turbine 116 of the heavy-duty type, and the power necessary for activating a seventh compressor 114 at low pressure and an eighth compressor 115 at medium pressure, is provided by a second traditional gas turbine 117 of the heavy-duty type.
• Said traditional gas turbines 116, 117 have an ISO nominal power of 86.2 MW equal to a power supplied at 25°C of about 72 MW, and a constant number of revolutions of the shaft.
• said compressor 112 of propane provides the cooling power necessary for pre-cooling the natural gas in said pre-cooling system 105
• said compressors 113, 114, 115 arranged in series with respect to each other, provide the cooling power necessary for liquefying and sub-cooling the natural gas in said liquefaction system 106.
• Said traditional gas turbines 116, 117 of the heavy-duty type are of the single-shaft type and preferably require large-sized auxiliary motors 111', 111" for the start-up. These motors are necessary in the start-up phase for activating the gas turbines and bringing them to a rev regime which allows them to be self-sustained.
• Said auxiliary motors 111', 111" are also used for producing additional power to that supplied by the gas turbines, so as to allow a higher potentiality of the cooling circuits.
• auxiliary motors 111', 111" are installed on respective common turbine shafts and compressors, and have a power of about 20 MW each.
• the compression lines of both propane and mixed refrigerant are in parallel in order to prevent the failure of a gas turbine or compressor from leading to the stoppage of the whole liquefaction plant.
• gas turbines of the aeroderivative type moreover, allows the number of revs of the turbine to be regulated and consequently the power supplied in relation to the load and functioning conditions of the remaining components of the circuit.
• the possibility of regulating the speed of these aeroderivative gas turbines and their arrangement on parallel compression lines, allows maintenance interventions to be effected without stopping the cooling circuit. In this way, the availability of the plant is maximized.
• Said gas turbines of the aeroderivative type are also more compact with respect to the common industrial gas turbines of the heavy-duty type, thus reducing the overall footprint of the cooling circuit.
• a further advantage in the use of gas turbines of the aeroderivative type lies in the fact that this type of turbine has a lower gas consumption with respect to common alternative solutions.
• the cooling circuit in accordance with the present invention allows some of the equipment installed in said plant according to the Split-MRTM configuration, to be eliminated.
• said auxiliary motors 111', 111" of the Split-MRTM scheme are not necessary in the scheme proposed according to the present invention.
• Said portion of cooling power in excess provided by the pre-cooling system can be used for cooling the air at the inlet of said second gas turbines 101".
• the power a turbine can supply is inversely proportional to the temperature of the air at the inlet of the turbine, and, on increasing the temperature of the air at the inlet, its volume increases and the yield of the turbine decreases.
• auxiliary exchangers 104 pre-cool the air using the cooling power of the propane circuit.
• the heat exchange preferably, but not necessarily, takes place through the use of an intermediate coolant.
• figure 4 shows a first curve 401 relating to the yields of a plant configured according to the logic of aeroderivative turbines in parallel without pre-cooling the air at the inlet, and a second curve 402 relating to the yields of the same plant configured according to the logic of aeroderivative turbines in parallel and comprising said auxiliary exchangers 104 for pre-cooling the air at the inlet of said second gas turbines 101".
• This benefit can be mainly obtained in places where the temperature exceeds 20°C for many months of the year .
• the number of compressors and the number of turbines increases, with the advantage of having a longer average availability of the plant.
• an availability of a natural gas liquefaction plant can be obtained of about 5 ⁇ 10 days/year higher than that obtainable with a plant equipped with two heavy-duty turbines model Frame 7 installed according to the Split-MRTM logic.
• Said mixed refrigerant can be a mixture of methane, nitrogen, ethane, ethylene, propane, propylene, butane and pentanes.

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

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• 2012
  • 2012-09-28 IT IT001625A patent/ITMI20121625A1/it unknown
• 2013
  • 2013-09-20 AU AU2013322818A patent/AU2013322818A1/en not_active Abandoned
  • 2013-09-20 JP JP2015533543A patent/JP6329154B2/ja active Active
  • 2013-09-20 WO PCT/EP2013/069553 patent/WO2014048845A1/en active Application Filing
  • 2013-09-20 AP AP2015008323A patent/AP2015008323A0/xx unknown
• 2018
  • 2018-03-27 AU AU2018202194A patent/AU2018202194A1/en not_active Abandoned

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