AU2005202956A1 - Method for the liquefaction of a hydrocarbon-rich stream - Google Patents

Method for the liquefaction of a hydrocarbon-rich stream Download PDF

Info

Publication number
AU2005202956A1
AU2005202956A1 AU2005202956A AU2005202956A AU2005202956A1 AU 2005202956 A1 AU2005202956 A1 AU 2005202956A1 AU 2005202956 A AU2005202956 A AU 2005202956A AU 2005202956 A AU2005202956 A AU 2005202956A AU 2005202956 A1 AU2005202956 A1 AU 2005202956A1
Authority
AU
Australia
Prior art keywords
mixed
refrigerant
hydrocarbon
cooling
stream
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
AU2005202956A
Inventor
Heinz Bauer
Hubert Franke
Pentti Paurola
Rainer Sapper
Rudolf Stockmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linde GmbH
Equinor ASA
Original Assignee
Linde GmbH
Statoil ASA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linde GmbH, Statoil ASA filed Critical Linde GmbH
Publication of AU2005202956A1 publication Critical patent/AU2005202956A1/en
Abandoned legal-status Critical Current

Links

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"
    • F25J1/0042—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
    • F25J1/0052—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
    • 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
    • F25J1/003—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
    • F25J1/0057—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 after expansion of the liquid 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
    • F25J1/02—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
    • 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.
    • F25J1/0292—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.
    • F25J1/0295—Shifting of the compression load between different cooling stages within a refrigerant cycle or within a cascade refrigeration system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
    • F25J1/0296—Removal of the heat of compression, e.g. within an inter- or afterstage-cooler against an ambient heat sink
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • 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.
    • F25J1/0298—Safety aspects and control of the refrigerant compression system, e.g. anti-surge control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
    • F25J2220/64—Separating heavy hydrocarbons, e.g. NGL, LPG, C4+ hydrocarbons or heavy condensates in general
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • 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

Landscapes

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

Description

AUSTRALIA
PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S):: Linde Aktiengesellschaft AND Statoil ASA ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Nicholson Street, Melbourne, 3000, Australia INVENTION TITLE: Method for the liquefaction of a hydrocarbon-rich stream The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5102 CDescription NThe invention relates to a method for the liquefaction of a hydrocarbon-rich Cstream, in particular a natural gas stream, the liquefaction of the hydrocarbon-
(N
Orich stream taking place against a mixed-refrigerant cascade cycle consisting of S 10 two mixed-refrigerant cycles, and the first mixed-refrigerant cycle being used for 0 the pre-cooling and the second mixed-refrigerant cycle for the liquefaction and sub-cooling of the hydrocarbon-rich stream to be liquefied.
The term "pre-cooling" should be understood hereinafter to mean the cooling of the hydrocarbon-rich stream to be liquefied to a temperature at which the separation of heavy or higher-boiling hydrocarbons takes place. The subsequent, further cooling of the hydrocarbon-rich stream to be liquefied is then designated by the term "liquefaction".
A so-called single-flow natural gas liquefaction method is known from the German patent application 197 22 490. In this method the cooling, liquefaction and sub-cooling of the natural gas stream is effected against only one mixedrefrigerant cycle. The compressed mixed refrigerant is partially condensed preferably against air or cooling water and separated into a lower-boiling gas fraction and a higher-boiling liquid fraction. The two fractions are then supplied at different pressure levels to the heat exchanger or heat exchangers in which the natural gas stream to be liquefied is cooled and liquefied.
Such single-flow liquefaction methods can be operated economically only for capacities up to a maximum of 1 mtpa. For liquefaction outputs in the range from 1 to 5 mtpa, so-called dual-flow liquefaction methods are generally used.
A generic dual-flow liquefaction method is known, for example, from the postpublished German patent application 10 2004 011 483. It has been shown, Nhowever, that especially in the range of relatively small capacities from 1 to 3 Smtpa the known dual-flow natural gas liquefaction methods are in need of N improvement.
0 ID 5 With the citation of the two above-mentioned German patent applications their disclosures are to be included in their entirety in the disclosure of the present patent application.
SIt is the object of the present invention to specify a generic method for the liquefaction of a hydrocarbon-rich stream which can be operated more economically than the known liquefaction methods, in particular in the abovementioned range of relatively small capacities.
This object is achieved by a generic liquefaction method which is characterised in that the first mixed-refrigerant cycle is separated into a lower-boiling gas fraction and a higher-boiling liquid fraction and both fractions are supplied to the pre-cooling section at different pressures.
The method according to the invention and further embodiments thereof, which are provided by the dependent claims, will be elucidated in more detail below with reference to the embodiment represented in the Figure.
As shown in the Figure, the hydrocarbon-rich stream to be liquefied is supplied via line a to a heat exchanger El. In the latter the hydrocarbon-rich stream to be liquefied is cooled until the heavy or higher-boiling hydrocarbons contained therein condense and can be separated from the hydrocarbon-rich stream in the separation unit H, to which the cooled stream being processed is supplied via the line b. The hydrocarbons separated are drawn off via line c and optionally supplied to a further use.
If heavy hydrocarbons are contained in the natural gas stream to be liquefied, they are separated between pre-cooling and liquefaction and drawn off as a so- N called NGL (Natural Gas Liquids) fraction and, if applicable, are supplied to a Sfurther processing stage. The components of the hydrocarbon-rich stream or N natural gas to be liquefied which would freeze out in the subsequent cooling and
O
liquefaction i.e. C5+ hydrocarbons and aromatic compounds are referred to as D 5 heavy or higher-boiling hydrocarbons. In addition, the hydrocarbons which would increase the calorific value of the liquefied natural gas to an undesired degree Sin particular, propane and butane are referred to here are often separated before liquefaction.
This separation of higher-boiling hydrocarbons is usually effected in that there is provided a so-called HHC (Heavy Hydrocarbon) column or scrubbing column that is used to separate the heavy hydrocarbons and benzene from the hydrocarbon-rich stream to be liquefied. In principle, the method according to the invention can be combined with all known separation methods for higher-boiling hydrocarbons comprising the state of the art.
The hydrocarbon-rich stream, now freed from the higher-boiling hydrocarbons, is supplied via the line d to a second heat exchanger E2 in which it is liquefied and sub-cooled against the mixed refrigerant of the second mixed-refrigerant cycle.
The liquefied and sub-cooled hydrocarbon-rich stream is drawn off from the heat exchanger E2 via the line e, is optionally decompressed in a decompression turbine T1 and then supplied directly to a further use or (temporary) storage via the valve f and the line g.
The pre-cooling of the hydrocarbon-rich stream to be liquefied in the heat exchanger El is now carried out according to the invention against a (first) mixed-refrigerant cycle which is separated into a lower-boiling gas fraction and a higher-boiling liquid fraction, the two fractions being supplied at different pressures to the heat exchanger El.
For this purpose the mixed refrigerant drawn off from the heat exchanger El via the line 5 is compressed to an intermediate pressure in the first compressor c stage of the two-stage compressor V1, is partially condensed against ambient air or another, suitable medium in the heat exchanger E3 and then supplied to a IDfirst separator D via line 1.
ID 5 A higher-boiling liquid fraction is drawn off from the settling basin of the separator D via line 2 and supplied to the heat exchanger El. The liquid fraction sub-cooled against itself in the heat exchanger El is drawn off from the heat n exchanger El via line 3 and decompressed in the decompression valve 4. On completion of vaporisation in the heat exchanger El this mixed refrigerant part stream is supplied to the first compressor stage of the compressor V1 via the line already mentioned.
A gas fraction is drawn off from the head of the separator D via line 6 and compressed to the desired final pressure in the second compressor stage of the compressor V1. The compressed mixed-refrigerant stream is partially condensed also against ambient air or another, suitable medium in the heat exchanger E3' and supplied to a second separator D' via line 7.
The liquid fraction accumulating in the settling basin of the separator D' is fed back into the first separator D via line 8, in which a decompression valve 9 is provided. The lower-boiling gas fraction obtained at the head of the separator D' is supplied to the heat exchanger El via line 10, is cooled therein and, after passing through the heat exchanger El, is supplied to a decompression valve 12 via line 11. In the decompression valve 12 the part stream of mixed refrigerant is decompressed and then again supplied to the heat exchanger El and vaporised therein, before being supplied via the line 5 already mentioned to the first compressor stage of the compressor V1.
In a development of the method according to the invention it is proposed that the pre-cooling of the hydrocarbon-rich stream a preferably takes place in a spiral heat exchanger El.
O
N Through their construction, spiral heat exchangers have only one flow in their Scasing but optionally a plurality of flows in their tubes. A procedure in which all I the part streams of the refrigerant (mixture) are vaporised at a common pressure 0 in the casing can therefore be simply realised. The vaporisation of part streams of refrigerant (mixture) at different pressures requires separate apparatuses when spiral heat exchangers are used. In addition, the pipework of spiral heat Sexchangers is simpler to construct than that of complex plate exchanger configurations.
The compressed mixed refrigerant of the second mixed-refrigerant cycle which is used to liquefy and sub-cool the natural gas flow to be liquefied is first fed to an after-cooler E4 via line 20 and then via line 21 to the heat exchanger El, where it is condensed. The liquefied mixed refrigerant flow is then supplied via line 22 to the heat exchanger E2 where it is further sub-cooled, is decompressed in the optional decompression turbine T2 after passing through the heat exchanger E2 and is then supplied via line 23 to a decompression valve 24 where it is decompressed. The second part stream of mixed refrigerant is then supplied, after vaporisation in the heat exchanger E2, to the intake stage of the recirculation compressor V2 via line The heat exchanger E2 may be in the form of a spiral heat exchanger or a plate heat exchanger. If the liquefaction and sub-cooling of the hydrocarbon-rich stream to be liquefied take place in a plate heat exchanger, the mixed refrigerant of the second mixed-refrigerant cycle may according to an advantageous embodiment of the method according to the invention be vaporised in a rising or descending manner.
According to the invention the cooling, liquefaction and sub-cooling of the natural gas stream to be liquefied now take place against two mixed-refrigerant cycles, the mixed-refrigerant cycle used for pre-cooling being separated into a lowerboiling gas fraction and a higher-boiling liquid fraction, and the two fractions being supplied to the pre-cooling section at different pressures.
SIt has been found that, as compared to a single-flow liquefaction method, the I energy consumption of the method according to the invention can be reduced by
O
to 20%. The method according to the invention is therefore especially suited to plant capacities in the range from 1 to 3 mtpa.
SIn dual-flow LNG plants the circuit compressor is usually driven by gas turbines.
These in turn are usually put into operation by means of electrical or steamdriven starters. Because such starters must often have considerable power- to 40% of the gas turbine power they are used as so-called helpers to support the gas turbines during normal operation. Relatively large gas turbines are available on the market only in discrete power steps with relatively large power jumps. The power of the starters or helpers in relation to the gas turbine power is limited to avoid synchronisation problems.
Because of a large number of technical factors such as the composition and pressure of the hydrocarbon-rich stream to be liquefied, ambient temperature, etc., and the possible requirement for the separation of heavy hydrocarbons, an optimum distribution of power between the compressor drives of the two mixedrefrigerant cycles cannot be achieved, or is achieved only accidentally. Typically, the first or pre-cooling cycle requires approximately 40 to 55% of the total energy. In addition, the power requirement of the pre-cooling cycle is often less than that of the second or liquefaction cycle.
This asymmetry can be equalised out by a different use of the helpers. For example, if the power distribution between the first and second mixed-refrigerant cycles is 45% to 55% and each of the two mixed-refrigerant cycles has a gas turbine with a power of 35 MW and a helper with a power of 10 MW, the helper of the first refrigeration cycle is operated at only 2 MW instead of the possible A major part of the investment for this helper is therefore unutilised during normal liquefaction operation.
c In view of the limitation, already mentioned, of the starter or helper power in relation to the gas turbine power it is obvious that the full utilisation of both IDhelpers now achieved leads to a maximisation of plant capacity. This will be 0 elucidated with reference to the following example.
IO If a power distribution of 50% to 50% between the first and second mixedrefrigerant cycles is achieved assuming identical gas turbines and n starters/helpers for both refrigeration cycles these pieces of equipment and the investment for them can be fully utilised. Returning to the example referred to above, the starter/helper of the second refrigeration cycle can now be operated at a power of 10 MW. As compared to the initial state first mentioned, the usable installed power is increased from 82 MW to 90 MW by the method according to the invention. With a given drive concept the plant output can therefore be increased by approximately The recirculation compressor V2, which is a cold-intake compressor and preferably has a pressure ratio of at least 10:1, is driven like the recirculation compressor V1 by a gas turbine G2; starters/helpers (not shown in the Figure) are associated with the gas turbines G1 and G2.
A partially-compressed mixed-refrigerant stream is drawn off from an intermediate stage of the recirculation compressor V2 via line 26, subjected to after-cooling at E5 and then supplied at least partially via line 29 to the heat exchanger El and intermediately cooled therein against the first refrigeration cycle. The intermediately cooled, partially compressed mixed-refrigerant stream is then again supplied via line 30 to a suitable intermediate pressure stage of the compressor V2 and compressed to the desired final pressure.
By means of the line 27, in which a valve 28 is provided for proportional distribution, the quantity of the partially compressed mixed-refrigerant stream supplied via line 29 to the heat exchanger El can be regulated.
CI The use of the first refrigeration cycle for intermediate cooling of the second Srefrigeration cycle reduces the load on the latter at the expense of the first I refrigeration cycle, since the compressor power of the high-pressure section of
O
the compressor V2 is reduced proportionally to the now lower intake temperature of the intermediately cooled refrigerant stream in line 30. The outputs of the compressors can now be shifted until output is equalised between the two acompressors V1 and V2 and their associated starters/helpers.
OThe optimal selection of the above-described intermediate cooling is determined by the dew point of the mixed refrigerant chosen for the second refrigeration cycle with the chosen intermediate pressure at which the mixed refrigerant is drawn off. Ideally, a part quantity of the mixed refrigerant of the second refrigeration cycle is cooled by means of the first refrigeration cycle until the outputs of the two cycle drives V1 and V2 have been equalised.
Because the first mixed-refrigerant cycle is now used for intermediate cooling of the second mixed-refrigerant cycle, the installed power of identical gas turbines and starters/helpers can be utilised to the full.
A further embodiment (not shown in the Figure) of the method according to the invention, which is only used if separation of higher-boiling hydrocarbons is carried out after the pre-cooling of the hydrocarbon-rich stream to be liquefied, is characterised in that a part stream of the mixed refrigerant of the second mixedrefrigerant cycle is supplied to the separation unit H for cooling purposes and is then vaporised at a higher pressure than the remaining mixed-refrigerant stream of the second mixed-refrigerant cycle. The mixed-refrigerant stream supplied to the separation unit H is therefore supplied after its vaporisation to the second compressor V2 at a suitable intermediate pressure.
The disadvantage of the method according to the invention for the liquefaction of a hydrocarbon-rich stream is that it requires higher investment than a single-flow 9 C liquefaction method and, in addition, requires more complex and expensive control technology.
The reference numerals in the following claims do not in any way limit the scope of the respective claims.
IND Throughout this specification and the claims which follow, V)unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will CI be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of Sany other integer or step or group of integers or steps.
SThe reference to any prior art in this specification is not, I and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (5)

1. Method for the liquefaction of a hydrocarbon-rich stream, in particular a natural gas stream, the liquefaction of the hydrocarbon-rich stream taking O 5 place against a mixed-refrigerant cascade cycle consisting of two mixed- refrigerant cycles and the first mixed-refrigerant cycle being used for the Spre-cooling and the second mixed-refrigeration cycle for the liquefaction and sub-cooling of the hydrocarbon-rich stream to be liquefied, Scharacterised in that the first mixed-refrigerant cycle (1-12) is separated into a lower-boiling gas fraction (10) and a higher-boiling liquid fraction (2) and the two fractions 10) are supplied to the pre-cooling section (El) at different pressures.
2. Method according to claim 1, characterised in that the pre-cooling of the hydrocarbon-rich stream takes place in a spiral heat exchanger (El).
3. Method according to claim 1 or 2, whereby each mixed-refrigerant cycle includes at least one single-stage or multistage compressor driven by at least one gas turbine, starters that are used to support the gas turbines during normal operation being associated with the gas turbines, characterised in that the second mixed-refrigerant cycle (20-25) includes a cold-intake compressor (V2) having a pressure ratio of at least 10:1 and the first mixed-refrigerant cycle (1-12) is used at least partially for the intermediate cooling (El) of at least a part stream of the partially- compressed mixed-refrigerant stream (26, 29) of the second mixed- refrigerant cycle (20-25).
4. Method according to any one of the preceding claims, whereby higher- boiling hydrocarbons are separated in a separation unit after the pre- cooling of the hydrocarbon-rich stream to be liquefied, characterised in that a part stream of the mixed refrigerant of the second mixed-refrigerant cycle (20-30) is supplied to the separation unit for cooling purposes 11 0 cN and is then vaporised at a higher pressure than the remaining mixed- refrigerant stream of the second mixed-refrigerant cycle (20-30). \O \O 0 Method for the liquefaction of a hydrocarbon-rich stream, substantially as hereinbefore described with reference to the drawings.
6. The steps, features, compositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features. DATED this SIXTH day of JULY 2005 Linde Aktiengesellschaft AND Statoil ASA by DAVIES COLLISON CAVE SPatent Attorneys for the applicant(s) 5108
AU2005202956A 2004-07-06 2005-07-06 Method for the liquefaction of a hydrocarbon-rich stream Abandoned AU2005202956A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102004032710.6 2004-07-06
DE102004032710A DE102004032710A1 (en) 2004-07-06 2004-07-06 Method for liquefying a hydrocarbon-rich stream, especially a natural gas stream, comprises separating a first coolant mixture cycle into a low boiling fraction and a higher boiling fraction

Publications (1)

Publication Number Publication Date
AU2005202956A1 true AU2005202956A1 (en) 2006-02-02

Family

ID=35295142

Family Applications (1)

Application Number Title Priority Date Filing Date
AU2005202956A Abandoned AU2005202956A1 (en) 2004-07-06 2005-07-06 Method for the liquefaction of a hydrocarbon-rich stream

Country Status (5)

Country Link
CN (1) CN1719169A (en)
AU (1) AU2005202956A1 (en)
BR (1) BRPI0502741A (en)
DE (1) DE102004032710A1 (en)
NO (1) NO20053282L (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2007287506B2 (en) * 2006-08-24 2010-06-17 Shell Internationale Research Maatschappij B.V. Method for liquefying a hydrocarbon-rich stream
US9920987B2 (en) 2015-05-08 2018-03-20 Air Products And Chemicals, Inc. Mixing column for single mixed refrigerant (SMR) process

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011010633A1 (en) * 2011-02-08 2012-08-09 Linde Ag Method for cooling a one-component or multi-component stream
CN102538391B (en) * 2012-02-19 2013-09-04 中国石油集团工程设计有限责任公司 Multi-level single-component refrigeration natural gas liquefaction system and multi-level single-component refrigeration natural gas liquefaction method
CN102748918A (en) * 2012-07-03 2012-10-24 中国海洋石油总公司 Natural gas liquefying system by vurtue of double-stage mixed-refrigerant circulation
CN105473967B (en) * 2013-03-15 2018-06-26 查特能源化工公司 Mixed refrigerant systems and method
DE102016000393A1 (en) * 2015-10-01 2017-04-06 Linde Aktiengesellschaft Process for liquefying a hydrocarbon-rich fraction
US10323880B2 (en) * 2016-09-27 2019-06-18 Air Products And Chemicals, Inc. Mixed refrigerant cooling process and system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2007287506B2 (en) * 2006-08-24 2010-06-17 Shell Internationale Research Maatschappij B.V. Method for liquefying a hydrocarbon-rich stream
US9920987B2 (en) 2015-05-08 2018-03-20 Air Products And Chemicals, Inc. Mixing column for single mixed refrigerant (SMR) process

Also Published As

Publication number Publication date
BRPI0502741A (en) 2006-02-14
NO20053282L (en) 2006-01-09
DE102004032710A1 (en) 2006-02-09
NO20053282D0 (en) 2005-07-05
CN1719169A (en) 2006-01-11

Similar Documents

Publication Publication Date Title
US6378330B1 (en) Process for making pressurized liquefied natural gas from pressured natural gas using expansion cooling
AU2005202956A1 (en) Method for the liquefaction of a hydrocarbon-rich stream
JP6800977B2 (en) Precooling of natural gas by high pressure compression and expansion
JP5725856B2 (en) Natural gas liquefaction process
JP4938452B2 (en) Hybrid gas liquefaction cycle with multiple expanders
US6253574B1 (en) Method for liquefying a stream rich in hydrocarbons
JP4741468B2 (en) Integrated multi-loop cooling method for gas liquefaction
CA2090809C (en) Method for liquefying natural gas
AU2004221609B2 (en) Integrated multiple-loop refrigeration process for gas liquefaction
CA3056587C (en) Artic cascade method for natural gas liquefaction in a high-pressure cycle with pre-cooling by ethane and sub-cooling by nitrogen, and a plant for its implementation
CN101711335A (en) Method and system for producing LNG
EP2379967A2 (en) Method and system for producing liquified natural gas
AU2011321145B2 (en) Natural gas liquefaction process
US20090019888A1 (en) Method for liquefying a hydrocarbon-rich stream
AU2005303932B2 (en) Method for liquefying a hydrocarbon-rich flow
AU2006261281A1 (en) Method for liquefying a hydrocarbon-rich flow
AU2019202814A1 (en) Method and system for cooling a hydrocarbon stream using a gas phase refrigerant
AU2005224308B2 (en) Method for liquefying a hydrocarbon-rich flow
AU2005243086B2 (en) Method and device for liquefying a hydrocarbon-enriched flow
AU2008294046B2 (en) Natural gas liquefaction process
Liu et al. The High Pressure Expander Process Technology for LNG Applications
WO2023069139A1 (en) System and method to produce liquefied natural gas
Lee et al. The study on a new liquefaction cycle development for LNG plant

Legal Events

Date Code Title Description
MK4 Application lapsed section 142(2)(d) - no continuation fee paid for the application