WO2018091920A1 - Procédé et appareil de séparation d'hydrocarbures - Google Patents

Procédé et appareil de séparation d'hydrocarbures Download PDF

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Publication number
WO2018091920A1
WO2018091920A1 PCT/GB2017/053475 GB2017053475W WO2018091920A1 WO 2018091920 A1 WO2018091920 A1 WO 2018091920A1 GB 2017053475 W GB2017053475 W GB 2017053475W WO 2018091920 A1 WO2018091920 A1 WO 2018091920A1
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WO
WIPO (PCT)
Prior art keywords
stream
column
fractionation column
expanded
pressure
Prior art date
Application number
PCT/GB2017/053475
Other languages
English (en)
Inventor
Terence Ronald Tomlinson
Zak Richard LOFTUS
Original Assignee
Costain Oil, Gas & Process Limited
Finn, Adrian Joseph
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 Costain Oil, Gas & Process Limited, Finn, Adrian Joseph filed Critical Costain Oil, Gas & Process Limited
Priority to GB1908738.6A priority Critical patent/GB2571676A/en
Publication of WO2018091920A1 publication Critical patent/WO2018091920A1/fr

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    • 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
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
    • F25J3/0209—Natural gas or substitute natural gas
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
    • B01D3/322—Reboiler specifications
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/09—Purification; Separation; Use of additives by fractional condensation
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • C10L3/101—Removal of contaminants
    • 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
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
    • 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
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0238—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
    • 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
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0242—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 3 carbon atoms or more
    • 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
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/06—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation
    • F25J3/0605—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the feed stream
    • F25J3/061—Natural gas or substitute 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/04—Processes or apparatus using separation by rectification in a dual pressure main column 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/08—Processes or apparatus using separation by rectification in a triple pressure main column 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/40—Features relating to the provision of boil-up in the bottom of a column
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/70—Refluxing the column with a condensed part of the feed stream, i.e. fractionator top is stripped or self-rectified
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/76—Refluxing the column with condensed overhead gas being cycled in a quasi-closed loop refrigeration 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/78—Refluxing the column with a liquid stream originating from an upstream or downstream fractionator column
    • 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
    • F25J2205/04—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum in the feed line, i.e. upstream of the fractionation step
    • 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
    • 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
    • F25J2270/02—Internal refrigeration with liquid vaporising 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
    • F25J2270/04—Internal refrigeration with work-producing gas expansion loop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/12—External refrigeration with liquid vaporising 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
    • F25J2270/60—Closed external refrigeration cycle with single component refrigerant [SCR], e.g. C1-, C2- or C3-hydrocarbons

Definitions

  • This invention relates to a process, and apparatus for effecting such a process, for the cryogenic fractionation of gaseous hydrocarbon feeds to extract and recover the valuable heavier components thereof.
  • the invention is particularly concerned with a process for efficient recovery of ethane and heavier components from a natural gas feed.
  • the process is not limited to the recovery of paraffinic compounds such as ethane found in natural gas, but also, for example, to olefins such as ethylene often found in gases associated with petroleum refining or petrochemicals manufacture.
  • Processes to effect recovery of ethane and heavier components from natural gas typically utilise a combination of heat exchange, turbo-expansion, phase separation and fractionation steps.
  • the use of turbo-expansion of a gaseous stream produces work, which can be used to drive a compressor to supplement residual gas compression, and by removing energy from the expanded gas a low temperature expanded gas stream is produced.
  • EP 1 ,1 14,808 discloses a process for the separation of heavier hydrocarbons from a gaseous feed using a two fractionation column system, the configuration of which is shown in Figure 1.
  • the high-pressure gaseous feed (7 MPa) is partially condensed and separated, and the gaseous and liquid components are expanded to a lower pressure (3.5 MPa) prior to being fed into the first fractionation column.
  • Work expansion of the gaseous component from the separator prior to feeding into the first fractionation column can be used to drive a compressor.
  • a gaseous feed stream (2) is cooled and partially condensed in heat exchanger (4).
  • the partially condensed feed (6) is separated in a separator (8) to give a liquid stream (48) and a gaseous stream (10).
  • the gaseous stream (10) is work expanded in an expander (12) and the expanded stream (14) fed to a first fractionation column (16).
  • the liquid stream (48) is expanded through a valve (50), and fed to the first fractionation column (16).
  • the liquid stream (36) from the bottom of the first fractionation column (16) is subcooled in a heat exchanger (20), expanded through a valve (40), rewarmed in heat exchanger (20) and fed to a second fractionation column (54).
  • the gaseous stream (18) from the first fractionation column (16) is subcooled in a heat exchanger (20) and separated in second separator (24), from which the liquid stream (26) provides reflux to the first and second fractionation columns (16 and 54), and the gaseous stream (62) is used to provide cooling in the heat exchangers (20 and 4) then combined with a separated lights stream (56) from the second fractionation column (54).
  • EP1 137616 discloses a process for the separation of heavier hydrocarbons from a gaseous feed using a two fractionation column system.
  • the high-pressure gaseous feed (7 MPa) is partially condensed and separated, and the gaseous and liquid components are expanded to a lower pressure (2.5 MPa) prior to being fed into the first fractionation column.
  • a gaseous feed stream (2) is cooled and partially condensed in heat exchanger (4).
  • the partially condensed feed (6) is separated in a separator (8) to give a liquid stream (10) and a gaseous stream (14).
  • the gaseous stream (14) is work expanded in an expander (16) and the expanded stream (18) fed to a first fractionation column (24).
  • the liquid stream (10) is expanded through a valve (12), and the expanded stream (20) is combined with the expanded stream (18) from the gas fraction and fed to the first fractionation column (24).
  • the liquid stream (26) from the bottom of the first fractionation column (24) is expanded through a valve (28), rewarmed in two heat exchangers (32, 4) and fed to a second fractionation column (38).
  • the separated lights stream (48) from the second fractionation column (38) is cooled in a heat exchanger (32) and separated in second separator (52), from which the liquid stream (54) is pumped (56) and provides reflux to the second fractionation column (38) and another portion of the liquid stream (54) is pumped (59), cooled in a heat exchanger (32) and provides reflux to the first fractionation column.
  • the gaseous stream from the second separator (52) is warmed in two heat exchangers (32 and 4) and compressed in a compressor (76) to produce a compressed stream (78).
  • the gaseous stream (64) from the first fractionation column (24) is warmed in two heat exchangers (32, 4) and combined with the compressed stream (78) then further compressed in a compressor (82).
  • a process for the separation of a heavier hydrocarbon fraction from a high-pressure gaseous feed comprising a mixture of hydrocarbons which process comprises:
  • the first high-pressure partially condensed stream is fed to the first fractionation column at a pressure of no more than 7.5 MPa.
  • the first high-pressure partially condensed stream is fed to the first fractionation column at a pressure of at least 6.5 MPa.
  • the first high-pressure partially condensed stream is fed to the first fractionation column at a pressure of from 6.75 MPa to 7.25 MPa.
  • an increased proportion of the first partially condensed stream exits the first fractionation column in the gas phase as compared to a system comprising a separator (for example, as shown in Figure 1 ). Therefore, an increased proportion of the feed can be work expanded in order to recover an increased amount of energy from the let-down of the high-pressure feed in comparison to typical systems.
  • the work expansion of a stream will be understood to refer to the expansion of a stream whereby energy is recovered from the expansion.
  • the expansion may use a turbo expander.
  • the expander may be a single expander or a system of expanders (for example, a turbo expander system) and the actual quantity and configuration of expanders may vary.
  • Heavier hydrocarbons or a “heavier hydrocarbon fraction” as referred to herein, and as recovered as a bottoms stream from the second fractionation column, will be understood to mean a hydrocarbon fraction having an average molecular mass/boiling point higher than the separated lights fraction recovered from the top of the second fractionation column.
  • the heavier hydrocarbon fraction will comprise C 2 + hydrocarbons, for example ethane, ethylene and heavier molecules.
  • the heavier hydrocarbon fraction may include all hydrocarbons with the exception of methane.
  • expansion where energy recovery is not required will typically comprise expansion through a valve (e.g. a Joule-Thomson valve).
  • a valve e.g. a Joule-Thomson valve
  • expanders will generally have a bypass, which can be used to address bottlenecks in the system.
  • the first high-pressure partially condensed stream in part (a) is fed directly to the first fractionation column. In this way, the full line pressure of the feed stream may be maintained and utilised for energy recovery by work expansion.
  • the term "fed directly”, or “passed directly” in relation to a stream will be understood to mean that the stream will not be purposefully processed over the specified interval.
  • a stream fed directly from one part of the process to another will not be split or separated and will not be heated, cooled, expanded or compressed.
  • Minor or trivial operations on the stream will be understood not to be excluded by the term “directly”, as will changes to the stream which result from the passage of the stream inherently. For example, withdrawal of samples for analysis or minor temperature and/or pressure change (e.g. as a result of imperfect insulation of the stream) are not considered as processing of the stream for the purposes of feeding a stream "directly”.
  • cooling of the high-pressure gaseous feed in part (a) is provided, at least in part, by heat exchange with at least a portion the first expanded stream in part (c).
  • the overall refrigeration requirement may be reduced, lowering the total process energy requirement.
  • at least a portion of the first expanded stream in part (c) is fed directly to the second fractionation column.
  • at least a portion of the first expanded stream in part (c) is used to cool the high-pressure gaseous feed in heat exchange and then fed directly to the second fractionation column.
  • the first expanded stream may be split and/or integrated into the process in any other manner.
  • part (c) comprises expanding at least a substantial portion of said first liquid stream higher in heavier hydrocarbons to produce the first expanded stream.
  • part (c) comprises feeding at least a substantial portion of the first expanded stream to the second fractionation column.
  • a “substantial portion” as referred to herein will be understood to mean more than 50 % of the volumetric flow of a stream, preferably at least 60 %, more preferably 70 %, even more preferably 80 %, for example 90 % or 95 %. In particularly preferred embodiments, a "substantial portion" will comprise the entire volumetric flow of the stream in question.
  • part (d) comprises recovering process energy by work expanding at least a substantial portion of the first gaseous stream lower in heavier hydrocarbons to produce the expanded partially condensed stream.
  • part (d) comprises feeding at least a substantial portion of the expanded partially condensed stream to the second fractionation column.
  • At least a portion of the expanded partially condensed stream in part (d) is fed directly to the second fractionation column.
  • the expanded partially condensed stream may be split, integrated into other parts of the process (to provide cooling, for example) and/or fed into the second fractionation column at multiple positions.
  • the first and second fractionation columns may be any suitable columns.
  • the quantity of trays in each fractionation column may vary and can be provided in any suitable quantity and configuration.
  • the first fractionation column will operate at a pressure of greater than 6.0 MPa, and that the operating pressure will vary according to the pressure of the feed into the column as described previously.
  • the first fractionation column may comprise a condenser for providing reflux to an upper part of the column. It will be appreciated that any suitable condenser may be used. For example, a portion of the first gaseous stream may be partially condensed and separated, with the resultant liquid fraction being fed to an upper part of the first fractionation column. In other embodiments the first fractionation column will not comprise a condenser.
  • the second fractionation column will operate at a lower pressure than the first fractionation column.
  • the second fractionation column may operate at any suitable pressure, but in preferred embodiments, the second fractionation column will operate at a pressure of from 1.5 MPa to 5.0 MPa, preferably from 2.5 MPa to 4.5 MPa, more preferably from 3.0 to 4.0 MPa, for example 3.5 MPa.
  • Reboil may be provided to the first and second fractionation columns by any suitable means. By providing reboil to the first fractionation column, there will be an increase in the proportion of the first partially condensed stream exiting the first fractionation column in the gas phase. In this way, an increased amount of energy may be recovered during work expansion of the first gaseous stream.
  • reboil to the first fractionation column is provided, at least in part, by heat exchange with the high-pressure gaseous feed.
  • reboil may be provided by one or more side reboilers, wherein a stream is withdrawn from the side of the fractionation column, heated and partially vapourised, and fed back into the column. Integrating reboil streams in order to provide cooling to the gaseous feed leads to a reduction of the overall refrigeration requirement, lowering the total process energy requirement.
  • reboil may be provided to the first fractionation column by a standalone reboiler or by alternative heat integration.
  • reboil to the second fractionation column is provided, at least in part, by heat exchange with the high-pressure gaseous feed.
  • reboil may be provided by one or more side reboilers as described above.
  • reboil to the second fractionation column is provided, at least in part, by external heating, for example reboil to the second fractionation column may be provided, at least in part, by heating the bottoms stream in part (e) to produce a heated bottoms stream, and feeding at least a portion of said heated bottoms stream to a lower part of the second fractionation column.
  • reboil to the second fractionation column may be provided by both heat exchange and external heating as described previously, or may be provided by only one of these. Alternatively, reboil to the second fractionation column may be provided by any other standalone reboiler or alternative heat integration.
  • the separated lights stream is compressed to produce a high- pressure lights stream.
  • energy for the compression of the separated lights stream is provided, at least in part, by work expansion of the first gaseous stream in part (d).
  • the separated lights stream may be compressed using an expander brake coupled to an expander through which the first gaseous stream is expanded in part (d).
  • the separated lights stream will be compressed in one or more compressors in addition to or instead of the compression provided by work expansion of the first gaseous stream. Nonetheless, it will be appreciated that any suitable number and configuration of compressors may be incorporated for the compression of the separated lights stream.
  • the separated lights stream is cooled following compression.
  • compressor after cooling may comprise cooling against ambient air or cooling water.
  • reflux to the second fractionation column is provided by cooling, subcooling and expanding a recycle stream comprising a portion of the separated lights stream and feeding this subcooled and expanded recycle stream into the top of the second fractionation column.
  • the cooling and/or subcooling of the recycle stream may be provided by any suitable means, for example mechanical refrigeration or heat exchange with other process streams.
  • the cooling and/or subcooling of the recycle stream is provided, at least in part, by heat exchange with the separated lights stream.
  • the recycle stream will comprise at least a portion of the high-pressure lights stream.
  • the recycle stream may be split from the separated lights stream at any point prior to compression or from between individual compression stages at an intermediate pressure.
  • any suitable heat exchanger may be used.
  • any suitable number and configuration of heat exchangers may be used.
  • one or more heat exchangers in the system will be configured to process more than two streams.
  • all heat exchange with the high-pressure gaseous feed may take place in a single primary heat exchanger.
  • more than one heat exchanger may be used for providing heating or cooling to the high-pressure gaseous feed and/or any other streams.
  • cooling is provided to one or more streams by mechanical refrigeration.
  • the mechanical refrigeration may comprise any suitable system or configuration.
  • the mechanical refrigeration may comprise a single refrigerant at a single pressure stage, a single refrigerant at multiple pressure stages, a multicomponent refrigerant at a single pressure stage, a multicomponent refrigerant at multiple pressure stages, a combination thereof or any other mechanical refrigeration arrangement.
  • a refrigerant stream will provide cooling to process streams by heat exchange.
  • the refrigerant stream will be integrated into a heat exchanger, through which the high- pressure gaseous feed and optionally the recycle stream are passed.
  • composition of the heavier hydrocarbons recovered from the second fractionation column may be varied as necessary by varying the processing steps and conditions preceding the second fractionation column.
  • the process further comprises feeding at least a portion of the expanded partially condensed stream to a wash column and recovering from the wash column a wash column heavy stream higher in heavier hydrocarbons and a wash column lights stream lower in heavier hydrocarbons, and feeding at least a portion of the wash column heavy stream to the second fractionation column.
  • the heavier hydrocarbon fraction will comprise C 3+ hydrocarbons, for example propane, propylene and heavier molecules.
  • the heavier hydrocarbon fraction may comprise any hydrocarbons with the exception of methane and ethane.
  • the expanded partially condensed stream contains a larger proportion of the lighter hydrocarbon fraction from the feed stream than where a separator is used in place of the first fractionation column.
  • a lighter hydrocarbon fraction such as a Ci or C 2 fraction may be removed from the feed prior to the second fractionation column, which may lead to increased efficiency of separation.
  • wash column referred to herein will be a fractionation column.
  • the wash column may be any suitable column.
  • the quantity of trays in the wash column may vary and can be provided in any suitable quantity and configuration.
  • the wash column may operate at any suitable pressure, but in preferred embodiments, the wash column will operate at a pressure of from 1.5 MPa to 5.5 MPa, preferably from 2.5 MPa to 5.0 MPa, more preferably from 3.5 to 4.5 MPa, for example 4.0 MPa.
  • the second fractionation column will typically operate at a lower pressure than the wash column, and may be any suitable pressure. In preferred embodiments where the wash column is present, the second fractionation column will operate at a pressure of from 1.0 MPa to 5.0 MPa, preferably from 1.5 MPa to 4.0 MPa, more preferably from 2.0 to 3.0 MPa, for example 2.5 MPa.
  • the process comprises feeding at least a substantial portion of the expanded partially condensed stream to the wash column.
  • the process comprises feeding at least a portion of the first expanded stream to the wash column.
  • at least a portion of the first expanded stream is fed to the wash column at a lower position than the expanded partially condensed stream is fed to the wash column.
  • the expanded partially condensed stream contains a greater proportion of the feed material.
  • the amount of lighter hydrocarbons, for example C 1 and C 2 hydrocarbons, dissolved in the wash column liquids may be reduced. This may lead to a reduction in the lighter hydrocarbons carried to the second fractionation column, increasing separation efficiency. Nonetheless, it will be understood that at least a portion of the first expanded stream may partially or substantially bypass the wash column and be fed to the second fractionation column.
  • the process comprises feeding at least a substantial portion of the wash column heavy stream to the second fractionation column.
  • At least a portion of the wash column heavy stream is expanded before being fed to the second fractionation column.
  • the expanded wash column heavy stream is heated before being fed to the second fractionation column. It will be appreciated that any suitable heating may be used.
  • cooling of the high-pressure gaseous feed in part (a) is provided, at least in part, by heat exchange with the expanded wash column heavy stream.
  • cooling of the high-pressure gaseous feed in part (a) is provided, at least in part, by heat exchange with the wash column lights stream. It will be appreciated that by integrating the cooling of the gaseous feed stream with heating the expanded wash column heavy stream or wash column lights stream, or other process streams, the overall refrigeration requirement may be reduced, lowering the total process energy requirement.
  • At least a portion of the separated lights stream is cooled to produce a partially condensed separated lights stream which is fed to a separator to produce a second separated lights stream and a separated heavy stream, wherein at least a portion of the separated heavy stream is fed to the an upper part of the second fractionation column to provide reflux to the second fractionation column.
  • at least a portion of the separated heavy stream is subcooled and fed to an upper part of the wash column to provide reflux to the wash column.
  • reflux to the second fractionation column or wash column may be provided from other sources and may comprise more than one reflux stream.
  • the separated heavy stream may be used to provide reflux separately to either the second fractionation column or wash column, or to both.
  • reflux to the wash column is provided by cooling, subcooling and expanding a recycle stream, the recycle stream comprising at least a portion of the separated lights stream and/or the wash column lights stream, and feeding the subcooled and expanded recycle stream into an upper part of the wash column.
  • cooling of the separated lights stream is provided, at least in part, by heat exchange with the wash column lights stream and/or the wash column heavy stream and/or the second separated lights stream.
  • subcooling of the separated heavy stream is provided, at least in part, by heat exchange with the wash column lights stream and/or the wash column heavy stream and/or the second separated lights stream.
  • cooling of the high-pressure gaseous feed in part (a) is provided, at least in part, by heat exchange with the second separated lights stream.
  • the light hydrocarbons recovered from the process will typically be compressed to a suitable pressure for export. Compression of the light hydrocarbons may be performed in any suitable way with any suitable compressor configuration. In preferred embodiments, at least a portion of the wash column lights stream is combined with the second separated lights stream and compressed to produce a high pressure lights stream.
  • energy for the compression of process streams may be provided, at least in part, by work expansion of the first gaseous stream in part (d).
  • the wash column lights stream, the second separated lights stream or a combination thereof may suitably be compressed using an expander brake coupled to an expander through which the first gaseous stream is expanded in part (d).
  • the wash column heavy stream may suitably be fed to the second fractionation column substantially without combining with other process streams. Nonetheless, in some embodiments at least a portion of the first expanded stream is combined with the wash column heavy stream before being fed to the second fractionation column.
  • first expanded stream may be fed directly to the wash column, or may directly bypass the wash column and be fed to the second fractionation column. Nonetheless, in some preferred embodiments, at least a portion of the first expanded stream is fed to a second separator to produce a light intermediate stream and a heavy intermediate stream, wherein the light intermediate stream is fed to the wash column and the heavy intermediate stream is combined with the wash column heavy stream and/or fed to the second fractionation column.
  • the heavy and/or light intermediate streams may preferably be cooled in heat exchange with the wash column lights stream and/or the wash column heavy stream and/or the second separated lights stream.
  • a first expander configured to expand at least a portion of the first liquid stream higher in heavier hydrocarbons to produce a first expanded stream, means for feeding at least a portion of said first expanded stream to the second fractionation column;
  • a second expander configured to recover process energy by work expanding at least a portion of the first gaseous stream lower in heavier hydrocarbons to produce an expanded partially condensed stream, and means for feeding at least a portion of said expanded partially condensed stream to the second fractionation column;
  • the apparatus further comprises a wash column and means for feeding at least a portion of the expanded partially condensed stream to the wash column; means for recovering from the wash column a wash column heavy stream higher in heavier hydrocarbons and a wash column lights stream lower in heavier hydrocarbons; and means for feeding at least a portion of the wash column heavy stream to the second fractionation column.
  • wash column and other elements of the apparatus or configurations of the apparatus comprising a wash column may be as described previously herein.
  • a process for the separation of a heavier hydrocarbon fraction from a high-pressure gaseous feed comprising a mixture of hydrocarbons which process comprises:
  • an apparatus for the separation of a heavier hydrocarbon fraction from a high-pressure gaseous feed comprising a mixture of hydrocarbons which apparatus comprises;
  • a first expander configured to expand at least a portion of the first liquid stream higher in heavier hydrocarbons to produce a first expanded stream, means for feeding at least a portion of said first expanded stream to the second fractionation column;
  • a second expander configured to recover process energy by work expanding at least a portion of the first gaseous stream lower in heavier hydrocarbons to produce an expanded partially condensed stream, and means for feeding at least a portion of said expanded partially condensed stream to the wash column;
  • (f-ii) means for recovering from the wash column a wash column heavy stream higher in heavier hydrocarbons and a wash column lights stream lower in heavier hydrocarbons;
  • (f-iii) means for feeding at least a portion of the wash column heavy stream to the second fractionation column;
  • (h) means for recovering from said second fractionation column said heavier hydrocarbon fraction as a bottoms stream.
  • first and second fractionation columns, the wash column, the expanders and other elements of the apparatus or configurations of the apparatus may be as described previously herein.
  • Figure 1 shows a prior art process for the separation of heavier hydrocarbons from a gaseous hydrocarbon feed comprising a two column arrangement.
  • Figure 2 shows an embodiment of the present invention, wherein a high-pressure gaseous feed is fed directly into a first fractionation column and process energy is recovered by work expansion of the gaseous fraction therefrom.
  • Figure 3 shows an embodiment of the present invention comprising a wash column, wherein a high-pressure gaseous feed is fed directly into a first fractionation column and process energy is recovered by work expansion of the gaseous fraction therefrom.
  • Figure 4 shows another embodiment of the present invention comprising a wash column, wherein a high-pressure gaseous feed is fed directly into a first fractionation column and process energy is recovered by work expansion of the gaseous fraction therefrom.
  • Figure 5 shows a different prior art process for the separation of heavier hydrocarbons from a gaseous hydrocarbon feed comprising a two column arrangement.
  • a high-pressure gaseous feed (202) at a pressure of 7.0 MPa is cooled and partially condensed in the primary heat exchanger (204) to produce a first high-pressure partially condensed stream (206).
  • the first high-pressure partially condensed stream (206) is fed to the upper portion of a first fractionation column (208) at a pressure of 7.0 MPa.
  • a first liquid stream (218) higher in heavier hydrocarbons and a first gaseous stream (210) lower in heavier hydrocarbons are withdrawn from the first fractionation column (208).
  • the first liquid stream (218) is expanded across a valve (292) to produce a first expanded stream, which may also be partially condensed.
  • a portion of the first expanded stream (222) may be fed directly to a second fractionation column (216).
  • a portion (224) may also be fed to the primary heat exchanger (204) where this stream is partially vaporised to provide cooling to the high-pressure gaseous feed, producing partially vaporised stream (226) which is then fed to the second fractionation column (216).
  • the split between streams 222 and 224 may include any suitable variation in flow ratios, including total flow to either stream.
  • the first gaseous stream (210) is work expanded in a turbo expander (212) to form an expanded partially condensed stream (214), which is fed to an upper part of the second fractionation column (216).
  • a liquid stream (284) is withdrawn from a tray part way up the first fractionation column (208) and fed to the primary heat exchanger (204), where it is partially vaporised and fed back to the first fractionation column (208) as a partially condensed stream (286) in order to provide reboil.
  • Refrigeration for cooling the high-pressure gaseous feed (202) or to any other part of the process may be supplemented by mechanical refrigeration.
  • a cold liquid propane refrigerant stream (288) is evaporated in the primary heat exchanger (204) to a produce refrigerant vapour stream (290).
  • a separated lights stream (230) is withdrawn from the top of the second fractionation column.
  • the separated lights stream is heated in a secondary heat exchanger (220) and in the primary heat exchanger (204), where cooling is provided to the high-pressure gaseous feed.
  • the warmed lights stream (234) is compressed in an expander brake (236) and cooled to give a gas stream (242), which is compressed in a compressor (244) and cooled to give a gas product stream (254).
  • the compressor after cooling is typically against ambient air or cooling water.
  • a recycle stream (252) is split from the cooled and compressed lights stream (250) and fed to the primary heat exchanger (204) where it is cooled and partially condensed.
  • This cooled and partially condensed recycle stream (256) is then fed to the secondary heat exchanger (220) where the stream is subcooled and fully condensed.
  • the subcooled and condensed recycle stream (258) is then expanded across a valve (260) to the same pressure as the second fractionation column (216) and the subcooled and expanded recycle stream (262) is fed to the top of the second fractionation column (216) as reflux.
  • a bottoms stream (276) comprising the heavier hydrocarbon fraction (C 2 +) is drawn from the bottom of the second fractionation column (216).
  • the bottoms stream (276) is heated in a heater (278) and a portion of the heated bottoms stream (280) is fed to a lower part of the second fractionation column (216) to provide reboil.
  • a liquid product stream (282), comprising the remainder of the heated bottoms stream, is removed for further processing.
  • Reboil to the second fractionation column is also provided by three liquid streams (264, 268, 272) drawn from trays part way up the second fractionation column (216), fed to the primary heat exchanger (204) where they are partially vaporised, and then fed back to the second fractionation column (216) as partially vaporised streams (266, 270, 274). It will be appreciated that, while in this embodiment reboil is provided by both the heated bottoms stream (280) and reboil streams (264, 268, 272), reboil could be provided by only one of these systems, or by an alternative system.
  • a high-pressure gaseous feed (302) at a pressure of 7.0 MPa is cooled and partially condensed in the primary heat exchanger (304) to produce a first high-pressure partially condensed stream (306).
  • the first high-pressure partially condensed stream (306) is fed to the upper portion of a first fractionation column (308) at a pressure of 7.0 MPa.
  • a first liquid stream (310) higher in heavier hydrocarbons and a first gaseous stream (314) lower in heavier hydrocarbons are withdrawn from the first fractionation column (308).
  • the first liquid stream (310) is expanded across a valve (312) to produce a first expanded stream (320), which may also be partially condensed.
  • the first expanded stream (320) is fed to a lower part of a wash column (324).
  • the first gaseous stream (314) is work expanded in a turbo expander (316) to form an expanded partially condensed stream (318), which is fed to a higher part of the wash column (324) than the first expanded stream.
  • a liquid stream (390) is withdrawn from a tray part way up the first fractionation column (308) and fed to the primary heat exchanger (304), where it is partially vaporised and fed back to the first fractionation column (308) as a partially condensed stream (392) in order to provide reboil.
  • Refrigeration for cooling the high-pressure gaseous feed (302) or to any other part of the process may be supplemented by mechanical refrigeration.
  • a cold liquid propane refrigerant stream (394) is evaporated in the primary heat exchanger (304) to a produce refrigerant vapour stream (396).
  • a wash column heavy stream (326) is withdrawn from the bottom of the wash column (324).
  • the wash column heavy stream is expanded across a valve (328) and is heated in a secondary heat exchanger (332), and in the primary heat exchanger (304) before being fed to a second fractionation column (338).
  • a wash column lights stream (364) is withdrawn from the top of the wash column (324).
  • the wash column lights stream (364) is heated in the secondary heat exchanger (332), and in the primary heat exchanger (304) before being combined with a compressed lights stream (378) to give a combined lights stream (380).
  • the combined lights stream (380) is compressed in a compressor (382) and cooled in a cooler (386) to give a gas product stream (388).
  • the compressor after cooling is typically against ambient air or cooling water.
  • a separated lights stream (348) is withdrawn from the top of the second fractionation column (338).
  • the separated lights stream (348) is cooled in the secondary heat exchanger (332) and fed to a separator (352), from which a second separated lights stream (370) and a separated heavy stream (354) are withdrawn.
  • the second separated lights stream (370) is warmed in the secondary heat exchanger (332) and the primary heat exchanger (304), then compressed in a first stage compressor (376) and combined with the heated wash column lights stream (368) to produce the combined lights stream (380).
  • the separated heavy stream (354) is split and a first portion is pumped (356) to provide a reflux stream (358) to the top of the second fractionation column (338).
  • a second portion of the separated heavy stream (354) is pumped (359) and subcooled in the secondary heat exchanger (332) to provide a subcooled reflux stream (362) to the top of the wash column (324).
  • a bottoms stream (340) comprising the heavier hydrocarbon fraction (C 3 +) is drawn from the bottom of the second fractionation column (338).
  • the bottoms stream (340) is heated in a heater (342) and a portion of the heated bottoms stream (346) is fed to a lower part of the second fractionation column (338) to provide reboil.
  • a liquid product stream (344), comprising the remainder of the heated bottoms stream, is removed for further processing.
  • Figure 4 shows an embodiment arranged substantially as for Figure 3, with the exception that the first expanded stream (320) is fed to a second separator (400) to produce a light intermediate stream (402) and a heavy intermediate stream (404).
  • the light intermediate stream (402) and heavy intermediate stream (404) are cooled in the primary heat exchanger (304) and the secondary heat exchanger (332).
  • the cooled light intermediate stream (410) is fed to a lower part of the wash column than the expanded partially condensed stream (318).
  • the cooled heavy intermediate stream (412) is combined with the expanded wash column heavy stream to produce a combined heavy stream (430).
  • Table 3 shows Material Balance data for operation of the system shown in Figure 3 and Table 4 shows Material Balance data for operation of the system shown in Figure 4.
  • Table 2 shows Material Balance data for operation of the prior art system shown in Figure 1 and Table 5 shows Material Balance data for operation of the prior art system shown in Figure 5.
  • Tables 1 and 2 shows that the embodiment of the process of the present invention shown in Figure 2 has a total power input of 12,490 kW, for an ethane recovery of 95 %, as compared to 13,318 kW for the prior art system shown in Figure 1.
  • Tables 3, 4 and 5 shows that the embodiments of the process of the present invention shown in Figures 3 and 4 have respective total power inputs of 8,837 kW and 8,671 kW, for a propane recovery of 99.6%, as compared to 1 1 ,492 kW, for a propane recovery of 96.7%, for the system shown in Figure 5.
  • Table 5 shows that in the system of Figure 5, only 78 % of the mass flow of the high-pressure feed is routed to the work expander inlet. Conversely, in the system of the present invention, as shown in the embodiments of Figures 3 and 4, 81 % of the mass flow of the high-pressure feed is routed to the work expander inlet.

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Abstract

La présente invention concerne un procédé, et un appareil pour mettre en oeuvre un tel procédé, pour le fractionnement cryogénique de charges d'hydrocarbures gazeux afin d'extraire et de récupérer les composants précieux les plus lourds de ceux-ci. L'invention concerne en particulier un procédé de récupération efficace d'éthane et de composants plus lourds à partir d'une alimentation en gaz naturel.
PCT/GB2017/053475 2016-11-18 2017-11-17 Procédé et appareil de séparation d'hydrocarbures WO2018091920A1 (fr)

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Citations (3)

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US20050229634A1 (en) * 2004-04-15 2005-10-20 Abb Lummus Global Inc. Hydrocarbon gas processing for rich gas streams
WO2009076357A1 (fr) * 2007-12-10 2009-06-18 Conocophillps Company Système optimisé d'élimination de métaux lourds dans une installation de gaz naturel liquéfié (gnl)
US20110067442A1 (en) * 2009-09-21 2011-03-24 Ortloff Engineers, Ltd. Hydrocarbon Gas Processing

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US4545861A (en) * 1981-07-14 1985-10-08 Exxon Research And Engineering Co. Fractionation system
AR007346A1 (es) * 1996-06-05 1999-10-27 Shell Int Research Un metodo para separar dioxido de carbono, etano y componentes mas pesados de una corriente de gas natural a alta presion
GB9826999D0 (en) * 1998-12-08 1999-02-03 Costain Oil Gas & Process Limi Low temperature separation of hydrocarbon gas
GB0000327D0 (en) * 2000-01-07 2000-03-01 Costain Oil Gas & Process Limi Hydrocarbon separation process and apparatus
GB2456691B (en) * 2009-03-25 2010-08-11 Costain Oil Gas & Process Ltd Process and apparatus for separation of hydrocarbons and nitrogen
US9021832B2 (en) * 2010-01-14 2015-05-05 Ortloff Engineers, Ltd. Hydrocarbon gas processing

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Publication number Priority date Publication date Assignee Title
US20050229634A1 (en) * 2004-04-15 2005-10-20 Abb Lummus Global Inc. Hydrocarbon gas processing for rich gas streams
WO2009076357A1 (fr) * 2007-12-10 2009-06-18 Conocophillps Company Système optimisé d'élimination de métaux lourds dans une installation de gaz naturel liquéfié (gnl)
US20110067442A1 (en) * 2009-09-21 2011-03-24 Ortloff Engineers, Ltd. Hydrocarbon Gas Processing

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