CA1184210A - Cryogenic gas plant - Google Patents
Cryogenic gas plantInfo
- Publication number
- CA1184210A CA1184210A CA000416076A CA416076A CA1184210A CA 1184210 A CA1184210 A CA 1184210A CA 000416076 A CA000416076 A CA 000416076A CA 416076 A CA416076 A CA 416076A CA 1184210 A CA1184210 A CA 1184210A
- Authority
- CA
- Canada
- Prior art keywords
- stream
- column
- reflux
- feedstream
- ethane
- 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.)
- Expired
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
- 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
- F25J3/0204—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
-
- 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
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/02—Processes or apparatus using separation by rectification in a single 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
- F25J2200/30—Processes or apparatus using separation by rectification using a side column in a single pressure 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
- F25J2200/76—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
- F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
- F25J2230/08—Cold compressor, i.e. suction of the gas at cryogenic temperature and generally without afterstage-cooler
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
- F25J2230/60—Processes or apparatus involving steps for increasing the pressure of gaseous process streams the fluid being hydrocarbons or a mixture of hydrocarbons
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
- F25J2290/40—Vertical layout or arrangement of cold equipments within in the cold box, e.g. columns, condensers, heat exchangers etc.
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)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A B S T R A C T
CRYOGENIC GAS PLANT
A process for separating substantially all of the C3 and heavier components and a major portion of the C2 component from a natural gas stream using a cryogenic process. The process uses a rectifying column 12 in combination with a demethanizing column 22 to separate the C2 and heavier components with a reflux for the rectifying column, which reflux 13 is supplied by compressing a small portion of the overhead stream 11 and condensing it via heat exchange with the overhead stream.
CRYOGENIC GAS PLANT
A process for separating substantially all of the C3 and heavier components and a major portion of the C2 component from a natural gas stream using a cryogenic process. The process uses a rectifying column 12 in combination with a demethanizing column 22 to separate the C2 and heavier components with a reflux for the rectifying column, which reflux 13 is supplied by compressing a small portion of the overhead stream 11 and condensing it via heat exchange with the overhead stream.
Description
~ 3'~
CRYOGENIC GAS PLANT
The present invention relates to a cryogenic gas plant and particularly to a gas plant which is designed to separate natural gas liquids (NGL), which contain ethane and higher boiling hydro-carbons from a natural gas feedstream.
The evolution of cryogenic gas plants is reviewed in a paper presented at the 1977 Gas Processing Association Convention entitled "Evolution in Design" by R.L~ McKee. This paper describes the use of turbo-expanders to increase the thermodynamic efficiency of a gas plant and thus improve its overall economics. A similar type of cryogenic system for recovering ethane and higher boiling hydrocarbons from a natural gas stream is described in U.S. Patent Specification No. 3,292,380. ~ more recent description of cryogenic gas processin~ plants appears in the July 14, 1980 edition of the "Oil and Gas Journal" at page 76 et. seq. All of these references describe the use of a turbo-expander for supplying the feedstock to a demethanizing column where the methane is separated from the ethane and the higher boiling hydrocarbons.
While these systems have been satisfactory, they do nGt recover all the ethane and higher boiling point liquids. The ethanP
and hlgher boiling point liquids are used as chemical feedstocks which have more value in today's markets as chemical feedstocks than as natural gas. The lack of complete recovery of the ethane partially is due to the relativ2 volatility of methane to eehane and to the fact that a considerable amount of the ethane is ~5 contained as a vapour in the methane when it enters the demethanizing column. The portion of the ethane contained as vapour remains in the gas phase and is discharged from the top of the column as pipeline gas.
A further problem arises when attempts are made to operate plants near their capacity or beyond. When operating plants at or above their capacity, flooding of the demethanizing column with lt~
liquid occurs. When this occurs, additional ethane and higher boiling point liquids are lost to the natural gas stream instead of being condensed and removed as liquid from the bottom of the column.
The object of the present invention is to solve the above problems.
The process for separating ethane and heavier components from a natural gas feedstream utilizing a cryogenic plant having A co:ld feedstream thereto comprises according to the invention introducing the feedstream into a rectifier column to recover ethane from the feedstream and ~ithdra~ing methane as a overhead stream, passlng a portlon of the overhead stream back to the top of said rectifier column as a reflux stream, the pressure of said reflux stream being increased above the pressure of said overhead stream;
introducing the boetom stream of said rectifier column as a feed to a demethanizer column; and returning the top stream of said demethanizer colu~n as a bottom feed to said rectifier column.
According to the invention the aforementioned problems are solved by placing a rectifying column ahead of the demethanizing column. The rectifying column is provided with a reflux system while the liquefied bottom stream from the rectifying column is used as a feed for the demethanizing column. The combination of the rectifying column and the demethanizing column can provide essentially 100% recovery of the ethane and higher boiling point liquids from a natural gas stream. The reflux of the rectifying column uses a small portion of the overhead stream from the rectifying column, about 10% to 17%. The reflux stream is produced by a compressor and a condenser which is cooled by the overhe2d stream from the rectifying column. The use of a liquid reflux stream increases recovery of NGL9 the ethane and higher boiling point liquids, while the use of the demethanizing column insures that sufficient methane will be removed from the NGL product~ It is to be noted that the rectifying column also can be placed on top of the demethani~ing stripper column, both being one common vessel, in order to reduce equipment costs and complexity, including elimination of the need to pump liquid from the bottom of the rectifying column to the top of the demethanizing co umn.
The present invention will be more easily understood from the following detailed desc~iption of a preferred embodiment when taken in con~unction with the attached drawing showing schematically a gas processing system constructed accordlng to the present lnvention, Referring to the attached drawlng, there ls shown a rectlfying column 12 that has been added ahead of a demethanizlng stripper column 22. In known gas plants the demethanizing column is supplied with a partially liquefied feedstream 10 from a turbo-expander not shown in the drawing. Such a known plant wlthout a rectifying column will recover approximately 76% of the ethane while the present invention provides a plant enabling the recovery of approximately 93~D of the ethane and essentially all of the higher boiling liquids.
Apart from a turbo-expander for supplying the feedstream 10 other systems could be used to supply the cold vapour liquid feedstream. For example, r~frigeration systems could be used to supply the feedstream. The feedstream should have a temperature in the range of -73 C to -115 C and a pres~ure in the range of 1720 kPa to 3100 kPa. In an existing plane the feedstream from the turbo-expander has a pressure of 2654 kPa and a temperature o~ -93 C.
Rectifying column 12 is supplied with the feedstream 10, formerly supplied in the demethanizing column 22, having a temperature of approximately minus 94C and comprising essentially methane gas and higher boiling point liquid hydrocarbons. Th ethane and higher boiling point liquids are stripped from the feedstream and removed from the bottom of the rectifying column while the methane is withdrawn as an overhead stream 11.
A small portion of the overhead stream of the column 12 is taken off as a reflux stream 13 and compressed by compressor 14.
As explained above, the reflux should comprise a small portion of the total flow, approximately 10% to 17%, of the overhead stream. The compressed reflux stream is passed through a condenser 15 where :It is condensed by the overhead stream 11 with the flow of the overhead stream through the condenser being controlled by a bypass valve 17. A valve 16 controls the condensing pressure and the flow of reflux to the rectifying column 12. The liquid reflux supplied to the rectifying column efects recovery of most of the ethane and essentially all the higher boiling point hydrocarbon from the feedstream 10. The liquid bottom stream 20, including a substantial quantity of methane, is pumpe.d to the demethanizing column 22 by a pump 21.
The top stream 23 from the demethanizing column, consisting of methane and a smaller amount,of ethane and higher boiling liquids, flows into the bottom part of the rectifying column 12.
The rectifying column 12 and the demethanizing column 22 are reboiled by warmer portions of the gas stream upstream of the ~urbo-expander, not sho~m in the drawing.
NGL product is withdrawn from the bottom of demethanizing column 22 through a line 30 and supplied by pump 31 as a chemical feedstock to other processing units not shown. The bottom reboiler 32 and side reboilers 24 and 25 ensure that sufficient methane is removed from the NGL product.
From the above description, it is seen that only a small portion of the overhead stream of the rectifying column is used as reflux. Further, a compressor can be used to compress this fluid to higher pressure which permits its condensation to a liquid using the overhead stream from the column as the cooling medium. Thus3 a liquid reflux is obtalned with minimum expenditure of energy in contrast to the use of turbo-expanders in - ~ s -prior systems. The use of a liquid reflux in the rectifying column ensures that more than 90% of the ethane and essentially 100% of the hlgher boiling point liquids are removed from the feedstream 10. By removing some of the methane from the liquid in the rectifying column, the load on the demethanizing column 22 is reduced with the net result that the ehroughput of the plant can be increased if one so desires.
CRYOGENIC GAS PLANT
The present invention relates to a cryogenic gas plant and particularly to a gas plant which is designed to separate natural gas liquids (NGL), which contain ethane and higher boiling hydro-carbons from a natural gas feedstream.
The evolution of cryogenic gas plants is reviewed in a paper presented at the 1977 Gas Processing Association Convention entitled "Evolution in Design" by R.L~ McKee. This paper describes the use of turbo-expanders to increase the thermodynamic efficiency of a gas plant and thus improve its overall economics. A similar type of cryogenic system for recovering ethane and higher boiling hydrocarbons from a natural gas stream is described in U.S. Patent Specification No. 3,292,380. ~ more recent description of cryogenic gas processin~ plants appears in the July 14, 1980 edition of the "Oil and Gas Journal" at page 76 et. seq. All of these references describe the use of a turbo-expander for supplying the feedstock to a demethanizing column where the methane is separated from the ethane and the higher boiling hydrocarbons.
While these systems have been satisfactory, they do nGt recover all the ethane and higher boiling point liquids. The ethanP
and hlgher boiling point liquids are used as chemical feedstocks which have more value in today's markets as chemical feedstocks than as natural gas. The lack of complete recovery of the ethane partially is due to the relativ2 volatility of methane to eehane and to the fact that a considerable amount of the ethane is ~5 contained as a vapour in the methane when it enters the demethanizing column. The portion of the ethane contained as vapour remains in the gas phase and is discharged from the top of the column as pipeline gas.
A further problem arises when attempts are made to operate plants near their capacity or beyond. When operating plants at or above their capacity, flooding of the demethanizing column with lt~
liquid occurs. When this occurs, additional ethane and higher boiling point liquids are lost to the natural gas stream instead of being condensed and removed as liquid from the bottom of the column.
The object of the present invention is to solve the above problems.
The process for separating ethane and heavier components from a natural gas feedstream utilizing a cryogenic plant having A co:ld feedstream thereto comprises according to the invention introducing the feedstream into a rectifier column to recover ethane from the feedstream and ~ithdra~ing methane as a overhead stream, passlng a portlon of the overhead stream back to the top of said rectifier column as a reflux stream, the pressure of said reflux stream being increased above the pressure of said overhead stream;
introducing the boetom stream of said rectifier column as a feed to a demethanizer column; and returning the top stream of said demethanizer colu~n as a bottom feed to said rectifier column.
According to the invention the aforementioned problems are solved by placing a rectifying column ahead of the demethanizing column. The rectifying column is provided with a reflux system while the liquefied bottom stream from the rectifying column is used as a feed for the demethanizing column. The combination of the rectifying column and the demethanizing column can provide essentially 100% recovery of the ethane and higher boiling point liquids from a natural gas stream. The reflux of the rectifying column uses a small portion of the overhead stream from the rectifying column, about 10% to 17%. The reflux stream is produced by a compressor and a condenser which is cooled by the overhe2d stream from the rectifying column. The use of a liquid reflux stream increases recovery of NGL9 the ethane and higher boiling point liquids, while the use of the demethanizing column insures that sufficient methane will be removed from the NGL product~ It is to be noted that the rectifying column also can be placed on top of the demethani~ing stripper column, both being one common vessel, in order to reduce equipment costs and complexity, including elimination of the need to pump liquid from the bottom of the rectifying column to the top of the demethanizing co umn.
The present invention will be more easily understood from the following detailed desc~iption of a preferred embodiment when taken in con~unction with the attached drawing showing schematically a gas processing system constructed accordlng to the present lnvention, Referring to the attached drawlng, there ls shown a rectlfying column 12 that has been added ahead of a demethanizlng stripper column 22. In known gas plants the demethanizing column is supplied with a partially liquefied feedstream 10 from a turbo-expander not shown in the drawing. Such a known plant wlthout a rectifying column will recover approximately 76% of the ethane while the present invention provides a plant enabling the recovery of approximately 93~D of the ethane and essentially all of the higher boiling liquids.
Apart from a turbo-expander for supplying the feedstream 10 other systems could be used to supply the cold vapour liquid feedstream. For example, r~frigeration systems could be used to supply the feedstream. The feedstream should have a temperature in the range of -73 C to -115 C and a pres~ure in the range of 1720 kPa to 3100 kPa. In an existing plane the feedstream from the turbo-expander has a pressure of 2654 kPa and a temperature o~ -93 C.
Rectifying column 12 is supplied with the feedstream 10, formerly supplied in the demethanizing column 22, having a temperature of approximately minus 94C and comprising essentially methane gas and higher boiling point liquid hydrocarbons. Th ethane and higher boiling point liquids are stripped from the feedstream and removed from the bottom of the rectifying column while the methane is withdrawn as an overhead stream 11.
A small portion of the overhead stream of the column 12 is taken off as a reflux stream 13 and compressed by compressor 14.
As explained above, the reflux should comprise a small portion of the total flow, approximately 10% to 17%, of the overhead stream. The compressed reflux stream is passed through a condenser 15 where :It is condensed by the overhead stream 11 with the flow of the overhead stream through the condenser being controlled by a bypass valve 17. A valve 16 controls the condensing pressure and the flow of reflux to the rectifying column 12. The liquid reflux supplied to the rectifying column efects recovery of most of the ethane and essentially all the higher boiling point hydrocarbon from the feedstream 10. The liquid bottom stream 20, including a substantial quantity of methane, is pumpe.d to the demethanizing column 22 by a pump 21.
The top stream 23 from the demethanizing column, consisting of methane and a smaller amount,of ethane and higher boiling liquids, flows into the bottom part of the rectifying column 12.
The rectifying column 12 and the demethanizing column 22 are reboiled by warmer portions of the gas stream upstream of the ~urbo-expander, not sho~m in the drawing.
NGL product is withdrawn from the bottom of demethanizing column 22 through a line 30 and supplied by pump 31 as a chemical feedstock to other processing units not shown. The bottom reboiler 32 and side reboilers 24 and 25 ensure that sufficient methane is removed from the NGL product.
From the above description, it is seen that only a small portion of the overhead stream of the rectifying column is used as reflux. Further, a compressor can be used to compress this fluid to higher pressure which permits its condensation to a liquid using the overhead stream from the column as the cooling medium. Thus3 a liquid reflux is obtalned with minimum expenditure of energy in contrast to the use of turbo-expanders in - ~ s -prior systems. The use of a liquid reflux in the rectifying column ensures that more than 90% of the ethane and essentially 100% of the hlgher boiling point liquids are removed from the feedstream 10. By removing some of the methane from the liquid in the rectifying column, the load on the demethanizing column 22 is reduced with the net result that the ehroughput of the plant can be increased if one so desires.
Claims (6)
1. A process for separating ethane and heavier components from a natural gas feed stream utilizing a cryogenic plant having a cold feedstream, said process comprising:
introducing the feedstream into a rectifier column to recover ethane from the feedstream and withdrawing methane as a overhead stream;
passing a portion of the overhead stream back to the top of said rectifier column as a reflux stream, the pressure of said reflux stream being increased above the pressure of said overhead stream;
introducing the bottom stream of said rectifier column as a feed to a demethanizer column; and returning the top stream of said demethanizer column as a bottom feed to said rectifier column.
introducing the feedstream into a rectifier column to recover ethane from the feedstream and withdrawing methane as a overhead stream;
passing a portion of the overhead stream back to the top of said rectifier column as a reflux stream, the pressure of said reflux stream being increased above the pressure of said overhead stream;
introducing the bottom stream of said rectifier column as a feed to a demethanizer column; and returning the top stream of said demethanizer column as a bottom feed to said rectifier column.
2. The process of Claim 1 and in addition, condensing a portion of said reflux stream after the pressure of said stream is increased.
3. The process of Claim 2, wherein said portion of the reflux stream is condensed by cooling with the overhead stream of said rectifier column.
4. The process of Claim 1, wherein the rectifier column and demethanizer column are separate vessels.
5. The process of Claim 1, wherein the rectifier column and demethanizer column are part of a common vessel.
6. The process of Claim 1, wherein the reflux stream comprises less than 25% of the overhead stream.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US32436181A | 1981-11-24 | 1981-11-24 | |
| US324,361 | 1981-11-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1184210A true CA1184210A (en) | 1985-03-19 |
Family
ID=23263270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000416076A Expired CA1184210A (en) | 1981-11-24 | 1982-11-22 | Cryogenic gas plant |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1184210A (en) |
| GB (1) | GB2110808B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0137744B2 (en) * | 1983-09-20 | 1991-08-28 | Costain Petrocarbon Limited | Separation of hydrocarbon mixtures |
| GB2146751B (en) * | 1983-09-20 | 1987-04-23 | Petrocarbon Dev Ltd | Separation of hydrocarbon mixtures |
| EP0318504B1 (en) * | 1986-08-06 | 1991-06-12 | Linde Aktiengesellschaft | Process for separating higher hydrocarbons from a gas mixture |
| GB2224036B (en) * | 1988-10-21 | 1992-06-24 | Costain Eng Ltd | Separation of gas & oil mixtures |
| US5673571A (en) * | 1996-03-06 | 1997-10-07 | Manley; David B. | Deethanizer/depropanizer sequences with thermal and thermo-mechanical coupling and component distribution |
-
1982
- 1982-11-22 GB GB08233219A patent/GB2110808B/en not_active Expired
- 1982-11-22 CA CA000416076A patent/CA1184210A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2110808B (en) | 1985-04-17 |
| GB2110808A (en) | 1983-06-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2682991B2 (en) | Low temperature separation method for feed gas | |
| US4251249A (en) | Low temperature process for separating propane and heavier hydrocarbons from a natural gas stream | |
| JP5793145B2 (en) | Hydrocarbon gas treatment | |
| EP0095739B1 (en) | Nitrogen rejection from natural gas with co2 and variable n2 content | |
| US4617039A (en) | Separating hydrocarbon gases | |
| EP0231949B2 (en) | Process to separate nitrogen and methane | |
| US4415345A (en) | Process to separate nitrogen from natural gas | |
| US5992175A (en) | Enhanced NGL recovery processes | |
| CA2664224C (en) | Hydrocarbon gas processing | |
| CA1123334A (en) | Cryogenic process for separating synthesis gas | |
| US4752312A (en) | Hydrocarbon gas processing to recover propane and heavier hydrocarbons | |
| CA1250220A (en) | Process for the separation of a c in2 xx hydrocarbon fraction from natural gas | |
| CA2012611C (en) | Cryogenic rectification process for separating nitrogen and methane | |
| US3702541A (en) | Low temperature method for removing condensable components from hydrocarbon gas | |
| US4456461A (en) | Separation of low boiling constituents from a mixed gas | |
| NO312858B1 (en) | Process for producing ethane and system for carrying out the process | |
| US4444577A (en) | Cryogenic gas processing | |
| US4496380A (en) | Cryogenic gas plant | |
| US4952305A (en) | Process and apparatus for the separation of hydrocarbons | |
| CA1187034A (en) | Processing produced fluids of high pressure gas condensate reservoirs | |
| US4617038A (en) | Process for using preferential physical solvents for selective processing of hydrocarbon gas streams | |
| EP0252660A2 (en) | Method for recovery of natural gas liquids | |
| CA1184210A (en) | Cryogenic gas plant | |
| JPS63166402A (en) | Method of separating hydrocarbon | |
| WO1990010837A1 (en) | Process for cryogenically separating natural gas streams |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |