Natural gas processing
First Claim
1. A method for separating higher boiling constituents from a normally gaseous feed mixture containing lower boiling constituents and said higher boiling constituents, at a temperature near atmospheric temperature and at a first elevated pressure substantially above atmospheric pressure, comprising:
- (a) cooling said feed mixture, in a first cooling stage, to a first reduced temperature sufficiently low to liquefy a portion of said feed mixture;
(b) separating the thus cooled feed mixture, in a first separation step, into a first vapor stream and a first liquid stream;
(c) cooling said first vapor stream, in a second cooling stage, to a second reduced temperature sufficiently low to liquefy a portion of said first vapor stream;
(d) separating the thus cooled first vapor stream, in a second separation step, into a second vapor stream and a second liquid stream;
(e) reducing the pressure of said first liquid stream, in a first pressure reduction step, to a second elevated pressure substantially above atmospheric pressure but sufficiently low to flash a portion of said first liquid stream;
(f) reducing the pressure of said second liquid stream, in a second pressure reduction step, to a third elevated pressure substantially above atmospheric pressure and approximately equal to said second elevated pressure but sufficiently low to flash a portion of said second liquid stream;
(g) simultaneously separating the thus reduced-pressure, first liquid stream, in a lower portion of a third separation step, and the thus reduced-pressure, second liquid stream, in an upper portion of said third separation step, into a third vapor stream and a third liquid stream;
(h) expanding at least a portion of said second vapor stream, in an expansion stage, to a fourth elevated pressure substantially above atmospheric pressure and approximately equal to said second and said third elevated pressures but sufficiently low to liquefy a portion of said at least a portion of said second vapor stream;
(i) simultaneously separating the thus expanded at least a portion of said second vapor stream, the remaining portion, if any, of said second vapor stream and said third vapor stream, in an upper portion of a fourth separation step, and said third liquid stream, in a portion of said fourth separation step below said upper portion of said fourth separation step, into a fourth vapor stream, containing a substantially larger proportion of said lower boiling constituents than said feed mixture, and a fourth liquid stream, containing a substantially larger proportion of said higher boiling constituents than said feed mixture; and
(j) collecting said fourth vapor stream and said fourth liquid stream, respectively, as products of said method.
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Accused Products
Abstract
In accordance with the present invention a normally gaseous feed mixture, having a temperature of essentially atmospheric temperature and a pressure substantially above atmospheric pressure, is cooled to a lower temperature sufficient to liquefy a portion of the feed mixture, the cooled feed mixture is separated into a first vapor phase and a first liquid phase, the first vapor phase is further cooled to a temperature sufficiently low to liquefy a portion of the first vapor phase, the cooled first vapor phase is separated into a second vapor phase and a second liquid phase, the pressures of the first liquid phase and the second liquid phase are separately reduced to a pressure sufficiently low to flash portions of the liquid phases, the reduced-pressure, first liquid phase is introduced into the lower portion of a third separation step while the reduced-pressure, second liquid phase is introduced into the upper portion of the third separation step, in which the reduced-pressure, first and second liquid phases are simultaneously separated to produce a third vapor phase and a third liquid phase, at least a portion of the second vapor phase is expanded to a pressure approximately the same as the reduced pressures of the first and second liquid phases but sufficiently low to liquefy a portion of the second vapor phase, the expanded second vapor phase, the remaining portion of the second vapor phase, if any, and the third vapor phase are introduced into the upper portion of a fourth separation step and the third liquid phase is introduced into the fourth separation step at a point below the previously mentioned upper portion of the fourth separation step and the streams introduced into the fourth separation step are simultaneously separated to produce a fourth liquid product enriched in higher boiling components and a fourth vapor product enriched in lower boiling components.
32 Citations
29 Claims
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1. A method for separating higher boiling constituents from a normally gaseous feed mixture containing lower boiling constituents and said higher boiling constituents, at a temperature near atmospheric temperature and at a first elevated pressure substantially above atmospheric pressure, comprising:
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(a) cooling said feed mixture, in a first cooling stage, to a first reduced temperature sufficiently low to liquefy a portion of said feed mixture; (b) separating the thus cooled feed mixture, in a first separation step, into a first vapor stream and a first liquid stream; (c) cooling said first vapor stream, in a second cooling stage, to a second reduced temperature sufficiently low to liquefy a portion of said first vapor stream; (d) separating the thus cooled first vapor stream, in a second separation step, into a second vapor stream and a second liquid stream; (e) reducing the pressure of said first liquid stream, in a first pressure reduction step, to a second elevated pressure substantially above atmospheric pressure but sufficiently low to flash a portion of said first liquid stream; (f) reducing the pressure of said second liquid stream, in a second pressure reduction step, to a third elevated pressure substantially above atmospheric pressure and approximately equal to said second elevated pressure but sufficiently low to flash a portion of said second liquid stream; (g) simultaneously separating the thus reduced-pressure, first liquid stream, in a lower portion of a third separation step, and the thus reduced-pressure, second liquid stream, in an upper portion of said third separation step, into a third vapor stream and a third liquid stream; (h) expanding at least a portion of said second vapor stream, in an expansion stage, to a fourth elevated pressure substantially above atmospheric pressure and approximately equal to said second and said third elevated pressures but sufficiently low to liquefy a portion of said at least a portion of said second vapor stream; (i) simultaneously separating the thus expanded at least a portion of said second vapor stream, the remaining portion, if any, of said second vapor stream and said third vapor stream, in an upper portion of a fourth separation step, and said third liquid stream, in a portion of said fourth separation step below said upper portion of said fourth separation step, into a fourth vapor stream, containing a substantially larger proportion of said lower boiling constituents than said feed mixture, and a fourth liquid stream, containing a substantially larger proportion of said higher boiling constituents than said feed mixture; and (j) collecting said fourth vapor stream and said fourth liquid stream, respectively, as products of said method. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. Apparatus for separating higher boiler constituents from a normally gaseous feed mixture containing lower boiling constituents and said higher boiling constituents, at a temperature near atmospheric temperature and at a first elevated pressure substantially above atmosphermic pressure, comprising:
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(a) first cooling means adapted to cool said normally gaseous feed mixture to a first reduced temperature sufficiently low to liquefy a portion of said feed mixture; (b) first separating means adapted to receive the thus cooled normally gaseous feed mixture and separate said cooled normally gaseous feed mixture into a first vapor stream and a first liquid stream; (c) second cooling means adapted to cool said first vapor stream to a second reduced temperature sufficiently low to liquefy a portion of said first vapor stream; (d) second separating means adapted to receive the thus cooled first vapor stream and separate said cooled, first vapor stream into a second vapor stream and a second liquid stream; (e) first pressure reducing means adapted to reduce the pressure of said first liquid stream to a second elevated pressure substantially above atmospheric pressure but sufficiently low to flash a portion of said first liquid stream; (f) second pressure reducing means adapted to reduce the pressure of said second liquid stream to a third elevated pressure substantially above atmospheric pressure and approximately equal to said second elevated pressure but sufficiently low to flash a portion of said second liquid stream; (g) third separating means adapted to simultaneously receive the thus reduced-pressure, first liquid stream, in a lower portion of said third separating means, and receive the thus reduced-pressure, second liquid stream, in an upper portion of said third separating means, and to simultaneously separate the thus received reduced-pressure, first liquid stream and the thus received reduced-pressure, second liquid stream into a third vapor stream and a third liquid stream; (h) first expansion means adapted to expand at least a portion of said second vapor stream to a fourth elevated pressure substantially above atmospheric pressure and approximately equal to said second and said third elevated pressures but sufficiently low to liquefy a portion of said at least a portion of said second vapor stream; (i) fourth separating means adapted to simultaneously receive the thus expanded at least a portion of the second vapor stream, the remaining portion, if any, of the second vapor stream and said third vapor stream in an upper portion thereof, and said third liquid stream in a portion thereof below said upper portion thereof and to simultaneously separate said expanded at least a portion of said second vapor stream, said remaining portion, if any, of said second vapor stream, said third vapor stream and said third liquid stream into a fourth vapor stream and a fourth liquid stream; (j) means for collecting said fourth vapor stream as a product; and (k) means for collecting said fourth liquid stream as a product. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification