Hydrocarbon gas processing
First Claim
1. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process(a) said gas stream is treated in one or more heat exchange steps and at least one division step to produce at least a first stream that has been cooled under pressure to condense at least a majority of said first stream, and at least a second stream that has been cooled under pressure;
- (b) said condensed first stream is expanded to a lower pressure whereby said condensed first stream is further cooled, and thereafter supplied at a top feed position on a distillation column that produces at least an overhead vapor stream and a bottom liquid stream;
(c) said cooled second stream is expanded to said lower pressure, and thereafter supplied to said distillation column at a mid-column feed position; and
(d) at least said expanded further cooled first stream and said expanded second stream are fractionated in said distillation column at said lower pressure whereby the components of said relatively less volatile fraction are recovered in said bottom liquid stream and said volatile residue gas fraction is discharged as said overhead vapor stream;
the improvement wherein(1) said overhead vapor stream is directed to an absorbing means housed in a processing assembly to be contacted with a condensed stream and thereby condense less volatile components to form a partially rectified vapor stream;
(2) said partially rectified vapor stream is collected from an upper region of said absorbing means and directed to a heat and mass transfer means housed in said processing assembly, whereby said partially rectified vapor stream is cooled while simultaneously condensing said partially rectified vapor stream'"'"'s less volatile components, thereby forming a further rectified vapor stream and said condensed stream, whereupon said condensed stream is directed to said absorbing means;
(3) said further rectified vapor stream is directed to a heat exchange means housed in said processing assembly and heated, thereafter discharging said heated further rectified vapor stream from said processing assembly as an outlet vapor stream;
(4) said outlet vapor stream is divided into a first portion and a second portion;
(5) said first portion is compressed to higher pressure to form a compressed stream;
(6) said compressed stream is directed to said heat exchange means and cooled to condense at least a majority of said compressed stream, thereby to supply at least a portion of the heating of step (3) and form another condensed stream;
(7) said another condensed stream is expanded to said lower pressure, whereby said another condensed stream is further cooled to form a flash expanded stream;
(8) said flash expanded stream is heated in said heat and mass transfer means, thereby to supply at least a portion of the cooling of step (2) and form a heated flash expanded stream;
(9) said heated flash expanded stream is combined with said second portion to form said volatile residue gas fraction;
(10) said condensed first stream is directed to said heat exchange means and further cooled under pressure, thereby to supply at least a portion of the heating of step (3) and form a further cooled first stream;
(11) said further cooled first stream is expanded to said lower pressure, thereby forming said expanded further cooled first stream;
(12) a distillation liquid stream is collected from a lower region of said absorbing means and combined with said expanded further cooled first stream to form a combined feed stream, whereupon said combined feed stream is directed to said top feed position on said distillation column;
(13) at least said combined feed stream and said expanded second stream are fractionated in said distillation column at said lower pressure whereby the components of said relatively less volatile fraction are recovered in said bottom liquid stream; and
(14) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered in said bottom liquid stream.
3 Assignments
0 Petitions
Accused Products
Abstract
A process and an apparatus are disclosed for a compact processing assembly to improve the recovery of C2 (or C3) and heavier hydrocarbon components from a hydrocarbon gas stream. The preferred method of separating a hydrocarbon gas stream generally includes producing at least a substantially condensed first stream and a cooled second stream, expanding both streams to lower pressure, and supplying the streams to a fractionation tower. In the process and apparatus disclosed, the tower overhead vapor is directed to an absorbing means and a heat and mass transfer means inside a processing assembly. A portion of the outlet vapor from the processing assembly is compressed to higher pressure, cooled and substantially condensed in a heat exchange means inside the processing assembly, then expanded to lower pressure and supplied to the heat and mass transfer means to provide cooling. Condensed liquid from the absorbing means is fed to the tower.
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Citations
34 Claims
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1. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
(a) said gas stream is treated in one or more heat exchange steps and at least one division step to produce at least a first stream that has been cooled under pressure to condense at least a majority of said first stream, and at least a second stream that has been cooled under pressure; -
(b) said condensed first stream is expanded to a lower pressure whereby said condensed first stream is further cooled, and thereafter supplied at a top feed position on a distillation column that produces at least an overhead vapor stream and a bottom liquid stream; (c) said cooled second stream is expanded to said lower pressure, and thereafter supplied to said distillation column at a mid-column feed position; and (d) at least said expanded further cooled first stream and said expanded second stream are fractionated in said distillation column at said lower pressure whereby the components of said relatively less volatile fraction are recovered in said bottom liquid stream and said volatile residue gas fraction is discharged as said overhead vapor stream; the improvement wherein (1) said overhead vapor stream is directed to an absorbing means housed in a processing assembly to be contacted with a condensed stream and thereby condense less volatile components to form a partially rectified vapor stream; (2) said partially rectified vapor stream is collected from an upper region of said absorbing means and directed to a heat and mass transfer means housed in said processing assembly, whereby said partially rectified vapor stream is cooled while simultaneously condensing said partially rectified vapor stream'"'"'s less volatile components, thereby forming a further rectified vapor stream and said condensed stream, whereupon said condensed stream is directed to said absorbing means; (3) said further rectified vapor stream is directed to a heat exchange means housed in said processing assembly and heated, thereafter discharging said heated further rectified vapor stream from said processing assembly as an outlet vapor stream; (4) said outlet vapor stream is divided into a first portion and a second portion; (5) said first portion is compressed to higher pressure to form a compressed stream; (6) said compressed stream is directed to said heat exchange means and cooled to condense at least a majority of said compressed stream, thereby to supply at least a portion of the heating of step (3) and form another condensed stream; (7) said another condensed stream is expanded to said lower pressure, whereby said another condensed stream is further cooled to form a flash expanded stream; (8) said flash expanded stream is heated in said heat and mass transfer means, thereby to supply at least a portion of the cooling of step (2) and form a heated flash expanded stream; (9) said heated flash expanded stream is combined with said second portion to form said volatile residue gas fraction; (10) said condensed first stream is directed to said heat exchange means and further cooled under pressure, thereby to supply at least a portion of the heating of step (3) and form a further cooled first stream; (11) said further cooled first stream is expanded to said lower pressure, thereby forming said expanded further cooled first stream; (12) a distillation liquid stream is collected from a lower region of said absorbing means and combined with said expanded further cooled first stream to form a combined feed stream, whereupon said combined feed stream is directed to said top feed position on said distillation column; (13) at least said combined feed stream and said expanded second stream are fractionated in said distillation column at said lower pressure whereby the components of said relatively less volatile fraction are recovered in said bottom liquid stream; and (14) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered in said bottom liquid stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
(a) one or more heat exchange means and at least one dividing means to produce at least a first stream that has been cooled under pressure to condense at least a majority of said first stream, and at least a second stream that has been cooled under pressure; -
(b) a first expansion means connected to receive said condensed first stream under pressure and expand said condensed first stream to a lower pressure, whereby said first stream is further cooled; (c) a distillation column connected to said first expansion means to receive said expanded further cooled first stream at a top feed position, with said distillation column producing at least an overhead vapor stream and a bottom liquid stream; (d) a second expansion means connected to receive said cooled second stream under pressure and expand said cooled second stream to said lower pressure; (e) said distillation column further connected to said second expansion means to receive said expanded second stream at a mid-column feed position; and (f) said distillation column adapted to fractionate at least said expanded further cooled first stream and said expanded second stream at said lower pressure whereby the components of said relatively less volatile fraction are recovered in said bottom liquid stream and said volatile residue gas fraction is discharged as said overhead vapor stream; the improvement wherein said apparatus includes (1) an absorbing means housed in a processing assembly and connected to said distillation column to receive said overhead vapor stream and contact said overhead vapor stream with a condensed stream, thereby condensing said overhead vapor stream'"'"'s less volatile components and forming a partially rectified vapor stream; (2) a heat and mass transfer means housed in said processing assembly and connected to said absorbing means to receive said partially rectified vapor stream from an upper region of said absorbing means, whereby said partially rectified vapor stream is cooled while simultaneously condensing said partially rectified vapor stream'"'"'s less volatile components, thereby forming a further rectified vapor stream and said condensed stream, said heat and mass transfer means being further connected to said absorbing means to direct said condensed stream to said absorbing means; (3) another heat exchange means housed in said processing assembly and connected to said heat and mass transfer means to receive said further rectified vapor stream and heat said further rectified vapor stream, thereafter discharging said heated further rectified vapor stream from said processing assembly as an outlet vapor stream; (4) a second dividing means connected to said processing assembly to receive said outlet vapor stream and divide said outlet vapor stream into a first portion and a second portion; (5) a compressing means connected to said second dividing means to receive said first portion and compress said first portion to higher pressure, thereby forming a compressed stream; (6) said another heat exchange means further connected to said compressing means to receive said compressed stream and cool said compressed stream to condense at least a majority of said compressed stream, thereby to supply at least a portion of the heating of step (3) and forming another condensed stream; (7) a third expansion means connected to said another heat exchange means to receive said another condensed stream and expand said another condensed stream to said lower pressure, thereby forming a flash expanded stream; (8) said heat and mass transfer means further connected to said third expansion means to receive said flash expanded stream and heat said flash expanded stream, thereby to supply the cooling of step (2) and forming a heated flash expanded stream; (9) a first combining means connected to said heat and mass transfer means and to said second dividing means to receive said heated flash expanded stream and said second portion and form said volatile residue gas fraction; (10) said another heat exchange means further connected to said one or more heat exchange means and said at least one dividing means to receive said condensed first stream and further cool said condensed first stream under pressure, thereby to supply at least a portion of the heating of step (3) and forming a further cooled first stream; (11) said first expansion means being adapted to connect said first expansion means to said another heat exchange means to receive said further cooled first stream and expand said further cooled first stream to said lower pressure, thereby forming said expanded further cooled first stream; (12) a second combining means connected to said absorbing means and to said first expansion means to receive a distillation liquid stream from a lower region of said absorbing means and said expanded further cooled first stream and form a combined feed stream, said second combining means being further connected to said distillation column to supply said combined feed stream at said top feed position of said distillation column; (13) said distillation column being adapted to fractionate at least said combined feed stream and said expanded second stream at said lower pressure whereby the components of said relatively less volatile fraction are recovered in said bottom liquid stream; and wherein quantities and temperatures of said feed streams to said distillation column are controlled to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered in said bottom liquid stream. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification