US3589137A
Expired / Lapsed
US
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Method and apparatus for separating nitrogen and hydrocarbons by fractionation using the fluids-in-process for condenser and reboiler duty
Assignee: McDonnell Douglas Corp
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Filing: 1967-10-12
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Granted: 1971-06-29
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Expires: 1987-10-12
Abstract
Abstract System for the separation of gases, particularly of mixtures of a low-boiling hydrocarbon and nitrogen, e.g., a mixture of methane and nitrogen, which involves, according to one embodiment, providing a mixture of such low-boiling hydrocarbon and nitrogen at relatively high pressure, e.g., about 800 p.s.i., cooling the compressed gas mixture approximately to its saturation temperature, passing the cooled compressed mixture in heat exchange relation along the lower portion of a fractionating column operating at a pressure substantially lower than the pressure of the compressed gas mixture, and providing reboil heat to the column, reducing the pressure of the compressed mixture approximately to the pressure in the column, introducing the resulting mixture as feed into the fractionating column, withdrawing nitrogen as overhead from the column, and withdrawing the low-boiling hydrocarbon in substantially pure liquid form from the lower portion of the column, passing overhead nitrogen in heat exchange relation along the upper portion of the column, work expanding the exiting nitrogen and recycling the expanded nitrogen again in heat exchange relation along the upper portion of the column, to provide condensing duty in the column, throttling a portion of the liquid hydrocarbon withdrawn from the column and passing the throttled hydrocarbon in heat exchange relation along the upper portion of the column to provide the balance of the condensing duty required for effecting the separation in the column, passing the exiting vaporized methane and the main portion of the liquid methane withdrawn from the column in heat exchange relation with the compressed feed mixture for cooling same, and compressing the methane product to desired pressure, and passing nitrogen withdrawn from heat exchange relation with the compressed gas mixture for cooling same, the separation of the gas mixture in said column being carried out by nonadiabatic differential distillation and thus increasing the efficiency of the system.
Inventors
- 👤 Michael L Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:26
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/0228; F25J3/0233; F25J3/0204; F25J3/0209; F25J3/0257; F25J2200/00; F25J2200/02; F25J2200/80; F25J2235/00; F25J2235/60; F25J2240/00; F25J2240/02; F25J2240/12; F25J2270/00; F25J2270/04; F25J2270/06; F25J2270/12; F25J2270/42; Y; Y10; Y10S; Y10S62/00; Y10S62/927
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
13 words
A process as defined in claim 1, wherein said low-boiling hydrocarbon is methane.
Claim 2
Dependent Claim
63 words
A process as defined in claim 1, wherein said low-boiling hydrocarbon is methane, and wherein said further condensing duty is provided by separating a portion of liquid methane withdrawn from the lower portion of said column, throttling and cooling said separated portion of methane, and passing said throttled and cooled methane in heat exchange relation along the upper portion of said fractionating column.
Claim 3
Dependent Claim
54 words
A process as defined in claim 3, and wherein said reduction of the pressure of said cOmpressed feed mixture is accomplished by throttling said compressed mixture after passage thereof in heat exchange relation along the lower portion of said column, to a reduced temperature and to a pressure approximately the pressure in said column.
Claim 4
Dependent Claim
58 words
A process as defined in claim 1, wherein said feed gas mixture consists essentially of about 70 percent methane and about 30 percent nitrogen, said nitrogen-methane feed mixture being initially compressed to about 1,000 p.s.i., and which includes delivering the liquid methane withdrawn from the lower portion of the column as product at pressure of about 800 p.s.i.
Claim 5
Dependent Claim
64 words
A process as defined in claim 1, wherein said expanded nitrogen withdrawn from heat exchange relation from the upper portion of said column is passed in heat exchange relation with said compressed feed gas mixture for cooling same, and wherein said hydrocarbon withdrawn from the lower portion of said column is passed in heat exchange relation with said feed gas mixture for cooling same.
Claim 6
Dependent Claim
139 words
A process as defined in claim 3, and including passing the exiting expanded nitrogen recycled in heat exchange relation along said fractionating column, in heat exchange relation with said compressed feed gas mixture, pumping the major portion of liquid methane withdrawn from the lower portion of the column up to desired delivery pressure, and passing said pumped liquid hydrocarbon in heat exchange relation with said feed gas mixture for cooling same, passing the remaining minor portion of methane throttled and vaporized along the upper portion of said main fractionating column into heat exchange relation with said feed gas mixture for cooling same, and compressing said last-mentioned minor portion of methane and mixing same with said major portion of pumped liquid methane and delivering the resulting methane as product at a pressure somewhat below the pressure of feed gas mixture.
Claim 7
Dependent Claim
67 words
A process in claim 1, including passing a portion of said work expanded nitrogen into heat exchange relation with a portion of said hydrocarbon withdrawn from the lower portion of the column, to subcool said hydrocarbon, throttling said subcooled hydrocarbon to reduce the pressure and temperature thereof, and passing said throttled hydrocarbon along the upper portion of the fractionating column to supply said further condensing duty therefor.
Claim 8
Dependent Claim
108 words
A process as defined in claim 3, wherein a portion of the work-expanded nitrogen is passed in heat exchange relation with a portion of the methane withdrawn from the lower portion of the column, to subcool said liquid methane, prior to throttling of said liquid methane and prior to passage thereof in heat exchange relation along the upper portion of the column, and including passing the exiting methane withdrawn from heat exchange relation with the upper portion of the column, in heat exchange relation with the feed gas mixture, and passing the exiting heated nitrogen into heat exchange relation with the compressed feed gas mixture for cooling same.
Claim 9
Dependent Claim
75 words
A process as defined in claim 1, wherein said compressed feed mixture is first reduced in pressure to an intermediate pressure higher than the pressure in said column prior to entering into heat exchange relation along the lower portion of said column, and after passage in heat exchange relation with said column, the exiting feed gas mixture is then reduced in pressure approximately to the pressure in the column prior to introduction as feed therein.
Claim 10
Dependent Claim
129 words
A process as defined in claim 3, wherein said compressed feed gas mixture is first precooled by passage in heat exchange relation with liquid in a reboiler in fluid communication with the lower portion of said column, and said precooled compressed feed gas mixture is then further cooled by passage in heat exchange relation with said nitrogen prior to expansion thereof, and with said expanded nitrogen, and also in heat exchange relation with throttled methane exiting from heat exchange relation with the upper portIon of said column, and said further cooled mixture is throttled to an intermediate pressure above the pressure in said column prior to said passing of such cooled compressed mixture in heat exchange relation along the lower portion of said column for providing reboil heat therein.
Claim 11
Dependent Claim
53 words
A process as defined in claim 1, wherein said work-expanded nitrogen exiting from heat exchange relation with the column is further work expanded to a reduced pressure and temperature and the further expanded nitrogen again passed in heat exchange relation along the upper portion of said column for providing additional condensing duty therein.
Claim 12
Independent Claim
242 words
A system for the separation of the components of a mixture of gases, which comprises a fractionating column, a first passage means for passing a cooled compressed gas mixture in heat exchange relation upwardly along the entire lower portion of said fractionating column, means for reducing the pressure of said gas mixture exiting said first passage means, means for directly introducing the resulting gas mixture as feed into the fractionating column intermediate the ends thereof, to effect a separation of said mixture in said column, means for directly recycling fluid from the upper end of said fractionating column downwardly into heat exchange relation along approximately the entire upper portion of said fractionating column, means for work expanding recycled fluid from said last-mentioned means, a second passage means in heat exchange relation along approximately the entire upper portion of said column, for passing said work expanded fluid therethrough, means for withdrawing work-expanded fluid from said last-mentioned means, means for withdrawing fluid product from the lower portion of said fractionating column, means for separating a portion of said last-mentioned fluid, means for reducing the pressure of said last-mentioned portion of fluid, a third passage means for directly passing said last-mentioned portion of fluid in heat exchange relation vertically along approximately the entire upper portion of said column, and means for delivering said last-mentioned portion of fluid and the remainder of the fluid withdrawn from the bottom of said fractionating column under pressure as product.
Claim 13
Dependent Claim
51 words
A system as defined in claim 13, including means for conducting a portion of the work expanded fluid into heat exchange relation with said portion of fluid withdrawn from the lower portion of said column, prior to reducing the pressure thereof and prior to introducing same into said third passage means.
Claim 14
Dependent Claim
146 words
A system as defined in claim 13, including a main heat exchanger, conduit means for passage of compressed feed gas mixture through said heat exchanger and communicating with the lower end of said first passage means, conduit means connecting the discharge end of said second passage means and passing through said heat exchanger, means for pumping a major portion of fluid withdrawn from the lower end of said fractionating column to a predetermined delivery pressure, means for conducting said last-mentioned major portion of fluid through said heat exchanger, means for passing a minor portion of separated fluid withdrawn from the lower portion of said column and exiting said third passage means through said heat exchanger, and means for compressing the exiting last-mentioned portion of fluid to said predetermined pressure, and for mixing said major and minor portions of fluids, and withdrawing said last-mentioned mixture as product.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |