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US 4,415,345 AGranted
Process to separate nitrogen from natural gas
AssigneeUnion Carbide Corporation
InventorBrian R. Swallow
Life of this patent
Estimating the term…
Abstract
A process to separate by rectification low concentration nitrogen from natural gases having a gradually increasing nitrogen concentration which employs a nitrogen heat pump cycle to generate necessary liquid reflux for a fractionation column and is compatible with both single column and double column process arrangements.
Claims13
A process for separating nitrogen from natural gases comprising:
- (a) providing a natural gas feed stream having a nitorgen concentration, which varies over time, of from 1 to 35 percent;
- (b) introducing said nitrogen-containing natural gas stream into a fractionation column operating at a pressure of from 15 to 125 psia;
- (c) separating by recitification said nitrogen-containing natural gas stream into a nitrogen-enriched vapor portion A and a methane-enriched liquid portion B;
- (d) providing a nitrogen-containing vapor stream C;
- (e) warming said nitrogen-containing vapor stream C;
- (f) compressing the warming nitrogen-containing vapor stream C to a pressure of from about 50 to 470 psia;
- (g) cooling the compressed nitrogen-containing stream C by indirect heat exchange with the warming nitrogen-containing stream of step (e);
- (h) condensing the cooled compressed nitrogen-containing stream C by indirect heat exchange with said methane-enriched liquid portion B, thereby providing vapor reflux to the fractionation column;
- (i) throttling the condensed nitrogen-containing liquid stream C to about the pressure of the fractionation column;
- (j) employing the throttled nitrogen-containing liquid stream C to provide liquid reflux for the fractionation column;
- and
- (k) recovering at least a portion of said methane-enriched portion B as product natural gases.
9 more elements
Dependencies are inferred from the claim text.