System and method for improving propane recovery and ethane rejection in a gsp/ expander system
AssigneeBCCK Holding Company
InventorRayburn C. Butts
Life of this patent
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Abstract
A system and method for enhancing propane recovery in a GSP system operated in an ethane rejection mode using an add-on system comprising a heat exchanger and a condenser and optionally a reflux column having 0-5 theoretical stages. An overhead stream from a GSP fractionation column and a subcooled expanded GSP stream are diverted from the typical GSP process for processing in the add-on system to provide an additional reflux stream that increases the amount of ethane and propane that feeds into a top level of the GSP fractionation column. In ethane rejection mode, the add-on system results in an NGL product stream preferably comprising less than 6% of the ethane and at least 97% of the propane from the GSP feed stream.
Claims20
A propane recovery system for increasing propane recovery in an NGL stream produced from a feed stream comprising methane, ethane, and propane in a GSP system operated in an ethane rejection mode, the GSP system comprising a fractionation column to separate a plurality of fractionation column feed streams comprising (1) a first stream comprising a subcooled expanded first part of a separator overhead stream, (2) a second stream comprising a subcooled expanded first part of a separator bottoms stream, (3) a third stream comprising an expanded second part of the separator overhead stream, and (4) a fourth stream comprising an expanded second part of the separator bottoms stream into a fractionation column overhead stream and a fractionation column bottoms stream;
- the propane recovery system comprising:
- a first heat exchanger to warm the first stream through heat exchange with a first set of streams prior to the first stream feeding into the fractionation column;
- a condenser for separating a condenser feed stream into a condenser overhead stream and a condenser bottoms stream;
- wherein the second stream feeds into a top level of the fractionation column;
- wherein the third stream and the warmed first stream feed into an upper level of the fractionation column below where the second stream feeds into the fractionation column;
- wherein the fourth stream feeds into a mid-to-upper level of the fractionation column;
- wherein the NGL stream comprises less than 6% of the ethane in the feed stream and more than 98% of the propane in the feed stream.
A method for increasing propane recovery in an NGL stream produced from a feed stream comprising methane, ethane, and propane in a GSP system operated in an ethane rejection mode, the method comprising:
- (1) separating the feed stream in a separator into a separator overhead stream and a separator bottoms stream;
- (2) splitting the separator overhead stream into a first portion and a second portion;
- (3) splitting the separator bottoms stream into a first portion and a second portion;
- (4) separating a plurality of fractionation column feed streams into a fractionation column overhead stream and a fractionation column bottoms stream in a fractionation column;
- (5) separating a condenser feed stream into a condenser overhead stream and a condenser bottoms stream in a condenser;
- (6) cooling at least a first part of the feed stream in a first heat exchanger through heat exchange with the condenser overhead stream prior to separating the first part of the feed stream step 1;
- (7) cooling a first part of the separator overhead stream and a first part of the separator bottoms stream in a second heat exchanger through heat exchange with the condenser overhead stream in a second heat exchanger prior to the condenser overhead stream undergoing heat exchange in the first heat exchanger in step 6;
- (8) expanding the first part of the separator overhead stream after cooling in the second heat exchanger;
- (9) warming the first part of the separator overhead stream after expanding in step 8 in a third heat exchanger through heat exchange with a first set of streams;
- (10) expanding the first part of the separator bottoms stream after heat exchange in the second heat exchanger in step 6;
- (11) expanding a second portion of the separator overhead stream;
- (12) expanding a second part of the separator bottoms stream;
- wherein the plurality of fractionation column feed streams comprise:
- (a) the first part of the separator bottoms stream after expanding in step 10;
- (b) the first part of the separator overhead stream after the heat exchange in step 9;
- (c) the second part of the separator overhead stream after expanding in step 11;
- and (d) the second part of the separator bottoms stream after expanding in step 12.
Dependencies are inferred from the claim text.