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US 5,600,969 AGranted
Process and apparatus to produce a small scale LNG stream from an existing NGL expander plant demethanizer
AssigneePhillips Petroleum Company
InventorWilliam R. Low
Life of this patent
Estimating the term…
Abstract
This invention concerns a novel process and apparatus for producing relatively small quantities of liquefied natural gas (LNG) by processing a side stream at a conventional NGL expander gas plant.
Claims20
A process for producing liquefied natural gas at a natural gas expander plant comprising
- (a) withdrawing a methane-rich side stream from the gas overhead stream at the demethanizer;
- (b) expanding said side stream by flowing through a turbo expander thereby producing energy and a two-phase stream;
- (c) splitting said two-phase stream into a first stream and a second stream;
- (d) flowing said first stream and a condensible refrigerant vapor stream to a condenser wherein said first stream functions via indirect heat exchange as a coolant thereby condensing at least a portion of the condensible refrigerant stream and producing a liquid-bearing refrigerant stream and a warmed first stream;
- (e) flashing said refrigerant stream of step (d) thereby creating a flashed refrigerant stream;
- (f) flowing the second stream and at least a portion of the flashed refrigerant stream into an indirect heat exchange means thereby condensing at least a portion of the second stream and producing an LNG-bearing stream and a refrigerant vapor stream.
3 more elements
A process for producing liquefied natural gas at an natural gas expander plant comprising
- (a) withdrawing a methane-rich side stream from the gas overhead stream at the demethanizer;
- (b) expanding the side stream by flowing through a turbo expander thereby producing energy and a two-phase stream;
- (c) separating said two-phase stream into an expanded vapor stream and an expanded liquid stream;
- (d) splitting said expanded vapor stream into a first vapor stream and a second vapor stream;
- (e) cooling a refrigerant vapor stream in a closed refrigerant stream by indirect heat exchange with said first vapor stream thereby producing an at least partially condensed refrigerant and a heated first vapor stream;
- (f) flashing said partially condensed refrigerant;
- and
- (g) cooling said second vapor stream via indirect heat exchange by contact with at least a portion of the product of step (f) thereby producing a second refrigerant vapor and an at least partially condensed natural gas stream.
5 more elements
An apparatus for producing liquefied natural gas from a methane-rich side stream at a gas processing plant comprising
- (a) a first conduit for the methane-rich side stream;
- (b) a turbo expander connected to the first conduit of (a);
- (c) a splitting device connected to the turbo expander and from which is produced a first stream and a second stream;
- (d) a closed refrigeration system nominally comprised of a compressor, condenser, an expansion means, a chiller, necessary refrigerant conduit for connecting the above components in an operational order, and refrigerant;
- (e) a second conduit from said splitting means for delivering the first stream coolant to said condenser;
- (f) a third conduit from said splitting means for delivering said second stream to said evaporative chiller;
- (g) and a fourth conduit from said chiller from which is produced an LNG-bearing stream.
4 more elements
Dependencies are inferred from the claim text.