Treating Liquefied Natural Gas
First Claim
1. A method of treating liquefied natural gas supplied at liquefaction pressure containing components having low boiling points to obtain a liquid product stream having a reduced content of components having low boiling points, which method comprises the steps of:
- (a) allowing the liquefied gas to expand to separation pressure to obtain an expanded two-phase fluid;
(b) introducing the expanded two-phase fluid into a column below a gas-liquid contacting section arranged in the column;
(c) collecting in the bottom of the column liquid from the two-phase fluid and withdrawing from the bottom of the column a liquid stream having a reduced content of components having low boiling points;
introducing the liquid stream into a flash vessel at a low pressure;
removing a second gaseous stream from the top of the flash vessel; and
removing from the bottom of the flash vessel a liquid stream to obtain the liquid product stream;
(d) allowing vapor from the two-phase fluid to flow through the contacting section;
(e) withdrawing from the top of the column a gaseous stream that is enriched in components having low boiling points;
(f) heating the gaseous stream obtained in step (e) in a heat exchanger to obtain a heated gaseous stream;
(g) compressing the heated gaseous stream obtained in step (f) to fuel gas pressure to obtain fuel gas;
(h) separating a recycle stream from the fuel gas obtained in step (g);
(i) at least partly condensing the recycle stream obtained in step (h) to obtain a reflux stream; and
(j) introducing the reflux stream obtained in step (i) at separation pressure into the column above the contacting section.
1 Assignment
0 Petitions
Accused Products
Abstract
Method of treating liquefied natural gas (1) to obtain a liquid stream (21) having a reduced content of components having low boiling points comprising expanding (3) the liquefied gas to expand to obtain expanded two-phase fluid; introducing the two-phase fluid into a column (10) below a gas-liquid contacting section (14); withdrawing from the bottom (16) a liquid-stream (17) having a reduced content of components having low boiling points; withdrawing from the top (23) of the column (10) a gaseous stream (25) enriched in components having low boiling points; heating the gaseous stream in a heat exchanger (27); compressing (30) the stream to fuel gas pressure to obtain fuel gas (33); separating a recycle stream (34a) from the fuel gas; at least partly condensing (27) the recycle stream to obtain a reflux stream (34b); and introducing the reflux stream (34b) into the column (10) above the contacting section (14).
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Citations
11 Claims
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1. A method of treating liquefied natural gas supplied at liquefaction pressure containing components having low boiling points to obtain a liquid product stream having a reduced content of components having low boiling points, which method comprises the steps of:
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(a) allowing the liquefied gas to expand to separation pressure to obtain an expanded two-phase fluid;
(b) introducing the expanded two-phase fluid into a column below a gas-liquid contacting section arranged in the column;
(c) collecting in the bottom of the column liquid from the two-phase fluid and withdrawing from the bottom of the column a liquid stream having a reduced content of components having low boiling points;
introducing the liquid stream into a flash vessel at a low pressure;
removing a second gaseous stream from the top of the flash vessel; and
removing from the bottom of the flash vessel a liquid stream to obtain the liquid product stream;
(d) allowing vapor from the two-phase fluid to flow through the contacting section;
(e) withdrawing from the top of the column a gaseous stream that is enriched in components having low boiling points;
(f) heating the gaseous stream obtained in step (e) in a heat exchanger to obtain a heated gaseous stream;
(g) compressing the heated gaseous stream obtained in step (f) to fuel gas pressure to obtain fuel gas;
(h) separating a recycle stream from the fuel gas obtained in step (g);
(i) at least partly condensing the recycle stream obtained in step (h) to obtain a reflux stream; and
(j) introducing the reflux stream obtained in step (i) at separation pressure into the column above the contacting section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification