US 6,023,942 A · Process for liquefaction of natural gas

Abstract

This invention relates to a process for liquefying a gas stream rich in methane and having a pressure above about 3103 kPa (450 psia). The gas stream is expanded to a lower pressure to produce a gas phase and a liquid product having a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the liquid product to be at or below its bubble point. The gas phase and the liquid product are then phase separated in a suitable separator, and the liquid product is introduced to a storage means for storage at a temperature above about -112.degree. C. (-170.degree. F.).

Claims29

Dependent claims

A process for liquefying a gas stream rich in methane which comprises the steps of:

(a) providing the gas stream at a pressure above about 3103 kPa (450 psia);
(b) expanding the gas stream to a lower pressure to produce a gas phase and a liquid product having a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the liquid product to be at or below its bubble point;
(c) phase separating the gas phase and the liquid product;
and
(d) introducing the liquid product to a storage means for storage at a temperature above about -112.degree. C. (-170.degree. F.).

2 more elements

A process for liquefing a gas stream rich in methane and having a pressure above about 3103 kPa (450 psia) which comprises the steps of

(a) phase separating the gas stream into a first gas stream and a first liquid stream;
(b) passing the first liquid stream to a demethanizer column;
(c) compressing and cooling the first gas stream, thereby producing gas and liquid phases;
(d) phase separating the gas and liquid phases of step (c) to produce a second gas stream and a second liquid stream;
(e) expanding at least a portion of the second gas stream to a lower pressure whereby the second gas stream is further cooled;
(f) supplying the second liquid stream and the expanded second gas stream to the demethanizer column;
(g) removing from the upper region of the demethanizer column a third gas stream, the third gas stream comprising predominantly methane, and passing the third gas stream through a heat exchanger to warm the third gas stream;
(h) removing from the demethanizer a third liquid stream and passing the third liquid stream to a fractionation system having at least one fractionation column and having at least one overhead vapor stream;
(i) combining the warmed third gas stream of step (g) and the overhead vapor stream of step (h) and compressing the combined stream;
(j) cooling the compressed combined stream;
(k) dividing the cooled compressed stream of step (j) into a first cooled stream and a second cooled stream and passing the first cooled stream through the heat exchanger of step (g) to further cool the first cooled stream;
(l) expanding the first cooled stream to produce gas and liquid phases;
(m) phase separating the gas and liquid phases of step (l) in a phase separator, thereby producing a methane-rich liquefied natural gas at a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the methane-rich liquefied natural gas to be at or below its bubble point;
(n) expanding the second cooled stream of step (k) to a lower pressure whereby it is further cooled, producing gas and liquid phases;
(o) phase separating the gas and liquid phases produced in step (n);
and
(p) passing the liquid phase of step (o) to the phase separator of step (m).

14 more elements

A process for liquefying a gas stream rich in methane which comprises the steps of:

(a) compressing the gas stream to a pressure greater than 3103 kPa (450 psia);
(b) phase separating the gas stream into a first gas stream and a first liquid stream;
(c) passing the first liquid stream to a demethanizer column;
(d) compressing and cooling the first gas stream without use of a closed-loop refrigeration system, thereby producing gas and liquid phases;
(e) phase separating the gas and liquid phases of step (d) to produce a second gas stream and a second liquid stream;
(f) expanding at least a portion of the second gas stream to a lower pressure whereby it is further cooled;
(g) supplying the second liquid stream and the expanded second gas stream to the demethanizer column;
(h) removing from the upper region of the demethanizer column a vapor stream, the vapor stream comprising predominantly methane, and passing the vapor stream through a heat exchanger to warm the vapor stream;
(i) removing from the demethanizer a liquid stream and passing the liquid stream to a fractionation system having at least one fractionation column and having at least one overhead vapor stream;
(j) combining the warmed vapor stream of step (h) and the overhead vapor stream of step (i) and compressing the combined stream;
(k) cooling the compressed combined stream of step (j) without use of a closed-loop refrigeration system;
(l) dividing the cooled compressed stream of step (k) into a first cooled stream and a second cooled stream and passing the first cooled stream through the heat exchanger of step (h) to further cool the first cooled stream;
(m) expanding the first cooled stream to produce gas and liquid phases;
(n) phase separating the gas and liquid phases of step (m) in a phase separator, thereby producing a methane-rich liquefied natural gas having a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the methane-rich liquefied natural gas to be at or below its bubble point;
(o) expanding the second cooled stream of step (l) to a lower pressure whereby it is further cooled, producing gas and liquid phases;
(p) phase separating the gas and liquid phases produced in step (o);
and
(q) passing the liquid phase of step (o) to the phase separator of step (n).

15 more elements

Dependencies are inferred from the claim text.

Abstract

Claims29

Dependent claims

A process for liquefying a gas stream rich in methane which comprises the steps of:

(a) providing the gas stream at a pressure above about 3103 kPa (450 psia);
(b) expanding the gas stream to a lower pressure to produce a gas phase and a liquid product having a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the liquid product to be at or below its bubble point;
(c) phase separating the gas phase and the liquid product;
and
(d) introducing the liquid product to a storage means for storage at a temperature above about -112.degree. C. (-170.degree. F.).

2 more elements

A process for liquefing a gas stream rich in methane and having a pressure above about 3103 kPa (450 psia) which comprises the steps of

(a) phase separating the gas stream into a first gas stream and a first liquid stream;
(b) passing the first liquid stream to a demethanizer column;
(c) compressing and cooling the first gas stream, thereby producing gas and liquid phases;
(d) phase separating the gas and liquid phases of step (c) to produce a second gas stream and a second liquid stream;
(e) expanding at least a portion of the second gas stream to a lower pressure whereby the second gas stream is further cooled;
(f) supplying the second liquid stream and the expanded second gas stream to the demethanizer column;
(g) removing from the upper region of the demethanizer column a third gas stream, the third gas stream comprising predominantly methane, and passing the third gas stream through a heat exchanger to warm the third gas stream;
(h) removing from the demethanizer a third liquid stream and passing the third liquid stream to a fractionation system having at least one fractionation column and having at least one overhead vapor stream;
(i) combining the warmed third gas stream of step (g) and the overhead vapor stream of step (h) and compressing the combined stream;
(j) cooling the compressed combined stream;
(k) dividing the cooled compressed stream of step (j) into a first cooled stream and a second cooled stream and passing the first cooled stream through the heat exchanger of step (g) to further cool the first cooled stream;
(l) expanding the first cooled stream to produce gas and liquid phases;
(m) phase separating the gas and liquid phases of step (l) in a phase separator, thereby producing a methane-rich liquefied natural gas at a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the methane-rich liquefied natural gas to be at or below its bubble point;
(n) expanding the second cooled stream of step (k) to a lower pressure whereby it is further cooled, producing gas and liquid phases;
(o) phase separating the gas and liquid phases produced in step (n);
and
(p) passing the liquid phase of step (o) to the phase separator of step (m).

14 more elements

A process for liquefying a gas stream rich in methane which comprises the steps of:

(a) compressing the gas stream to a pressure greater than 3103 kPa (450 psia);
(b) phase separating the gas stream into a first gas stream and a first liquid stream;
(c) passing the first liquid stream to a demethanizer column;
(d) compressing and cooling the first gas stream without use of a closed-loop refrigeration system, thereby producing gas and liquid phases;
(e) phase separating the gas and liquid phases of step (d) to produce a second gas stream and a second liquid stream;
(f) expanding at least a portion of the second gas stream to a lower pressure whereby it is further cooled;
(g) supplying the second liquid stream and the expanded second gas stream to the demethanizer column;
(h) removing from the upper region of the demethanizer column a vapor stream, the vapor stream comprising predominantly methane, and passing the vapor stream through a heat exchanger to warm the vapor stream;
(i) removing from the demethanizer a liquid stream and passing the liquid stream to a fractionation system having at least one fractionation column and having at least one overhead vapor stream;
(j) combining the warmed vapor stream of step (h) and the overhead vapor stream of step (i) and compressing the combined stream;
(k) cooling the compressed combined stream of step (j) without use of a closed-loop refrigeration system;
(l) dividing the cooled compressed stream of step (k) into a first cooled stream and a second cooled stream and passing the first cooled stream through the heat exchanger of step (h) to further cool the first cooled stream;
(m) expanding the first cooled stream to produce gas and liquid phases;
(n) phase separating the gas and liquid phases of step (m) in a phase separator, thereby producing a methane-rich liquefied natural gas having a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the methane-rich liquefied natural gas to be at or below its bubble point;
(o) expanding the second cooled stream of step (l) to a lower pressure whereby it is further cooled, producing gas and liquid phases;
(p) phase separating the gas and liquid phases produced in step (o);
and
(q) passing the liquid phase of step (o) to the phase separator of step (n).

15 more elements

Dependencies are inferred from the claim text.

Process for liquefaction of natural gas

Life of this patent

Abstract

Claims29

Process for liquefaction of natural gas

Life of this patent

Abstract

Claims29