US3914949A — Method and apparatus for liquefying gases

Claim 1

Independent Claim 275 words

A PROCESS FOR THE LIQUEFACTION OF A GAS CONSISTING ESSENTIALLY OF METHANE, WHICH PROCESS COMPRISES COOLING SAID GAS UNDER PRESSURE BY MEANS OF A REFRIGERATION PROCESS EMPLOYING A REFRIGERANT MOVING THROUGH A SINGLE CLOSED LOOP CYCLE WITHOUT SIDESTREAMS, THE OVERALL COMPOSITION OF THE REFRIGERANT BEING THE SAME AT ALL POINTS IN THE LOOP WITHOUT SEPARATING RESPECTIVE COMPONENTS OF THE REFRIGERANT, SAID REFRIGERATION PROCESS CONSISTING ESSENTIALLY OF: COMPRESSING A REFRIGERANT TO A HIGH PRESSURE, SAID REFRIGERANT CONSISTING ESSENTIALLY OF THE COMPONENTS 30 TO 60 MOLE PERCENT METHANE, 30 TO 60 MOLE PERCENT PROPANE, 0 TO 10 MOLE PERCENT OF OTHER GAS COMPONENTS, THE SUM OF THE MOLE PERCENTS OF METHANE AND PROPANE BEING AT LEAST 90 MOLE PERCENT, COOLING THE HIGH PRESSURE REFRIGERANT TO ABOUT OR BELOW AMBIENT TEMPERATURE, SO THAT AT LEAST 10 MOLE PERCENT OF THE REFRIGERANT IS CONDENSED TO A LIQUID, BY HEAT REJECTION TO A MEMBER OF THE GROUP CONSISTING OF AMBIENT AIR, WATER AND EVAPORATIVE COOLING, AT A TEMPERATURE BELOW ABOUT 120*F, PASSING THE COOLED HIGH PRESSURE REFRIGERANT THROUGH A HEAT EXCHANGER TO REDUCE THE REFRIGERANT TEMPERATURE SUBSTANTIALLY BELOW AMBIENT TEMPERATURE, RESULTING IN SUBCOOLED LIQUID REFRIGERANT, EXPANDING THE COLD HIGH PRESSURE REFRIGERANT THROUGH AN EXPANSION VALVE TO GIVE A COLD LOW PRESSURE REFRIGERANT, AND PASSING THE COLD LOW PRESSURE REFRIGERANT FROM THE EXPANSION VALVE BACK THROUGH THE SAME SAID HEAT EXCHANGER AND THEN TO THE COMPRESSOR TO THEREBY PROVIDE ALL OF THE REFRIGERATION NECESSARY TO BOTH REDUCE THE TEMPERATRE OF THE HIGH PRESSURE REFRIGERANT PASSED THERETHROUGH TO A SUBCOOLED STATE AND HAVE EXTRA REFRIGERATION FOR COOLING SAID PRESSURIZED GAS TO A TEMPERATURE AT WHICH IT CAN BE LIQUEFIED WITHOUT FURTHER REFRIGERATION.

Claim 2

Dependent Claim 275 words

A PROCESS FOR THE LIQUEFACTION OF A GAS CONSISTING ESSENTIALLY OF METHANE, WHICH PROCESS COMPRISES COOLING SAID GAS UNDER PRESSURE BY MEANS OF A REFRIGERATION PROCESS EMPLOYING A REFRIGERANT MOVING THROUGH A SINGLE CLOSED LOOP CYCLE WITHOUT SIDESTREAMS, THE OVERALL COMPOSITION OF THE REFRIGERANT BEING THE SAME AT ALL POINTS IN THE LOOP WITHOUT SEPARATING RESPECTIVE COMPONENTS OF THE REFRIGERANT, SAID REFRIGERATION PROCESS CONSISTING ESSENTIALLY OF: COMPRESSING A REFRIGERANT TO A HIGH PRESSURE, SAID REFRIGERANT CONSISTING ESSENTIALLY OF THE COMPONENTS 30 TO 60 MOLE PERCENT METHANE, 30 TO 60 MOLE PERCENT PROPANE, 0 TO 10 MOLE PERCENT OF OTHER GAS COMPONENTS, THE SUM OF THE MOLE PERCENTS OF METHANE AND PROPANE BEING AT LEAST 90 MOLE PERCENT, COOLING THE HIGH PRESSURE REFRIGERANT TO ABOUT OR BELOW AMBIENT TEMPERATURE, SO THAT AT LEAST 10 MOLE PERCENT OF THE REFRIGERANT IS CONDENSED TO A LIQUID, BY HEAT REJECTION TO A MEMBER OF THE GROUP CONSISTING OF AMBIENT AIR, WATER AND EVAPORATIVE COOLING, AT A TEMPERATURE BELOW ABOUT 120*F, PASSING THE COOLED HIGH PRESSURE REFRIGERANT THROUGH A HEAT EXCHANGER TO REDUCE THE REFRIGERANT TEMPERATURE SUBSTANTIALLY BELOW AMBIENT TEMPERATURE, RESULTING IN SUBCOOLED LIQUID REFRIGERANT, EXPANDING THE COLD HIGH PRESSURE REFRIGERANT THROUGH AN EXPANSION VALVE TO GIVE A COLD LOW PRESSURE REFRIGERANT, AND PASSING THE COLD LOW PRESSURE REFRIGERANT FROM THE EXPANSION VALVE BACK THROUGH THE SAME SAID HEAT EXCHANGER AND THEN TO THE COMPRESSOR TO THEREBY PROVIDE ALL OF THE REFRIGERATION NECESSARY TO BOTH REDUCE THE TEMPERATRE OF THE HIGH PRESSURE REFRIGERANT PASSED THERETHROUGH TO A SUBCOOLED STATE AND HAVE EXTRA REFRIGERATION FOR COOLING SAID PRESSURIZED GAS TO A TEMPERATURE AT WHICH IT CAN BE LIQUEFIED WITHOUT FURTHER REFRIGERATION.

Claim 3

Dependent Claim 71 words

A process according to claim 1 in which the high pressure cooled refrigerant passed to the heat exchanger is at a pressure of about 300 psig to 650 psig and at a temperature below about 110*F., and the cold low pressure refrigerant passed to the heat exchanger from the expansion valve is at a pressure of about 40 psig to 150 psig and at a temperature of about -160*F. to -230*F.

Claim 4

Dependent Claim 32 words

A process according to claim 1 in which the refrigerant is essentially methane and propane in the range of 40 to 60 mole percent methane and 40 to 60 mole percent propane.

Claim 5

Dependent Claim 63 words

A process according to claim 1 in which a natural gas feed stream under pressure is passed through the heat exchanger to cool the natural gas by heat exchange with the cold low pressure refrigerant passed therethrough, and the natural gas after such cooling is directly expanded through an expansion valve to a lower pressure without additional cooling prior to the said expansion.

Claim 6

Dependent Claim 26 words

A process according to claim 2 in which the high pressure refrigerant passed to the heat exchanger is at a temperature of about 40*F. to 80*F.

Claim 7

Dependent Claim 64 words

A process according to claim 2 in which a natural gas feed stream under pressure is passed through the heat exchanger to cool the natural gas by heat exchange with the cold low pressure refrigerant passed therethrough, and the natural gas after such cooling is enthalpically directly expanded through an expansion valve to a lower pressure without additional cooling prior to the said expansion.

Claim 8

Dependent Claim 244 words

A process for the liquefaction of a gas consisting essentially of methane, which process comprises cooling said gas under pressure by means of a refrigeration process employing a refrigerant moving through a single closed loop cycle without sidestreams, the overall composition of the refrigerant being the same at all points in the loop without separating respective components of the refrigerant, said refrigeration process consisting essentially of: compressing a refrigerant consisting essentially of about 40 to 60 mole percent of methane and the remainder propane to a pressure of about 300 to 650 psig, cooling The refrigerant by heat rejection to a member of the group consisting of air, water and evaporative cooling at from 40*F to 120*F, to cool the refrigerant to about 50* to 110*F at about 300 to 650 psig, passing the refrigerant through a heat exchanger to cool the refrigerant to about -160* to -220*F at about 300 to 650 psig, expanding the refrigerant through an expansion valve to bring the refrigerant to about 40 to 150 psig and about -160* to -230*F, and passing the refrigerant from the expansion valve, back through the same heat exchanger and then to the compressor to thereby provide all refrigeration necessary to cool and condense the refrigerant in its initial pass through the heat exchanger at a pressure of about 300 to 650 psig and provide extra refrigeration for cooling said gas to a temperature at which it can be liquefied without further refrigeration.

Claim 9

Dependent Claim 244 words

A process for the liquefaction of a gas consisting essentially of methane, which process comprises cooling said gas under pressure by means of a refrigeration process employing a refrigerant moving through a single closed loop cycle without sidestreams, the overall composition of the refrigerant being the same at all points in the loop without separating respective components of the refrigerant, said refrigeration process consisting essentially of: compressing a refrigerant consisting essentially of about 40 to 60 mole percent of methane and the remainder propane to a pressure of about 300 to 650 psig, cooling The refrigerant by heat rejection to a member of the group consisting of air, water and evaporative cooling at from 40*F to 120*F, to cool the refrigerant to about 50* to 110*F at about 300 to 650 psig, passing the refrigerant through a heat exchanger to cool the refrigerant to about -160* to -220*F at about 300 to 650 psig, expanding the refrigerant through an expansion valve to bring the refrigerant to about 40 to 150 psig and about -160* to -230*F, and passing the refrigerant from the expansion valve, back through the same heat exchanger and then to the compressor to thereby provide all refrigeration necessary to cool and condense the refrigerant in its initial pass through the heat exchanger at a pressure of about 300 to 650 psig and provide extra refrigeration for cooling said gas to a temperature at which it can be liquefied without further refrigeration.

Claim 10

Dependent Claim 12 words

The process of claim 7 in which said gas is natural gas.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-10-27	1979-04-28	1979-10-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-10-27	1983-04-28	1983-10-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-10-27	1987-04-28	1987-10-28	$7700.00	Window Closed / Lapsed

Method and apparatus for liquefying gases

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