# US 2009/0260392 A1 · Method of liquefying a hydrocarbon-rich fraction

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- Number: US 2009/0260392 A1
- Document ID: US20090260392A1
- Status: Published application
- Kind: A1
- Application number: 12/425,064
- Filed: 2009-04-16
- Published: 2009-10-22
- Earliest claimed: 2008-04-17
- Assignees: Linde Aktiengesellschaft
- Inventors: Hans SCHMIDT
- Web page: https://patentgrep.com/patent/US20090260392A1

## CPC

- F25J 1/0022: {Hydrocarbons, e.g. natural gas}
- F25J 1/0052: {by vaporising a liquid refrigerant stream}
- F25J 1/0055: {originating from an incorporated cascade}
- F25J 1/0212: {as a single flow MCR cycle}
- F25J 1/025: {Details related to the refrigerant production or treatment, e.g. make-up supply from feed gas itself}
- F25J 1/0262: {Details of the cold heat exchange system (constructional details F25J5/00, construction of cold-exchangers in general F28)}
- F25J 1/0291: {Refrigerant compression by combined gas compression and liquid pumping}
- F25J 2220/64: Separating heavy hydrocarbons, e.g. NGL, LPG, C4+ hydrocarbons or heavy condensates in general
- F25J 2245/90: the recycled stream being boil-off gas from storage
- F25J 2290/32: Details on header or distribution passages of heat exchangers, e.g. of reboiler-condenser or plate heat exchangers
- F25J: LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE (cryogenic pumps F04B37/08; gas storage vessels, gas holders F17; filing vessels with, or discharging from vessels, compressed, liquefied or solidified gases F17C; refrigeration machines, plants, or systems F25B)}

## Abstract

For liquefying a hydrocarbon-rich fraction, in particular natural gas, the hydrocarbon-rich fraction which is to be liquefied is merely cooled and liquefied against a coolant mixture, and the coolant mixture, before its cooling, is separated into a gas phase and a liquid phase, and wherein the gas (5) and the liquid phases (6) are cooled (E) separately and not until after cooling (E) has been performed are they expanded (a, b) and recombined (8).

## Claims

### Claim 1

A method comprising liquefying a hydrocarbon-rich fraction, in particular natural gas, wherein the hydrocarbon-rich fraction which is to be liquefied is cooled and liquefied against a coolant mixture, and the coolant mixture, before cooling, is separated in a separator (D) into a gas phase (5) and a liquid phase (6), the improvement wherein the gas phase (5) and the liquid phase (6) are cooled (E) separately and not until after cooling (E) has been performed are they expanded (a, b) and recombined.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the expanded gas (5) and liquid (6) phases are recombined before or after warming (E) thereof against the hydrocarbon-rich fraction (1) which is to be liquefied.

### Claim 3 (depends on 1)

A method according to claim 1, comprising a preceding step of separating a fraction rich in heavy hydrocarbons from the hydrocarbon-rich fraction which is to be cooled.

### Claim 4 (depends on 1)

A method according to claim 1, wherein the coolant mixture comprises nitrogen, methane, ethane, ethylene, propane, butane and/or pentane.

### Claim 5 (depends on 3)

A method according to claim 3, wherein at least some of the hydrocarbon-rich fraction (1) which is to be cooled, the fraction rich in relatively heavy hydrocarbons and has been separated off, and/or the resultant liquefied hydrocarbon-rich fraction (2) is added to the coolant mixture.

### Claim 6 (depends on 1)

A method according to claim 1, wherein the resultant liquefied hydrocarbon-rich fraction is stored temporarily in a storage vessel, characterized in that recycle gas in the storage vessel is at least in part added to the coolant mixture.

### Claim 7 (depends on 1)

A method according to claim 1, wherein the coolant mixture is compressed to a final pressure in at least two stages, wherein liquid fraction(s) formed at an intermediate pressure after the cooling of the compressed coolant mixture is or are pumped to the final pressure of compression (V) and fed to the separator (D) for separating the coolant mixture.

### Claim 8 (depends on 2)

A method according to claim 2, wherein the expanded gas and liquid phases are recombined before said warming.

### Claim 9 (depends on 2)

A method according to claim 2, wherein the expanded gas and liquid phases are recombined after said warming.

### Claim 10 (depends on 5)

A method according to claim 5, wherein at least some of the methane is replaced.

### Claim 11 (depends on 6)

A method according to claim 6, wherein at least some of the nitrogen is replaced.

### Claim 12 (depends on 6)

A method according to claim 6, wherein the coolant mixture is compressed to a final pressure in at least two stages, wherein liquid fraction(s) formed at an intermediate pressure after the cooling of the compressed coolant mixture is or are pumped to the final pressure of compression (V) and fed to the separator (D) for separating the coolant mixture.