Control method for mixed refrigerant based natural gas liquefier

Patent · Wed Jan 01 04:00:00 EST 2003

OSTI ID:875095

Kountz, Kenneth J ^[1]; Bishop, Patrick M ^[2]

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1. Palatine, IL
2. Chicago, IL

In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig. Refrigerant vapor is introduced from the refrigerant holding tank into the refrigerant circulation circuit until the suction pressure is reduced to below about 15 psig, after which flow of the refrigerant vapor from the refrigerant holding tank is terminated. Natural gas is then introduced into a natural gas liquefier, resulting in liquefaction of the natural gas.

• Research Organization: INSTITUTE OF GAS TECHNOLOGY
• DOE Contract Number: AC02-99CH10978
• Assignee: Gas Technology Institute (Des Plaines, IL)
• Patent Number(s): US 6530240
• OSTI ID: 875095
• Country of Publication: United States
• Language: English

Related Subjects

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15
175
30
350
adjusted
based
below
capacity
circuit
circulation
communication
compressor
control
control method
discharge
exchange
expansion
flow
fluid
fluid communication
gas
holding
initiated
introduced
liquefaction
liquefier
maintained
method
mixed
motor
natural
natural gas
operated
operation
pressure
psig
reduced
refrigerant
resulting
speed
started
storage
storage circuit
suction
tank
terminated
thermal
valve
vapor
variable
variable speed