Liquefaction of natural gas at supercritical pressure employing a single refrigeration cycle

摘要

1,105,374. Gas liquefication processes. LUMMUS CO. 16 Feb., 1966 [18 Feb., 1965], No. 6788/66. Addition to 1,016,049. Heading F4P. Liquefaction of a hydrocarbon gas, e.g. natural methane, is effected by compressing at 13SP1/SP feed gas to a pressure between 40 atoms. and about 1À5 times its critical pressure, cooling by indirect heat exchange at 18SP1/SP, 19SP1/SP with an expanded refrigerant, e.g. propylene, liquefying by indirect heat exchange at 20SP1/SP, 21SP1/SP with a further expanded refrigerant, e.g. ethylene, expanding at a valve 96 into a drum 95, withdrawing condensate therefrom and sequentially, expanding at valves 29SP1/SP, 33SP1/SP, 37SP1/SP into flash drums 30SP1/SP, 34SP1/SP, 38SP1/SP withdrawing product liquefied gas from drum 38SP1/SP at about atmospheric pressure and feeding it to a storage container 43SP1/SP. Gaseous overheads withdrawn from drums 95, 30SP1/SP, 34SP1/SP, 38SP1/SP are compressed at 461 and recycled to the outlet of compressor 13SP1/SP at a point either up or downstream of heat exchanger 18SP1/SP. A portion of gaseous overhead from drum 95 is withdrawn as fuel gas.