| 摘要 |
1,213,072. Gas liquefaction process. L'AIR LIQUIDE SOC. ANON. POUR L'ETUDE ET L'EXPLOITATION DES PROCEDES GEORGES CLAUDE. 29 March, 1968 [31 March, 1967], No. 15379/68. Heading F4P. Cooling of a compressed gas mixture, e.g. natural gas, to effect fractional condensation, is effected by passing it from a line 1, Fig. 2, through a nest of tubes 3, 8 within series arranged superposed heat exchangers 11, 12, 13, 21, Fig. 1, from which is discharged L.N.G. through a line 98 to store, and the exchangers are cooled by indirect heat exchange with a reverse flow of a closed cycle refrigerant having been expanded at valves 19, 33, 92, 97 and the so-warmed expanded refrigerant is compressed at 53, cooled in a water condenser 55, separated into condensate and residual gas at 57 which is re-cooled by passage through lines 14, 22 and exchanger 11 in the same direction as the feed gas mixture to provide high pressure liquid refrigerant for valve 19 and partly liquid highpressure refrigerant which is fed through a line 25 to a separator 35 through which passes a section 6 of the feed line 1 and from which separator condensate and residual gas is passed through lines 29, 26 down exchanger 12 to provide liquid refrigerant for valve 33 and wet subcooled refrigerant for a further separator 40. Condensate and residual gas from 40 are cooled in exchanger 13 to provide feed for valve 92 and feed for exchanger 21 and valve 97. The down flow paths in each exchanger comprise nests of coiled tubes whereas the upflow of expanded refrigerant occurs in the shell space of each exchanger. In a modification the separators have their bases common with those of adjacent exchangers and their lateral walls externally of the exchangers. A suitable refrigerant gas mixture comprises 0 to 3% nitrogen, 20 to 32% methane, 34 to 44% ethane, 12 to 20% propane, 8 to 15% butanes and 3 to 8% pentanes and heavier hydrocarbons as described in Specification 1,122,860. |
