| 摘要 |
1310707 Gas liquefaction process INSTITUTE OF GAS TECHNOLOGY 14 July 1970 57459/71 Divided out of 1310706 Heading F4P Cooling to liquefaction temperature of a high pressure substantially pure methane stream 40, Fig. 1, derived either from a feed line 26 or from a de-methanizer 21 supplied with natural gas through a line 36 is effected by passage through heat exchangers 10 to 17, the so-liquefied methane is expanded at a valve 41 to atmospheric storage pressure and the flash gas together with boil-off-gas is returned by a line 50 through exchangers 17 to 10 together with liquid ethane having been withdrawn from a high pressure line 58 and expanded through valves 67, 70, 71, 72, with liquid propane having been withdrawn from a high pressure line 59 and expanded at a valve 74, with liquid butane having been withdrawn from a line 60 and expanded at valves 75, 76 and with liquid pentane having been withdrawn from a line 61 and expanded at a valve 77; said expanded liquid C 2 to C 5 hydrocarbons being evaporated during their passage through exchangers 17 to 10 which are thus cooled, and the mixed vapours, being fed to a compressor 30 delivering through a line 55 to stripper apparatus 20 having components 22, 23, 24 and 25 from which the refrigerant streams of C 2 to C 5 hydrocarbons are obtained. Exchangers 10, 11 are also cooled by evaporation of heavy liquid hydrocarbons withdrawn from methane stream 40 and expanded at valves 51, 52. In a modification the liquid feed stream leaving exchanger 17, Fig. 3, and containing nitrogen helium and/or hydrogen is phase separated at 81 and the liquid methane is further cooled at 19 and expanded at 84 to provide a mixture of liquid and solid methane received in storage vessel 18. Gas from separator 81 is expanded at 88 and together with subcooled liquid methane withdrawn from 18 through a line 89 is used to cool exchanger 19. |
