| 摘要 |
1,083,389. Liquefaction of gases. LINDE A.G. Nov. 2, 1965 [Nov. 3, 1964], No.46429165. Heading F4P. Liquefaction of a low boiling point gas or a gas mixture such as natural hydrocarbon gas is effected by forcing it by a compressor 2 at or above its critical pressure, e.g. 200 atmospheres through a plurality of lines 3, 8, 10 in parallel, expanding gas in line 3 in a turbine 4 to the pressure of gas in feed line 1, e.g. 30 atmospheres, using it in an exchanger 6 to cool gas in line 8 and returning it to the feed line 1; gas in lines 8, 10 being cooled in exchangers 9, 11, 12 to or below the critical temperature and expanded in a turbine 13 to 30 atmospheric pressure. Expanded liquid natural gas is then further cooled in an exchanger 15 and is expanded to about atmospheric pressure at a valve 16 into a separating column 17 from the base of which product liquid methane is withdrawn through a duct 18. Nitrogen-rich methane gas and pure methane gas withdrawn through ducts 20, 19 serve to cool exchangers 11, 12, 15 whilst exchanger 9 is cooled by a portion of feed liquid leaving turbine 13 through a line 14 and this liquid then serves to cool exchanger 6 and is assisted by withdrawing a portion of feed gas leaving the compressor 2 through a line 3 expanding it in a turbine 4. The gas leaving the warm end of exchanger 6 is returned to the inlet of the compressor 2. |
