| 摘要 |
<p>1,178,006. Gas liquefaction process. L'AIR LIQUIDE S.A. POUR L'ETUDE ET L'EXPLOITATION DES PROCEDES GEORGES CLAUDE. 16 March, 1967 [25 March, 1966], No. 12473/67. Heading F4P. In a process for liquefying varying amounts of a constant supply of main gas, e.g. oxygen produced by a conventional air separating plant 2 by indirect heat exchange at 11 with an auxiliary gas, e.g. nitrogen in a closed cycle comprising a compressor 17 delivering through lines 18, 19 to an expansion turbine 20 which in turn discharges through the exchanger 11 in which the gaseous oxygen is liquefied and a return line 23 to the compressor 17, the degree of cooling of the exchanger 11 is varied in accordance with changes in demand for liquid oxygen by varying the pressure and hence the amount of nitrogen fed to the turbine but maintaining constant the ratio between the feed and exhaust pressures of the turbine. To reduce the cooling of exchanger 11, a portion of the compressed nitrogen is bled through a valve 26 to a storage vessel 24, and since the exhaust pressure of the turbine 26 is lowered the inlet pressure of the compressor 17 is correspondingly lowered. To increase the production of cold in exchanger 11, nitrogen gas is discharged from vessel 24 through a valve 25 to the inlet of compressor 17 with valve 26 closed, resulting in increase in inlet pressure to the turbine 20. Valves 25, 26 may be regulated manually or automatically in accordance with the setting of a valve 8 in a branch line 7 of the main gaseous oxygen supply line 6 by means of a control-unit 42 responsive to pressure in line 6. Make-up for the closed nitrogen cycle is obtained from the nitrogen product line 4 of the apparatus 2. To meet a peak demand for gaseous oxygen, previously liquefied oxygen is withdrawn from a storage vessel 16, vaporized at 33 and fed to line 6.</p> |
