| 摘要 |
<p>1376678 Gas liquefaction process SNAM PROGETTI SpA 10 March 1972 [30 March 1971] 11427/72 Heading F4P A permanent gas, e.g. nitrogen, is passed, at a pressure above its critical pressure, into a heat exchanger 1, where it is liquefied by heat exchange with LNG at a temperature below the critical temperature of the nitrogen, the LNG feed pressure being sufficiently high to produce LNG under sufficient pressure for feeding direct to a distribution network. Nitrogen gas at ambient temperature and 0À1 kg/cm<SP>2</SP> gauge is cooled and compressed in three stages by the exchange 1 and compressors 12, 13, 14, the liquefied gas being expanded through a valve 5 into the h.p. stage 4 of a three-stage phase separator tower 16. Liquid from stage 4 is fed through expansion valve 6 to stage 3 and liquid from stage 3 is fed through expansion valve 7 to stage 2. The gas from the stages 2, 3, 4 is fed to the inlet of compressors 12, 13, 14 respectively, and product liquid nitrogen at atmospheric pressure is drawn off from stage 2. The LNG is pumped at a pressure of 71 kg./cm<SP>2</SP> gauge and at -160‹C. from a tank 10 and issues at 15 in liquid form at -110‹ C. and 70 kg./cm<SP>2</SP> gauge.</p> |
