| 摘要 |
PURPOSE: To liquefy a nitrogen flow by compressing the nitrogen flow through a multistage compressor to a specified pressure, condensing it through heat exchange and reducing the pressure to produce a two-phase nitrogen flow, separating it to respective phases, supplying a nitrogen vapor flow and collecting the chill thereby generating a nitrogen flow efficiently. CONSTITUTION: A low pressure gas nitrogen flow 90 from a low pressure column is passed through heat exchangers 104, 106 and cooled by LNG and then circulated through compressors 108, 124, 136, 142 and compressed in multistate to a pressure of 350 pis. The highest pressure nitrogen flow 144 is recooled through the heat exchangers 104, 106 and heat exchanged in a heat exchanger 112 with LNG and low temperature return gas nitrogen 164 to produce a supercooled flow 146 which is further supercooled through a downstream heat exchanger 110. That flow 148 is fed to an expander 150 to produce a two-phase nitrogen flow. It is subjected to phase separation at a phase separator 154 and liquid nitrogen is fed through a heat exchanger 168 and a separator 172 to a storage section. The vapor nitrogen 158 is collected to high pressure gas nitrogen 96. |
