| 摘要 |
A low-pressure olefins recovery process and plant are described. The feed gas 300 is compressed 302, 304 and distilled 310 at a primary distillation pressure. The overhead stream 312 is chilled 318 at a pressure less than 30 kg/cm 2 (430 psia) to partially condense the overheads. The primary distillation tower 310 is refluxed with at least a portion of the condensate 320. The overhead vapor is further chilled 318 and partially condensed and the condensate 322 is fed to a demethanizer 324. The remaining vapor 326 is cooled in a cold section 328 and the resultant liquid is phase-separated 330 and expanded 331, 334 to provide refrigeration for the cold ssection. The expanded vapor 332 from the cold section is recycled to the process gas compressor. The bottoms streams 338, 342 from the primary distillation zone and the demethanizer are fractionated into respective streams consisting essentially of ethylene 356, ethane 358, propylene 364, propane 366, C 4 's 346, and C 5+ 348.
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