| 摘要 |
1,170,022. Natural gas separation process. R. R. TRACY and R. G. SPEAR. 16 Jan., 1968 [17 Jan., 1967; 27 Dec., 1967], No. 2244/68. Heading F4P. Separation of natural gas into a hydrocarbon rich fraction and into a relatively low boiling contaminant fraction e.g., nitrogen is effected by cooling compressed feed gas mixture by passage through parallel heat exchangers 24, 25, expansion with partial liquefication in valves 26, 27, separation into liquid and gaseous phases in a vessel 30, continuously withdrawing liquid and gas product streams from vessel 30 through lines 33, 31 and passing at least a portion of each product stream separately through said heat exchangers 24, 25 in counterflow to the feed gas mixture. The feed stream at well head pressure having been cooled, filtered and dried has its pressure reduced to 1500 p.s.i.a. at a valve 23 in feed line 22 and is expanded at valves 26, 27 to about atmospheric pressure; the return flow of liquid fraction through exchanger 24 being effected by a pump 34 for discharge in the gas phase through a line 40, 40A. The nitrogen gas withdrawn from vessel 30 and warmed in exchanger 25 is discharged through a vent line 32. The heat exchangers 24, 25 and expansion valves 26, 27 are periodically purged of condensed solids by closing the feed flow valve 23 and diverting the feed through a regulating valve 42, a heater 43, a line 44 and a valve 45 to back-flow the warm feed; valve 29 being closed and pump 34 being stopped. In a modification purging without interrupting the separation process is effected by duplicating the heat exchangers, expansion valves and flow regulating valves. |
