초록 ▼

A process for treating a purge vent stream from a polymer manufacturing operation, the vent stream containing a polymer, such as ethylene or propylene, and a purge gas, such as nitrogen. The invention involves three separation steps: condensation, flash evaporation and membrane separation. The steps

A process for treating a purge vent stream from a polymer manufacturing operation, the vent stream containing a polymer, such as ethylene or propylene, and a purge gas, such as nitrogen. The invention involves three separation steps: condensation, flash evaporation and membrane separation. The steps are integrated together in such a way as to provide a good separation between the components, and to avoid creation of secondary streams that need additional treatment.

대표청구항 ▼

[ We claim:] [1.] A process for treating a purge stream from a polymer manufacturing operation, said purge stream comprising a monomer and a purge gas, said process comprising the following steps:(a) compressing said purge stream to a pressure no greater than about 1,000 psig;(b) cooling said purge

[ We claim:] [1.] A process for treating a purge stream from a polymer manufacturing operation, said purge stream comprising a monomer and a purge gas, said process comprising the following steps:(a) compressing said purge stream to a pressure no greater than about 1,000 psig;(b) cooling said purge stream to a temperature no lower than about -100.degree. C., resulting in partial condensation of said purge stream, thereby dividing said purge stream into a condensed portion enriched in said monomer and an uncondensed portion enriched in said purge gas;(c) flash evaporating said condensed portion to at least partially remove additional amounts of said purge gas from said condensed portion as a gaseous flash stream, thereby creating a more-enriched monomer product stream;(d) membrane treating said uncondensed portion in a membrane separation unit, to further divide said uncondensed portion into a more-enriched purge gas stream and a mixed stream;(e) returning said mixed stream to said purge stream upstream of said partial condensation.