| 摘要 |
1,068,708. Purification of vinyl chloride by distillation. INSTITUT FUR CHEMIEANLAGEN. Aug. 6, 1965, No. 33796/65. Heading BIB. Crude vinyl chloride, especially that produced by reacting acetylene with hydrogen chloride, is purified by introducing the crude gaseous vinyl chloride, preferably at a pressure of 3 atm. abs., into a fractionating column 4 wherein the higher-boiling impurities are condensed and withdrawn from sump 5, compressing the gas leaving the head of the column to about 9 atm. abs. in compressor 6, condensing the compressed gas in condenser 9 by heat-exchange with water or air, submitting the condensate to distillation in fractionating column 12 to expel lower-boiling impurities (e.g. acetylene), and withdrawing purified liquid vinyl chloride from the sump 15 of the column. Column 12 is preferably operated at a pressure of 2 to 3 atm. abs. The gas leaving dephlegmator 13 is returned to the acetylene/ hydrogen chloride reactor. As shown, the gas from compressor 6, before being condensed, is passed through saturator 7 in countercurrent to part of the condensate from condenser 9. The liquid leaving the base of saturator 7 is used as reflux for column 4; and the saturated gas leaving the top of the saturator is conducted via heat-exchanger 8 into condenser 9. The other part of the condensate from condenser 9 is cooled by heat-exchange with brine in cooler 10, and then introduced into column 11, where it contacts the residual vapours withdrawn from condenser 9. Part of the condensate withdrawn from the sump of column 11 is passed, together with the condensate from heat-exchanger 8, into column 12, which is heated by the crude feed gas supplied by compressor 2 to heat-exchanger 3. The remainder of the condensate from column 11 is expanded in evaporator 16, and some of the liquid is then conducted to heat-exchanger 17 where it cools the brine required for cooler 10 and dephlegmator 13. The remainder of the liquid withdrawn from evaporator 16 is pumped into the upper section of column 11. The condensate from heat-exchanger 3 is also used to cool the brine in heat-exchanger 17. The vapours leaving evaporator 16 and heat-exchanger 17 are conducted to compressor 2. |
