Dry chlorination of PVC at specified temp. with irradiation - in 14-chamber fluid-bed reactor with specified residence time, back-mixing ratio and temp. for each chamber

摘要

Process is for the dry chlorination of PVC in a multi-chamber fluid-bed reactor at 55-100 deg. C with a reaction gas contg. 0.18-0.66 kg Cl/kg gas and a radiation dose of 10-30 krad/hr. The PVC is chlorinated in a 14-chamber reactor with residence times as follows: (a) in chamber 1, 30-45 mins., in chambers 2, 3 and 4, residence times in the ratio 0.7:0.4:0.4 w.r.t. 1.0 in chamber 1, (b) in chambers 5-3, the same residence times as in chamber 4, (c) in chambers 9-13, a residence time which is in the ratio 1:0.3 w.r.t. that in chamber 1, and (d) in chamber 14 a residence time which is in the ratio 1:0.35 w.r.t. that in chamber 1; the degree of back-mixing established in the various chambers, as expressed by the ratio between the ratio of reaction mass to mass throughput and the ratio of the area of apertures to the area of chamber partitions in the height of the fluid bed, is 200-1200 in chambers 1-8 and 1200-2000 in chambers 9-13. USE/ADVANTAGE - The process is useful for the prodn. of PVC-C contg. 64-69 wt.% Cl; the invention provides a simplified continuous process for the prodn. of PVC-C with high thermal stability and a narrow range of Cl distribution, without sintering of the PVC-C particl