Patent ID: 6069212
Filing Date: 2000-05-30
Classification: B01J,C08F,Y02P

Abstract:
A process for continuous vapor phase polymerization of a polymerizable monomer or mixture thereof to produce normally solid polymer in two or more serially disposed vapor phase polymerization reactors, each containing a quench-cooled subfluidized particulate bed of polymerized monomer, whereby particles are transferred between high pressure, reactive gas-filled, continuous, vapor-phase polymerization reactors while maintaining each reactor at independently selected operating conditions, which process comprises:(a) discharging a slug containing particles of forming polymer and reactive gases from an upstream reactor,(b) collecting the particles in a transfer chamber having side walls which are vertical and/or inclined toward a bottom discharge port at an angle of less than about 20.degree. from vertical, while maintaining the pressure therein at least 5 psi below the operating pressure of the upstream reactor,(c) repeating steps (a) and (b) to detach a suitable mass of particles from the bed in the upstream reactor,(d) displacing a substantial portion of the reactive gases from the collected particles and the transfer chamber with a purge gas having a composition which is compatible with the independently selected operating conditions in each reactor, and different from the composition of reactive gases in the upstream reactor,(e) pressurizing the transfer chamber gas pressure to at least about 1 psi above the operating pressure of the downstream reactor to facilitate transfer of the particles from the transfer chamber into the downstream reactor, and(f) discharging the particles from the transfer chamber into the downstream reactor;wherein the transfer of polymer particles is carried out using dual transfer chambers operated in alternating sequences.