Polymerization processes loop reactor/circulation

Slurry phase (or suspension) process. The uniquedooldng equipment in Figure 23—5 is a loop reactor. This process also takes place in a solvent (in this case, normal hexane, isobutane, or isopentane) so that the mixture can be pumped continuously in a loop while the polymerization is taking place. Feeds (the solvent, comonomer if any, ethylene and Ziegler-Natta catalyst) are pumped into the loop and circulated. Polymerization rakes place continuously at temperatures below the melting point of the polyethylene allowing solid polymer particles to form enough to form slurry. The reaction takes place at 185—212°F and 75—150 psi. A slurry of HOPE in hexane is drawn off continuously or intermittently. 

Description The Spherizone process is Basell s new proprietary gas-loop reactor technology based on a Multi-Zone Circulating Reactor (MZCR) concept. Inside the reactor (1) the growing polymeric granule is continuously recirculating between two interrelated zones, where two distinct and different fluodynamic regimes are realized. 

Insoluble initiator and polymer With a polymerizing system of ethylene and an agitated catalyst suspension at lower temperatures, polyethylene and catalyst may be insoluble in an inert diluent and form a slurry that is removed continuously. The loop (or double-loop) reactor developed by Norwood [15] has been widely used for the slurry process. Turbulent circulation in... 

Table I provides an overview of general reactor designs used with PS and HIPS processes on the basis of reactor function. The polymer concentrations characterizing the mass polymerizations are approximate there could be some overlapping of agitator types with solids level beyond that shown in the tcd>le. Polymer concentration limits on HIPS will be lower because of increased viscosity. There are also additional applications. Tubular reactors, for example, in effect, often exist as the transfer lines between reactors and in external circulating loops associated with continuous reactors.

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