Comparison of ethylene polymerization in gas-phase and slurry reactors

This comparative study of ethylene polymerization in gas-phase and slurry reactors, using both a high-activity silica-supported TiCl sub 4 catalyst and a delta -TiCl sub 3 catalyst, showed that catalytic activities and molecular weights of products can be reactor dependent. The high-activity catalyst deactivated much faster in the gas-phase reactor than in the slurry reactor. The difference in the deactivation rates was so large that the rate of polymerization increased with increasing temperature for the slurry reactor whereas it decreased for the gas-phase reactor. Differences in the average molecular weights of the products from the two types of reactors were also observed. Thus, the results of slurry-reactor tests of deactivating catalysts are not necessarily transferrable to gas-phase operation. In contrast, the delta TiCl sub 3 catalyst had a time-invariant activity. However, the normalized activities were only independent of solvent and reactor type when based on the ethylene concentrations in the solvent for the slurry reactor and in the gas phase for the gas-phase reactor. This illustrates that the proper monomer concentration has to be used when comparing activities from gas-phase and slurry reactors. Graphs. 19 ref.--AA