Process for polymerizing monomers in fluidized beds
AssigneeExxon Chemical Patents Inc.
InventorsMarc L. DeChellis, John R. Griffin
Life of this patent
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Abstract
The invention is directed toward polymerizing or copolymerizing alpha-olefins either alone or in combination with one or more other alpha-olefins in a gas phase reactor having a fluidized bed and a fluidizing medium such that the fluidizing medium entering the reactor comprises a gas and a liquid phase.
Claims43
A process for polymerizing alpha-olefin(s) in a gas phase reactor having a fluidized bed and a fluidizing medium wherein the fluidizing medium serves to control the cooling capacity of said reactor, the improvement comprising employing a level of liquid in the fluidizing medium entering the reactor which is in the range of from 17.4 to 50 weight percent based on the total weight of the fluidizing medium and maintaining the ratio of fluidized bulk density to settled bulk density above 0.59.
A process for polymerizing alphaoolefin(s) in a gas phase reactor having a fluidized bed and a fluidizing medium for producing film and molding grade products, the improvement comprising operating said reactor such that the enthalpy change of said fluidizing medium entering and exiting the reactor is in the range of from 42 Btu/lb to 110 Btu/lb and maintaining the ratio of fluidized bulk density to settled bulk density above 0.59.
A continuous process for increasing reactor productivity of a gas phase polymerization reactor having a fluidizing medium and a fluidized bed, said process comprising passing a gaseous stream comprising monomer through a reaction zone in the presence of a catalyst to produce a polymeric product, withdrawing said polymeric product, withdrawing said fluidizing medium comprising unreacted monomer from said reaction zone, mixing said fluidizing medium with hydrocarbon and polymerizable monomer(s) to form a liquid phase and a gas phase, and recycling said fluidizing medium to said reactor, the improvement comprising:
- a) introducing said hydrocarbon into said fluidizing medium to permit an increase in the cooling capacity of the fluidizing medium to a level in the range of from 42 Btu/lb to 110 Btu/lb;
- b) increasing the rate of withdrawal of polymer product to above 500 lb/hr-ft.sup.2 ;
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- c) maintaining the ratio of fluidized bulk density to settled bulk density above 0.59.
Dependencies are inferred from the claim text.