Process for polymerizing monomers in fluidized beds
AssigneeExxon Chemical Patents Inc.
InventorsJohn R. Griffin, Marc L. DeChellis
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.
Claims87
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 process comprising employing in the fluidizing medium a level of liquid entering the reactor which is greater than 17.4 to 50 weight percent based on the total weight of the fluidizing medium and wherein the bulk density function (Z) is maintained at a value equal to or greater than the calculated limit of the bulk density function.
A process for polymerizing alpha-olefin(s) in a gas phase reactor having a fluidized bed and a fluidizing medium to produce a polymer product having a density in the range of 0.90 g/cc to about 0.939 g/cc, said process comprising operating said reactor such that the enthalpy change of said fluidizing medium entering and exiting the reactor is greater than 42 Btu/lb to about 110 Btu/lb and wherein the bulk density function (Z) is maintained at a value equal to or greater than the calculated limit of the bulk density function and wherein the polymer product is withdrawn at a rate above 500 lb/hr-ft.sup.2.
A process for polymerizing alpha-olefin(s) in a gas phase reactor having a fluidized bed and a fluidizing medium having a gas phase and a liquid phase entering the reactor, said process comprising:
- a) controlling the cooling capacity of said fluidizing medium by controlling the ratio of said gas phase to said liquid phase wherein the liquid phase comprises a level of liquid greater than 17.4 to 50 weight percent based on the total weight of the fluidizing medium;
- and
- b) maintaining the bulk density function (Z) at a value greater than or equal to the calculated limit of the bulk density function.
A continuous process for increasing reactor productivity of a gas phase polymerization reactor having a fluidizing medium and 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 and a gas phase, and recycling said fluidizing medium to said reactor, the process comprising:
- a) introducing said hydrocarbon into said fluidizing medium to permit an increase in the cooling capacity of the fluidizing medium above 42 Btu/lb to 110 Btu/lb;
- b) increasing the rate of withdrawal of polymer product to above at least about 500 lb/hr-ft.sup.2 ;
- c) calculating a bulk density function limit;
- and
- d) maintaining a bulk density function (Z) value greater than or equal to the calculated limit of the bulk density function.
A process or polymerizing alpha-olefin(s) in a gas phase reactor having a fluidized bed and a fluidizing medium for producing a polymer product having a density greater than about 0.940 g/cc, the processing comprising operating said reactor such that the enthalpy change of said fluidizing medium entering and exiting the reactor is greater than 67 Btu/lb to 110 Btu/lb and wherein the bulk density function (Z) is maintained at a value equal to or greater than the calculated limit of the bulk density function.
A process for polymerizing alpha-olefin(s) in a gas phase reactor having a fluidizing bed and a fluidizing medium having a gas phase and a liquid phase entering the reactor, said process comprising:
- a) controlling the cooling capacity of said fluidizing medium by controlling the ratio of said gas phase to said liquid phase wherein the liquid phase comprises a level of liquid greater than 17.4 to 50 weight percent based on the total weight of the fluidizing medium;
- b) calculating a bulk density function limit;
- c) monitoring a bulk density function (Z);
- and
- d) adjusting the bulk density function (Z) to maintain the bulk density function (Z) at a value greater than or equal to the calculated bulk density function limit.
Dependencies are inferred from the claim text.