Slurry phase polymerisation process
AssigneeIneos Manufacturing Belgium NV
InventorsStephen Kevin Lee, Daniel Marissa, Brent R. Walworth
Life of this patent
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Abstract
Process comprising polymerising in a loop reactor of a continuous tubular construction an olefin monomer optionally together with an olefin comonomer in the presence of a polymerisation catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent, wherein the average internal diameter of at least 50% of the total length of the continuous tubular loop reactor is at least 700 mm wherein the HMW polymer is produced in a reactor upstream of the LMW polymer reactor and the ratio of the average internal diameter of the HMW reactor to the average internal diameter of the LMW reactor is between 0.8 and 1.4.
Claims13
Process comprising polymerising in a loop reactor of a continuous tubular construction an olefin monomer optionally together with an olefin comonomer in the presence of a polymerisation catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent, wherein the average internal diameter of at least 50% of the total length of the continuous tubular loop reactor is at least 700 mm wherein the HMW polymer is produced in a reactor upstream of the LMW polymer reactor and the ratio of the average internal diameter of the HMW reactor to the average internal diameter of the LMW reactor is between 0.8 and 1.4.
Process according to any preceding claim, wherein greater than 70%, preferably greater than 85% of the total length of the continuous tubular loop reactor has an internal diameter at least 700 mm.
Process according to any preceding claim, wherein the Froude number is preferably maintained in at least one reactor of the multiple reactor system at or below 30, preferably between 1 and 20 and more preferably between 2 and 15.
Process according to any preceding claim, wherein the total pressure drop in the loop of the reactor is less than 1.3 bar, preferably less than 1 bar, and the polymer production rate is greater than 25 tonnes per hour, preferably greater than 45 tonnes per hour.
Process according to any preceding claim, wherein at least 30 wt %, preferably more than 40 wt %, of the total polymer produced in the multiple reactor system is made in said continuous tubular loop reactor.
Process according to any preceding claim, wherein the density span of the polymer powder particles (defined as the absolute value of the density difference in g/cm3 between the average density of the polymer particles exiting the reactor with particle size above D90 and the average density of the material with particle size below D10) is below 0.005, preferably below 0.003, more preferably below 0.0026, most preferably below 0.0023, in which D10 and D90 are the diameters under which 10% and 90% by weight respectively of the particles are collected.
Process according to any preceding claim, wherein the particle size distribution of the polymer particles is such that (D90−D10)/D50 is less than 2, preferably less than 1.5, more preferably less than 1.2, in which D10, D50 and D90 are the diameters under which 10%, 50% and 90% by weight respectively of the particles are collected.
Process according to any preceding claim, wherein D95 is less than 2000 μm, preferably less than 1500 μm, more preferably less than 1000 μm, most preferably less than 355 μm in which D95 is the diameter under which 95% by weight of the particles are collected.
Process according to any preceding claim, which comprises making a multimodal ethylene polymer in which a low molecular weight (LMW) polymer is made in one reactor, and a high molecular weight (HMW) polymer is made in another reactor, the polymers being made in either order and the second polymer being made in the presence of the first.
Dependencies are inferred from the claim text.