Patent ID: 9422381
Filing Date: 2016-08-23
CPC Classification: C08F,Y02P

Claim Text:
1. A method of olefin polymerization comprising: feeding a circulating gas including at least one alpha-olefin and an inert gas into a reactor; polymerizing the alpha-olefin into a polyolefin in a reaction region in the reactor; and discharging the polyolefin from the reactor, wherein the reactor comprises a cylindrical base section a positioned in the lower part thereof and a conical top section b positioned on the top of the cylindrical base section and having an open top and a boundary between the cylindrical base section a and the conical top section b, wherein the conical top section b has an angle of inclination in the range of 4° to 7° with respect to a perpendicular line, wherein the inside of the reactor is divided into a reaction region A that is a fluidized bed region having an olefin polymerization occurring therein, and a free region B positioned on the top of the reaction region A and having solid polyolefin particles separated from the gas phase, wherein the fluidized bed A is at least as high as the cylindrical base section a and 80 percent or less the height of the conical top section b; wherein a draft tube is provided in the fluidized bed A, so the circulating gas and polyolefin particles are discharged from the top of the draft tube to the fluidized bed A from a discharging portion of the draft tube positioned at the boundary between the cylindrical base section a and the conical top section b.