método de polimerização de olefina

Disclosed is a method of olefin polymerization that enables production of polyolefin with high productivity while suppressing sheeting or caking in the reactor. The method of olefin polymerization includes: 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, which reactor consists of 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. The conical top section b has an angle of inclination in the range of 4° to 7° with respect to a perpendicular line. 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. The fluidized bed is at least as high as the cylindrical base section a and 80 percent or less the height of the conical top section b.