A METHOD FOR PREPARING POLYPROPYLENE BY POLYMERIZING PROPYLENE

摘要

PURPOSE:To perform polymerization at a constant temperature, by performing polymerization in the presence of a volatile solvent, condensing the formed vapor in a condenser, returning the condensate and part of noncondensible gas to the polymerization tank and at the same time regulating the temperature in the condenser and the amount of noncondensible gas recirculated. CONSTITUTION:A monomer is polymerized in the presence of a volatile liquid medium in a polymerization tank 1 and the formed vapor is condensed in a condenser 2, separated frm noncondensible gas, and returned to the polymerization tank 1 to remove the heat of polymerization and to control the polymerization temperature. The pressure of noncondensible gas remaining uncondensed is increased by a blower 3 and part of it is returned through a flow rate control valve 10 to the polymerization tank 1 to control the polymerization temperature, while the remaining part is recirculated through a flow rate control valve 11 and a line 5 to a line 15. The flow rate control valves 10 and 11 are regulated by a controller 13 according to the temperature in the polymerization tank 1 and at the same time a flow rate control valve 14 for regulating a flow rate of a coolant fed to the condenser 2 to control the polymerization temperature in good accracy.