Patent ID: 6812301
Filing Date: 2004-11-02
Classification: B01J,C08F,Y10S

Abstract:
A method for producing homopolymers or copolymers of propylene by polymerization of suitable monomers by means of a catalyst at temperatures of 40 to 150Â° C. and pressures of 10 to 50 bar in the gas phase, in which the gaseous or liquid monomer is placed in a polymerization zone and the polymer is discharged from the polymerization zone, and in the polymerization zone the pressure and temperature are kept within a range which corresponds to the gaseous state of the monomers;gaseous monomers not consumed by polymerization are discharged from the polymerization zone, liquefied in a condenser, stored, and re-introduced in liquid form into the polymerization zone; the temperature in the polymerization zone is regulated by means of continuous measurement of the temperature and by means of a resultant change, caused upon a change in temperature, of the quantity introduced per unit of time of liquid monomers evaporated in the polymerization zone; and the monomers consumed by polymerization are replaced by delivering fresh monomer, which comprises measuring the temperature in the polymerization zone at a plurality of points offset vertically from one another, and forming a mean value from each of the respective measured values; comparing the mean values with computed set-point value specifications, and changing the quantities of monomers to be fed into the polymerization zone on the basis of the magnitude and sign of the difference ascertained; and keeping the pressure in the polymerization zone constant by regulating the level of liquefied monomers in the condenser by means of a compensation container for the condensed monomers carried in circulation.