Method for the heat removal from polymerization reactor

Claim 1

In a method of the heat removal from a polymerization reactor with a reflux condenser, wherein an unsaturated hydrocarbon monomer having 2 to 8 carbon atoms is polymerized in an inert hydrocarbon or in the liquefied monomer having 3 to 8 carbon atoms as a solvent, in the presence of an olefin polymerization catalyst, by introducing a gas mixture withdrawn from the polymerization reactor into the reflux condenser where the gas mixture is condensed and separated into a condensed liquid and an uncondensed gas and returning the condensed liquid to the polymerization reactor and the uncondensed gas into the liquid phase in the polymerization reactor by the use of a compressor, the improvement comprising washing the gas mixture by bringing it into countercurrent contact with at least one of the condensed liquid obtained in the reflux condenser and the solvent to be supplied to the polymerization reactor, after it leaves the polymerization reactor and before it reaches the heat transfer surface of the reflux condenser.