The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 29, 2002
Filed:
Apr. 04, 2001
Kaspar Evertz, Schifferstadt, DE;
Manfred Sandkühler, Grünstadt, DE;
Walter Schicketanz, Frankenthal, DE;
Basell Polyolefine GmbH, Kehl, DE;
Abstract
Polyolefins, preferably polyethylene, are prepared in a continuous gas-phase polymerization process in which the fluid monomeric component, preferably ethylene, and, optionally, one or more comonomers is/are polymerized in the polymerization zone of a fluidized-bed reactor in the presence of one or more catalysts, optionally with the addition of various auxiliaries, under reaction conditions where the fluidizing gas is circulated to remove the heat of polymerization or reaction and the polymerization product is taken from the circuit and the corresponding amount of monomer and, optionally, comonomers and optionally further auxiliaries are fed in, wherein the fluidizing gas discharged from the fluidized-bed reactor is cooled by means of a direct cooling apparatus in which the coolant is brought into direct contact with the fluidizing gas and heated coolant is passed to at least one further cooling stage in order to cool it and is, after cooling, wholly or partly returned to the direct cooling apparatus and/or heated or cooled coolant is wholly or partly returned to the reactor.