Exxonmobil Chemical Patents Inc.

Corrine L Brandl

James Richardson Lattner

Harry William Deckman

Fred David Ehrman

Ryan Winston Impelman

William Anthony Lamberti

Marc L DeChellis

Joseph Moebus

Charles Raymond Buhler, Iv

Diwaker Singh

Michael D Lucas

Luis A Sotomayor

Judson Sid Clements

Anne Bernard-Brunel

Keng-Hua Beh

Rui Hoong Chong

Judson S Clements

Joseph A Moebus

Gas phase polymerization processes include contacting an input stream comprising a monomer and an induced condensing agent in the presence of an inert gas with a catalyst in a fluidized bed reactor to produce a polymer, unreacted monomer, and an output gas; recycling a recycle stream of the unreacted monomer from the reactor to the input stream; venting at least a portion of the output gas from the reactor; and maintaining a partial pressure of the inert gas in the reactor above a reference inert gas pressure to decrease losses of the recycle stream with the vented output gas. The processes may include controlling the inert gas partial pressure to vary the total reactor pressure up to the maximum safe pressure, without causing carry-over of product polymer.

Optimized inert gas partial pressure in a gas phase polymerization process

A process including contacting one or more monomers, at least one catalyst system, and at least two condensing agents under polymerizable conditions to produce a polyolefin polymer is provided where the vapor pressure of the condensing agents is &#xb1;4 bara of the optimum vapor pressure given by the formula: optimum vapor pressure=614&#x2212;716*D+2.338*P+3.603*ln(MI), where the optimum vapor pressure has units (bara), D is the polyolefin polymer density with units (g/cc), P is the polymerization condition pressure with units (barg), and MI is the polyolefin polymer melt index with units (g/10 min). The invention also relates to a process where at least three condensing agents are used.

Polymerization process

A process for producing polyethylene polymers including contacting ethylene and at least one Cto Calpha-olefin comonomer with a polymerization catalyst on a particulate support in a fluidized bed polymerization reactor under conditions effective to polymerize at least part of the ethylene and comonomer and produce the polyethylene polymers, wherein the support has a dparticle size as measured by laser diffraction of at least 18 microns, is provided.

Process for producing polyethylene polymers

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Beaumont, TX, United States of America

Corrine L Brandl