Exxonmobil Chemical Patents Inc.

Univation Technologies, LLC

Ryan Winston Impelman

Bruce Jon Savatsky

David F Sanders

Matthew William Holtcamp

John Francis Szul

Laughlin G McCullough

James McLeod Farley

Xuan Ye

Michael D Awe

Phuong Anh Cao

Charles J Harlan

Adriana S Silva

Maria A Apecetche

Ann M Schoeb-Wolters

Richard E Pequeno

Ching-Tai Lue

Matthew S Bedoya

Dongming Li

Joseph Moebus

Brian R Greenhalgh

Aaron C McGinnis

Anne A Bernard-brunel

Robert Olds Hagerty

Richard B Pannell

Eric John Markel

Rohan A Hule

Kevin A Stevens

Marc L DeChellis

David Jack Sandell

Hasnain Rangwalla

Arturo Leyva

Diwaker Singh

Luis A Sotomayor

Corrine L Brandl

Michael D Lucas

Anne Bernard-Brunel

Richard J Stolz

Matthew F Yott

Gerardo Corona

Cecile F Saladino

Rui Hoong Chong

Keng-Hua Beh

Joseph A Moebus

This disclosure relates to processes for producing polyolefins in a gas phase reactor using condensing agent(s) (CAs), and real-time calculation of the ratio of one type of CA to another CA within a CA composition. This disclosure provides methods for controlling condensed phase cooling in a gas phase reactor used to polymerize olefins. The polymerization may employ one or more polymerization catalysts to polymerize one or more olefin monomers, and may include introducing a first condensing agent and a second condensing agent in a ratio of first condensing agent to second condensing agent, which ratio is calculated by ascertaining a stick limit for a first condensing agent, calculating an equivalence factor relating the first condensing agent and a second condensing agent, ascertaining a total allowable condensing agent, and calculating a first amount of the first condensing agent removed and replaced by a second amount of the second condensing agent.

Methods for improving gas phase polymerization

The present disclosure relates to processes for production of polyolefins from olefin monomer(s) in a gas phase reactor using condensing agent(s) (CAs), and in particular relates to controlling condensed phase cooling in a gas phase reactor used to polymerize olefin monomer(s). The method may include introducing first and second condensing agent(s) into the reactor at ratio(s) determined by ascertaining a stick limit for the first condensing agent, calculating an equivalence factor relating the first and second condensing agents, ascertaining total allowable condensing agent, and calculating amount of the first condensing agent removed and replaced by the second condensing agent. The method may further include calculating the dew point limit of a gas phase composition including olefin monomer(s) as well as the first and second condensing agents; and determining if introducing a mixture comprising the olefin monomer(s) and the condensing agent composition would exceed the calculated dew point limit.

Methods for improving production in gas phase polymerization

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

Methods for scale-up from a pilot plant to full production of a bimodal polymer product having a density, melt index, and a melt index ratio are provided herein. The methods provide for adjusting reactor conditions and catalyst ratio of a bimodal catalyst system to optimize the transition from single catalyst to bimodal polymer compositions on a full-scale process plant consistent with pilot plant development.

Methods for scale-up from a pilot plant to a larger production facility

Methods for scale-up from a pilot plant to a larger production facility of a bimodal polymer product having a density, a melt index and melt index ratio are provided herein.

In a gas phase fluidized bed polymerization process for the production of polyolefin polymers, such as polyethylene polymers or polypropylene polymers, loss of ethylene or propylene accompanying inert gas purging is reduced by passing an ethylene- or propylene-containing purge stream through a vent column to contact a hydrocarbon liquid flowing through the vent column contercurrent to the purge stream whereby unreacted ethylene or propylene in the purge stream portion is dissolved in the hydrocarbon liquid to produce an ethylene- or propylene-enriched liquid stream and an ethylene- or propylene-depleted gaseous stream. The ethylene- or propylene-enriched liquid stream is then recycled to the fluidized bed reactor, while at least part of the ethylene- or propylene-depleted gaseous stream is purged.

Polymerization processes

Polyethylene compositions including at least 65 wt % ethylene derived units and from 0 to 35 wt % of C-Colefin comonomer derived units, based upon the total weight of the polyethylene composition are provided. The polyethylene compositions have a) an RCI,m of 100 kg/mol or greater and one or both of: b) a Tw-Twvalue of from &#x2212;16 to &#x2212;38&#xb0; C.; and c) an Mw/Mwvalue of at least 0.9. The polyethylene compositions may be used to manufacture articles such as films.

Polyethylene compositions and articles made therefrom

The present disclosure provides processes for polymerizing olefin(s). Methods can include contacting a first composition and a second composition in a line to form a third composition. The first composition can include a contact product of a first catalyst, a second catalyst, a support, a first activator, a mineral oil. The second composition can include a contact product of an activator, a diluent, and the first catalyst or the second catalyst. Methods can include introducing the third composition from the line into a gas-phase fluidized bed reactor, introducing a condensing agent to the line and/or the reactor, exposing the third composition to polymerization conditions, and/or obtaining a polyolefin. Polyethylene compositions including at least 65 wt % ethylene derived units, based upon the total weight of the polyethylene composition, are provided.

Polymerization processes and polymers made therefrom

A method for cleaning a distributor plate in a fluidized bed polymerization reactor system according to one embodiment includes, in a first mode, operating with about a normal, baseline value of superficial gas velocity in a fluidized bed polymerization reactor system having a reactor vessel, a recycle line, and a distributor plate in the reactor vessel near an inlet of the reactor vessel. In a second mode, the superficial gas velocity is increased above the baseline value of the first mode to a level sufficient to raise the temperature of the cycle gas at the inlet above an average temperature of the cycle gas at the inlet in the first mode, and to a level sufficient to dislodge foulant from holes in the distributor plate.

Methods for cleaning the distributor plate in a fluidized bed reactor system

Methods are provided to prepare a catalyst system that includes at least one titanium compound, at least one magnesium compound, at least one electron donor compound, at least one activator compound, and at least one silica support material, the at least one silica support material having a median particle size in the range of from 20 to 50 microns with no more than 10% of the particles having a size less than 10 microns and no more than 10% of the particles having a size greater than 50 microns and average pore diameter of at least &#x2267;220 angstroms.

Methods to prepare catalyst compositions comprising small silica support materials

Improved catalyst compositions, and polymerization processes using such improved catalyst compositions, are provided. An example of an improved catalyst composition is a supported catalyst system that includes at least one titanium compound, at least one magnesium compound, at least one electron donor compound, at least one activator compound, and at least one silica support material, the at least one silica support material having a median particle size in the range of from 20 to 50 microns with no more than 10% of the particles having a size less than 10 microns and no more than 10% of the particles having a size greater than 50 microns and average pore diameter of at least &#x2267;220 angstroms.

Catalyst compositions comprising small silica support materials and methods of use in polymerization reactions

Improved catalyst compositions, and polymerization processes using such improved catalyst compositions, are provided. An example of an improved catalyst composition is a supported catalyst system that includes at least one titanium compound, at least one magnesium compound, at least one electron donor compound, at least one activator compound, and at least one silica support material, the at least one silica support material having a median particle size in the range of from 20 to 50 microns with no more than 10% of the particles having a size less than 10 microns and no more than 10% of the particles having a size greater than 50 microns and average pore diameter of at least &#x3c;220 angstroms.

A polyethylene film having a balance of improved physical and mechanical properties and a method for making the same are provided. In one aspect, the film includes a 1% secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil. In one aspect, the method comprises reacting ethylene derived units and a comonomer in the presence of a hafnium-based metallocene at a temperature of from 70&#xb0; C. and 90&#xb0; C., an ethylene partial pressure of from 120 psia and 260 psia, and a comonomer to ethylene ratio of from 0.01 to 0.02 to produce an ethylene based polymer. The method further comprises extruding the ethylene based polymer at conditions sufficient to produce a polyethylene film comprising a secant modulus of greater than 25,000 psi, a dart impact resistance of greater than 500 g/mil, and a MD tear strength of greater than 500 g/mil.

High tear films from hafnocene catalyzed polyethylenes

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Houston, TX, United States of America

Ryan Winston Impelman