Exxonmobil Chemical Patents Inc.

Exxonmobil Engineering & Technology Company

Kevin Wayne Lawson

Prasadarao Meka

Gabor Kiss

Jay L Reimers

Lawrence Carl Smith

Todd S Edwards

Peijun Jiang

Robert Tan Li

Christopher Garland Bauch

Blu E Englehorn

Aspy Keki Mehta

Keith W Trapp

Rodney S Smith

Daniel L Bilbao

Randell Wayne Dickey

Brett A Smith

Jason M Reverendo

John D Hedengren

This invention relates to a polymerization process for forming polymer comprising: contacting (typically in a solution or slurry phase), a monomer and a catalyst system in a reaction zone comprising at least one spiral heat exchanger and recovering polymer, wherein the monomer, the catalyst system and the polymer flow through the at least one spiral heat exchanger in a cross-flow direction relative to spirals of the at least one spiral heat exchanger.

Polymerization using a spiral heat exchanger

A fluidized reactor system includes a reactor containing a fluidized bed situated above a distributor plate arranged within the reactor, a fluidizing gas fed into the fluidized bed via the distributor plate to cause uniform fluidization of the fluidized bed and promote creation of solid polymeric granules, and a valve assembly penetrating a sidewall of the reactor to remove a mixture of the fluidizing gas and the solid polymeric granules from the fluidized bed. The valve assembly is coupled to the sidewall at a downward angle relative to the sidewall such that an upward-facing opening of the valve assembly extends into the fluidized bed.

Fluidized bed reactor systems

Methods for separating gaseous components, such as unreacted hydrocarbon monomer and/or solvent, from polyolefin solids are provided. The methods include flowing a first stream including polyolefin solids and gaseous unreacted hydrocarbon monomer and/or solvent through a portion of a gas-solid separation vessel having a volume sufficient so that polyolefin solids present in the first stream have an increased residence time within the gas-solid separation vessel to separate gaseous unreacted hydrocarbon monomer and/or solvent from the polyolefin solids to produce a second stream including polyolefin solids substantially free of gaseous unreacted hydrocarbon monomer and/or solvent and a third stream including the gaseous unreacted hydrocarbon monomer and/or solvent. Systems for carrying out such methods are also provided.

Methods of polyolefin solids recovery

Methods for separating gaseous components, such as unreacted hydrocarbon monomer and/or solvent, from polyolefin solids are provided. The methods include contacting a first stream including polyolefin solids and gaseous unreacted hydrocarbon monomer and/or solvent with a first purge gas in a gas-solid separation vessel to separate the gaseous unreacted hydrocarbon monomer and/or solvent from the polyolefin solids to produce a second stream including polyolefin solids substantially free of gaseous unreacted hydrocarbon monomer and/or solvent and a third stream including the gaseous unreacted hydrocarbon monomer and/or solvent. The first purge gas includes hydrocarbon monomer and/or solvent and has a temperature of at least about 70&#xb0; C. when entering the gas-solid separation vessel. Systems for carrying out such methods are also provided.

A process for reducing the level of hydrogen in certain polymerization effluent and recycle streams containing unreacted propylene monomers and hydrogen by contacting the streams with a hydrogenation catalyst so as to convert at least part of the propylene to the corresponding alkane. The process is particularly applicable to the effluent from a slurry polymerization reactor which has been used to produce a polypropylene homopolymer or copolymer having a first molecular weight and at least part of the effluent is to be supplied to a slurry polymerization reactor to produce a polypropylene homopolymer or copolymer having a second, higher molecular weight.

Olefin polymerization processes

A method for controlling the temperature of the inner surface of a transfer line dryer, and thus controlling the temperature of a polymer product flowing through the transfer line dryer, is explained. Also provided is a transfer line dryer apparatus that is useful for implementing the disclosed method.

Process for drying polymers

Disclosed is a method of reducing and/or regulating the level of hydrogen in a polymerization reactor comprising contacting a first feed comprising a first amount of hydrogen with a hydrogenation catalyst prior to entering a polymerization reactor to form a second feed; then contacting the second feed having a second amount of hydrogen with monomers and a polymerization catalyst in a polymerization reactor to form a polymer. The first and second feeds may reside in a feed line from one reactor to another, a monomer feed line to the reactor, or in a recycle line to and from the same reactor.

Method of regulating hydrogen to a polymerization reactor

A method is provided for polymerizing an olefin monomer in a reactor with a highly active polyolefin polymerization catalyst system. The method includes introducing a catalyst system comprising a catalyst and a catalyst activator into the reactor containing the olefin monomer with less than 10 seconds or no pre-contacting time of the catalyst and the catalyst activator prior to introducing the catalyst and the catalyst activator into the reactor. The catalyst system may have a standard adjusted catalyst activity of greater than 10 gPgcathr.

Methods for polyolefin polymerization with high activity catalyst systems

Disclosed herein are methods for controlling bubble formation in a polymerization reactor. The method includes: (a) determining a concentration of at least one component at a location in the reactor using a mathematical model; (b) determining a vapor pressure of the composition based at least in part upon the concentration of the component; (c) determining an operating pressure of the reactor at the location; (d) determining a pressure difference as &#x394;P=P&#x2212;P, wherein Pis the operating pressure and Pis the vapor pressure; (e) comparing the &#x394;P to a threshold value; and (f) implementing an effect when the &#x394;P is less than the threshold value.

Method for controlling bubble formation in polymerization reactors

Bubble formation is monitored in a reactor such as a loop polymerization reactor which effectively operates at pressures above or near the vapor pressure of a circulating slurry liquid. The method measures a property of the reactor composition at a first location within the reactor, and then at a second location within the reactor. The process is repeated, followed by determining if the difference in measured property varies from a reference difference, derived under bubble-free conditions. When the difference in measured physical property has changed relative to the reference difference, an effect may be implemented, e.g., increase of reactor pressure, decrease of composition vapor pressure, and decrease of reactor temperature, to an extent sufficient to reduce or eliminate bubbling.

System and method for monitoring bubble formation within a reactor

In a process for making a copolymer, a first product stream comprising a semi-crystalline polymer and a chain terminating agent is produced in a first reactor system. The first product is provided to a second reactor system wherein a low crystallinity polymer is produced in the presence of the semi-crystalline polymer. At least a portion of the chain terminating agent is removed from the second reactor system by an in-situ process.

Copolymer production system and process

Disclosed is a propylene impact copolymer comprising a first polypropylene having an MFRwithin the range from 15 to 40 dg/min; a second polypropylene having an MFRwithin the range from 50 to 190 dg/min; an elastomeric polymer; and wherein the propylene impact copolymer has an MFRwithin the range from 6 to 18 dg/min; a 1% Secant Flexural Modulus of greater than 150 kpsi (1030 MPa); and an Izod Impact at 25&#xb0; C. of greater than 10 ft-lbs/in (530 J/m). The impact copolymer may be produced in a two or three tandem-reactor system wherein the catalyst composition used in the second reactor to produce the second polypropylene is different from the catalyst composition used in the first reactor to produce the first polypropylene.

Growing community of inventors

Houston, TX, United States of America

Kevin Wayne Lawson