Univation Technologies, LLC

Other

William Albert Matthews

Mark Gregory Goode

Francois Alexandre

Kevin Joseph Cann

John H Moorhouse

Timothy R Lynn

Cliff Robert Mure

Kefu Sun

George W Schwarz, Jr

Gerardo Corona

Dung P Le

Barbara J Kopp

Charles D Lester

Michael I Hurdle

Semra Gercek

Samuel Bernal

Richard B Pannell

Kiu H Lee

Fathi David Hussein

John Roberts Parrish

R Eric Pequeno

Ping P Cai

Brian Drake Bennett

Ivan Jeremy Hartley

Brandon C Locklear

Paul Kevin Samples

Francis C Zeigler

Rich John Stolz

John H Moorehouse

Susan D Broz

Embodiments of the present disclosure are directed towards method for modifying a polymer flow index. As an example, a method for modifying a polymer flow index can include providing monomers to a polymerization reactor, providing a chromium catalyst to the polymerization reactor, and providing an active amount of a flow index modifier to the polymerization reactor, wherein the flow index modifier is selected from carbon dioxide, carbon monoxide, 2,4-hexadiene, and combinations thereof.

Polymer flow index modifier

The present disclosure provides for a system and method for producing a polyethylene polymer (PE) that includes measuring a melt flow index (MFI) of the PE, comparing the measured value of the MFI to a predetermined desired range for the MFI, changing a catalyst feed rate to the polymerization reactor based on the compared values of the MFI, where changes in the catalyst feed rate preemptively compensate for subsequent changes in an oxygen flow rate to the polymerization reactor that maintain a predetermined residence time and bring the MFI of the PE into the predetermined desired range for the MFI; and changing the oxygen flow rate to the polymerization reactor thereby maintaining both the predetermined residence time and bringing the MFI of the PE into the predetermined desired range for the MFI. The measuring and comparing steps are repeated to ensure the measured value of the MFI is within the predetermined desired range of the MFI at the predetermined residence time.

Producing a polyethylene polymer

Disclosed herein are methods of controlling polymer properties in polymerization processes that use a chromium-based catalyst. An embodiment discloses a method of producing a polyolefin comprising: contacting a reaction mixture and a reduced chromium oxide catalyst in a gas-phase reactor to produce the polyolefin, wherein the reaction mixture comprises a monomer and a co-monomer; and changing a reaction temperature in the gas-phase reactor by about 1&#xb0; C. or more whereby a gas molar ratio of the co-monomer to the monomer is changed by about 2% or more and a co-monomer content of the polyolefin at substantially constant density is changed by about 2% or more. Additional methods and compositions are also provided.

Methods for controlling polymer properties

A method for transitioning a gas phase polymerization reactor between metallocene catalysts is provided. The method comprises first reducing the superficial gas velocity and increasing the height of the fluidized bed within the reactor prior to stopping a feed comprising a first metallocene catalyst. The method further comprises introducing a first polymerization neutralizer to the reactor, wherein the first polymerization reactor does not comprise water, and then introducing a second polymerization neutralizer to the reactor, wherein the second polymerization neutralizer is different from the first polymerization neutralizer. After this, the method comprises purging the reactor with an inert gas and then introducing a feed comprising a second metallocene catalyst to the reactor.

Closed reactor transitions between metallocene catalysts

Catalyst feed systems and processes utilizing such systems are described herein. Some embodiments disclosed herein relate to a process for improving the flowability of catalyst in a catalyst feed system, including providing a catalyst feed vessel with at least one heat exchange system for maintaining the catalyst system temperature below a critical flow temperature. Also disclosed is a catalyst feed system for the polymerization of olefins including a catalyst feed vessel; and a heat exchange system for maintaining a temperature of a catalyst within the catalyst feed vessel. Additionally disclosed is a process for polymerization of olefins including maintaining a supported catalyst in a catalyst feed vessel below a critical flow temperature of the catalyst; feeding the catalyst to a polymerization reactor; and contacting the catalyst with an olefin to form a polyolefin.

Catalyst feed systems and methods for using the same

Sheet material lifts including an elongate body extending along a longitudinal axis between a first end and a second end, a foot extending transverse the longitudinal axis from the second end of the elongate body, a support element disposed on the foot distal the elongate body, a base defining a fulcrum coupled to the foot, and an arm extending transverse the longitudinal axis from the elongate body at a position intermediate the first end and the second end. In some examples, the arm includes a sleeve, and a shaft slidingly mounted within the sleeve, the shaft being configured to slide along a path between a retracted position proximate the elongate body and an extended position distal the elongate body.

Sheet material lifts

A process for increasing a granular particle density of a polymeric product using at least one particle density promoting agent is described. The process includes passing a gaseous stream comprising at least one monomer through a fluidized bed reactor in the presence of a catalyst to form a polymeric product having a first granular particle density of less than or equal to about 850 kg/m, contacting the polymeric product with at least one particle density promoting agent to increase the granular particle density of the polymeric product by at least 2%, withdrawing the polymeric product having an increased granular particle density and a recycle stream comprised of unreacted monomers, and cooling and reintroducing the recycle stream into the fluidized bed reactor with sufficient additional monomer to replace the monomer polymerized and withdrawn as the polymeric product.

Gas-phase polymerization process to achieve a high particle density

Agonist antibodies are disclosed which bind to the extracellular domain of the flk2/flt3 receptor and thereby activate the intracellular kinase domain thereof. The labeled antibodies are useful as diagnostics for detecting the presence of the flk2/flt3 receptor in primitive hematopoietic cells for example. The antibodies are able to cause primitive hematopoietic cells to proliferate and/or differentiate and thereby enhance repopulation of mature blood cell lineages in a mammal which has undergone chemo- or radiation therapy or bone marrow transplantation. The antibodies are further useful for treating mammals which have suffered a decrease in blood cells as a consequence of disease or a hemorrhage, for example.

Agonist antibodies against the flk2/flt3 receptor and uses thereof

A continuous process for the polymerization of one or more alpha-olefins in the gas phase in the presence of a chromium based catalyst, under polymerization conditions including the reaction temperature, the pressure, and the target oxygen to alpha-olefin molar ratio operating point required for desired resin properties.

Process control in the presence of chromium based catalysts

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Hilton Head Island, SC, United States of America

William Albert Matthews