Chevron Phillips Chemical Company LP

Jeffrey S Lowell

Kenneth A Dooley

Joseph A Curren

Scott E Kufeld

Joel A Mutchler

Eric J Netemeyer

Jeffrey S Fodor

Ralph J Price

Michael H Treptau

Gregory G Hendrickson

Max P McDaniel

Eric D Schwerdtfeger

Daniel M Hasenberg

Rebecca A Gonzales

Darius Aruho

Ran Li

Eric A Ross

Kyle H Leger

Tess E Stecklein

Purnik Amin

Supported chromium (VI) catalysts containing a solid oxide, 0.05 to 5 wt. % chromium, and 0.2 to 20 wt. % carbon, in which the solid oxide or the catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a fluidized bed reactor or other suitable polymerization reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm, from 150 to 680 ppm solid oxide (such as silica), from 0.5 to 3 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ftof 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm (in diameter) per five grams of the ethylene polymer.

Particle size control of silyl chromate catalysts and uses thereof in fluidized bed reactors

Polymerization processes and reactor systems for producing multimodal ethylene polymers are disclosed in which at least one loop reactor and at least one fluidized bed reactor are utilized. Configurations include a loop reactor in series with a fluidized bed reactor and two loop reactors in series with a fluidized bed reactor.

Ethylene polymerization processes and reactor systems for the production of multimodal polymers using combinations of a loop reactor and a fluidized bed reactor

A purge system for a polymerization system may include a purge column including a stripping zone and a stripping fluid distributor below the stripping zone for injecting a stripping fluid including one or more light olefins. A first displacement zone is below the distributor. A second displacement zone is below the first displacement zone. A nitrogen distributor introduces nitrogen in the second displacement zone. Another purge system for a polymerization system may include a fluidized bed separator and a purge column. The fluidized bed separator includes a separator inlet, a stripping fluid inlet, a first stripped fluid outlet, and a separator outlet. The purge column includes a flake inlet, a stripping zone, a stripping fluid distributor below the stripping zone, a stripped flake outlet, and a second stripped fluid outlet for a second stripped fluid from the purge column.

Systems and techniques for polymer degassing

Techniques and systems for reducing fouling in a polymerization system are described. The polymerization system includes a reactor coupled to a recycle system. The recycle system includes at least one fouling-susceptible unit. The technique includes inducing polymerization of a reactant, for example, at least one olefin monomer reactant, with a catalyst in the reactor. The technique may further include circulating a fluidizing stream through the reactor and the at least one fouling-susceptible unit. The fluidizing stream may include entrained particles tending to foul the at least one fouling-susceptible unit. The technique can further include contacting the fluidizing stream with a catalyst poison at at least one location upstream of the at least one fouling-susceptible unit in the recycle system.

Systems and methods for mitigating polymer fouling

Methods of reducing heat exchanger fouling rate or of producing polyolefins may include providing a first gas stream comprising a gas and entrained fine polyolefin particles to a gas outlet line; removing a portion of the entrained fine polyolefin particles from the gas outlet line to form a bypass stream; and providing the bypass stream to a bypass line comprising a bypass line inlet and a bypass line outlet. The bypass line inlet and outlet are located upstream and downstream of a first heat exchanger. The methods may further include providing at least a portion of the first gas stream to the first heat exchanger; and combining the bypass stream and a second gas stream at the bypass line outlet to form a combined gas stream comprising one or more olefins or paraffins. A temperature of the combined gas stream is below the dew point of the combined gas stream.

Systems and methods for reducing heat exchanger fouling rate

The present invention discloses methods for removing volatile components from an ethylene polymer effluent stream from a polymerization reactor, and related polyethylene recovery and volatile removal systems. In these methods and systems, the polymer solids temperature is increased significantly prior to introduction of the polymer solids into a purge column for the final stripping of volatile components from the polymer solids.

Systems and methods for polyethylene recovery with low volatile content

Systems and methods for improved degassing of polymer flake are provided herein. These systems include a polymerization reactor configured to polymerize one or more olefin monomers and produce a product stream comprising solid polymer flake entrained in a fluid; a flash chamber configured to separate the solid polymer flake from the fluid and to produce a fluid stream and a concentrated stream; and a first degassing chamber configured to separate the concentrated stream by contacting the concentrated stream with a purge fluid comprising one or more light hydrocarbons to produce a partially degassed polymer flake stream and a purge fluid stream.

Polymer flake degassing system and methods

This disclosure provides for polymerization processes of polyolefins wherein the melt index can be regulated. For example, there is provided a process for producing a polyethylene, the process comprising: (1) in a polymerization reactor, contacting (a) a polymerization catalyst, (b) ethylene, (c) an optional &#x3b1;-olefin comonomer, and (d) (x+y) ppm by weight of an antistatic agent on an ethylene basis; and (2) applying reaction conditions to the reaction mixture suitable to produce the polyethylene having a desired set of characteristics, such as desired target melt index. The disclosed polymerization processes allow for production of polyolefins having higher melt indices, and in the alternative to produce polyolefins having a desired target melt index at lower polymerization temperatures.

Melt flow index response in polyethylene reactors

Systems and methods of reducing heat exchanger fouling rate and of producing polyolefins are provide herein. In some aspects, the methods include providing a first gas stream comprising a gas and entrained fine polyolefin particles to a gas outlet line; preferentially removing a portion of the entrained fine polyolefin particles from the gas outlet line to form a bypass stream comprising a higher concentration of the entrained fine polyolefin particles than is present in the first gas stream; providing the bypass stream to a bypass line comprising a bypass line inlet and a bypass line outlet, wherein the bypass line inlet is located upstream of a first heat exchanger, and wherein the bypass line outlet is located downstream of the first heat exchanger; providing at least a portion of the first gas stream to the first heat exchanger, which produces a first cooled gas stream; and combining the bypass stream and a second gas stream at the bypass line outlet to form a combined gas stream comprising one or more olefins or paraffins, wherein a temperature of the combined gas stream is below the dew point of the combined gas stream.

An eductor, a process and apparatus for gas phase polymerization of olefins in a polymerization reactor are disclosed. The process and apparatus employ an eductor which has an inlet which makes a bend of less than about 90&#xb0; toward the outlet after entering the mixing chamber of the eductor.

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Huffman, TX, United States of America

Jeffrey S Lowell