EP0952990A1 - Ralentissement temporaire d'une reaction de polymerisation - Google Patents

Ralentissement temporaire d'une reaction de polymerisation

Info

Publication number
EP0952990A1
EP0952990A1 EP98901780A EP98901780A EP0952990A1 EP 0952990 A1 EP0952990 A1 EP 0952990A1 EP 98901780 A EP98901780 A EP 98901780A EP 98901780 A EP98901780 A EP 98901780A EP 0952990 A1 EP0952990 A1 EP 0952990A1
Authority
EP
European Patent Office
Prior art keywords
catalyst
process according
reactor
idling
agent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP98901780A
Other languages
German (de)
English (en)
Inventor
Ui Sun An
Kenneth Alan Dooley
Brad Thedford Duckworth
Randal Ray Ford
Glenn Edward Moore
Dennis Olin Ramsey
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Chemical Co
Original Assignee
Eastman Chemical Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Chemical Co filed Critical Eastman Chemical Co
Publication of EP0952990A1 publication Critical patent/EP0952990A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/1809—Controlling processes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00628—Controlling the composition of the reactive mixture
    • B01J2208/00637—Means for stopping or slowing down the reaction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00245—Avoiding undesirable reactions or side-effects
    • B01J2219/00272—Addition of reaction inhibitor

Definitions

  • the present invention relates to a process for idling a polymerization reaction by addition of a catalyst deactivator.
  • polymers can be produced by olefin polymerization in a fluidized bed gas phase reactor.
  • a reaction gas mixture containing the olefin(s) being polymerized is passed upwardly through the reactor, and the newly formed polymer particles are kept in a fluidized state.
  • the gas mixture exits the top of the reactor and is recycled back to the bottom of the reactor by a compressor.
  • the heat absorbed by the gas mixture during polymerization is removed by heat exchangers.
  • Examples of a fluid bed polyolefin process are disclosed in U.S. Patent No. 4,882,400 and U.S. Patent No. 5,332,706. Numerous configurations and modifications are known.
  • reactor transitions present a problem.
  • Reactor transitions are scheduled discontinuous operations of the reactor.
  • a fluidized bed reactor undergoes transitions to change polymerization reaction conditions in order to produce different products with different properties.
  • the existing active catalyst sites in the reactor be deactivated. By deactivating the active catalyst sites, the production of transition material is reduced. Bringing the system back to full operation is very time consuming.
  • shutting down a reactor For instance, catalyst or reactant feed can be stopped. However, stopping the feeds to the reaction process will not stop polymerization immediately if all other process parameters, such as temperature, pressure, reactor gas composition, reactor gas velocity, etc., are held constant, since there is still active catalyst and reactants in the reactor. Such a deactivation can last for a considerable amount of time.
  • U.S. Pat No. 4,306,044 discloses a carbon dioxide kill system that is used to kill the active catalyst sites in the reactor by injecting carbon dioxide in amount five times the total effective catalyst system (on a molar basis; note, e.g., column 6, lines 47-49).
  • this method requires a significant amount of time to vent off excess poison gas and reestablish polymerization reaction conditions and fails to provide an economic solution.
  • U.S. Pat No. 4,834,947 discloses the introduction of a carbon oxide gas (CO and CO 2 ) and venting gas from the top of the reactor (note, e.g. , column 3, lines 14-19). This method also requires a significant amount of time to reestablish polymerization reaction conditions and requires the replacement of expensive hydrocarbons lost from venting the reactor.
  • CO and CO 2 carbon oxide gas
  • U.S. Pat. No. 5,270,408 discloses a kill method that also requires the replacement of expensive hydrocarbons lost from venting the reactor contents.
  • there are remedies that quickly kill the active catalyst sites in a reactor but suffer various drawbacks, such as they are too slow to deactivate the system, they are uneconomical because they lose reactor contents, and/or the require a significant amount of downtime to re-establish reactor conditions. Accordingly, there is a need to temporarily idle a reactor such that the reaction is suppressed while yet maintaining the polymerization reaction conditions in the reactor so that polymerization can commence when desired.
  • the process according to the present invention entails a method for temporarily idling a polymerization process by injecting into the reaction medium a predetermined amount of idling agent so that only catalyst sites currently active are deactivated and so that no free idling agent is present in the reactor. With the active catalyst sites deactivated, polymerization gas compositions, reactor temperature and pressure can be maintained at target conditions or be adjusted to greatly revised target conditions while polymerization is in idle mode. The reaction can then be immediately reestablished when desired, since the reaction gas composition, temperature, pressure, bed fluidization, etc., are controlled at target conditions.
  • the process is more particularly concerned with idling a fluidized gas phase reactor process.
  • Figure 1 shows one useful arrangement of a fluid bed polyolefin process.
  • an idling agent is added to the reactor to reduce the reaction rate very quickly or stop the reaction altogether by deactivating the catalyst and/or co-catalyst.
  • "Idling agent” as used herein means a catalyst poison, catalyst deactivator, or kill agent, as these latter three terms are per se known in the .art. The terms are used interchangeably herein unless otherwise specifically noted. More particularly, the idling agent is added to the process in a controlled fashion such that only catalyst sites currently active are deactivated. It is not necessary to alter any other process conditions, although it is preferred that fresh catalyst feed be either reduced or discontinued, depending on how long a downtime is desired. Reactor parameters can be adjusted in the case of a reactor transition. The invention has the advantages of allowing the reaction to be immediately re-established when desired since the reaction gas composition, temperature and pressure are controlled at target conditions while the polymerization is being held in idle mode.
  • the temporary idling of the reactor is obtained without modifying the normal polymerization reactor operating conditions.
  • temporary idling of the reactor or “temporary idling of the reaction” is meant that the reaction occurring in the reactor is slowed down to the extent necessary to cure a desired problem or for reactor transition, such as for the reasons discussed above in the introduction. In some cases it may be desirable to shut down the reaction only to a small extent, for instance only about 50% of the normal rate, but more preferably the reaction is shut down at least 85 % from the rate of normal production, even more preferably shut down 98% (i.e., to a rate 2% of the normal rate of production).
  • the reaction is shut down 100%, but it should be noted that at least one of the critical aspects of the present invention is that no more than 100 % of the idling agent needed is added, since what is desired is for the reaction to be re- established immediately when desired. The presence of excess idling agent will not permit this immediate re-establishment. Therefore, the present inventors have discovered that, as a practical matter to insure that no excess idling agent is add, the idling agent is added in less than the stoichiometric amount required to deactivate the active sites on the catalyst. In addition, the present inventors have found that, as a practical matter, generally absolute shut-down of the reactor is not necessary to cure the reactor problem or make the reactor transition. As mentioned, generally the reaction is idled to the extent of about 50% to 99% (i.e., the rate is now 50% to 1 % of the original rate).
  • the shut down can be achieved solely by addition of the idling agent and, in processes including continuous addition of fresh catalyst, stopping the addition of fresh catalyst.
  • the phrase "solely by addition of fresh catalyst" means that none of the other process parameters, e.g. , temperature and pressure, need to be changed.
  • it may be desirable to change such parameters e.g., in the case of reactor transitions.
  • the present process permits idling of the reactor by maintaining reactor pressure, bed fluidization, and without venting off the contents of the reactor.
  • the process according to the present invention permits a more efficient means of doing so, i.e., by idling the reactor.
  • the effective reduction of reaction achieved by the current invention varies depending on the fluidized bed level, the active catalyst concentration in the reactor, and the amount of idling agent added.
  • the reduction of reaction is from 50 % to about 99 % , preferably above 85 % and more preferably reaches 98%.
  • the reactor is shut down so that there is a substantial reduction of the reaction.
  • substantial reduction is meant less than 100 % shut-down, but enough to cure the problem or provide for reactor transitions. This compares with the complete shut down in other reactor kill methods, based on overwhelming the catalyst with kill agent or depressurizing, as discussed above.
  • the degree of polymerization reduction is observed by a low temperature differential of the gas over the inlet and outlet of the reactor 9 (referred to as "reactor bed temperature differential"), which in the present invention is approximately less than 3.6 °F (2 °C).
  • the amount of idling agent required to deactivate the active catalyst to the desired state of inactivity is based primarily on the amount of catalyst (and cocatalyst, if present), more specifically, the amount of active catalyst (e.g., transition metal in the case of a transition metal catalyzed polymerization) and cocatalyst (e.g., trialkylaluminum), if present, existing in the process and on the degree to which deactivation is desired.
  • active catalyst e.g., transition metal in the case of a transition metal catalyzed polymerization
  • cocatalyst e.g., trialkylaluminum
  • a fraction of the stoichiometric amount of idling agent is added based on a ratio of the moles of idling agent to the moles of transition metal present in the process.
  • Different catalysts require different ratios, but in every case the molar ratio of idling agent to the transition metal is less than the stoichiometric amount.
  • different idling agents can provide different levels of reaction suppression based on the effects of the idling agent on the active catalyst sites within the reactor. The ordinary artisan, in possession of the present disclosure, can determine the appropriate idling agent and amount of idling agent to add to a specific reaction, without undue experimentation.
  • idling agents for a typical olefin polymerization using a fluid bed reactor are Lewis bases, such as carbon dioxide, carbon monoxide, water, oxygen, and mixtures of Lewis bases, more preferably carbon monoxide, carbon dioxide, or a mixture thereof.
  • the process of idling a reaction involves the continuous polymerization of olefins in a fluidized bed reactor.
  • a fluidized bed reactor Referring to Figure 1 there is illustrated a conventional fluidized bed reaction system for polymerizing olefins.
  • the reactor 9 consists of a reaction zone 10 and a gas velocity reduction zone 2.
  • the reactor zone 10 contains the fluidized bed of enlarging polymer particles and a minor amount of catalyst being fluidized by gas flow comprising of make-up feed stream 12 and recycle gas through the reaction zone.
  • the mass gas flow rate through the bed is normally maintained above the minimum flow required for fluidization, and preferably from about 1.5 to about 10 times G ⁇ and more preferably from about 3 to 6 times G ⁇ .
  • G ⁇ is used in the accepted form as the abbreviation for the minimum gas flow required to achieve fluidization, C.Y. Wen and Y.H. Yu, "Mechanics of Fluidization” , Chemical Engineering Progress Symposium Series, Vol. 62, p. 100-101 (1966).
  • the appropriate catalyst used in the fluidized bed is preferably injected into the reactor by stream 7 with the use of an inert gas, such as nitrogen.
  • Catalyst concentration in the bed is substantially equal to the catalyst concentration in the product, for example on the order of about 0.005 to 0.5 percent of bed volume (0.0001-0.00001 % by weight) depending on the productivity of the particular catalyst in use.
  • Make up monomers, stream 12 are fed to the loop at a rate approximately equal to the rate at which polymer product is withdrawn, stream 8, from the reactor.
  • the composition of the make up gas is determined by gas analyzers on the reactor recycle gas loop. From the gas analyzers, components can be fed into the make up gas to achieve the desired gas compositions.
  • the recycle gas and make up gas are returned to the base of the reactor through the gas distribution plate 1, which also supports the resin bed when gas flow is stopped.
  • the gas which does not react with the bed in the reaction zone becomes the recycle gas and passes through the velocity reduction zone such that entrained particles can return to the bed.
  • the recycle gas is then circulated by a compressor 4 through two heat exchangers 3 and 6 in series to remove the heat of reaction absorbed from the bed before returning the gas to the bed.
  • the compressor is located between the two heat exchangers.
  • hydrogen as a component in the gas stream provides a chain transfer agent for polymerization reactions.
  • any inert gas to the catalyst and reactants can also be present in the gas stream. It is well known that the fluid bed reactor temperature is preferably maintained below the sintering temperature of the polymer particles. For the production of ethylene polymers, generally an operating temperature between 30
  • Reactor pressure can be operated at pressures of up to 1000 psig (70.0 bar), and preferably 150 to 400 psig for this particular embodiment, with operation at the higher pressures in such ranges favoring heat transfer since an increase in pressure increases the unit volume heat capacity of the gas.
  • the polymer withdrawal stream 8 removes polymer from the reactor at a rate equal to the production of polymer in the reactor, such that the bed level of the fluidized bed is maintained at a constant level.
  • Ziegler Natta catalysts typically used in the art comprise a transition metal halide, such as titanium or vanadium halide, and an organometallic compound of a metal of Group 1, 2, or 3, typically trialkylaluminum compounds (typically referred to hereinafter as "alkyl"), which serve as an activator for the transition metal halide.
  • Some Ziegler Natta catalyst systems incorporate an internal electron donor which is complexed in the alkyl aluminum or the transition metal.
  • the transition metal halide may be supported on a magnesium halide or complexed thereto.
  • This active Ziegler Natta catalyst may also be impregnated onto an inorgamc support such a silica or alumina.
  • This active Ziegler Natta catalyst may also be pre-reacted to a certain degree under appropriate conditions to form a modified catalyst referred to as prepolymer, prior to the introduction to the main fluidized bed reactor.
  • catalyst injection In order to idle polymerization of a poly olefin process, it is preferred to stop catalyst injection and, if being used, co-catalyst (e.g., trialkylaluminum) injection into the reactor (as used hereinafter, the term "catalyst” is mean to include co-catalyst, when present). Stopping these feeds to the reaction process will not stop polymerization immediately if all other process parameters such as, temperature, pressure, reactor gas composition, reactor gas velocity, etc. are held constant, since active catalyst, which is still present in the reactor, continues to react with the available monomer. This deactivation step could last for a considerable amount of time.
  • co-catalyst e.g., trialkylaluminum
  • a catalyst idling agent is injected into the reaction process gas.
  • the first type is referred to as an irreversible idling or deactivating agent.
  • the irreversible idling agent irreversibly eliminates the ability of the catalyst to react with olefins. The polymerization process will not proceed without addition of fresh catalyst. Water and oxygen are typical idling agents of the irreversible form.
  • the second type which is preferred for this invention as an idling agent, is referred to as a reversible idling or deactivating agent.
  • Carbon monoxide and carbon dioxide are typical idling agents of the reversible form. These idling agents usually inhibit active catalyst sites which prevent polymerization for a limited time under normal reaction conditions. Although addition of fresh catalyst is preferred to re-establish operating conditions, some product may be produced as the reversible idling agents come off the catalyst active sites.
  • a predetermined amount of a specific idling agent is injected into the process, preferably into the gas loop upstream of the fluidized bed which prevents active catalyst sites from reacting further with the olefin which, in turn, limits polymerization to the desired rate.
  • the amount of idling agent necessary can be determined by the ordinary artisan without undue experimentation, since the amount of catalyst is known by, for instance, the knowledge of the amount of catalyst in the product along with the bed volume. Thus, the amount of idling agent to add is "predetermined".
  • the invention works by reducing reaction rates, the invention is particularly applicable to all types of poly olefin fluidized bed reactors, although one of skill in the art will recognized that the invention is more broadly applicable to any polymerization reaction using a catalyst system that can be deactivated, such as a polyester reaction, reactions in solution, etc.
  • the level of successful idling of the reactor obtained will depend on the type of catalyst system in use, including any inorganic support structure such as MgCl 2 or silica, but the general utility of the invention results from the interaction of the catalyst with the idling agent.
  • the present invention is applicable to polyethylene fluidized bed reactors, and even more preferably applicable for polyethylene fluidized bed reactors using a Ziegler Natta catalyst with a MgCl 2 support.
  • the idling agent is added to the reactor gas loop.
  • the idling agent used in the process according to the present invention can be any catalyst deactivating agent with the catalyst system in use, but in the more preferred embodiment of a polyethylene fluidized bed reactors using a Ziegler Natta catalyst with a MgCl 2 support, it is preferred that carbon monoxide, carbon dioxide, or a mixture thereof, be used as the idling agent.
  • reaction suppression of different idling agents on different catalyst systems must be determined for each particular case.
  • the preferred ratio of carbon monoxide idling agent, to the titanium in the catalyst that provides adequate reaction suppression is in the range of 0.00366 to 0.0684 mole/mole of Ti, preferably 0.02 to 0.045 mole/mole Ti, most preferably about 0.038 mole/mole Ti.
  • the amount of idling agent necessary will be less than 1 percent, on a mole/mole basis, of the amount of catalyst in the system.
  • the idling agent can be injected anywhere along the gas loop recycle line. More, preferably, a quicker response results when the injection is located after the second gas recycle heat exchanger 6 and directly below the distribution plate is most preferred.
  • ethylene polymers ethylene copolymers, or polyethylene also includes copolymers composed of ethylene and one or more other olefins (comonomer). These other olefins are preferably alpha-olefins.
  • polymers are terpolymers of ethylene and two or more comonomers.
  • suitable alpha-olefins include, but are not limited to, propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-l, and octene-1, with hexene-1, 4-methylpentene-l, and butene-1 being most preferred.
  • Key elements in the reactor loop for a preferred embodiment of the reactor are illustrated in Figure 1 and include reactor vessel 9, heat exchangers 3 and 6, compressor 4, and gas distributor plate 1.
  • a conventional gas phase fluidized bed polyethylene reaction process such as disclosed in U.S. Patent No. 5,332,706 (incorporated herein by reference) is utilized and which is modified as shown in Figure 1.
  • a conduit for introducing 100% carbon monoxide gas at a pressure of approximately 900 psig (63.1 bar) from a cylinder opens into the recycle conduit at a distance 10 feet (3.05 m) from the reentry in the lower part of the reactor.
  • the distribution plate in the reactor contains a fluidized bed consisting of linear low density polyethylene powder.
  • the reaction gas mixture 67% by volume of nitrogen, 25% of ethylene, 4% of hydrogen, and 4% of 1- hexene, flows through the fluidized bed at a pressure of 300 psig (21.7 bar), at 183 °F (84 °C) and with an upward fluidization velocity of 1.7 ft/s (0.518 m/s).
  • idling operation begins by immediately stopping catalyst injections into the reactor. Simultaneously, the measured amount of carbon monoxide gas contained in the conduit was introduced in the reactor in less than 30 seconds, in a quantity of 0.038 mole per mole titanium, by dropping the pressure in the conduit from 900 psig (63.1 bar) to 300 psig (21.7 bar). It was discovered that the reaction idled within 15 minutes with a reactor bed temperature differential, approximately 3.6 °F (2 °C), and without any detrimental effects, i.e. producing large agglomerates. The reactor pressure was maintained at 300 psig (21.7 bar) and the gas compositions were also maintained at conditions prior to injection.
  • the reactor operation is carried out under conditions which are identical with those given in Example 1.
  • Example 2 A different incident occurs where the powder withdrawal system experiences pluggages that prevent the removal of polymer powder from the reactor.
  • the idling operation is carried out the same way as in Example 1 to prevent the fluidized bed to reach the high levels where the bed begins to carryover into the gas recycle stream.
  • the reaction idled within 15 minutes with a reactor bed temperature differential, approximately 3.6 °F (2 °C), and without any detrimental effects, i.e. producing large agglomerates.
  • the reactor pressure and gas compositions were maintained at conditions prior to injection and the fluidized bed level remained constant. The reaction was restarted in the same manner as in Example 1.
  • an idling agent can be added to deactivate a catalyst involved in a polymerization process in a predetermined amount so that the polymerization process can be immediately restarted solely by introduction of fresh catalyst.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Polymerisation Methods In General (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

La présente invention concerne un procédé pour ralentir une réaction de polymérisation. Selon ce procédé, on injecte une quantité suffisante d'agent désactivant de manière à désactiver le catalyseur tout en permettant le rétablissement de la réaction simplement en ajoutant un catalyseur frais. Le procédé de ralentissement permet de maintenir des conditions de réaction de polymérisation pendant un arrêt et de réduire de manière significative le temps associé au rétablissement des conditions de réaction de polymérisation.
EP98901780A 1997-01-13 1998-01-13 Ralentissement temporaire d'une reaction de polymerisation Withdrawn EP0952990A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US3448897P 1997-01-13 1997-01-13
US34488P 1997-01-13
US638298A 1998-01-12 1998-01-12
US6382 1998-01-12
PCT/US1998/000553 WO1998030599A1 (fr) 1997-01-13 1998-01-13 Ralentissement temporaire d'une reaction de polymerisation

Publications (1)

Publication Number Publication Date
EP0952990A1 true EP0952990A1 (fr) 1999-11-03

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP98901780A Withdrawn EP0952990A1 (fr) 1997-01-13 1998-01-13 Ralentissement temporaire d'une reaction de polymerisation

Country Status (5)

Country Link
EP (1) EP0952990A1 (fr)
JP (1) JP2002514248A (fr)
CN (1) CN1239481A (fr)
BR (1) BR9806869A (fr)
WO (1) WO1998030599A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0959082A1 (fr) 1998-05-19 1999-11-24 Bp Chemicals S.N.C. Procédé de polymérisation
EP0959081A1 (fr) * 1998-05-19 1999-11-24 Bp Chemicals S.N.C. Procédé de polymérisation en phase gazeuse
US6897269B2 (en) 2002-12-27 2005-05-24 Univation Technologies, Llc Processes for transitioning between Ziegler-Natta and alumoxane-based single-site polymerization catalysts
US6858684B2 (en) 2002-12-30 2005-02-22 Univation Technologies, Llc Processes for transitioning between various polymerization catalysts
US6949612B2 (en) 2002-12-31 2005-09-27 Univation Technologies, Llc Processes for transitioning between metallocene and Ziegler-Natta polymerization catalysts
US6841630B2 (en) 2002-12-31 2005-01-11 Univation Technologies, Llc Processes for transitioning between chrome-based and mixed polymerization catalysts
US6833417B2 (en) 2002-12-31 2004-12-21 Univation Technologies, Llc Processes for transitioning between chrome-based and mixed polymerization catalysts
DE102005035477A1 (de) * 2005-07-26 2007-02-01 Basell Polyolefine Gmbh Verfahren zur Steuerung der relativen Aktivität der unterschiedlichen aktiven Zentren von Hybridkatalysatoren
EP2536767B1 (fr) * 2010-02-18 2015-05-06 Univation Technologies, LLC Procédés d'exploitation d'un réacteur de polymérisation

Family Cites Families (3)

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Publication number Priority date Publication date Assignee Title
US5200502A (en) * 1992-08-26 1993-04-06 Union Carbide Chemicals & Plastics Technology Corporation Deactivator reagent for olefin polymerization catalysts
US5414063A (en) * 1993-03-30 1995-05-09 Huntsman Polypropylene Corporation Process for the production of polypropylene
CA2126796A1 (fr) * 1993-06-28 1994-12-29 Robert Converse Brade, Iii Utilisation de bases de lewis pour ralentir un procede de polymerisation d'olefines, catalyse par un metallocene

Non-Patent Citations (1)

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Title
See references of WO9830599A1 *

Also Published As

Publication number Publication date
CN1239481A (zh) 1999-12-22
BR9806869A (pt) 2000-04-18
WO1998030599A1 (fr) 1998-07-16
JP2002514248A (ja) 2002-05-14

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