CN120813613A

CN120813613A - Method for modifying supported catalysts during olefin polymerization

Info

Publication number: CN120813613A
Application number: CN202480016503.XA
Authority: CN
Inventors: M·D·卢卡斯; R·W·艾默尔曼; C·T·伦德; R·E·派克尤诺; A·S·希尔瓦; K·A·史蒂文斯; X·叶; J·R·费舍尔; S·恰尔沃; G·L·布劳萨德; B·A·加里森; L·G·蒙赛奥克斯
Original assignee: ExxonMobil Technology and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 2023-03-13
Filing date: 2024-03-06
Publication date: 2025-10-17
Also published as: EP4680654A1; WO2024191701A1

Abstract

Polymer sheeting may be reduced by increasing the contact time between the catalyst solution and the catalyst slurry. The polymerization process may include introducing a catalyst slurry into a first line in fluid communication with a mechanically agitated mixing tank, introducing at least a first portion of a catalyst solution into a second line in fluid communication with a mechanically agitated mixing tank, contacting the catalyst slurry with the catalyst solution in the mechanically agitated mixing tank to obtain a modified catalyst slurry from the mechanically agitated mixing tank, the modified catalyst slurry comprising a modified supported catalyst that incorporates at least a portion of the first catalyst compound or the second catalyst from the catalyst solution, feeding the modified catalyst slurry to a fluidized bed gas phase reactor, and polymerizing alpha-olefins in the fluidized bed gas phase reactor under polymerization conditions to obtain polyolefin.

Description

Method for modifying supported catalysts during olefin polymerization

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application 63/489,951 entitled "method for modifying supported catalysts during olefin polymerization" filed on day 13, 2023, which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates to a process for polymerizing one or more olefins, and more particularly, to a process for polymerizing one or more olefins using an enhanced supported catalyst mixing technique prior to polymerization.

Background

Gas phase polymerization may be used to polymerize ethylene or ethylene and one or more olefin comonomers. The gas-phase polymerization process carried out in a fluidized bed is particularly economical. One or more olefin monomers and catalyst particles comprising an activated catalyst compound may be introduced into the polymerization reactor, wherein the olefin monomer(s) may be polymerized in the presence of the catalyst particles to produce a polyolefin product, preferably in the form of fine particles.

During polymerization, the catalyst particles (i.e., supported catalyst) may begin to overheat, especially when the catalyst compounds on the catalyst particles have an aggressive dynamic profile (AN AGGRESSIVE KINETIC profile). When the catalyst particles overheat, the polymer particles within the reactor may start to stick together, which may lead to a final accumulation of polymer within the reactor. In some cases, the accumulation of polymer within the reactor, commonly referred to as agglomeration, clumping, or sheeting (sheeting), can lead to process upsets, even reactor shutdowns. The term sheeting is used herein.

One way in which the overheating of the catalyst particles may be moderated is by varying the proportion of catalyst compound(s) on the catalyst particles. For maximum process flexibility, modification of the catalyst particles may occur in situ prior to delivery to the polymerization reaction without process shutdown. In some examples, the catalyst solution may be contacted with the catalyst particles to introduce additional catalyst compounds onto the catalyst particles and/or to introduce different catalyst compounds onto the catalyst particles. The introduction of additional catalyst compound and/or different catalyst compound into the catalyst solution of the catalyst particles may be referred to as "trim catalyst (A TRIM CATALYST)" or "trim catalyst solution" because the catalyst solution adjusts the properties of the original catalyst particles. Unfortunately, modifying catalyst particles in situ in the foregoing manner may lead to continued challenges of suboptimal catalyst activation and process control, including sheeting of the resulting polymer. Short and/or variable contact times between the catalyst particles and the trim catalyst solution can be particularly problematic because multiple supported catalysts with different polymerization properties can be produced.

Some references that may be of interest in the art include U.S. patent No. 10,927,205, U.S. patent publication nos. US2022/0033536 and US2022/0033537, and international patent publication No. WO2022/174202.

Thus, there remains a need for improved methods for polymerizing one or more olefin monomers during gas phase polymerization to reduce or eliminate polymer build-up within the reactor.

Disclosure of Invention

Summary of The Invention

In various aspects, the methods of the present disclosure include providing a catalyst slurry comprising a supported catalyst comprising a support material, at least one catalyst compound, and at least one activator, introducing the catalyst slurry into a first line in fluid communication with a mechanically agitated mixing tank, introducing at least a first portion of a catalyst solution comprising a first catalyst compound that has been contained on the supported catalyst or a second catalyst compound that is different from the first catalyst compound and that is not contained on the supported catalyst into a second line in fluid communication with the mechanically agitated mixing tank, contacting the catalyst slurry with the catalyst solution in the mechanically agitated mixing tank to obtain a modified catalyst slurry from the mechanically agitated mixing tank, the modified catalyst slurry comprising a modified supported catalyst that incorporates at least a portion of the first catalyst compound or the second catalyst from the catalyst solution, feeding the modified supported catalyst to a fluidized bed polymerization reactor under gas phase polymerization conditions, and obtaining an alpha-olefin.

These and other features and attributes of the disclosed methods of the present disclosure, as well as advantageous applications and/or uses thereof, will be apparent from the detailed description that follows.

Drawings

To assist one of ordinary skill in the pertinent art in making and using the subject matter herein, reference is made to the appended drawings. The following drawings are included to illustrate certain aspects of the disclosure and should not be taken as an exclusive configuration. The disclosed subject matter is capable of numerous modifications, alterations, combinations, and equivalents in form and function, as will occur to persons skilled in the art upon reading the present disclosure.

FIG. 1 is a schematic block diagram of a gas phase reactor system in which mixing of catalyst slurry and catalyst solution may be performed in a mechanically agitated mixing tank.

FIG. 2 is a schematic block diagram of a gas phase reactor system in which mixing of catalyst slurry and catalyst solution may be performed in-line upstream of a static mixer or mixing block (mixing block).

FIG. 3 is a schematic block diagram of a gas phase reactor system in which mixing of catalyst slurry and catalyst solution may be performed in-line upstream of a mechanically agitated mixing tank.

FIG. 4 is a graphical representation of H ₂/ethylene flow ratio and degree of polymer sheeting under conventional catalyst slurry/catalyst solution contact conditions and extended catalyst slurry/catalyst solution contact conditions in accordance with the disclosure herein.

Detailed Description

As described above, the catalyst particles (i.e., supported catalyst) may be modified in situ prior to conducting the polymerization reaction to mitigate polymer sheeting. However, in situ modification of the catalyst particles may lead to ineffective catalyst activation and persistent difficulties in the polymerization process. The foregoing difficulties may be addressed by the disclosure herein. In particular, the present disclosure provides for increased and/or less variable contact time between catalyst particles and catalyst solution when producing modified supported catalysts. As a result, more consistent polymerization performance can be achieved.

Definition of the definition

Various specific embodiments, versions and examples of the invention will now be described, including preferred embodiments and definitions employed for understanding the invention as claimed. While the following detailed description presents certain preferred embodiments, those skilled in the art will appreciate that these embodiments are merely exemplary and that the invention may be practiced in other ways. For purposes of determining infringement, the scope of the invention will refer to any one or more of the appended claims, including their equivalents, and elements or limitations that are equivalent to those that are recited. Any reference to the "invention" may refer to one or more, but not necessarily all, of the inventions defined by the claims.

The indefinite article "a" or "an" as used herein shall mean "at least one" unless specified to the contrary or the context clearly indicates otherwise. Thus, embodiments using "alpha-olefins" include embodiments in which one, two, or more alpha-olefins are used, unless otherwise indicated or the context clearly indicates that only one alpha-olefin is used.

Unless otherwise indicated, all numbers expressing quantities in this disclosure are to be understood as being modified in all instances by the term "about". It should also be understood that the precise numerical values used in the specification and claims constitute specific embodiments.

The term "and/or" as used in phrases such as "a and/or B" is intended herein to include "a and B", "a or B", "a" and "B".

As used herein, "wt%" refers to weight percent, "volume%" refers to volume percent, "mole%" refers to mole percent, "ppm" refers to parts per million, "ppm wt" and "wppm" are used interchangeably and refer to parts per million by weight. All concentrations are expressed based on the total amount of the composition in question, unless otherwise indicated.

For purposes of this disclosure, unless otherwise indicated, the nomenclature of the elements follows the new representation version of the periodic table of elements as provided in Hawley's Condensed Chemical Dictionary, 16 th edition, john Wiley & Sons, inc., (2016), appendix V.

The term "optional" or "optionally" as used herein means that the subsequently described event or circumstance occurs or does not occur (or that the elements are present or absent), and that the description includes instances where said event or circumstance occurs and instances where it does not.

A "reactor" is any type of vessel or containment device in any configuration of one or more reactors and/or one or more reaction zones, wherein similar polymers are produced. The term "gas phase polymerization" refers to the production of a polymer in a gas phase reactor (herein simply referred to as a "reactor"). It should also be noted that when referring to a "gas phase" polymerization or reactor, it is contemplated that the monomers will typically react in the gas phase in the reaction zone, however, the monomers need not necessarily be supplied to the reactor in the gas phase. Instead, the monomers may be supplied in the gas phase, liquid phase (condensed phase) or mixed gas-liquid phase. Thus, when a gaseous monomer stream or recycle gas stream is referred to herein as part of a gas phase polymerization reactor system or process, it is understood that such gas stream may actually be at least partially condensed (i.e., in a gas-liquid mixed phase). In other words, in the context of a gas phase reaction system as described herein, any stream referred to as a gas stream, recycle gas, etc. may be considered to be optionally at least partially liquefied, as known in the art. See the discussion of the so-called "condensing mode" of operation of certain gas phase polymerization reactors, for example in Namkajorn et al, condensed Mode Cooling for Ethylene Polymerization:part III. Induced condensing agents have an effect on particle morphology and polymer properties (The Impact of Induced Condensing Agents on Particle Morphology and Polymer Properties),J.Macromol.Chem.and Phys.217,1521-1528(Wiley2016), where it is noted that in some fluidized bed gas phase polymerization reactors, the recycle stream or recycle gas may be cooled to a temperature below its dew point such that it is partially liquefied and then fed to the bottom of the fluidized bed reactor where the latent heat of vaporization of the liquid in the feed absorbs the heat of polymerization, thereby providing increased cooling and the potential for increased reaction rates.

"Alkoxy" includes an oxygen atom bonded to an alkyl group, which is a C ₁ to C ₁₀ hydrocarbon group. The alkyl group may be a linear, branched or cyclic alkyl group. The alkyl groups may be saturated or unsaturated. In at least one embodiment, the alkyl group may comprise at least one aromatic group.

The terms "antistatic agent", "continuity additive", "continuity aid" and "anti-fouling agent" are interchangeable and refer to a compound or mixture of compounds, such as solids and/or liquids that may be used to reduce reactor fouling during polymerization. Reactor fouling may be caused by polymer accumulation within the reactor. Reactor fouling can manifest itself in many phenomena including sheeting of the reactor walls, blockage of inlet and outlet lines, formation of large agglomerates, or other forms of polymer accumulation within the reactor that can lead to reactor shutdown. The antistatic agent may be used as part of the catalyst composition or introduced directly into the reactor independently of the catalyst composition. In some embodiments, the antistatic agent may be contained on a carrier that also supports one or more catalysts.

The term "catalyst" may be used interchangeably with the terms "catalyst compound", "catalyst precursor", "transition metal compound", "transition metal complex" and "procatalyst".

A "catalyst system" is a combination of one or more catalyst compounds, an activator, an optional co-activator, and an optional support material. For purposes of this disclosure, when the catalyst system is described as comprising a neutral stable form of a component, those skilled in the art will understand that the ionic form of the component is the form that reacts with the monomer to produce the polymer. The catalyst systems, catalysts, and activators of the present disclosure are intended to encompass ionic forms in addition to the neutral forms of the compounds/components.

The terms "group," "group," and "substituent" are used interchangeably herein.

The term "hydrocarbon" refers to a class of compounds having hydrogen bonded to carbon and encompasses saturated hydrocarbon compounds, unsaturated hydrocarbon compounds, and mixtures of hydrocarbon compounds (saturated and/or unsaturated), including mixtures of hydrocarbon compounds having different numbers of carbon atoms. The term "C _n" refers to hydrocarbon(s) or hydrocarbyl groups having n carbon atom(s) per molecule or group, where n is a positive integer. Such hydrocarbon compounds may be one or more of linear, branched, cyclic, acyclic, saturated, unsaturated, aliphatic, or aromatic.

The terms "hydrocarbyl (hydrocarbyl radical)", "hydrocarbyl (hydrocarbyl group)" or "hydrocarbyl (hydrocarbyl)" are used interchangeably and are defined to mean a group consisting of only hydrogen and carbon atoms, and which when removed from the parent compound carries at least one unfilled valence position.

The term "optionally substituted" means that the hydrocarbon or hydrocarbyl group may be unsubstituted or substituted. Any hydrocarbyl group herein may be optionally substituted unless otherwise indicated as being specifically unsubstituted. The term "substituted" means that at least one hydrogen atom in the parent hydrocarbyl has been replaced with at least one non-hydrogen group, such as a hydrocarbyl, heteroatom, or heteroatom-containing group.

An "olefin" is a linear, branched or cyclic compound of carbon and hydrogen having at least one double bond. When a polymer or copolymer is referred to as comprising an olefin, such as ethylene and/or at least one C ₃ to C ₂₀ alpha-olefin, the olefin present in such polymer or copolymer is the polymerized form of the olefin. For example, when a copolymer is said to have an "ethylene" content of about 35 wt% to about 55 wt%, it is understood that the repeat units/monomer units (mer units) or simply units in the copolymer are derived from ethylene in the polymerization reaction, and the derived units are present at about 35 wt% to about 55 wt%, based on the weight of the copolymer. For the purposes of this disclosure, ethylene should be considered an alpha-olefin.

"Polymer" has two or more identical or different repeating units/monomer units or simply units (monomer units). "homopolymer" is a polymer having identical units. "copolymer" is a polymer having two or more units that are different from each other. "terpolymer" is a polymer having three units that differ from one another. The term "different" as used in reference to units indicates that the units differ from each other in at least one atom and/or are isomerically different. The definition of copolymer as used herein includes terpolymers and the like. Likewise, the definition of polymer as used herein includes homopolymers, copolymers and the like. Furthermore, the terms "polyethylene copolymer", "ethylene copolymer" and "ethylene-based polymer" are used interchangeably to refer to a copolymer comprising at least 50 mole% of units derived from ethylene.

The term "characteristic mass transfer time (CHARACTERISTIC MASS TRANSFER TIME)" refers to the time scale in which diffusion occurs. Once a plurality (e.g., 2, 3, 4, 5, or even more) of characteristic mass transfer times have elapsed, diffusion-based mixing can be considered complete. The process of the present disclosure can extend the contact time between the catalyst solution and the catalyst slurry beyond the characteristic mass transfer time at which interparticle diffusion occurs. By extending the contact time beyond the characteristic mass transfer time, additional time is available for the second catalyst to diffuse into the supported catalyst (intra-particle diffusion) and for catalyst activation to occur. The time for mass transfer to occur can be reduced beyond that achieved with diffusion alone, for example, via the use of a mechanically agitated mixing tank.

Polymerization process and activation of catalyst compounds

When using a supported catalyst containing one or more catalyst compounds, it may be desirable to modify the final supported catalyst by introducing additional catalyst compound(s) onto the supported catalyst in order to alter the dynamic distribution during polymerization or alter the composition or characteristics of the polymer being produced. The additional catalyst compound(s) being introduced may increase the loading of catalyst compound already present on the supported catalyst and/or introduce a different catalyst compound not already present on the supported catalyst. One way in which the supported catalyst modification may be performed is by contacting the supported catalyst in (i) a catalyst slurry with (ii) a catalyst solution containing one or more catalyst compounds, thereby producing a modified supported catalyst in a modified catalyst slurry. The modified catalyst slurry may have a different loading of at least one catalyst compound on the support material than the original (pre-contact) catalyst slurry. When producing the modified catalyst slurry in situ in the manner described above, the dynamic distribution and/or contact time of the modified catalyst slurry is desirably controlled with a specified accuracy. Otherwise, insufficient dynamic control may, for example, lead to thermal swings and pressure differentials, resulting in rheological changes in the catalyst slurry and/or catalyst solution, which may lead to disturbances within the catalyst system and potentially to polymer sheeting. Insufficient activation may also occur for the newly introduced catalyst compound(s) and thus the catalyst performance cannot be changed to a sufficient extent during the polymerization reaction. For example, if the dynamic profile does not change to a sufficient extent, the overly aggressive dynamic profile may result in polymer sheeting within the reactor. Alternatively or additionally, if the supported catalyst is not modified to a sufficient extent, off-spec polymer may be produced during the gas phase polymerization reaction. Inconsistent modification and activation can prove to be very problematic when introducing modified supported catalysts produced from multiple sources and/or formed in situ in different pipelines, as erroneous polymer products or sheeting can become more prevalent. These and other problems may be caused by inconsistencies between the catalyst particles and the trim catalyst solution and/or short contact times.

Without wishing to be bound by theory or mechanism, it is believed that the catalyst compound introduced into the supported catalyst from the catalyst solution may undergo suboptimal activation due to limited diffusion into the interior of the support material to enable the catalyst compound to contact the co-supported activator within the support material. The activation of the catalyst compounds introduced from the catalyst solution may be enhanced by increasing the contact time between the catalyst slurry and the catalyst solution before the modified catalyst slurry produced from the catalyst slurry containing the supported catalyst and the catalyst solution enters the polymerization reactor. The highly variable contact time can also be problematic because the original catalyst particles may undergo more or less modification than desired, potentially resulting in the formation of undesirable polymer products (e.g., by continuously feeding supported catalysts having an unintentionally different amount of activated catalyst compound thereon, which varies over time due to such inconsistent contact time). Surprisingly, enhanced catalyst activation caused by increased contact time between the catalyst solution and the catalyst slurry according to the disclosure herein can provide improved performance during gas phase polymerization reactions after modification thereof with supported catalysts. At a minimum, enhanced catalyst activation may reduce sheeting within a gas phase polymerization reactor. Various approaches for increasing the contact time between catalyst slurry and catalyst solution to provide improved polymerization performance are described in further detail herein. According to a more specific example, the increased contact time between catalyst slurries can exceed at least the characteristic mass transfer mixing time.

While the present disclosure provides enhanced slurry catalyst activation via more efficient contact of the supported catalyst with the catalyst solution, it goes without saying that consistent delivery of the modified supported catalyst to the reactor is also a factor in achieving good polymerization performance. For example, when introducing a modified supported catalyst through multiple lines, maintaining the delivery rate (DELIVERY RATE) consistency between lines can maintain improved polymerization performance. Providing a consistent delivery rate of the modified supported catalyst through multiple lines may include heating or cooling the lines individually to control the viscosity and delivery rate, or using pinch valves to slow the delivery rate in each line as desired.

For a better understanding of embodiments of the present disclosure, reference is now made to the drawing showing a polymerization process and reactor system in which a modified catalyst slurry may be produced and fed into a gas phase polymerization reactor. Those of ordinary skill in the art will appreciate that elements such as pumps, heat exchangers, valves, and similar system components may be present in the depicted process and reactor systems, but have been omitted for clarity. Furthermore, elements having similar structure and function in the various figures will be referred to herein using common reference numerals and for brevity will only be described in detail when they first appear.

Fig. 1 is a block schematic diagram of a gas phase reactor system 100 in which mixing of catalyst slurry and catalyst solution may be performed using a mechanically agitated mixing tank. As shown, a first catalyst-containing mixture containing supported catalyst in a suitable carrier liquid may be introduced into the first vessel 102. The first vessel 102 optionally may be a stirred holding vessel configured to maintain a substantially constant solid concentration of supported catalyst in the catalyst slurry. As another option, the vessel 102 may be maintained at an elevated temperature, for example, 30 ℃,40 ℃, or 43 ℃ to 45 ℃, 60 ℃, or 75 ℃. The elevated temperature may be obtained by electrically heating the holding vessel with, for example, a heating blanket. Maintaining the vessel at an elevated temperature may further reduce or eliminate the formation of solid residues on the vessel walls that might otherwise slip off the walls and cause plugging of downstream transfer lines. In at least one embodiment, the holding vessel may have a volume of 0.75m ³、1.15m³、1.5m³、1.9m³ or 2.3m ³ to 3m ³、3.8m³、5.7m³ or 7.6m ³. It should be appreciated that the volume of the holding vessel may be selected in response to the rate of catalyst consumption. In a non-limiting example, the volume of the holding vessel can be selected to provide a run time (a run time) of at least about 12 hours, such as about 12 hours to about 96 hours, or about 12 hours to about 72 hours, or about 12 hours to about 48 hours, or about 12 hours to about 24 hours, or about 24 hours to about 72 hours, or about 48 hours to about 96 hours.

The supported catalyst may comprise a support material, at least one activator, and at least one catalyst compound. At least one catalyst compound may comprise at least the first catalyst compound and optionally a second catalyst compound, wherein the first catalyst compound and the second catalyst compound are different from each other. The first catalyst-containing mixture may comprise a catalyst slurry.

A second catalyst-containing mixture comprising a first catalyst compound or a second catalyst compound may be introduced into the second vessel 106. The second catalyst-containing mixture may comprise a catalyst solution. The second vessel 106 optionally may be a tank of sufficient volume to appropriately modify the supported catalyst according to the description herein. Kettles for the catalyst solutions may have a volume of 0.38m ³、0.75m³、1.15m³、1.5m³、1.9m³ or 2.3m ³ to 3m ³、3.8m³、5.7m³ or 7.6m ³. It should be appreciated that the volume of the tank may be selected in response to the rate of catalyst consumption. In a non-limiting example, the volume of the tank can be selected to provide a run time of at least about 12 hours, such as about 12 hours to about 96 hours, or about 12 hours to about 72 hours, or about 12 hours to about 48 hours, or about 12 hours to about 24 hours, or about 24 hours to about 72 hours, or about 48 hours to about 96 hours. The kettle for the catalyst solution may be maintained at an elevated temperature, for example 30 ℃,40 ℃, or 43 ℃ to 45 ℃,60 ℃, or 75 ℃, which may be obtained by electrically heating the kettle with, for example, a heating blanket. Maintaining the kettle at an elevated temperature may provide reduced or eliminated foaming when combining the catalyst slurry with the catalyst solution in accordance with the description herein.

In a conventional reactor system for producing a modified supported catalyst, catalyst slurry is conveyed via line 104 and catalyst solution is conveyed via line 108 to a static mixer or mixing block that provides a total contact time between the catalyst solution and the catalyst slurry of about 1-2 minutes as the resulting modified catalyst is conveyed via line 112 to reactor 114. The contact time in the static mixer or the mixing block itself may be in the range of only a few seconds.

In one process configuration of the present disclosure shown in fig. 1, the contact time between the catalyst solution and the catalyst slurry can be increased by supplementing or replacing the static mixer or mixing block of an existing system with a mechanically agitated mixing tank, such as mixing tank 110. A mechanically agitated mixing tank may provide more thorough (higher quality) and longer mixing than is possible with a static mixer or mixing block, as discussed later. The catalyst slurry is transported from the first vessel 102 via line 104 and the catalyst solution is transported from the second vessel 106 via line 108 directly to a mechanically agitated mixing tank 110, which mechanically agitated mixing tank 110 may include one or more impellers 111 to facilitate agitation therein. For example, one or more impellers 111 may be present in a mixing tank 110 defining a tilted blade turbine. In addition to the volume and configuration of the mechanically agitated mixing tank 110, the rotational rate of the one or more impellers 111 may affect the residence time of the catalyst slurry in the mixing tank 110. The mechanically agitated mixing tank 110 may be characterized by a volume and configuration sufficient to provide a contact time at least about 5 minutes greater than that produced by the mixing block or static mixer alone. In a non-limiting example, the mechanically agitated mixing tank 110 can provide a contact time (ranging from any of the aforementioned lower limits to any of the aforementioned upper limits, e.g., 30 to 40 minutes) between the catalyst slurry and the catalyst solution within the mixing tank 110 of about 20, 22, 25, 27, 28, or 30 minutes to about 30, 33, 35, 37, 38, 39, 40, 42, 45, or 50 minutes. In addition to the increased contact time, the mechanically agitated mixing tank 110 can improve mixing quality beyond diffusion limited processes alone. Without wishing to be bound by theory or mechanism, mechanical agitation may provide greater homogenization of the catalyst solution throughout the catalyst slurry and reduce the thickness of the mass transfer boundary layer on the catalyst particles, thereby allowing faster mass transfer of catalyst from the catalyst solution into the catalyst particles for activation to occur.

The mechanically agitated mixing tank may, for example, have a total volume of from about 10L to about 30L, or from about 10L to about 20L, or from about 15L to about 25L, or from about 20L to about 30L. Volumes within the foregoing ranges, in combination with the design configuration of the mechanically agitated mixing tank, may be sufficient to provide a contact time in the mechanically agitated mixing tank of from about 30 minutes to about 40 minutes. It goes without saying that depending on the catalyst feed rate, the volume can be adjusted up or down from the above ranges to keep the contact time within the desired specified range. Variations in catalyst productivity (catalyst productivity) (kg catalyst/kg polymer) and/or variations in production rate (kg/hr of polymer production) may further facilitate increases or decreases in the volume of the mechanically agitated mixing tank to achieve the desired contact time and/or mixing quality.

In addition to volume, other mechanically agitated mixing vessels suitable for use in the present disclosure include, but are not limited to, any of the types of agitated mixing vessels described in Handbook of Industrial Mixing (2004, editors: paul, atiemo-Obeng, and Kresta). The container defining the mechanically agitated mixing tank may comprise any suitable shape, such as a generally cylindrical shape, having various types of container heads and bottoms (e.g., flat, oval, or conical). Depending on the impeller selection, baffles may optionally be used to prevent solids from rotating and enhance axial mixing. In some embodiments, the containers may be staged with horizontal baffles to provide multiple connected chambers. In any embodiment, the container may be vertical, horizontal, or sloped. In any embodiment, the impeller(s) may be mounted from the top, bottom or sides of the vessel, axially or obliquely, centrally or eccentrically, or any combination thereof. Each impeller (e.g., one, two, three, four, or even more impellers of the same or different types) may be any of axial flow, radial flow, mixed flow, intimate contact, helical band (spiral), or any combination thereof. The impeller(s) may be sized for different vessel diameter ratios, located at different heights from the bottom of the vessel, and may be of different types to affect different mixing conditions in different portions of the vessel. The inlet and effluent locations may be located at different locations of the vessel, depending on the desired mixing performance. The liquid level within the container may be manipulated to be partially filled to completely filled with liquid (i.e., no vapor space or limited vapor space).

In one non-limiting example, the vessel may be a cylindrical vessel having a conical bottom with a 15 degree taper and shielded with an axial impeller shaft equipped with two inclined turbine blade impellers. The catalyst slurry and catalyst solution may be charged to the top of a vessel filled with liquid and the effluent may be withdrawn from the bottom, with a straight line from the inlet to the outlet passing through the space of the impeller.

As the catalyst slurry and catalyst solution are contacted in the mixing tank 110, a modified catalyst slurry comprising a modified supported catalyst is obtained and then transported via line 112 to reactor 114. Optionally, one or more static mixers 115 can reside in line 112, which can provide additional mixing contact time if desired. Although line 112 has been depicted in fig. 1 as a single line, it is understood that line 112 may alternatively comprise multiple lines to deliver modified catalyst slurry to reactor 114 at multiple locations and/or at different flows (e.g., the lines may be in a configuration such that modified catalyst slurry flows in parallel through the lines). For example, the lines 112 may include one, two, three, four, five, six, or more lines in parallel, each operating independently of the other and having independent thermal control relative to the other. Further, other components may be delivered to the reactor 114 via line 112 (or lines 112), combined with the modified catalyst slurry in one or more lines, and/or introduced in one or more separate lines without modified catalyst slurry. These other components are discussed in more detail below.

It should be understood that while a modified catalyst slurry comprising at least two catalyst compounds is described herein, if appropriate for a particular process (e.g., wherein the supported catalyst comprises catalyst compounds deposited thereon and the catalyst solution comprises the same catalyst compounds such that controlling the amount of catalyst solution mixed with the catalyst slurry actually controls the amount of catalyst compounds deposited), the modified catalyst slurry may comprise a single catalyst compound. Also, the modified catalyst slurry may comprise three or more catalyst compounds, depending on the particular process requirements (e.g., one, two, or three compounds may be present on the supported catalyst in the slurry, and one or two catalyst compounds are added by solution to provide immediate control of the compound ratios, and so on for different amounts of different catalyst compounds).

The reactor 114 may include a reaction zone and a velocity reduction zone. The reaction zone may comprise a bed comprising growing polymer particles, formed polymer particles and small amounts of catalyst particles fluidized by the continuous flow of gaseous monomer and diluent to remove the heat of polymerization passing through the reaction zone. An olefinic feed gas can be provided to and recycled through the reactor 114. Optionally, some of the recycle gas may be cooled and compressed to form a liquid (e.g., where the gas includes an Induced Condensing Agent (ICA), which may increase the heat removal capacity of the recycle gas stream upon reentry into the reaction zone, the make-up of the recycle gas stream by the gaseous monomer may be at a rate equal to the rate at which the particulate polymer product and monomer associated therewith are discharged from the reactor and the composition of the gas passing through the reactor may be adjusted to maintain a substantially steady gaseous composition within the reaction zone, the gas exiting the reaction zone may flow to a velocity reduction zone, wherein entrained particles can be removed, for example, by slowing down and falling back to the reaction zone below the deceleration zone, if desired, the reaction zone can be separated in a separation system, the recycle gas may be passed through a heat exchanger, wherein at least a portion of the heat of polymerization may be removed and/or the recycle gas may be compressed and returned to the reaction zone.

In another suitable process configuration of the present disclosure, the contact time between the catalyst solution and the catalyst slurry may be increased by contacting the catalyst slurry with the catalyst solution in a line prior to further mixing in a mixing location (e.g., a static mixer or mixing block). In this case, the static mixer or mixing block may continue to function properly as a mixing location due to the increased mixing time generated upstream thereof. Fig. 2 is a block schematic diagram of a gas phase reactor system 200 in which mixing of catalyst slurry and catalyst solution may be performed in-line upstream of a mixing unit 210, which mixing unit 210 may advantageously be or may comprise equipment that is a static mixer or mixing block, providing the possibility of significantly simpler equipment than a mechanically stirred mixing tank.

As shown in fig. 2, catalyst slurry is again provided from the first vessel 102 into line 104 and catalyst solution is again provided from the second vessel 106 into line 108. Instead of being supplied directly to the mixing unit 210, at least a portion of the catalyst solution in line 108 is transferred via line 116 (i.e., a "jump line") to line 104, wherein premixing of the catalyst slurry and catalyst solution may be performed in the downstream portion 104a of line 104 prior to entering the static mixer or mixing block 210. Optionally, all of the catalyst solution in line 108 need not be transferred to line 104 via line 116, and a portion of the catalyst solution may alternatively be directed to mixing unit 210. The downstream portion 104a includes the portion of the line 104 between the mixing unit 210 and the junction of the line 116 and the line 104. A slurry pump (not shown in fig. 2) may be located immediately upstream of the downstream portion 104a to maximize contact time in the downstream portion 104 a. In a non-limiting example, the catalyst slurry and catalyst solution can have a contact time of at least about 5 minutes (or at least about 6 minutes, such as at least about 7 minutes) within the downstream portion 104a, and the contact time can be further adjusted by selecting the location at which the line 116 intersects the line 104. The total (combined) contact time of the catalyst slurry and the catalyst solution in the downstream portion 104a and the mixing unit 210 may be at least about twice the total (combined) contact time obtained in the absence of the downstream portion 104a of the line 104 (e.g., when the catalyst slurry and the catalyst solution are directly introduced into the mixing unit 210), and/or the total contact time may be increased by at least about 4 minutes relative to the total contact time obtained in the absence of the downstream portion 104a of the line 104 (e.g., when the catalyst slurry and the catalyst solution are directly introduced into the mixing unit 210). In a more specific non-limiting example, when the downstream portion 104a of the line 104 is present, the total contact time within the downstream portion 104a and the mixing unit 210 can be at least about 6 minutes, or at least about 7 minutes (e.g., in the range of 6, 7 or 8 minutes to 7, 8, 9 or 10 minutes, with any of the foregoing lower limits to any of the foregoing upper limits contemplated, provided the upper limit is greater than the lower limit, e.g., 6-7 minutes).

After the modified catalyst slurry has been obtained from the mixing unit 210, the modified catalyst slurry may be transferred to the reactor 114 via line 112, as described above with reference to fig. 1 (again, it is noted that line 112 may be replaced with multiple parallel line(s) 112, as described above in connection with fig. 1). Optionally, one or more static mixers 115 can reside in line 112, which can provide additional mixing contact time if desired.

In yet another example, in-line mixing of the catalyst slurry and catalyst solution may be used in combination with a mechanically agitated mixing tank to provide even longer contact times (e.g., such that mixing unit 210 is or includes a mechanically agitated mixing tank, such as mixing tank 110 of fig. 1). An example of such a system is shown in fig. 3. Fig. 3 is a block schematic diagram of a gas phase reactor system 300 in which mixing of catalyst slurry and catalyst solution may be performed in-line upstream of a mechanically agitated mixing tank. The reactor system 300 may be obtained in the case where the mixing unit 210 of the reactor system 200 is in particular a mechanically stirred mixing tank with one or more impellers 111, such as the mixing tank 110 of the reactor system 100. Optionally, one or more static mixers or mixing blocks 120 may be additionally placed within line 104a to provide additional mixing contact time (if desired) upstream of the mechanically agitated mixing tank 110. In such embodiments, the contact time between the catalyst slurry and the catalyst solution in the downstream portion of line 104a may be as described above in connection with FIG. 2, for example, at least about 5,6, or 7 minutes, and the contact time in the stirred-tank 110 may be otherwise as described in connection with FIG. 1, for example, 30-40 minutes, or more generally from a lower limit of any of 20, 22, 25, 27, 28, or 30 minutes to an upper limit of any of about 30, 33, 35, 37, 38, 39, 40, 42, 45, or 50 minutes, wherein the total contact time is the sum of the line 104a contact time and the mixing tank 110 contact time.

The modified catalyst slurry may be introduced into the polymerization reactor via a single line in contact with the polymerization reactor fluid or via two or more lines, e.g., 2,3,4 or more lines, in contact with the polymerization reactor fluid. It is also contemplated that multiple modified catalyst slurries having different compositions may be introduced via two or more lines in fluid contact with the polymerization reactor. Such lines may include dedicated equipment for transporting one or more modified catalyst slurries through the line and into the polymerization reactor. Examples of such specialized equipment include, but are not limited to, pinch valves, nozzles (e.g., spray nozzles and solids flow nozzles), temperature controllers, and the like, and any combination thereof. Dedicated equipment can be used to control the uniformity of the catalyst entering the reactor. The line(s) into the polymerization reactor may be temperature controlled upstream of the dedicated equipment or within the equipment itself. Temperature control can help to adjust the viscosity of the modified catalyst slurry and limit temperature variations within the reactor due to one or more modified catalyst slurries entering the polymerization reactor at different rates. When multiple lines are present, each line may employ independent flow control and/or independent temperature control operations.

More generally, for overview, the modified catalyst slurry and one or more olefins and other potential streams may be introduced into a polymerization reactor, preferably a gas phase reactor, more preferably a fluidized bed gas phase reactor. The modified catalyst slurry may be obtained by combining an initial catalyst slurry comprising a supported catalyst comprising at least one catalyst compound with a catalyst solution comprising a first catalyst compound already comprised on the supported catalyst and/or a second catalyst compound not already comprised on the supported catalyst. The supported catalyst may comprise, in addition to the at least one catalyst compound, at least one activator supported on a support material. The catalyst slurry and the catalyst solution may each comprise a carrier liquid suitable for transporting the supported catalyst and the catalyst compound(s) therein, and wherein contact between the supported catalyst of the catalyst slurry and the catalyst compound(s) of the catalyst solution may occur. The carrier liquids in the catalyst slurry and the catalyst solution may be the same or different. By contacting the catalyst slurry with the catalyst solution, different catalyst compounds may be introduced onto the support material and/or the loading of at least one catalyst compound on the support material may be increased. Upon contacting the activator on the support material, a modified catalyst slurry having a regulated activity for carrying out the polymerization reaction may be obtained. In a non-limiting example, the modified catalyst slurry may be less prone to sheeting during polymerization, which is a direct result of the increased contact time between the catalyst slurry and the catalyst solution provided by the disclosure herein. The contact time may be further selected to reduce the extent of polymer sheeting to a desired extent.

Thus, some methods for increasing the contact time between a catalyst slurry and a catalyst solution according to the present disclosure may include providing a catalyst slurry comprising a supported catalyst comprising a support material, at least one catalyst compound, and at least one activator, introducing the catalyst slurry into a first line in fluid communication with a mechanically stirred mixing tank, introducing at least a first portion of a catalyst solution into a second line in fluid communication with the mechanically stirred mixing tank, the catalyst solution comprising a first catalyst compound that has been contained on the supported catalyst or a second catalyst compound that is different from the first catalyst compound and that is not contained on the supported catalyst, contacting the catalyst slurry with the catalyst solution in the mechanically stirred mixing tank to obtain a modified catalyst slurry from the mechanically stirred mixing tank, the modified catalyst slurry comprising a modified supported catalyst, the modified supported catalyst comprising the modified catalyst incorporating the first catalyst compound or the second catalyst compound from the catalyst solution, and fluidizing the catalyst slurry in a gas phase reactor under fluidized bed polymerization conditions.

In some or other embodiments, a method for increasing the contact time between a catalyst slurry and a catalyst solution according to the present disclosure may include providing a catalyst slurry comprising a supported catalyst comprising a support material, at least one catalyst compound, and at least one activator, introducing the catalyst slurry into a line in fluid communication with a mixing unit, introducing at least a first portion of a catalyst solution into the line upstream of the mixing unit, the catalyst solution comprising a first catalyst compound that has been included on the supported catalyst or a second catalyst compound that is different from the first catalyst compound and has not been included on the supported catalyst, contacting the catalyst slurry with the catalyst solution in the line and in the mixing unit to obtain a modified catalyst slurry from the mixing unit, the modified catalyst slurry comprising a modified supported catalyst that incorporates the first catalyst compound or the second catalyst compound from the catalyst solution, and fluidizing the catalyst slurry in a gas phase reactor under fluidized bed polymerization conditions.

As described above in connection with fig. 2 and 3, to increase the mixing efficiency (i.e., increase the contact time of the catalyst-containing mixture) prior to polymerization, the catalyst-containing mixture may be further contacted in-line upstream of the mixing unit by utilizing a jumper line. The jumper line may comprise a pipe or conduit in which at least a portion of the catalyst-containing mixture is diverted for premixing upstream of a mixing unit (e.g., a static mixer or mixing block, or even a mechanically agitated mixing tank). For example, the jumper line may facilitate a contact time of about 4, 5, or 6 minutes to about 6, 7, 8, 9, or 10 minutes between the catalyst-containing mixtures prior to entering the mixing unit.

When a jumper line is used, in one or more aspects, the mixing unit may comprise a static mixer, a mixing block, a mechanically agitated mixing tank, or any combination thereof. When a mechanically agitated mixing tank is used instead of a static mixer or mixing block, the contact time of the catalyst-containing mixture can be increased to about 30 minutes to about 40 minutes, or about 30 minutes to about 35 minutes, or about 35 minutes to about 40 minutes, plus the increased in-line contact time provided by the jumper line (e.g., 35, 36, or 37 minutes to 45, 46, 47, 48, 49, or 50 minutes in total). In one or more aspects, such as those according to fig. 1 described above, a mechanically agitated mixing tank may be used without a jumper line. Similar contact times between the catalyst-containing mixtures in the mechanically agitated mixing tank can be utilized.

The implementation of a jumper-on line, a mechanically agitated mixing tank, or a combination thereof can significantly reduce the amount of polymer sheeting in the polymerization reactor. For example, the polymer sheeting rate in the polymerization reactor may be 0.3% or less. In various embodiments, the polymer sheeting rate may be 0.3%, 0.27%, 0.25%, 0.23%, 0.2%, 0.17%, 0.15%, 0.13%, 0.1%, 0.09%, 0.8%, 0.07%, 0.06%, 0.05%, or 0.04%. Polymer sheeting rate refers to the mass percent of the sheet polymer produced relative to the total amount of polymer produced over a given length of time. The reduction in polymer sheeting rate can reduce the sheeting removal frequency downstream of the reactor. The accumulated polymer sheeting may not need to be removed from the collection box in communication with the polymerization reactor, for example, for up to 48 hours, or up to about 36 hours, or up to about 24 hours, or up to about 12 hours, or up to about 6 hours.

Catalyst slurry, catalyst solution and modified catalyst slurry

The catalyst slurry and modified catalyst slurry may comprise at least a carrier liquid and at least one catalyst compound on a supported catalyst. Optionally, the catalyst slurry may further comprise one or more waxes, mineral oils, induced condensing agents, or any combination thereof. In some embodiments, the carrier liquid may be or may include, but is not limited to, one or more mineral oils and/or one or more waxes, optionally in further combination with an induced condensing agent.

It should also be noted that some of the components present within the polymerization reactor may be fed into the reactor via a modified catalyst slurry (e.g., optionally induced condensing agent, carrier fluid such as nitrogen, etc.), or may additionally or alternatively be fed into the reactor via other means. For example, the induced condensing agents in gas phase polymerization processes, particularly fluidized bed gas phase polymerization processes, may be provided to the process in a recycle gas flowing up through the fluidized bed in the polymerization reactor, or they may be provided in other streams that are not modified catalyst slurries or recycle gases. Recycle gas may refer to a gas stream comprising an olefinic feed that is circulated through the reactor and replenished with additional olefin, if desired.

In some embodiments, the catalyst slurry or modified catalyst slurry may comprise 1wt%, 5 wt%, 8 wt%, or 10wt% to 15 wt%, 20 wt%, 25 wt%, 30wt%, 35 wt%, or 40 wt% solids, based on the total weight of the catalyst slurry or modified catalyst slurry. The solids include the catalyst compound(s), support material, activator, and any other solid component(s), if present. If present in the carrier liquid, the wax is considered a liquid component rather than a solid component. For example, if the catalyst slurry or modified catalyst slurry comprises a first catalyst, a second catalyst, a support, an activator, and a carrier liquid comprising mineral oil and wax, then the solid component comprises the first and second catalysts, the support, and the activator, and the liquid component comprises the mineral oil and wax.

The modified catalyst slurry may include a first catalyst compound capable of producing a high molecular weight polymer and a second catalyst compound capable of producing a low molecular weight polymer. In other words, the first catalyst compound may be a catalyst compound that primarily prepares high molecular weight polymer chains, and the second catalyst compound primarily prepares low molecular weight polymer chains, which may depend on the catalyst structure and polymerization reaction performed under specified polymerization conditions. Thus, in some examples, the polymer product produced by the modified catalyst slurry under polymerization conditions may comprise both high molecular weight polymer and low molecular weight polymer. The two catalyst compounds may be present in the modified catalyst slurry in a molar ratio of the first catalyst compound to the second catalyst compound of from 99:1 to 1:99, from 90:10 to 10:90, from 85:15 to 15:85, from 75:25 to 25:75, from 60:40 to 40:60, from 55:45 to 45:55. In some embodiments, the first catalyst compound and/or the second catalyst compound may also be added to the catalyst slurry from the catalyst solution as a trim catalyst to adjust the molar ratio of the first catalyst compound to the second catalyst compound. In at least one embodiment, the first catalyst compound and the second catalyst compound may each be a metallocene catalyst, as described further below.

The term "slurry catalyst" or "catalyst slurry" each refers to a contact product comprising a dispersed supported catalyst comprising at least one catalyst compound, carrier liquid and activator, and optionally a co-activator, supported on a carrier. In particular embodiments, the slurry catalyst may comprise two catalyst compounds, such as two metallocene catalyst compounds, particularly after formation of the modified catalyst slurry. For example, the modified slurry catalyst can comprise a supported catalyst comprising a first metallocene and a second metallocene that are each different from one another in at least one structural aspect. Additional disclosure regarding suitable catalyst compounds is provided further below.

As just described, one or more Induced Condensing Agents (ICAs) may be introduced into the reactor, such ICAs may increase the rate of production of the polymer product. ICA may be present in the catalyst slurry, the catalyst solution, or a modified catalyst slurry resulting from contacting the catalyst slurry with the catalyst solution. Or at least a portion of the ICA may be combined with the modified catalyst slurry in a line leading from the mixing apparatus to the reactor (e.g., in line(s) 112 as illustrated in fig. 1-3), or the ICA may be introduced into the reactor independent of the catalyst slurry. ICA can condense under polymerization conditions within the polymerization reactor. Introducing ICA into a reactor is commonly referred to as operating the reactor in "condensed mode". ICA may be non-reactive during polymerization, but the presence of ICA may increase the rate of production of the polymer product. In some embodiments, the ICA reagent may be or may include, but is not limited to, one or more alkanes. Exemplary alkanes may be or include, but are not limited to, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, isohexane, n-heptane, n-octane, or any mixture thereof. Further details regarding ICAs can be found in U.S. Pat. Nos. 5,352,749, 5,405,922, 5,436,304, and 7,122,607, and International patent application publication No. WO 2005/113615 (A2). As noted, such ICA(s) may be added in-line to the modified catalyst slurry, which may be the primary source of ICA provided to the reactor, or any other ICA introduced separately to the reactor may be added, such as via recycle gas introduced to the reactor. The induced condensing agent may be introduced into the modified catalyst slurry at a rate of about 0.4kg/hr, 1kg/hr, 5kg/hr, or 8kg/hr to 11kg/hr, 23kg/hr, or 45kg/hr per line or at an average rate of about 0.4kg/hr, 1kg/hr, 5kg/hr, or 8kg/hr to 11kg/hr, 23kg/hr, or 45kg/hr per line when multiple lines are used.

When the catalyst slurry or modified catalyst slurry further comprises an induced condensing agent, the induced condensing agent may comprise from 30 wt.% to 90 wt.% of the catalyst slurry or modified catalyst slurry, for example from 30 wt.%, 35 wt.%, 40 wt.%, 45 wt.% or 50 wt.% to 60 wt.%, 70 wt.%, 80 wt.% or 90 wt.% of the catalyst slurry or modified catalyst slurry. In some embodiments, when the catalyst slurry or modified catalyst slurry includes mineral oil and wax in addition to the induced condensing agent, the mineral oil may comprise from a lower limit of 8, 15, 20, or 25 wt% to an upper limit of 40, 50, 60, or 68 wt% of the catalyst slurry or modified catalyst slurry, the wax may comprise from a lower limit of 2, 5, or 7 wt% to an upper limit of 10, 12, or 15 wt% of the catalyst slurry or modified catalyst slurry, and the induced condensing agent may comprise from a lower limit of 30, 40, 45, or 50 wt% to an upper limit of 60, 70, 80, or 90 wt% of the catalyst slurry or modified catalyst slurry, each based on the total mass of the catalyst slurry or modified catalyst slurry.

Waxes, if present, may increase the viscosity of the catalyst-containing mixture. The term "wax" as used herein includes petrolatum, also known as petrolatum or petroleum wax. Petroleum waxes include paraffin waxes and microcrystalline waxes, which include slack wax (slackwax) and scale wax (scale wax). Commercially available waxes include SONOParaffin, e.g. SONOs obtainable from Sonneborn, LLC4 And SONOIn at least one embodiment, the wax (if present) can have a density (at 100 ℃) of 0.7g/cm ³、0.73g/cm³ or 0.75g/cm ³ to 0.87g/cm ³、0.9g/cm³ or 0.95g/cm ³. The wax (if present) may have a 100 ℃ kinematic viscosity of 5cSt, 10cSt, or 15cSt to 25cSt, 30cSt, or 35 cSt. The wax (if present) may have a melting point of 25 ℃, 35 ℃, or 50 ℃ to 80 ℃, 90 ℃, or 100 ℃. The wax (if present) may have a boiling point of 200 ℃ or more, 225 ℃ or more, or 250 ℃ or more.

It should be understood that the term "wax" also refers to or otherwise includes any wax that is not considered a petroleum wax, including animal waxes, vegetable waxes, mineral fossil or earth waxes (earth wax), olefinic polymers and polyol ether-esters, chlorinated naphthalenes, and hydrocarbon-type waxes. Animal waxes may include beeswax, lanolin, shellac wax (shellac wax) and chinese insect wax (CHINESE INSECT wax). Vegetable waxes may include carnauba wax, candelilla wax, bayberry wax (bayberry), and sugar cane wax (sugarcane). The paraffin wax or earth wax may include ceresin (ozocerite), ceresin (ceresin) and Meng Tan (montan). Olefinic polymers and polyol ether-esters include polyethylene glycol and methoxypolyethylene glycol. Hydrocarbon-type waxes include waxes produced via fischer-tropsch synthesis.

In some embodiments, the catalyst slurry, catalyst solution, or modified catalyst slurry may be free of any wax having a melting point greater than or equal to 25 ℃. In other embodiments, the catalyst slurry, catalyst solution, or modified catalyst slurry may comprise +.3% by weight, +.2.5% by weight, +.2% by weight, +.1.5% by weight, +.1% by weight, +.0.9% by weight, +.0.8% by weight, +.0.7% by weight, +.0.6% by weight, +.0.5% by weight, +.0.4% by weight, +.0.3% by weight, +.0.2% by weight, or +.1% by weight of any wax having a melting point of +.25 ℃ based on the total mass of the catalyst slurry, catalyst solution, or modified catalyst slurry.

In various embodiments, an alkyl aluminum, an ethoxylated alkyl aluminum, an aluminoxane, an antistatic agent (such antistatic agents are mentioned in paragraphs [0078] - [0082] of WO 2022/174202) or a borate activator, such as a C ₁ to C ₁₅ alkyl aluminum (e.g., triisobutyl aluminum, trimethyl aluminum, etc.), a C ₁ to C ₁₅ ethoxylated alkyl aluminum or methyl aluminoxane, ethyl aluminoxane, isobutyl aluminoxane, modified aluminoxane, etc., may be added in-line to the modified catalyst slurry. For example, alkylate, antistatic agent, borate activator, and/or alumoxane may be added directly in-line from the vessel to the modified catalyst slurry. Additional alkylate, antistatic agent, borate activator, and/or aluminoxane may be present in an amount of 1ppm, 10ppm, 50ppm, 75ppm, or 100ppm to 200ppm, 300ppm, 400ppm, or 500 ppm. In some embodiments, an optional carrier fluid such as molecular nitrogen, argon, ethane, propane, etc. may be added in-line to the modified catalyst slurry. A carrier fluid, such as molecular nitrogen, may be introduced via the lines at a rate of about 0.4kg/hr, 1kg/hr, 5kg/hr, or 8kg/hr to 11kg/hr, 23kg/hr, or 45kg/hr per line (or at an average rate of about 0.4kg/hr, 1kg/hr, 5kg/hr, or 8kg/hr to 11kg/hr, 23kg/hr, or 45kg/hr per line when multiple lines are used). In other embodiments, the carrier fluid may be introduced via the lines at a rate of about 5kg/hr, 7kg/hr, 9kg/hr, or 10kg/hr to 11kg/hr, 13kg/hr, or 15kg/hr per line or at an average rate of about 5kg/hr, 7kg/hr, 9kg/hr, or 10kg/hr to 11kg/hr, 13kg/hr, or 15kg/hr per line when multiple lines are used.

In some embodiments (not directly shown in fig. 1,2, or 3), a carrier fluid (e.g., molecular nitrogen, monomer, or other material) may be introduced into the modified catalyst slurry after mixing the catalyst solution and the catalyst slurry. The introduction may be along a line leading to the gas phase polymerization reactor or in an injection nozzle, which may comprise a support tube which may at least partially surround the injection nozzle. The modified catalyst slurry may enter the reactor through an injection nozzle. In various embodiments, the injection nozzle may atomize the catalyst-containing mixture. Any number of suitable conduit sizes and configurations may be used to atomize and/or inject the slurry/solution mixture.

In some configurations, the carrier fluid may be directly or indirectly separated from the recycle gas (e.g., all or a portion of the recycle gas) or otherwise sourced. In this case, in case a recycle gas is used as carrier fluid, it will be appreciated by the person skilled in the art that such recycle gas may also comprise an induced condensing agent. The recycle gas may comprise at least a portion of the polymerization feed recycled through the gas phase polymerization reactor.

In some embodiments, the modified catalyst slurry may include 1 wt%, 5wt%, 10wt%, or 15 wt% to 25wt%, 30 wt%, 35 wt%, or 40wt% of one or more catalyst compounds, based on the total weight of the modified catalyst slurry. The aforementioned weight percentages exclude the support material on which the catalyst is disposed. In such embodiments, the total amount of modified catalyst slurry introduced into the reactor may be at a flow rate of 0.1 kg/hr/cubic meter of polymerization reactor volume, 0.11 kg/hr/cubic meter of polymerization reactor volume, 0.12 kg/hr/cubic meter of polymerization reactor volume, 0.13 kg/hr/cubic meter of polymerization reactor volume, or 0.14 kg/hr/cubic meter of polymerization reactor volume to 0.2 kg/hr/cubic meter of polymerization reactor volume, 0.3 kg/hr/cubic meter of polymerization reactor volume, 0.4 kg/hr/cubic meter of polymerization reactor volume, or 0.5 kg/hr/cubic meter of polymerization reactor volume.

In some embodiments, to facilitate particle formation in the reactor, a nucleating agent such as silica, alumina, fumed silica (fumed silica), or other suitable particulate material may be added directly to the reactor. Or the nucleating agent may be present in the catalyst solution, catalyst slurry and/or modified catalyst slurry, optionally with further introduction of the nucleating agent into the reactor also taking place. Advantageously, in the disclosure herein, the nucleating agent may be optional, but may be included if desired. Preferably, the nucleating agent is removed from the catalyst solution and catalyst slurry and/or introduced into the modified catalyst slurry in line(s) downstream of any mixing unit (mechanically agitated mixing tank, static mixer, mixing block, etc.), if any, when mixing the catalyst solution and catalyst slurry. For embodiments that do not include a nucleating agent, it has been found that a high polymer bulk density (e.g., 0.4g/cm ³ or greater) can be obtained that is greater than the bulk density of the polymer formed by conventional finishing methods. In addition, when a metallocene catalyst or other similar catalyst is used in the gas phase reactor, oxygen or fluorobenzene can be added directly to the reactor or added in-line to the gas stream (including carrier fluid) to control the rate of polymerization (polymerization rate). Thus, when a metallocene catalyst (which is oxygen or fluorobenzene sensitive) is used in combination with another catalyst (which is not oxygen sensitive) in a gas phase reactor, oxygen can be used to alter the metallocene polymerization rate relative to the polymerization rate of the other catalyst. For example, WO 1996/009328 discloses the addition of water or carbon dioxide to a gas phase polymerization reactor for similar purposes.

Catalyst compound

Once the modified supported catalyst is formed, the methods of the present disclosure may generally be used with any catalyst system that includes at least one catalyst compound on a support, preferably two or more catalyst compounds on a support. In a particular example, the supported catalyst in the catalyst slurry can contain a first catalyst compound on a support, and a second catalyst compound different from the first catalyst compound can be delivered from the catalyst solution to the catalyst slurry to form a modified catalyst slurry according to the disclosure herein.

As a specific example, the catalyst compound may include one or more metallocenes. In some embodiments, the catalyst may include first and second catalyst compounds that are at least a first metallocene and a second metallocene, wherein the first and second metallocenes have different chemical structures from each other. The metallocene may include a structure having one or more Cp ligands (cyclopentadienyl and ligands isolobal (isolobal) to cyclopentadienyl) bonded to at least one group 3 to group 12 metal atom and one or more leaving group(s) bonded to the at least one metal atom.

Suitable metallocene catalysts may include those described in U.S. patent application publications 2019/019413 and 2019/019417, which are incorporated herein by reference. Also suitable are catalyst systems using a mixture of two metallocene catalysts, such as those described in U.S. patent application publication 2020/007437, for example a mixture of (1) a biscyclopentadienyl hafnocene and (2) a zirconocene, for example an indenyl-cyclopentadienyl zirconocene. Additional details are provided below.

More particularly, the biscyclopentadienyl hafnocene may be one or more of the metallocenes according to formulae (A1) and/or (A2) described in US 2020/007147, for example those according to formula (A1) described in paragraphs [0069] - [0086] of US 2020/007147, or those according to formula (A2) described in paragraphs [0086] - [0101] of US 2020/007147, the description of which is incorporated herein by reference.

Specific examples of the hafnocene according to the formula (A1) include bis (n-propylcyclopentadienyl) hafnium dichloride, bis (n-propylcyclopentadienyl) hafnium dimethyl, bis (n-propylcyclopentadienyl) hafnium dichloride, bis (n-propylcyclopentadienyl, pentamethylcyclopentadienyl) hafnium dimethyl, bis (n-propylcyclopentadienyl, tetramethylcyclopentadienyl) hafnium dimethyl, bis (cyclopentadienyl) hafnium dichloride, bis (n-butylcyclopentadienyl) hafnium dimethyl and bis (1-methyl-3-n-butylcyclopentadienyl) hafnium dimethyl.

Particularly useful hafnocene compounds according to (A2) include one or more of the compounds listed in paragraph [0101] of US 2020/007437, which is also incorporated herein by reference, for example (for the simpler examples) racemic/meso Me ₂Si(Me₃SiCH₂Cp)₂HfMe₂, racemic Me ₂Si(Me₃SiCH₂Cp)₂HfMe₂, racemic/meso Ph ₂Si(Me₃SiCH₂Cp)₂HfMe₂, racemic/meso (CH ₂)₃Si(Me₃SiCH₂Cp)₂HfMe₂, racemic/meso (CH ₂)₄Si(Me₃SiCH₂Cp)₂HfMe₂; racemic/meso (C ₆F₅)₂Si(Me₃SiCH₂Cp)₂HfMe₂; racemic/meso (CH ₂)₃Si(Me₃SiCH₂Cp)₂ZrMe₂; racemic/meso Me ₂Ge(Me₃SiCH₂Cp)₂HfMe₂; racemic/meso Me ₂Si(Me₂PhSiCH₂Cp)₂HfMe₂; racemic/meso Ph₂Si(Me₂PhSiCH₂Cp)₂HfMe₂;Me₂Si(Me₄Cp)(Me₂PhSiCH₂Cp)HfMe₂ etc.).

Thus, in one particular example, the first catalyst compound on the support material may comprise a first metallocene that is a hafnocene, such as racemic/meso-dimethyl-silylbis [ ((trimethylsilyl) methyl) cyclopentadienyl ] hafnium. The second catalyst compound in the catalyst solution may comprise a second metallocene different from the first metallocene. The second metallocene may comprise a zirconocene, as described below.

Suitable catalyst compounds may include zirconocenes, for example according to formula (B) as described in paragraphs [0103] - [0113] of US 2020/007437, the description also being incorporated herein by reference. Specific examples of suitable zirconocenes may be any one or more of those listed in paragraph [0112] of US 2020/007437, for example: bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dimethyl, bis (tetrahydro-1-indenyl) zirconium dichloride, bis (tetrahydro-1-indenyl) zirconium dimethyl, bis (1-ethyl indenyl) zirconium rac/meso-bis (1-ethyl indenyl) zirconium dichloride, bis (1-ethyl indenyl) zirconium rac/meso-dimethyl, bis (1-methyl indenyl) zirconium rac/meso-bis (1-methyl indenyl) zirconium meso/meso-bis (1-methyl indenyl) zirconium bis (1-propyl indenyl) zirconium meso/meso-bis (1-propyl indenyl) zirconium, bis (1-propyl indenyl) zirconium rac/meso-bis (1-butyl indenyl) zirconium rac/meso-dimethyl bis (1-butyl indenyl) zirconium meso/meso-bis (1-butyl indenyl) zirconium meso/bis (1-butyl indenyl) zirconium meso-bis (1-methyl indenyl) zirconium meso-bis (1-propyl indenyl) zirconium meso-bis (1-ethyl indenyl) zirconium meso-bis (1-butyl indenyl) zirconium meso-bis (1-ethyl indenyl) zirconium, dimethyl- (1-methylindenyl) (pentamethylcyclopentadienyl) zirconium or a combination thereof.

Thus, in a particular example, the second catalyst compound can comprise a second metallocene that is a zirconocene, such as racemic/meso-dimethyl-bis (1-methylindenyl) zirconium.

As described above, the supported catalyst and/or modified supported catalyst may include one or more activators and/or supports in addition to one or more catalyst compounds. The term "activator" refers to any compound or combination of compounds that can activate a single site catalyst compound or component (e.g., by generating a cationic species of the catalyst component) either supported or unsupported. For example, this may include abstraction of at least one leaving group from the metal center of the single site catalyst compound/component. The activator may also be referred to as a "cocatalyst". For example, a supported catalyst or modified supported catalyst within a slurry catalyst or modified slurry catalyst mixture may include two or more activators (e.g., aluminoxanes and modified aluminoxanes) and at least one catalyst compound, such as a first catalyst compound and a second catalyst compound. In particular embodiments, the slurry catalyst or modified slurry catalyst may comprise at least one support, at least one activator, and at least two catalyst compounds. For example, the slurry may include at least one support, at least one activator, and two different catalyst compounds, which may be added alone or in combination to produce a slurry catalyst or a modified slurry catalyst. In some embodiments, a mixture of a support (e.g., silica) and an activator (e.g., aluminoxane) can be contacted with a catalyst compound, allowing for reaction, and thereafter the mixture can be contacted with another catalyst compound from a catalyst solution to form a modified supported catalyst within a modified catalyst slurry according to the disclosure herein.

The molar ratio of metal or non-coordinating anion in the activator to metal in the catalyst compound(s) in the slurry catalyst may be 1000:1 to 0.5:1, 300:1 to 1:1, 100:1 to 1:1, or 150:1 to 1:1. The support material for the supported catalyst may be any inert particulate support material known in the art including, but not limited to, silica, fumed silica, alumina, clay, talc or other support materials such as those disclosed above. In one embodiment, the supported catalyst may include silica and an activator, such as methylaluminoxane ("MAO"), modified methylaluminoxane ("MMAO"), and the like. Preferred activators generally include aluminoxane compounds, modified aluminoxane compounds, and ionizing anion precursor compounds that abstract reactive sigma-bonded metal ligands, cationize metal compounds, and provide charge-balancing non-coordinating or weakly coordinating anions. For example, suitable activators may include any of the aluminoxane activators and/or ionizing/non-coordinating anion activators described in paragraphs [0118] - [0128] of US 2020/007147, also incorporated herein by reference.

Suitable supports include, but are not limited to, active and inactive materials, synthetic or naturally occurring zeolites, and inorganic materials such as clays and/or oxides such as silica, alumina, zirconia, titania, silica-alumina, ceria, magnesia, or combinations thereof. In particular, the support may be silica-alumina, alumina and/or zeolite, in particular alumina. The silica-alumina may be naturally occurring or in the form of a gelatinous precipitate or gel comprising a mixture of silica and metal oxide. Suitable carriers may include any of the carrier materials described in paragraphs [0129] to [0131] of US 2020/007137, also incorporated herein by reference, wherein Al ₂O₃、ZrO₂、SiO₂ and combinations thereof are specifically noted.

Catalyst solution

The catalyst solution may include a solvent or diluent and only the catalyst compound(s), such as a metallocene, or may also include an activator. In particular examples, at least one catalyst compound in the catalyst solution may be unsupported. Preferably, the catalyst solution may be prepared by dissolving at least one catalyst compound and optionally an activator in a solvent or diluent. In some embodiments, the diluent or solvent may be an alkane, such as a C ₅ to C ₃₀ alkane or a C ₅ to C ₁₀ alkane. Cycloalkanes such as cyclohexane and aromatics such as toluene may also be used. Mineral oil may also be used as a diluent in place of or in addition to other alkanes such as one or more C ₅ to C ₃₀ alkanes. The mineral oil in the catalyst solution, if used, may have the same properties as the mineral oil that may be used to prepare the catalyst slurry.

The diluent or solvent used may be liquid and relatively inert under the polymerization conditions. In one embodiment, the diluent used in the catalyst solution may be different from the diluent used in the catalyst slurry. In another embodiment, the solvent used in the catalyst solution may be the same as the diluent, i.e., mineral oil(s) and any additional diluent used in the catalyst slurry. In some cases, hydrocarbon solvents may also be used as an induced condensing agent during the polymerization reaction.

If the catalyst solution includes both catalyst and activator, the ratio of metal or non-coordinating anion in the activator to metal in the catalyst solution may be 1000:1 to 0.5:1, 300:1 to 1:1, or 150:1 to 1:1. In various embodiments, the activator and catalyst may be present in the catalyst solution at up to about 90 wt%, up to about 50 wt%, up to about 20 wt%, for example up to about 10 wt%, up to about 5 wt%, at less than 1 wt% or 100ppm to 1 wt%, based on the weight of the diluent, activator, and catalyst. The one or more activators (if used) in the catalyst solution may be the same as or different from the one or more activators present in the catalyst slurry on the supported catalyst.

Polymerization conditions and polyolefin products

Once the modified catalyst slurry is produced according to the disclosure above, the modified catalyst slurry can be fed into the polymerization reaction under suitable polymerization conditions in combination with an olefin feed to obtain a polyolefin. In a non-limiting example, the olefin feed may comprise at least one alpha-olefin to provide a polyolefin homo-or copolymer.

Monomers useful herein include substituted or unsubstituted C ₂ to C ₄₀ alpha-olefins, such as C ₂ to C ₂₀ alpha-olefins, such as C ₂ to C ₁₂ alpha-olefins, such as ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene and isomers thereof. In at least one embodiment, the monomers may comprise ethylene and one or more optional comonomers selected from C ₃ to C ₄₀ olefins, such as C ₄ to C ₂₀ olefins, such as C ₆ to C ₁₂ olefins. Suitable C ₄ to C ₄₀ olefin monomers may be linear, branched or cyclic. The C ₄ to C ₄₀ cyclic olefins may be strained (strained) or unstrained (unstrained), monocyclic or polycyclic, and may optionally include heteroatoms and/or one or more functional groups. In at least one embodiment, the monomers may comprise ethylene and optionally a comonomer, which may include one or more C ₃ to C ₄₀ olefins, such as C ₄ to C ₂₀ olefins, such as C ₆ to C ₁₂ olefins.

In some embodiments, the C ₂ to C ₄₀ alpha-olefin monomer and optional comonomer(s) include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, norbornene, norbornadiene, dicyclopentadiene, cyclopentene, cycloheptene, cyclooctene, cyclooctadiene, cyclododecene, 7-oxanorbornene, 7-oxanorbornadiene, substituted derivatives and isomers thereof, such as hexene, heptene, octene, nonene, decene, dodecene, cyclooctene, 1, 5-cyclooctadiene, 1-hydroxy-4-cyclooctene, 1-acetoxy-4-cyclooctene, 5-methylcyclopentene, cyclopentene, dicyclopentadiene, norbornene, norbornadiene and corresponding homologs and derivatives thereof, such as norbornene, norbornadiene and dicyclopentadiene.

In at least one embodiment, the one or more dienes may be present in the polymer product in an amount up to 10 wt%, such as from 0.00001 wt% to 1.0 wt%, such as from 0.002 wt% to 0.5 wt%, such as from 0.003 wt% to 0.2 wt%, based on the total weight of the composition. In at least one embodiment, 500ppm or less of diene is added to the polymerization, such as 400ppm or less, such as 300ppm or less. In other embodiments, at least 50ppm diene, or 100ppm or more, or 150ppm or more, is added to the polymerization.

Diene monomers include any hydrocarbon structure having at least two unsaturated bonds, such as C ₄ to C ₃₀, wherein at least two of the unsaturated bonds are readily incorporated into the polymer by stereospecific or non-stereospecific catalyst(s). The diene monomer may be selected from alpha, omega-diene monomers (i.e., divinyl monomers). Diene monomers are linear divinyl monomers, for example, those having from 4 to 30 carbon atoms. Examples of dienes include butadiene, pentadiene, hexadiene, heptadiene, octadiene, nonadiene, decadiene, undecadiene, dodecadiene, tridecadiene, tetradecadiene, pentadecadiene, hexadecadiene, heptadecadiene, octadecadiene, nonadecadiene, icosapiene, heneicosapiene, docosyl, tricosyl, tetracosyl, pentacosyl, hexacosadiene, heptacosadiene, octacosadiene, nonacosadiene, triacontadiene, particularly preferred dienes include 1, 6-heptadiene, 1, 7-octadiene, 1, 8-nonadiene, 1, 9-decadiene, 1, 10-undecadiene, 1, 11-dodecadiene, 1, 12-tridecadiene, 1, 13-tetradecadiene and low molecular weight polybutadiene (Mw less than 1000 g/mol). Cyclic dienes include cyclopentadiene, vinyl norbornene, norbornadiene, ethylidene norbornene, divinylbenzene, dicyclopentadiene or diolefins containing higher rings with or without substituents at each ring position.

The temperature within the reactor may be greater than 30 ℃, greater than 40 ℃, greater than 50 ℃, greater than 90 ℃, greater than 100 ℃, greater than 110 ℃, greater than 120 ℃, greater than 150 ℃ or higher. In general, the reactor may be operated at a suitable temperature in view of the sintering temperature of the polymer product being produced within the reactor. Thus, in one embodiment, the upper temperature limit may be the melting temperature of the polymer product produced within the reactor. However, higher temperatures may result in narrower molecular weight distributions, which may be further improved by the addition of catalysts or other cocatalysts.

In some embodiments, hydrogen may be used in the polymerization process to help control or otherwise adjust the final properties of the polyolefin, as described in "Polypropylene Handbook", pages 76-78 (Hanser Publishers, 1996). With certain catalyst systems, increasing the concentration (partial pressure) of hydrogen can increase the flow index, e.g., melt index, of the polyethylene polymer. The melt index may thus be affected by the hydrogen concentration. The amount of hydrogen in the polymerization can be expressed as a molar ratio relative to the total polymerizable monomer, e.g., ethylene, or a blend of ethylene and hexene or propylene.

The amount of hydrogen used in the polymerization process may be that necessary to achieve the desired melt index of the final polyolefin polymer. For example, the molar ratio of hydrogen to total monomer (H ₂: monomer) may be 0.0001 or greater, 0.0005 or greater, or 0.001 or greater. In addition, the molar ratio of hydrogen to total monomer (H ₂: monomer) may be 10 or less, 5 or less, 3 or less, or 0.10 or less. The range of molar ratios of hydrogen to monomer may include any combination of any upper molar ratio limit with any lower molar ratio limit described herein. The amount of hydrogen in the reactor at any time may be up to 5,000ppm, in another embodiment up to 4,000ppm, in another embodiment up to 3,000ppm, or from 50ppm to 5,000ppm, or from 50ppm to 2,000ppm. The amount of hydrogen in the reactor may be 1ppm, 50ppm or 100ppm to 400ppm, 800ppm, 1,000ppm, 1,500ppm or 2,000ppm based on weight. In addition, the ratio of hydrogen to total monomer (H ₂: monomer) may be 0.00001:1 to 2:1,0.005:1 to 1.5:1, or 0.0001:1 to 1:1. One or more reactor pressures in a gas phase process (single stage or two or more stages) may vary between 690kPa, 1,379kPa or 1,724kPa to 2,414kPa, 2,759kPa or 3,447 kPa.

The reactor is capable of producing greater than 10 kg/hr (kg/hr), greater than 455kg/hr, greater than 4,540kg/hr, greater than 11,300kg/hr, greater than 15,900kg/hr, greater than 22,700kg/hr, or greater than 29,000kg/hr to 45,500kg/hr, 70,000kg/hr, 100,000kg/hr, or 150,000kg/hr of polymer.

In some embodiments, the polymer product may have a melt index ratio (I _21.6/I_2.16) of 10 to less than 300, or in many embodiments 20 to 66. Melt index (I _2.16) can be measured according to ASTM D-1238-13, condition E (190 ℃,2.16 kg), and is also referred to as "I ₂ (190 ℃ C./2.16 kg)". Melt index (I _21.6) can be measured according to ASTM D-1238-13, condition F (190 ℃,21.6 kg), and is also referred to as "I _21.6 (190 ℃ C./21.6 kg)".

In some embodiments, the polymer product may have a density of 0.89g/cm ³、0.90g/cm³ or 0.91g/cm ³ to 0.95g/cm ³、0.96g/cm³ or 0.97g/cm ³. The density can be determined according to ASTM D-792-20. In some embodiments, the polymer product may have a bulk density (a bulk density) of 0.25g/cm ³ to 0.5g/cm ³. For example, the bulk density of the polymer may be 0.30g/cm ³、0.32g/cm³ or 0.33g/cm ³ to 0.40g/cm ³、0.44g/cm³ or 0.48g/cm ³. Bulk density can be measured according to ASTM D-1895-17 method B.

In some embodiments, the polymerization process may include contacting one or more olefin monomers with a modified catalyst slurry, which may include mineral oil and supported catalyst. The one or more olefin monomers may be ethylene and/or propylene, and the polymerization process may include heating the one or more olefin monomers and the catalyst system to 70 ℃ or higher to form an ethylene polymer, a propylene polymer, or an ethylene-propylene copolymer.

In at least one embodiment, the catalysts and methods disclosed herein are capable of producing ethylene polymers having a weight average molecular weight (Mw) of 40,000g/mol, 70,000g/mol, 90,000g/mol, or 100,000g/mol to 200,000g/mol, 300,000g/mol, 600,000g/mol, 1,000,000g/mol, or 1,500,000 g/mol. Mw may be measured using Gel Permeation Chromatography (GPC). For GPC data, the Differential Refractive Index (DRI) method is preferred for Mn, while Light Scattering (LS) is preferred for Mw and Mz. GPC can be performed on a Waters 150C GPC instrument with a DRI detector. GPC columns can be calibrated by running a series of narrow polystyrene standard samples. The molecular weight of polymers other than polystyrene is generally calculated by using the Mark Houwink coefficient of the polymer in question.

The ethylene polymer may have a Melt Index (MI) of 0.2g/10min or greater, such as 0.4g/10min or greater, 0.6g/10min or greater, 0.7g/10min or greater, 0.8g/10min or greater, 0.9g/10min or greater, 1.0g/10min or greater, 1.1g/10min or greater, or 1.2g/10min or greater. In some embodiments, the upper limit of the MI of the ethylene polymer may be any of 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, or 5.5g/10 min. In some or other embodiments, the ethylene polymer may have a melt index of up to about 25g/10min, or up to about 50g/10min, or up to about 100g/10 min.

"Catalyst productivity" is a measure of how many grams of polymer (P) were produced over a period of T hours using a polymerization catalyst comprising W g catalyst (cat) and can be expressed in terms of P/(T W) and in units gPgcat ^-1hr^-1. In at least one embodiment, the productivity of the catalysts disclosed herein can be at least 50gPgcat ^-1hr^-1 or higher, such as 500gPgcat ^-1hr^-1 or higher, such as 800gPgcat ^-1hr^-1 or higher, such as 5,000g pgcat ^-1hr^-1 or higher, such as 6,000g pgcat ^-1hr^-1 or higher.

Although a gas phase polymerization process is described above, it should be understood that other polymerization processes known in the art may also be used to prepare the polymer product. In some embodiments, any suspension, homogeneous, bulk, solution, slurry, and/or other gas phase polymerization process known in the art may be used. Such a process may be operated in batch, semi-batch or continuous mode. A homogeneous polymerization process is defined as a process in which at least about 90% by weight of the product is soluble in the reaction medium. Bulk processes are defined as processes in which the monomer concentration in all the feed to the reactor is 70% by volume or more. Or the solvent or diluent is not present or added to the reaction medium (except in small amounts used as a support for the catalyst system or other additives, or in amounts typically found with monomers, such as propane in propylene).

In some embodiments, the polymerization process may be a slurry polymerization process, preferably a continuous slurry loop polymerization process. A single slurry loop reactor may be used, or multiple reactors in parallel or series (although to achieve a unimodal molecular weight distribution, it may be preferable to use a single reactor, or to use the same catalyst, feed and reaction conditions in multiple reactors, e.g., in parallel, so that the polymer product is considered to be produced in a single reaction step). The term "slurry polymerization process" as used herein refers to a polymerization process in which a supported catalyst is used and monomer is polymerized on the supported catalyst particles in a liquid medium (comprising, for example, an inert diluent and unreacted polymerizable monomer) such that a two-phase composition comprising polymer solids and liquid is circulated within the polymerization reactor. In general, a slurry tank or a slurry loop reactor may be used, with a slurry loop reactor being preferred in certain embodiments herein. In such a process, the reaction diluent, dissolved monomer(s) and catalyst may be circulated in a loop reactor, wherein the pressure of the polymerization reaction is higher. The solid polymer produced is also circulated in the reactor. The slurry of polymer and liquid medium may be collected in one or more settling legs of a slurry loop reactor from which the slurry is periodically discharged to a flash chamber, wherein the mixture may be flashed to a relatively low pressure, and as an alternative to settling legs, a single point discharge process may be used to move the slurry to the flash chamber in other examples. The flash evaporation results in substantially complete removal of the liquid medium from the polymer, and the vaporized polymerization diluent (e.g., isobutane) may then be recompressed to condense the recovered diluent into a liquid form suitable for recycling to the reactor as a liquid diluent.

Slurry polymerization processes may include those described in U.S. Pat. No. 6,204,344. Other non-limiting examples of slurry processes include continuous loop or stirred tank processes. Further, other examples of slurry processes include those described in U.S. Pat. No. 4,613,484. In still other embodiments, the polymerization process may be a multistage polymerization process in which one reactor is operated in a slurry phase fed to a reactor operated in a gas phase, as described in U.S. Pat. No. 5,684,097.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

One or more illustrative examples incorporating one or more inventive elements are presented herein. In the interest of clarity, not all features of a physical implementation are described or shown in the present disclosure. It will be appreciated that in the development of a physical embodiment incorporating one or more elements of the application, numerous implementation-specific decisions must be made to achieve the developers' goals, such as compliance with system-related, business-related, government-related and other constraints, which will vary from one implementation to another. While a developer's efforts may be time-consuming, such efforts would still be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

Although the compositions and methods are described herein in terms of "comprising" various components or steps, the compositions and methods can also "consist essentially of, or" consist of, the various components and steps.

Additional embodiments

The present disclosure further relates to the following non-limiting embodiments.

Embodiment 1. Method comprising:

providing a catalyst slurry comprising a supported catalyst, the supported catalyst comprising a support material, at least one catalyst compound, and at least one activator;

Introducing the catalyst slurry into a first line in fluid communication with a mechanically agitated mixing tank;

introducing at least a first portion of a catalyst solution comprising a first catalyst compound already contained on the supported catalyst or a second catalyst compound different from the first catalyst compound and not contained on the supported catalyst into a second line in fluid communication with the mechanically agitated mixing tank;

contacting the catalyst slurry with the catalyst solution in the mechanically agitated mixing tank to obtain a modified catalyst slurry from the mechanically agitated mixing tank, the modified catalyst slurry comprising a modified supported catalyst that incorporates at least a portion of the first catalyst compound or the second catalyst from the catalyst solution;

feeding the modified catalyst slurry to a fluidized bed gas phase reactor, and

Polymerizing an alpha-olefin under polymerization conditions in the fluidized bed gas phase reactor to obtain a polyolefin.

Embodiment 2. The method of embodiment 1, wherein the catalyst solution and the catalyst slurry have a contact time within the mechanically agitated mixing tank of from about 30 minutes to about 40 minutes.

Embodiment 3. The method of embodiment 1 or embodiment 2, further comprising:

A second portion of the catalyst solution is introduced into the first line upstream of the mechanically agitated mixing tank.

Embodiment 4. The method of embodiment 3, wherein the catalyst solution and the catalyst slurry have a contact time in the first line of at least about 5 minutes.

Embodiment 5. The method of any of embodiments 1-4, wherein the mechanically agitated mixing tank has a volume of from about 10L to about 30L.

Embodiment 6. The method of any of embodiments 1-5, wherein the catalyst solution comprises the second catalyst compound.

Embodiment 7 the method of any of embodiments 1-6 wherein the first catalyst compound comprises a first metallocene and the second catalyst compound comprises a second metallocene different from the first metallocene.

Embodiment 8 the process of any of embodiments 1-7 wherein the at least one catalyst compound on the supported catalyst comprises at least the first catalyst compound and the catalyst solution comprises the second catalyst compound.

Embodiment 9. The method of embodiment 8, wherein the at least one catalyst compound on the supported catalyst further comprises the second catalyst compound.

Embodiment 10. The method of any of embodiments 1-9 wherein the first catalyst compound comprises racemic/meso-dimethyl-dimethylsilylbis [ ((trimethylsilyl) methyl) cyclopentadienyl ] hafnium.

Embodiment 11. The method of any of embodiments 1-10 wherein the second catalyst compound comprises racemic/meso-dimethyl-bis (1-methylindenyl) zirconium.

Embodiment 12. The method of any of embodiments 1-11, wherein the at least one activator comprises an aluminoxane.

Embodiment 13 the method of any of embodiments 1-12, wherein the modified catalyst slurry is fed into the fluidized bed gas phase reactor at a flow rate of from about 0.1 kg/hr-cm ³ to about 0.5 kg/hr-cm ³ based on the volume of the fluidized bed gas phase reactor.

Embodiment 14. The method of any of embodiments 1-13, wherein the alpha-olefin comprises ethylene and optionally, one or more alpha-olefin comonomers.

Embodiment 15. The method of any of embodiments 1-14, wherein the catalyst slurry further comprises mineral oil, wax, induced condensing agent, or any combination thereof.

Embodiment 16. The method of embodiment 15, wherein the mineral oil is present at a concentration of about 8 wt.% to about 68 wt.%, the wax is present at a concentration of about 2 wt.% to about 15 wt.%, and the induced condensing agent is present at a concentration of about 30 wt.% to about 90 wt.%, based on the total mass of the mineral oil, the wax, and the induced condensing agent in the catalyst slurry.

Embodiment 17 the method of embodiment 15 or embodiment 16, wherein the induced condensing agent is present and the induced condensing agent comprises propane, isobutane, isopentane, isohexane, or any combination thereof.

Embodiment 18. The method of any of embodiments 1-17, wherein the catalyst slurry comprises from about 1 wt.% to about 40 wt.% solids, based on the total mass of the catalyst slurry.

Embodiment 19 the method of any of embodiments 1-18, wherein the polymer sheet is formed at a rate (ratio) of about 0.3% or less based on the total polyolefin production rate (atotal polyolefin production rate).

To facilitate a better understanding of the various embodiments of the present disclosure, the following examples of preferred or representative embodiments are presented. The following examples should not be construed as limiting in any way, or limiting the full scope of the invention.

Examples

The 1-hexene/ethylene copolymerization reaction is conducted using a conventional multi-catalyst reaction system in which the catalyst slurry and catalyst solution are statically mixed to produce a modified catalyst slurry (e.g., a system similar to system 100 in fig. 1, except that a mechanically agitated mixing tank is replaced with a static mixer), and using a modified system (e.g., a system similar to system 200 in fig. 2) that utilizes a jumper line to produce a modified catalyst slurry, with further in-line mixing upstream of the static mixer. The supported catalyst in the catalyst slurry comprises racemic/meso-dimethyl-silyl-bis [ (trimethylsilyl) methyl) cyclopentadienyl ] hafnium and the catalyst solution comprises a solvent solution of racemic/meso-dimethyl-bis (1-methylindenyl) zirconium. By utilizing a jumper line, an additional 6.8 minutes of contact time between the catalyst slurry and the catalyst solution was achieved before the modified catalyst slurry entered the gas phase fluidized bed polymerization reactor. The polymerization reaction was carried out in the same reactor, first under conventional conditions without a jumper line (run 1), second under modified conditions using a jumper line (run 2), and finally (third) after an extended run time the reactor was returned to conventional conditions to flush the modified catalyst slurry from the reactor (run 3). Further polymerization details and characterization of the ethylene polymers produced by the polymerization reaction are given in table 1.

TABLE 1

In Table 1, the polymer melt flow ratio is the ratio of the high load polymer melt index (I ₂₁, ASTM D-1238,21.6kg,190 ℃) to the polymer melt index (I ₂, ASTM D-1238,2.16kg,190 ℃).

Comparing run 1 with run 2, the polyethylene copolymer produced by increasing the contact time between the catalyst slurry and the catalyst solution has a higher melt flow ratio. Furthermore, in test 2, the fluidized bed had a higher bed density and bed weight. Upon return to normal conditions in run 3, the performance was reduced, but did not fully reach the performance level in run 1, most likely due to the residual modified supported catalyst from run 2 remaining in the reactor.

The foregoing improvement in the increase in contact time between the catalyst slurry and the catalyst solution is further illustrated in fig. 4. FIG. 4 is a graphical representation of H ₂/ethylene flow ratio and degree of polymer sheeting under conventional catalyst slurry/catalyst solution contact conditions and extended catalyst slurry/catalyst solution contact conditions in accordance with the disclosure herein. The baseline conditions were initially established in fig. 4, wherein the contact between the catalyst solution and the catalyst slurry was performed in an in-line mixer. Subsequently, at least a portion of the catalyst solution is transferred and mixed in-line with the catalyst slurry for 5-6 minutes. The conditions are then returned to baseline conditions.

As shown in table 1 and fig. 4, the polyethylene copolymer produced by increasing the contact time between the catalyst slurry and the catalyst solution (test 2 vs. test 1) has a higher H ₂/ethylene flow ratio at a similar H ₂/ethylene gas ratio, as well as a higher polymer melt flow ratio. Under the test conditions, the increase in the H ₂/ethylene flow ratio and the increase in the melt flow ratio at a stable H ₂/ethylene gas ratio were consistent with the more catalyst in the catalyst solution catalyst becoming activated on the catalyst support with increasing contact time. Once the prolonged contact time is restored to normal conditions, the H ₂/ethylene flow ratio is reduced.

As also shown in fig. 4, the increased contact time between the catalyst solution and the catalyst slurry resulted in a decrease in sheeting rate, as indicated by the longer time between removal of the sheet polymer from the scrap bin. Each time the waste bin is emptied, the fill level is recorded in order to estimate the number of hours required for the waste bin to become completely full before emptying. The chamber emptied during run 2 and the first chamber emptied after run 2 (fig. 4) showed that the increased contact time produced a significant improvement from about 13 hours to 60 hours between chamber discharges. The increase in bed density and bed weight is also consistent with the expected reduction in sheeting. Upon returning to normal conditions, sheeting performance declines.

The present invention is therefore well adapted to attain the ends and advantages mentioned, as well as those that are inherent therein. The particular examples and configurations disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the invention. The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein and/or any optional element which is disclosed herein. While compositions and methods are described in terms of "comprising," "containing," or "including" various components or steps, the compositions and methods may also "consist essentially of or" consist of the various components and steps. All numbers and ranges disclosed above may vary by a certain amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, each range of values disclosed herein (in the form of "from about a to about b" or, equivalently, "from about a to b" or, equivalently, "from about a-b") should be understood to list each number and range encompassed within the broader range of values. In addition, the terms in the claims have their ordinary, normal meaning unless explicitly and clearly defined otherwise by the patentee. Furthermore, the indefinite articles "a" or "an" as used in the claims are defined herein to mean one or more of the element to which they are introduced.

Claims

1. Methods, including:

providing a catalyst slurry comprising a supported catalyst comprising a support material, at least one catalyst compound, and at least one activator;

introducing the catalyst slurry into a first pipeline in fluid communication with a mechanically agitated mixing tank;

introducing at least a first portion of a catalyst solution into a second line in fluid communication with the mechanically agitated mix tank, the catalyst solution comprising a first catalyst compound already contained on the supported catalyst or a second catalyst compound different from the first catalyst compound and not contained on the supported catalyst;

contacting the catalyst slurry with the catalyst solution in the mechanically agitated mix tank to obtain a modified catalyst slurry from the mechanically agitated mix tank, the modified catalyst slurry comprising a modified supported catalyst incorporating at least a portion of the first catalyst compound or the second catalyst from the catalyst solution;

feeding the modified catalyst slurry to a fluidized bed gas phase reactor; and

α-olefins are polymerized in the fluidized bed gas phase reactor under polymerization conditions to obtain polyolefins.

2. The process of claim 1 wherein said catalyst solution and said catalyst slurry have a contact time within said mechanically agitated mix tank of from about 30 minutes to about 40 minutes.

3. The method of claim 1 or claim 2, further comprising:

A second portion of the catalyst solution is introduced into the first line upstream of the mechanically agitated mix tank.

4. The process of claim 3, wherein the catalyst solution and the catalyst slurry have a contact time in the first line of at least about 5 minutes.

5. The method of claim 1 or any one of claims 2-4, wherein the mechanically agitated mix tank has a volume of about 10 L to about 30 L.

6. The method of claim 1 or any one of claims 2-5, wherein the catalyst solution comprises the second catalyst compound.

7. The process of claim 1 or any one of claims 2-6, wherein the first catalyst compound comprises a first metallocene, and the second catalyst compound comprises a second metallocene different from the first metallocene.

8. The process of claim 1 or any one of claims 2-7, wherein the at least one catalyst compound on the supported catalyst comprises at least the first catalyst compound, and the catalyst solution comprises the second catalyst compound.

9. The process of claim 8, wherein the at least one catalyst compound on the supported catalyst further comprises the second catalyst compound.

10. The process of claim 1 or any one of claims 2-9, wherein the first catalyst compound comprises rac/meso dimethyldimethylsilylbis[((trimethylsilyl)methyl)cyclopentadienyl]hafnium.

11. The process of claim 1 or any one of claims 2-10, wherein the second catalyst compound comprises rac/meso dimethyl bis(1-methylindenyl)zirconium.

12. The method of claim 1 or any one of claims 2-11, wherein the at least one activator comprises an alumoxane.

13. The process of claim 1 or any one of claims 2 to 12, wherein the modified catalyst slurry is fed into the fluidized bed gas phase reactor at a flow rate of about 0.1 kg/hr·cm ³ to about 0.5 kg/hr·cm ³ based on the volume of the fluidized bed gas phase reactor.

14. The process of claim 1 or any one of claims 2 to 13, wherein the α-olefin comprises ethylene, and optionally, one or more α-olefin comonomers.

15. The process of claim 1 or any one of claims 2-14, wherein the catalyst slurry further comprises mineral oil, wax, an induced condensing agent, or any combination thereof.

16. The process of claim 15, wherein the mineral oil is present at a concentration of about 8 weight percent to about 68 weight percent, the wax is present at a concentration of about 2 weight percent to about 15 weight percent, and the induced condensing agent is present at a concentration of about 30 weight percent to about 90 weight percent, based on the total mass of the mineral oil, wax, and induced condensing agent in the catalyst slurry.

17. The method of claim 15 or claim 16, wherein the induced condensing agent is present, and the induced condensing agent comprises propane, isobutane, isopentane, isohexane, or any combination thereof.

18. The process of claim 1 or any one of claims 2-17, wherein the catalyst slurry comprises from about 1 wt% to about 40 wt% solids, based on the total mass of the catalyst slurry.

19. The method of claim 1 or any one of claims 2 to 18, wherein polymer sheets are formed at a rate of about 0.3% or less based on the total polyolefin production rate.