Catalyst supply system

Abstract

The present invention relates to a method for supplying a polymerization catalyst to a polymerization reactor, the method comprising the following steps: (i) forming a catalyst slurry containing an oil and a solid catalyst component in a first catalyst preparation vessel; (ii) transferring the catalyst slurry from the first catalyst preparation vessel to a first catalyst supply vessel; (iii) maintaining the catalyst slurry in the first catalyst supply vessel in a homogeneous state; and (iv) removing a portion of the catalyst slurry from the first catalyst supply vessel, preferably continuously removing the catalyst slurry from the first catalyst supply vessel, and introducing the removed portion of the catalyst slurry into a polymerization reactor; wherein the oil has a viscosity of 25 to 1500 mPa under conditions in the first catalyst preparation vessel and the first catalyst supply vessel. * s, and the catalyst slurry is transported downwardly along a substantially vertical path from a first catalyst supply vessel to a reactor.

Description

Technical Field

[0001] The present application relates to a method for supplying a polymerization catalyst to a polymerization reactor, a method for producing an olefin polymer in a polymerization reactor, an olefin polymer obtained by this method, and a catalyst slurry supply system for producing an olefin polymer in a polymerization reactor.

Background Art

[0002] <Background of the Invention> Prior art systems for supplying a polymerization catalyst often include two containers arranged in parallel and close to each other for supplying the catalyst to a polymerization reactor. The catalyst can be prepared and supplied from each tank, but in practice, at a given time, often one container is used for the preparation of the catalyst oil slurry and the other container is used for supply. EP 3241611 discloses a method for supplying a polymerization catalyst to a polymerization reactor, comprising the following steps: (i) holding a catalyst slurry containing a diluent and a solid catalyst component in a catalyst supply container; (ii) continuously withdrawing a stream of the catalyst slurry from the catalyst supply container; and (iii) introducing a portion of the withdrawn catalyst slurry into the polymerization reactor. The diluent has a dynamic viscosity of 0.01 to 20 mPa * s under the conditions in the catalyst supply container.

[0003] EP 1671697 A1 discloses a polymerization method comprising the following steps: (i) forming a catalyst slurry in a catalyst supply container containing an oil and a solid polymerization catalyst component; (ii) maintaining the slurry in the catalyst supply container in a homogeneous state; (iii) continuously withdrawing a portion of the catalyst slurry from the catalyst supply container and introducing the withdrawn slurry into the polymerization reactor.

[0004] WO 2010 / 086392 A1 discloses a method for transitioning between two different catalysts in the production of polypropylene homopolymers or copolymers during continuous olefin polymerization, more specifically in a continuous slurry / gas phase polymerization reaction involving a preliminary prepolymerization reaction. The method includes a) interrupting the supply of a first catalyst to a prepolymerization reactor, then b) introducing a second catalyst into the prepolymerization reactor, and c) adapting the reaction conditions in the prepolymerization reactor, slurry reactor, and subsequent gas phase reactor. The transition is carried out between a Ziegler-Natta catalyst and a self-supported solid metallocene catalyst prepared by using an emulsion / solidification technique, or vice versa, and is carried out in the absence of additives that deactivate or kill the catalyst.

[0005] The layout of known supply systems often has the drawback that the containers are located quite far from the injection points of the (pre)polymerization reactors. As a result, in known systems according to the prior art, the catalyst supply lines sometimes become clogged due to the length and / or complexity of the piping. Also, during the switch from one tank to the other, there are problems with pump clogging.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, in a method for supplying a polymerization catalyst to a polymerization reactor, it is desirable to avoid the aforementioned drawbacks, especially clogging.

Means for Solving the Problems

[0008] <Summary of the Invention> This problem is solved by a method for supplying a polymerization catalyst to a polymerization reactor, said method comprising the following steps: (i) forming a catalyst slurry comprising an oil and a solid catalyst component in a first catalyst preparation vessel; (ii) transferring the catalyst slurry from the first catalyst preparation vessel to a first catalyst supply vessel; (iii) maintaining the catalyst slurry in the first catalyst supply vessel in a homogeneous state; (iv) withdrawing a portion of the catalyst slurry from the first catalyst supply vessel, preferably continuously withdrawing the catalyst slurry from the first catalyst supply vessel, and introducing a portion of the withdrawn catalyst slurry into a polymerization reactor; comprising said oil having a dynamic viscosity of 25 to 1500 mPa * s under the conditions in the first catalyst preparation vessel and the first catalyst supply vessel, said catalyst slurry being transferred downward along a path substantially perpendicular from the first catalyst supply vessel to the reactor.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Catalyst preparation and catalyst supply are carried out in different containers. As a result, the supply container can be placed fairly close to the polymerization reactor. The catalyst supply container is arranged above the polymerization reactor, and the polymerization reactor can also be a prepolymerization reactor. In particular, the position above the polymerization reactor refers to the position above the injection point of each reactor. It should be understood that the upper position of the catalyst supply container also covers the position arranged obliquely above each reactor. It is important that gravity supports the transfer from the supply container to the injection point. Thus, clogging can be avoided and the complexity of the supply pipe can be reduced. Also, the burden on the pump is reduced.

[0011] In addition, the system according to the present invention enables the preparation of a catalyst-oil slurry of dry catalyst powder in a polyolefin plant because the catalyst preparation container can be arranged anywhere in the plant, where the catalyst powder can be easily supplied. For example, the preparation container may be installed in a location close to the ground for this simplification of component supply. Thereby, the transfer cost of the catalyst is reduced and the time for supplying the catalyst powder to the system is shortened. On the other hand, the preparation of the catalyst-oil slurry has the advantage that the supply of the catalyst in oil is very accurate and reliable by a positive displacement pump. Furthermore, the oil protects the catalyst from catalyst poisons and makes the handling of waste catalysts, especially those containing exothermic catalysts, safer.

[0012] The container layout and piping layout according to the present invention prevent clogging. Furthermore, according to the present invention, the plant can supply the catalyst at a higher slurry concentration, thereby reducing the amount of oil supplied to the process.

[0013] The solid catalyst component applied in the method of the present invention is suspended in oil to produce a catalyst slurry.

[0014] The oil is selected from the group consisting of food-approved white oils and mixtures thereof; and / or the catalyst supplied to the first catalyst preparation container is dry catalyst powder; and / or the catalyst concentration in the slurry is 10 to 40% by weight, preferably 15 to 30% by weight, more preferably 20 to 25% by weight based on the total amount of the slurry.

[0015] The oil used must be inert to the catalyst. That is, it must not contain groups containing atoms selected from components that easily react with the catalyst, such as oxygen, sulfur, nitrogen, chlorine, fluorine, bromine, iodine, etc. Also, groups containing double bonds or triple bonds should be avoided. In particular, the presence of compounds such as water, alcohol, organic sulfides, ketones, carbon monoxide, carbon dioxide, and acetylene compounds should be avoided.

[0016] The oil is preferably white oil, more preferably food-approved white oil or a mixture of food-approved white oils. The white oil may be white mineral oil. White mineral oil is a special mineral oil obtained by highly purifying to remove impurities such as aromatic hydrocarbons, sulfur, and nitrogen. Generally, it consists of alkanes and naphthenes, has a molecular weight of 250 - 400 g / mol, and belongs to the lubricating oil fraction. It is colorless, odorless, chemically inert, and has excellent light and heat stability.

[0017] White mineral oil (i.e., white mineral oil, white oil) is often used as a diluent for the catalyst, especially as a diluent for polyolefin polymerization catalysts.

[0018] Food-approved white oil may be white oil for food. White oil for food is a special mineral oil product obtained by further purifying and removing aromatic hydrocarbons from ordinary white oil products. It has excellent light and heat stability, yellowing resistance, oxidation resistance, and viscosity-temperature performance, is suitable for the human body, and is safe and non-toxic. Examples of suitable food-approved white oils include Clarion® Food Grade White Mineral Oil 70, Phillips 66® White Oil, and FOODGUARD USP White Oil 15.

[0019] The viscosity of the oil must be such that a stable slurry is obtained and the tendency of the catalyst particles to settle is minimized. Thus, the oil should not have too low a viscosity. On the other hand, the slurry must be easily transferable into the polymerization reactor. A very high viscosity is problematic for handling the catalyst because highly viscous fluids require special handling operations. Furthermore, the viscous wax remaining in the polymer product after polymerization can have an adverse effect on the properties of the product.

[0020] The kinematic viscosity of the oil in the catalyst slurry is preferably 65 - 75 mm 2 / s. The kinematic viscosity of the oil is measured in accordance with ISO 3104.

[0021] Under the conditions in the catalyst preparation vessel and the catalyst supply vessel, it has been found that the best results are obtained when the dynamic viscosity of the oil is 25 - 1500 mPa * s. Preferably, when measured at the operating temperature of the supply vessel, the dynamic viscosity is 30 - 1500 mPa * s, more preferably 35 - 990 mPa * s. The dynamic viscosity is the product of the kinematic viscosity and the density.

[0022] In particular, the viscosity of the oil needs to be high enough to enable the operation of the supply pump. Furthermore, the oil needs to lubricate the piston of the catalyst supply pump and enable its smooth operation.

[0023] Surprisingly, when the viscosity is selected within the above range, the components of the catalyst slurry can be easily handled in various handling operations, the catalyst particles have a minimum tendency to settle during residence in the supply vessel and piping, and smooth operation of the supply pump is ensured.

[0024] The solid catalyst component may be supplied as a dry powder or in an oil slurry.

[0025] Preferably, the catalyst supplied to the catalyst preparation vessel is dry catalyst powder.

[0026] When the catalyst is supplied as a slurry, the oil used in the slurry is preferably the same as or at least similar to the oil used in the catalyst supply. The concentration of the solid catalyst component in the transfer slurry may be up to 450 kg / m 3 .

[0027] The concentration of the solid catalyst component can be freely selected so that the desired catalyst supply rate can be conveniently obtained. However, since it may be difficult to maintain a stable slurry, the concentration should not be too high. On the other hand, if the concentration is too low, an excessive amount of oil will be used, which may cause a problem that the level of extractables in the final polymer product increases.

[0028] The solid catalyst component may contain a polymer. Thus, it may be prepolymerized to produce a small amount of polymer in the solid catalyst component, for example, 0.01 to 50 grams of polymer per gram of the solid component. The monomer used for prepolymerization may be the same as or different from that used in the polymerization reactor.

[0029] In the method of the present invention, the catalyst is selected from the group consisting of Ziegler-Natta catalysts, metallocene catalysts, late transition metal catalysts, and mixtures thereof. Any solid catalyst component may be used in the method of the present invention.

[0030] The catalyst may be of the Ziegler-Natta type. For example, as disclosed in EP 688794, WO 91 / 16361, WO 93 / 13141, WO 94 / 14857, WO 99 / 51646, and WO 01 / 55230, it may contain a magnesium compound and a titanium compound supported on an inorganic oxide carrier. However, as disclosed in WO 03 / 000756, WO 03 / 000757, WO 03 / 000754, WO 92 / 19653, WO 93 / 07182, WO 97 / 36939, and WO 99 / 58584, it may also contain a titanium compound supported on magnesium halide. The catalyst may also be an unsupported one containing particles of solid titanium trichloride, optionally containing additional components such as aluminum trichloride.

[0031] The catalyst may also typically be a chromium catalyst supported on silica. Such catalysts are disclosed in particular in WO 99 / 52951 and WO 97 / 27225.

[0032] Furthermore, the catalyst may be a metallocene catalyst. In many cases, such catalysts are preferably supported on an inorganic oxide carrier, as disclosed in WO 95 / 12622, WO 96 / 32423, WO 98 / 32776, and WO 00 / 22011. However, the catalyst may also be prepared by forming a carrier from an aluminoxane and incorporating a metallocene compound onto the aluminoxane. A method for preparing such a solid metallocene catalyst component is disclosed in WO 03 / 051934.

[0033] The catalyst slurry may be formed by any method known in the art. According to a preferred method, the solid catalyst component is introduced into oil under stirring.

[0034] The slurry is prepared in a first catalyst preparation vessel.

[0035] Preferably, a homogeneous slurry is prepared in the first catalyst preparation vessel. The homogeneous slurry is maintained by agitation. The agitation can be obtained by circulating the slurry using a circulation pump and a pipe connecting the pump and the first catalyst preparation vessel. Alternatively, the first catalyst supply vessel is provided with an agitator that continuously moves the slurry in the supply vessel. Preferably, the first catalyst supply vessel is provided with an agitator. The elements of the agitator should be selected such that uniform agitation is obtained throughout the total volume of the first catalyst supply vessel and there are no dead spots where the catalyst can settle. Such agitator elements, such as anchor-type elements, axial and radial impellers, are well known in the art and those skilled in the art can select a suitable combination for each shape of the first catalyst supply vessel. The first catalyst supply vessel may also be provided with baffles known in the art to further improve agitation.

[0036] As known to those skilled in the art, the rotational speed N of the agitator should be selected such that N≧N js where N js is exactly the speed at which suspension occurs and can be calculated from correlations available in the art, for example, Zwietering Th.N., “Suspending of solids particles in liquid by agitators”, Chem Eng Sci, Vol 8, pp 244 - 254, 1958. Preferably, the rotational speed N of the agitator is 50 - 75 rpm.

[0037] The pressure in the preparation vessel is not critical. It can be selected within the operating range of the process equipment. In particular, it should be selected such that the pump can operate without problems. To minimize the final leakage of air and / or moisture into the preparation vessel, it is desirable that the pressure in the preparation vessel is higher than atmospheric pressure.

[0038] The preparation vessel must be maintained in an inert atmosphere. In particular, the presence of oxygen and moisture should be avoided. Therefore, all connections to the preparation vessel, such as piping joints and agitator shaft bearings, need to be carefully designed to exclude leakage from the atmosphere.

[0039] The gas phase in the preparation vessel preferably consists of nitrogen, argon or a similar inert gas, or a mixture thereof. Also, the preparation vessel should be capable of being cleaned with an inert gas, preferably nitrogen.

[0040] Also, process chemicals such as lubricating oil for bearings need to be selected so as not to contain components harmful to the catalyst, or carry-over into the preparation vessel needs to be prevented.

[0041] In step (ii), the catalyst slurry is transferred from the first catalyst preparation vessel to the first catalyst supply vessel via a catalyst transfer line.

[0042] Preferably, the catalyst slurry is transferred from the first catalyst preparation vessel to the first catalyst supply vessel by applying gas pressure or using a pump.

[0043] More preferably, there is a second catalyst preparation vessel. In both preparation vessels, the catalyst slurry can be formed independently.

[0044] The characteristics of the above-mentioned first catalyst preparation vessel also apply to the second catalyst preparation vessel.

[0045] More preferably, the catalyst slurry is transferred from the first catalyst preparation vessel and the second catalyst preparation vessel to the first catalyst supply vessel via a first catalyst transfer line. There may also be a second catalyst supply vessel to which the slurry can be transferred.

[0046] The temperature of the slurry in the catalyst supply vessel is not critical. However, it should be avoided that the temperature is too low or too high. Otherwise, the viscosity of the slurry may be too high, making handling in the process inconvenient, or the viscosity of the slurry may be too low, making the particles prone to sedimentation. The temperature may be selected within the range of -30°C to +80°C, preferably 0°C to 60°C.

[0047] It is preferable to provide a heating / cooling jacket on the catalyst supply vessel so that the temperature inside the vessel can be maintained at a desired level. In particular, the temperature of the slurry should be adjusted so that the viscosity of the oil is within the desired range. Furthermore, temperature fluctuations should be avoided because they can cause fluctuations in the density of the slurry. If the density of the slurry changes, the supply rate of the catalyst will also change accordingly, which may cause fluctuations in the polymerization process.

[0048] The supply rate is controlled based on the catalyst rate and the production rate. The supply rate should be as stable as possible.

[0049] The pressure inside the catalyst supply vessel is not important. It can be selected within the operating range of the process equipment. In particular, it should be selected so that the pump can operate without problems. To minimize the final leakage of air and / or moisture into the catalyst supply vessel, it is desirable that the pressure inside the catalyst supply vessel be higher than atmospheric pressure.

[0050] The catalyst supply vessel must be maintained in an inert atmosphere. In particular, the presence of oxygen and moisture should be avoided. Therefore, all connections to the supply vessel, such as piping joints and agitator shaft bearings, need to be carefully designed to eliminate leakage from the atmosphere.

[0051] Also, process chemicals such as lubricating oil for the bearings need to be selected so as not to contain components harmful to the catalyst, or carryover to the preparation vessel needs to be prevented. It is particularly preferable to use the same oil as the oil used as a diluent for the catalyst slurry as the lubricating oil.

[0052] The gas phase inside the catalyst supply vessel preferably consists of nitrogen, argon, and similar inert gases, or a mixed gas thereof. Also, the catalyst supply vessel should be equipped with the possibility of purging the vessel with an inert gas, preferably nitrogen.

[0053] Optionally, the catalyst slurry is contacted with an activator and / or an electron donor in a preparation vessel, or before being introduced into the polymerization reactor, or before being introduced into a line upstream of the polymerization reactor.

[0054] The catalyst slurry may contain additional components such as an activator, an electron donor, a modifier, an antistatic agent, etc. When using such components, the component may be integrated into the catalyst slurry in the catalyst supply vessel, or integrated into the catalyst slurry stream introduced into the polymerization reactor, or introduced directly into the polymerization reactor without prior contact with the catalyst slurry.

[0055] Useful activators include organometallic compounds such as organoaluminum compounds, especially aluminum alkyls. Examples of such preferred compounds are trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, and isoprenylaluminum. Other useful compounds are methylalumoxane, triisobutylalumoxane, hexaisobutylalumoxane, and other alumoxanes, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum sesquichloride, ethylaluminum sesquichloride, diethylzinc, and triethylboron.

[0056] Examples of electron donors may include ethers, esters, ketones, alcohols, carboxylic acids, silicon ethers, imides, amides, and amines.

[0057] Furthermore, it is also possible to add a small amount of a drag reducer into the catalyst slurry. Such a drag reducer is typically a C6 - C 15 alpha-olefin, preferably a C8 - C 13They are soluble polymers of higher alpha-olefins such as alpha-olefins and their mixtures. These may also contain a small amount of comonomer units derived from other olefins. However, it is important that the drag reducer is soluble in the oil. The drag reducer is used in an amount of 0.1 to 1000 ppm, preferably 0.5 to 100 ppm, more preferably 1 to 50 ppm based on the weight of the catalyst slurry. It has already been found that the tendency of the slurry to settle is reduced even in this small amount. Although an excessive amount of the drag reducer has no drawbacks from the method perspective, it should be noted that the drag reducer remains in the polymer product and may have an adverse effect on some product characteristics when used in a large amount.

[0058] Drag reducers are commercially available, especially supplied by M-I Production Chemicals and Conocon. The former supplies a product with the trade name NECADD 447 (registered trademark), which has been found to be useful for preventing the sedimentation of catalyst particles. The drag reducer usually has a weight average molecular weight of at least 250,000 g / mol, preferably at least 500,000 g / mol, more preferably at least 800,000 g / mol. In particular, the drag reducer has a weight average molecular weight of more than 1,000,000 g / mol.

[0059] According to a preferred embodiment, in the method of the present invention, a second catalyst preparation container, a first catalyst supply container, and a second catalyst supply container are applied. The catalyst slurry in the first catalyst preparation container is transferred to the first catalyst supply container via the first catalyst transfer line, and the catalyst slurry in the second catalyst preparation container is transferred to the second catalyst supply container via the second catalyst transfer line.

[0060] The characteristics of the above-mentioned first catalyst preparation container also apply to the second catalyst preparation container.

[0061] A method having two catalyst preparation vessels and two catalyst supply vessels with separate transfer lines can improve operational flexibility, which leads to an improvement in the method's capabilities. Furthermore, the method may include two catalyst preparation vessels and two catalyst supply vessels that are non-separated and preferably have cross-transfer lines.

[0062] The cross-transfer line includes a switching system. The first supply line and the second supply line may cross each other and may also include a switching system. The switching system can be switched during the use of the first or second transfer line for transferring the catalyst slurry from the first or second catalyst preparation vessel to the first or second catalyst supply vessel, and during the use of the first or second supply line for transferring a portion of the withdrawn catalyst slurry from the first or second catalyst supply vessel to the polymerization reactor. Preferably, the switching system includes two or more valves.

[0063] The catalyst slurry is maintained in a homogeneous state (step (iii)).

[0064] A portion of the slurry can be continuously withdrawn from the catalyst supply vessel and introduced into the polymerization reactor.

[0065] In step (iv), the catalyst slurry is transferred from the first catalyst supply vessel and / or the second catalyst vessel to the polymerization reactor using at least one valveless piston pump. The valveless piston pump is arranged at a level lower than the level of the catalyst supply vessel.

[0066] Valveless piston pumps are optimal for applications involving high viscosities and particulate or colloidal fluids. Valveless piston pumps operate extremely accurately.

[0067] In the method of the present invention, the transfer from the first catalyst preparation vessel to the first catalyst supply vessel and / or the transfer from the second catalyst preparation vessel to the second catalyst supply vessel can be carried out batchwise, preferably batchwise. Therefore, the flow rate in the pipe can be made high enough so that sedimentation does not occur.

[0068] In the method of the present invention, at least one transfer line can be emptied using oil and / or N2. The transfer line from the catalyst preparation container to the catalyst supply container is pneumatically actuated at N2-pressure.

[0069] Preferably, the catalyst slurry taken out from the catalyst supply container and introduced into the polymerization reactor is transferred from the catalyst supply container to the polymerization reactor via at least one supply line.

[0070] Preferably, at least one supply line has a length of 2 to 12 m, and preferably all supply lines have a length of 2 to 12 m. Even more preferably, at least one supply line has a length of 5 to 12 m, more preferably 10 to 12 m.

[0071] Optionally, the method of the present invention includes the step of monitoring the level of the catalyst slurry by level sensors in the catalyst supply container, preferably the first catalyst supply container and the second catalyst supply container. Further, the level measurement may be configured in the catalyst preparation container, and / or the step of monitoring the level of the catalyst slurry by level sensors in the catalyst preparation container, preferably the first catalyst preparation container and the second catalyst preparation container, may be configured.

[0072] The level sensor equipped in the catalyst supply container can estimate the level of the catalyst slurry. For example, a radioactive level gauge can be used. These gauges can be used for both level measurement of the concentrated (or sedimented) slurry and homogeneous slurry in the supply container. By using the level sensor, the operator can prepare a new batch of catalyst slurry in the preparation container. When the catalyst slurry (or concentrated catalyst slurry) in the first catalyst supply container runs out, the operator can stop the withdrawal of the catalyst slurry from the first catalyst supply container and start from the second catalyst supply container, or alternatively transfer a new batch of catalyst slurry from the preparation container to the catalyst supply container.

[0073] It is also possible to transfer a small amount of slurry continuously or intermittently from the preparation container to the catalyst supply container. When using such a procedure, it is possible to keep the level of the catalyst slurry or the concentrated catalyst slurry in the catalyst supply container substantially constant.

[0074] Sensors that can be installed in this system are, for example, gas sensors, pressure sensors, temperature sensors, and electrostatic sensors, etc.

[0075] The present invention provides an additional step of stopping the withdrawal of the catalyst slurry from one of the first catalyst supply container or the second catalyst supply container and starting the withdrawal of the catalyst slurry from the other of the first catalyst supply container or the second catalyst supply container in response to a signal from the level sensor.

[0076] In a further aspect, the present invention relates to a method for producing an olefin polymer in a polymerization reactor, which includes the step of supplying a polymerization catalyst to the polymerization reactor using the method as described above.

[0077] Preferably, the method for producing an olefin polymer in a polymerization reactor includes the step of supplying a polymerization catalyst to the polymerization reactor by using the above method. The method comprises the following: (i) A step of continuously introducing at least one olefin monomer into the polymerization reactor (ii) Optionally, a step of continuously introducing a diluent and / or hydrogen into the polymerization reactor (iii) Operating the polymerization reactor under conditions such that at least one olefin monomer is polymerized by the polymerization catalyst to form a reaction mixture containing the catalyst, unreacted monomer, formed polymer, and optionally a diluent and / or hydrogen; and (iv) Optionally, a step of removing a part of the reaction mixture from the polymerization reactor are included.

[0078] In some cases, it is preferable that a prepolymerization stage precedes the polymerization stage. In prepolymerization, a small amount of olefin, preferably 0.1 to 500 g of olefin per 1 g of catalyst, is polymerized. Usually, prepolymerization is carried out at a lower temperature and / or a lower monomer concentration than the actual polymerization. Typically, prepolymerization is carried out at 0 to 70 °C, preferably 10 to 60 °C. Usually, the monomer used in prepolymerization is the same as the monomer used in the subsequent polymerization stage. It is also possible to supply a plurality of monomers to the prepolymerization stage. Descriptions regarding prepolymerization can be found, for example, in WO 96 / 18662, WO 03 / 037941, GB 1532332, EP 517183, EP 560312, and EP 99774.

[0079] In this polymerization method, an alpha-olefin having 2 to 20 carbon atoms can be polymerized. In particular, ethylene and / or propylene are optionally polymerized together with higher alpha-olefins. As comonomers, 1-butene and 1-hexene are preferred.

[0080] The diluent can be any liquid that is inert to the catalyst. Suitable diluents are hydrocarbons having at least 3 carbon atoms. Preferably, the diluent is selected from the group consisting of C3~C 10 hydrocarbons and mixtures thereof. In particular, the diluent is selected from the group consisting of propane, n-butane, isobutane, n-pentane, isopentane, and mixtures thereof.

[0081] It is within the scope of the present invention to carry out polymerization in at least one polymerization stage. Also, as disclosed in WO 92 / 12182, EP 22376, EP 713888, and WO 98 / 58975, it is also known in the art to carry out polymerization in at least two polymerization stages in order to produce bimodal polyolefins such as bimodal polyethylene and bimodal polypropylene. Furthermore, as disclosed in WO 98 / 58976, multistage polymerization may be used to produce a heterophasic propylene copolymer. It should be understood that the present invention is not limited to a specific number of polymerization stages and any number is possible.

[0082] When the polymerization is carried out as a slurry polymerization, any suitable reactor type known in the art may be used. Continuous stirred tank reactors and loop reactors are suitable examples of useful reactor types. In particular, loop reactors are preferred because of their flexibility.

[0083] The slurry polymerization may be carried out in the normal liquid slurry state or, alternatively, such that the temperature and pressure in the reactor exceed the critical temperature and critical pressure of the fluid mixture in the reactor. Such a polymerization process is called supercritical slurry polymerization. Descriptions of liquid slurry polymerization are given inter alia in EP 249689 and US 3262922, and descriptions of supercritical slurry polymerization are given in WO 92 / 12181 and US 3294772.

[0084] In any method known in the art, including continuous withdrawal and intermittent withdrawal, the slurry may be withdrawn from the reactor. When the withdrawal is intermittent, it may be achieved by using so-called setting legs that allow the slurry to settle before discharging the settled slurry from the reactor. Settling legs are generally known in the art and are disclosed, for example, in US 4613484 and US 4121029.

[0085] When the slurry is continuously withdrawn from the reactor, it may be withdrawn without a concentration step or may be concentrated before or after withdrawal. For economic reasons, it is preferred to concentrate the slurry. Suitable concentration methods are, in particular, hydrocyclones or sieves. Usually, in such a method, the slurry is continuously withdrawn from the reactor and passed through a concentration device such as a hydrocyclone or a sieve. The bottom flow is directed to the product withdrawn and the overflow is recycled to the polymerization reactor. Such a method is disclosed in EP 1415999.

[0086] In a further aspect, the present invention provides an olefin polymer obtainable by a method for producing an olefin polymer in a polymerization reactor, the method comprising the step of feeding a polymerization catalyst into the polymerization reactor using the method of the present invention as described above.

[0087] The olefin polymer can be obtained by the above method. Polymers obtained from this method include all olefin polymers and copolymers known in the art, such as high-density polyethylene (HDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer, random copolymer of propylene and ethylene, or random copolymer of propylene and higher alpha-olefins, heterophasic copolymer of propylene and ethylene, poly-1-butene, and poly-4-methyl-1-pentene. When higher alpha-olefins are used as comonomers, they are preferably selected from the group consisting of 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene.

[0088] In another aspect, the present invention provides a catalyst slurry supply system for producing an olefin polymer in a polymerization reactor, comprising: - a first catalyst preparation container for forming a catalyst slurry containing an oil and a solid catalyst component, preferably at least two catalyst preparation containers; - a first catalyst supply container for maintaining the catalyst slurry in a homogeneous state, preferably at least two catalyst supply containers - a polymerization reactor - a first transfer line connecting the first catalyst preparation container to the first catalyst supply container, preferably at least two transfer lines connecting at least two catalyst preparation containers to at least two catalyst supply containers - a first supply line connecting the first catalyst supply container to the polymerization reactor, preferably at least two supply lines connecting at least two catalyst supply containers to the polymerization reactor; Here, the first supply line is equipped with a pump, preferably at least two supply lines are equipped with at least one pump, the first catalyst supply container is arranged above the polymerization reactor, and preferably at least two catalyst supply containers are arranged above the polymerization reactor.

[0089] Preferably, the catalyst slurry supply system for producing an olefin polymer in the polymerization reactor includes a second catalyst preparation container, where the first catalyst preparation container is connected to the first catalyst supply container via a first transfer line, and the second catalyst preparation container is connected to the second catalyst supply container via a second transfer line.

[0090] Preferably, the first supply line has a length of 2 to 12 m, and preferably all supply lines have a length of 2 to 12 m. Even more preferably, the first supply line and / or at least two supply lines have a length of 5 to 12 m, more preferably 10 to 12 m.

[0091] The supply line may be equipped with a catalyst flowmeter. A flowmeter suitable for measuring the catalyst supply rate is disclosed in WO 2004 / 057278 or is commercially available particularly from Oxford Instruments. Such a flowmeter may be used as part of a control loop for controlling the catalyst supply rate. For example, the signal from the flowmeter is compared with a predetermined set value, and the signal to the metering pump is adjusted based on the difference.

[0092] With the above system, the catalyst preparation function and the supply function to the method can be separated. Therefore, the catalyst preparation container may be at a certain distance from the injection point of the polymerization reactor, and the catalyst supply container can be arranged as close as possible to the injection point of the polymerization reactor. By arranging the catalyst supply container above the polymerization reactor, gravity supports the transfer of the catalyst slurry to the polymerization reactor.

[0093] Preferably, the catalyst supply container is arranged above the injection point of the polymerization reactor.

[0094] Preferably, the catalyst supply vessel is located vertically above or obliquely above the polymerization reactor, and more preferably, at least two catalyst supply vessels are located vertically above or obliquely above the polymerization reactor.

[0095] The position of the preparation vessel can be freely selected. Usually, the position of the preparation vessel is determined by the overall structure of the system. Moreover, its position is regularly selected so that the supply of the preparation vessel is simplified. However, the preparation vessel can be arranged below the level of the catalyst supply vessel. Preferably, the preparation vessel is arranged below the catalyst supply vessel.

[0096] Such a system having two catalyst preparation vessels and two catalyst supply vessels with a separation transfer line can improve the production capacity of olefin polymers.

[0097] All embodiments described with respect to the method for supplying a polymerization catalyst to a polymerization reactor are also applicable to a catalyst slurry supply system for producing an olefin polymer.

[0098] Unless explicitly stated otherwise, the description of the present invention is to be understood as being able to combine any one or more of the preferred embodiments of the present invention described above with the present invention described in its most general features. In addition, it will be understood that variations of the features and functions disclosed above, and variations of other features and functions, or alternatives thereto, may be combined in many other different systems or applications. It is contemplated that various alternatives, modifications, variations, or improvements not presently foreseen or expected may be made by those skilled in the art thereafter, and these are also intended to be encompassed by the claims.

[0099] <Description of the Figures> Figure 1 shows an example of the method of the present invention. This method includes a catalyst preparation vessel (1), a catalyst supply vessel (3), a catalyst supply pump (4), and a polymerization reactor (6). The catalyst preparation vessel (3) can be installed on the ground for easy access. A catalyst slurry is formed in the catalyst preparation vessel (1), and the catalyst slurry is transferred to the catalyst supply vessel (3) via the catalyst transfer line 2. The transfer from the catalyst preparation vessel to the catalyst supply vessel can be carried out batchwise. Preferably, the catalyst supply vessel (3) is arranged at a level higher than the level of the catalyst preparation vessel (1). Thereby, the movement of the catalyst slurry from the catalyst preparation vessel (1) to the catalyst supply vessel (3) is substantially upward. On the other hand, the homogeneous catalyst slurry is taken out from the bottom of the catalyst supply vessel (3) during operation. A part of the taken-out catalyst slurry is transferred to the polymerization reactor (6) via the supply line (5) using, for example, a valveless piston pump (4). The catalyst supply vessel (3) is arranged above the polymerization reactor (6).

[0100] Figure 2 shows another embodiment of the method of the present invention. This method includes two catalyst preparation vessels (11, 12), two catalyst supply vessels (31, 32), two catalyst supply pumps (41, 42), and a polymerization reactor (6). The catalyst slurry of the first catalyst preparation vessel (11) is transferred to the first catalyst supply vessel (31) via the first catalyst transfer line (21), and the catalyst slurry of the second catalyst preparation vessel (12) is transferred to the second catalyst supply vessel (32) via the second catalyst transfer line (22). Preferably, the catalyst supply vessels (31, 32) are arranged at a level higher than the level of the polymerization reactor (6). A part of the catalyst slurry taken out from the catalyst supply vessels (31, 32) is transferred to, for example, two valveless piston pumps (41, 42) via two supply lines (51, 52), and then transferred to the polymerization reactor (6) via two reactor supply lines (71, 72).

[0101] Figure 3 shows another embodiment of the method of the present invention. Figure 3 shows a flow sheet similar to the system shown in Figure 2, but in the system shown in Figure 3, the first and second catalyst transfer lines (211, 212 & 221, 222) connecting the first and second catalyst preparation vessels (11, 12) and the first and second catalyst supply vessels (31, 32) cross each other. The first and second supply lines (511, 512 & 521, 522) from the first and second catalyst supply vessels (31, 32) to the valveless piston pumps (41, 42) also cross each other.

[0102] The catalyst slurry in the first catalyst preparation vessel (11) is transferred to the first catalyst supply vessel (31) via the first catalyst transfer lines (211, 212), thereby passing through the first switching system (23) located between the first part (211) of the first transfer line and the second part (212) of the first transfer line. The switching system (23) is composed of two or more valves and can be set so that the catalyst slurry is transferred to the first catalyst supply vessel (31) via the second part (212) of the first catalyst transfer line or is transferred to the second catalyst supply vessel (32) via the second part (222) of the second catalyst transfer line. The catalyst slurry in the second catalyst preparation vessel (12) is transferred to the first catalyst supply vessel (32) via the first part (221) of the first catalyst transfer line, thereby passing through the first switching system (23). The first switching system (23) can be set so that the catalyst slurry is transferred to the second catalyst supply vessel (32) via the second part (222) of the second catalyst transfer line or is transferred to the first catalyst supply vessel (31) via the second part (212) of the first catalyst transfer line.

[0103] A part of the catalyst slurry taken out from the catalyst supply containers (31, 32) is transferred to the valveless piston pumps (41, 42) via the first and second supply lines (511, 512 & 521, 522) and the second switching system (53), and then transferred to the polymerization reactor (6) via the two reactor supply lines (71, 72). A part taken out from the catalyst supply container (31) is transferred to the second switching system (53) via the first part (511) of the first supply line, and then to the valveless piston pump (41) via the second part (512) of the first supply line, or to the other valveless piston pump (42) via the second part (522) of the second supply line. A part taken out from the catalyst supply container (32) is transferred to the second switching system (53) via the first part (521) of the second supply line, and then transferred to the valveless piston pump (42) via the second part (522) of the second supply line, or may be transferred to the other valveless piston pump (41) via the second part (512) of the first supply line. The desired line can be selected via the switching system. By this method, further flexibility is obtained regarding the preparation and supply of the catalyst slurry.

Explanation of Signs

[0104] <List of Reference Signs> 1 Catalyst Preparation Container 11 First Catalyst Preparation Container 12 Second Catalyst Preparation Container 2 Catalyst Transfer Line 21 First Catalyst Transfer Line 211 First Part of the First Catalyst Transfer Line 212 Second Part of the First Catalyst Transfer Line 22 Second Catalyst Transfer Line 221 First Part of the Second Catalyst Transfer Line 222 Second Part of the Second Catalyst Transfer Line 23 First Switching System 3 Catalyst Supply Container 31 First Catalyst Supply Container 32 Second Catalyst Supply Container 4 Catalyst Supply Pump 41 First catalyst supply pump 42 First catalyst supply pump 5 Supply line 51 First supply line 511 First part of the first supply line 512 Second part of the first supply line 52 Second supply line 521 First part of the second supply line 522 Second part of the second supply line 53 Second switching system 6 Polymerization reactor 7 Reactor supply line 71 First reactor supply line 72 Second reactor supply line Preferred embodiments of the present specification include at least the following. [1] A method for supplying a polymerization catalyst to a polymerization reactor, the method comprising the following steps: (i) forming a catalyst slurry containing an oil and a solid catalyst component in a first catalyst preparation vessel; (ii) transferring the catalyst slurry from the first catalyst preparation vessel to a first catalyst supply vessel; (iii) maintaining the catalyst slurry in the first catalyst supply vessel in a homogeneous state; (iv) taking out a part of the catalyst slurry from the first catalyst supply vessel, preferably continuously taking out the catalyst slurry from the first catalyst supply vessel, and introducing a part of the taken-out catalyst slurry into the polymerization reactor; comprising the oil having a dynamic viscosity of 25 to 1500 mPa * s under the conditions in the first catalyst preparation vessel and the first catalyst supply vessel, the catalyst slurry being transferred downward along a path substantially perpendicular to the reactor from the first catalyst supply vessel. [2] The method according to [1], comprising a second catalyst preparation vessel, and the catalyst slurry being transferred from the first catalyst preparation vessel and the second catalyst preparation vessel to the first catalyst supply vessel via a first catalyst transfer line. [3] The method according to [1], comprising a second catalyst preparation vessel, a first catalyst supply vessel, and a second catalyst supply vessel, the catalyst slurry of the first catalyst preparation vessel being transferred to the first catalyst supply vessel via a first catalyst transfer line, and the catalyst slurry of the second catalyst preparation vessel being transferred to the second catalyst supply vessel via a second catalyst transfer line. [4] The catalyst slurry is transferred from the first catalyst supply vessel and / or the second catalyst supply vessel to the polymerization reactor using at least one valveless piston pump; and / or the catalyst supply vessel is disposed vertically above or obliquely above the polymerization reactor. [5] The oil is white oil, preferably food-approved white oil; and / or the oil has a dynamic viscosity of 30 to 1500 mPa * s, preferably 35 to 990 mPa * s under the conditions in the first catalyst preparation vessel and / or the second catalyst preparation vessel, and the first catalyst supply vessel and / or the second catalyst supply vessel; and / or the catalyst supplied to the first catalyst preparation vessel and / or the second catalyst preparation vessel is dry catalyst powder; and / or the concentration of the catalyst in the slurry is 10 to 40% by weight, preferably 15 to 30% by weight, more preferably 20 to 25% by weight based on the total amount of the slurry. [6] The catalyst is the method according to any one of [1] to [5], selected from the group consisting of Ziegler-Natta catalysts, metallocene catalysts, late transition metal catalysts, and mixtures thereof. [7] The transfer from the first catalyst preparation container to the first catalyst supply container and / or the transfer from the second catalyst preparation container to the second catalyst supply container is carried out batchwise, the method according to any one of [1] to [6]. [8] At least one transfer line can be emptied using oil and / or N 2 The method according to any one of [2] to [7]. [9] In the first catalyst supply container and the second catalyst supply container, the step of monitoring the level of the catalyst slurry using a level sensor; and / or In the first catalyst preparation container and the second catalyst preparation container, the step of monitoring the level of the catalyst slurry using a level sensor The method according to any one of [3] to [8] including.

[10] The following steps: The step of stopping the withdrawal of the catalyst slurry from one of the first catalyst supply container and the second catalyst supply container, and The step of starting the withdrawal of the catalyst slurry from the other of the first catalyst supply container and the second catalyst supply container in response to a signal from the level sensor, The method according to [9] including.

[11] A method for producing an olefin polymer in a polymerization reactor, including the step of supplying a polymerization catalyst to the polymerization reactor by using the method according to any one of [1] to

[10] .

[12] A method for producing an olefin polymer in the polymerization reactor according to

[11] , the following steps: (i) The step of continuously introducing at least one olefin monomer into the polymerization reactor; (ii) Optionally, the step of continuously introducing a diluent and / or hydrogen into the polymerization reactor; (iii) Polymerizing at least one olefin monomer with a polymerization catalyst and operating the polymerization reactor under conditions such that a reaction mixture containing the catalyst, unreacted monomer, formed polymer, and optionally a diluent and / or hydrogen is formed; and (iv) Optionally, the step of taking out a part of the reaction mixture from the polymerization reactor; The method including.

[13] An olefin polymer obtained by the method according to

[11] or

[12] .

[14] A catalyst slurry supply system for producing an olefin polymer in a polymerization reactor, as follows: - A first catalyst preparation container for forming a catalyst slurry containing oil and a solid catalyst component; - A first catalyst supply container for keeping the catalyst slurry in a homogeneous state; - A polymerization reactor; - A first transfer line connecting the first catalyst preparation container to the first catalyst supply container; - A first supply line connecting the first catalyst supply container to the polymerization reactor; comprising, the first supply line is provided with a pump; and the first catalyst supply container is disposed above the polymerization reactor, a system.

[15] The system includes a second catalyst preparation container, the first catalyst preparation container is connected to the first catalyst supply container via the first transfer line, and the second catalyst preparation container is connected to the second catalyst supply container via the second transfer line; and / or the catalyst supply container is disposed above the injection point of the polymerization reactor, preferably vertically above, the system according to

[14] .

Claims

1. A method for supplying a polymerization catalyst to a polymerization reactor, the method comprising the following steps: (i) forming a catalyst slurry containing oil and a solid catalyst component in a first catalyst preparation vessel; (ii) transferring the catalyst slurry from the first catalyst preparation vessel to a first catalyst supply vessel; (iii) maintaining the catalyst slurry in the first catalyst supply vessel in a homogeneous state; (iv) taking out a part of the catalyst slurry from the first catalyst supply vessel and introducing the taken-out part of the catalyst slurry into the polymerization reactor; comprising, The oil has a dynamic viscosity of 25 to 1500 mPa·s under the conditions in the first catalyst preparation container and the first catalyst supply container. ＊ and the catalyst slurry is transferred downward along a path substantially perpendicular from the first catalyst supply vessel to the reactor.

2. The method according to claim 1, comprising a second catalyst preparation vessel, and the catalyst slurry is transferred from the first catalyst preparation vessel and the second catalyst preparation vessel to the first catalyst supply vessel via a first catalyst transfer line.

3. The method according to claim 1, comprising a second catalyst preparation vessel, a first catalyst supply vessel, and a second catalyst supply vessel, wherein the catalyst slurry of the first catalyst preparation vessel is transferred to the first catalyst supply vessel via a first catalyst transfer line, and the catalyst slurry of the second catalyst preparation vessel is transferred to the second catalyst supply vessel via a second catalyst transfer line.

4. The catalyst slurry is transferred from the first catalyst supply vessel and / or the second catalyst supply vessel to the polymerization reactor using at least one valveless piston pump; and / or the catalyst supply vessel is arranged above the injection point of the polymerization reactor. The method according to claim 3.

5. The oil is white oil; and / or The oil has a dynamic viscosity of 30 to 1500 mPa ＊ s under the conditions in the first catalyst preparation container and / or the second catalyst preparation container, and / or the first catalyst supply container and / or the second catalyst supply container; and / or the catalyst supplied to the first catalyst preparation vessel and / or the second catalyst preparation vessel is dry catalyst powder; and / or the concentration of the catalyst in the slurry is 10 to 40% by weight based on the total amount of the slurry. The method according to claim 3.

6. The method according to any one of claims 1 to 5, wherein the catalyst is selected from the group consisting of Ziegler-Natta catalysts, metallocene catalysts, late transition metal catalysts, and mixtures thereof.

7. The transfer from the first catalyst preparation vessel to the first catalyst supply vessel and / or the transfer from the second catalyst preparation vessel to the second catalyst supply vessel are carried out batchwise. The method according to claim 3 or 5.

8. At least one transfer line can be emptied using oil and / or N ２ The method according to any one of claims 2 to 7, which can be emptied using

9. monitoring the level of the catalyst slurry using a level sensor in the first catalyst supply vessel and the second catalyst supply vessel; and / or A step of monitoring the level of the catalyst slurry using a level sensor in the first catalyst preparation container and the second catalyst preparation container The method according to any one of claims 3, 5, or 7, comprising the step of

10. The following steps: A step of stopping the extraction of the catalyst slurry from one of the first catalyst supply container and the second catalyst supply container, and A step of starting the extraction of the catalyst slurry from the other of the first catalyst supply container and the second catalyst supply container in response to a signal from the level sensor, The method according to claim 9, comprising the step of

11. A method for producing an olefin polymer in a polymerization reactor, comprising a step of supplying a polymerization catalyst to the polymerization reactor by using the method according to any one of claims 1 to 10.

12. A method for producing an olefin polymer in the polymerization reactor according to claim 11, comprising the following steps: (i) A step of continuously introducing at least one olefin monomer into the polymerization reactor; (ii) Optionally, a step of continuously introducing a diluent and / or hydrogen into the polymerization reactor; (iii) Polymerizing at least one olefin monomer with a polymerization catalyst and operating the polymerization reactor under conditions such that a reaction mixture containing the catalyst, unreacted monomer, formed polymer, and optionally a diluent and / or hydrogen is formed; and (iv) Optionally, a step of withdrawing a part of the reaction mixture from the polymerization reactor; The method comprising the step of

13. A catalyst slurry supply system for producing an olefin polymer in a polymerization reactor, comprising the following: - A first catalyst preparation container for forming a catalyst slurry containing an oil and a solid catalyst component; - A first catalyst supply container for maintaining the catalyst slurry in a homogeneous state; - A polymerization reactor; - A first transfer line connecting the first catalyst preparation container to the first catalyst supply container; - A first supply line connecting the first catalyst supply container to the polymerization reactor; Comprising The first supply line is provided with a pump; The first catalyst supply container is disposed vertically above the polymerization reactor; and The oil has a dynamic viscosity of 25 to 1500 mPa·s under the conditions in the first catalyst preparation container and the first catalyst supply container, system. ＊ s, system.

14. The system includes a second catalyst preparation container, The first catalyst preparation container is connected to the first catalyst supply container via a first transfer line, and the second catalyst preparation container is connected to the second catalyst supply container via a second transfer line; and / or The catalyst supply container is disposed above the injection point of the polymerization reactor, The system according to claim 13.

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