Olefin polymerization catalyst slurry, process for its preparation and use, and process for the polymerization of propylene

Abstract

The present application relates to the field of olefin polymerization catalyst, discloses an olefin polymerization catalyst slurry and a preparation method and application thereof, and a propylene polymerization method, which comprises the following steps: (1) purifying a prepared catalyst suspension A for olefin polymerization to obtain a purified catalyst suspension B; (2) mixing the catalyst suspension B with inert grease C after removing part of the washing solvent to obtain a mixed liquid D; (3) vacuum stripping the mixed liquid D in the presence of a protective gas to obtain a mixed liquid E; and (4) mixing the mixed liquid E with inert grease C to obtain a catalyst slurry product G. When the catalyst slurry prepared by the method is used in a polymerization reaction, it has good catalytic activity, hydrogen regulation sensitivity and directional ability, produces less polymer fine powder, and has less safety and quality risk.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of olefin polymerization catalysts, in particular to an olefin polymerization catalyst slurry, a preparation method and application thereof, and a propylene polymerization method. BACKGROUND

[0002] Polyolefin synthetic resin is widely used in various industries due to its excellent thermoplasticity, good mechanical properties, corrosion resistance, etc. More than 95% of polypropylene industry still uses Ziegler-Natta (Z-N) propylene polymerization catalyst. The fourth generation Ziegler-Natta propylene polymerization catalyst is still the main catalyst in industrial production and application.

[0003] The catalyst has an important influence on the performance of polypropylene products and production operation. The focus of research and development mainly includes new carriers and process development, internal and external electron donors and additive technology development, etc.

[0004] Commercial olefin polymerization catalysts generally have two packaging forms: dry powder and slurry. The existing slurry catalyst is prepared into dry powder catalyst first, and then inert oil (such as white oil, vaseline, etc.) is added for configuration.

[0005] The existing commercial slurry catalyst mainly includes a main catalyst, a cocatalyst (an alkyl aluminum compound), and an external electron donor. The preparation process steps of the main catalyst generally include the following steps: a. preparation of catalyst dry powder: (1) under the protection of inert gas, the carrier, low-boiling-point alkane, titanium compound, and electron donor are loaded and reacted at a certain temperature, and then the main catalyst is obtained in the low-boiling-point alkane after multiple high-temperature titanium compound treatment and low-boiling-point alkane washing, and most of the low-boiling-point alkane is removed by filtration; (2) under the protection of inert gas, the low-boiling-point alkane in the catalyst is removed by filtration and vacuum drying in a device with stirring and vibration to obtain dry powder, and then the dry powder is prepared into a finished product through screening and multi-batch mixing.

[0006] However, the preparation method of such catalyst slurry has the following disadvantages: (1) long process flow, long preparation period, and high risk of exposure to air during catalyst turnover, mixing, and transfer; (2) in the process of vacuum extraction and screening, the stirring friction of the catalyst in the dry state, the long-term vibration of the particles, and the dry extraction in the negative pressure environment can damage the particle morphology of part of the catalyst, and the broken catalyst is easy to form fine powder in the polymerization reaction, thereby affecting the long-period stable operation of the downstream polyolefin device; (3) there is a high safety risk in the turnover and hoisting process of catalyst screening, mixing, and slurry configuration.

[0007] Therefore, it is urgent to provide an olefin polymerization catalyst slurry preparation method with simple preparation process, which can reduce the risk caused by lifting and material turnover process and reduce the content of fine powder and block in the catalyst slurry. SUMMARY

[0008] The purpose of the present application is to overcome the above-mentioned problems existing in the prior art, and to provide an olefin polymerization catalyst slurry and a preparation method thereof. The method can effectively shorten the process flow and improve the production efficiency; reduce the catalyst crushing and increase the fine polymer powder caused by the friction of the dry powder and the long-term vibration; and reduce the risk caused by lifting and material turnover process. In addition, compared with the catalyst slurry prepared by the existing process, the catalyst slurry prepared by the method has good catalytic activity, hydrogen sensitivity and directional ability when used in polymerization reaction, and produces less fine polymer powder; and the safety and quality risk of the wet drying method used in the present application is smaller, and the production efficiency is significantly improved.

[0009] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a preparation method of an olefin polymerization catalyst slurry, which comprises:

[0010] (1) purifying the prepared catalyst suspension A for olefin polymerization to obtain a purified catalyst suspension B;

[0011] (2) mixing the catalyst suspension B with inert oil C after removing part of the washing solvent to obtain a mixed liquid D;

[0012] (3) vacuum stripping the mixed liquid D in the presence of a protective gas to obtain a mixed liquid E;

[0013] (4) mixing the mixed liquid E with inert oil C to obtain catalyst slurry finished product G.

[0014] The second aspect of the present application provides an olefin polymerization catalyst slurry prepared by the method of the first aspect.

[0015] The third aspect of the present application provides the application of the catalyst slurry of the second aspect in olefin polymerization.

[0016] The fourth aspect of the present application provides a propylene polymerization method, wherein the method comprises: polymerizing propylene in the presence of the catalyst slurry of the present application.

[0017] Through the above technical solution, the present application achieves the following beneficial technical effects:

[0018] (1) The catalyst slurry prepared by the method of the present application is used in propylene polymerization reaction, and the catalyst has good activity, hydrogen sensitivity and directional ability.

[0019] (2) Compared with the existing technology (the process of first preparing dry powder catalyst and then configuring it into slurry catalyst), when the catalyst slurry prepared by the method of the present invention is used for propylene polymerization reaction, less polymer fine powder is produced, thus ensuring the quality of catalyst products.

[0020] (3) The wet drying method used in this invention has lower safety and quality risks and significantly improves production efficiency.

[0021] (4) The preparation method of the present invention does not require catalyst screening, dry powder mixing and other processes, thus avoiding the need for dry powder materials to go through turnover barrel turnover, hoisting and other processes, reducing safety risks such as catalyst exposure and barrel falling. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] The first aspect of this invention provides a method for preparing an olefin polymerization catalyst slurry, the method comprising:

[0024] (1) The catalyst suspension A prepared for olefin polymerization is purified to obtain purified catalyst suspension B.

[0025] (2) After removing part of the washing solvent from the catalyst suspension B, it is mixed with inert oil C to obtain mixture D;

[0026] (3) In the presence of a protective gas, the mixture D is vacuum stripped to obtain mixture E;

[0027] (4) Mix the mixture E with inert oil C to obtain catalyst slurry product G.

[0028] In this invention, the hexane solvent and inert solvent share a similar compatibility property. Hexane within the catalyst pores is dissolved in the inert solvent. The inert solvent fills and protects the catalyst pores while simultaneously forming a protective oil film on the catalyst particle surface. This reduces the adverse effects of long-term stirring friction in the dry state and vacuum conditions on the catalyst, such as damage and agglomeration, thereby better maintaining the catalyst's activity, hydrogen sensitivity, and orientation capability. It also reduces the content of polymer fines.

[0029] In the present application, the preparation method of the catalyst suspension A for olefin polymerization is not particularly limited, and a conventional preparation method in the art can be used. The preparation method is as follows: under the presence of a protective gas and at a certain temperature, a carrier, a low-boiling alkane, a titanium compound, and an electron donor are subjected to a loading reaction, and then subjected to multiple high-temperature titanium compound treatments and low-boiling alkane washing to obtain a suspension of a main catalyst in a low-boiling alkane, and then most of the low-boiling alkane is removed by filtration to obtain the catalyst suspension A.

[0030] In the present application, the low-boiling alkane is a conventional inert alkane in the art, and is preferably a C5-C7 alkane, including at least one of branched or straight-chain alkanes, such as n-pentane, isopentane, hexane, and heptane, and is more preferably hexane.

[0031] In the present application, the low-boiling alkane mainly acts as a solvent during the preparation of the catalyst, can reduce the concentration and reaction rate of the synthesis reaction, and does not participate in the reaction itself. In addition, such low-boiling alkanes are more easily volatilized and removed during subsequent catalyst drying, and are convenient for recycling and reuse.

[0032] In the present application, in order to remove large particles and blocks in the catalyst suspension A, the catalyst suspension A needs to be subjected to a purification treatment, and some catalyst agglomerated particles and irregular materials can be preliminarily filtered and removed through the purification pretreatment.

[0033] According to some embodiments of the present application, in step (1), the purification treatment is filtration.

[0034] Preferably, the filtration conditions include that the screen mesh size is 10-100 mesh, and the filtration pressure is 0.05-0.45 MPa, preferably 0.1-0.3 MPa.

[0035] More preferably, the filtration conditions include that the screen mesh size is 20-70 mesh, and the filtration pressure is 0.1-0.3 MPa.

[0036] In the present application, the inert oil has good chemical stability and oxidation safety performance, and has moderate running viscosity, which is conducive to the stable dispersion of the catalyst slurry. Preferably, the inert oil C is white oil or vaseline.

[0037] According to some embodiments of the present application, the inert oil is selected from at least one of 10# white oil, 15# white oil, 32# white oil, 68# white oil, 100# white oil, or vaseline, and preferably the inert oil is 68# white oil and / or 100# white oil.

[0038] In the present application, the type of white oil is generally classified according to the kinematic viscosity measured at 40℃, such as 68# white oil, which means that the kinematic viscosity of the white oil at 40℃ is 68mm 2 / s.

[0039] According to some embodiments of the present application, in step (2), the method for removing part of the washing solvent comprises: filtering the catalyst suspension B through a sieve with a mesh size of 150-600 to remove most of the supernatant, and then mixing the remaining suspension with the inert oil C.

[0040] In the present application, the purpose of removing most of the supernatant is to directly filter out a large amount of free hexane in the supernatant layer after the catalyst suspension is settled by the movable filter rod, which can effectively reduce the hexane removal time in the subsequent direct preparation process and improve the preparation efficiency.

[0041] During the experiment, the inventors found that when the amount of residual hexane in the mixed solution D is too large, it will cause the hexane removal time to be prolonged in the subsequent preparation process. In order to shorten the preparation time and improve the preparation efficiency, the amount of residual hexane solvent should be controlled within a certain range. When the amount of residual hexane is too small, the catalyst wet material will be sticky. Due to the large surface tension, after adding the inert oil C, stirring will not be smooth, the resistance will be large, the catalyst particles will be broken, and the product stability and continuous production of the device will be affected.

[0042] According to some embodiments of the present application, in step (2), the mass ratio of the inert oil C to the solute in the mixed solution D is (0.5-7):1.

[0043] Preferably, the mass ratio of the inert oil C to the solute in the mixed solution D is (0.9-3):1.

[0044] In the present application, in order to shorten the preparation time and improve the preparation efficiency, it is necessary to further remove the residual low-boiling-point alkanes in the mixed solution D.

[0045] According to some embodiments of the present application, in step (3), the inert gas is nitrogen.

[0046] Preferably, the conditions of the vacuum stripping include: temperature 30-90℃, vacuum degree -100kPa to -40kPa, and time 1-40h.

[0047] More preferably, the conditions of the vacuum stripping include: temperature 50-80℃, vacuum degree -95kPa to -70kPa, and time 4-20h.

[0048] In the present application, when the vacuum stripping conditions meet the above range, the residual low-boiling-point alkane in the mixed solution D can be removed more efficiently, and the performance of each component in the catalyst slurry is also maintained.

[0049] In the present application, in order to quickly measure and regulate the concentration of the catalyst slurry, the inert oil C is mixed with the catalyst slurry twice. In addition, it is found in the experiment that, compared with adding the same amount of white oil at one time, the supernatant viscosity of the catalyst slurry after stratification is lower, the slurry concentration is better regulated, and the packaging and transfer are more favorable.

[0050] In the present application, the catalyst slurry has lower viscosity, and the slurry discharging process is more smooth. The white oil is a mixture, and the low-molecular-weight oil accounts for a small proportion in the white oil, but plays a key role in the viscosity. Since the low-molecular-weight oil is entrained away with hexane in the process of removing hexane by vacuum stripping, the viscosity and concentration of the slurry are increased, which affects the stability of the subsequent discharging. Therefore, by means of twice addition of white oil, the defect can be well solved.

[0051] According to some embodiments of the present application, in step (4), the mass ratio of the inert oil C to the solute in the mixed solution E is (0.2-2):1. Preferably, the mass ratio of the inert oil C to the solute in the mixed solution E is (0.3-1):1.

[0052] In the present application, when the mass ratio of the inert oil C to the solute in the mixed solution E meets the above range, the supernatant viscosity of the catalyst slurry can be effectively regulated, which is favorable for the smooth packaging and discharging of the catalyst, and ensures the continuous and stable production. When the mass ratio of the inert oil C to the solute in the mixed solution E does not meet the above range, the supernatant viscosity of the catalyst slurry is too large, which causes slow filtration speed and affects the continuous production.

[0053] According to some embodiments of the present application, in step (4), the mass ratio of the inert oil C to the solute in the catalyst slurry product G is 1:(1-10). Preferably, the mass ratio of the inert oil C to the solute in the catalyst slurry product G is 1:(1.5-6).

[0054] In the present application, when the mass ratio of the inert oil C to the solute in the catalyst slurry meets the above condition, the supernatant viscosity of the catalyst slurry can be effectively regulated, which is favorable for the smooth packaging and discharging of the catalyst, and ensures the continuous and stable production.

[0055] According to some embodiments of the present application, in step (4), the mixed solution E and the inert oil C are further subjected to packaging and filtration treatment after being mixed.

[0056] Preferably, the temperature of the package is 40-70℃.

[0057] Preferably, the filter screen mesh size is 10-200 mesh, preferably 20-100 mesh, and more preferably 30-70 mesh.

[0058] The second aspect of the present application provides an olefin polymerization catalyst slurry prepared by the method of the first aspect.

[0059] The third aspect of the present application provides the use of the catalyst slurry of the second aspect in olefin polymerization.

[0060] The fourth aspect of the present application provides a method for propylene polymerization, wherein the method comprises: polymerizing propylene in the presence of the catalyst slurry of the present application.

[0061] Preferably, the polymerization conditions include a temperature of 60-100℃, a pressure of 2-3 MPa, and a time of 1-3 h.

[0062] According to a particularly preferred embodiment of the present application, the present application provides a method for preparing an olefin polymerization catalyst slurry, specifically as follows:

[0063] (1) The catalyst suspension A is pressurized to 0.15-0.3 MPa in a reaction kettle, and then is pressurized into a slurry kettle through a filter with a mesh size of 20-70 mesh to obtain a purified catalyst suspension B;

[0064] (2) The catalyst suspension B is press-filtered (filter screen mesh size is 150-600 mesh) in the slurry kettle to remove most of the hexane filtrate, and then the remaining catalyst suspension B is transferred to a slurry preparation kettle through a bottom pipeline, and then dehydrated and deoxygenated inert oil C is added to obtain a mixture D;

[0065] The mass ratio of the inert oil C to the solute in the mixture D is (0.9-3):1.

[0066] (3) Under the protection of nitrogen, the temperature of the slurry kettle is set to 50-80℃, and the pressure is -95 kPa to -70 kPa, and the mixture D is vacuumed for 4-20 h to obtain a mixture E;

[0067] (4) After the mixture E is kept at a constant temperature of 50-80℃ in the slurry kettle for 2-3 h, the dehydrated and deoxygenated inert oil C is added for the second time to adjust the concentration of the catalyst slurry, and then the slurry is packaged at 40-70℃, and then is filtered through a filter F with a mesh size of 30-70 mesh to obtain a catalyst slurry product G1.

[0068] After filtration, the catalyst slurry product is obtained by packaging in a slurry packaging barrel.

[0069] The mass ratio of the inert oil C to the solute in the mixed solution E is (0.3-1):1.

[0070] The mass ratio of the inert oil C to the solute in the catalyst slurry product is 1:(1.5-6).

[0071] The D50 of the particles in the catalyst slurry is 20-80 μm; and the content of hexane in the catalyst slurry is 0.05-3 wt%.

[0072] The application will be described in detail below through examples.

[0073] The content of hexane in the white oil is determined by using Agilent 7890 gas chromatography.

[0074] The determination method of the solid content of the catalyst in the slurry is determined according to Q / SH 361 533 weight method.

[0075] Preparation Example

[0076] The preparation method of the catalyst suspension A is as follows: a certain amount of dialkoxy magnesium carrier (110 kg), 600 L of toluene, 42 kg of di-n-butyl phthalate and 1100 L of titanium tetrachloride are mixed, and after reaction at 110 ℃ for 3 h, the mixture is heat treated with 300 L of titanium tetrachloride and 1200 L of toluene for 3 times at 100 ℃ and washed with 4-5 times of hexane at 60 ℃, to obtain 120 kg of solid catalyst BCM-100H in the catalyst suspension A-790 kg.

[0077] Example 1

[0078] A preparation method of an olefin polymerization catalyst slurry, comprising the following steps:

[0079] (1) The catalyst suspension A is pressurized to 0.1 MPa in a reaction kettle, and then is pressurized into a slurry kettle through a 30-mesh filter to obtain a purified catalyst suspension B;

[0080] (2) After 500 kg of hexane filtrate is filtered out from the catalyst suspension B in the slurry kettle through a moving filter press device (the screen mesh size of the filter is 400 mesh), the remaining catalyst suspension B is transferred to a slurry preparation kettle through a bottom pipeline of the kettle, 180 kg of dehydrated and deoxidized 68# industrial white oil is added, and a mixed solution D is obtained;

[0081] (3) Under the protection of nitrogen, the temperature of the slurry kettle is set to 60 ℃, and the pressure is-80 kPa, and the mixed solution D is vacuumed for 20 h to obtain a mixed solution E;

[0082] (4) After the mixture E is kept at 60°C for 2 hours, 60 kg of 68# industrial white oil treated by dehydration and deoxidization is added for the second time, the catalyst slurry concentration is adjusted, and the slurry is packaged at 45°C. The slurry is filtered through a 60-mesh filter F and then divided and packaged into slurry packaging barrels to obtain catalyst slurry product G1. The solid content of the catalyst in the catalyst slurry product G1 is 30.5 wt%, and the hexane content in the white oil is 0.08%.

[0083] Example 2

[0084] A method for preparing an olefin polymerization catalyst slurry, comprising the following steps:

[0085] (1) The catalyst suspension A is pressurized to 0.12 MPa in a reaction kettle, and then pressurized into a slurry kettle through a 20-mesh filter to obtain purified catalyst suspension B;

[0086] (2) After the catalyst suspension B is filtered out of 550 kg of hexane filtrate through a moving filter press device (the mesh size of the filter is 400 mesh) in the slurry kettle, the remaining catalyst suspension B is transferred to a slurry preparation kettle through a bottom pipeline under the kettle, and 200 kg of 68# industrial white oil treated by dehydration and deoxidization is added for the first time to obtain mixture D;

[0087] (3) Under the protection of nitrogen, the temperature of the slurry kettle is set to 70°C, and the pressure is -80 kPa. The mixture D is vacuumed for 20 h to obtain mixture E;

[0088] (4) After the mixture E is kept at 70°C for 2 hours, 60 kg of 68# industrial white oil treated by dehydration and deoxidization is added for the second time, the catalyst slurry concentration is adjusted, and the slurry is packaged at 45°C. The slurry is filtered through a 60-mesh filter F and then divided and packaged into slurry packaging barrels to obtain catalyst slurry product G2. The solid content of the catalyst in the catalyst slurry product G2 is 29.7 wt%, and the hexane content in the white oil is 0.06%.

[0089] Example 3

[0090] A method for preparing an olefin polymerization catalyst slurry, comprising the following steps:

[0091] (1) The catalyst suspension A is pressurized to 0.12 MPa in a reaction kettle, and then pressurized into a slurry kettle through a 20-mesh filter to obtain purified catalyst suspension B;

[0092] (2) After the catalyst suspension B is filtered out of 600 kg of hexane filtrate through a moving filter press device (the mesh size of the filter is 400 mesh) in the slurry kettle, the remaining catalyst suspension B is transferred to a slurry preparation kettle through a bottom pipeline under the kettle, and 220 kg of 68# industrial white oil treated by dehydration and deoxidization is added for the first time to obtain mixture D;

[0093] (3) Under nitrogen protection, the temperature of the slurry tank was set to 80°C, and the pressure was -90 kPa. The mixed solution D was vacuumed for 7 h to obtain a mixed solution E;

[0094] (4) After the mixed solution E was kept at 80°C for 2 h in the slurry tank, 40 kg of the dehydrated and deoxidized 68# industrial white oil was added for the second time. The catalyst slurry concentration was adjusted, and the slurry was packed at 45°C. The slurry was filtered through a 60-mesh filter F and then was packed into a slurry packing barrel to obtain a catalyst slurry product G3. The solid content of the catalyst in the slurry of the catalyst slurry product G3 was 30.5 wt%, and the hexane content in the white oil was 1.0%.

[0095] Example 4

[0096] The method of Example 1 was followed, except that in step (2), 260 kg of the dehydrated and deoxidized 68# industrial white oil was added at one time to obtain a catalyst slurry product G4. The solid content of the catalyst in the slurry of the catalyst slurry product G4 was 34.4 wt%, and the hexane content in the white oil was 1.0%.

[0097] Example 5

[0098] The method of Example 1 was followed, except that in step (2), the catalyst suspension B was not filtered to remove part of the washing solvent, and was directly mixed with the inert oil C to obtain a catalyst slurry product G5. The solid content of the catalyst in the slurry of the catalyst slurry product G5 was 24.9 wt%, and the hexane content in the white oil was 5.7%.

[0099] Example 6

[0100] The method of Example 1 was followed, except that in step (2), the white oil added was 55 kg (the mass ratio of the inert oil C to the solute in the mixed solution D was 0.46:1) to obtain a catalyst slurry product G6. The solid content of the catalyst in the slurry of the catalyst slurry product G6 was 30.3 wt%, and the hexane content in the white oil was 1.2%.

[0101] Example 7

[0102] The method of Example 1 was followed, except that in step (4), the white oil added was 40 kg (the mass ratio of the inert oil C to the solute in the mixed solution E was 0.33:1) to obtain a catalyst slurry product G7. The solid content of the catalyst in the slurry of the catalyst slurry product G7 was 29.8 wt%, and the hexane content in the white oil was 1.4%.

[0103] Comparative Example 1

[0104] A method for preparing an olefin polymerization catalyst slurry, comprising the following steps:

[0105] (1) The catalyst suspension A was transferred to a drained tank, and the excess hexane liquid was filtered out by moving the filter pressing device. The semi-finished product of dry powder catalyst K1 was obtained by vacuum drying at 50°C for 30 hours and then screening out the block and irregular materials using a 160-mesh sieve.

[0106] (2) 120 kg of dry powder catalyst K1 product was taken, and the dry powder catalyst K1 and the dehydrated and deoxidized 68# industrial white oil were added to the slurry preparation tank at a mass ratio of 30:70. First, the 68# white oil was added, then the catalyst K1 product was added, and then the slurry tank was stirred and mixed at 60°C for 6 hours to obtain the catalyst K1 slurry. The catalyst slurry concentration in the catalyst K1 slurry product was 31.0 wt%, and the hexane content in the white oil was 2.02%.

[0107] Test Example

[0108] The olefin polymerization catalyst slurries G1-G5 and K1 prepared in the above examples and comparative examples were subjected to polymerization reaction, and the catalyst activity, polymer melt index, Ti content (main active component content), isotacticity, and fine powder content were measured. The specific results are shown in Table 1.

[0109] The catalyst slurry activity was measured as follows. In a 5L autoclave, after being fully replaced with propylene gas, 5 mL of triethylaluminum hexane solution (triethylaluminum concentration of 0.5 mmol / mL), 1 mL of cyclohexylmethyl dimethoxysilane (CHMMS) hexane solution (concentration of 0.1 mmol / mL), 2L of liquid propylene, 0.9 MPa of hydrogen, and 6.0 mg of catalyst dry powder (a small amount of catalyst slurry was washed with hexane several times and then dried by nitrogen blowing) were added. The autoclave was closed, and the temperature was raised to 70°C after stirring for 10 min. The polymerization reaction was carried out at an autoclave temperature of 70°C and an autoclave pressure of 3.0 MPa for 1 h. After the reaction was completed, the stirring was stopped, and the unreacted propylene monomer was removed. The polymer was collected and vacuum dried, and the catalyst activity, polymer melt index, and isotacticity were measured.

[0110] The Ti content in the catalyst slurry was measured according to Q / SH 361 526, and the instrument model was 721 spectrophotometer.

[0111] The catalyst activity was measured according to Q / SH 361 528, and the catalyst activity (kg / g Cat) = polymer weight (kg) / solid catalyst component weight (g Cat).

[0112] The polymer melt index (MI) refers to the melt index of the polymer obtained by using the olefin polymerization catalyst for polymerization reaction, and is determined according to GB / T 3682-2000.

[0113] The polymer isotacticity (II) is determined according to GB / T 2412, and the determination method is specifically as follows: 2 g of dry polymer sample is placed in an extractor and extracted with boiling heptane for 6 hours, and then the remaining material is dried to constant weight, and the ratio of the obtained polymer weight (g) to 2 (g) is the isotacticity.

[0114] Polymer fine powder content determination: the polymer powder obtained by polymerization of the catalyst is sieved using a 150 mesh sieve, and the weight percentage of the powder less than 150 mesh is used to represent the fine powder content.

[0115] Table 1

[0116]

[0117]

[0118] As can be seen from the data comparison of Examples 1-7, Comparative Example 1 and Table 1, when the catalyst slurry prepared by the method of the present application is used in propylene polymerization reaction, the catalyst has good activity, hydrogen sensitivity and orientation ability, the activity of the catalyst is above 61.9 kg / g Cat, the MI is above 25.2 g / 10 min, the Ti content is above 2.27 wt%, and the isotacticity is above 98.2%. At the same time, compared with the original process of first preparing a dry powder catalyst and then preparing a slurry catalyst, the catalyst slurry prepared by the present method produces less polymer fine powder when participating in polymerization reaction, and the fine content is 0.2 wt%; and the safety and quality risk of the wet drying method of the present application is smaller, and the production efficiency is significantly improved; the olefin polymerization catalyst slurry prepared by Comparative Example 1 using the prior art has lower activity and hydrogen sensitivity and orientation ability than the catalyst of the present application.

[0119] In summary, according to the technical solution of the present application, the olefin polymerization catalyst slurry prepared has good performance, and compared with the prior art (first prepared into a dry powder catalyst and then prepared into a slurry catalyst process), the production efficiency of the preparation method of the present application is greatly improved, the amount of polymer fine powder is reduced, and the catalyst can be used without screening and dry powder mixing processes, effectively avoiding the need for dry powder materials to be transferred through a transfer barrel, hoisting, etc., reducing the safety risks of catalyst exposure, barrel falling, etc. In addition, the catalyst slurry storage tank can be reused after cleaning, further reducing the waste of resources compared with dry powder catalyst.

[0120] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A process for the preparation of an olefin polymerization catalyst slurry, characterized by, The method comprises: (1) purifying the prepared catalyst suspension A for olefin polymerization to obtain a purified catalyst suspension B; (2) mixing the catalyst suspension B with inert oil C after removing part of the washing solvent to obtain a mixed solution D; (3) vacuum stripping the mixed solution D in the presence of a protective gas to obtain a mixed solution E; (4) mixing the mixed solution E with inert oil C to obtain a catalyst slurry product G; In step (1), the purification treatment is filtration. The filtration conditions include: the screen mesh aperture is 10-100 mesh, and the filtration pressure is 0.1-0.4 MPa. The inert oil is at least one selected from 10# white oil, 15# white oil, 32# white oil, 68# white oil, 100# white oil, or vaseline. In step (2), the mass ratio of the inert oil C to the solute in the mixed solution D is (0.5-7):

1.

2. The method of claim 1, wherein, The filtration conditions include: the screen mesh aperture is 20-70 mesh, and the filtration pressure is 0.15-0.3 MPa.

3. The method of claim 1, wherein, The inert oil is selected from 68# white oil and / or 100# white oil.

4. The method of any of claims 1-3, wherein, In step (2), the method for removing part of the washing solvent includes: filtering the catalyst suspension B through a screen with an aperture of 150-600 mesh to remove most of the supernatant, and then mixing the remaining suspension with the inert oil C.

5. The method of claim 1, wherein, In step (2), the mass ratio of the inert oil C to the solute in the mixed solution D is (0.9-3):

1.

6. The method of any of claims 1-3, wherein, In step (3), the protective gas is nitrogen.

7. The method of any of claims 1-3, wherein, In step (3), the vacuum stripping conditions include: the temperature is 30-90°C, the vacuum degree is -100 to -40 kPa, and the time is 1-40 h.

8. The method of claim 7, wherein, In step (3), the vacuum stripping conditions include: the temperature is 50-80°C, the vacuum degree is -95 to -70 kPa, and the time is 4-20 h.

9. The method of claim 1, wherein, In step (4), the mass ratio of the inert oil C to the solute in the mixed solution E is (0.2-2):

1.

10. The method of claim 9, wherein, In step (4), the mass ratio of the inert oil C to the solute in the mixed solution E is (0.3-1):

1.

11. The method of claim 1, wherein, In step (4), the mass ratio of the inert oil C to the solute in the catalyst slurry product G is 1:(1-10).

12. The method of claim 11, wherein, In step (4), the mass ratio of the inert oil C to the solute in the catalyst slurry product G is 1:(1.5-6).

13. The method of claim 1, wherein, In step (4), after mixing the mixed solution E with the inert oil C, packaging and filtration treatment are further performed.

14. The method of claim 13, wherein, The packaging temperature is 40-70°C.

15. The method of claim 13, wherein, The filtration screen mesh particle size is 10-200 mesh.

16. The method of claim 15, wherein, The filtration screen mesh particle size is 20-100 mesh.

17. The method of claim 16, wherein, The filtration screen mesh particle size is 30-70 mesh.

18. An olefin polymerization catalyst slurry prepared by the method of any one of claims 1-17.

19. The olefin polymerization catalyst slurry of claim 18, wherein, The D50 of the particles in the catalyst slurry is 10-100 μm; and the content of hexane in the catalyst slurry is 0.01-4 wt%.

20. The olefin polymerization catalyst slurry of claim 19, wherein, The D50 of the particles in the catalyst slurry is 20-80 μm; the content of hexane in the catalyst slurry is 0.05-3 wt%.

21. Use of the catalyst slurry according to any one of claims 18-20 in the polymerization of olefins.

22. A process for the polymerization of propylene characterized by, The method comprises: polymerizing propylene in the presence of the catalyst slurry according to any one of claims 18-20.

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