Production system and production method of polyethylene wire drawing material

Abstract

The invention discloses a production system and a production method of a polyethylene wire drawing material. The production system comprises a feeding unit, a polymerization unit and a powder treatment unit, the polymerization unit comprises a stirred tank reactor; a discharge port of the stirred tank reactor is sequentially connected with the external circulation cooler and the circulation feed port through the circulation pump to form a first circulation pipeline; the discharge end of the circulating pump is also connected with a sampling branch; the powder treatment unit comprises a solid-liquid separator, a hexane refining unit and an extrusion granulation unit; a feed port of the solid-liquid separator is communicated with a discharge end of the circulating pump through a sampling branch, a liquid phase outlet of the solid-liquid separator is divided into a first passage and a second passage, and the liquid phase outlet is connected to the stirred tank reactor through the first passage to form a second circulating pipeline; the third circulating pipeline is formed by sequentially connecting the third circulating pipeline to the hexane refining unit and the stirred tank reactor through a second passage; the extrusion granulation unit comprises a mixer and an extruder which are connected in sequence, and a feed port of the mixer is communicated with a solid-phase outlet of the solid-liquid separator.

Description

Technical Field

[0001] The present invention relates to the technical field of polyethylene preparation, and more specifically, to a production system and a production method of polyethylene wire drawing material. Background Art

[0002] Polyethylene (PE) is a thermoplastic resin obtained by polymerization of ethylene. Polyethylene is odorless, non-toxic, and feels like wax. Polyethylene has become the most important polyolefin plastic variety with excellent mechanical properties, processing properties, and chemical resistance, and is widely used in the production of films, packaging, and pipes. Polyethylene can be divided into three types according to its production method: high-pressure polyethylene, medium-pressure polyethylene, and low-pressure polyethylene. The main ones are GPE process, CX process, Innovene G process, Innovene S process, Spherilene C bimodal process, Spherilene process, Hostalen process, Luptec G process, Unipol process, etc. The Hostalen low-pressure slurry polyethylene production process can produce 27 different brands of products, and with the help of excellent additives to modify the powder, it can be used to produce injection molding, blow molding, monofilament / fiber, pipe, and film products. Among them, there is only one parallel mode drawing material product, GF7750M2, and the polyethylene drawing material grade 5000S can only be produced in the Philips process and Innovene S process. Compared with the drawing material GF7750M2, the drawing material grade 5000S has lower density and better tensile strength, and its market application field is wider than that of GF7750M2.

[0003] The Hostalen process mainly consists of three vertical stirred tank reactors. Hexane is used as a dispersant to evenly disperse ethylene, 1-butene, catalyst, and polyethylene particles. The Ziegler-Natta catalyst used is magnesium chloride as a proppant. The polymerization reactor is equipped with 1+5+1 stage stirring paddles. Ethylene, comonomer, hydrogen, catalyst, cocatalyst, hexane, and recovered mother liquor continuously enter the reactor from the bottom. The polymerization reaction occurs rapidly, and the total conversion rate of a single pass is higher than 99%.

[0004] The Hostalen process mainly has reaction mode, reaction temperature, reaction pressure, catalyst addition amount, co-catalyst addition amount, reactor ratio, hydrogen addition amount and comonomer butene addition amount and other main control parameters to control the final product indicators, among which the product density and melt index are used as characteristic attributes of the brand. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a production system and a production method for polyethylene wire drawing material.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A production system for polyethylene wire drawing material, the production system comprising a feeding unit, a polymerization unit and a powder processing unit;

[0008] The feeding unit includes a main catalyst storage tank, a co-catalyst storage tank, a liquid phase reaction raw material feeding device and a gas phase reaction raw material feeding device;

[0009] The polymerization unit comprises a stirred tank reactor; the stirred tank reactor is provided with a main catalyst feed port, a gas phase feed port, a liquid phase feed port, a circulating feed port and a discharge port;

[0010] The main catalyst storage tank is connected to the main catalyst feed port through a pipeline and a metering pump, the co-catalyst storage tank is connected to the liquid phase feed port through a pipeline and a metering pump, the liquid phase feed port is also connected to the liquid phase reaction raw material feeding device, and the gas phase reaction raw material feeding device is connected to the gas phase feed port;

[0011] The discharge port of the stirred tank reactor is connected to the external circulation cooler and the circulation feed port in sequence through a circulation pump to form a first circulation pipeline; the discharge end of the circulation pump is also connected to a sampling branch;

[0012] The powder processing unit includes a solid-liquid separator, a hexane refining unit and an extrusion granulation unit;

[0013] The feed port of the solid-liquid separator is connected to the discharge end of the circulation pump through a sampling branch, and the solid-liquid separator is also provided with a solid phase outlet and a liquid phase outlet, and the liquid phase outlet is divided into a first passage and a second passage;

[0014] The liquid phase outlet is connected to the liquid phase feed port through the first passage to form a second circulation pipeline, and the liquid phase outlet is sequentially connected to the hexane refining unit and the liquid phase feed port through the second passage to form a third circulation pipeline;

[0015] The extrusion granulation unit comprises a mixer and an extruder, the feed inlet of the mixer is communicated with the solid phase outlet, and the discharge port of the mixer is communicated with the feed inlet of the extruder.

[0016] Optionally, the polymerization unit comprises two or more stirred tank reactors arranged in parallel.

[0017] Optionally, the outer wall of the stirred tank reactor is provided with a jacket water cooling device.

[0018] The present invention also discloses a method for producing polyethylene wire drawing material, which adopts the above-mentioned production system and specifically comprises the following steps:

[0019] (1) delivering the main catalyst and the co-catalyst to a stirred tank reactor through metering pumps, respectively, and delivering the liquid phase reaction raw materials and the gas phase reaction raw materials to the stirred tank reactor through a liquid phase feed port and a gas phase feed port, respectively, to mix and perform a polymerization reaction, and controlling the polymerization reaction temperature to 83.5° C. using a jacket water cooling device to obtain a reaction product;

[0020] (2) the reaction product is divided into two streams by a circulation pump, one of which is cooled by an external circulation cooler and then sent to the stirred tank reactor to form a first circulation loop; the other is sent to the solid-liquid separator through a sampling branch for solid-liquid separation to obtain a liquid phase product and a solid phase product;

[0021] (3) dividing the liquid product into two streams, wherein one stream is transported to a stirred tank reactor through a first passage to form a second circulation loop, and the other stream is transported to a hexane refining unit through a second passage to purify hexane, and the resulting purified hexane is transported to a stirred tank reactor through a pipeline to form a third circulation loop;

[0022] (4) The solid phase product is transported to a mixer through a solid phase discharge port, and a compounding agent is added to mix the solid phase product. The obtained product is transported to an extruder through a discharge port of the mixer for extrusion to obtain the polyethylene wire drawing material.

[0023] Optionally, the main catalyst is Z501; the co-catalyst is triethylaluminum; the liquid-phase reaction raw materials include refined hexane and mother liquor; and the gas-phase reaction raw materials include hydrogen, comonomer and ethylene.

[0024] Optionally, the particle size of the polyethylene wire drawing material is 2 mm.

[0025] Optionally, the weight average molecular weight Mw of the polyethylene drawing material is 127,000 to 135,000.

[0026] Optionally, the ethylene is ethylene obtained by removing polar substances from an ethylene refining bed.

[0027] Optionally, the feed pressure of the gas phase reaction raw material is 1.75 MPa to 1.85 MPa.

[0028] Optionally, the polymerization reaction pressure is 0.6 MPa to 0.8 MPa.

[0029] Optionally, the amount of the main catalyst added is 0.75 Mol / h to 0.85 Mol / h, and the pressure is 2.4 MPa to 2.6 MPa.

[0030] Optionally, the amount of the co-catalyst added is 25 Mol / h to 28 Mol / h, the pressure is 2.4 MPa to 2.6 MPa; and the mass fraction of the co-catalyst is 10%.

[0031] Optionally, the amount of hydrogen added is 5.2kg / h to 7.5kg / h, and the pressure is 1.75MPa to 1.85MPa 。

[0032] Optionally, the comonomer is 1-butene, the addition amount of 1-butene is 85kg / h to 130kg / h, and the pressure is 1.75MPa to 1.95MPa.

[0033] Optionally, the compounding agent is LS-03, and the addition amount is 4.45kg / t to 4.55kg / t 。

[0034] Optionally, the volume ratio of gas phase ethylene to liquid phase reaction raw material is 4.4:1.

[0035] Optionally, the mother liquor is a hexane solution containing wax, and the pressure is 1.65 MPa to 1.8 MPa.

[0036] Implementing the embodiments of the present invention will have the following beneficial effects:

[0037] The present invention adopts the Hostalen process technology and adjusts the reaction control parameters to obtain polyethylene drawing materials with the characteristics of high yield, high purity and uniform particle size distribution, thereby expanding the application field of Hostalen process products, enhancing the core competitiveness of polyethylene products and having broad industrialization prospects.

[0038] The production system of the present invention can effectively control the flow rate of the reaction materials, the ratio of the reaction materials, the reaction temperature and the reaction cycle, ensure that the reaction module is compatible and easy to adjust the process parameters, and the assembly is simple so that the cost is low, and it can be scaled up in time to achieve industrial large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a flowchart of a production system of polyethylene wire drawing material according to an embodiment of the present invention.

[0040] Figure 2 This is a flow chart of a production system for another polyethylene wire drawing material according to an embodiment of the present invention.

[0041] Wherein: 1. feeding unit, 11. main catalyst storage tank, 12. co-catalyst storage tank; 2. polymerization unit, 21. main catalyst feed port, 22. gas phase feed port, 23. liquid phase feed port, 24. circulation feed port, 25. discharge port, 26. circulation pump; 27. external circulation cooler, 28. sampling branch, 29. jacket water cooling device; 3. powder processing unit, 31. solid-liquid separator, 32. hexane refining unit, 33. extrusion granulation unit, 311. solid phase outlet, 312. liquid phase outlet, 313. first passage, 314. second passage, 331. mixer, 332. extruder, 34. refined hexane storage tank. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited in any way. The present invention discloses a production system for polyethylene wire drawing materials, such as Figure 1 As shown, the production system includes a feeding unit 1, a polymerization unit 2 and a powder processing unit 3; the feeding unit 1 includes a main catalyst storage tank 11, a co-catalyst storage tank 12, a liquid-phase reaction raw material feeding device and a gas-phase reaction raw material feeding device; the polymerization unit 2 includes a stirred tank reactor; the stirred tank reactor is provided with a main catalyst feed port 21, a gas-phase feed port 22, a liquid-phase feed port 23, a circulation feed port 24 and a discharge port 25; the main catalyst storage tank 11 is connected to the main catalyst feed port 21 through a pipeline and a metering pump, the co-catalyst storage tank 12 is connected to the liquid-phase feed port 23 through a pipeline and a metering pump, the liquid-phase feed port 23 is also connected to the liquid-phase reaction raw material feeding device, and the gas-phase reaction raw material feeding device is connected to the gas-phase feed port 22; the discharge port 25 of the stirred tank reactor is connected to an external circulation cooler 27 and a circulation feed port 24 in sequence through a circulation pump 26 to form a first circulation pipe The discharge end of the circulation pump 26 is also connected to a sampling branch 28; the powder processing unit 3 includes a solid-liquid separator 31, a hexane refining unit 32 and an extrusion granulation unit 33; the feed port of the solid-liquid separator 31 is connected to the discharge end of the circulation pump 26 through the sampling branch 28, and the solid-liquid separator 31 is also provided with a solid phase outlet 311 and a liquid phase outlet 312, and the liquid phase outlet 312 branches out a first passage 313 and a second passage 314; the liquid phase outlet 312 is connected to the liquid phase feed port 23 through the first passage 313 to form a second circulation pipeline, and the liquid phase outlet 312 is connected to the hexane refining unit 32 and the liquid phase feed port 23 in sequence through the second passage 314 to form a third circulation pipeline; the extrusion granulation unit 33 includes a mixer 331 and an extruder 332, the feed port of the mixer 331 is connected to the solid phase outlet 311, and the discharge port of the mixer 331 is connected to the feed port of the extruder 332.

[0043] In a specific embodiment, if Figure 2 As shown, the polymerization unit 2 includes two or more stirred tank reactors arranged in parallel.

[0044] In a specific embodiment, a jacket water cooling device 29 is provided on the outer wall of the stirred tank reactor.

[0045] In a specific implementation, the production system further includes a storage tank 34 for storing hexane treated by the hexane refining unit 32 , so as to provide refined hexane for the polymerization unit 2 .

[0046] Specifically, the main catalyst, the co-catalyst and the reaction raw materials enter the stirred tank reactor from the feed port to undergo polymerization reaction, wherein the outer wall of the reactor is designed with a jacket water cooling device 29, and the slurry composed of polyethylene (powder) and hexane generated by the reaction is discharged from the discharge port 25 in the middle of the stirred tank reactor under the action of the stirred tank reactor, and a stream of slurry is pressurized and sent to the external circulation cooler 27 through the circulation pump 26. The external circulation cooler 27 can also use jacket water for cooling, and circulates to the stirred tank reactor from the circulation feed port 24 at the top of the stirred tank reactor, and is adjusted The reaction temperature is controlled by adjusting the flow of jacket water on the outer wall of the external circulation cooler 27 and the stirred tank reactor. The circulation pump 26 is designed with a sampling branch 28 to send another stream of slurry to the solid-liquid separator 31 of the next unit for solid-liquid separation. A portion of the liquid phase is used as the mother liquor and circulated back to the stirred tank reactor through the second circulation loop according to the formulation requirements. The other portion of the liquid phase enters the hexane refining unit 32 for treatment and then circulates back to the stirred tank reactor through the third circulation loop according to the formulation requirements. The solid phase enters the extrusion granulation unit 33, is mixed with the compounding agent and is extruded and granulated to obtain the final pellets.

[0047] The present invention also discloses a method for producing polyethylene wire drawing material, which adopts the production system of any embodiment of the present invention and specifically comprises the following steps:

[0048] (1) The main catalyst and the co-catalyst are respectively delivered to a stirred tank reactor through a metering pump, and the liquid phase reaction raw materials and the gas phase reaction raw materials are respectively delivered to the stirred tank reactor through a liquid phase feed port and a gas phase feed port to mix and carry out a polymerization reaction, and the temperature of the polymerization reaction is controlled to 83.5° C. by a jacket water cooling device to obtain a reaction product.

[0049] (2) The reaction product is divided into two streams by a circulation pump, one of which is cooled by an external circulation cooler and then sent to a stirred tank reactor to form a first circulation loop; the other is sent to a solid-liquid separator through a sampling branch for solid-liquid separation to obtain a liquid phase product and a solid phase product.

[0050] (3) The liquid product is divided into two streams, one of which is transported to a stirred tank reactor through a first passage to form a second circulation loop, and the other is transported to a hexane refining unit through a second passage for hexane refining, and the resulting refined hexane is transported to a stirred tank reactor through a pipeline to form a third circulation loop.

[0051] (4) The solid phase product is transported to a mixer through a solid phase discharge port, and a compounding agent is added to mix the solid phase product. The obtained product is transported to an extruder through a discharge port of the mixer for extrusion to obtain a polyethylene wire drawing material.

[0052] In a specific embodiment, the main catalyst is Z501; the co-catalyst is triethylaluminum; the liquid-phase reaction raw materials include refined hexane and mother liquor; and the gas-phase reaction raw materials include hydrogen, 1-butene and ethylene.

[0053] In a specific embodiment, step (1) further includes:

[0054] (1.1) A main catalyst solution with a concentration of 0.2 mol / l is prepared and delivered to the main catalyst storage tank 11, and then added to the stirred tank reactor through the main catalyst feed port via a metering pump in a quantitative manner according to the formula ratio.

[0055] (1.2) A promoter with a mass fraction of 10% is prepared and delivered to a promoter storage tank, and then added to the stirred tank reactor through a metering pump and in a quantitative manner according to the formula ratio through a liquid phase feed port.

[0056] In a specific embodiment, the ethylene is ethylene after polar substances are removed through an ethylene refining bed.

[0057] In a specific embodiment, the feed pressure of the gas phase reaction raw material is 1.75 MPa to 1.85 MPa.

[0058] In a specific embodiment, the polymerization reaction pressure is 0.6 MPa to 0.8 MPa.

[0059] In a specific embodiment, the amount of the main catalyst added is 0.75 Mol / h to 0.85 Mol / h, and the pressure is 2.4 MPa to 2.6 MPa.

[0060] In a specific embodiment, the amount of the co-catalyst added is 25 Mol / h to 28 Mol / h, the pressure is 2.4 MPa to 2.6 MPa; and the concentration of the co-catalyst is 10% wt.

[0061] In a specific embodiment, the amount of hydrogen added is 5.2 kg / h to 7.5 kg / h, and the pressure is 1.75 MPa to 1.85 MPa.

[0062] In a specific embodiment, the comonomer is 1-butene, the addition amount of 1-butene is 85 kg / h to 130 kg / h, and the pressure is 1.75 MPa to 1.95 MPa.

[0063] In a specific embodiment, the compounding agent is LS-03, the addition amount is 4.45kg / t to 4.55kg / t, and the composition of LS-03 is shown in Table 1 below.

[0064] Table 1 LS-03 ingredients

[0065]

[0066] In a specific embodiment, the volume ratio of gas phase ethylene to liquid phase reaction raw material is 4.4:1.

[0067] In a specific embodiment, the mother liquid is a hexane solution containing wax, and the pressure is 1.65 MPa to 1.8 MPa.

[0068] In a specific embodiment, the particle size of the polyethylene wire drawing material is 2 mm.

[0069] In a specific embodiment, the weight average molecular weight Mw of the polyethylene drawing material is 127,000-135,000.

[0070] In summary, the production system of the present invention can effectively control the flow rate of the reaction materials, the ratio of the reaction materials, the reaction temperature and the reaction cycle, ensure that the reaction module is compatible with and easy to control the process parameters, and the simple assembly makes the cost low, so as to meet the production needs and realize industrial large-scale production, so that the obtained polyethylene drawing material has the characteristics of high yield, high purity and uniform particle size distribution.

[0071] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A production system for polyethylene wire drawing material, characterized in that: The production system comprises a feeding unit, a polymerization unit and a powder processing unit; The feeding unit includes a main catalyst storage tank, a co-catalyst storage tank, a liquid phase reaction raw material feeding device and a gas phase reaction raw material feeding device; The polymerization unit comprises a stirred tank reactor; the stirred tank reactor is provided with a main catalyst feed port, a gas phase feed port, a liquid phase feed port, a circulating feed port and a discharge port; The main catalyst storage tank is connected to the main catalyst feed port through a pipeline and a metering pump, the co-catalyst storage tank is connected to the liquid phase feed port through a pipeline and a metering pump, the liquid phase feed port is also connected to the liquid phase reaction raw material feeding device, and the gas phase reaction raw material feeding device is connected to the gas phase feed port; The discharge port of the stirred tank reactor is connected to the external circulation cooler and the circulation feed port in sequence through a circulation pump to form a first circulation pipeline; the discharge end of the circulation pump is also connected to a sampling branch; The powder processing unit includes a solid-liquid separator, a hexane refining unit and an extrusion granulation unit; The feed port of the solid-liquid separator is connected to the discharge end of the circulation pump through a sampling branch, and the solid-liquid separator is also provided with a solid phase outlet and a liquid phase outlet, and the liquid phase outlet is divided into a first passage and a second passage; The liquid phase outlet is connected to the liquid phase feed port through the first passage to form a second circulation pipeline, and the liquid phase outlet is sequentially connected to the hexane refining unit and the liquid phase feed port through the second passage to form a third circulation pipeline; The extrusion granulation unit comprises a mixer and an extruder, the feed inlet of the mixer is communicated with the solid phase outlet, and the discharge port of the mixer is communicated with the feed inlet of the extruder.

2. The production system of polyethylene wire drawing material according to claim 1, characterized in that: The polymerization unit comprises two or more stirred tank reactors arranged in parallel.

3. The production system of polyethylene wire drawing material according to claim 1, characterized in that: The outer wall of the stirred tank reactor is provided with a jacket water cooling device.

4. A method for producing polyethylene wire drawing material, characterized in that: The production system according to any one of claims 1 to 3 comprises the following steps: (1) delivering the main catalyst and the co-catalyst to a stirred tank reactor through metering pumps, respectively, and delivering the liquid phase reaction raw materials and the gas phase reaction raw materials to the stirred tank reactor through a liquid phase feed port and a gas phase feed port, respectively, to mix and perform a polymerization reaction, and controlling the polymerization reaction temperature to 83.5° C. using a jacket water cooling device to obtain a reaction product; (2) the reaction product is divided into two streams by a circulation pump, one of which is cooled by an external circulation cooler and then sent to the stirred tank reactor to form a first circulation loop; the other is sent to the solid-liquid separator through a sampling branch for solid-liquid separation to obtain a liquid phase product and a solid phase product; (3) dividing the liquid product into two streams, wherein one stream is transported to a stirred tank reactor through a first passage to form a second circulation loop, and the other stream is transported to a hexane refining unit through a second passage to purify hexane, and the resulting purified hexane is transported to a stirred tank reactor through a pipeline to form a third circulation loop; (4) The solid phase product is transported to a mixer through a solid phase discharge port, and a compounding agent is added to mix the solid phase product. The obtained product is transported to an extruder through a discharge port of the mixer for extrusion to obtain the polyethylene wire drawing material.

5. The production method according to claim 4, characterized in that: The main catalyst is Z501; The co-catalyst is triethylaluminum; The liquid phase reaction raw materials include refined hexane and mother liquor; The gas phase reaction raw materials include hydrogen, comonomer and ethylene; The particle size of the polyethylene wire drawing material is 2 mm; The weight average molecular weight Mw of the polyethylene drawing material is 127,000-135,000.

6. The production method according to claim 5, characterized in that The ethylene is the ethylene obtained by removing polar substances from an ethylene refining bed.

7. The production method according to claim 5, characterized in that: The feed pressure of the gas phase reaction raw material is 1.75MPa to 1.85MPa; The polymerization reaction pressure is 0.6MPa to 0.8MPa; The amount of the main catalyst added is 0.75Mol / h to 0.85Mol / h, and the pressure is 2.4MPa to 2.6MPa; The amount of the co-catalyst added is 25Mol / h to 28Mol / h, the pressure is 2.4MPa to 2.6MPa; the mass fraction of the co-catalyst is 10%; The amount of hydrogen added is 5.2kg / h to 7.5kg / h, and the pressure is 1.75MPa to 1.85MPa; The comonomer is 1-butene, the addition amount of the 1-butene is 85kg / h to 130kg / h, and the pressure is 1.75MPa to 1.95MPa.

8. The production method according to claim 5, characterized in that: The compounding agent is LS-03, and the addition amount is 4.45kg / t to 4.55kg / t; The volume ratio of gas phase ethylene to liquid phase reaction raw materials is 4.4:1; The mother liquor is a hexane solution containing wax, and the pressure is 1.65MPa-1.8MPa.

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