Loop pre-dissolution device and process for polyolefin elastomer production

Abstract

The application relates to the technical field of polyolefin production and discloses a loop pipe pre-dissolution device and process for polyolefin elastomer production. The loop pipe pre-dissolution device comprises a loop pipe mixer, a cooling jacket and a static mixer. The loop pipe mixer is internally formed with a loop flow mixing cavity. The loop pipe mixer is provided with a liquid-phase material inlet and a gas-phase material inlet. The liquid-phase material inlet and the gas-phase material inlet are both connected with the loop flow mixing cavity. The cooling jacket is sleeved on the outer periphery of the loop pipe mixer to form a cooling cavity between the loop pipe mixer and the cooling jacket. The cooling cavity is internally communicated with a cooling medium. The liquid-phase material input pipe is connected with the liquid-phase material inlet. The gas-phase material input pipe is connected with the gas-phase material inlet. The stirrer is arranged in the loop flow mixing cavity. The static mixer is arranged in the loop flow mixing cavity. The application can avoid the local overheating and local over-concentration in traditional dissolution and mixing, improve the stability and safety of dissolution, relieve the problems of back mixing and uneven mixing in the traditional kettle type pre-mixer, and improve the efficiency of polymerization and the insertion rate of comonomer.

Description

Technical Field

[0001] This invention relates to the field of polyolefin production technology, and in particular to a loop pre-melting device and process for the production of polyolefin elastomers. Background Technology

[0002] Polyolefin production processes mainly include three types: gas-phase, slurry, and solution polymerization. Before the advent of metallocene catalysts, the catalysts used for synthesizing polyolefins were primarily heterogeneous catalysts. Furthermore, Zn catalysts exhibited poor high-temperature stability. Therefore, in the last century, most PE industrial plants used gas-phase or slurry processes. With the rapid development of metallocene catalysts, solution polymerization has been increasingly applied to olefin polymerization. Solution polymerization is more advantageous for comonomer insertion and copolymer structure control; for example, polyolefin elastomers (POE) and olefin block copolymers (OBC) are produced using only solution polymerization.

[0003] Polyolefin elastomers (POEs) are obtained by polymerizing ethylene with α-olefins. In the production process, raw material pre-dissolution is essential. Before the comonomer α-olefin and raw material ethylene enter the reactor for polymerization, the ethylene gas needs to be dissolved in the α-olefin solution. The amount of ethylene dissolved determines the comonomer insertion rate, indirectly affecting the reaction activity and product quality. High ethylene solubility significantly increases the comonomer insertion rate, product density and related properties, and fully releases the catalyst activity, reducing the high cost of catalyst consumption. However, the dissolution of ethylene gas in the α-olefin solution releases heat of solution. Heat of solution refers to the heat released under certain temperature and pressure conditions (typically standard conditions of 298 K and 101 kPa). Increased heat of solution leads to increased enthalpy change within the system, reducing the solubility of ethylene in the monomer. Therefore, the release of heat of solution needs to be addressed in the raw material pre-dissolution stage to indirectly improve the solubility of ethylene.

[0004] Existing processes and equipment for pre-solution in the production of polyolefin elastomers typically employ a combination of batch reactors and internal components to reduce dead zones. However, excessive internal components lead to difficulties in cleaning and limited enhancement of mass transfer. Therefore, existing solution polymerization equipment and processes still require further improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a loop pre-dissolving device and process for the production of polyolefin elastomers, which avoids the phenomena of local overheating and local overconcentration that occur in traditional dissolution and mixing processes, thereby improving the stability and safety of dissolution. It also alleviates the problems of backmixing and uneven mixing in traditional batch premixers, improving the efficiency of the polymerization reaction and the comonomer insertion rate, thus enhancing the quality of the polyolefin elastomer.

[0006] The above-mentioned technical objectives of this invention are mainly achieved through the following technical solutions:

[0007] On one hand, the present invention provides a loop pre-melting apparatus for the production of polyolefin elastomers, comprising:

[0008] A loop mixer having a circulating mixing chamber inside, the loop mixer having multiple liquid phase material inlets and at least one gas phase material inlet, the multiple liquid phase material inlets and the gas phase material inlets being connected to the circulating mixing chamber;

[0009] A cooling sleeve is fitted around the outer periphery of the ring mixer to form a cooling cavity between the cooling sleeve and the ring mixer, and a cooling medium flows through the cooling cavity;

[0010] Multiple liquid material input pipes pass through the cooling sleeve and are respectively connected to multiple liquid material inlets;

[0011] At least one gaseous material input pipe passes through the cooling jacket and is connected to at least one of the gaseous material inlets;

[0012] A stirrer is located inside the circulating mixing chamber;

[0013] At least one static mixer is disposed within the circulating mixing chamber.

[0014] The ring pre-dissolving device described in this invention can be used in the production of polyolefin elastomers. It achieves the mixing of liquid and gaseous materials before the materials enter the reactor. The setting of cooling sleeve, stirrer and static mixer avoids the phenomenon of local overheating and local overconcentration that occurs in traditional dissolution and mixing, thereby improving the stability and safety of dissolution.

[0015] The loop pre-dissolving device described in this invention uses a continuous tubular premixer, which can accurately control the mixing temperature and residence time, alleviate the problems of backmixing and uneven mixing in traditional batch premixers, and improve the efficiency of the polymerization reaction and the insertion rate of comonomers, i.e. the quality of polyolefin elastomers.

[0016] In a preferred embodiment of the present invention, a plurality of liquid material inlets are arranged adjacent to each other, and the discharge direction of the plurality of liquid material inlets is the same and they are all arranged along the first circulation direction.

[0017] In this embodiment, the liquid phase material inlets are adjacent and face the same direction, so that each liquid phase material can enter the circulating mixing chamber at the same position in the loop mixer and flow in the same direction to form a circulation in the circulating mixing chamber, thereby improving the mixing effect of each liquid phase material.

[0018] In a preferred embodiment of the present invention, the discharge direction of the gas phase material inlet is opposite to the discharge direction of the liquid phase material inlet.

[0019] In this embodiment, the gaseous material flows countercurrently and mixes with the initially mixed liquid material, which can improve the mixing efficiency of the gaseous and liquid materials and avoid dead zones.

[0020] In a preferred embodiment of the present invention, along the first circulation direction, the stirrer is disposed downstream of each of the liquid phase material inlets and between each of the liquid phase material inlets and the gas phase material inlets.

[0021] In this embodiment, liquid materials are easier to mix than gaseous materials. Preliminary mixing (i.e., mixing of solvent and polymer monomer) can be achieved through simple stirring. Therefore, the stirrer can be placed downstream of and close to each liquid material inlet.

[0022] In a preferred embodiment of the present invention, the ring mixer is further provided with a mixture outlet, which is connected to a mixture output pipe.

[0023] In this embodiment, once the mixture in the circulating mixing chamber reaches the required level, it can be discharged from the circulating mixer through the mixture output pipe.

[0024] In a preferred embodiment of the present invention, the cooling sleeve is connected to a cooling water inlet pipe and a cooling water outlet pipe that communicate with the cooling chamber.

[0025] In this embodiment, the heat of dissolution generated by the dissolution of liquid and gaseous materials can be removed by the cooling water introduced into the cooling chamber, thus avoiding local overheating in the loop mixer.

[0026] In a preferred embodiment of the present invention, the outer periphery of the cooling sleeve is provided with a heat insulation layer.

[0027] In this embodiment, the insulation layer can reduce the impact of ambient temperature on the material pre-dissolving process.

[0028] In a preferred embodiment of the present invention, the loop mixer is provided with at least one bulb, the diameter of which is larger than the diameter of the loop mixer.

[0029] In this embodiment, the bulb can change the flow state of the fluid, promote the mixing of materials, and further improve the mixing effect of the materials.

[0030] In a preferred embodiment of the present invention, the loop mixer includes:

[0031] Two parallel straight pipe sections;

[0032] Two bends are respectively located at both ends of the straight pipe section, and the two ends of the bends are respectively connected to the two straight pipe sections.

[0033] In this embodiment, the loop mixer adopts a racetrack-type structure, including straight pipe sections and curved pipe sections, which facilitates the installation of agitators, static mixers, and bulbs on the loop mixer (the above structure is easier to form or install on the straight pipe section, and the cost is lower). At the same time, the racetrack-type loop mixer allows for flexible control of the material residence time, adjusting the residence time according to the mixing requirements of the material, i.e., the number of times the material circulates in the loop mixer, making operation more flexible.

[0034] In a preferred embodiment of the present invention, both the liquid phase material input pipe and the gas phase material input pipe are equipped with shut-off valves, and the mixed material output pipe is equipped with a ball valve.

[0035] In this embodiment, both the gate valve and the ball valve can control the opening and closing of the corresponding pipeline.

[0036] In a preferred embodiment of the present invention, the loop mixer is further provided with a pressure gauge, a thermometer and a safety valve.

[0037] In this embodiment, the material mixing and dissolving process requires a certain temperature and pressure. Therefore, a pressure gauge is set to monitor the pressure inside the circulating mixing chamber, and a thermometer is set to monitor the temperature inside the circulating mixing chamber. At the same time, a safety valve is set to protect the loop mixer and prevent the loop mixer from exploding due to excessive pressure.

[0038] On the other hand, the present invention also provides a loop pre-melting process for the production of polyolefin elastomers, which is implemented using the loop pre-melting apparatus for the production of polyolefin elastomers as described above, the loop pre-melting process comprising:

[0039] Cooling medium is introduced into the cooling chamber;

[0040] The refined comonomer and refined solvent are introduced into the loop mixer through two liquid material inlet pipes, and the liquid material flows along the first circulation direction and is mixed by a stirrer.

[0041] The refined monomer is introduced into the loop mixer through the gas phase material input pipe. The gas phase material flows in the opposite direction of the first circulation direction to mix with the initially mixed liquid phase material.

[0042] After the liquid and gaseous materials are mixed, they continue to flow along the first circulation direction and are further mixed by a static mixer.

[0043] The present invention relates to the production of polyolefin elastomers. By controlling the order and direction of the introduction of liquid and gaseous materials, the liquid and gaseous materials can be fully mixed and dissolved. This ensures product quality while enhancing the solubility and dissolution rate of the gaseous materials and improving heat removal efficiency, thereby achieving the goal of cost reduction and efficiency improvement.

[0044] In a preferred embodiment of the present invention, the loop pre-dissolution process further includes:

[0045] After the liquid and gaseous materials are fully mixed and dissolved, the mixture is discharged from the loop mixer and introduced into the reactor through the mixture output pipe.

[0046] In a preferred embodiment of the present invention, the refining solvent is a C6-C12 alkane or cycloalkane.

[0047] In a preferred embodiment of the present invention, the refined comonomer is one or more of ethylene, propylene and α-olefin.

[0048] In a preferred embodiment of the present invention, the α-olefin is one or more selected from 1-butene, 1-hexene, 1-octene and 1-decene.

[0049] In a preferred embodiment of the present invention, the refined monomer is one or more of ethylene and propylene.

[0050] In a preferred embodiment of the present invention, the pre-dissolution temperature in the loop mixer is 20°C to 40°C, and the pre-dissolution pressure in the loop mixer is 2.5 MPa to 4.5 MPa. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0052] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0053] Figure 1This is a schematic diagram of the loop pre-melting device for the production of polyolefin elastomers according to the present invention.

[0054] Explanation of reference numerals in the attached figures:

[0055] 10. Loop mixer; 11. Mixing chamber; 12. Bulb; 13. Pressure gauge; 14. Thermometer; 15. Safety valve;

[0056] 20. Cooling sleeve; 21. Cooling chamber; 22. Cooling water inlet pipe; 23. Cooling water outlet pipe;

[0057] 30. Liquid material inlet pipe; 31. Shut-off valve;

[0058] 40. Gas phase material input pipe;

[0059] 50. Mixed material output pipe; 51. Ball valve;

[0060] 60. Stirrer;

[0061] 70. Static Mixer. Detailed Implementation

[0062] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0063] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0065] Implementation Method 1:

[0066] like Figure 1As shown, the present invention provides a loop pre-melting apparatus for the production of polyolefin elastomers, comprising:

[0067] A loop mixer 10 has a circulating mixing chamber 11 inside. The loop mixer 10 is provided with multiple liquid material inlets and at least one gas material inlet. The multiple liquid material inlets and the gas material inlet are all connected to the circulating mixing chamber 11.

[0068] A cooling sleeve 20 is fitted around the outer periphery of the ring mixer 10 to form a cooling chamber 21 between the cooling sleeve 20 and the ring mixer 10, and a cooling medium is circulated in the cooling chamber 21.

[0069] Multiple liquid material input pipes 30 pass through cooling jacket 20 and are respectively connected to multiple liquid material inlets;

[0070] At least one gaseous material inlet pipe 40 passes through the cooling jacket 20 and is connected to at least one gaseous material inlet;

[0071] A stirrer 60 is located inside the circulating mixing chamber 11;

[0072] At least one static mixer 70 is disposed within the circulating mixing chamber 11.

[0073] The ring pre-dissolving device of the present invention can be used for the production of polyolefin elastomers. It can achieve the mixing of liquid and gaseous materials before the materials enter the reactor. The setting of cooling sleeve 20, stirrer 60 and static mixer 70 avoids the phenomenon of local overheating and local overconcentration that occurs in traditional dissolution and mixing, thereby improving the stability and safety of dissolution.

[0074] The loop pre-melting device described in this invention uses a continuous tubular premixer, which can accurately control the mixing temperature and residence time, alleviate the problems of backmixing and uneven mixing in traditional batch premixers, improve the efficiency of the polymerization reaction and the insertion rate of comonomers, thereby improving the quality of polyolefin elastomers.

[0075] The following section will provide a detailed description of the specific structure of each part of the loop pre-melting device for the production of polyolefin elastomers as described in this invention.

[0076] The loop pre-dissolving device of the present invention includes a loop mixer 10, which is the main structure of the loop pre-dissolving device. A circulating mixing chamber 11 for material mixing is formed within the loop mixer 10, allowing the materials to circulate within the circulating mixing chamber 11 and thus achieve mixing between various materials. The loop mixer 10 is typically a pipe-type structure, meaning the cross-section of the circulating mixing chamber 11 is circular. The overall shape of the loop mixer 10 can adopt various structures such as circular, elliptical, and racetrack-shaped.

[0077] In this embodiment, as Figure 1As shown, the ring mixer 10 adopts a racetrack-type structure, which includes two straight pipe sections and two bend sections. The two straight pipe sections are arranged in parallel, and the two bend sections are respectively located at both ends of the straight pipe sections, with the two ends of the bend sections connected to the two straight pipe sections respectively.

[0078] The ring mixer 10 adopts a racetrack-type structure, which facilitates the installation of agitators 60, static mixers 70, and bulbs 12 on the ring mixer 10 (it is more convenient and cost-effective to mold or install them on a straight pipe section). At the same time, the racetrack-type ring mixer 10 allows for flexible control of the material residence time. The residence time, i.e., the number of times the material circulates in the ring mixer 10, can be adjusted according to the mixing requirements of the material, making operation more flexible.

[0079] Specifically, such as Figure 1 As shown, the bend is a 180-degree semi-circular pipe, and the straight and bend sections are connected by flanges. The inner diameters of the straight and bend sections are the same, both ranging from 0.01m to 2.0m; the wall thicknesses of the straight and bend sections are the same, both ranging from 0.002m to 0.03m. The ring mixer 10 is made of one or more of the following materials: stainless steel, titanium alloy, aluminum alloy, zinc alloy, etc., and ceramic materials such as alumina, silicon carbide, and silicon nitride.

[0080] Furthermore, such as Figure 1 As shown, the loop mixer 10 is provided with multiple liquid material inlets, all of which are connected to the circulating mixing chamber 11. Each liquid material inlet is connected to a corresponding liquid material input pipe 30, allowing the liquid material in the liquid material input pipe 30 to enter the circulating mixing chamber 11 through the liquid material inlet. The loop mixer 10 is also provided with at least one gas material inlet, each of which is connected to a corresponding gas material input pipe 40, allowing the gas material in the gas material input pipe 40 to enter the circulating mixing chamber 11 through the gas material inlet.

[0081] Specifically, in this embodiment, the loop mixer 10 is provided with two liquid material inlets, both of which are located on the upper bend section. One of the liquid material inlets is connected to a liquid material input pipe 30 containing a refined solvent, and the other liquid material inlet is connected to a liquid material input pipe 30 containing a refined comonomer. Both the refined solvent and the refined comonomer are liquid materials.

[0082] Preferably, both the liquid phase material input pipe 30 and the gas phase material input pipe 40 are equipped with shut-off valves 31, which can control the opening and closing of the corresponding pipes.

[0083] Furthermore, such as Figure 1As shown, the loop mixer 10 is also provided with a mixture outlet, which is connected to a mixture output pipe 50. After the liquid and gaseous materials are fully mixed in the loop mixing chamber 11, they can enter the mixture output pipe 50 through the mixture outlet and be sent into the reactor for subsequent processing through the mixture output pipe 50.

[0084] Preferably, a ball valve 51 is provided on the mixture output pipe 50, which can control the opening and closing of the corresponding pipe.

[0085] Furthermore, such as Figure 1 As shown, a cooling sleeve 20 is fitted around the outside of the loop mixer 10. The cooling sleeve 20 has the same shape as the loop mixer 10, and the two are coaxially arranged. The diameter of the cooling sleeve 20 is larger than that of the loop mixer 10. A cooling chamber 21 is formed between the cooling sleeve 20 and the loop mixer 10. The cooling chamber 21 has an annular cross-section, and a cooling medium is circulated inside the cooling chamber 21 to absorb the heat of solution generated in the mixing chamber 11.

[0086] Specifically, such as Figure 1 As shown, in this embodiment, the cooling sleeve 20 also adopts a racetrack-shaped structure. The cooling sleeve 20 is connected to a cooling water inlet pipe 22 and a cooling water outlet pipe 23 that communicate with the cooling chamber 21. Both the cooling water inlet pipe 22 and the cooling water outlet pipe 23 are equipped with shut-off valves 31 to control the opening and closing of the pipes. Cooling water can enter the cooling chamber 21 through the cooling water inlet pipe 22. The heat of dissolution generated by the dissolution of liquid and gaseous materials is transferred to the cooling water in the cooling chamber 21. The heated cooling water can be discharged through the cooling water outlet pipe 23, thereby avoiding local overheating in the ring mixer 10. Since the cooling sleeve 20 is sleeved on the outer periphery of the ring mixer 10, the liquid material inlet pipe 30, the gaseous material inlet pipe 40, and the mixed material outlet pipe 50 all pass through the side wall of the cooling sleeve 20.

[0087] In addition, such as Figure 1 As shown, the loop mixer 10 is also equipped with an agitator 60 and a static mixer 70 for mixing materials. In this embodiment, the loop mixer 10 has one agitator 60, which is located in the straight pipe section on the left side of the loop mixer 10; the loop mixer 10 has three static mixers 70, which are located in the two straight pipe sections on the left and right sides of the loop mixer 10. The number of static mixers 70 can be set according to actual needs.

[0088] The agitator 60 mainly consists of an agitator frame, a motor, a reducer, bearings, a sealing device, and agitator blades (only the agitator blades and motor are shown in the figure). The agitator frame is the main body of the agitator 60 and is made of either stainless steel or carbon steel. The motor and reducer have a power rating of 5Hz-50Hz. The bearings support the agitator blades and are made of either cast steel or cast iron. The sealing device is a crucial component preventing leakage from the agitator 60 and is either a mechanical seal or a packing seal. The motor's output shaft passes through the cooling sleeve 20 and the annular mixer 10, extending into the mixing chamber 11. The agitator blades are connected to the end of the output shaft and are shaped as a paddle, spiral, or anchor, with a number of blades ranging from 2 to 10.

[0089] The static mixer 70 is connected to the ring mixer 10 via a flange, serving as a section of the ring mixer 10. The static mixer 70 is one of a mixing drum mixer, a spiral finned mixer, and a rapid reverse mixer, preferably a spiral finned mixer. The static mixer 70 is made of one or more of the following materials: stainless steel, titanium alloy, aluminum alloy, etc., and ceramic materials such as alumina, silicon carbide, and silicon nitride.

[0090] The following will further explain the structure and technical effects of a preferred embodiment of the loop pre-melting apparatus for polyolefin elastomer production described in this invention.

[0091] According to one embodiment of the present invention, such as Figure 1 As shown, two liquid material inlets are arranged adjacent to each other, and the discharge directions of the two liquid material inlets (not shown in the figure) are the same and both are along the first circulation direction. Figure 1 (Middle arrow direction) Setting. The liquid phase material inlets are adjacent and face the same direction, so that each liquid phase material can enter the circulating mixing chamber 11 near the position of the loop mixer 10 and flow in the same direction (first circulating direction) to form a circulation in the circulating mixing chamber 11, thereby improving the mixing effect of each liquid phase material.

[0092] According to one embodiment of the present invention, such as Figure 1 As shown, the discharge direction of the gas phase material inlet is opposite to that of the liquid phase material inlet (not shown in the figure), that is, the gas phase material inlet faces the opposite direction of the first circulation direction. The countercurrent flow of the gas phase material, mixing with the initially mixed liquid phase material, can improve the mixing efficiency of the gas and liquid phase materials and avoid dead zones.

[0093] According to one embodiment of the present invention, such as Figure 1As shown, along the first circulation direction, the stirrer 60 is located downstream of each liquid material inlet and between each liquid material inlet and the gas material inlet. Liquid materials are easier to mix than gas materials, and preliminary mixing (i.e., mixing of solvent and polymer monomer) can be achieved through simple stirring operations. Therefore, it is sufficient to place the stirrer 60 downstream of each liquid material inlet and close to each liquid material inlet.

[0094] According to one embodiment of the present invention, the outer periphery of the cooling sleeve 20 is provided with a heat insulation layer, which can reduce the influence of ambient temperature on the material pre-dissolving process; the heat insulation layer is made of asbestos material.

[0095] According to one embodiment of the present invention, such as Figure 1 As shown, the loop mixer 10 is provided with at least one bulb 12, the diameter of which is larger than the diameter of the loop mixer 10. The bulb 12 can change the flow state of the fluid, promoting the mixing of materials and further improving the mixing effect. In this embodiment, the bulb 12 is disposed on two straight pipe sections of the loop mixer 10. The bulb 12 is integrally formed during the processing of the straight pipe sections, and the diameter of the bulb 12 is 0.015m-2.5m.

[0096] According to one embodiment of the present invention, such as Figure 1 As shown, the loop mixer 10 is also equipped with a pressure gauge 13, a thermometer 14 and a safety valve 15.

[0097] The material mixing and dissolving process requires a certain temperature and pressure. Therefore, a pressure gauge 13 is set to monitor the pressure inside the circulating mixing chamber 11, and a thermometer 14 is set to monitor the temperature inside the circulating mixing chamber 11. At the same time, a safety valve 15 is set to protect the loop mixer 10. When the pressure inside the equipment is too high, the safety valve 15 will open automatically and close automatically when the pressure drops to a safe range, to prevent the loop mixer 10 from exploding due to excessive pressure.

[0098] Implementation Method Two:

[0099] On the other hand, the present invention also provides a loop pre-melting process for the production of polyolefin elastomers, which is implemented using the loop pre-melting apparatus for the production of polyolefin elastomers as described in Embodiment 1, the loop pre-melting process comprising the following steps:

[0100] Step S1: Introduce cooling medium into cooling chamber 21;

[0101] Step S2: The refined comonomer and refined solvent are introduced into the loop mixer 10 through two liquid material input pipes 30 respectively. The liquid material flows along the first circulation direction and is mixed by the stirrer 60.

[0102] Step S3: The refined monomer is introduced into the loop mixer 10 through the gas phase material input pipe 40. The gas phase material flows in the opposite direction of the first circulation direction to mix with the initially mixed liquid phase material.

[0103] Step S4: After the liquid and gaseous materials are mixed, they continue to flow along the first circulation direction and are further mixed through the static mixer 70.

[0104] The loop pre-dissolution process described in this invention is used in the production of polyolefin elastomers. By controlling the order and direction of the introduction of liquid and gaseous materials, the liquid and gaseous materials can be fully mixed and dissolved. This process enhances the solubility and dissolution rate of the gaseous materials while ensuring product quality and improving heat removal efficiency, thereby achieving the goal of cost reduction and efficiency improvement.

[0105] The following section will describe in detail the steps of the loop pre-dissolution process described in this invention.

[0106] In step S1, after cleaning the mixing chamber 11 in the ring mixer 10, all valves are closed; before mixing the materials, the shut-off valves 31 on the cooling water inlet pipe 22 and the cooling water outlet pipe 23 are opened to continuously supply cooling water into the cooling chamber 21, and the agitator 60 and the static mixer 70 are turned on.

[0107] In step S2, after the flow rate of cooling water in the cooling chamber 21 stabilizes, the shut-off valves 31 on the two liquid phase material input pipes 30 are opened, and the refined comonomer (first type of liquid phase material) and the refined solvent (second type of liquid phase material) are respectively introduced into the ring mixer 10 through the two liquid phase material input pipes 30. The refined comonomer and the refined solvent flow along the first circulation direction and are initially mixed by the stirrer 60.

[0108] In step S3, the shut-off valve 31 on the gas phase material input pipe 40 is then opened, and the refined monomer (gas phase material) input pipe is introduced into the loop mixer 10. The gas phase material flows in the reverse direction of the first circulation direction to mix with the initially mixed liquid phase material, thereby improving the mixing efficiency and avoiding dead zones.

[0109] In step S4, after the gaseous and liquid phase materials are initially mixed, the mixture will continue to flow along the first circulation direction. The static mixer 70 changes the flow state of the fluid, making the materials efficiently and uniformly mixed. At the same time, the spherical bubbles 12 on the ring mixer 10 can change the flow state of the fluid, which promotes the mixing of the materials. The heat of solution generated during the mixing process is absorbed and discharged by the cooling water.

[0110] The preferred embodiment of the loop pre-dissolution process of the present invention will be described below.

[0111] According to one embodiment of the present invention, the loop pre-dissolution process further includes:

[0112] Step S5: After the liquid and gaseous materials are fully mixed and dissolved, the mixture is discharged from the loop mixer 10 and introduced into the reactor through the mixture output pipe 50.

[0113] In step S5, after the mixture in the ring mixer 10 reaches the required level for the first time, the ball valve 51 on the mixture output pipe 50 is opened and the ball valve 51 is kept in the normally open state.

[0114] According to one embodiment of the present invention, the refining solvent is a C6-C12 alkane or cycloalkane.

[0115] According to one embodiment of the present invention, the refined comonomer is one or more of ethylene, propylene and α-olefin.

[0116] Furthermore, the α-olefin is one or more of 1-butene, 1-hexene, 1-octene, and 1-decene.

[0117] According to one embodiment of the present invention, the refined monomer is one or more of ethylene and propylene.

[0118] According to one embodiment of the present invention, the pre-dissolution temperature in the loop mixer 10 is 20°C to 40°C, and the pre-dissolution pressure in the loop mixer 10 is 2.5 MPa to 4.5 MPa; preferably, the pre-dissolution temperature in the loop mixer 10 is 25°C to 35°C, and the pre-dissolution pressure in the loop mixer 10 is 3 MPa to 4 MPa.

[0119] In a specific material mixing operation:

[0120] 6 L of refined cyclohexane and 1.8 L of refined octene are added to the loop mixer 10 through the liquid phase material input pipe 30. Then, 0.6 kg of refined ethylene is added to the loop mixer 10 through the gas phase material input pipe 40. The agitator 60 inside the loop mixer 10 has a power of 24.32 Hz and three blades. All parts of the agitator 60 are made of stainless steel. The static mixer 70 is a spiral finned mixer made of carbon steel. At this time, the pressure gauge 13 reads 3.8 MPa, and the thermometer 14 reads 25°C. The cooling water in the cooling chamber 21 removes the dissolution heat. After mixing, the mixture is discharged through the mixture output pipe 50. The composition of the mixture is analyzed using an online chromatography device. The dissolution limit is reached under these conditions in approximately 0.5 hours. At this point, the solubility of ethylene reaches 23.2 g ethylene / 100 g cyclohexane. During the dissolution process, the temperature remains essentially constant (25°C ± 1°C), indicating that the process implemented using the above-described device has excellent heat removal capabilities.

[0121] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A loop pre-melting device for the production of polyolefin elastomers, characterized in that, include: A loop mixer (10) has a circulating mixing chamber (11) inside. The loop mixer (10) is provided with multiple liquid material inlets and at least one gas material inlet. Each of the liquid material inlets and the gas material inlets is connected to the circulating mixing chamber (11). A cooling sleeve (20) is fitted around the outer periphery of the ring mixer (10) to form a cooling cavity (21) between the cooling sleeve (20) and the ring mixer (10), and the cooling cavity (21) is used to carry a cooling medium. Multiple liquid material input pipes (30) pass through the cooling sleeve (20) and are respectively connected to multiple liquid material inlets; At least one gaseous material input pipe (40) passes through the cooling sleeve (20) and is connected to at least one of the gaseous material inlets; A stirrer (60) is provided inside the circulating mixing chamber (11); At least one static mixer (70) is disposed within the circulating mixing chamber (11).

2. The loop pre-melting apparatus for polyolefin elastomer production according to claim 1, characterized in that, Multiple liquid material inlets are arranged adjacent to each other, and the discharge direction of the multiple liquid material inlets is the same and they are all arranged along the first circulation direction in the circulating mixing chamber (11).

3. The loop pre-melting apparatus for polyolefin elastomer production according to claim 2, characterized in that, The discharge direction of the gas phase material inlet is opposite to that of the liquid phase material inlet.

4. The loop pre-melting apparatus for polyolefin elastomer production according to claim 3, characterized in that, Along the first circulation direction, the agitator (60) is located downstream of each of the liquid material inlets and between each of the liquid material inlets and the gas material inlets.

5. The loop pre-melting apparatus for polyolefin elastomer production according to claim 1, characterized in that, The ring mixer (10) is also provided with a mixture outlet, which is connected to a mixture output pipe (50).

6. The loop pre-melting apparatus for polyolefin elastomer production according to claim 1, characterized in that, The cooling sleeve (20) is connected to a cooling water inlet pipe (22) and a cooling water outlet pipe (23) that are connected to the cooling chamber (21).

7. The loop pre-melting apparatus for polyolefin elastomer production according to claim 1 or 6, characterized in that, The outer periphery of the cooling sleeve (20) is provided with a heat insulation layer.

8. The loop pre-melting apparatus for polyolefin elastomer production according to claim 1, characterized in that, The ring mixer (10) is provided with at least one bulb (12), the diameter of which is larger than the diameter of the ring mixer (10).

9. The loop pre-melting apparatus for polyolefin elastomer production according to claim 1, characterized in that, The loop mixer (10) includes: Two parallel straight pipe sections; Two bends are respectively located at both ends of the straight pipe section, and the two ends of the bends are respectively connected to the two straight pipe sections.

10. The loop pre-melting apparatus for polyolefin elastomer production according to claim 5, characterized in that, Both the liquid phase material input pipe (30) and the gas phase material input pipe (40) are equipped with shut-off valves (31), and the mixed material output pipe (50) is equipped with a ball valve (51).

11. The loop pre-melting apparatus for polyolefin elastomer production according to claim 1, characterized in that, The ring mixer (10) is also equipped with a pressure gauge (13), a thermometer (14) and a safety valve (15).

12. A loop pre-melting process for the production of polyolefin elastomers, characterized in that, The loop pre-melting apparatus for the production of polyolefin elastomers according to any one of claims 1-11 is used, wherein the loop pre-melting process includes: Cooling medium is introduced into the cooling chamber (21); The comonomer and solvent are introduced into the loop mixer (10) through two liquid material inlet pipes (30), respectively. The liquid material flows along the first circulation direction and is mixed by the stirrer (60). The monomer is introduced into the loop mixer (10) through the gas phase material input pipe (40), and the gas phase material flows in the opposite direction of the first circulation direction to mix with the initially mixed liquid phase material; After the liquid and gaseous materials are mixed, they continue to flow along the first circulation direction and are further mixed by the static mixer (70).

13. The loop pre-melting process for producing polyolefin elastomers according to claim 12, characterized in that, The loop pre-dissolution process also includes: After the liquid phase material and the gas phase material are fully mixed and dissolved, the mixture is discharged from the ring mixer (10) and introduced into the reactor through the mixture output pipe (50).

14. The loop pre-melting process for the production of polyolefin elastomers according to claim 12, characterized in that, The solvent is a C6-C12 alkane or cycloalkane.

15. The loop pre-melting process for the production of polyolefin elastomers according to claim 12, characterized in that, The comonomer is one or more of ethylene, propylene, and α-olefin.

16. The loop pre-melting process for the production of polyolefin elastomers according to claim 15, characterized in that, The α-olefin is one or more selected from 1-butene, 1-hexene, 1-octene, and 1-decene.

17. The loop pre-melting process for the production of polyolefin elastomers according to claim 12, characterized in that, The monomer is one or more of ethylene and propylene.

18. The loop pre-melting process for the production of polyolefin elastomers according to claim 12, characterized in that, The pre-dissolution temperature in the loop mixer (10) is 20℃~40℃, and the pre-dissolution pressure in the loop mixer (10) is 2.5MPa~4.5MPa.

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