Spiral tube type polymerization reactor

Abstract

The invention belongs to the technical field of polymerization reaction equipment, and provides a spiral tube type polymerization reactor which consists of two sections of spiral tube type reactors, comprising an outer shell, an end socket, a ground support, a cooling medium feeding pipeline, a cooling medium discharging pipeline, a spiral pipeline, a flow guide pipe, a prepolymerization feeding port, a propylene feeding port, a polypropylene material outlet, a polypropylene circulating material feeding port and a heat preservation material. Reaction materials flow in a tube pass, the two spiral tubular reactors are connected through a spiral pipeline, cooling media flow in a shell pass, and the feeding directions of the cooling media of the two reactors are opposite. The heat exchange process of the polymerization reaction is enhanced, the stability of the polymerization reaction process is improved, and meanwhile, the occupied space is saved.

Description

Technical Field

[0001] The invention relates to the technical field of polymerization reaction equipment, in particular to a spiral tube type polymerization reactor. Background Art

[0002] Most polymerization reactions are exothermic processes, and a certain temperature needs to be maintained in the reactor during the reaction. Therefore, the reactor needs to have the functions of controlling temperature and removing heat in time to control the reaction temperature within an appropriate range and ensure the quality of the polymerization product.

[0003] The existing technology is generally divided into kettle reactors and shell-and-tube reactors. Kettle reactors generally use mechanical stirring to increase the turbulence inside the reactor and strengthen the reaction and heat transfer process inside the reactor, but require external heat exchangers for heating and cooling operations, which often results in untimely heat removal and substandard products; shell-and-tube reactors can directly exchange heat inside the reactor, but the mass transfer effect in the tubes is poor, resulting in a larger reactor volume to achieve the same reaction degree.

[0004] CN202530012U discloses a polymerization reactor, which solves the problem of uneven stirring of materials inside the polymerization reactor, which may lead to slurry accumulation and material blockage in the reactor, by designing the vertical distance between the arc edge of the arc plate and the corresponding bottom arc of the reactor and the distance between the outer side of the blade and the reactor wall. However, as a kettle reactor, the heat exchange system is separated from the reaction system. It is impossible to remove heat and control the temperature in time inside the reactor, and it is not suitable for reaction systems with large thermal effects and small heat capacity of reactants.

[0005] CN112969720A discloses a method for preparing ethylene homopolymer or copolymer in a tubular reactor. The invention adopts a tubular reactor to prepare low-density polyethylene (LDPE), and the reaction temperature can be accurately controlled. However, the total effective length of the polymerization reactor described in the invention divided by the number of reaction zones is 230 to 350 m, which requires a larger reactor volume to ensure that the polymerization reaction is fully carried out. Summary of the invention

[0006] The purpose of the present invention is to solve a series of problems such as untimely heat removal during the polymerization reaction of a polymerization reactor, which leads to gradual increase in the temperature in the reactor, excessive polymerization of some monomers in the reactor, blockage of the reactor and the axial flow pump, and large volume of the polymerization reactor.

[0007] The technical solution of the present invention is as follows: a spiral polymerization reactor, comprising a spiral tubular reactor a1 and a spiral tubular reactor b2; both spiral tubular reactors comprise an outer shell 3 and a head 4;

[0008] The outer shell 3 is cylindrical, and both ends of the outer shell 3 are provided with outer heads 4 for sealing; the outer heads 4 are provided with openings for installing a cooling medium feed pipeline 6 and a cooling medium discharge pipeline 7 respectively;

[0009] The inlet of the cooling medium feed pipeline 6 of the spiral tubular reactor a1 is opposite to the inlet of the cooling medium feed pipeline 6 of the spiral tubular reactor b2;

[0010] The spiral pipeline 8 and the flow guide pipe 9 are located inside the outer shell 3 and are coaxial with the outer shell 3;

[0011] The spiral pipeline 8 extends from one end of the spiral tubular reactor b2 to the other end of the spiral tubular reactor b2 and then to the other end of the spiral tubular reactor a1; from the other end of the spiral tubular reactor a1 to one end of the spiral tubular reactor a1, it is back-connected to one end of the spiral tubular reactor b2 to form a circulation loop;

[0012] The spiral pipeline 8 of the spiral tubular reactor b2 is provided with a prepolymerization feed port 10 and a propylene feed port 11 respectively;

[0013] The spiral pipeline 8 of the spiral tubular reactor a1 is provided with a polypropylene material outlet 12 and a polypropylene circulating material feed inlet 13;

[0014] The space between the spiral pipeline 8 and the outer shell 3 is filled with insulation material 14; part of the material from the polypropylene material outlet 12 is extracted as product material, and part of the material enters the axial flow pump for pressurization and then enters the spiral tubular reactor a1 through the polypropylene circulating material feed port 13.

[0015] The prepolymerization feed port 10 and the propylene feed port 11 are arranged at opposite positions to the polypropylene material outlet 12 and the polypropylene circulating material feed port 13 .

[0016] The spiral pipeline 8 has a radius of 100-300 mm, a number of turns of 10-20, and a spiral pitch of 300-600 mm.

[0017] The guide pipe 9 is 6000-8000 mm long and 500-1000 mm in diameter.

[0018] The diameters of the polypropylene material outlet 12 and the polypropylene circulating material feed inlet 13 are 100-300 mm.

[0019] The diameters of the prepolymerization feed inlet 10 and the propylene feed inlet 11 are 100-300 mm.

[0020] The outer shell 3 has a diameter of 2000-3000 mm and a length of 8000-10000 mm.

[0021] The outer sealing head 4 is oval in shape.

[0022] The interior of the spiral pipeline 8 is polished.

[0023] The outer shell 3 is placed horizontally, and a plurality of ground supports 5 are arranged on the side close to the ground to stabilize the spiral polymerization reactor.

[0024] The beneficial effects of the present invention are as follows: the spiral pipeline in the reactor can greatly increase the turbulence degree of the cooling medium in the outer shell and improve the heat exchange coefficient; the reactant flow in the spiral tube reactor and the cooling medium flow section are countercurrently exchanged with each other, and the heat exchange effect is good; the reaction pipeline is spirally wound, saving a lot of space volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the internal transverse section structure of the spiral tubular reactor a of the present invention;

[0026] Figure 2 This is a schematic diagram of the internal transverse section structure of the spiral tubular reactor b of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the connection between the spiral tubular reactor a and the spiral tubular reactor b of the present invention;

[0028] Figure 4 This is a schematic diagram of the internal longitudinal slice structure of the spiral tubular reactor a of the present invention;

[0029] Figure 5 It is a schematic diagram of the internal longitudinal slice structure of the spiral tubular reactor b of the present invention.

[0030] In the figure: 1. spiral tubular reactor a; 2. spiral tubular reactor b; 3. outer shell; 4. end cap; 5. ground support; 6. cooling medium feed pipeline; 7. cooling medium discharge pipeline; 8. spiral pipeline; 9. guide pipe; 10. prepolymerization feed port; 11. propylene feed port; 12. polypropylene material outlet; 13. polypropylene circulating material feed port; 14. thermal insulation material. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are described below in conjunction with the accompanying drawings.

[0032] A spiral polymerization reactor comprises two parts as a whole, namely a spiral tubular reactor 1 and a spiral tubular reactor 2. Both polymerization reactors comprise an outer shell 3 and a head 4. The outer shell is cylindrical and placed horizontally. A plurality of ground supports 5 are arranged on the side close to the ground for stabilizing the spiral polymerization reactor. External heads 4 are provided at both ends of the outer shell 3 for sealing. An opening is provided at the head for installing a cooling medium feed pipeline 6 and a cooling medium discharge pipeline 7.

[0033] The cooling feed inlets of spiral tubular reactors 1 and 2 are opposite.

[0034] The spiral pipeline 8 and the flow guide pipe 9 in the polymerization reactor 1 and 2 are coaxial with the outer shell 3 and are located inside the outer shell 3. The spiral pipeline 8 of the spiral polymerization reactor 1 has two openings, namely, a prepolymerization feed opening 10 and a propylene feed opening 11. The spiral pipeline 8 of the spiral polymerization reactor 2 has a polypropylene material outlet 12 and a polypropylene circulating material feed opening 13.

[0035] A heat-insulating material 14 is filled between the spiral pipeline 8 and the outer shell 3 , and the interior of the spiral pipeline 8 is polished.

[0036] Part of the material at the polypropylene material outlet 12 is taken out as product material, and part of the material enters the axial flow pump for pressurization and then enters the spiral tubular reactor 2 through the inlet 13.

[0037] The spiral polymerization reaction shell 3 has a diameter of 2000-3000 mm and a length of 8000-10000 mm, and is suitable for a pressure of 0.1-4.5 MPa and a reaction temperature of 10-100°C.

[0038] The spiral pipeline 8 has a radius of 100-300 mm, a number of turns of 10-20, and a spiral pitch of 300-600 mm.

[0039] The outer sealing head 4 is oval in shape.

[0040] The guide pipe is 6000-8000 mm long and 500-1000 mm in diameter.

[0041] The diameters of the polypropylene material outlet 12 and the polypropylene circulating material feed inlet 13 are 100-300 mm.

[0042] The diameters of the prepolymerization feed inlet 10 and the propylene feed inlet 11 are 100-300 mm.

[0043] The spiral pipeline 8 and the polypropylene material outlet 12 are connected to the polypropylene circulating material feed inlet 13 to the online detection equipment.

[0044] The present invention provides a spiral polymerization reactor. Figure 3As shown, it includes a spiral tubular reactor a1 and a spiral tubular reactor b2. Both spiral tubular reactors include an outer shell 3 and a head 4. A cooling medium feed pipeline 6 and a cooling medium discharge pipeline 7 are provided on the head. The inlets of the cooling medium feed pipeline 6 of the spiral tubular reactor a1 and the spiral tubular reactor b2 are arranged oppositely; the discharge ports of the cooling medium discharge pipeline 7 of the spiral tubular reactor a1 and the spiral tubular reactor b2 are opposite. A prepolymer feed port 10, a propylene feed port 11, a polypropylene material outlet 12 and a polypropylene circulating material feed port 13 are provided on the outer shell 3. The outer shell 3 is coaxial with the spiral pipeline 8 and the guide tube in the outer shell. The polypropylene material outlet 12 is connected to the inlet of the axial flow pump, and the circulating material outlet 13 is connected to the inlet of the axial flow pump.

[0045] The flow pattern of the spiral polymerization reactor is as follows:

[0046] Prepolymer material enters the spiral tubular reactor a1 through the prepolymer feed port 10, and propylene enters the propylene feed port 11. The reaction material flows along the spiral pipeline 8. The reaction material undergoes polymerization reaction and releases heat in the spiral pipeline 8. The coolant outside the spiral pipeline 8 absorbs heat at the same time to control the reaction temperature. After a certain flow time, the reaction material enters the spiral tubular reactor b2. After flowing a certain distance, part of the reaction material is extracted through the polypropylene material outlet 12, and part of the reaction material flows into the axial flow pump for pressurization and returns to the spiral tubular reactor b2 through the polypropylene circulation material feed port 13, and then flows back to the spiral tubular reactor a1 to form a reaction loop.

[0047] The cooling water enters the two spiral tubular reactors through the cooling medium feed pipeline 6 and leaves the spiral tubular reactors through the cooling medium discharge pipeline 7. The cooling medium flow direction of the spiral tubular reactor a1 is opposite to that of the spiral tubular reactor b2. In the spiral tubular reactor, the flow direction of the cooling medium is always opposite to the flow direction of the material, forming a countercurrent heat exchange in the entire flow section.

[0048] The implementation principle of a spiral polymerization reactor of the present invention is as follows: the polymerization reaction material enters the reactor tube side through the prepolymerization feed port 10 and the propylene feed port 11, and the cooling medium enters the reactor shell side through the cooling medium feed pipeline 6, and the polymerization reaction is carried out at a temperature controlled by the coolant. Since the tube side is spiral and the guide pipe 9 is added in the middle of the spiral pipeline 8, it is beneficial to enhance the turbulence degree of the cooling medium in the shell side and strengthen the reaction and heat exchange process. Since the two spiral tubular reactors are connected by the spiral pipeline 8 and the flow directions of the feed medium are opposite, the flow of the spiral pipeline is always in a countercurrent state with the cooling medium, the operation stability is good, and the spiral pipeline is beneficial to saving space volume.

[0049] Example 1

[0050] The spiral polymerization reactor is used for polypropylene reaction, with a design temperature of 70-80°C and a reaction pressure of 3.5MPa. Cooling water is used as the cooling medium, and the cooling water feed amount of the spiral tube reactor is adjusted according to the polymer discharge temperature. The outer shell 1 of the spiral polymerization reactor has a diameter of 2700mm and a length of 8850mm. The guide pipe is 8000mm long and 1000mm in diameter. The polypropylene material outlet 12 and the circulating material feed inlet 13 have a diameter of 300mm, the spiral pipeline radius is 300mm, the number of turns is 16.5, and the spiral pitch is 500mm. The prepolymer feed inlet 10 and the propylene feed inlet 11 have a diameter of 100-300mm.

Claims

1. A spiral polymerization reactor, characterized in that: The spiral polymerization reactor comprises a spiral tubular reactor a (1) and a spiral tubular reactor b (2); both spiral tubular reactors comprise an outer shell (3) and a sealing head (4); The outer shell (3) is cylindrical, and both ends of the outer shell (3) are provided with outer heads (4) for sealing; the outer heads (4) are provided with openings for installing a cooling medium feed pipeline (6) and a cooling medium discharge pipeline (7) respectively; The inlet of the cooling medium feed pipeline (6) of the spiral tubular reactor a (1) is opposite to the inlet of the cooling medium feed pipeline (6) of the spiral tubular reactor b (2); The spiral pipeline (8) and the flow guide tube (9) are located inside the outer shell (3) and are coaxial with the outer shell (3); The spiral pipeline (8) extends from one end of the spiral tubular reactor b (2) to the other end of the spiral tubular reactor b (2) and then to the other end of the spiral tubular reactor a (1); and from the other end of the spiral tubular reactor a (1) to one end of the spiral tubular reactor a (1), and then is connected back to one end of the spiral tubular reactor b (2) to form a circulation loop; The spiral pipeline (8) of the spiral tubular reactor b (2) is respectively provided with a prepolymerization feed port (10) and a propylene feed port (11); The spiral pipeline (8) of the spiral tubular reactor a (1) is respectively provided with a polypropylene material outlet (12) and a polypropylene circulating material feed inlet (13); A heat-insulating material (14) is filled between the spiral pipeline (8) and the outer shell (3); part of the material from the polypropylene material outlet (12) is extracted as product material, and part of the material enters the axial flow pump for pressurization and then enters the spiral tubular reactor a (1) through the polypropylene circulating material feed port (13).

2. The spiral polymerization reactor according to claim 1, characterized in that: The prepolymerization feed port (10) and the propylene feed port (11) are arranged at opposite positions to the polypropylene material outlet (12) and the polypropylene circulating material feed port (13).

3. The spiral polymerization reactor according to claim 1 or 2, characterized in that: The spiral pipeline (8) has a radius of 100 to 300 mm, a number of turns of 10 to 20, and a spiral pitch of 300 to 600 mm.

4. The spiral polymerization reactor according to claim 3, characterized in that: The flow guide pipe (9) is 6000-8000 mm long and 500-1000 mm in diameter.

5. The spiral polymerization reactor according to claim 1 or 2, characterized in that: The diameters of the polypropylene material outlet (12) and the polypropylene circulating material feed inlet (13) are 100 to 300 mm.

6. The spiral polymerization reactor according to claim 1 or 2, characterized in that: The diameters of the prepolymerization feed inlet (10) and the propylene feed inlet (11) are 100 to 300 mm.

7. The spiral polymerization reactor according to claim 1, characterized in that: The outer shell (3) has a diameter of 2000-3000 mm and a length of 8000-10000 mm.

8. The spiral polymerization reactor according to claim 1, characterized in that: The outer sealing head (4) is elliptical.

9. The spiral polymerization reactor according to claim 1, characterized in that: The interior of the spiral pipeline (8) is polished.

10. The spiral polymerization reactor according to claim 1, characterized in that: The outer shell (3) is placed horizontally, and a plurality of ground supports (5) are arranged on the side close to the ground to stabilize the spiral polymerization reactor.

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