PK polymerization system and process

Abstract

A PK polymerization system comprises a polymerization kettle, an extraction kettle and an extraction tower, a raw material inlet, a catalyst inlet and a first vapor phase outlet are formed in the top of the polymerization kettle, the raw material inlet is connected with an ethylene source, a propylene source, a carbon monoxide source and an N-methyl pyrrolidone source through a micro-interface reactor, and the catalyst inlet is connected with a catalyst source. The vapor phase outlet is connected with a first gas-liquid separator, a kettle bottom discharge port of the polymerization kettle supplies materials to the extraction kettle, the top of the extraction kettle is provided with a desalted water inlet and a second vapor phase outlet, the second vapor phase outlet is connected with a second gas-liquid separator, and a kettle bottom discharge port of the extraction kettle supplies materials to the extraction tower. Gas-phase outlets of the first gas-liquid separator and the second gas-liquid separator flow back to the polymerization kettle through a recovery compressor and a cooler, liquid-phase outlets of the first gas-liquid separator and the second gas-liquid separator flow back to the polymerization kettle and the extraction kettle respectively, and a tower bottom discharge port of the extraction tower discharges PK to the outside. The continuous production device is simple in structure and low in maintenance cost, continuous production of the PK polyketone resin is achieved, and the competitiveness of the polyketone resin in the engineering plastic market is improved.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and in particular to a PK polymerization system and process. Background Art

[0002] PK is polyketone resin, a hard and dense material with a smooth, white and shiny surface. It has a high elastic modulus, high rigidity and hardness, and its specific strength and specific rigidity are close to those of metals. It also has a low friction coefficient, is wear-resistant, and has good dimensional stability. Polyketone resin can partially replace copper, zinc, aluminum, steel and other metals and is widely used in automobiles, machinery manufacturing, precision instruments, office appliances, military and other industries. Polyketone resin has the characteristics of high hardness and wear resistance, so it is widely used in the manufacture of various gears, rollers, bearings, conveyor belts, springs, cams, bolts, and various pump bodies, housings, impeller friction bearings and other mechanical equipment structural parts.

[0003] PK is a linear crystalline polymer obtained by the alternating copolymerization of carbon monoxide, ethylene and propylene. At present, the polymerization system of PK is an intermittent design, which makes it impossible to keep the polymerization time consistent. The molecular weight of the polymerization products of different batches is different and the distribution is wide, making it difficult to ensure the quality and performance stability.

[0004] Therefore, it is an urgent problem to be solved by those skilled in the art to design a polymerization system for PK polyketone resin that ensures stable quality and performance so as to improve the market competitiveness of PK polyketone resin. Summary of the invention

[0005] One of the purposes of the present invention is to provide a PK polymerization system in view of the deficiencies of the prior art, which has a simple structure and low maintenance cost, realizes the continuous production of PK polyketone resin, reduces equipment investment, and improves the competitiveness of polyketone resin in the engineering plastics market.

[0006] The second object of the present invention is to provide a process for synthesizing PK using the above-mentioned polymerization system, which has a simple process and is easy to operate, and can synthesize PK products with stable quality and performance.

[0007] The technical scheme for achieving one of the purposes of the present invention is: a PK polymerization system, comprising a polymerization kettle, an extraction kettle, and an extraction tower, wherein the polymerization kettle and the extraction kettle are both provided with a heat exchange interlayer and an agitator, a raw material inlet, a catalyst inlet, and a first vapor phase outlet are provided on the top of the polymerization kettle, the raw material inlet is connected to an ethylene source, a propylene source, a carbon monoxide source, and an N-methylpyrrolidone source through a microinterface reactor, the catalyst inlet is connected to the catalyst source, the vapor phase outlet is connected to a first gas-liquid separator, and a bottom discharge port of the polymerization kettle supplies the extraction kettle, a desalted water inlet and a second vapor phase outlet are provided on the top of the extraction kettle, the desalted water inlet is connected to a desalted water source, the second vapor phase outlet is connected to a second gas-liquid separator, and the bottom discharge port of the extraction kettle supplies the extraction tower, the gas phase outlets of the first gas-liquid separator and the second gas-liquid separator are refluxed to the polymerization kettle through a recovery compressor and a cooler, the liquid phase outlets are refluxed to the polymerization kettle and the extraction kettle respectively, and the bottom discharge port of the extraction tower discharges the PK polymer to the outside.

[0008] The tops of the extraction kettle and the extraction tower are both provided with inert gas regulating valves to discharge inert purge gas to the outside.

[0009] The extraction tower is provided with a plurality of first heat exchange plates and second heat exchange plates spaced apart in the height direction, each heat exchange plate is provided with a heat exchange cavity, the cross section of the first heat exchange plate is hook-shaped, the cross section of the second heat exchange plate is figure eight-shaped, the projections of the two extended ends of the first heat exchange plate are located on the adjacent second heat exchange plate, and the two extended ends of the second heat exchange plate are located on the adjacent first heat exchange plate.

[0010] The feed port of the extraction tower is located in the middle of the side wall, and the upper side wall of the extraction tower is provided with a solvent recovery port to discharge the solvent to the outside.

[0011] The technical solution for achieving the second object of the present invention is: a process for synthesizing PK using any of the above-mentioned polymerization systems, comprising the following steps:

[0012] 1) Ethylene, propylene, carbon monoxide and N-methylpyrrolidone are mixed in a microinterface reactor and then fed into a polymerization kettle, and a catalyst is fed into a polymerization kettle;

[0013] 2) Control the temperature to 80°C, the pressure to 4.0MPa(G), and the polymerization time to 0.9-1h to complete the polymerization reaction;

[0014] 3) The temperature in the extraction kettle is controlled to be 80°C and the pressure is controlled to be 3.0MPa(G), and the mixed material that has completed the polymerization reaction in the polymerization kettle is sent into the extraction kettle under the action of differential pressure;

[0015] 4) Desalted water is sent into the extraction kettle to terminate the polymerization reaction;

[0016] 5) The mixture after the polymerization reaction is terminated in the extraction kettle is sent to the middle part of the extraction tower. The hook-shaped plates and the figure-eight plates are arranged alternately in the extraction tower. Hot water at 85°C flows in the cavity of the plates. The temperature of the extraction tower is controlled at 80°C±2 by controlling the flow rate of hot water. A solvent-water mixture is obtained at the top of the tower, and a polymer-solvent mixture is obtained at the bottom of the tower.

[0017] Step 1) the molar ratio of carbon monoxide to the sum of ethylene and propylene is 1:1, the molar ratio of ethylene to propylene is 56-94:6-46, preferably 9:1, the mass ratio of N-methylpyrrolidone to the sum of ethylene, propylene and carbon monoxide is 8:2, the catalyst is an anionic organic metal complex formed by palladium acetate as the main catalyst, 4,6-dihydroxy-2-methylpyrimidine as the ligand, maleic acid as the anionic co-catalyst, and N-methylpyrrolidone as the catalyst solvent, and the added amount is 22.63% of the sum of the mass of carbon monoxide, ethylene and propylene.

[0018] Step 1) The catalyst preparation method is:

[0019] a) dissolving palladium acetate, 4,6-dihydroxy-2-methylpyrimidine and maleic acid respectively with N-methylpyrrolidone;

[0020] b) controlling the temperature to 80-90° C., mixing and stirring the palladium acetate solution and the 4,6-dihydroxy-2-methylpyrimidine solution for 3 hours, wherein the molar ratio of palladium acetate to 4,6-dihydroxy-2-methylpyrimidine is 1:1.5-3;

[0021] c) adding maleic acid solution, stirring and reacting for 2 hours to obtain a mixture containing a catalyst, wherein the molar ratio of palladium acetate to maleic acid is 1:3-21.

[0022] The molar ratio of the desalted water and N-methylpyrrolidone added in step 4) is 2:1.

[0023] The above technical solution has the following beneficial effects:

[0024] 1. The polymerization system of the present invention comprises a polymerization kettle, an extraction kettle and an extraction tower, wherein the polymerization kettle is used to provide the main place for the polymerization reaction of raw materials, the extraction kettle is used to quench the polymerization reaction, ensure the quality and performance of the product, and is used to separate most of the solvents to achieve the recycling of the solvents, and the extraction tower is used to separate the solvents, water and polymers, which can effectively reduce the cost of subsequent purification of the polymers. The polymerization kettle and the extraction kettle are both provided with a heat exchange interlayer and an agitator to control the temperature and mix the materials to meet the actual needs. The top of the polymerization kettle is provided with a raw material inlet, a catalyst inlet and a first vapor phase outlet, and the raw material inlet is connected to an ethylene source, a propylene source, a carbon monoxide source and an N-methylpyrrolidone source through a microinterface reactor, so that the raw material and the solvent form microdroplets, which can greatly increase the reaction speed of the reaction system, shorten the polymerization residence time, inhibit side reactions and increase the product yield. The catalyst inlet is connected to the catalyst source to provide a catalyst, and usually, the catalyst is also dissolved in a solvent. The vapor phase outlet is connected to a first gas-liquid separator. The bottom discharge port of the polymerization kettle feeds the extraction kettle. The top of the extraction kettle is provided with a desalted water inlet and a second vapor phase outlet. The desalted water inlet is connected to a desalted water source for quenching the polymerization reaction and separating the solvent and polymer therein. The second vapor phase outlet is connected to a second gas-liquid separator. The bottom discharge port of the extraction kettle supplies the extraction tower. The gas phase outlets of the first gas-liquid separator and the second gas-liquid separator are refluxed to the polymerization kettle through a recovery compressor and a cooler to ensure the stability of the pressure of the polymerization kettle and improve the utilization rate of the raw materials. The liquid phase outlets are refluxed to the polymerization kettle and the extraction kettle respectively to improve the utilization rate of the raw materials. The bottom discharge port of the extraction tower discharges the PK polymer to the outside.

[0025] 2. The polymerization process of the present invention uses N-methylpyrrolidone as a solvent, which has the advantages of good solubility, high boiling point, good stability, low corrosiveness, low viscosity and low volatility, and can effectively reduce the side reaction with the raw material maleic acid, improve the utilization rate of raw materials, and reduce the difficulty of separation. Desalted water is used as an extractant to separate the polymer and the solvent under mild conditions, and the decomposition of the polymer is minimized. Specifically, N-methylpyrrolidone (NMP), organic acid maleic acid, and 4,6-dihydroxy-2-methylpyrimidine are easily soluble in water. The solvent N-methylpyrrolidone (NMP) is separated from the polymer by water washing, and the separation process is safer and easier. Although the main catalyst palladium acetate is insoluble in water, it can be entrained by the solvent (N-methylpyrrolidone) to enter the water phase, creating good conditions for subsequent solvent recovery and palladium metal recovery.

[0026] 3. The polymerization process of the present invention can reduce the melting point of PK polyketone resin by controlling the amount of propylene added, so that the melting point temperature is far away from the cross-linking temperature of the polyketone resin, and realize extrusion blow molding processing without cross-linking, and can ensure that the comprehensive indicators of the physical and chemical properties of the polyketone resin are good, and the market application is relatively wide.

[0027] Further description is given below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a connection schematic diagram of the polymerization system of the present invention.

[0029] In the accompanying drawings, 1 is a polymerization kettle, 11 is a raw material inlet, 12 is a catalyst inlet, 13 is a first vapor phase outlet, 2 is an extraction kettle, 21 is a desalted water inlet, 22 is a second vapor phase outlet, 3 is an extraction tower, 31 is a first heat exchange plate, 32 is a second heat exchange plate, 4 is a micro-interface reactor, 5 is a first gas-liquid separator, 6 is a second gas-liquid separator, 7 is a recovery compressor, and 8 is a cooler. DETAILED DESCRIPTION

[0030] In the present invention, 2.9 t / h of ethylene, 0.5 t / h of propylene, 3.23 t / h of carbon monoxide and 53.1 t / h of polymerization solvent NMP are used and enter the polymerization kettle through the microinterface generator.

[0031] Example 1

[0032] The PK polymerization system includes a polymerization kettle 1, an extraction kettle 2, and an extraction tower 3. The polymerization kettle 1 and the extraction kettle 2 are both provided with a heat exchange interlayer and an agitator. A raw material inlet 11, a catalyst inlet 12, and a first vapor phase outlet 13 are provided on the top of the polymerization kettle 1. The raw material inlet 11 is connected to an ethylene source, a propylene source, a carbon monoxide source, and an N-methylpyrrolidone source through a microinterface reactor 4. The catalyst inlet 12 is connected to a catalyst source. The catalyst source also uses N-methylpyrrolidone as a solvent, so that the catalyst is added to the polymerization kettle in the form of a solution. The first vapor phase outlet 13 is connected to a first gas-liquid separator 5. The discharge port at the bottom of the polymerization kettle 1 supplies the extraction kettle 2. Usually, a safety valve is also provided on the top of the polymerization kettle, and the downstream end of the safety valve is connected to the gas phase outlet of the first gas-liquid separator. The top of the extraction kettle 2 is provided with a desalted water inlet 21 and a second vapor phase outlet 22, the desalted water inlet 21 is connected to a desalted water source, the second vapor phase outlet 22 is connected to a second gas-liquid separator 6, and the bottom discharge port of the extraction kettle 2 supplies the extraction tower 3. Usually, a safety valve is also provided on the top of the extraction kettle, and the downstream end of the safety valve is connected to the gas outlet of the second gas-liquid separator. In addition, the bottom discharge port of the extraction kettle supplies the extraction tower through the extraction kettle discharge pump, and the feed port of the extraction tower 3 is located in the middle of the side wall. The upper side wall of the extraction tower 3 is provided with a solvent recovery port to discharge the solvent to the outside. In this embodiment, a plurality of first heat exchange trays 31 and second heat exchange trays 32 are arranged in the extraction tower 3 at intervals along the height direction. A heat exchange cavity is arranged in each heat exchange tray. The cross section of the first heat exchange tray 31 is hook-shaped, and the cross section of the second heat exchange tray 32 is figure eight-shaped. The projections of the two extended ends of the first heat exchange tray are located on the adjacent second heat exchange tray, and the two extended ends of the second heat exchange tray are located on the adjacent first heat exchange tray. The gas phase outlets of the first gas-liquid separator 5 and the second gas-liquid separator 6 are refluxed to the polymerization kettle 1 through the recovery compressor 7 and the cooler 8, and the liquid phase outlets are refluxed to the polymerization kettle 1 and the extraction kettle 2 respectively. The bottom discharge port of the extraction tower 3 discharges the PK polymer to the outside.

[0033] Furthermore, in order to balance the amount of inert gas in the system, the tops of the extraction kettle 2 and the extraction tower 3 are both provided with inert gas regulating valves to discharge the inert purge gas to the outside.

[0034] The equipment parameters are as follows:

[0035]

[0036]

[0037] Example 2

[0038] The polymerization system of Example 1 was used to continuously synthesize PK polymer:

[0039] 1) 2.9t / h of ethylene, 0.5t / h of propylene, 3.23t / h of carbon monoxide and 53.1t / h of polymerization solvent NMP are produced outside the boundary zone at a pressure of 4.1MPa(G), and 50-100μm spherical bubbles are formed in the gas-liquid two phases in the microinterface generator;

[0040] 2) The operating temperature of the polymerization reactor is 80°C and the operating pressure is 4.0MPa(G);

[0041] 3) 1.5 t / h of catalyst was continuously added into the polymerization kettle, and the polymerization time was controlled to be 1 h;

[0042] 4) The outlet flow rate of the polymerization kettle is 61.2 t / h, the operating temperature of the extraction kettle is 80°C, and the operating pressure is 3.0 MPa(G);

[0043] 5) The top of the extraction kettle 6 is connected to the desalted water inlet, with a flow rate of 19.3 t / h, and the polymerization is terminated. Most of the solvent NMP enters the water. The flow rate of the extraction kettle discharge pump 8 is 80.5 t / h.

[0044] 6) The mixed material after the polymerization reaction is terminated in the extraction kettle is sent to the middle of the extraction tower. The hook-shaped plates and the figure-eight-shaped plates are arranged alternately in the extraction tower, and 85°C hot water flows in the plate cavity. The temperature of the extraction tower is controlled at 80°C±2 by controlling the flow rate of hot water, and a solvent-water mixture is obtained at the top of the tower, and a polymer-solvent mixture is obtained at the bottom of the tower.

[0045] The bottom discharge of the extraction tower has a polymer content of 70%, a solvent content of 30%, a density of 1.19 kg / l, a flow rate of 9.238 t / h, and a top aqueous phase of 71.193 t / h, of which the solvent content is 73.1%, water content is 26.8%, and the density is 1.04 kg / l.

[0046] The material balance table of the above embodiment is as follows:

[0047] Material balance

[0048]

[0049]

[0050] Note: The solvent NMP includes a catalyst solvent and a polymerization solvent.

[0051] According to the different brands, the proportions are adjusted and the five PK brands are as follows:

[0052] Product brand and polymerization ratio correspondence table

[0053] Product Brand HF-PK1 HF-PK2 HF-PK3 HF-PK4 HF-PK5 Carbon monoxide % (mol) 100 100 100 100 100 Ethylene content % (mol) 94 89 77 63 56 Propylene content % (mol) 6 11 23 37 46 Solvent: Polymer 8：2 8：2 8：2 8：2 8：2

[0054] Product Mechanical Properties Table

[0055]

Claims

1. A PK polymerization system, characterized in that: The invention comprises a polymerization kettle (1), an extraction kettle (2) and an extraction tower (3), wherein the polymerization kettle (1) and the extraction kettle (2) are both provided with a heat exchange interlayer and a stirrer. The top of the polymerization kettle (1) is provided with a raw material inlet (11), a catalyst inlet (12), and a first vapor phase outlet (13); the raw material inlet (11) is connected to an ethylene source, a propylene source, a carbon monoxide source, and an N-methylpyrrolidone source through a microinterface reactor (4); the catalyst inlet (12) is connected to the catalyst source; the first vapor phase outlet (13) is connected to a first gas-liquid separator (5); and the discharge port at the bottom of the polymerization kettle (1) supplies materials to the extraction kettle (2). The top of the extraction kettle (2) is provided with a desalted water inlet (21) and a second vapor phase outlet (22), the desalted water inlet (21) is connected to a desalted water source, the second vapor phase outlet (22) is connected to a second gas-liquid separator (6), and the bottom discharge port of the extraction kettle (2) supplies materials to the extraction tower (3). The gas phase outlets of the first gas-liquid separator (5) and the second gas-liquid separator (6) are refluxed to the polymerization kettle (1) through the recovery compressor (7) and the cooler (8), and the liquid phase outlets are refluxed to the polymerization kettle (1) and the extraction kettle (2), respectively. The extraction tower (3) has a bottom discharge port for discharging the PK polymer to the outside.

2. The PK aggregation system according to claim 1, characterized in that: The tops of the extraction kettle (2) and the extraction tower (3) are both provided with inert gas regulating valves for discharging inert purge gas to the outside.

3. The PK aggregation system according to claim 1, characterized in that: The extraction tower (3) is provided with a plurality of first heat exchange plates (31) and second heat exchange plates (32) at intervals along the height direction, each heat exchange plate is provided with a heat exchange cavity, the cross section of the first heat exchange plate (31) is hook-shaped, the cross section of the second heat exchange plate (32) is figure eight-shaped, the projections of the two extended ends of the first heat exchange plate are located on the adjacent second heat exchange plate, and the two extended ends of the second heat exchange plate are located on the adjacent first heat exchange plate.

4. The PK aggregation system according to claim 1, characterized in that: The feed port of the extraction tower (3) is located in the middle of the side wall, and the upper side wall of the extraction tower (3) is provided with a solvent recovery port for discharging the solvent to the outside.

5. A process for synthesizing PK using any polymerization system according to any one of claims 1 to 4, characterized in that: The following steps are involved: 1) Ethylene, propylene, carbon monoxide and N-methylpyrrolidone are mixed in a microinterface reactor and then fed into a polymerization kettle, and a catalyst is fed into a polymerization kettle; 2) Control the temperature to 80°C, the pressure to 4.0MPa(G), and the polymerization time to 0.9-1h to complete the polymerization reaction; 3) The temperature in the extraction kettle is controlled to be 80°C and the pressure is controlled to be 3.0MPa(G), and the mixed material that has completed the polymerization reaction in the polymerization kettle is sent into the extraction kettle under the action of differential pressure; 4) Desalted water is sent into the extraction kettle to terminate the polymerization reaction; 5) The mixture after the polymerization reaction is terminated in the extraction kettle is sent to the middle part of the extraction tower. The hook-shaped plates and the figure-eight plates are arranged alternately in the extraction tower. Hot water at 85°C flows in the cavity of the plates. The temperature of the extraction tower is controlled at 80°C±2 by controlling the flow rate of hot water. A solvent-water mixture is obtained at the top of the tower, and a polymer-solvent mixture is obtained at the bottom of the tower.

6. The process according to claim 5, characterized in that Step 1) the molar ratio of carbon monoxide to the sum of ethylene and propylene is 1:1, the molar ratio of ethylene to propylene is 56-94:6-46, preferably 9:1, the mass ratio of N-methylpyrrolidone to the sum of ethylene, propylene and carbon monoxide is 8:2, the catalyst is an anionic organic metal complex formed by palladium acetate as the main catalyst, 4,6-dihydroxy-2-methylpyrimidine as the ligand, maleic acid as the anionic co-catalyst, and N-methylpyrrolidone as the catalyst solvent, and the added amount is 22.63% of the sum of the mass of carbon monoxide, ethylene and propylene.

7. The process according to claim 6, characterized in that Step 1) The catalyst preparation method is: a) dissolving palladium acetate, 4,6-dihydroxy-2-methylpyrimidine and maleic acid respectively with N-methylpyrrolidone; b) controlling the temperature to 80-90° C., mixing and stirring the palladium acetate solution and the 4,6-dihydroxy-2-methylpyrimidine solution for 3 hours, wherein the molar ratio of palladium acetate to 4,6-dihydroxy-2-methylpyrimidine is 1:1.5-3; c) adding maleic acid solution, stirring and reacting for 2 hours to obtain a mixture containing a catalyst, wherein the molar ratio of palladium acetate to maleic acid is 1:3-21.

8. The process according to claim 5, characterized in that The molar ratio of the desalted water and N-methylpyrrolidone added in step 4) is 2:1.

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