Device and method for preparing high-performance polyolefin key monomer

Abstract

The invention relates to the technical field of chemical processes, and particularly provides a device and a method for preparing a high-performance polyolefin key monomer. The detachable tubular reactor is applied to the production process of preparing NB through the reaction of ethylene and DCPD / CPD, so that the production safety is improved; meanwhile, the advantages of mass and heat transfer and pressure resistance of the tubular reactor are utilized, so that high conversion rate and high selectivity of the reaction are ensured. In addition, the problem of raw material blockage can be solved by adopting each section of bypass and a detachable flange connection mode in the device for preparing the high-performance polyolefin key monomer.

Description

Technical Field

[0001] The present application relates to the field of chemical process technology, and in particular to providing a device and method for preparing a key monomer of a high-performance polyolefin, and specifically, providing a device and method for preparing a key monomer of a high-performance polyolefin using a detachable tubular reactor. Background Art

[0002] Cyclic olefin copolymer (COC) is a copolymer of cyclic olefin and ethylene or α-olefin. Among them, NB-based cyclic olefin copolymer obtained by copolymerization of norbornene monomer (NB) and ethylene monomer is the most widely used product in the market. It has optical properties comparable to polymethyl methacrylate (PMMA) and heat resistance higher than polycarbonate (PC), and has better dimensional stability than PMMA and PC. In addition, NB-based cyclic olefin copolymer also has excellent water vapor barrier, chemical resistance and safety, so it is widely used in medical, packaging, electronic components and optical materials with strict quality standards. It is a new type of high-performance polyolefin with broad development prospects.

[0003] Norbornene monomer (NB) is a key monomer and is prepared by Diels-Alder reaction of dicyclopentadiene (DCPD) or cyclopentadiene (CPD) with ethylene under high temperature and high pressure (Formula I).

[0004]

[0005] In addition, the above reaction process is accompanied by side reactions. In a paper published in the Journal of the Japan Petroleum Institute, Tsuchiya Shozo proposed that DCPD will undergo thermal polymerization at 250℃-270℃ to produce a resin containing a large number of double bonds, and the molecular weight increases with the reaction time. This resin is often difficult to dissolve in solvents and remains in the reactor in the form of precipitation, causing scaling and clogging of the reactor, seriously affecting the safety of the reaction.

[0006] According to the different phases of CPD or DCPD in the reactor, the production processes of norbornene monomer (NB) are commonly gas phase reaction process and liquid phase reaction process. Among them, although the materials in the gas phase reaction process can be fully mixed, the molar volume of the gas phase material is greatly increased. In the reactor of the same volume, the residence time is significantly shorter than that of the liquid phase process, and the DCPD conversion rate is relatively low and the output is low. In addition, the temperature of the gas phase reaction process is about 100°C higher than that of the liquid phase reaction process, which will cause more engineering safety problems. The solvent-free liquid phase reaction process has serious side reactions and is prone to produce multimers or polymers (CPD and DCPD undergo Diels-Alder reaction to generate low molecular weight oligomers, and the oligomers are further polymerized to generate comb-shaped polymer resins), causing blockage of the reactor and related equipment. After adding an inert solvent, the generation of multimers or polymers can be inhibited to a certain extent and the selectivity of the reaction can be improved.

[0007] Since the reaction of ethylene with DCPD or CPD to synthesize norbornene monomer (NB) is a high-temperature, high-pressure and heterogeneous reaction system, how to solve the mass transfer and heat transfer problems in the reaction process and meet the demanding reaction conditions is a major problem in the industrial production of norbornene monomer (NB). Chinese patent CN102249839A proposes to apply the loop reactor to the synthesis of norbornene monomer (NB), giving full play to its advantages of fast mass transfer and heat transfer and pressure resistance, and improving the safety of the reaction process. Although the process has been verified at the laboratory level, there are still many engineering problems that have not been solved, such as reactor blockage, reaction temperature control, and material recovery. Summary of the invention

[0008] The purpose of the present application is to overcome the above-mentioned deficiencies of the prior art and to provide a device and method for preparing high-performance polyolefin key monomers using a detachable tubular reactor.

[0009] To achieve the above purpose, the technical solution adopted by this application is:

[0010] The present application provides a device for preparing a key monomer of high-performance polyolefin, comprising a liquid raw material tank / ethylene buffer tank, a detachable reactor heating section, a detachable reactor cooling section, a flash tank, a heat exchanger, a gas-liquid separation tank and an ethylene recovery compressor connected in sequence; the ethylene recovery compressor is connected to the ethylene buffer tank;

[0011] The detachable reactor heating section and the detachable reactor cooling section are provided with bypasses;

[0012] The device is also provided with a flushing solvent tank containing an inert solvent, and the flushing solvent tank is connected to a detachable reactor heating section.

[0013] The device for preparing high-performance polyolefin key monomers in the present application includes a liquid raw material tank / ethylene buffer tank, a detachable reactor heating section, a detachable reactor cooling section, a flash tank, a heat exchanger, a gas-liquid separation tank and an ethylene recovery compressor, which solves the problem of easy clogging of the reactor and has the advantages of controlling reaction temperature and material recovery.

[0014] Among them, insoluble impurity precipitation will be produced during the synthesis reaction of norbornene monomer (NB). As the operation time of the device increases, the precipitation will scale and clog, bringing great safety risks to the operating device. The present application adopts a detachable reactor heating section and a detachable reactor cooling section, and a bypass is provided in the detachable reactor heating section and the detachable reactor cooling section. When there is a risk of blockage in the operating device, the bypass can be switched in time to avoid danger. At the same time, the stable operation of the device can be maintained, the risk caused by the reactor pressure is reduced, and the safety of the reaction is improved. For a blocked section of the reactor, it can be removed and cleaned.

[0015] The device for preparing key monomers of high-performance polyolefins in the present application is also provided with a flushing solvent tank. When the reactor stops reacting and the liquid raw material tank stops feeding, the flushing solvent is fed into the flushing solvent tank separately to circulate and flush the reactor and its bypass, so as to flush out impurities in the reactor, wash away insoluble impurities and scaling, reduce the occurrence of blockage problems, and extend the service life of the reactor (the usable time before the reactor is blocked).

[0016] Furthermore, the device of the present application is also provided with an ethylene recovery compressor, the presence of which can improve the utilization rate of ethylene and reduce costs.

[0017] In some specific embodiments, a filter and a liquid phase delivery pump are sequentially arranged on the discharge pipeline of the flushing solvent tank.

[0018] A liquid phase delivery pump is used to separately introduce flushing solvent to circulate and flush the reactor to wash away insoluble impurities and scaling. The solvent can be recycled and the impurities are eventually intercepted on the filter.

[0019] In some specific embodiments, a discharge port is provided at the bottom of the liquid raw material tank; the liquid raw material tank is used to contain the liquid raw material dicyclopentadiene and / or cyclopentadiene, or a solution of the liquid raw material dicyclopentadiene and / or cyclopentadiene in an inert solvent.

[0020] In some specific embodiments, the flushing solvent tank is used to contain an inert solvent (the inert solvent includes at least one of straight-chain aliphatic hydrocarbons, cyclic aliphatic hydrocarbons and aromatic hydrocarbons; preferably, the inert solvent is toluene or cyclohexane), and the flushing solvent tank is provided with a fresh solvent feed port, a waste liquid discharge port and a discharge port to the heating section of the reactor.

[0021] As a preferred embodiment of the device for preparing high-performance polyolefin key monomers described in the present application, there are multiple ethylene buffer tanks, and ethylene compressors are arranged between the ethylene buffer tanks.

[0022] In some specific embodiments, there are three ethylene buffer tanks, which are divided into ethylene buffer tank I, ethylene buffer tank II and ethylene buffer tank III; there are two ethylene compressors, which are divided into ethylene compressor I and ethylene compressor II.

[0023] The ethylene buffer tank I is used to stabilize the suction pressure of the ethylene compressor I; the ethylene buffer tank I is provided with a fresh ethylene feed port, a recycled ethylene injection port and a discharge port to the ethylene compressor I.

[0024] The ethylene buffer tank II is used to stabilize the suction pressure of the ethylene compressor II; the ethylene buffer tank II is provided with an ethylene feed port and a discharge port to the ethylene compressor II.

[0025] The ethylene buffer tank III is used to stabilize the feed pressure of the reactor; the ethylene buffer tank III is provided with an ethylene feed port and a discharge port to the reactor, and can be injected into the reactor heating section at multiple locations, and a one-way valve and a three-way valve are provided on the discharge pipeline.

[0026] The inlet and outlet of the ethylene compressor I and the ethylene compressor II are both provided with check valves; the ethylene compressor I and the ethylene compressor II are used for ethylene pressurization.

[0027] As a preferred embodiment of the device for preparing high-performance polyolefin key monomers described in the present application, the reactor heating section includes a plurality of segmented tube reactors connected in series via detachable flanges, and the reactor heating section is used for heating and reacting raw materials.

[0028] As a preferred embodiment of the device for preparing high-performance polyolefin key monomers described in the present application, the reactor cooling section includes a plurality of segmented tube reactors connected in series via detachable flanges, and the reactor cooling section is used for cooling the reaction product.

[0029] The tubular reactor used in the present application has the advantages of fast mass and heat transfer and pressure resistance, ensuring high conversion rate and high selectivity of the reaction and improving the safety of the reaction.

[0030] The tubular reactors in the reactor heating section and the reactor cooling section of the present application are connected by detachable flanges, which can solve the problem of reaction blockage; for example, by operating the valve, the inlet and outlet of the blocked section or multiple ends of the reactor are closed, and the raw materials flow through the bypass. The tubular reactor is connected by disassembling the flange, and the blocked reactor is removed for clearing.

[0031] In the present application, when the feeding of liquid raw materials and gaseous raw materials is stopped, a filter and a liquid delivery pump are sequentially arranged on the discharge pipeline of the flushing solvent tank, which passes through the heating section of the reactor and the cooling section of the reactor in sequence and enters the flash tank; the flushing solvent is returned to the flushing solvent tank by operating the valve at the bottom of the flash tank, thereby realizing the recycling of the solvent; the waste flushing solvent can be discharged through the drain valve at the bottom of the flushing solvent tank, and the flushing solvent tank can be supplemented with fresh flushing solvent to maintain the liquid level. The above operations can also solve the blockage problem of the reactor.

[0032] As a preferred embodiment of the device for preparing high-performance polyolefin key monomers described in the present application, the tubular reactor in the heating section of the reactor is provided with a bypass and a valve;

[0033] The tubular reactor in the reactor cooling section is provided with a bypass and a valve, and the tubular reactor at the end is provided with a pressure regulating valve.

[0034] In the present application, the bypass sections of the tubular reactor and the detachable flange connection method make it possible to switch to the bypass to maintain the operation of the device when a blockage problem occurs during the operation of the tubular reactor. The blocked section can be removed through the flange and cleared without having to stop the device first and then clear the blockage.

[0035] The temperature of each tubular reactor in the heating section of the reactor of the present application can be controlled independently or simultaneously, three-way valves are set for raw material feeds, ethylene can be injected into the heating section of the reactor simultaneously or independently through different injection ports, and a pressure regulating valve is set at the outlet of the cooling section of the reactor, so that the reaction conditions such as the reaction temperature of the heating section of the reactor, the material flow rate of the reaction, the feed position of ethylene, the pressure of the entire reactor, etc. can be freely adjusted, and the operation flexibility is large.

[0036] As a preferred embodiment of the device for preparing high-performance polyolefin key monomers described in the present application, both the reactor heating section and the reactor cooling section are provided with static mixers.

[0037] In some specific embodiments, the tubular reactors of the reactor heating section and the reactor cooling section have a length of 2 meters and an inner diameter of 2 centimeters.

[0038] The tubular reactor of the present application is designed to be divided into several sections of relatively short length, which is convenient for clearing blockages after disassembly. The tubular reactor can also be circulated and flushed using a flushing solvent tank to flush out impurities in the tubular reactor.

[0039] The reactor heating section and reactor cooling section of the present application can be heated or cooled by water, electricity, steam, oil, etc., and each section of the reactor can be temperature controlled independently or simultaneously.

[0040] In some specific embodiments, a demister is provided in the flash tank, and a NB product liquid discharge pipeline is provided at the bottom for discharging the NB product liquid after flash evaporation.

[0041] In some specific embodiments, the heat exchanger is a high-efficiency heat exchanger for condensing impurities in the ethylene, and the condensate can be refluxed back to the flash tank.

[0042] The gas-liquid separation tank is used for gas-liquid separation before the ethylene compressor and to stabilize the suction pressure of the ethylene compressor.

[0043] The ethylene recovery compressor is used for ethylene booster recovery, and the recovered ethylene is sent to the ethylene buffer tank I; the inlet and outlet of the ethylene recovery compressor are provided with check valves.

[0044] Each regulating valve provided in the present application can automatically adjust the valve opening according to the corresponding process parameters.

[0045] The present application also provides a method for preparing a key monomer for high-performance polyolefins, based on the device for preparing a key monomer for high-performance polyolefins, comprising the following steps:

[0046] 1)1) injecting the liquid raw material dicyclopentadiene and / or cyclopentadiene, or a solution of the liquid raw material dicyclopentadiene and / or cyclopentadiene in an inert solvent, into the heating section of the reactor, and adjusting the feed flow rate of the liquid raw material;

[0047] 2) The gaseous raw material ethylene is pressurized by an ethylene compressor and then injected into the heating section of the reactor to adjust the feed flow rate of the gaseous raw material;

[0048] 3) uniformly mixing the liquid raw material and the gas raw material in the heating section of the reactor to obtain a reaction liquid, injecting the reaction liquid into the cooling section of the reactor for cooling, and adjusting the pressure of the heating section of the reactor and the cooling section of the reactor to obtain a pressurized reaction liquid;

[0049] 4) injecting the pressurized reaction liquid into a flash tank for further flash evaporation to obtain flash-evaporated recovered ethylene and norbornene monomer solution; the flash-evaporated recovered ethylene is condensed and impurity-removed by a heat exchanger and then injected into a gas-liquid separation tank; then the treated ethylene is pressurized by an ethylene recovery compressor and injected into an ethylene buffer tank, mixed with fresh ethylene, and recycled.

[0050] In some specific embodiments, the liquid-phase delivery pump is a liquid-phase delivery pump with a filter.

[0051] The pressure in the heating section and cooling section of the reactor is regulated by a pressure regulating valve.

[0052] In the technical solution of the present application, the liquid raw materials of dicyclopentadiene and / or cyclopentadiene, or a solution of the liquid raw materials of dicyclopentadiene and / or cyclopentadiene prepared in an inert solvent, are introduced into the first reactor of the heating section of the reactor through a liquid delivery pump with a filter, and the three-way valve at the outlet of the liquid delivery pump can control the liquid feed flow rate.

[0053] In addition, the gaseous raw material fresh ethylene is pressurized step by step by ethylene compressor I and ethylene compressor II, and then injected into the heating section of the reactor simultaneously or independently at different injection ports, and the gaseous feed flow rate is controlled by a three-way valve; the liquid raw material and the gas raw material are evenly mixed in the heating section of the reactor by means of a static mixer, and are heated to the reaction temperature to complete the reaction and obtain a reaction liquid; the reaction liquid enters the cooling section of the reactor from the heating section of the reactor to be cooled and the reaction is terminated, and the pressure of the heating section and the cooling section of the reactor are controlled by a pressure regulating valve at the reactor outlet to obtain a pressurized reaction liquid; the pressurized reaction liquid flows out of the pressure regulating valve and enters the flash tank for flash evaporation, and the flash evaporation pressure is controlled by the pressure regulating valve after the heat exchanger; the recovered ethylene obtained by flash evaporation enters the gas-liquid separation tank after condensation and impurity removal in the heat exchanger, and then is pressurized by the ethylene recovery compressor and passed into the ethylene buffer tank I for mixing with fresh ethylene for recycling; the NB product liquid after flash evaporation is discharged through the bottom drain valve.

[0054] As a preferred embodiment of the method for preparing a key monomer for high-performance polyolefins described in the present application, the molar ratio of the gas phase raw material to the liquid phase raw material is (1-10):1.

[0055] The molar ratio of the gas phase raw material to the liquid phase raw material is adopted to promote the full reaction of dicyclopentadiene and cyclopentadiene and improve the conversion rate of the product.

[0056] As a preferred embodiment of the method for preparing a high-performance polyolefin key monomer described in the present application, the inert solvent includes at least one of a linear aliphatic hydrocarbon, a cyclic aliphatic hydrocarbon and an aromatic hydrocarbon. Preferably, the inert solvent is toluene or cyclohexane.

[0057] As a preferred embodiment of the method for preparing a high-performance polyolefin key monomer described in the present application, the temperature of the tubular reactor in the reactor heating section is 170 to 270°C;

[0058] The absolute pressure of the tubular reactor in the reactor heating section and the reactor cooling section is 5 to 30 MPa.

[0059] The temperature of the outlet of the tubular reactor in the reactor cooling section is 20-100°C.

[0060] By adopting the above reaction conditions, the ethylene in the reaction system can be placed in a supercritical state.

[0061] The reaction conditions such as temperature, flow rate, feed position, pressure, etc. of the device used in the present application can be freely adjusted, and the operation flexibility is large, which can meet the needs of different operating conditions.

[0062] Compared with the prior art, this application has the following beneficial effects:

[0063] The present application provides a device and method for preparing a high-performance polyolefin key monomer. The present application adopts a detachable tubular reactor for the production process of preparing NB by reacting ethylene with DCPD / CPD to improve the safety of production; at the same time, the advantages of mass transfer, heat transfer and pressure resistance of the tubular reactor are utilized to ensure high conversion rate and high selectivity of the reaction. In addition, the bypass of each section and the detachable flange connection method in the device for preparing a high-performance polyolefin key monomer of the present application can solve the problem of raw material blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 A flow chart of an apparatus for preparing key monomers of high-performance polyolefins for the present application (wherein, 1: liquid raw material tank; 2: flushing solvent tank; 3: ethylene buffer tank I; 4: ethylene buffer tank II; 5: ethylene buffer tank III; 6: ethylene compressor I; 7: ethylene compressor II; 8: reactor heating section; 9: reactor cooling section; 10: flash tank; 11: heat exchanger; 12: gas-liquid separation tank; 13: ethylene recovery compressor). DETAILED DESCRIPTION

[0065] In order to better illustrate the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0066] In the following examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified, and the components and raw materials used in each parallel experiment are of the same type.

[0067] Example 1: A device for preparing key monomers of high-performance polyolefins

[0068] like Figure 1 As shown, the embodiment of the present application provides a device for preparing a key monomer of high-performance polyolefin, comprising a liquid raw material tank / ethylene buffer tank, a detachable reactor heating section, a detachable reactor cooling section, a flash tank, a heat exchanger, a gas-liquid separation tank and an ethylene recovery compressor connected in sequence; the ethylene recovery compressor is connected to the ethylene buffer tank;

[0069] The device is also provided with a flushing solvent tank, which is connected to a detachable reactor heating section;

[0070] The detachable reactor heating section and the detachable reactor cooling section are provided with bypasses.

[0071] There are multiple ethylene buffer tanks, and ethylene compressors are arranged between the ethylene buffer tanks; the ethylene buffer tanks are divided into ethylene buffer tank I, ethylene buffer tank II and ethylene buffer tank III; there are two ethylene compressors, which are ethylene compressor I and ethylene compressor II. Ethylene buffer tank I is connected to ethylene compressor I, ethylene compressor I is connected to ethylene buffer tank II, ethylene buffer tank II is connected to ethylene compressor II, ethylene compressor II is connected to ethylene buffer tank III, and ethylene buffer tank III is connected to a detachable reactor heating section.

[0072] The ethylene buffer tank I is provided with a fresh ethylene feed port, a recovered ethylene injection port and a discharge port to the ethylene compressor I; similarly, the ethylene buffer tank II is provided with a recovered ethylene injection port and a discharge port to the ethylene compressor II; the ethylene buffer tank III is provided with a recovered ethylene injection port and a discharge port to the detachable reactor heating section.

[0073] Among them, the liquid raw material tank is connected to a liquid phase delivery pump I with a filter, and the liquid phase delivery pump I with a filter is connected to a detachable reactor heating section; the flushing solvent tank is connected to a liquid phase delivery pump II with a filter, and the liquid phase delivery pump II with a filter is connected to a detachable reactor heating section; the liquid phase delivery pump I is connected to the liquid phase delivery pump II; and a liquid feed port and a waste liquid discharge port are provided at the bottom of the flushing solvent tank.

[0074] The reactor heating section comprises a plurality of tubular reactors connected in series via detachable flanges, and the reactor heating section contains 15 tubular reactors; the reactor heating section is used for heating and reacting raw materials.

[0075] The reactor cooling section comprises a plurality of tubular reactors connected in series via detachable flanges, and the reactor cooling section contains 5 tubular reactors; the reactor cooling section is used for cooling the reaction products.

[0076] The tubular reactor in the reactor heating section is provided with a bypass and a three-way valve;

[0077] The tubular reactor in the cooling section of the reactor is provided with a bypass and a three-way valve, and the tubular reactor at the end is provided with a pressure regulating valve.

[0078] Each section of the reactor in the reactor heating section and the reactor cooling section has a length of 2 meters and an inner diameter of 2 centimeters. The reactor heating section and the reactor cooling section are both provided with static mixers.

[0079] The flash tank is provided with an inlet for the reaction liquid and an outlet for the norbornene monomer solution; the outlet of the heat exchanger is provided with a pressure regulating valve; and the gas-liquid separation tank is provided with an inlet for recovering ethylene and an outlet for the waste liquid.

[0080] Example 2: A method for preparing a key monomer for high-performance polyolefins

[0081] This embodiment provides a method for preparing a high-performance polyolefin key monomer, based on the device for preparing a high-performance polyolefin key monomer of Example 1, comprising the following steps:

[0082] 1) Inject the liquid raw material of the DCPD toluene solution with a concentration of 20wt% in the liquid raw material tank into the heating section of the reactor (the first section reactor), and adjust the feed flow rate of the liquid raw material by a three-way valve (the flow rate of the DCPD toluene solution is 50kg / h);

[0083] 2) The gaseous raw material ethylene is pressurized by an ethylene compressor and then injected into the heating section of the reactor (the first section of the reactor). The feed flow rate of the gaseous raw material is adjusted by a three-way valve (the flow rate of ethylene is 10.6 kg / h);

[0084] 3) The liquid raw material and the gas raw material in the heating section of the reactor are mixed and heated uniformly (fully mixed by the static mixer in the reactor), the temperature of the tubular reactor in the heating section of the reactor is 250° C., and a reaction liquid is obtained. The reaction liquid is injected into the cooling section of the reactor for cooling. The temperature of the terminal tubular reactor in the cooling section of the reactor is 70° C. The pressure of the heating section of the reactor and the cooling section of the reactor is adjusted (the absolute pressure is 24 MPa) to obtain a pressurized reaction liquid;

[0085] 4) injecting the pressurized reaction liquid into a flash tank for further flash evaporation to obtain flash-evaporated recovered ethylene and norbornene monomer solution; the flash-evaporated recovered ethylene is condensed and impurity-removed by a heat exchanger and then injected into a gas-liquid separation tank; then the treated ethylene is pressurized by an ethylene recovery compressor and injected into an ethylene buffer tank, mixed with fresh ethylene, and recycled.

[0086] The molar ratio of the gas phase raw material (ethylene) to the liquid phase raw material (dicyclopentadiene) is 5:1.

[0087] The flow rate of the product liquid discharged from the bottom of the flash tank is 53.7 kg / h, of which the content of norbornene monomer (NB) is 22.3 wt%, the conversion rate of dicyclopentadiene (DCPD) is 94.2%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 89%.

[0088] Example 3: A method for preparing a key monomer for high-performance polyolefins

[0089] Compared with Example 2, the difference of Example 3 is that the flow rate of ethylene is 21.2 kg / h, the molar ratio of the gas phase raw material (ethylene) to the liquid phase raw material (dicyclopentadiene) is 10:1, and the rest of the preparation method is the same as Example 2.

[0090] The flow rate of the product liquid discharged from the bottom of the flash tank is 53.9 kg / h, of which the NB content is 23.1 wt%, the conversion rate of DCPD is 96.1%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 90.9%.

[0091] Example 4: A method for preparing a key monomer for high-performance polyolefins

[0092] Compared with Example 2, the difference of Example 4 is that the temperature of the tubular reactor in the reactor heating section is 180° C., and the rest of the preparation method is the same as that of Example 2.

[0093] The flow rate of the product liquid discharged from the bottom of the flash tank is 52.6 kg / h, of which the NB content is 16.3 wt%, the conversion rate of DCPD is 79.8%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 75.2%.

[0094] Example 5: A method for preparing a key monomer for high-performance polyolefins

[0095] Compared with Example 2, the difference of Example 5 is: the pressure of the reactor heating section and the reactor cooling section (absolute pressure is 5 MPa), and the rest of the preparation method is the same as Example 2.

[0096] The flow rate of the product liquid discharged from the bottom of the flash tank is 51.1 kg / h, in which the NB content is 4.7 wt %, the conversion rate of DCPD is 62.1%, and the selectivity is 30.4%.

[0097] Example 6: A method for preparing a key monomer for high-performance polyolefins

[0098] Compared with Example 2, the difference of Example 6 is that: in step 2), the gaseous raw material ethylene is pressurized by an ethylene compressor and then injected into the heating section of the reactor (the fourth section inlet of the heating section of the reactor), and the feed flow rate of the gaseous raw material is adjusted by a three-way valve (the flow rate of ethylene is 10.6 kg / h). The rest of the preparation method is the same as that of Example 2.

[0099] The flow rate of the product liquid discharged from the bottom of the flash tank is 53.8 kg / h, of which the NB content is 22.5 wt%, the conversion rate of DCPD is 92.6%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 91.5%.

[0100] Example 7: A method for preparing a key monomer for high-performance polyolefins

[0101] Compared with Example 2, the difference of Example 7 is that the molar ratio of the gas phase raw material (ethylene) to the liquid phase raw material (dicyclopentadiene) is 1:1, and the rest of the preparation method is the same as Example 2.

[0102] Additional results:

[0103] The flow rate of the product liquid discharged from the bottom of the flash tank is 51.3 kg / h, of which the NB content is 7.8 wt %, the conversion rate of DCPD is 74.3%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 37.8%.

[0104] Example 8: A method for preparing a key monomer for high-performance polyolefins

[0105] Compared with Example 2, the difference of Example 8 is: the pressure of the reactor heating section and the reactor cooling section (absolute pressure is 30 MPa), and the rest of the preparation method is the same as Example 2.

[0106] The flow rate of the product liquid discharged from the bottom of the flash tank is 54.0 kg / h, of which the content of norbornene monomer (NB) is 22.6 wt%, the conversion rate of dicyclopentadiene (DCPD) is 94.7%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 90.1%.

[0107] Example 9: A method for preparing a key monomer for high-performance polyolefins

[0108] Compared with Example 2, the difference of Example 9 is that the reactor heating section is composed of 20 tubular reactors, and the rest of the preparation method is the same as that of Example 2.

[0109] The flow rate of the product liquid discharged from the bottom of the flash tank is 53.7 kg / h, of which the content of norbornene monomer (NB) is 22.2 wt%, the conversion rate of dicyclopentadiene (DCPD) is 96.5%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 86.7%.

[0110] Comparative Example 1

[0111] Compared with Example 2, the difference of Comparative Example 1 is that the liquid raw material is replaced with pure dicyclopentadiene, which is directly injected into the heating section of the reactor (the first reactor), and the rest of the preparation method is the same as that of Example 2.

[0112] The flow rate of the product liquid discharged from the bottom of the flash tank is 53.2 kg / h, of which the content of norbornene monomer (NB) is 19.5 wt%, the conversion rate of dicyclopentadiene (DCPD) is 47.2%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 29.8%.

[0113] After 12 hours of reaction, obvious impurity precipitation appeared on the inner surface of the pipelines in the heating section and cooling section of the reactor and on the surface of the static mixer.

[0114] Comparative Example 2

[0115] Compared with Example 2, the difference of Comparative Example 2 is that the tubular reactor of the device for preparing high-performance polyolefin key monomers is not equipped with a bypass and a three-way valve between each segment of the tubular reactor, and each segment of the tubular reactor is directly connected in the form of a flange through a straight pipe section, and the rest of the preparation method is the same as Example 2.

[0116] The flow rate of the product liquid discharged from the bottom of the flash tank is 53.5 kg / h, of which the content of norbornene monomer (NB) is 22.1 wt%, the conversion rate of dicyclopentadiene (DCPD) is 93.8%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 87.9%.

[0117] When the cumulative operating time of the reactor reached 300 hours, the conversion rate and selectivity of dicyclopentadiene dropped to 90.1% and 85.2% respectively, and obvious impurity precipitation appeared on the inner surface of the pipes in the heating and cooling sections of the reactor and on the surface of the static mixer (in the absence of a bypass, the precipitation in the reactor will continue to accumulate, and when the cumulative operating time is long enough, the precipitation will block the reaction section).

[0118] Comparative Example 3

[0119] Compared with Example 2, the difference of Comparative Example 3 is that the temperature of the tubular reactor in the reactor heating section is 300° C., and the rest of the preparation method is the same as that of Example 2.

[0120] The flow rate of the product liquid discharged from the bottom of the flash tank is 52.9 kg / h, of which the content of norbornene monomer (NB) is 17.4 wt%, the conversion rate of dicyclopentadiene (DCPD) is 96.4%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 65.2%. When the temperature is too high, the side reaction is intensified, and more oligomers and polymer resins are generated. Insoluble impurities are observed to be discharged at the outlet of the cooling section reactor, and obvious impurity precipitation appears on the inner surface of the pipeline in the heating section and cooling section of the reactor and on the surface of the static mixer.

[0121] Comparative Example 4

[0122] Compared with Example 2, the difference of Comparative Example 4 is: the pressure of the reactor heating section and the reactor cooling section (absolute pressure is 1 MPa), and the rest of the preparation method is the same as Example 2.

[0123] The flow rate of the product liquid discharged from the bottom of the flash tank is 50.9 kg / h, of which the content of norbornene monomer (NB) is 4.5 wt%, the conversion rate of dicyclopentadiene (DCPD) is 58.9%, and the NB selectivity (0.5 times the molar flow rate of NB in ​​the product divided by the molar flow rate of converted DCPD in the raw material) is 28.4%.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

Claims

1. A device for preparing a key monomer of high-performance polyolefin, characterized in that: It comprises a liquid raw material tank / ethylene buffer tank, a detachable reactor heating section, a detachable reactor cooling section, a flash tank, a heat exchanger, a gas-liquid separation tank and an ethylene recovery compressor which are connected in sequence; the ethylene recovery compressor is connected to the ethylene buffer tank; The detachable reactor heating section and the detachable reactor cooling section are provided with bypasses; The device is also provided with a flushing solvent tank containing an inert solvent, and the flushing solvent tank is connected to a detachable reactor heating section.

2. The device for preparing a key monomer for high-performance polyolefins according to claim 1, characterized in that: There are multiple ethylene buffer tanks, and ethylene compressors are arranged between the ethylene buffer tanks.

3. The device for preparing a key monomer for high-performance polyolefin according to claim 1, characterized in that: The reactor heating section comprises a plurality of segmented tube reactors connected in series via detachable flanges, and the reactor heating section is used for heating and reacting raw materials.

4. The device for preparing a key monomer for high-performance polyolefins according to claim 1, characterized in that: The reactor cooling section comprises a plurality of segmented tube reactors connected in series via detachable flanges, and the reactor cooling section is used for cooling the reaction product.

5. The device for preparing a key monomer for high-performance polyolefin according to claim 3 or 4, characterized in that: The tubular reactor in the reactor heating section is provided with a bypass and a valve; The tubular reactor in the reactor cooling section is provided with a bypass and a valve, and the tubular reactor at the end is provided with a pressure regulating valve.

6. The device for preparing a key monomer for high-performance polyolefin according to claim 5, characterized in that: The reactor heating section and the reactor cooling section are both provided with static mixers.

7. A method for preparing a key monomer of a high-performance polyolefin, characterized in that: The device for preparing a key monomer for high-performance polyolefin according to any one of claims 1 to 6 comprises the following steps: 1) injecting the liquid raw material dicyclopentadiene and / or cyclopentadiene, or a solution of the liquid raw material dicyclopentadiene and / or cyclopentadiene in an inert solvent into the heating section of the reactor, and adjusting the feed flow rate of the liquid raw material; 2) The gaseous raw material ethylene is pressurized by an ethylene compressor and then injected into the heating section of the reactor to adjust the feed flow rate of the gaseous raw material; 3) uniformly mixing the liquid raw material and the gas raw material in the heating section of the reactor to obtain a reaction liquid, injecting the reaction liquid into the cooling section of the reactor for cooling, and adjusting the pressure of the heating section of the reactor and the cooling section of the reactor to obtain a pressurized reaction liquid; 4) injecting the pressurized reaction liquid into a flash tank for further flash evaporation to obtain flash-evaporated recovered ethylene and norbornene monomer solution; the flash-evaporated recovered ethylene is condensed and impurity-removed by a heat exchanger and then injected into a gas-liquid separation tank; then the treated ethylene is pressurized by an ethylene recovery compressor and injected into an ethylene buffer tank, mixed with fresh ethylene, and recycled.

8. The method for preparing a key monomer for high-performance polyolefin according to claim 7, characterized in that: The molar ratio of the gas phase raw material to the liquid phase raw material is (1-10):

1.

9. The method for preparing a key monomer for high-performance polyolefin according to claim 7, characterized in that: The inert solvent includes at least one of a linear aliphatic hydrocarbon, a cyclic aliphatic hydrocarbon and an aromatic hydrocarbon.

10. The method for preparing a key monomer for high-performance polyolefin according to claim 7, characterized in that: The temperature of the tubular reactor in the reactor heating section is 170-270°C; The absolute pressure of the tubular reactor in the reactor heating section and the reactor cooling section is 5 to 30 MPa.

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