Process and system for preparing a butyl rubber base solution for halogenation and use thereof

Abstract

The application relates to the technical field of butyl rubber, and discloses a method and system for preparing butyl rubber base glue liquid for halogenation and application thereof. The preparation method comprises the following steps: S1, butyl rubber slurry is contacted with a protective gas in countercurrent to perform concentration treatment, and concentrated slurry and diluent containing unreacted monomers are obtained; S2, the concentrated slurry is mixed with a solvent and a terminating agent to obtain butyl rubber solution containing the diluent and the unreacted monomers; and S3, the butyl rubber solution containing the diluent and the unreacted monomers is subjected to rectification treatment to obtain gas phase and butyl rubber glue liquid, and the butyl rubber glue liquid is cooled to obtain butyl rubber base glue liquid for halogenation. In the method, the butyl rubber slurry is directly subjected to concentration treatment, energy consumed in the processes of temperature rising vaporization, separation and recondensation cooling is saved, and energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of butyl rubber, in particular, to a method and system for preparing butyl rubber base glue solution for halogenation and application thereof. BACKGROUND

[0002] The production process of halogenated butyl rubber mainly includes four parts: (1) production of base rubber; (2) preparation of glue solution; (3) halogenation reaction of glue solution; (4) product coagulation and drying. The production of base rubber generally adopts low-temperature slurry polymerization process with methyl chloride as diluent.

[0003] For the preparation process of glue solution, the low-temperature slurry hot water coagulation and resol process is generally adopted at present, that is, the butyl rubber low-temperature slurry overflowing from the polymerization kettle is first contacted with hot alkaline water introduced through the sleeve pipe when entering the degassing kettle to terminate the aluminum catalyst, and then water vapor introduced through the sleeve pipe is used to strip methyl chloride, while the rubber particles enter the water to form a rubber particle water slurry of about 5wt%. The rubber particle water slurry is then separated from water by a vibrating screen, dehydrated by a screw extruder, cut into particles and sent into hexane for dissolution. The obtained glue solution is then prepared into butyl rubber base glue solution for halogenation through dehydration process. This sol process not only has many processes and long route, but the most important problem is that methyl chloride is severely hydrolyzed by hot alkaline water, and the methyl chloride with high water content needs to be dried in a drying tower and remove hydrolysis impurities such as methanol and dimethyl ether before it can be recycled. Not only is the drying tower regenerated frequently, but the methyl chloride waste gas discharged from the drying tower needs to be treated by high-temperature incineration before it can be discharged.

[0004] CN111548436A discloses a preparation method of butyl rubber base glue solution for halogenation reaction. The method comprises the following steps: introducing butyl rubber slurry, solvent, terminator and diluent into a first mixer; then introducing into a second mixer for further mixing with butyl rubber solution to obtain butyl rubber solution after reaction termination; introducing the butyl rubber solution into a low-temperature dissolution tank for complete dissolution; introducing the obtained butyl rubber solution into a flash tank to preliminarily remove part of the diluent and unreacted monomers; introducing the butyl rubber solution after preliminary removal of part of the diluent and unreacted monomers into a dechloromethane tower to completely remove the diluent and unreacted monomers; and finally introducing into a glue solution concentration tower to concentrate to obtain butyl rubber base glue solution with appropriate concentration for preparing halogenated butyl rubber. This method not only has many processes and long route, but also the diluent in the butyl rubber slurry is recycled after being completely vaporized by heating, separated and then condensed and cooled, which has very high energy consumption. SUMMARY

[0005] The present application aims to overcome the problems of high energy consumption, multiple processes and long process flow in the prior art for preparing a butyl rubber base solution for halogenation, and provides a method and system for preparing a butyl rubber base solution for halogenation and application thereof. In the method, butyl rubber slurry is directly concentrated, thereby saving energy consumed in the processes of warming, vaporization, separation, recondensation and cooling, and reducing energy consumption. In particular, in the method for preparing the solution, the diluent is not in contact with water, and no impurities such as dimethyl ether are generated, thereby eliminating the process of chloromethane refining and reducing the number of processes and shortening the process flow, thereby significantly reducing the cost, and the butyl rubber base solution for halogenation prepared has a low catalyst content, thereby reducing the content of metal Al in the halogenated butyl product prepared from the base solution and improving the product quality.

[0006] To achieve the above-mentioned object, the present application provides a method for preparing a butyl rubber base solution for halogenation, characterized in that the method comprises the following steps:

[0007] S1. Butyl rubber slurry from a butyl rubber polymerization reaction is contacted with a protective gas in countercurrent to perform concentration treatment, to obtain concentrated slurry and diluent containing unreacted monomers;

[0008] S2. The concentrated slurry is mixed with a solvent and a terminating agent to obtain a butyl rubber solution containing diluent and unreacted monomers;

[0009] S3. The butyl rubber solution containing diluent and unreacted monomers is subjected to rectification treatment to obtain gas phase and butyl rubber solution, and the butyl rubber solution is cooled to obtain the butyl rubber base solution for halogenation.

[0010] The present application provides a system for preparing a butyl rubber base solution for halogenation, characterized in that the system comprises a reaction kettle 1, a concentration device 2, a sol gel kettle 3 and a rectification tower 4;

[0011] Butyl rubber slurry from the reaction kettle 1 is introduced into the concentration device 2 from the upper part of the concentration device 2, and is contacted with a protective gas from the bottom of the concentration device 2 in countercurrent to perform concentration treatment, to obtain concentrated slurry and diluent containing unreacted monomers, the concentrated slurry is discharged from the upper part of the concentration device 2, and the diluent containing unreacted monomers is discharged from the bottom of the concentration device 2;

[0012] The concentrated slurry is introduced into the sol gel kettle 3, and is mixed with a solvent and a terminating agent to obtain a butyl rubber solution containing diluent and unreacted monomers;

[0013] The butyl rubber solution containing diluent and unreacted monomers is introduced into the rectification tower 4 to perform rectification treatment, and the rectification tower obtains gas phase at the top and butyl rubber solution at the kettle;

[0014] cooling to obtain the halogenated butyl rubber base solution.

[0015] The third aspect of the present application provides a use of the above-mentioned method or system for preparing a halogenated butyl rubber base solution in the preparation of a halogenated butyl rubber base solution.

[0016] Through the above technical solution, the method and system for preparing a halogenated butyl rubber base solution and the use thereof provided by the present application have the following beneficial effects:

[0017] In the method for preparing a halogenated butyl rubber base solution provided by the present application, the butyl rubber slurry is directly concentrated, thereby saving the energy consumed in the processes of heating vaporization, separation and recondensation cooling, and reducing energy consumption. In particular, in the method for preparing the solution, the diluent does not contact water, and no impurities such as dimethyl ether are generated, thereby saving the process of chloromethane refining and the like, reducing the number of processes and shortening the process, and further significantly reducing the cost.

[0018] Further, the rectification treatment in the method includes rectification section treatment and stripping section treatment, and the butyl rubber solution containing the diluent and the unreacted monomer is sequentially separated, so that the unreacted monomer in the solution, the diluent, and the unreacted monomer are directly removed in one step, the process flow is simplified, and the cost is reduced.

[0019] Further, in the present application, part of the diluent containing the catalyst and the unreacted monomer is directly returned for the polymerization of butyl rubber, so that the content of the catalyst in the prepared halogenated butyl rubber base solution is low, the content of metal Al in the halogenated butyl product obtained after halogenation of the solution is low, and the product quality is good. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a flowchart of the method for preparing a halogenated butyl rubber base solution of the present application.

[0021] BRIEF DESCRIPTION OF DRAWINGS

[0022] 1, polymerization kettle; 2, concentration device; 3, solution kettle; 4, rectification column;

[0023] a-butyl rubber slurry; b-concentrated slurry; c-nitrogen; d-diluent containing unreacted monomer; e-terminating agent; f-solvent; g-butyl rubber solution containing diluent and unreacted monomer; h-liquid phase containing diluent and unreacted monomer substantially free of solvent; k-butyl rubber solution; m-halogenated butyl rubber base solution. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not considered critical for the purposes of the application. The endpoints of the ranges and any values are provided as approximations only and are understood to encompass a range of values which are near the recited values. For numerical ranges having endpoints, the endpoints are included in the range. For numerical ranges having endpoints, the endpoints are included in the range.

[0025] The first aspect of the present application provides a method for preparing a butyl rubber base solution for halogenation, characterized in that the method comprises the following steps:

[0026] S1, concentrating the butyl rubber slurry from the butyl rubber polymerization reaction by countercurrent contact with a protective gas to obtain a concentrated slurry and a diluent containing unreacted monomers;

[0027] S2, dissolving and mixing the concentrated slurry with a solvent and a terminator to obtain a butyl rubber solution containing a diluent and unreacted monomers;

[0028] S3, rectifying the butyl rubber solution containing a diluent and unreacted monomers to obtain a gas phase and a butyl rubber solution, and cooling the butyl rubber solution to obtain the butyl rubber base solution for halogenation.

[0029] In the present application, the method for preparing a butyl rubber base solution for halogenation directly concentrates the butyl rubber slurry, saving the energy consumed in the processes of heating vaporization, separation, and recondensation cooling, thereby reducing energy consumption. In particular, in the method for preparing the solution, the diluent does not contact water, and no impurities such as dimethyl ether are generated, thereby eliminating the process of chloromethane refining, reducing the number of processes and shortening the process, and significantly reducing the cost.

[0030] Further, by utilizing the difference in density between the butyl rubber particles and the diluent in the butyl rubber slurry, specifically, the density of the butyl rubber particles is smaller than that of the diluent, by controlling the countercurrent contact of the butyl rubber slurry with the protective gas, the butyl rubber particles in the butyl rubber slurry can be made to float, thereby realizing the separation of the butyl rubber and unreacted monomers and the diluent in the butyl rubber slurry and the concentration of the butyl rubber, to obtain a concentrated slurry containing nitrogen and a diluent containing unreacted monomers.

[0031] Further, in the present application, the terminator can complex with the catalyst in the concentrated slurry, thereby making the catalyst lose activity, and the butyl rubber particles in the concentrated slurry can be dissolved in the solvent to obtain the butyl rubber solution containing a diluent and unreacted monomers.

[0032] According to the present application, the content of the butyl rubber is 20-40 wt% based on the total weight of the butyl rubber slurry.

[0033] Further, the content of the butyl rubber is 25-35 wt% based on the total weight of the butyl rubber slurry.

[0034] According to the present application, the temperature of the butyl rubber slurry is -100°C to -88°C.

[0035] In the present application, when the temperature of the butyl rubber slurry is controlled to meet the above range, the butyl rubber slurry has the characteristics of low viscosity and excellent heat removal effect, and the halogenated butyl rubber prepared therefrom has high weight average molecular weight and excellent quality.

[0036] Further, the temperature of the butyl rubber slurry is -90°C to -98°C.

[0037] In the present application, the butyl rubber slurry is from a butyl rubber polymerization reaction, and preferably, the butyl rubber slurry is prepared by the following method:

[0038] The butyl rubber slurry is obtained by contacting isobutylene and isoprene in the presence of a diluent and a catalyst to perform a cationic polymerization reaction.

[0039] According to the present application, the temperature of the cationic polymerization reaction is -90°C to -98°C.

[0040] According to the present application, the diluent is selected from at least one of chloromethane, chloroethane and dichloromethane.

[0041] In the present application, the type of catalyst is not particularly limited, and a catalyst of a conventional type in the art can be used, for example, hydrogen chloride / dichloroethyl aluminum.

[0042] In the present application, the amount of isobutylene and isoprene is not particularly limited, and a conventional amount in the art can be used, for example, the amount of isobutylene and isoprene is such that the total concentration of isobutylene and isoprene in the polymerization system is 25-45 wt%. The relative amount of isobutylene and isoprene is not particularly limited, and can be appropriately selected according to the application of the final product, and generally, the content of isobutylene can be 90-98 wt% based on the total content of isobutylene and isoprene.

[0043] In one specific embodiment of the present application, the butyl rubber slurry is prepared by the following method:

[0044] (a) the monomer solution containing isobutylene, isoprene and diluent is separately cooled to -98°C by two stages of propylene and ethylene;

[0045] (b) the catalyst solution containing catalyst and diluent is separately cooled to -95°C by two stages of propylene and ethylene;

[0046] (c) in a reaction vessel, the cooled monomer solution and the cooled catalyst solution are contacted to perform a cationic polymerization reaction, to obtain the butyl rubber slurry. In the butyl rubber slurry, butyl rubber is suspended in the diluent in the form of microparticles.

[0047] According to the present application, the protective gas is selected from nitrogen and / or an inert gas, preferably nitrogen.

[0048] According to the present application, the temperature of the protective gas is -90℃ or lower.

[0049] In the present application, when the temperature of the protective gas is controlled to meet the above range, the temperature difference between the protective gas and the butyl rubber slurry is small, so that the temperature fluctuation of the butyl rubber slurry is small, and the butyl rubber microparticles in the butyl rubber slurry can be prevented from being bonded.

[0050] Further, the temperature of the protective gas is -92℃ to -98℃.

[0051] According to the present application, the mass flow ratio of the protective gas to the butyl rubber slurry is 1:100-300.

[0052] In the present application, when the mass flow ratio of the protective gas to the butyl rubber slurry is controlled to meet the above range, the butyl rubber microparticles in the butyl rubber slurry have a fast floating speed, and at the same time, the amount of diluent carried in the protective gas is small, so that the butyl rubber microparticles are quickly aggregated and the loss of diluent is reduced.

[0053] Further, the mass flow ratio of the protective gas to the butyl rubber slurry is 1:150-250.

[0054] According to the present application, the conditions of the concentration treatment include an operating temperature of -90℃ or lower and a residence time of 0.5-5min.

[0055] In the present application, the diluent containing unreacted monomers obtained by performing the concentration treatment under the above conditions has a low viscosity and can be directly used for the polymerization of butyl rubber. In particular, in the present application, the content of butyl rubber in the concentrated slurry can be controlled by adjusting the flow rate of the protective gas to the butyl rubber slurry and the residence time of the concentration treatment.

[0056] Further, the conditions of the concentration treatment include an operating temperature of -92℃ to -98℃ and a residence time of 1-3min.

[0057] According to the present application, the content of butyl rubber is 40-90wt% based on the total weight of the concentrated slurry.

[0058] Further, the content of the butyl rubber is 50-80wt% based on the total weight of the concentrated slurry.

[0059] According to the present application, the solvent is selected from at least one of C5-C8 linear, branched or cyclic alkanes, preferably selected from at least one of n-pentane, iso-pentane, cyclopentane, n-hexane, 2-methylpentane, 3-methylpentane, cyclohexane, methylcyclopentane, n-heptane, iso-heptane, n-octane and iso-octane, or more preferably n-hexane.

[0060] According to the present application, the temperature of the solvent is 20-70℃.

[0061] Further, the temperature of the solvent is 40-65℃.

[0062] According to the present application, the terminating agent is selected from at least one of C1-C5 saturated monohydric alcohols and / or C2-C4 saturated dihydric alcohols.

[0063] Further, the C1-C5 saturated monohydric alcohols are selected from at least one of methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, n-pentanol and iso-pentanol; and the C2-C4 saturated dihydric alcohols are selected from at least one of dipropylene glycol, triethylene glycol and tripropylene glycol.

[0064] Still further, the terminating agent is triethylene glycol (tri-glycol).

[0065] In the present application, the terminating agent can be added into the concentrated slurry alone or can be dissolved in a diluent in advance and then added into the concentrated slurry after mixing with the solvent.

[0066] According to the present application, the mass ratio of the terminating agent to the concentrated slurry is 1:350-800.

[0067] In the present application, when the mass ratio of the terminating agent to the concentrated slurry is controlled to meet the above range, the catalyst can be completely deactivated, and thus the halogenated butyl rubber base and the halogenated butyl rubber prepared therefrom can have excellent comprehensive performance.

[0068] Further, the mass ratio of the terminating agent to the concentrated slurry is 1:400-700.

[0069] According to the present application, the conditions of the dissolving and mixing include that the operating temperature is 0-60℃, the operating pressure is 110-250kPa and the residence time is 2-40min.

[0070] In the present application, the conditions of the dissolving and mixing are mild and the requirements for equipment are low, and thus the industrial production can be applied and the cost is significantly low.

[0071] Further, the dissolving and mixing conditions include: an operation temperature of 10-50℃, an operation pressure of 130-200kPa, and a residence time of 5-30min.

[0072] According to the present application, the content of the butyl rubber is 8-18wt%, preferably 10-15wt%, based on the total weight of the butyl rubber solution containing the diluent and unreacted monomers.

[0073] According to the present application, the rectification treatment conditions include: an operation temperature of -30℃ to 110℃, an operation pressure of 100-300kPa, and a reflux molar ratio of 5-35.

[0074] In the present application, the operation pressure required for the rectification treatment is low, and the number of trays required for the rectification can be reduced under the premise of ensuring good separation effect, thereby reducing the production cost.

[0075] Further, the rectification treatment conditions include: an operation temperature of -20℃ to 100℃, an operation pressure of 120-250kPa, and a reflux molar ratio of 10-25.

[0076] According to the present application, the rectification treatment includes rectification section treatment and stripping section treatment.

[0077] In the present application, the rectification treatment simultaneously includes rectification section treatment and stripping section treatment, and the butyl rubber solution containing the diluent and unreacted monomers is sequentially separated, which can directly achieve the purpose of removing the unreacted monomers and solvent in the glue solution and separating the solvent and diluent and unreacted monomers in one step, avoiding the use of hexane steam in the prior art for stripping treatment of the butyl rubber solution containing the diluent and unreacted monomers, obtaining a mixture containing the diluent, unreacted monomers and hexane, and further using a rectification tower for rectification separation of the mixture, and the butyl rubber solution obtained by stripping treatment is a viscous material, which is easy to foam and liquid film entrainment, and in order to prevent the butyl rubber from being carried out, 5-10 trays are usually arranged above the inlet position of the stripping tower, which causes the problems of complex process flow and high cost.

[0078] According to the present application, the rectification section treatment conditions include: an operation temperature of -30℃ to 90℃, an operation pressure of 100-215kPa, and a reflux molar ratio of 5-35.

[0079] In the present application, the operation pressure required for the rectification section treatment is low, and the number of trays required for the rectification section can be reduced under the premise of ensuring good separation effect, thereby reducing the production cost.

[0080] Further, the rectification section treatment conditions include: an operation temperature of -20℃ to 80℃, an operation pressure of 120-185kPa, and a reflux molar ratio of 10-25.

[0081] According to the present application, the conditions of the stripping section treatment include: an operating temperature of 70-110℃ and an operating pressure of 110-300kPa.

[0082] In the present application, the operating pressure required for the stripping section treatment is low, thus the butyl rubber glue solution obtained after the stripping section treatment has stable quality.

[0083] Further, the conditions of the stripping section treatment include: an operating temperature of 75-100℃ and an operating pressure of 135-250kPa.

[0084] According to the present application, the gas phase includes a diluent free of solvent and unreacted monomers.

[0085] According to the present application, the conditions of the cooling include: cooling the butyl rubber glue solution to 30-45℃.

[0086] According to the present application, the content of butyl rubber in the butyl rubber base glue solution for halogenation is 10-20wt%.

[0087] Further, the content of butyl rubber in the butyl rubber base glue solution for halogenation is 13-18wt%.

[0088] According to the present application, the content of isoprene in the butyl rubber base glue solution for halogenation is lower than 5ppm, preferably lower than 3ppm.

[0089] According to the present application, the diluent containing unreacted monomers obtained in step S1 can be returned to the butyl rubber polymerization reaction for the polymerization of butyl rubber.

[0090] In the present application, the part of the diluent containing unreacted monomers and catalyst obtained in step S1 is directly returned for the polymerization of butyl rubber, so that the content of catalyst in the butyl rubber base glue solution for halogenation is low, and the content of metal Al in the halogenated butyl product obtained after the halogenation of the glue solution is low, and the product quality is good.

[0091] According to the present application, the preparation method further includes: returning the gas phase obtained in step S3 to the butyl rubber polymerization reaction after being cooled by condensation for the polymerization of butyl rubber.

[0092] In the present application, the mode of the condensation cooling is not particularly limited, and the condensation of the gas phase obtained in step S3 can be realized by using the conventional mode in the art.

[0093] The second aspect of the present application provides a system for preparing a butyl rubber base glue solution for halogenation, characterized in that the system includes: a reaction kettle 1, a concentration device 2, a glue solution kettle 3 and a rectification tower 4.

[0094] The butyl rubber slurry from the reaction kettle 1 is introduced into the concentration device 2 from the upper part of the concentration device 2, and is in countercurrent contact with the protective gas from the bottom of the concentration device 2, and is subjected to concentration treatment to obtain concentrated slurry and diluent containing unreacted monomers, the concentrated slurry is discharged from the upper part of the concentration device 2, and the diluent containing unreacted monomers is discharged from the bottom of the concentration device 2;

[0095] The concentrated slurry is introduced into the sol kettle 3 and is subjected to dissolution and mixing with a solvent and a terminating agent to obtain a butyl rubber solution containing diluent and unreacted monomers;

[0096] The butyl rubber solution containing diluent and unreacted monomers is introduced into the rectifying tower 4 for rectification treatment, and the top of the rectifying tower obtains a gas phase, and the kettle obtains a butyl rubber glue liquid;

[0097] The butyl rubber glue liquid is cooled to obtain the butyl rubber base glue liquid for halogenation.

[0098] In the present application, the butyl rubber slurry from the reaction kettle 1 is directly subjected to concentration treatment in the concentration device 2, and the energy consumed in the processes of warming, vaporization, separation, recondensation and cooling is saved, and the energy consumption is reduced. In particular, in the method for preparing the glue liquid, the diluent does not contact with water, and impurities such as dimethyl ether are not generated, and the process of chloromethane refining and the like is saved, and the process can be reduced, and the cost can be significantly reduced.

[0099] Specifically, by controlling the butyl rubber slurry to be in countercurrent contact with the protective gas, the butyl rubber particles in the butyl rubber slurry can be made to float up by utilizing the difference in density between the butyl rubber particles and the diluent, and the separation of the butyl rubber, the unreacted monomers and the diluent in the butyl rubber slurry and the concentration of the butyl rubber are realized, and the concentrated slurry and the diluent containing unreacted monomers are obtained from the upper part and the bottom of the concentration device 2, respectively.

[0100] In the present application, the diluent containing unreacted monomers and catalyst obtained from the bottom of the concentration device 2 is directly returned for the polymerization of butyl rubber, so that the content of catalyst in the prepared butyl rubber base glue liquid for halogenation is low, the content of metal Al in the halogenated butyl product finally obtained after halogenation of the glue liquid is low, and the product quality is good.

[0101] Further, the concentrated slurry is introduced into the sol kettle 3 by pressure difference, and is subjected to dissolution and mixing with a solvent and a terminating agent, wherein the terminating agent can complex with the catalyst in the concentrated slurry, and the catalyst loses activity, and the butyl rubber particles in the concentrated slurry can be dissolved in the solvent to obtain the butyl rubber solution containing diluent and unreacted monomers.

[0102] In the present application, in order to ensure the separation effect of the rectification treatment, preferably, the butyl rubber solution containing diluent and unreacted monomer is introduced into the middle and / or upper part of the rectification tower for the rectification treatment.

[0103] According to the present application, the bottom of the concentration device 2 is provided with a gas distributor for uniformly dispersing the protective gas.

[0104] According to the present application, in the concentration device 2, the outlet of the concentration slurry is arranged opposite to the inlet of the butyl rubber slurry.

[0105] According to the present application, the outlet of the concentration slurry is 10-50 cm higher than the inlet of the butyl rubber slurry.

[0106] In the present application, when the difference between the position of the outlet of the concentration slurry and the inlet of the butyl rubber slurry meets the above range, the adjustment of the residence time of the concentration treatment process can be realized, and the content of butyl rubber in the concentration slurry meets the requirements of the present application.

[0107] Further, the outlet of the concentration slurry is 20-40 cm higher than the inlet of the butyl rubber slurry.

[0108] In the present application, the type of the solvaporation tank 3 is not particularly limited, and the conventional type in the art can be selected, preferably, the solvaporation tank 3 is a vertical stirring tank.

[0109] Further, the stirrer in the vertical stirring tank is selected from at least one of a helical ribbon stirrer, a turbine stirrer and an anchor stirrer, preferably a combination of an anchor stirrer and a helical ribbon stirrer.

[0110] According to the present application, the rectification tower 4 comprises a rectification section and a stripping section.

[0111] In the present application, the rectification tower simultaneously comprises rectification section treatment and stripping section treatment, and sequentially separates the butyl rubber solution containing diluent and unreacted monomer, which can directly achieve the purpose of removing unreacted monomer and solvent in the glue solution and separating the solvent and the diluent, the unreacted monomer, avoids the problem of complex process and high cost in the prior art, that is, in the stripping tower, the butyl rubber solution containing diluent and unreacted monomer is treated by using hexane steam to obtain a mixture containing diluent, unreacted monomer and hexane, which needs to be further separated by using a rectification tower, and the butyl rubber solution obtained by stripping treatment is a viscous material, which is easy to foam and liquid film entrainment, in order to prevent butyl rubber from being taken out from the top of the stripping tower, usually 5-10 trays are arranged above the inlet position of the stripping tower, which causes the problem of complex process and high cost.

[0112] According to the present application, the rectifying section adopts sieve tray, and the number of trays is 20-25.

[0113] According to the present application, the rectifying section adopts sieve tray, and the number of trays is 20-25.

[0114] In the present application, the system further comprises a reboiler 5, which is in communication with the rectifying column 4, and is used to heat part of the butyl rubber glue solution in the column bottom of the rectifying column 4 and return it to the rectifying column 4.

[0115] In the present application, after the heating treatment of the reboiler 5, part of the solvent in the butyl rubber glue solution is vaporized to generate an upward gas phase flow, which performs mass transfer and heat transfer with the downward flowing butyl rubber solution containing diluent and unreacted monomer to realize separation.

[0116] As shown in the specific embodiment of the present application, the preparation of the butyl rubber base glue solution for halogenation is carried out according to the following steps: Figure 1

[0117] In the reaction kettle 1, isobutene and isoprene are contacted in the presence of diluent and catalyst to perform cationic polymerization reaction to obtain the butyl rubber slurry;

[0118] The butyl rubber slurry from the top of the reaction kettle 1 is introduced into the concentration device 2 from the upper part of the concentration device 2 by overflow, and is contacted with the protective gas from the bottom of the concentration device 2 in countercurrent to perform concentration treatment to obtain concentrated slurry and diluent containing unreacted monomer, the concentrated slurry is discharged from the upper part of the concentration device 2, and the diluent containing unreacted monomer is discharged from the bottom of the concentration device 2; the diluent containing unreacted monomer is returned to the reaction kettle 1 by pump for polymerization of butyl rubber;

[0119] The concentrated slurry from the upper part of the concentration device 2 is introduced into the sol kettle 3, and is mixed with solvent and terminator to obtain butyl rubber solution containing diluent and unreacted monomer;

[0120] The butyl rubber solution containing diluent and unreacted monomer is introduced into the middle and / or upper part of the rectifying column 4 containing the rectifying section and the stripping section by pump, and is sequentially subjected to rectifying section treatment and stripping section treatment, the gas phase containing no solvent and unreacted monomer is obtained at the top of the column, and the butyl rubber glue solution substantially containing no unreacted monomer is obtained at the column bottom; the gas phase obtained at the top of the column is condensed by a condenser, part of which is returned to the top of the column as reflux liquid, and the rest is cooled by a cooler and then returned to the reaction kettle 1 for polymerization of butyl rubber; the butyl rubber glue solution obtained at the column bottom is cooled to obtain the butyl rubber base glue solution for halogenation.

[0121] ​The third aspect of the present application provides a use of the method or system for preparing the butyl rubber base solution for halogenation in preparing the butyl rubber base solution for halogenation.

[0122] The present application will be described in detail below through examples.

[0123] The butyl rubber mass content in the butyl rubber solution containing diluent and unreacted monomers, the butyl rubber solution and the butyl rubber base solution for halogenation (collectively referred to as the solution) in the following examples is measured according to the following method:

[0124] Take a 150 mL beaker, weigh it, record it as W0, take about 2 g of the solution in a 150 mL beaker, quickly weigh it, record its mass as W1, place the beaker in a constant temperature electric heating jacket at 120°C and heat for 5 min, then place it in a desiccator and cool for 10 min, then weigh it again, record its mass as W2, then the butyl rubber mass content in the solution is:

[0125] The butyl rubber mass content in the solution, wt% = (W2-W0) / (W1-W0) x 100%.

[0126] Analysis of isoprene content in the solution: headspace chromatography is used. About 0.1 g of sample is placed in a special headspace chromatography bottle, and after vaporization at 70°C for 30 min in a heating furnace, a certain amount of vaporized sample is taken through a quantitative valve for chromatographic analysis. The chromatographic conditions are: constant temperature at 35°C for 10 min, then increase the temperature at a rate of 10°C / min to 260°C, and then constant temperature for 30 min.

[0127] Analysis of overhead components: gas chromatography is used for analysis. The chromatographic conditions are: constant temperature at 35°C for 10 min, then increase the temperature at a rate of 10°C / min to 260°C, and then constant temperature for 30 min.

[0128] The butyl rubber mass content in the butyl rubber slurry and the concentrated slurry is calculated according to the following method:

[0129] Mass flow rate of the outlet of the sol pot x butyl rubber mass content in the solution at the outlet of the sol pot / mass flow rate of the slurry x 100%.

[0130] The calculation method of energy consumption: energy consumption required for cooling the material (N2) + energy consumption required for heating the material (hexane) + energy consumption of the overhead condenser of the rectification tower + energy consumption of the tower bottom reboiler of the rectification tower + energy consumption of cooling the butyl rubber solution + energy consumption of cooling the diluent returned to the reaction kettle 1. The electric energy consumption of the moving equipment (including pumps and mixers) is ignored.

[0131] Example 1

[0132] S1, the butyl rubber slurry with a temperature of -95°C and a mass flow rate of 7142 kg / h discharged from the top of the reactor 1 is fed into the concentration device 2, and nitrogen gas with a temperature of -95°C is introduced into the bottom of the concentration device 2, and the operating temperature of the concentration device is -95°C. The mass flow rate ratio of nitrogen gas to butyl rubber slurry is 1:200, and the residence time of the slurry in the concentration device is 1.5 min, and the concentrated slurry is obtained.

[0133] S2, the concentrated slurry is directly discharged from the upper part of the device into the sol tank 3 with a mass flow rate of 4000 kg / h, and the diluent containing unreacted monomers is discharged from the bottom of the device and returned to the reactor 1 through a pump. In the concentration device 2, the outlet of the concentrated slurry is 30 cm higher than the inlet of the butyl rubber slurry.

[0134] At the same time that the concentrated slurry flows into the sol tank 3, the sol tank is added with solvent n-hexane and terminating agent triethylene glycol, the temperature of n-hexane is 40°C, the mass flow rate is 16000 kg / h, and the mass ratio of the terminating agent triethylene glycol to the concentrated slurry is 1:650. The operating temperature of the sol tank is 30°C, the operating pressure is 150 kPa, and the residence time is 10 min, and the butyl rubber solution containing diluent and unreacted monomers is formed in the sol tank 3, in which the mass content of butyl rubber is 10 wt%.

[0135] S3, the butyl rubber solution containing diluent and unreacted monomers in the sol tank 3 is pumped into the rectifying column 4 with a mass flow rate of 20000 kg / h. The rectifying column 4 comprises a rectifying section and a stripping section, the number of trays in the rectifying section is 20, and the number of trays in the stripping section is 45, and the processing conditions of the rectifying section include: the operating temperature is -14°C to 55°C, the operating pressure is 150-162 kPa, and the reflux molar ratio is 15; the processing conditions of the stripping section include: the operating temperature is 55°C-90°C, the operating pressure is 162-190 kPa. The gas phase is obtained at the top of the column, and the butyl rubber gum solution is obtained at the bottom of the column, and the halogenated butyl rubber base gum solution is obtained by cooling the butyl rubber gum solution to 40°C.

[0136] The amount of materials used in each step and the specific process conditions are shown in Table 1. The butyl rubber content in the slurry or gum solution, the n-hexane content at the top of the column, the isoprene content at the bottom of the column, and the energy consumption data are shown in Table 2.

[0137] Examples 2-10

[0138] The halogenated butyl rubber base gum solution is prepared according to the method of Example 1, except that the amount of materials used in each step and the specific process conditions are different from those of Example 1, and the specific conditions are shown in Table 1. The butyl rubber content in the slurry or gum solution, the n-hexane content at the top of the column, the isoprene content at the bottom of the column, and the energy consumption data are shown in Table 2.

[0139] Table 1

[0140]

[0141] Table 1 (continued)

[0142]

[0143] Comparative Example 1

[0144] The method of Example 1 was followed, except that step S1 was not used, and the butyl rubber slurry discharged from the top of reactor 1 at a temperature of -95°C and a mass flow rate of 7142 kg / h was directly fed into the sol tank 3, at which time all of the diluent and unreacted monomer in reactor 1 was discharged as a gas phase from the top of rectification column 4, and returned to the polymerization tank after condensation.

[0145] The butyl rubber content in the slurry or gum solution, the n-hexane content at the top of the column, the isoprene content at the bottom of the column, and the energy consumption data are shown in Table 2.

[0146] Comparative Example 2

[0147] The method of Example 1 was followed, except that the rectification column of step S3 was replaced by a stripping column and a rectification column, wherein the operating conditions of the stripping column were: temperature 70-90°C, pressure 150-190 kPa, mass ratio of gas phase feed flow rate at the bottom of the column to liquid phase feed flow rate at the top of the column was 1:1, gas phase feed temperature at the bottom of the column was 120°C, and mass reflux ratio was 0.2. The operating conditions of the rectification column were: temperature -18-82°C, pressure 120-150 kPa, and mass reflux ratio was 35. The gas phase containing hexane collected at the top of the stripping column was fed into the rectification column for separation, the components collected at the top of the rectification column were returned to the polymerization tank, and hexane was collected at the bottom of the column.

[0148] The butyl rubber content in the slurry or gum solution, the n-hexane content at the top of the column, the isoprene content at the bottom of the column, and the energy consumption data are shown in Table 2.

[0149] Table 2

[0150]

[0151] Table 2 (continued)

[0152]

[0153] As can be seen from Table 2, when the method provided by the present application is used to prepare butyl rubber base gum solution for halogenation, the gas phase obtained at the top of the column does not contain n-hexane. Compared with Comparative Examples 1 and 2, when the method provided by Examples 1-10 of the present application is used to prepare butyl rubber base gum solution for halogenation, the energy consumption required by the method can be significantly reduced while ensuring that the isoprene content in the prepared butyl rubber base gum solution for halogenation does not increase significantly.

[0154] Compared with Example 1, the mass flow of nitrogen and butyl rubber slurry in Example 8 is larger, and the amount of nitrogen is more, but the mass content of butyl rubber in the rubber solution in the sol tank is the same, which indicates that the butyl rubber particles have all floated, and increasing the nitrogen will only cause the increase of energy consumption.

[0155] Compared with Example 1, the mass flow of nitrogen and butyl rubber slurry in Example 9 is smaller, and the amount of nitrogen is lower, so that the butyl rubber particles in the butyl rubber slurry cannot all float, resulting in the lower mass content of butyl rubber in the rubber solution in the sol tank, and causing the loss of polymer.

[0156] Compared with Example 1, the outlet of the concentrated slurry in Example 10 is 8 cm higher than the inlet of the butyl rubber slurry, so that the butyl rubber particles in the butyl rubber slurry cannot all float, resulting in the lower mass content of butyl rubber in the sol tank, and causing the loss of polymer.

[0157] Compared with Example 1, in Example 5 and Example 6, the lower molar ratio of reflux treated in the rectification section causes the disadvantageous increase of isoprene content in the butyl rubber base solution for halogenation prepared.

[0158] Compared with Example 1, in Example 7, the higher molar ratio of reflux treated in the rectification section causes the significant increase of energy consumption, although the isoprene content in the butyl rubber base solution for halogenation prepared is reduced.

[0159] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as the disclosed content of the present application, and all belong to the protection scope of the present application.

Claims

1. A process for preparing a butyl rubber base solution for halogenation, characterized by, The preparation method comprises the following steps: S1, the butyl rubber slurry from butyl rubber polymerization reaction is contacted with protective gas countercurrently for concentration treatment, and concentrated slurry and diluent containing unreacted monomer are obtained; S2, the concentrated slurry is mixed with solvent and terminator for dissolution, and butyl rubber solution containing diluent and unreacted monomer is obtained; S3, the butyl rubber solution containing diluent and unreacted monomer is treated by rectification, and gas phase and butyl rubber glue liquid are obtained, and the butyl rubber glue liquid is cooled to obtain the butyl rubber base glue liquid for halogenation; In step S1, the butyl rubber slurry is introduced from the upper part of the concentration device, and the protective gas is introduced from the lower part of the concentration device; The mass flow ratio of the protective gas to the butyl rubber slurry is 1:100-300; The outlet of the concentrated slurry is 10-50 cm higher than the inlet of the butyl rubber slurry; The rectification treatment comprises rectification section treatment and stripping section treatment; The conditions of the rectification section treatment comprise: the operating temperature is-30℃ to 90℃, the operating pressure is 100-215kPa, and the reflux molar ratio is 15-25; The conditions of the stripping section treatment comprise: the operating temperature is 70℃ to 110℃, and the operating pressure is 110-300kPa; The rectification section treatment adopts sieve plate tray, and the number of trays is 20-25; The stripping section treatment adopts guide sieve plate tray, and the number of trays is 40-55.

2. The method of claim 1, wherein, The content of the butyl rubber is 20-40wt% based on the total weight of the butyl rubber slurry.

3. The method of claim 1 or 2, wherein, The temperature of the butyl rubber slurry is-100℃ to-88℃.

4. The method of claim 1 or 2, wherein, The butyl rubber slurry is prepared by the following method: In the presence of diluent and catalyst, isobutene and isoprene are contacted to carry out cationic polymerization reaction, and the butyl rubber slurry is obtained.

5. The method of claim 4, wherein, The temperature of the cationic polymerization reaction is-90℃ to-98℃.

6. The method of claim 1 or 2, wherein, The diluent is selected from at least one of chloromethane, chloroethane and dichloromethane.

7. The method of claim 1 or 2, wherein, The protective gas is selected from nitrogen and / or inert gas.

8. The method of claim 1 or 2, wherein, The protective gas is nitrogen.

9. The method of claim 1 or 2, wherein, The temperature of the protective gas is-90℃ or lower.

10. The method of claim 1 or 2, wherein, The temperature of the protective gas is-92℃ to-98℃.

11. The method of claim 1 or 2, wherein, The mass flow ratio of the protective gas to the butyl rubber slurry is 1:150-250.

12. The method of claim 1 or 2, wherein, The conditions of the concentration treatment comprise: the operating temperature is-90℃ or lower, and the residence time is 0.5-5min.

13. The method of claim 1 or 2, wherein, The conditions of the concentration treatment comprise: the operating temperature is-92℃ to-98℃, and the residence time is 1-3min.

14. The method of claim 1 or 2, wherein, The content of the butyl rubber is 40-90wt% based on the total weight of the concentrated slurry.

15. The method of claim 1 or 2, wherein, The content of the butyl rubber is 50-80wt% based on the total weight of the concentrated slurry.

16. The method of claim 1 or 2, wherein, The solvent is selected from at least one of C5-C8 straight chain, branched chain or cyclic alkanes.

17. The method of claim 1 or 2, wherein, The solvent is selected from at least one of n-pentane, isopentane, cyclopentane, n-hexane, 2-methylpentane, 3-methylpentane, cyclohexane, methylcyclopentane, n-heptane, isopentane, n-octane and isooctane.

18. The method of claim 1 or 2, wherein, The solvent is n-hexane.

19. The method of claim 1 or 2, wherein, The temperature of the solvent is 20-70℃.

20. The method of claim 1 or 2, wherein, The terminating agent is selected from C1-C5 saturated monohydric alcohols and / or C2-C4 saturated dihydric alcohols.

21. The method of claim 1 or 2, wherein, The mass ratio of the terminating agent to the concentrated slurry is 1:350-800.

22. The method of claim 1 or 2, wherein, The mass ratio of the terminating agent to the concentrated slurry is 1:400-700.

23. The method of claim 1 or 2, wherein, The conditions of the dissolving mixing include: the operating temperature is 0-60℃, the operating pressure is 110-250kPa, and the residence time is 2-40min.

24. The method of claim 1 or 2, wherein, The content of the butyl rubber is 8-18wt% based on the total weight of the butyl rubber solution containing diluent and unreacted monomer.

25. The method of claim 1 or 2, wherein, The content of the butyl rubber is 10-15wt% based on the total weight of the butyl rubber solution containing diluent and unreacted monomer.

26. The method of claim 1 or 2, wherein, The gas phase includes diluent and unreacted monomer without solvent.

27. The method of claim 1 or 2, wherein, The conditions of the cooling include: cooling the butyl rubber solution to 30-45℃.

28. The method of claim 1 or 2, wherein, The content of butyl rubber in the butyl rubber base solution for halogenation is 10-20wt%.

29. The method of claim 1 or 2, wherein, The content of isoprene in the butyl rubber base solution for halogenation is less than 5ppm.

30. The method of claim 1 or 2, wherein, The content of isoprene in the butyl rubber base solution for halogenation is less than 3ppm.

31. The method of claim 1 or 2, wherein, The preparation method further includes: returning the diluent containing unreacted monomer obtained in step S1 to the butyl rubber polymerization reaction.

32. The method of claim 1 or 2, wherein, The preparation method further includes: returning the gas phase obtained in step S3 to the butyl rubber polymerization reaction after condensation cooling.

33. A system for preparing a butyl rubber base solution for halogenation, characterized by, The system includes: a reaction kettle (1), a concentration device (2), a solution kettle (3) and a rectification column (4); The butyl rubber slurry from the reaction kettle (1) is introduced into the upper part of the concentration device (2) to contact with the protective gas from the bottom of the concentration device (2) in countercurrent, and is subjected to concentration treatment to obtain concentrated slurry and diluent containing unreacted monomer, the concentrated slurry is discharged from the upper part of the concentration device (2), and the diluent containing unreacted monomer is discharged from the bottom of the concentration device (2); the concentrated slurry is introduced into the solution kettle (3) to be subjected to dissolving mixing with solvent and terminating agent to obtain butyl rubber solution containing diluent and unreacted monomer; The butyl rubber solution containing diluent and unreacted monomer is introduced into the rectification column (4) to be subjected to rectification treatment, the gas phase is obtained from the top of the rectification column, and the butyl rubber solution is obtained from the kettle. The butyl rubber solution is cooled to obtain the butyl rubber base solution for halogenation. The outlet of the concentrated slurry is 10-50cm higher than the inlet of the butyl rubber slurry. The rectification column (4) includes a rectification section and a stripping section. The rectification section adopts sieve tray, and the number of trays is 20-25. The stripping section adopts guide sieve tray, and the number of trays is 40-55.

34. The system of claim 33, wherein, The bottom of the concentration device (2) is provided with a gas distributor for uniformly dispersing the protective gas.

35. The system of claim 33, wherein, In the concentration device (2), the outlet of the concentrated slurry is oppositely arranged with the inlet of the butyl rubber slurry.

36. The system of claim 33, wherein, The outlet of the concentrated slurry is 20-40cm higher than the inlet of the butyl rubber slurry.

37. The system of any of claims 33-36, wherein, The sol kettle (3) is a vertical stirred tank.

38. The system of claim 37, wherein, The stirrer in the vertical stirred tank is selected from at least one of a helical ribbon stirrer, a turbine stirrer and an anchor stirrer.

39. Use of the process for producing a butyl rubber base solution for halogenation according to any one of claims 1 to 32 or the system for producing a butyl rubber base solution for halogenation according to claim 37 or 38 for producing a butyl rubber base solution for halogenation.

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