Continuous preparation device of polyether polyol

Abstract

The utility model relates to a continuous preparation device of polyether polyol, which belongs to the technical field of chemical engineering and comprises a catalyst preparation tank, a catalyst feeding tank, a front loop reactor, a rear loop reactor, a curing tank, a filter and a stripping tower. A discharge port of the catalyst preparation tank is communicated with a feed port of the catalyst feeding tank through a material pipe, a discharge port of the catalyst feeding tank is communicated with a feed port of the front loop reactor through a material pipe, and a discharge port of the front loop reactor is communicated with a feed port of the rear loop reactor through a material pipe. The reactor has the advantages that the temperature difference of a reaction system is small, and the reaction efficiency is high; the reaction system has the characteristics of no gas phase space, high equipment space-time yield, high reaction system mixing degree, few side reactions, narrow molecular weight distribution, low product viscosity and the like.

Description

Technical Field

[0001] The utility model relates to a continuous preparation device for polyether polyol, belonging to the technical field of chemical engineering. Background Art

[0002] Polyether polyol (referred to as polyether for short) is prepared by the addition polymerization reaction of an initiator (a compound containing an active hydrogen group) and an epoxide (such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), etc.) in the presence of a catalyst. The largest output of polyether is produced with glycerol (glycerol) as the initiator and epoxides (usually a combination of PO and EO). By changing the feeding methods (mixed feeding or separate feeding), dosage ratios, feeding sequences, etc. of PO and EO, various general-purpose polyethers can be produced. Polyether is mainly applied in the field of polyurethane materials, used for producing polyurethane flexible foams, rigid foams, polyurethane coatings, adhesives, sealants, elastomers and other products, and its consumption accounts for about 80% of the total polyether production. In addition, polyether is also applied in the production of foam stabilizers, defoamers, demulsifiers, lubricants and other aspects.

[0003] The double metal cyanide (DMC) catalyst used for synthesizing polyether with low unsaturation has the characteristics of strong catalytic activity and fast reaction speed. High molecular weight polyether can be prepared with DMC as the catalyst. The prepared polyether has the advantages of low unsaturation of the product, extremely low content of monohydric alcohol, the functionality of the product close to the theoretical value, and narrow molecular weight distribution. At present, the main production method in industry is the batch process, and there are many drawbacks in the batch process, mainly including low utilization rate of the reaction kettle, long production cycle, unstable quality indicators between batches, etc. In addition, there is also a DMC continuous process in industrial production, which can well overcome the drawbacks of the batch process. Monomers and initiators enter the reactor continuously as raw materials for polymerization reaction to produce difunctional or polyfunctional polyether polyols, with low unsaturation and narrow molecular weight distribution of the products. At the same time, according to market demand, the ratio of initiator and monomer in the formula can be adjusted to produce polyether products with different molecular weights or grades. After the polymerization reaction, the catalyst does not need to be treated and is carried out with the product.

[0004] Patent CN01805522.2 discloses a method for preparing polyether polyol by reacting a diol or polyol with ethylene oxide, propylene oxide, butylene oxide or a mixture thereof in the presence of a multi-metal cyanide coordination catalyst. This process is carried out in a vertical, high cylindrical reactor, which has a central stirrer and many heat exchange plates, and a heat exchange medium flows in the heat exchange plates. These heat exchange plates are basically arranged longitudinally along the reactor and are arranged at an α angle of 0 to 70 degrees relative to the radius of the reactor along the direction of the stirrer rotation.

[0005] Patent CN200480006142.3 discloses a continuous method and apparatus for preparing polyether polyols, which can continuously add unreacted oxides into a loop reactor, and at the same time add at least one heat deactivation catalyst with heat deactivation ability into the loop reactor before the decomposition of the polyether polyol, and can obtain a higher concentration of unreacted oxides and / or a reaction rate at least twice as fast as that in a loop reactor containing less than 14 wt% unreacted oxides. In a preferred embodiment, the catalyst is a double metal cyanide catalyst, and a plug flow reactor is connected in series with the loop reactor, and neither of the reactors contains a vapor space.

[0006] Patent CN200420024662.4 discloses a chemical production process equipment, especially for polyether polyol production. The equipment includes a polyether production reactor and a small mixing kettle; a metering device, a heating device or a flowmeter is added at the lower end of the small mixing kettle for accurate metering. The volume of the small mixing kettle is preferably between 1 L and 100 L. When using a double metal cyanide complex catalyst to produce polyether, this device will not cause waste of raw materials due to the addition of the double metal cyanide complex catalyst, shortens the reaction time, and reduces the production cost.

[0007] The disadvantages of the prior art are as follows:

[0008] The prior art usually adopts the batch method for production, with low utilization rate of the reactor, long production cycle, and unstable quality indicators among batches, etc. Utility Model Content

[0009] To overcome the defects of the prior art, the present utility model provides a continuous preparation device for polyether polyols. The technical solution of the present utility model is:

[0010] A continuous preparation device for polyether polyol, comprising a catalyst preparation tank, a catalyst feeding tank, a front loop reactor, a rear loop reactor, a curing tank, a filter and a stripping tower. The catalyst preparation tank is located above the catalyst feeding tank. The discharge port of the catalyst preparation tank is communicated with the feed port of the catalyst feeding tank through a material pipe. The discharge port of the catalyst feeding tank is communicated with the feed port of the front loop reactor through a material pipe. The discharge port of the front loop reactor is communicated with the feed port of the rear loop reactor through a material pipe. The discharge port of the rear loop reactor is connected with the feed port of the curing tank through a material pipe. The discharge port of the curing tank is communicated with the feed port of the filter. The discharge port of the filter is connected to the stripping tower through a material pipe. The front loop reactor and the rear loop reactor have the same structure. The material pipe communicated with the feed port of the front loop reactor is close to the inlet of the pump of the front loop reactor; the raw materials are fully mixed by the pump of the front loop reactor; the material pipe communicated with the rear loop reactor is close to the outlet of the heat exchanger of the rear loop reactor; it further comprises a raw material feeding pipe, and the discharge end of the raw material feeding pipe is connected to the front loop reactor, and the discharge end of the raw material feeding pipe is close to the inlet of the pump of the front loop reactor.

[0011] A stirring component is arranged inside the catalyst preparation tank, and a cooling jacket is sleeved outside.

[0012] The slurry in the catalyst preparation tank flows into the catalyst feeding tank by gravity.

[0013] The VOC or light component substances at the top of the stripping tower are discharged from the top of the tower and then connected to a vacuum system; the crude polyether product is output at the bottom of the stripping tower.

[0014] The front loop reactor, the rear loop reactor, the curing tank and the filter together form a reaction system.

[0015] The advantages of the present utility model are as follows:

[0016] 1. Combining the characteristics of high reaction activity and rapid polymerization reaction of the bimetallic catalyst, an efficient loop reactor is selected to enable the material to obtain a linear velocity of 1.8 - 2.6 m / s in the reaction system, which is beneficial to increasing the degree of chaos of the fluid during the reaction process, enabling the raw materials to be quickly and evenly mixed, and thus being more conducive to obtaining a product with a narrower molecular weight distribution in the polymerization reaction. This reactor has the characteristics of small temperature difference in the reaction system, high reaction efficiency; no gas phase space in the reaction system, high space-time yield of the equipment, high degree of mixing in the reaction system, few side reactions, narrow molecular weight distribution, and low product viscosity.

[0017] 2. A small amount of catalyst particles do not fully stratify throughout the reaction process. By removing the remaining larger catalyst particles in the reaction products, the adverse effects on the foaming process of polyether polyol for end-users are reduced. After the crude product undergoes stripping treatment, the VOC content is extremely low, improving the quality of the foaming products for end-users. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the main structure of the present utility model.

[0019] Figure 2 It is a schematic diagram of the working principle of the present utility model. Detailed Embodiments

[0020] The present utility model will be further described below in conjunction with specific embodiments. The advantages and features of the present utility model will become clearer with the description. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present utility model. Those skilled in the art should understand that modifications or substitutions can be made to the details and forms of the technical solution of the present utility model without departing from the spirit and scope of the present utility model, but such modifications and substitutions all fall within the protection scope of the present utility model.

[0021] Refer to Figure 1 and Figure 2 The present utility model relates to a continuous preparation device for polyether polyol, including a catalyst preparation tank 1, a catalyst feeding tank 2, a front loop reactor 3, a rear loop reactor 4, a curing tank 5, a filter 6, and a stripping tower 7. The catalyst preparation tank 1 is located above the catalyst feeding tank 2. The discharge port of the catalyst preparation tank 1 is connected to the feed port of the catalyst feeding tank 2 through a feed pipe. The discharge port of the catalyst feeding tank 2 is connected to the feed port of the front loop reactor 3 through a feed pipe. The discharge port of the front loop reactor 3 is connected to the feed port of the rear loop reactor 4 through a feed pipe. The discharge port of the rear loop reactor 4 is connected to the feed port of the curing tank 5 through a feed pipe. The discharge port of the curing tank 5 is connected to the feed port of the filter 6. The discharge port of the filter is connected to the stripping tower 7 through a feed pipe. The front loop reactor 3, the rear loop reactor 4, the curing tank 5, and the filter 6 together form a reaction system.

[0022] Based on the above structural settings, the following are achieved:

[0023] Continuous production: By processing continuously flowing materials, production interruptions can be reduced and production efficiency can be improved.

[0024] High degree of automation: Each component is connected through a feed pipe, enabling automated control, reducing manual operations, and lowering production costs.

[0025] Reaction efficiency: The series use of the front loop reactor and the rear loop reactor can provide a longer reaction time, improving the reaction efficiency and product quality.

[0026] High catalyst utilization rate: The design of the catalyst preparation tank and the catalyst feeding tank can ensure the uniform dispersion and efficient use of the catalyst.

[0027] Aging process: The aging tank can provide a suitable environment for the reaction products to have sufficient time for post-treatment, improving the performance of the final product.

[0028] Filtration and purification: The use of filters can remove impurities generated during the reaction process, ensuring the purity of the product.

[0029] Stripping separation: The stripping column can effectively separate the solvent or unreacted raw materials from the reaction products, improving the product purity and at the same time recovering the reusable solvent or raw materials.

[0030] The structures of the front loop reactor 3 and the rear loop reactor 4 are the same. The feed pipe communicating with the feed inlet of the front loop reactor 3 is close to the inlet of the pump of the front loop reactor 3; the raw materials are fully mixed by the pump of the front loop reactor 3; the feed pipe communicating with the rear loop reactor 4 is close to the outlet of the heat exchanger of the rear loop reactor 4; it also includes a raw material feed pipe, and the discharge end of this raw material feed pipe is connected to the front loop reactor 3, and the discharge end of this raw material feed pipe is close to the inlet of the pump of the front loop reactor.

[0031] The setting of this structure realizes the following advantages:

[0032] Uniform mixing: Through the pump of the front loop reactor 3, the raw materials are fully mixed, which helps to improve the uniformity and efficiency of the reaction.

[0033] Continuous feeding: The design of the raw material feed pipe allows continuous addition of auxiliary materials during the reaction process, which helps to maintain the stability and continuity of the reaction.

[0034] Inside the catalyst preparation tank 1, there is a stirring component, and an outer cooling jacket is sleeved.

[0035] The slurry in the catalyst preparation tank 1 flows into the catalyst feeding tank 2 by gravity. The VOC or light component substances at the top of the stripping column 7 are discharged from the top of the column and then connected to the vacuum system; the crude polyether product is output at the bottom of the stripping column 7.

[0036] The working principle of the present utility model is:

[0037] The catalyst is added batchwise to the catalyst preparation tank and stirring is started to obtain a homogeneous slurry mixture. The catalyst preparation tank is equipped with a cooling jacket, and cooling water is introduced to cool the propylene glycol to prevent the catalyst from deactivating due to excessive temperature of the propylene glycol. After the catalyst DMC and propylene glycol PG are mixed under nitrogen conditions, the slurry flows by gravity into the catalyst feed tank. In the catalyst feed tank, the slurry is kept constant and then circulated to prevent the suspended catalyst particles from settling. Heat is generated in the system during the continuous circulation process, and the temperature needs to be maintained by the jacket cooling water.

[0038] Among them, DMC: double metal cyanide catalyst; EO: ethylene oxide; PO: propylene oxide; PG: propylene glycol; BG: glycerol (glycerin); PPG: polyether polyol; CWS: circulating cooling water supply; CWR: circulating cooling water return; LS: low-pressure steam.

[0039] The above-mentioned EO, PO, PG, and BG are used as raw materials and catalysts. After being accurately metered, they enter the front loop reactor for mixing, and are circulated and heat-exchanged through the circulation pump supporting the loop reactor. Among them, the above-mentioned raw materials include that after circulation and heat exchange, the material flows out from the top of the front loop reactor to the rear loop reactor, and after circulation and heat exchange, the material flows out from the top of the rear loop reactor and enters the aging tank for continuous reaction. The aged product passes through a filter to remove the larger catalyst particles remaining in the reaction product.

[0040] The crude polyol product after removing the catalyst particles enters from the top of the stripping column after depressurization, and steam is introduced into the bottom of the column after depressurization. After the steam at the bottom of the column contacts the liquid material at the top of the column in a countercurrent manner, VOC or light component substances are discharged from the top of the column.

[0041] The liquid product polyether polyol discharged from the bottom of the stripping column is processed through multiple continuous steps. According to the requirements of different grade products, antioxidants, phosphoric acid, nitrogen, etc. are added, and finally the polyether polyol product is obtained.

[0042] Taking JM4000 polyether polyol as an example:

[0043] Propylene glycol (HG / T 4980-2016) and propylene oxide (GB14491-2015 first-class product) are selected as raw materials, DMC is used as the catalyst, and auxiliary materials include phosphoric acid, antioxidant, etc. to produce JM4000 polyether polyol, and a set of continuous polyether polyol preparation device is designed.

[0044] This device consists of a catalyst preparation tank, a catalyst feed tank, a front loop reactor, a rear loop reactor, an aging tank, a filter, a stripping column, and a corresponding control system;

[0045] Add 26.9 kg of propylene glycol to the catalyst preparation tank, turn on the stirring and circulating cooling water, add 0.1 kg of DMC through the feeding funnel, and stir for 45 minutes to obtain a uniform slurry mixture;

[0046] The catalyst and propylene glycol mixed slurry flows into the catalyst feeding tank by gravity. In the catalyst feeding tank, after the slurry is kept constant, it is circulated to prevent the suspended catalyst particles from settling. Turn on the circulating cooling water to keep the temperature constant;

[0047] The catalyst and propylene glycol mixed slurry, raw propylene glycol (containing 1.5% nitrogen), and raw propylene oxide are accurately metered and then added to the front loop reactor at the same time. The flow rates are 1.12 kg / h, 1.75 kg / h, and 147.2 kg / h respectively. Turn on the circulating pump supporting the loop reactor for circulation. The front loop reactor is full of liquid, the temperature is controlled at 140 °C, and the operating pressure is about 1.0 MPaG;

[0048] After the material is circulated and heat-exchanged in the front loop reactor, it flows out from the top of the front loop reactor to the rear loop reactor, with a flow rate of about 150.1 kg / h. The rear loop reactor is full of liquid, the temperature is controlled at 140 °C, and the operating pressure is controlled by the downstream pressure regulating valve, and the operating pressure is about 1.0 MPaG;

[0049] After being circulated and heat-exchanged, the material flows out from the top of the rear loop reactor and enters the ripening tank to continue the reaction, with a flow rate of about 150.1 kg / h. The reaction temperature rise is about 5 °C. The reaction product passes through a filter to remove the larger catalyst particles remaining in the reaction product.

[0050] The crude polyol product after removing the catalyst particles enters from the top of the stripping column after depressurization. 5 barG superheated steam is introduced into the bottom of the column after depressurization, and the steam flow rate is 18 kg / h. After the steam at the bottom of the column contacts the liquid material at the top of the column countercurrently, VOC or light components are discharged from the top of the column to the waste gas treatment. The operating pressure at the top of the stripping column is 4 kPaA, and the temperature is 140 °C. The crude product polyether polyol is withdrawn from the bottom of the stripping column at a flow rate of about 150 kg / h;

[0051] According to the product requirements of polyether polyol JM4000, antioxidants, phosphoric acid, nitrogen, etc. are added to finally obtain the polyether polyol JM4000 product.

[0052] As mentioned above, it is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A continuous preparation device for polyether polyol, characterized in that, It includes a catalyst preparation tank, a catalyst feeding tank, a front loop reactor, a rear loop reactor, a ripening tank, a filter and a stripping tower. The catalyst preparation tank is located above the catalyst feeding tank. The discharge port of the catalyst preparation tank is communicated with the feed port of the catalyst feeding tank through a material pipe. The discharge port of the catalyst feeding tank is communicated with the feed port of the front loop reactor through a material pipe. The discharge port of the front loop reactor is communicated with the feed port of the rear loop reactor through a material pipe. The discharge port of the rear loop reactor is connected with the feed port of the ripening tank through a material pipe. The discharge port of the ripening tank is communicated with the feed port of the filter. The discharge port of the filter is connected to the stripping tower through a material pipe.

2. The continuous preparation device of polyether polyol according to claim 1, characterized in that, The front loop reactor and the rear loop reactor have the same structure. The material pipe communicated with the feed port of the front loop reactor is close to the inlet of the pump of the front loop reactor; the raw materials are fully mixed by the pump of the front loop reactor; the material pipe communicated with the rear loop reactor is close to the outlet of the heat exchanger of the rear loop reactor; it also includes a raw material feed pipe, and the discharge end of the raw material feed pipe is connected to the front loop reactor, and the discharge end of the raw material feed pipe is close to the inlet of the pump of the front loop reactor.

3. The continuous preparation device of polyether polyol according to claim 1, characterized in that, A stirring component is arranged inside the catalyst preparation tank, and a cooling jacket is sleeved outside.

4. The continuous preparation device of polyether polyol according to claim 2 or 3, characterized in that, The slurry in the catalyst preparation tank flows into the catalyst feeding tank by gravity.

5. The continuous preparation device of polyether polyol according to claim 4, characterized in that, The VOC or light component substances at the top of the stripping tower are discharged from the tower top and then connected to a vacuum system; the crude polyether product is output at the bottom of the stripping tower.

6. The continuous preparation device of polyether polyol according to claim 4, characterized in that, The front loop reactor, the rear loop reactor, the ripening tank and the filter together form a reaction system.

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