CN217473482U - Reaction device for producing polyether polyol with low unsaturation degree - Google Patents

Abstract

The utility model relates to a reaction unit for producing polyether polyol with low unsaturation degree, which comprises a polymerization reactor, a vaporizer, a nitrogen supply system and an initiation kettle, wherein the outlet of the vaporizer is connected with the nitrogen supply system and then connected with a first material inlet at the lower part of the polymerization reactor through a pipeline; the polymerization reactor comprises a cylinder, a sealing head matched with the cylinder, a first overflow weir arranged on the cylinder and a stirring mechanism arranged at the bottom of the cylinder, the vaporized epoxide is diluted by nitrogen, the epoxide is mixed with materials by the stirring mechanism, and the nitrogen spontaneously moves, so that the mixing effect is further enhanced, the capacity of high heat and mass transfer rate is achieved, and the product quality of polyether polyol with high molecular weight and low unsaturation degree is improved.

Description

Reaction device for producing polyether polyol with low unsaturation degree

Technical Field

The utility model relates to a reaction unit for producing low unsaturation degree polyether polyol.

Background

Polyether polyol is commonly used for manufacturing general polyurethane foam plastics, adhesives, elastomers and the like, is a polymer with a main chain containing ether bonds, end groups or side groups containing a plurality of hydroxyl groups, and is prepared by ring-opening polymerization of micromolecular polyol, polyamine or a compound containing active hydrogen as an initiator and an epoxide under the action of a catalyst. Wherein, the catalyst is divided into strong base catalyst, amine catalyst, bimetallic catalyst and the like. The amine catalyst has limited catalytic capability and cannot catalyze and synthesize polyether polyol with large molecular weight. Strong base catalysts can produce higher molecular weight polyethers, the most common of which is potassium hydroxide, by a process that includes: preparing a potassium alkoxide catalytic system, carrying out polymerization reaction of epoxide, neutralizing, refining, filtering and the like; in addition to the problems of long production period, high energy consumption and large pollution, the method also has the problems of high unsaturation degree and reduced actual functionality caused by a plurality of side reactions.

The bimetallic catalyst is fully called as a bimetallic cyanide complex catalyst, has the advantages of high reaction speed, short production period, less side reactions, high catalytic activity and narrow molecular weight distribution, and can realize the industrial production of polyether polyol with high molecular weight and low unsaturation degree; however, because the reaction speed of the bimetallic catalyst is extremely high, the mass transfer capacity of equipment is extremely high under the condition of requiring narrow molecular weight distribution, and the full mixed flow kettle type reactor used in the production of general polyether is not suitable for the production of the bimetallic catalyst polyether polyol because the mass transfer rate is limited.

For example, patent publication No. CN109400867A proposes a reaction system and method for preparing polyether polyol. The reaction system comprises a reaction kettle main body and a static mixer, wherein a kettle top distributor and a kettle bottom liquid phase jet mixer are arranged in the reaction kettle, and Monel alloy mixed with 1-1000ppm of cerium oxide is preferably sprayed on the inner surface of the static mixer. By controlling the flow ratio of the kettle top distributor and the kettle bottom liquid phase jet mixer in the reaction process, the gas-liquid mixing effect is enhanced, the problems of more residual micromolecule substances, high unsaturation degree and wide molecular weight distribution in the product are solved, and the production safety is improved; for example, the patent of publication No. CN113332941A proposes an efficient multi-nozzle polyether polyol preparation device and process, which mainly adopts the premixing of epoxide and reaction liquid before entering the reactor and the mixing, atomizing and spraying mode of 4-6 sets of atomizing nozzles, to achieve the purpose of narrower molecular weight distribution and more homogeneous effect in the organic polymer synthesis production; the synthesis of high molecular weight polyether polyols using micromixers and microreactors is proposed as in patent publication No. CN 111925514A.

Most of the existing patents realize the mixing of epoxide and materials by spraying and arranging a distributor, but the spraying flow has higher energy consumption, polyether glycol catalyzed by a bimetallic catalyst basically only reacts in a liquid phase, the gas phase has few epoxide, the spraying of the circulating material is only beneficial to the mixing of the circulating material and materials in a kettle, and the mixing effect is still limited.

The control difficulty of the tubular reactor is high, the long reaction tube needs to be added with epoxide and a static mixer, the energy consumption is increased, and the occupied area of the equipment is large. The micromixer and the microreactor need higher operation pressure due to small volume, have limited production capacity, and cause reduction of mixing effect if equipment is enlarged, so that the development of a reactor with good mixing effect, high heat and mass transfer rate and high production efficiency is particularly important.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a reaction unit for producing low unsaturation polyether polyol is used for solving the problem that above-mentioned background art provided.

In order to solve the above problems, the utility model adopts the following technical scheme:

a reaction device for producing polyether polyol with low unsaturation degree comprises a polymerization reactor, a vaporizer, a nitrogen supply system and an initiation kettle, wherein an outlet of the vaporizer is connected with the nitrogen supply system and then connected with a first material inlet at the lower part of the polymerization reactor through a pipeline, a second material inlet at the lower part of the polymerization reactor is connected with the initiation kettle through a pipeline and a suction pump, and a material outlet is formed in the middle of the polymerization reactor;

the polymerization reactor comprises a cylinder body, a seal head matched with the cylinder body, a first overflow weir arranged on the cylinder body and a stirring mechanism arranged at the bottom of the cylinder body, wherein a dispersing assembly used for increasing the contact area of materials is further arranged at the bottom of the cylinder body, a heat exchange assembly is arranged at the upper end of the dispersing assembly, a packing layer is arranged at the upper end of the heat exchange assembly, and an air outlet is formed in the top end of the seal head.

As an implementation mode of the utility model, a circulation mechanism for recycling materials is further arranged on the polymerization reactor.

As an embodiment of the utility model, circulation mechanism includes nitrogen compressor, vapour and liquid separator and nitrogen gas cooler, head top gas outlet pass through the pipeline with the nitrogen gas cooler, the nitrogen gas cooler passes through the pipeline and is connected with the vapour and liquid separator air inlet, the vapour and liquid separator gas outlet passes through the pipeline and is connected with nitrogen compressor, nitrogen compressor passes through the pipeline and is connected with nitrogen gas supply system.

As an embodiment of the utility model, the dispersion subassembly is including setting up the ring canal distributor of bottom in the barrel and setting up the closing plate in ring canal distributor below, the entry and the material entry one of ring canal distributor are connected, the export of ring canal distributor to the closing plate sets up in opposite directions.

As an embodiment of the utility model, the dispersion subassembly is including setting up the sieve of bottom in the barrel, the sieve sets up between material inlet one and material inlet two.

As an implementation mode of the utility model, the barrel top still is provided with the second overflow weir, the height that highly is higher than first overflow weir of second overflow weir.

As an embodiment of the utility model, the percent opening of ring canal distributor is 0.02% ~ 1.2%.

As an embodiment of the utility model, the diameter of head is 1.5~4 times of barrel diameter.

As an implementation mode of the utility model, the total height of the end socket is 3-10 m.

As an embodiment of the utility model, it is a plurality of reaction unit's material export is passed through pipeline and circulating pump and is connected with next a set of reaction unit's material entry two.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:

the utility model discloses utilize nitrogen gas to dilute the epoxide concentration after the vaporization, and mix epoxide and material through rabbling mechanism to and nitrogen gas spontaneous motion, further strengthen the mixed effect, in order to reach the ability that heat and mass transfer rate is high, improve the product quality of high molecular weight, low unsaturation degree polyether glycol; the first overflow weir is arranged on the cylinder body, so that nitrogen can be separated out naturally, the influence on the quality of products is avoided, and the production efficiency is improved; the packing layer is arranged in the reactor to increase the contact area of gas and liquid, so that the reaction is more sufficient.

Drawings

Fig. 1 is a process flow diagram of example 1 of the present invention.

FIG. 2 is a schematic view of a polymerization reactor according to example 1 of the present invention.

FIG. 3 is a schematic view of a polymerization reactor according to example 2 of the present invention.

Figure 4 is a process flow diagram of the embodiment 3 of the present invention comprising four sets of reaction devices connected in series.

Wherein: the device comprises a polymerization reactor 1, a cylinder 1-1, a sealing head 1-2, a first overflow weir 1-3, a 2-initiation kettle, a vaporizer 3, a nitrogen compressor 4, a gas-liquid separator 5, a nitrogen cooler 6, a gas outlet 7, a demister 8, a second overflow weir 9, a material outlet 10, a packing layer 11, a heat exchange coil outlet 13, a heat exchange assembly 14, a heat exchange coil inlet 15, a material inlet II 16, a material inlet I17, a stirring mechanism 18, a ring pipe distributor 19, a sealing plate 20, a sealing sleeve 21, a sieve plate 22, a funnel 23, a 24-shaped circulating pump and a 25-extraction pump.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the following description of the present invention with reference to specific embodiments is given for clarity and completeness.

Example 1

As shown in fig. 1 to 3, a reaction device for producing polyether polyol with low unsaturation degree comprises a polymerization reactor 1, a vaporizer 3, a nitrogen supply system and an initiation kettle 2, wherein an outlet of the vaporizer 3 is connected with the nitrogen supply system and then connected with a first material inlet 17 at the lower part of the polymerization reactor 1 through a pipeline, a second material inlet 16 at the lower part of the polymerization reactor 1 is connected with the initiation kettle 2 through a pipeline and an extraction pump 25, and a material outlet 10 is arranged in the middle of the polymerization reactor 1. In this embodiment, the nitrogen supply system and the epoxy compound vaporized by the vaporizer 3 are introduced into the polymerization reactor 1 through the first material inlet 17, the polyether 204, the catalyst, the acidifying agent, and the like are added into the initiation tank 2, and the mixture is pumped into the polymerization reactor 1 through the second material inlet 16, and after the internal reaction, the obtained polyether polyol is discharged through the second material outlet 10.

As shown in fig. 2, the polymerization reactor 1 comprises a cylinder 1-1, a head 1-2 adapted to the cylinder 1-1, a first overflow weir 1-3 disposed on the cylinder 1-1, and a stirring mechanism 18 disposed at the bottom of the cylinder 1-1, the bottom of the cylinder 1-1 is further provided with a dispersion assembly for increasing the contact area of the materials, the upper end of the dispersion assembly is provided with a heat exchange assembly 14, the upper end of the heat exchange assembly 14 is provided with a packing layer 11, and the top of the head 1-2 is provided with an air outlet 7. Specifically, the cylinder body 1-1 extends into the end socket 1-2, so that the cylinder body 1-1 is higher than a part of the end socket 1-2, and a demister 8 is arranged at the upper part of the end socket 1-2 and used for removing small liquid drops carried in nitrogen.

The utility model discloses an utilize nitrogen gas to dilute the epoxy compound concentration after the vaporization, then pump epoxy compound and initiation cauldron 2 into through rabbling mechanism 18 the stirring such as catalyst in the polymerization reactor 1 is even, further strengthen the mixing effect, in order to reach good mass transfer ability, improve the product quality of high molecular weight, low unsaturation degree polyether glycol, reduce a large amount of heats that produces in the polymerization reactor 1 through setting up heat exchange assemblies 14, in order to reach the effect of convenient control temperature, through set up first overflow weir 1-3 on barrel 1-1, can let the better natural separation of nitrogen gas that does not participate in the reaction, thereby avoid influencing the quality of product, the polyether glycol that obtains after the intensive mixing reaction overflows barrel 1-1, discharge from material outlet 10, through set up packing layer 11 in barrel 1-1, the packing layer 11 is filled when equipment is installed, the type and the amount of the packing are provided by process design, and the packing layer does not need to be replaced except for overhauling, maintenance and reconstruction after being filled.

In the present embodiment, the stirring mechanism 18 is a conventional one, and will not be described here, as long as stirring and mixing are achieved. The utility model discloses in, the hoop that the material formed flows the stirring rake rotation opposite direction on direction and the rabbling mechanism 18, improves the stirring effect, makes the material mix more evenly.

Specifically, as shown in fig. 2, the heat exchange assembly 14 is a heat exchange coil in this embodiment, the heat exchange coil is disposed in the cylinder 1-1, and certainly, the heat exchange coil inlet 15 and the heat exchange coil outlet 13 penetrate through the cylinder 1-1 to the outside of the body, and condensed water is introduced into the heat exchange coil to achieve the effect of cooling.

As shown in fig. 1, the polymerization reactor 1 is further provided with a circulation mechanism for recycling materials. Specifically, the circulation mechanism includes nitrogen compressor 4, vapour and liquid separator 5 and nitrogen gas cooler 6, the gas outlet 7 on head 1-2 top pass through the pipeline with nitrogen gas cooler 6, nitrogen gas cooler 6 passes through the pipeline and is connected with 5 air inlets of vapour and liquid separator, 5 gas outlets of vapour and liquid separator pass through the pipeline and are connected with nitrogen compressor 4, nitrogen gas compressor 4 passes through the pipeline and is connected with nitrogen gas supply system, in this embodiment, 5 bottoms of vapour and liquid separator are provided with the leakage fluid dram for with the liquid discharge of gas-liquid separation. By arranging the circulating mechanism, unreacted epoxide and nitrogen can be recycled, and energy is saved.

As shown in fig. 2, the dispersion assembly includes a loop pipe distributor 19 disposed at the inner bottom of the cylinder 1-1 and a sealing plate 20 disposed below the loop pipe distributor 19, wherein an inlet of the loop pipe distributor 19 is connected to the first material inlet 17, and an outlet of the loop pipe distributor 19 is disposed opposite to the sealing plate 20. In this embodiment, the ring pipe distributor 19 is arranged to disperse the pumped materials through the small holes on the ring pipe distributor 19, so as to increase the contact area between the materials. Specifically, the outlet of the ring pipe distributor 19 is arranged downwards, the opening rate of the ring pipe distributor 19 is 0.02% -1.2%, and the smaller the opening pore diameter of the opening on the ring pipe distributor 19 is, the more the opening is, and the best effect is achieved. By providing the sealing plate 20, material can be prevented from being stored between the bottom of the cylinder 1-1 and the ring pipe distributor 19.

As shown in FIG. 2, the top of the barrel 1-1 is further provided with a second overflow weir 9, the height of the second overflow weir 9 is higher than that of the first overflow weir 1-3, and the diameter of the first overflow weir 1-3 is larger than that of the second overflow weir 9. in this embodiment, the second overflow weir 9 is provided to maintain the liquid level obtained after the reaction.

As shown in fig. 2, the joint between the end socket 1-2 and the cylinder 1-1 is funnel-shaped 23, so that a conical cavity is formed by the connection between the outer wall of the cylinder 1-1 and the inner wall of the end socket 1-2, and of course, the material outlet 10 is arranged at the bottom of the conical cavity, so as to completely discharge the solution obtained by the reaction.

In the embodiment, the total height of the end socket 1-2 is 3-10m, the diameter of the end socket 1-2 is 1.5-4 times of that of the cylinder 1-1, the number of the second material inlets 16 is 1-5, and in the embodiment, the number of the second material inlets 16 is 1. The above-described embodiment 1 may be used intermittently when used.

In the utility model, the polymerization reactor 1 is divided according to functionality, each component in the cylinder 1-1 forms a reaction section, the upper part of the end socket 1-2 is an expansion section, and the lower part of the end socket 1-2, namely the joint with the cylinder 1-1, is called a transition section; the diameter of the end socket 1-2 is larger than that of the cylinder 1-1, namely the diameter of the expanding section is larger than that of the reaction section; the reaction section is used for realizing the full mixing and reaction of materials, and the expansion section is mainly used for realizing the separation of liquid materials and gaseous materials; in the present invention, the part from the packing layer 11 to the second overflow weir 9 is to make the reaction more sufficient, and the actual reaction area is enlarged, which is the extension of the reaction section to the inside of the enlargement section; and the transition section is used for connecting the end socket 1-2 and the cylinder body 1-1.

Example 2

As shown in fig. 3, the present embodiment 2 is different from embodiment 1 in that the dispersing assembly includes a sieve plate 22 disposed at the bottom in the cylinder 1-1, and the sieve plate 22 is disposed between the first material inlet 17 and the second material inlet 16. In this embodiment 2, the bottom of the cylinder 1-1 is set to be a conical structure, so that the materials can be mixed more uniformly, the sieve plate 22 is arranged to enable gas to play a pre-dispersing role, the liquid obtained after the reaction can not leak, the aperture of the sieve plate 22 is not too large, and only the liquid can not fall down. The embodiment 2 can be used intermittently when in use.

Example 3

As shown in fig. 4, the material outlets 10 of a plurality of the reaction devices are connected with the material inlet two 16 of the next group of reaction devices through a pipeline and a circulating pump 24, and in this embodiment 3, the material can be continuously used, and only the embodiment 1 or the embodiment 2 needs to be connected in series.

In this example 3, 8000 molecular weight polyether with low unsaturation degree was prepared by connecting four reaction devices (example 1 or example 2) in series.

Four groups of reaction devices are connected in series, initiator 204 polyether (2 functionality 400 molecular weight), catalyst and acidifier are added into an initiation kettle 2, a small amount of epoxide is added for initiation reaction after nitrogen displacement and dehydration, and the mixture is pumped into a polymerization reactor 1 after the initiation is successful. In this example, the acidifying agent is concentrated sulfuric acid, the epoxide is propylene oxide, and the catalyst is a double metal cyanide complex catalyst (the process conditions for synthesizing polyether by double metal catalyst are well established in industry and are not shown here).

A first set of reaction apparatus: the nitrogen and the epoxide are preheated, vaporized and mixed, enter the bottom of the polymerization reactor 1, enter the middle part of the cylinder 1-1 after being distributed by the sieve plate 22, and are mixed with the initiator entering the bottom mixing zone through 4 tangential material inlets II 16, the molar ratio of the nitrogen to the epoxide is 1:1, the mass flow ratio of the epoxide to the initiator is 2:1, and the empty tower liquid velocity of the initiator is 0.2 m/s. The polyether after the reaction is pumped into a polymerization reactor 1 in the next group of reaction devices by a pump.

A second group of reaction devices: the nitrogen and the epoxide are preheated, vaporized and mixed, enter the bottom of the polymerization reactor 1 of the group, enter the middle part of the cylinder body 1-1 after being distributed by the sieve plate 22, and are mixed with the polyether entering the bottom mixing zone through the 4 tangential material inlets II 16, the molar ratio of the nitrogen to the epoxide is 1:1, the mass flow ratio of the epoxide to the polyether is 1.5:1, and the empty tower liquid velocity of the initiator is 0.2 m/s. The polyether after the reaction is pumped into a polymerization reactor 1 in the next group of reaction devices by a pump.

A third set of reaction apparatus: the nitrogen and the epoxide are preheated, vaporized and mixed, enter the bottom of the polymerization reactor 1 of the group, enter the middle part of the cylinder 1-1 after being distributed by the sieve plate 22, and are mixed with the polyether entering the bottom mixing zone through 4 tangential material inlets II 16, the molar ratio of the nitrogen to the epoxide is 1:1, the molar flow ratio of the epoxide to the polyether is 0.8:1, and the empty tower liquid velocity of the initiator is 0.2 m/s. The polyether after the reaction is pumped into a polymerization reactor 1 in the next group of reaction devices by a pump.

Fourth group reaction unit: the nitrogen and the epoxide are preheated, vaporized and mixed, enter the bottom of the polymerization reactor 1 of the group, enter the middle part of the cylinder body 1-1 after being distributed by the sieve plate 22, and are mixed with the polyether entering the bottom mixing zone through the 4 tangential material inlets II 16, the molar ratio of the nitrogen to the epoxide is 1:1, the molar flow ratio of the epoxide to the polyether is 0.5:1, and the empty tower liquid velocity of the initiator is 0.2 m/s. And pumping the polyether after the reaction into a degassing kettle by a pump, and performing vacuum degassing to enter a finished product tank.

The average molecular weight of the finally obtained product is 8092, the viscosity is 2960, the degree of unsaturation is 0.004, and the polydispersity of a GPC chart is 1.0065.

Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art may still modify the technical solutions described in the foregoing embodiments, or may substitute some technical features of the foregoing embodiments; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present invention.

Claims (10)

1. A reaction apparatus for producing a low unsaturation polyether polyol, characterized by: the device comprises a polymerization reactor, a vaporizer, a nitrogen supply system and an initiation kettle, wherein an outlet of the vaporizer is connected with the nitrogen supply system and then connected with a first material inlet at the lower part of the polymerization reactor through a pipeline, a second material inlet at the lower part of the polymerization reactor is connected with the initiation kettle through a pipeline and an extraction pump, and a material outlet is arranged in the middle of the polymerization reactor;

including the barrel, with the head of barrel looks adaptation, set up first overflow weir and the setting on the barrel in the polymerization reactor be in the rabbling mechanism of barrel bottom, the bottom still is provided with the dispersion subassembly that is used for making material increase area of contact in the barrel, dispersion subassembly upper end is provided with heat exchange assemblies, the heat exchange assemblies upper end is provided with the packing layer, the head top is provided with the gas outlet.

2. A reaction device for the production of a low unsaturation polyether polyol according to claim 1 wherein: the polymerization reactor is also provided with a circulating mechanism for recycling materials.

3. A reaction device for the production of a low unsaturation polyether polyol according to claim 2 wherein: circulation mechanism includes nitrogen compressor, vapour and liquid separator and nitrogen gas cooler, head top gas outlet pass through the pipeline with the nitrogen gas cooler, the nitrogen gas cooler passes through the pipeline and is connected with vapour and liquid separator air inlet, the vapour and liquid separator gas outlet passes through the pipeline and is connected with the nitrogen compressor, the nitrogen compressor passes through the pipeline and is connected with nitrogen gas supply system.

4. A reaction unit for the production of polyether polyols with low unsaturation according to claim 1, characterized in that: the dispersing assembly comprises a ring pipe distributor arranged at the bottom in the barrel and a sealing plate arranged below the ring pipe distributor, the inlet of the ring pipe distributor is connected with the material inlet I, and the outlet of the ring pipe distributor is oppositely arranged to the sealing plate.

5. A reaction device for the production of a low unsaturation polyether polyol according to claim 1 wherein: the dispersing component comprises a sieve plate arranged at the bottom in the cylinder body, and the sieve plate is arranged between a first material inlet and a second material inlet.

6. A reaction device for the production of a low unsaturation polyether polyol according to claim 1 wherein: the top end of the cylinder body is also provided with a second overflow weir, and the height of the second overflow weir is higher than that of the first overflow weir.

7. A reaction unit for the production of polyether polyols having a low degree of unsaturation according to claim 4 wherein: the hole opening rate of the ring pipe distributor is 0.02% -1.2%.

8. A reaction unit for the production of polyether polyols with low unsaturation according to claim 1, characterized in that: the diameter of the seal head is 1.5-4 times of the diameter of the cylinder.

9. A reaction device for the production of a low unsaturation polyether polyol according to claim 1 wherein: the total height of the end socket is 3-10 m.

10. A reaction device for the production of polyether polyols with low unsaturation according to any of claims 1-9 wherein: and the material outlets of the reaction devices are connected with the material inlet II of the next group of reaction devices through a pipeline and a circulating pump.

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