Evaporative crystallization device and method for poly (2-vinylpyridine)

Abstract

The invention relates to the field of separation, in particular to a poly (2-vinylpyridine) evaporative crystallization device and method.The poly (2-vinylpyridine) evaporative crystallization device comprises a reaction kettle, and an evaporative crystallization assembly for conducting evaporative crystallization treatment on poly (2-vinylpyridine) is arranged in the reaction kettle; through cooperation of the reaction kettle, the pretreater and the separator, the evaporative crystallization extraction effect on the organic phase in the poly (2-vinylpyridine) kettle residue is achieved, a high-value picolinic acid product is prepared, economic benefits are improved while waste is avoided, the economic benefits are guaranteed, and the production cost is reduced. And carbon emission reduction is realized, and the concept of green sustainable development is met.

Description

Technical Field

[0001] The present invention relates to the field of separation, and particularly to a poly-2-vinylpyridine evaporation crystallization device and method. Background Art

[0002] In the process of preparing 2-vinylpyridine, it is usually necessary to heat and distill the mother liquor containing 2-vinylpyridine under alkaline conditions to obtain a separated and purified 2-vinylpyridine product. During the reaction process, alkaline polymer residues will inevitably be generated at the bottom of the evaporation kettle. The main component of the organic phase of the residues is complex pyridine macromolecular derivatives (mostly poly-2-vinylpyridine polymers and by-products), similar to asphaltene, which has high calorific value, high toxicity, strong corrosiveness, complex components, and no clear end use, and can only be disposed of as hazardous waste. This is an urgent technical problem to be solved in the current process of preparing 2-vinylpyridine products.

[0003] If the residues can be recycled, not only the reduction of hazardous waste can be achieved, the hazardous waste disposal cost can be reduced, and the cost of the main product can be lowered. At the same time, the potassium salts and pyridine derivatives recovered by resource recycling can be used as by-products to achieve additional efficiency. While ensuring economic benefits, carbon emission reduction is also achieved, which is in line with the concept of green sustainable development.

[0004] Therefore, in view of the above statements, there is still room for optimization in the existing methods for treating the residues of poly-2-vinylpyridine. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a poly-2-vinylpyridine evaporation crystallization device, including a reaction kettle, and an evaporation crystallization component for performing evaporation crystallization treatment on poly-vinylpyridine is arranged in the reaction kettle. The evaporation crystallization component includes: A partition ring plate, which is limited in the reaction kettle to divide the reaction kettle into an evaporation chamber and a crystallization chamber up and down.

[0006] A storage cylinder, which is arranged on the upper side of the reaction kettle and is connected to the reaction kettle in a communicating manner. A pre-processor is jointly arranged between the storage cylinder and the reaction kettle.

[0007] A connecting ring sleeve, which is limited in the reaction kettle and located above the partition ring plate. A separator is jointly arranged between the connecting ring sleeve and the partition ring plate.

[0008] Preferably, the pre-processor includes two annular gas pipes limited at intervals in the storage cylinder. A plurality of air guide pipes are circumferentially and uniformly communicated between the two annular gas pipes, and the plurality of air guide pipes extend downward and penetrate into the evaporation chamber.

[0009] Preferably, a plurality of connecting conduits passing through the reaction kettle are circumferentially and uniformly connected to the connecting ring sleeve. A connecting ring pipe is jointly connected between all the connecting conduits, and a plurality of sinking air pipes are circumferentially communicated with the connecting ring pipe.

[0010] Preferably, a plurality of communication ports are provided on the lower side of the storage cylinder, and a closed blocking block is correspondingly connected at the communication ports.

[0011] Preferably, the diameters of the communication ports are distributed in a stepped manner. The closed blocking block extends downward corresponding to the communication ports with an extension connecting rod, and the lower side of the extension connecting rod is connected with a mounting frame which is limitedly penetrated through the reaction kettle.

[0012] Preferably, one side of all the mounting frames passing through the reaction kettle abuts against the outer edge of the storage cylinder together.

[0013] Preferably, the separator includes a driving rotating rod penetrating through a partition ring plate, and a stirring frame located in the evaporation cavity is limitedly connected on the driving rotating rod.

[0014] Preferably, a plurality of discharge ports are circumferentially and uniformly arranged on the connecting ring sleeve, and a filter hole plate is jointly and limitedly connected between the driving rotating rod and the connecting ring sleeve.

[0015] Preferably, a sliding floating plate is sleeved outside the driving rotating rod, and a connecting sliding sleeve sleeved on the driving rotating rod is jointly connected between the sliding floating plate and the filter hole plate, and the connecting sliding sleeve penetrates through the partition ring plate.

[0016] In addition, the present invention also provides a method for evaporating and crystallizing poly-2-vinylpyridine, comprising the following steps: S1: The dehydrated and evaporated alkaline kettle residue from the vinylpyridine production line is mixed with deionized water for dilution. The diluted organic phase mixture is pre-introduced into the storage cylinder for temporary storage, and a nitric acid solution is injected into the evaporation cavity in the reaction kettle for reaction.

[0017] S2: The nitric acid solution in the reaction kettle is heated and temperature is raised. Meanwhile, the gas in the evaporation cavity is extracted through a pre-processor to form a micro-vacuum environment to avoid deflagration, and the hot air flow during the extraction process is driven to pass through the storage cylinder to preheat the organic phase mixture in the storage cylinder.

[0018] S3: The preheated organic phase mixture is injected into the evaporation cavity to carry out an oxidation reaction with the nitric acid solution. During the reaction process, the temperature in the reaction kettle rises, the nitric acid solution evaporates, is discharged through a connecting conduit and condensed to recover the nitric acid solution, the reaction crystallization of the nitric acid solution and the organic phase mixture is accelerated by mechanical induction, and the centrifugal force is used to separate the precipitated picolinic acid nitrate crystals from the reaction solution.

[0019] S4: The separated crystals precipitated in the evaporation chamber are introduced into the crystallization chamber, and an alkaline lye aqueous phase is injected into the crystallization chamber to further separate and purify the organic phase crystals and neutralize the reaction solution. Then, the neutralized solution is subjected to secondary evaporation crystallization in the crystallization chamber to obtain granular potassium nitrate. Finally, the mother liquor in the crystallization chamber is evaporated to dryness, and the obtained solid mixture is rinsed with absolute ethanol, and the solid is dried to obtain a powdered potassium nitrate product, and the pyridinecarboxylic acid product is obtained by evaporating and crystallizing the ethanol solution.

[0020] In summary, the present application includes at least one of the following beneficial technical effects: First, through the cooperation among the reaction kettle, the pre-processor and the separator, the present invention realizes the evaporation crystallization extraction effect of the organic phase in the residue of poly-2-vinylpyridine kettle, prepares a high-value pyridinecarboxylic acid product, improves the economic benefit while avoiding waste, and realizes carbon emission reduction while ensuring the economic benefit, which is in line with the concept of green and sustainable development.

[0021] Second, through the mutual cooperation between the pre-processor and the separator, while evacuating the reaction kettle, the organic phase mixture and the nitric acid solution are preheated, avoiding the generation of safety risks and increasing the efficiency of evaporating and separating the organic phase in the kettle residue.

[0022] Third, through the mutual cooperation among the driving rotating shaft, the stirring frame and the filtering orifice plate, while promoting the precipitation of the reaction solution crystals in the evaporation chamber, a certain centrifugal force is applied to separate the precipitated crystals from the evaporation chamber, effectively improving the efficiency of evaporating and crystallizing and separating the reaction solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the drawings and embodiments.

[0024] Figure 1 is a schematic structural diagram of the present invention.

[0025] Figure 2 is a schematic structural diagram of the evaporation crystallization assembly of the present invention.

[0026] Figure 3 is a schematic structural diagram of the pre-processor of the present invention.

[0027] Figure 4 is a schematic structural diagram of the annular air pipe of the present invention.

[0028] Figure 5 is the present invention Figure 4 magnified view of A in.

[0029] Figure 6 is a schematic structural diagram of the separator of the present invention.

[0030] Figure 7It is a schematic structural diagram of the filter orifice plate of the present invention.

[0031] Figure 8 It is the present invention Figure 7 An enlarged view of B in it.

[0032] In the figure, 1 is a reaction kettle; 100 is an evaporation chamber; 101 is a crystallization chamber; 2 is an evaporation and crystallization assembly; 20 is a partition ring plate; 200 is an opening; 21 is a storage cylinder; 22 is a pre-processor; 220 is an annular air pipe; 221 is a guide air pipe; 222 is a connecting catheter; 223 is a connecting ring pipe; 224 is a sinking air pipe; 225 is a communication port; 226 is a closing block; 227 is an extension connecting rod; 228 is a mounting frame; 229 is a pressing spring; 23 is a connecting ring sleeve; 230 is a discharge port; 24 is a separator; 240 is a driving rotating rod; 241 is a stirring frame; 242 is a filter orifice plate; 243 is a sliding floating plate; 244 is a connecting sliding sleeve; 245 is a filling pipeline; 25 is a limiting guide rod; 250 is a stop hole. Specific embodiments

[0033] The following will be described in detail with reference to the appended Figure 1 to the appended Figure 8 embodiments of the present invention.

[0034] The embodiment of the present application discloses a poly-2-vinylpyridine evaporation and crystallization device and method. The present application is mainly applied in the process of treating the kettle residue generated in the preparation of 2-vinylpyridine. In terms of technical effects, the organic phase (poly-2-vinylpyridine polymer) in the kettle residue is subjected to evaporation and crystallization treatment to realize the resource recovery and utilization of the kettle residue; especially in the process of evaporation and crystallization treatment of poly-2-vinylpyridine, through the pretreatment of the organic phase mixture and nitric acid solution, the efficiency of evaporation and crystallization of the poly-2-vinylpyridine polymer is effectively increased; and, the present application also realizes the precipitation of the crystallization of the reaction liquid in the evaporation chamber by the mutual cooperation between the driving rotating shaft, the stirring frame and the filter orifice plate, and at the same time, applies a certain centrifugal force to separate the precipitated crystallization from the evaporation chamber, effectively improving the efficiency of evaporation and crystallization separation of the reaction liquid.

[0035] Example 1: Refer to Figure 1 As shown, a poly-2-vinylpyridine evaporation and crystallization device includes a reaction kettle 1. The reaction kettle 1 is internally provided with a heating element (not shown in the figure) to provide the temperature environment required in the treatment process. An evaporation and crystallization assembly 2 for evaporation and crystallization treatment of poly-2-vinylpyridine is provided in the reaction kettle 1.

[0036] In use, the dehydrated and evaporated alkaline kettle residue from the vinylpyridine production line is mixed with deionized water. The high-concentration potassium hydroxide in the kettle residue dissolves in water to form an alkaline solution. The organic phase (pyridine derivatives) in the kettle residue is insoluble in the alkali, forming a liquid-liquid two-phase system that naturally separates. The organic phase with a lower density floats on the upper layer. Through liquid-liquid separation, the organic phase (mainly poly-2-vinylpyridine polymer) and the alkaline solution aqueous phase (potassium hydroxide) are obtained respectively. The diluted organic phase mixture and the nitric acid solution are respectively injected into the reaction kettle 1 for mixing and oxidation reaction. The organic phase mixture is subjected to evaporation crystallization treatment through the evaporation crystallization assembly 2 to obtain an evaporation-concentrated crystallization product, and then through filtration and drying, picolinic acid products are obtained, realizing the evaporation crystallization treatment of the poly-2-vinylpyridine mixture and the resource recovery and utilization of the kettle residue.

[0037] Refer to Figures 1 to 3 As shown, that is, the evaporation crystallization assembly 2 for performing evaporation crystallization treatment on poly-2-vinylpyridine; specifically, the evaporation crystallization assembly 2 includes: A partition ring plate 20 is limited in the reaction kettle 1 to divide the reaction kettle 1 into an evaporation chamber 100 and a crystallization chamber 101 up and down.

[0038] A storage cylinder 21 is penetrated through the upper side of the reaction kettle 1 and is communicatively connected to the reaction kettle 1. A pre-processor 22 is jointly arranged between the storage cylinder 21 and the reaction kettle 1.

[0039] A connecting ring sleeve 23 is limited in the reaction kettle 1 and is located above the partition ring plate 20. A separator 24 is jointly arranged between the connecting ring sleeve 23 and the partition ring plate 20.

[0040] Refer to Figures 2 to 4 As shown, before injecting the organic phase mixture and nitric acid into the reaction kettle 1 for reaction respectively, due to the strong oxidizing property of nitric acid itself, a large amount of heat and gas will be released during its reaction with the organic phase mixture. And oxygen in the air is an oxidant that can accelerate the oxidation reaction. When there is air in the reaction kettle 1, oxygen will react with nitric acid and organic matter to generate more oxidation products and heat, making the reaction more intense and increasing the risk of deflagration. Therefore, in order to avoid the problems caused by deflagration, a pre-processor 22 for extracting the excess gas in the reaction kettle 1 is set. Specifically, the pre-processor 22 includes two annular gas pipes 220 that are spaced and limited in the storage cylinder 21. A plurality of guide gas pipes 221 are circumferentially and uniformly communicated between the two annular gas pipes 220. The plurality of guide gas pipes 221 extend downward into the evaporation chamber 100 to extract the excess gas in the reaction kettle 1 at the initial stage, so that the nitric acid and the organic phase mixture react under a micro-vacuum condition, effectively avoiding the generation of deflagration problems. In order to provide the negative pressure suction required for extracting gas, an air pump (not shown in the figure) limited on the storage cylinder 21 is also externally connected to one of the upper annular gas pipes 220.

[0041] Furthermore, since the oxidation reaction of the mixed solution of nitric acid and the organic phase usually requires certain temperature-raising conditions, in the initial state, the nitric acid solution is first injected into the connection ring sleeve 23 in the evaporation chamber 100 for preheating treatment. At the same time, the heated gas in the evaporation chamber 100 is extracted through an air pump, two annular gas pipes 220 and a plurality of gas guide pipes 221. Since heat always transfers from a high-temperature area to a low-temperature area, after the heated gas is extracted through the gas guide pipes 221 and the annular gas pipes 220, its heat is transferred to the organic phase mixed solution in the storage cylinder 21, forming a preheating effect on the organic phase mixed solution in the storage cylinder 21 to improve the efficiency of subsequent oxidation reaction and evaporation crystallization.

[0042] Refer to Figure 2 and Figure 3 As shown, the preheated organic phase solution is injected into the evaporation chamber 100 to carry out an oxygenation reaction with the nitric acid solution. After the reaction is completed, the temperature inside the reaction kettle 1 is raised by a heating element to form a distillation effect on the oxidation synthesis reaction solution, and the unreacted nitric acid in the reaction solution is distilled out. At this time, in order to guide and discharge the nitric acid vapor for condensation, a connection conduit 222 passing through the reaction kettle 1 is circumferentially and uniformly connected to the connection ring sleeve 23. The connection conduit 222 is preferably made of a heat-insulating material to prevent the high temperature in the reaction kettle 1 from being transferred to the connection conduit 222. One ends of all the connection conduits 222 outside the reaction kettle 1 are commonly connected to a connection ring pipe 223. A plurality of downward gas pipes 224 are circumferentially communicated with the connection ring pipe 223. The connection ring pipe 223 and the downward gas pipes 224 are preferably made of a heat-conducting material to improve the heat exchange rate between the connection ring pipe 223 and the outside world and enhance the condensation effect on the nitric acid vapor.

[0043] Furthermore, after the nitric acid vapor is discharged outward through a plurality of connection conduits 222 and introduced into the connection ring pipe 223, the high heat of the nitric acid vapor exchanges heat with the outside air through the connection ring pipe 223, causing the high-temperature nitric acid vapor to condense and then fall into a plurality of downward gas pipes 224 for accumulation to re-form a nitric acid solution.

[0044] It should be noted that during the oxidation synthesis reaction of nitric acid and the organic phase solution, as the reaction progresses, a part of nitrogen oxide (such as nitric oxide, nitrogen dioxide, etc.) tail gas will be gradually generated during the reaction process, and it is also introduced into the connection ring pipe 223 and the downward gas pipes 224 through a plurality of connection conduits 222. At this time, the nitric acid solution in the downward gas pipes 224 is used to absorb the nitrogen oxide tail gas for the subsequent recycling of the nitric acid solution.

[0045] At the same time, during the overall treatment process, the micro-negative pressure state inside the reaction kettle 1 needs to be maintained all the time.

[0046] Refer to Figures 3 to 5As shown, in the initial state, since it is necessary to evacuate the reaction kettle 1, in order to control the organic phase mixture in the storage cylinder 21 to fall into the reaction kettle 1 to contact the nitric acid solution, and at the same time to preheat the organic phase solution, a number of communication ports 225 are provided on the lower side of the storage cylinder 21 and are connected to the evaporation chamber 100, so as to introduce the organic phase mixture in the storage cylinder 21 into the evaporation chamber 100. A sealing block 226 is correspondingly connected at the communication port 225 for controlling the falling of the organic phase solution in the storage cylinder 21 to avoid the problem that the organic phase solution contacts the nitric acid solution in the evaporation chamber 100 in advance and is prone to deflagration.

[0047] Referring to Figures 3 to 5 As shown, the diameter of the communication port 225 is set with a stepped necking to limit the downward movement of the sealing block 226, thereby forming a sealing effect on the storage cylinder 21. The sealing block 226 extends downward corresponding to the communication port 225 with an extension link 227. The lower side of the extension link 227 is connected with a mounting frame 228 which is limited to penetrate through the reaction kettle 1. A pressing spring 229 is sleeved on the extension link 227 and is located between the mounting frame 228 and the storage cylinder 21.

[0048] In the initial state, the reaction kettle 1 and the external pressure are the same, and the pressing spring 229 is in a compressed and pressed state to provide a tendency for the storage cylinder 21 to always slide upward, so that the sealing block 226 is closely attached to the communication port 225, forming an initial sealing effect on the storage cylinder 21 to avoid the problem that the organic phase mixture falls into the evaporation chamber 100 after being injected into the storage cylinder 21.

[0049] During use, after evacuating the inside of the reaction kettle 1, the pressure inside the reaction kettle 1 decreases to form a pressure difference with the external atmospheric pressure. The external pressure difference drives the whole storage cylinder 21 to move downward, forming a relative position slip with the sealing block 226, so that the sealing block 226 is separated from the communication port 225, and at the same time drives the connected pressing spring 229 to be further compressed, so as to facilitate the preheated organic phase mixture in the storage cylinder 21 to fall into the reaction kettle 1.

[0050] It should be noted that although heating and temperature rising treatment are carried out while evacuating the inside of the reaction kettle 1, since high temperature will cause the nitric acid solution to pyrolyze in advance, the efficiency of the pressure rise in the reaction kettle 1 caused by heating in the initial state is less than the efficiency of reducing the pressure in the reaction kettle 1 by evacuating, that is, the pressure in the reaction kettle 1 is always less than the external atmospheric pressure in the evacuated state.

[0051] Referring to Figure 3 and Figure 4As shown, since it is necessary to drive the storage cylinder 21 to slide vertically, the installation frame 228 is arranged in a "C" shape. Its vertical section is limitedly connected to the reaction kettle 1, and one of the horizontal sections on its lower side is connected to the extension connecting rod 227. All the upper horizontal sections of the installation frame 228 jointly abut against the outer edge of the storage cylinder 21 to ensure the stability of the storage cylinder 21 during vertical sliding.

[0052] Refer to Figure 6 and Figure 7 As shown, the separator 24 includes a driving rotating rod 240 penetrating through the partition ring plate 20, and a stirring frame 241 located in the evaporation chamber 100 is limitedly connected to the driving rotating rod 240. During use, the driving rotating rod 240 is driven to rotate by the existing motor driving technology. The rotation of the driving rotating rod 240 drives the stirring frame 241 to rotate synchronously, so that the stirring frame 241 drives the oxidation synthesis reaction liquid (nitric acid solution and organic phase mixture) in the evaporation chamber 100 to rotate and shift. In the initial stage of the reaction between the nitric acid solution and the organic phase mixture in the evaporation chamber 100, through the rotation of the stirring frame 241, the reaction between the nitric acid solution and the organic phase mixture is accelerated to crystallize (pyridinecarboxylic acid nitrate crystallization). In the middle and late stages of the oxygenation reaction, centrifugal force is applied to the reaction liquid by the rotation of the stirring frame 241 to promote the separation of the precipitated crystals from the reaction liquid.

[0053] In order to discharge the filtrate after discharging the crystals, a drain pipe penetrates through the connecting sleeve and the reaction kettle 1 together, and the drain pipe is in a normally closed state.

[0054] Furthermore, refer to Figure 2 、 Figure 6 and Figure 7 As shown, a plurality of discharge ports 230 are evenly formed in the circumferential direction on the connecting ring sleeve 23. A filter hole plate 242 is jointly and limitedly connected between the driving rotating rod 240 and the connecting ring sleeve 23 for filtering the crystals precipitated in the reaction liquid. An opening 200 is also formed on the partition ring plate 20 so that the precipitated crystals can fall into the crystal chamber 101. In the initial state, the filter hole plate 242 fits on the partition ring plate 20 (that is, at the bottom of the evaporation chamber 100).

[0055] During use, when it is necessary to separate the crystals in the evaporation chamber 100 from the reaction liquid, the filter hole plate 242 is driven to move upward. During the process of the filter hole plate 242 moving upward to a position flush with the discharge ports 230, the crystals mixed in the reaction liquid in the evaporation chamber 100 will be gradually driven to move upward. At this time, the centrifugal force applied by the rotation of the stirring frame 241 enables the precipitated crystals to break away from the filter hole plate 242 and be discharged from the evaporation chamber 100 through the discharge ports 230 to complete the separation effect of the crystals and the reaction liquid. At this time, the filtrate after discharging the crystals can be discharged through the drain pipe.

[0056] Even further, refer toFigure 6 and Figure 7 As shown in Figure 7 , in order to further process the crystals (pyridinecarboxylate nitrate crystals) precipitated from the oxidative synthesis reaction in the evaporation chamber 100, it is also necessary to introduce the alkaline aqueous phase after the initial liquid-liquid separation into the crystallization chamber 101 to carry out the neutralization reaction. At the same time, in order to drive the filter orifice plate 242 to move upward to complete the effect of separating the crystals precipitated in the evaporation chamber 100 from the reaction solution, a sliding floating plate 243 is sleeved outside the driving rod 240. A connecting sliding sleeve 244 sleeved on the driving rod 240 is commonly connected between the sliding floating plate 243 and the filter orifice plate 242. The connecting sliding sleeve 244 slidably penetrates through the partition ring plate 20. A filling pipeline 245 penetrating out of the reaction kettle 1 is communicated in the crystallization chamber 101. The filling pipeline 245 is preferably arranged on the lower side of the sliding floating plate 243.

[0057] During use, after the crystals are precipitated and separated in the evaporation chamber 100, the alkaline aqueous phase after the initial separation is injected into the crystallization chamber 101. As the alkaline aqueous phase is injected, the sliding floating plate 243 also floats upward. The upward floating of the sliding floating plate 243 drives the connecting sliding sleeve 244 and the filter orifice plate 242 to move upward synchronously to complete the effect of separating the crystals in the evaporation chamber 100 from the reaction solution.

[0058] After the crystals (pyridinecarboxylate nitrate crystals) in the evaporation chamber 100 fall into the crystallization chamber 101, they carry out a neutralization reaction with the alkaline aqueous phase. Then, nitric acid solution is injected into the crystallization chamber 101 to neutralize the alkaline aqueous phase to obtain a neutralized solution (mainly pyridinecarboxylic acid and potassium nitrate). The neutralized solution is heated to evaporate and concentrate to obtain granular potassium nitrate. Finally, the granular potassium nitrate is washed with absolute ethanol, filtered to obtain refined granular potassium nitrate, and dried to obtain granular potassium nitrate products, completing the resource recovery and utilization of the organic phase (poly-2-vinylpyridine polymer) in the kettle residue.

[0059] As an alternative embodiment, a stirring frame 241 located on the lower side of the sliding floating plate 243 can also be limited on the driving rod 240 to promote the precipitation effect of the crystals in the crystallization chamber 101. At the same time, in the initial state, a distance is provided between the sliding floating plate 243 and the bottom of the reaction kettle 1, so as to enable the sliding floating plate 243 to respond to the upward floating in time, so as to synchronously drive the connecting sliding sleeve 244 and the filter orifice plate 242 to move upward, and promote the separation of the precipitated crystals in the evaporation chamber 100 from the reaction solution.

[0060] Example 2: Refer to Figure 7 and Figure 8As shown in the figure, on the basis of the first embodiment, in order to improve the efficiency of discharging crystals from the evaporation chamber 100, at least one limiting guide rod 25 is provided under the lower side of the partition ring plate 20, and a stop hole 250 is correspondingly provided on the sliding floating plate 243 to cooperate with the limiting guide rod 25. In the initial state, the limiting guide rod 25 and the stop hole 250 are arranged at intervals and separated from each other. The height of the stirring frame 241 in the evaporation chamber 100 is preferably set to be flush with the discharge port 230.

[0061] During use, after injecting the alkaline aqueous phase into the crystallization chamber 101, the sliding floating plate 243 floating with the alkaline aqueous phase synchronously drives the connecting sliding sleeve 244 and the filter hole plate 242 to move upward synchronously, so that the stop hole 250 on the sliding floating plate 243 and the limiting guide rod 25 on the partition ring plate 20 form a relative position sliding effect. After the filter hole plate 242 moves upward and fits against the lower side of the stirring frame 241 in the evaporation chamber 100, at this time, the limiting guide rod 25 is correspondingly inserted into the stop hole 250 to limit the rotation of the connecting sliding sleeve 244, the sliding floating plate 243 and the filter hole plate 242, and avoid the rotation of the driving rotating rod 240 driving the filter hole plate 242 to rotate. The rotation of the driving rotating rod 240 will synchronously drive the stirring frame 241 to rotate, so that the stirring frame 241 in the evaporation chamber 100 rotates and slides relative to the filter hole plate 242. Thus, while applying a certain centrifugal force to the crystals on the filter hole plate 242 through the rotating stirring frame 241, the effect of scraping and pushing the crystals on the filter hole plate 242 is achieved, so as to achieve the effect of promoting the discharge efficiency of the crystals from the evaporation chamber 100.

[0062] In addition, the present invention also provides a method for evaporative crystallization of poly-2-vinylpyridine, including the following steps: S1: The dehydrated and evaporated alkaline kettle residue from the vinylpyridine production line is mixed with deionized water for dilution. The diluted organic phase mixture is pre-passed into the storage cylinder 21 for temporary storage, and a nitric acid solution is injected into the evaporation chamber 100 in the reaction kettle 1 for reaction.

[0063] S2: The nitric acid solution in the reaction kettle 1 is heated and raised in temperature. At the same time, the gas in the evaporation chamber 100 is extracted through the pre-processor 22 to form a micro-vacuum environment to avoid deflagration, and the hot air flow during the extraction process is driven to pass through the storage cylinder 21 to preheat the organic phase mixture in the storage cylinder 21.

[0064] S3: The preheated organic phase mixture is injected into the evaporation chamber 100 and undergoes an oxidation reaction with the nitric acid solution. During the reaction process, the temperature in the reaction kettle 1 rises, the nitric acid solution evaporates, is discharged through the connecting conduit 222 and condensed to recover the nitric acid solution. The reaction crystallization of the nitric acid solution and the organic phase mixture is accelerated by mechanical induction, and the precipitated picolinic acid nitrate crystals are separated from the reaction solution by using centrifugal force.

[0065] S4: The separated crystals precipitated in the evaporation chamber 100 are introduced into the crystallization chamber 101, and an alkaline aqueous solution is injected into the crystallization chamber 101 to further separate and purify the organic phase crystals and neutralize the reaction solution. Then, the neutralized solution is subjected to secondary evaporation crystallization in the crystallization chamber 101 to obtain granular potassium nitrate. Finally, the mother liquor in the crystallization chamber 101 is evaporated to dryness, the obtained solid mixture is rinsed with absolute ethanol, the solid is dried to obtain a potassium nitrate powder product, and the ethanol solution is evaporated and crystallized to obtain a picolinic acid product.

[0066] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting.

[0067] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A poly-2-vinylpyridine evaporation crystallization device, comprising a reaction kettle (1), characterized in that: An evaporation and crystallization assembly (2) for performing evaporation and crystallization treatment on poly-2-vinylpyridine is provided inside the described reactor (1). The evaporation and crystallization assembly (2) includes: A partition ring plate (20) is limited inside the reactor (1) to divide the reactor (1) vertically into an evaporation chamber (100) and a crystallization chamber (101); A storage cylinder (21) is penetrated through the upper side of the reactor (1) and is connected to the reactor (1) in a communicating manner. A pre-processor (22) is jointly provided between the storage cylinder (21) and the reactor (1); A connecting ring sleeve (23) is limited inside the reactor (1) and is located above the partition ring plate (20). A separator (24) is jointly provided between the connecting ring sleeve (23) and the partition ring plate (20).

2. The poly-2-vinylpyridine evaporation crystallization device according to claim 1, wherein: The described pre-processor (22) includes two annular gas pipes (220) that are spaced and limited inside the storage cylinder (21). A plurality of gas guide pipes (221) are circumferentially and uniformly communicated between the two annular gas pipes (220), and the plurality of gas guide pipes (221) extend downward and penetrate into the evaporation chamber (100).

3. The evaporation crystallization device of poly-2-vinylpyridine according to claim 2, characterized in that: Connecting conduits (222) that penetrate through the reactor (1) are circumferentially and uniformly connected to the connecting ring sleeve (23). A connecting ring pipe (223) is jointly connected between all the connecting conduits (222). A plurality of downward air pipes (224) are circumferentially communicated with the connecting ring pipe (223).

4. A poly-2-vinylpyridine evaporation crystallization device according to claim 1, characterized in that: A plurality of communication ports (225) are provided on the lower side of the storage cylinder (21), and a closed blocking block (226) is correspondingly connected at the communication ports (225).

5. A poly 2-vinylpyridine evaporation crystallization device according to claim 4, characterized in that: The caliber of the communication ports (225) is distributed in a stepped manner. The closed blocking block (226) extends downward corresponding to the communication ports (225) with an extension connecting rod (227), and the lower side of the extension connecting rod (227) is connected to a mounting frame (228) that is limited and penetrated through the reactor (1).

6. The evaporation crystallization device of poly-2-vinylpyridine according to claim 5, wherein: One side of all the mounting frames (228) that penetrates through the reactor (1) jointly abuts against the outer edge of the storage cylinder (21).

7. The evaporation crystallization device for poly-2-vinylpyridine according to claim 1, characterized in that: The described separator (24) includes a driving rotating rod (240) that is penetrated through the partition ring plate (20), and a stirring frame (241) that is limited and connected to the driving rotating rod (240) and is located inside the evaporation chamber (100).

8. A poly-2-vinylpyridine evaporation crystallization device according to claim 1, characterized in that: A plurality of discharge ports (230) are circumferentially and uniformly opened on the connecting ring sleeve (23). A filter hole plate (242) is jointly limited and connected between the driving rotating rod (240) and the connecting ring sleeve (23).

9. A poly-2-vinylpyridine evaporation crystallization device according to claim 7, characterized in that: A sliding floating plate (243) is sleeved outside the driving rotating rod (240). A connecting sliding sleeve (244) that is sleeved on the driving rotating rod (240) is jointly connected between the sliding floating plate (243) and the filter hole plate (242), and the connecting sliding sleeve (244) penetrates through the partition ring plate (20).

10. A method for evaporative crystallization of poly-2-vinylpyridine, using an evaporative crystallization device for poly-2-vinylpyridine according to any one of claims 1-9, characterized in that, The crystallization method includes the following steps: S1: The dehydrated and evaporated alkaline kettle residue from the vinylpyridine production line is mixed with deionized water for dilution. The diluted organic phase mixed solution is pre-introduced into the storage cylinder (21) for temporary storage, and a nitric acid solution is injected into the evaporation chamber (100) inside the reactor (1) for reaction; S2: Heat up the nitric acid solution in the reactor (1), and at the same time, extract the gas in the evaporation chamber (100) through the pre-processor (22) to form a micro-vacuum environment, avoiding deflagration, and driving the hot air flow during the extraction process through the storage cylinder (21) to preheat the organic phase mixture in the storage cylinder (21); S3: Inject the preheated organic phase mixture into the evaporation chamber (100) to carry out an oxidation reaction with the nitric acid solution. During the reaction process, the temperature in the reactor (1) rises, the nitric acid solution evaporates, is discharged through the connecting conduit (222) and condensed to recover the nitric acid solution. Mechanically induce to accelerate the reaction crystallization of the nitric acid solution and the organic phase mixture, and use centrifugal force to separate the precipitated picolinic acid nitrate crystals from the reaction solution; S4: The crystals separated out in the evaporation chamber (100) are introduced into the crystallization chamber (101), and an alkaline aqueous phase is injected into the crystallization chamber (101) to further separate and purify the organic phase crystals and neutralize the reaction solution. Then, secondary evaporation crystallization is carried out on the neutralized solution in the crystallization chamber (101) to obtain granular potassium nitrate. Finally, the mother liquor in the crystallization chamber (101) is evaporated to dryness, the obtained solid mixture is rinsed with absolute ethanol, the solid is dried to obtain the powdered potassium nitrate product, and the ethanol solution is evaporated and crystallized to obtain the picolinic acid product.

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