Polyether recovery device

Abstract

A polyether recovery device relates to the technical field of polyether treatment. Comprising a filter, a water storage tank and a filtrate collection tank, the bottom of the filter is provided with a slag discharge port, the side part of the filter is provided with a feed port, a filtrate outlet and a nitrogen inlet, the feed port of the filter is used for inputting polyether materials, the slag discharge port of the filter is connected with a slag discharge valve, and the filtrate outlet of the filter is connected with the filtrate collection tank; a plurality of metal filter screens which are arranged at intervals are arranged in the filter, a spray head with a nozzle facing the metal filter screens is also arranged in the filter, the water storage tank is connected with the spray head in the filter through a circulating pump, and the spray head is used for washing filter residues on the metal filter screens. According to the utility model, water is used as a solvent for cleaning polyether filter residues, and the recovered filtrate is further used as make-up water of the next batch and is directly added into the refining kettle, so that the problems of waste water and waste liquid generated by other solvents are avoided.

Description

Technical Field

[0001] This utility model relates to the field of polyether treatment technology, and in particular to a polyether recovery device. Background Technology

[0002] Polyether is obtained by polymerizing compounds containing active hydrogen with ethylene oxide, propylene oxide, etc., under the action of a catalyst. When potassium hydroxide is used as a catalyst, crude polyether is generated after the polymerization reaction. This crude polyether is then purified in a refining reactor to remove residual potassium ions (the potassium ion content in the product is generally ≤30ppm) before it can be used normally. The traditional polyether refining process involves adding soft water and phosphoric acid to the crude polyether, stirring and neutralizing at a certain temperature, adding an adsorbent, stirring for a period of time, and then dehydrating and filtering. After the potassium ion content is less than a specified value, the product is discharged, yielding qualified polyether and filter residue. This filter residue contains 20-35% polyether polyol, 40-55% potassium dihydrogen phosphate, and 15-25% magnesium silicate. Direct discharge of this residue not only severely pollutes the environment but also results in a huge waste of resources. It can only be treated as solid waste with a charge. The filter residue not only reduces product yield but also increases costs, squeezing the profit margin of polyether products. Therefore, effectively separating polyether filter residue has significant economic and environmental benefits.

[0003] CN201310198301.5 describes a method for extracting effective components from polyether filter residue. The method involves sedimentation, centrifugation, filtration, and crystallization to recover polyether and phosphate, with a polyether recovery rate of 95%. The process involves heating to above 100℃ and sedimentation for at least 10 hours to obtain an upper layer of liquid polyether, a middle layer of saturated polyether residue, and a lower layer of whitish polyether residue. The liquid polyether is then separated. The saturated and whitish polyether residues are centrifuged to obtain a mixed liquid and phosphate-containing solids, which are then separated. The mixed liquid is filtered through a plate and frame filter to obtain a phosphate liquid, which is then concentrated by heating and cooled to 30–50℃ for crystallization, separating the phosphate. However, due to the high viscosity of the filter residue, even at temperatures above 100℃, it still takes more than 10 hours for stratification to occur, resulting in a long unit operation time and significant differences in separation efficiency between different polyethers. Furthermore, the phosphate solids obtained through centrifugation may contain entrained polyether, affecting both the polyether recovery rate and the quality of the phosphate. Polyether residue will still remain in the filter residue after filtration of the mixed liquor, affecting the recovery rate.

[0004] CN201320775560.5 describes a polyether filter residue treatment device that achieves maximum area extraction of polyether filter residue from the production process, thereby improving the polyether yield. The device includes a polyether synthesis tower connected to a filter via pipe. The filter contains a filter screen and is connected to a polyether receiving tank via pipe. A spray head is located at the top of the filter, and the bottom of the filter is connected sequentially to a recovery vessel, a distillation unit, and an alcohol tank via pipe. The alcohol tank is connected to the spray head via pipe, and the distillation unit is connected to a collection tank via pipe. However, due to the lack of mechanical disturbance within the filter, the filter cake layer is densely packed. The high viscosity of the polyether and the obstruction caused by the filter screen also hinder mass transfer, negatively impacting the dissolution of polyether in ethanol and thus affecting the polyether recovery rate. Furthermore, distilling ethanol requires significant energy consumption. Additionally, this patent cannot achieve the separation of phosphate and adsorbent.

[0005] CN201820764297.2 describes a polyether refining and waste residue separation device. The device involves collecting filter residue from a filter into a washing tank, washing and allowing it to settle. The upper layer of polyether is then dehydrated in a dewatering kettle to obtain recycled polyether. The lower layer of solids is centrifuged to obtain magnesium silicate. The recycled polyether obtained from filtration can be used as cement raw material.

[0006] Currently, other methods for treating polyether filter residue involve adding the residue to a treatment vessel, adding water or ethanol, stirring and allowing it to stand at a certain temperature, resulting in a liquid phase on top and a solid phase on the bottom. The upper liquid phase is removed and dehydrated to obtain the polyether product. However, this polyether product is dark in color, has a high acid value, and a very high potassium ion content, and can only be treated as a low-grade polyether. The lower solid phase is removed and centrifuged to remove small molecules, yielding a mixture containing potassium dihydrogen phosphate and magnesium silicate. Currently, this mixture has no good applications and is generally treated as general solid waste. Separating the potassium dihydrogen phosphate-magnesium silicate mixture requires adding a large amount of water as a solvent to dissolve the potassium dihydrogen phosphate before separating the solid magnesium silicate. This method consumes a large amount of water and is not economically viable. Utility Model Content

[0007] The purpose of this invention is to provide a polyether recovery device that can effectively solve the problem of difficult recovery of residual polyether in polyether filter residue, improve the yield of polyether products, and has a green and environmentally friendly effect.

[0008] The technical solution to achieve the above objective is: a polyether recovery device, including a filter, a water storage tank, and a filtrate collection tank. The bottom of the filter is provided with a slag discharge port, and the side of the filter is provided with a feed port, a filtrate outlet, and a nitrogen inlet. The feed port of the filter is used to input polyether material, the slag discharge port of the filter is connected to a slag discharge valve, and the filtrate outlet of the filter is connected to the filtrate collection tank.

[0009] The filter contains multiple metal filter screens arranged at intervals, and also contains nozzles with spray nozzles facing the metal filter screens. The water storage tank is connected to the nozzles in the filter through a circulation pump, and the nozzles are used to rinse the filter residue on the metal filter screens.

[0010] Furthermore, the metal filter screen is provided with multiple parallel spacings, wherein the feed inlet and the filtrate outlet are respectively located on the filter sidewall on the opposite side of the metal filter screen.

[0011] Furthermore, multiple nozzles are provided, and the nozzles are connected to each other through pipelines. Some of them are installed on the top of the metal filter, and others are installed on the side wall of the metal filter around the metal filter, so that the nozzles can be aimed at the metal filter screen from different angles to rinse it.

[0012] Furthermore, the nozzles at the top and the nozzles around the metal filter are arranged in a ring shape.

[0013] Furthermore, a Venturi injector located outside the filter is also connected between the circulation pump and the nozzle.

[0014] Furthermore, the metal filter screen is installed inside the filter via a filter screen bracket.

[0015] Furthermore, the filtrate collection tank is equipped with a nitrogen inlet, which is connected to a nitrogen source via a control valve.

[0016] Furthermore, the filtrate collection tank is connected to the refining vessel in the polyether production process to use the collected filtrate as makeup water for the refining vessel.

[0017] The beneficial effects of this utility model are as follows: (1) This utility model uses water as the solvent for cleaning polyether filter residue, and the recovered filtrate is further added directly to the refining kettle as supplementary water for the next batch, avoiding the wastewater and waste liquid problems generated by other solvents; (2) This utility model is also equipped with a Venturi injector, which can reduce the amount of water used for cleaning polyether filter residue to only 40% of that used in conventional processes; (3) This utility model is equipped with 9 to 10 nozzles on the top and sides inside the filter, and the nozzles form a ring spray, which further reduces the amount of water used for cleaning polyether filter residue; (4) This utility model can effectively improve the polyether recovery rate, and the polyether recovery rate reaches more than 95%. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall device of this utility model. Detailed Implementation

[0019] To make the objectives, technical solutions and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0020] This utility model discloses a polyether recovery device, including a filter 1, a water storage tank 2, and a filtrate collection tank 3. The filter 1 is provided with a closed cavity, and a slag discharge port 1.2 is provided at the bottom of the filter 1. The side of the filter is provided with a feed port 1.1, a filtrate outlet 1.3, and a nitrogen inlet 1.4. The feed port 1.1 of the filter 1 is used to input polyether material. The slag discharge port 1.2 of the filter 1 is connected to a slag discharge valve 4. The filtrate outlet 1.3 of the filter 1 is connected to the filtrate collection tank 3. The nitrogen inlet 1.4 is connected to a nitrogen source through a control valve 5.

[0021] The filter 1 is equipped with multiple metal filter screens 6 arranged at intervals through the filter screen support 11. The feed inlet 1.1 and the filtrate outlet 1.3 are located on the side wall of the filter 1 opposite to the metal filter screens 6. The two side walls of the metal filter screens 6 are sealed to the side wall of the filter 1 (the specific installation and sealing structure of the metal filter screens are conventional settings of existing filters and will not be described in detail here).

[0022] The filter 1 is also equipped with a nozzle 7 with the nozzle facing the metal filter screen. The water storage tank 2 is connected to the nozzle 7 in the filter 1 through a circulation pump 9. The nozzle 7 is used to rinse the filter residue on the metal filter screen 6. In order to improve the rinsing effect, a Venturi injector 10 located outside the filter 1 is also connected between the circulation pump 9 and the nozzle 9.

[0023] There are 9 to 10 nozzles 7, which are connected by pipes. 3 to 4 of them are arranged on the top of the filter 1 above the metal filter screen 6, and the remaining 6 to 7 are arranged on the side walls of the filter 1 around the metal filter screen 6. The nozzles 7 on the top and the nozzles 7 around the metal filter screen 6 are arranged in a ring, forming a multi-angle and multi-layer rinsing structure.

[0024] After rinsing, nitrogen is introduced through nitrogen inlet 1.4, and the filtrate enters the filtrate collection tank 3 under nitrogen pressure.

[0025] The filtrate collection tank 3 is also connected to the refining tank 8 in the polyether production process. It is used to use the collected filtrate as supplement water for the refining tank 8 and to recover the polyether product in the filtrate. The refining tank 8 is also connected to the feed port 1.1 of the filter 1 through the feed valve 12 to input the generated polyether material into the filter 1.

[0026] Production example of this utility model:

[0027] First, 20m 3 The polyether material (including approximately 200 kg of filter residue) in refining vessel 8 is fed into inlet 1.1.

[0028] The polyether product is filtered out in filter 1, and the filter residue remains on the metal filter screen 6.

[0029] Then, the 50kg of water in the storage tank 2 is further pressurized by the venturi injector 10 through the circulation pump 9, and then evenly sprayed from different angles onto the filter residue on the metal filter screen 6 through the nozzle 7 to wash out the polyether in the filter residue.

[0030] After cleaning, open control valve 5 and introduce nitrogen gas to pressurize the polyether filtrate into filtrate collection tank 3. After pressing, the nitrogen gas is also used to purge the filter residue in the metal filter screen 6. The filtrate collected in filtrate collection tank 3 is then used as makeup water for the next batch of the refining kettle to recover the polyether product in the filtrate.

[0031] Approximately 245 kg of filtrate was weighed from filtrate collection tank 3, containing 50 kg of water, yielding approximately 193.2 kg of polyether. Compared to polyether products filtered using a conventional filter, the polyether recovery rate in the filter residue reached 96.6%.

Claims

1. A polyether recovery device, comprising a filter, a water storage tank, and a filtrate collection tank, wherein the bottom of the filter is provided with a slag discharge port, and the side of the filter is provided with a feed port, a filtrate outlet and a nitrogen inlet, the feed port of the filter is used to input polyether material, the slag discharge port of the filter is connected to a slag discharge valve, and the filtrate outlet of the filter is connected to the filtrate collection tank. The filter contains multiple metal filter screens arranged at intervals, and also contains nozzles with spray nozzles facing the metal filter screens. The water storage tank is connected to the nozzles in the filter through a circulation pump, and the nozzles are used to rinse the filter residue on the metal filter screens.

2. The polyether recovery device according to claim 1, characterized in that: The metal filter screen is provided with multiple parallel and spaced-apart screens, wherein the feed inlet and the filtrate outlet are located on the filter sidewalls opposite to the metal filter screens.

3. The polyether recovery device according to claim 2, characterized in that: The nozzles are provided in multiple parts and are connected by pipelines. Some of them are installed on the top of the metal filter and others are installed on the side wall of the metal filter around the metal filter, so that the nozzles can be aimed at the metal filter screen from different angles to rinse it.

4. The polyether recovery device according to claim 3, characterized in that: The nozzles at the top and the nozzles around the metal filter are arranged in a ring.

5. The polyether recovery device according to claim 1, characterized in that: A Venturi injector located outside the filter is also connected between the circulation pump and the nozzle.

6. The polyether recovery device according to claim 1, characterized in that: The metal filter screen is installed inside the filter via a filter screen bracket.

7. The polyether recovery device according to claim 1, characterized in that: The filtrate collection tank is equipped with a nitrogen inlet, which is connected to a nitrogen source via a control valve.

8. A polyether recovery device according to claim 1, characterized in that: The filtrate collection tank is connected to the refining vessel in the polyether production process and is used to use the collected filtrate as makeup water for the refining vessel.

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