Method and device for refining polyether polyol

Abstract

The invention relates to the field of polyether polyol refining, and discloses a method and a device for refining polyether polyol. The method comprises the following steps: sequentially neutralizing, filtering and removing ions from crude polyether polyol. The device comprises a mixing unit used for mixing crude polyether polyol with a neutralizing reagent; the filtering unit is used for filtering the materials passing through the mixing unit; and the ion removal unit is used for removing metal ions from the material passing through the filtering unit. When the method and the device are used for refining production of the polyether polyol, the production cost is low, the production efficiency is high, the content of volatile organic compounds in the polyether polyol can be remarkably reduced, the loss amount of polyether is greatly reduced, and the refined polyether polyol has the characteristics of low volatile organic compound content, small smell, high yield and the like. And the residual amount of alkali metal is small.

Description

Technical Field

[0001] This invention relates to the field of refined polyether polyols, and more specifically to methods and apparatus for refining polyether polyols. Background Technology

[0002] Polyether polyols are one of the main raw materials for the synthesis of polyurethane. The hydroxyl groups of polyether polyols react with polyisocyanates to produce polyurethane products such as foamed plastics, synthetic rubber, coatings, adhesives, synthetic leather, and chemical fibers. In addition, polyether polyols can also be used as nonionic surfactants, lubricants, fluids, and heat exchange fluids. Polyether polyols have developed rapidly and are widely used in various sectors of the national economy. The synthesis of polyether polyols typically involves ring-opening polymerization of epoxides such as ethylene oxide and propylene oxide on an initiator containing active hydrogen compounds, using alkali metals, alkaline earth metals, or their hydroxides as catalysts.

[0003] The crude polyether polyol obtained after polymerization is prone to containing alkaline metal ions. If the content of potassium, sodium, or other metal ions in the polyether polyol is too high during the reaction with isocyanate to produce polyurethane, the reaction will be violent, and the polyurethane product will be scrapped due to agglomeration. Therefore, the crude polyether polyol needs to undergo purification treatment to remove potassium, sodium, and other metal ions.

[0004] Currently, the main method for refining polyether polyols is the neutralization-filtration method. First, an acidic neutralizing agent is added to the crude polyether polyol to neutralize the alkaline metal ions in the crude polyether, generating alkali metal salts. Vacuum dehydration is then performed to allow the alkali metal salts to crystallize out. Finally, the solid alkali metal salts are removed by filtration to obtain the refined polyether polyol product.

[0005] CN 101775132A describes a purification process that does not require acid addition. At 60-120℃, water (0.1-10% of the total mass of crude ether polyol) and two adsorbents are used for 2-3 adsorption cycles, followed by filtration to obtain low-odor polyether polyol. The adsorbents used are magnesium silicate and diatomaceous earth, but the excessive number of adsorption cycles results in high costs. The above purification method is complex, requiring a long dehydration time to increase crystal size and improve the filtration efficiency of alkali metal salts. Furthermore, the high viscosity of polyether polyols leads to significant losses during filtration. Therefore, existing purification methods for polyether polyols suffer from complex processing steps, long processing times, and reduced yield. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of complex processing steps, long processing time, and reduced yield in the existing technology, and to provide a method for refining polyether polyols. This method has the characteristics of simple processing steps, low impurity content, and low polyether loss rate.

[0007] To achieve the above objectives, the present invention provides a method for refining polyether polyols, the method comprising:

[0008] The crude polyether polyol was subjected to neutralization, filtration, and ion removal treatment in sequence.

[0009] A second aspect of the present invention provides an apparatus for refining polyether polyols using the method described herein, the apparatus comprising:

[0010] A mixing unit is used to mix crude polyether polyol with a neutralizing agent;

[0011] A filtration unit is used to filter materials that have passed through the mixing unit;

[0012] The ion removal unit is used to remove metal ions from the material passing through the filtration unit.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects:

[0014] (1) The method and apparatus of the present invention are used to produce polyether polyols. This method not only has low production cost and high production efficiency, but also significantly reduces the content of volatile organic compounds in polyether polyols and greatly reduces the loss of polyether. The refined polyether polyols have the characteristics of low volatile organic compound content, low odor and low alkali metal residue.

[0015] (2) The method and apparatus described in this invention are simple to operate, require little time and investment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process for refining polyether polyols in a preferred embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures

[0018] 1. Mixing vessel; 2. Filter A; 3. Filter B; 4. Ion remover A; 5. Ion remover B; 6. Pre-filter buffer tank; 7. Evaporation buffer tank; 8. Multi-effect evaporator; 9. Crude polyether polyol storage tank; 10. Filter cartridge; 11. Distribution plate; 12. Ion-removed fiber; 13. Reinforced separation plate; 14. Level gauge; 15. Abnormal level; 16. Polyether polyol outlet of ion remover A; 17. Polyether polyol outlet of ion remover B; 18. Brine outlet of ion remover A; 19. Brine outlet of ion remover B; 20. Water outlet; 21. Salt outlet. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] In this invention, "device" refers to a unit composed of various components that have the same function and / or perform related functions.

[0021] A method for refining polyether polyols according to a first aspect of the present invention, the method comprising:

[0022] The crude polyether polyol was subjected to neutralization, filtration, and ion removal treatment in sequence.

[0023] In this invention, neutralization terminates the reaction and adjusts the pH of the material to form salts from metal ions; filtration removes polymer flocculents to prevent them from affecting subsequent ion removal treatment; ion removal accelerates ion removal and water coagulation; the method of this invention is simple to operate, time-saving, and requires little investment.

[0024] According to one embodiment of the present invention, ion-removing fibers are used to perform ion removal treatment on filtered materials, wherein the material of the ion-removing fibers includes anionic groups, preferably the anionic groups account for 0.1-2% by mass.

[0025] According to a preferred embodiment of the present invention, the anionic group is selected from one or more of sulfonic acid anionic groups, carboxylic acid anionic groups, and phosphate anionic groups.

[0026] According to one embodiment of the present invention, the ion-removing fiber includes at least one ion-removing fiber layer, preferably including at least three ion-removing fiber layers: a trapping layer that captures the metal ion dispersed phase, a growth layer that further expands the metal ion dispersed phase, and a release layer that rapidly discharges the metal ions that have passed through the growth layer.

[0027] In this invention, the metal ion dispersed phase refers to droplets smaller than 100 micrometers that exist in a free form within the crude polyether polyol. The trapping layer refers to the initial trapping of the metal ion dispersed phase droplets; the growth layer allows the metal ion dispersed phase to grow into droplets ≥200 μm; the detachment layer refers to the repulsion of droplets ≥200 μm by the material, thus forming droplets ≥1 mm, thereby enabling the metal ions to form a more stable complex and preventing secondary entrainment of the metal ions by the polyether polyol.

[0028] According to one embodiment of the present invention, the porosity of the trapping layer is 0.35 to 0.75.

[0029] According to one embodiment of the present invention, the porosity of the growth layer is 0.65 to 0.95.

[0030] According to one embodiment of the present invention, the porosity of the detachment layer is 0.25 to 0.45.

[0031] In this invention, the substrate material of the ion-removing fiber layer is selected from one or more of polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, and polyphenylene sulfide. The material of the trapping layer is selected from glass fiber and / or quartz fiber, the material of the growth layer is selected from at least one of polyacrylonitrile fiber, nylon fiber, and polyester fiber, and the material of the release layer is selected from at least one of ethylene polymer, propylene polymer, and styrene polymer.

[0032] In this invention, the ion-removing fiber has a multi-layer structure, with anionic groups grafted onto the surface of the middle layer, which is a technique well known to those skilled in the art.

[0033] According to one embodiment of the present invention, the total thickness of the ion-removed fibers is 0.01 to 15 cm, preferably 4 to 10 cm.

[0034] According to a preferred embodiment of the present invention, the ratio of the thickness of the capture layer, the thickness of the growth layer and the thickness of the detachment layer in the ion-removing fiber is (0-1):1:(0-1).

[0035] According to one embodiment of the present invention, the material is passed through the ions at an angle of 0 to 45° with the horizontal direction to remove fibers, preferably at an angle of 5 to 15° to remove fibers.

[0036] In this invention, the material is placed at a certain slope for ion removal of fibers. The tilt angle can avoid secondary entrainment of polyether material to a certain extent, and at the same time, it is more conducive to the separation of the two phases.

[0037] According to one embodiment of the present invention, the operating conditions for the ion removal treatment include: a temperature of 70 to 150°C, preferably 85 to 135°C.

[0038] According to one embodiment of the present invention, the operating conditions for the ion removal treatment include: a pressure of 0.1 to 1 MPa (gauge pressure).

[0039] In this invention, distributing the material before ion removal treatment can make the fluid distribution uniform and avoid fluctuations caused by uneven distribution.

[0040] According to a preferred embodiment of the present invention, the distribution process involves passing the material before ion removal treatment through a distribution plate with an opening ratio of 20-80%, preferably a distribution plate with an opening ratio of 45-75%.

[0041] According to a more preferred embodiment of the present invention, the diameter of the distribution holes on the distribution plate is 0.5 to 5 cm.

[0042] In this invention, the enhanced separation treatment of the material after ion removal can achieve the collision and aggregation of tiny droplets in the fluid, thereby promoting droplet enlargement and accelerating subsequent sedimentation and separation.

[0043] According to a preferred embodiment of the present invention, the enhanced separation process involves passing the ion-removed material through an enhanced separation plate with a surface modified by hydrophilicity.

[0044] According to a more preferred embodiment of the present invention, the surface water contact angle of the reinforced separation plate is controlled at 0 to 60°, preferably 0 to 10°.

[0045] In this invention, the reinforced separation plate is defined as a corrugated plate with folds. The material after ion removal treatment can increase the collision between droplets by passing through the reinforced separation plate, which can make the metal ion droplets grow larger and more conducive to sedimentation and separation.

[0046] In this invention, the crude polyether polyol is derived from the reaction of polyether polyols, but this does not limit the scope of the invention. The crude polyether polyol contains 0.98 to 0.995 kg / kg of polyether polyol.

[0047] According to one embodiment of the present invention, the crude polyether polyol contains 1000-3000 mg / kg of metal ions.

[0048] In this invention, the metal ions include monovalent metal ions such as potassium ions, sodium ions, or lithium ions.

[0049] According to one embodiment of the present invention, filtration involves passing the material through a filter element with a sieving accuracy of 0.1 to 100 μm, preferably 0.5 to 10 μm.

[0050] According to one embodiment of the present invention, neutralization involves adding crude polyether polyol to a neutralizing agent and mixing.

[0051] In this invention, the neutralizing agent is well known to those skilled in the art, such as one or more of phosphoric acid solution, sulfuric acid solution and adipic acid solution. The embodiments of this invention use phosphoric acid solution as an example, but do not limit the scope of this invention.

[0052] In this invention, the neutralizing agent is prepared by dissolving a certain amount of solute in water to form an aqueous solution of the required concentration. In the neutralizing agent, the mass ratio of solute to water is (0.15-6):1, preferably (1-3):1. As long as the purpose of this invention can be achieved, there are no special requirements for the water. It can be deionized water or water containing inorganic minerals. The water containing inorganic minerals can be tap water or formation water.

[0053] In this invention, the mixing refers to mixing in a way that allows the water-soluble components to fully dissolve and the water-insoluble components to fully disperse.

[0054] According to one embodiment of the present invention, the mass ratio of water to crude polyether polyol in the neutralization treatment is (0.01-0.3):1, preferably (0.05-0.15):1.

[0055] In this invention, the pH value of the neutralized mixed solution is weakly acidic, for example, 4.5 to 6.5. Specific pH values ​​are not given in the embodiments of this invention, but this does not affect the scope of this invention.

[0056] According to one embodiment of the present invention, the operating conditions for neutralization treatment include: a temperature of 70 to 150°C, preferably 85 to 135°C.

[0057] According to one embodiment of the present invention, the operating conditions for neutralization treatment include: a pressure of 0.1 to 1 MPa (gauge pressure).

[0058] In this invention, the filtration process involves passing the neutralized material through a filter element with a sieving accuracy of 0.1 to 100 μm, preferably through a filter element with a sieving accuracy of 0.5 to 10 μm. The material of the filter element is selected from one or more of sintered stainless steel, sintered ceramics, and glass fiber.

[0059] In this invention, the brine product after ion removal treatment is subjected to brine separation. The purpose of this is to precipitate the salt from the brine, avoid brine wastewater, and at the same time, the salt can be recovered to generate economic benefits.

[0060] According to a preferred embodiment of the present invention, the brine separation is performed by multi-effect evaporation of the material.

[0061] In this invention, as is well known to those skilled in the art, multi-effect evaporation refers to a series evaporation operation in which the secondary steam from the previous effect is used as the heating steam for the next effect. In multi-effect evaporation, the operating pressure, the corresponding heating steam temperature, and the solution boiling point of each effect decrease sequentially, thereby achieving solid recovery. The multi-effect evaporation equipment used in this invention is currently conventional, but this does not limit the scope of the invention.

[0062] According to one embodiment of the present invention, the refined polyether polyol contains: metal ion content ≤ 5 mg / kg; formaldehyde < 1 ppm, acetaldehyde < 1 ppm, and acrolein < 1 ppm.

[0063] According to a preferred embodiment of the present invention, the loss of polyether after purification is ≤0.005kg / kg.

[0064] According to a second aspect of the present invention, an apparatus for refining polyether polyols using the method described herein is provided, the apparatus comprising, in sequence connected:

[0065] A mixing unit is used to mix crude polyether polyol with a neutralizing agent;

[0066] A filtration unit is used to filter materials that have passed through the mixing unit;

[0067] The ion removal unit is used to remove metal ions from the material passing through the filtration unit.

[0068] In this invention, the apparatus used for refining polyether polyols according to the method described herein not only has low production cost and high production efficiency, but also significantly reduces the content of volatile organic compounds in polyether polyols and greatly reduces polyether loss. The refined polyether polyols have the characteristics of low volatile organic compound content, low odor, and low alkali metal residue. The operation is simple, time-consuming, and requires little investment.

[0069] According to one embodiment of the present invention, the mixing unit includes a mixing vessel.

[0070] According to one embodiment of the present invention, the filtration unit includes a filter, the filter employing a filter element with a sieving accuracy of 0.1 to 100 μm, preferably a filter element with a sieving accuracy of 0.5 to 10 μm.

[0071] According to one embodiment of the present invention, the material of the filter element is selected from one or more of sintered stainless steel, sintered ceramic and glass fiber.

[0072] According to one embodiment of the present invention, the ion removal unit includes an ion remover, and along the material flow direction, the ion remover is sequentially provided with a distribution plate, an ion removal fiber layer, and a reinforcing separation plate.

[0073] According to one embodiment of the present invention, the device further includes a multi-effect evaporator connected to the brine outlet of the ion remover, preferably the ion remover being connected to the multi-effect evaporator via an evaporation buffer tank.

[0074] According to one embodiment of the present invention, the mixing vessel is connected to the filter via a pre-filter buffer tank.

[0075] According to one embodiment of the present invention, the material passes along the transverse axis of the ion remover, and the transverse axis of the ion remover is fixed at an angle of 0 to 45° with the horizontal direction, preferably at an angle of 5 to 15° upward.

[0076] According to one embodiment of the present invention, the abnormal liquid level of the evaporation buffer tank is connected to the crude polyether polyol storage tank to recover the polyether polyol entrained in the brine phase.

[0077] In this invention, the polyether polyol refined by the method of this invention has low metal ion content, high purity, and low odor, making it suitable for the production of high-end products.

[0078] The embodiments of the present invention will now be described with reference to the accompanying drawings:

[0079] Crude polyether polyol, water, and phosphoric acid solution are added to mixing vessel 1 and neutralized by thorough stirring under certain conditions to obtain a mixed solution. The neutralized material is then filtered through pre-filtration buffer tank 6 into filter A 2 (filter B 3 is used as a backup). The filtered material then passes sequentially through ion remover A 4 and ion remover B 5. Low-odor, low-metal-ion-content polyether polyol products are obtained from polyether polyol outlet 16 of ion remover A and polyether polyol outlet 17 of ion remover B. Level gauge 14 is used to determine the levels of the brine phase and the polyether phase. The brine phase from brine outlet 18 of ion remover A and brine outlet 19 of ion remover B passes sequentially through evaporation buffer tank 7 and multi-effect evaporator 8 to achieve salt and water separation. Polyether polyol in evaporation buffer tank 7 with abnormal levels above 15 is discharged into crude polyether polyol storage tank 9.

[0080] The present invention will be described in detail below through embodiments.

[0081] In the following examples, the purity of the polyether polyol and the content of organic impurities were determined by HPLC; the water content was determined by Karl Fischer titration; and the metal ions were determined by ICP-MS / MS.

[0082] Example 1

[0083] like Figure 1As shown, the temperature in mixing vessel 1 is 95℃ and the pressure is 0.3MPa. Crude polyether polyol (polyether polyol content is 0.98kg / kg, metal ion content is 3000mg / kg) is dissolved in a phosphoric acid solution with a solute to water mass ratio of 3:1. After neutralization, the mass ratio of water to crude polyether polyol in the mixed solution is 0.05:1. The filter element has a filter precision of 2µm, the total thickness of the ion removal fibers is 4cm, the substrate material is polypropylene, and the mass percentage of grafted sulfonic acid anionic groups is 2%. The thicknesses of the capture layer (glass fiber), growth layer (polyacrylonitrile fiber), and release layer (ethylene polymer) are specified. The ratio of polyether polyols is 0.5:1:0.5, with porosities of 0.5, 0.8, and 0.4, respectively. The angle between the transverse axis of the ion remover and the horizontal direction is 10°. The operating temperature of the ion remover is 135℃, and the pressure is 0.3MPa. The porosity of the distribution plate is 65%, and the pore size is 3cm. The surface water contact angle of the reinforced separation plate is controlled at 5°. A polyether polyol product with low odor and low metal ion content is obtained from the polyether polyol outlet of the ion remover. The polyether polyol contains: metal ion content of 1.55mg / kg, formaldehyde of 0.5ppm, acetaldehyde of 0.5ppm, acrolein of 0.2ppm, and polyether loss of 3‰.

[0084] Example 2

[0085] like Figure 1 As shown, the temperature in mixing vessel 1 is 105℃ and the pressure is 0.5MPa. Crude polyether polyol (polyether polyol content is 0.99kg / kg, metal ion content is 2500mg / kg) is dissolved in a phosphoric acid solution with a solute to water mass ratio of 2:1. After neutralization, the mass ratio of water to crude polyether polyol in the mixed solution is 0.1:1. The filter element has a filter precision of 1µm, the total thickness of the ion removal fibers is 8cm, the substrate material is polyvinylidene fluoride, and the grafted carboxylic acid anionic groups account for 1.5% of the mass. The thicknesses of the capture layer (quartz fiber), growth layer (nylon fiber), and release layer (propylene polymer) are specified. The ratio of polyether polyols is 0.4:1:0.6, with porosities of 0.6, 0.75, and 0.35, respectively. The angle between the transverse axis of the ion remover and the horizontal direction is 15°. The operating temperature of the ion remover is 125℃, and the pressure is 0.5MPa. The porosity of the distribution plate is 60%, and the pore size is 4cm. The surface water contact angle of the reinforced separation plate is controlled at 10°. A polyether polyol product with low odor and low metal ion content is obtained from the polyether polyol outlet of the ion remover. The polyether polyol contains: 1.55mg / kg of metal ions, 0.3ppm of formaldehyde, 0.3ppm of acetaldehyde, 0.2ppm of acrolein, and a polyether loss of 2‰.

[0086] Example 3

[0087] like Figure 1 As shown, the temperature in mixing vessel 1 is 125℃ and the pressure is 1MPa. Crude polyether polyol (polyether polyol content is 0.98kg / kg, metal ion content is 2000mg / kg) is dissolved in a phosphoric acid solution with a solute-to-water mass ratio of 1:1. After neutralization, the mass ratio of water to crude polyether polyol in the mixed solution is 0.15:1. The filter cartridge has a filter accuracy of 5µm, the total thickness of the ion-removing fibers is 10cm, the substrate material is polypropylene, and the grafted phosphate anionic groups account for 1% of the mass. The thicknesses of the capture layer (glass fiber), growth layer (polyester fiber), and release layer (styrene polymer) are also specified. The ratio of the components is 0.8:1:0.7, and the porosities are 0.7, 0.9, and 0.3, respectively. The angle between the transverse axis of the ion remover and the horizontal direction is 5°. The operating temperature of the ion remover is 100℃, and the pressure is 1MPa. The porosity of the distribution plate is 50%, and the pore size is 5cm. The surface water contact angle of the reinforced separation plate is controlled at 1°. A polyether polyol product with low odor and low metal ion content is obtained from the polyether polyol outlet of the ion remover. The polyether polyol contains: metal ion content of 1.55mg / kg, formaldehyde of 0.2ppm, acetaldehyde of 0.2ppm, acrolein of 0.1ppm, and polyether loss of 0.5‰.

[0088] Example 4

[0089] like Figure 1 As shown, the temperature in mixing vessel 1 is 80℃ and the pressure is 0.3MPa. Crude polyether polyol (polyether polyol content is 0.98kg / kg, metal ion content is 3000mg / kg) is dissolved in a phosphoric acid solution with a solute to water mass ratio of 0.8:1. After neutralization, the mass ratio of water to crude polyether polyol in the mixed solution is 0.2:1. The filter element has a filter precision of 10µm, the total thickness of the ion removal fibers is 3cm, the substrate material is polypropylene, and the mass percentage of grafted sulfonic acid anionic groups is 1%. The thicknesses of the capture layer (glass fiber), the growth layer (polyacrylonitrile fiber), and the release layer (ethylene polymer) are... The ratio of the degrees is 1:1:1, and the porosities are 0.35, 0.65, and 0.25, respectively. The angle between the transverse axis of the ion remover and the horizontal direction is 20°. The operating temperature of the ion remover is 80℃, the pressure is 0.3MPa, the opening ratio of the distribution plate is 40%, the pore size is 2cm, and the surface water contact angle of the reinforced separation plate is controlled at 30°. A polyether polyol product with low odor and low metal ion content is obtained from the polyether polyol outlet of the ion remover. The polyether polyol contains: metal ion content of 85mg / kg, formaldehyde of 12.5ppm, acetaldehyde of 15.5ppm, acrolein of 9.2ppm, and polyether loss of 15‰.

[0090] Example 5

[0091] like Figure 1 As shown, the temperature in mixing vessel 1 is 60℃ and the pressure is 1MPa. Crude polyether polyol (polyether polyol content is 0.97kg / kg, metal ion content is 3000mg / kg) is dissolved in a phosphoric acid solution with a solute to water mass ratio of 0.2:1. After neutralization, the mass ratio of water to crude polyether polyol in the mixed solution is 0.25:1. The filter cartridge has a filter accuracy of 20µm, the total thickness of the ion removal fibers is 1cm, the substrate material is polypropylene, and the mass percentage of grafted sulfonic acid anionic groups is 0.1%. The thickness of the capture layer (glass fiber), the thickness of the growth layer (polyacrylonitrile fiber), and the thickness of the release layer (ethylene polymer) are also specified. The thickness ratio of the ions is 2:1:2, and the porosities are 0.3, 0.6, and 0.2, respectively. The angle between the transverse axis of the ion remover and the horizontal direction is 0°. The operating temperature of the ion remover is 80℃, the pressure is 1MPa, the opening ratio of the distribution plate is 30%, the pore size is 1cm, and the surface water contact angle of the reinforced separation plate is controlled at 60°. A polyether polyol product with low odor and low metal ion content is obtained from the polyether polyol outlet of the ion remover. The polyether polyol contains: metal ion content of 213mg / kg, formaldehyde of 16.5ppm, acetaldehyde of 27.5ppm, acrolein of 15.2ppm, and polyether loss of 25‰.

[0092] Example 6

[0093] like Figure 1 As shown, the temperature in mixing vessel 1 is 60℃ and the pressure is 0.1MPa. Crude polyether polyol (polyether polyol content is 0.97kg / kg, metal ion content is 3000mg / kg) is dissolved in a phosphoric acid solution with a solute to water mass ratio of 0.1:1. After neutralization, the mass ratio of water to crude polyether polyol in the mixed solution is 0.4:1. The filter cartridge has a filter accuracy of 200µm, the total thickness of the ion removal fibers is 0.005cm, the substrate material is polypropylene, and the mass percentage of grafted sulfonic acid anionic groups is 0.1%. The thickness of the capture layer (glass fiber), the thickness of the growth layer (polyacrylonitrile fiber), and the thickness of the release layer (ethylene polymer) are also specified. The thickness ratio of the materials is 2:1:2, and the porosities are 0.3, 0.6, and 0.2, respectively. The angle between the transverse axis of the ion remover and the horizontal direction is 60°. The operating temperature of the ion remover is 65℃, the pressure is 0.1MPa, the opening ratio of the distribution plate is 10%, the pore size is 6cm, and the surface water contact angle of the reinforced separation plate is controlled at 70°. A polyether polyol product with low odor and low metal ion content is obtained from the polyether polyol outlet of the ion remover. The polyether polyol contains: metal ion content of 415mg / kg, formaldehyde of 36.5ppm, acetaldehyde of 37.5ppm, acrolein of 26.2ppm, and polyether loss of 243‰.

[0094] Comparative Example 1

[0095] Existing technologies require an adsorbent process, with diatomaceous earth (containing magnesium silicate) adsorbent consumption accounting for 3.5‰ of the raw materials, while simultaneously forming 2% filter residue, of which polyether loss accounts for 40% of the filter residue. This process takes more than three times longer than the present invention. Furthermore, the polyether polyol contains: 5 mg / kg of metal ions, 6 ppm of formaldehyde, 5 ppm of acetaldehyde, and 10 ppm of acrolein.

[0096] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for refining polyether polyols, characterized in that, The method includes: The crude polyether polyol was subjected to neutralization, filtration, and ion removal treatment in sequence.

2. The method according to claim 1, wherein, The filtered material is subjected to ion removal treatment using ion removal fibers, wherein the ion removal fiber material includes anionic groups, preferably the anionic groups account for 0.1-2% by mass; Preferably, The ion-removing fiber includes at least one ion-removing fiber layer, preferably including at least three ion-removing fiber layers: a trapping layer that captures the metal ion dispersed phase, a growth layer that further expands and grows the metal ion dispersed phase, and a detachment layer that rapidly discharges the metal ions that have passed through the growth layer. More preferably, The porosity of the capture layer fibers is 0.35–0.75; and / or The fiber porosity of the growth layer is 0.65–0.95; and / or The porosity of the detachment layer fiber is 0.25–0.

45.

3. The method according to claim 2, wherein, The total thickness of the ion-removed fibers is 0.01–15 cm, preferably 4–10 cm; Preferably, the ratio of the thickness of the trapping layer, the thickness of the growth layer, and the thickness of the detachment layer in the ion-removing fiber is (0-1):1:(0-1); and / or The material is passed through the ions at an angle of 0 to 45° with the horizontal direction to remove fibers, preferably at an angle of 5 to 15°. and / or The operating conditions for the ion removal process include: The temperature is 70–150℃, preferably 85–135℃; And / or, the pressure is gauge pressure of 0.1 to 1 MPa.

4. The method according to any one of claims 1-3, wherein, The method also includes distributing the material before ion removal treatment; Preferably, the distribution process includes passing the material before ion removal treatment through a distribution plate with an opening ratio of 20-80%, more preferably a distribution plate with an opening ratio of 45-75%, and more preferably the pore diameter of the distribution holes is 0.5-5 cm. and / or The method also includes enhancing the separation process of the material after ion removal treatment; Preferably, the enhanced separation process involves passing the ion-removed material through an enhanced separation plate with a hydrophilically modified surface. Preferably, the surface water contact angle of the enhanced separation plate is controlled between 0 and 60°, and more preferably between 0 and 10°.

5. The method according to any one of claims 1-4, wherein, The crude polyether polyol contains: a polyether polyol content of 0.98–0.995 kg / kg; and / or a metal ion content of 1000–3000 mg / kg; and / or Filtration involves passing the material through a filter element with a screening accuracy of 0.1–100 μm, preferably 0.5–10 μm; and / or The neutralization process involves adding crude polyether polyol to a neutralizing agent and mixing. Preferably, the neutralizing agent includes one or more of phosphoric acid solution, sulfuric acid solution, and adipic acid solution.

6. The method according to claim 5, wherein, In the neutralizing reagent: the mass ratio of solute to water is (0.15–6):1, preferably (1–3):1; and / or In the neutralized mixed solution, the mass ratio of water to crude polyether polyol is (0.01–0.3):1, preferably (0.05–0.15):1; and / or The operating conditions for neutralization include: The temperature is 70–150°C, preferably 85–135°C; and / or The pressure is 0.1 to 1 MPa (gauge pressure).

7. The method according to any one of claims 1-6, wherein, The method also includes brine separation of the brine product after ion removal treatment; Preferably, the brine separation is achieved by multi-effect evaporation of the material; and / or The refined polyether polyol contains: metal ion content ≤5mg / kg; formaldehyde <1ppm, acetaldehyde <1ppm, acrolein <1ppm; Preferably, the loss of polyether after purification is ≤0.005kg / kg.

8. An apparatus for refining polyether polyols using the method of any one of claims 1-7, characterized in that, The device comprises the following components connected in sequence: A mixing unit is used to mix crude polyether polyol with a neutralizing agent; A filtration unit is used to filter materials that have passed through the mixing unit; The ion removal unit is used to remove metal ions from the material passing through the filtration unit.

9. The apparatus according to claim 8, wherein, The mixing unit includes a mixing vessel; and / or The filtration unit includes a filter, which uses a filter element with a sieving accuracy of 0.1–100 μm, preferably a filter element with a sieving accuracy of 0.5–10 μm; and / or The ion removal unit includes an ion remover, which, along the material flow direction, is sequentially provided with a distribution plate, an ion removal fiber layer, and a reinforcing separation plate.

10. The apparatus according to claim 9, wherein, The mixing vessel is connected to the filter via a pre-filter buffer tank; and / or The material passes along the transverse axis of the ion remover, which is fixed at an angle of 0–45° to the horizontal direction, preferably at an angle of 5–15° upwards; and / or The device also includes a multi-effect evaporator connected to the brine outlet of the ion remover, preferably the ion remover is connected to the multi-effect evaporator via an evaporation buffer tank; Preferably, the abnormal liquid level of the evaporation buffer tank is connected to the crude polyether polyol storage tank.

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