Recycling system for low-solid-content high-boiling-point coating water-based colored paint waste solvent

Abstract

The utility model discloses a recycling system for a low-solid-content high-boiling-point coating water-based colored paint waste solvent, which comprises a flocculation unit and a membrane separation unit, the flocculation unit comprises a reaction kettle, a filter and a mother liquor tank A, the filter is used for filtering turbid liquid, and the membrane separation unit comprises a primary membrane filtering device, a mother liquor tank B and a secondary membrane filtering device. And filtrate filtered and purified by the secondary membrane filtering device is extracted as a recovery solvent. The utility model relates to the technical field of vehicle waste solvent treatment. According to the recycling system for the low-solid-content high-boiling-point coating water-based colored paint waste solvent, a relatively simple and mature flocculation unit is used in the front section, and a membrane separation unit composed of a first-stage membrane filtering device and a second-stage membrane filtering device is used in the rear section; the combined use of the first-stage membrane filtering device and the second-stage membrane filtering device can further improve the recovery effect of the waste solvent, and the combination of two-stage membrane filtering can realize efficient separation and recovery of the low-solid-content coating water-based colored paint waste solvent.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle waste solvent treatment, in particular to a recycling system for waste solvent of low-solid-content and high-boiling-point water-based paint. Background Art

[0002] After searching, Chinese patent CN212357112U discloses a system for recycling waste solvents from water-based paint, including a flocculation unit, an adsorption unit, and a membrane separation unit. The flocculation unit includes a reactor for reacting the waste solvent of the paint with an aqueous solution of a flocculant, a filter for filtering the reaction product in the reactor, and a clear liquid tank for collecting the clear liquid after filtration. The adsorption unit includes a primary adsorption tower and a secondary adsorption tower for sequentially adsorbing the clear liquid in the clear liquid tank. The membrane separation unit includes a mother liquid tank for storing mother liquid and a membrane separation device for filtering the mother liquid in the mother liquid tank. The filtrate filtered by the membrane separation device is extracted as a recovered solvent. The recovery rate of effective components in the waste solvent of the paint of the utility model is ≥85%, and the reduction of hazardous waste is ≥85%.

[0003] As described above, the current recycling and reuse system for waste solvents from water-based paints uses a membrane separation unit to recover effective cleaning components in the waste solvents from the paints, thereby reducing hazardous waste, reducing the cost of hazardous waste treatment for enterprises and reducing the cost of cleaning agent raw materials, while ensuring that the recycling process is green and environmentally friendly. Waste solvents of different components have their own characteristics and physical properties. For waste solvents from paints with low solid content (absolute dry solid content within 3%) and solvent components with high boiling point solvents, since the low solid content means that the waste solvent contains a large amount of solvent components, under the condition of low solid content, the current recycling and utilization system for waste solvents from water-based paints, such as the single-stage membrane provided by Chinese patent CN212357112U, is difficult to effectively separate the target component from the solvent. For this reason, the applicant has designed a recycling and reuse system for waste solvents from water-based paints with low solid content and low boiling point to solve the above problems. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a system for recycling waste solvents from water-based paints with low solid content and high boiling point, which solves the problem that the single-stage membrane of the current system for recycling and reusing waste solvents from water-based paints is not suitable for treating waste solvents from paints with low solid content and high boiling point solvent components.

[0005] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] The recycling system for low-solid-content and high-boiling-point water-based paint waste solvent is suitable for paint waste solvent with low solid content (absolute dry solid content within 3%wt) and a solvent component of a high-boiling-point solvent.

[0007] The recycling system of waste solvent of low-solid-content and high-boiling-point water-based paint comprises a flocculation unit and a membrane separation unit;

[0008] The flocculation unit includes a reactor R101 for stirring the added paint waste solvent and the flocculant aqueous solution, a filter F101 for filtering the suspension formed by the reaction in the reactor R101, and a mother liquid tank AV101 for collecting the filtered clear liquid;

[0009] The membrane separation unit includes a primary membrane filtration device MS101 for filtering the material in the mother liquid tank AV101 as mother liquid, a mother liquid tank BV102 for storing the filtrate filtered by the primary membrane filtration device MS101 as mother liquid, and a secondary membrane filtration device MS102 for filtering the mother liquid in the mother liquid tank BV102. The filtrate filtered and purified by the secondary membrane filtration device MS102 is extracted as a recovered solvent.

[0010] The flocculation unit further comprises a suspension delivery pump AP101 for delivering the suspension in the reactor R101 to the filter F101.

[0011] The membrane separation unit further comprises a mother liquid delivery pump AP102 for delivering the mother liquid in the mother liquid tank AV101 to the primary membrane filtration device MS101.

[0012] The membrane separation unit further comprises a mother liquid delivery pump BP103 for delivering the mother liquid in the mother liquid tank BV102 to the secondary membrane filtration device MS102.

[0013] Wherein, the membrane filtration device adopts a ceramic membrane, a polytetrafluoroethylene membrane or a metal membrane, and the membrane pore size is 5-100nm.

[0014] The utility model provides a recycling system for waste solvents of low-solid-content and high-boiling-point coating water-based paints. A relatively simple and mature flocculation unit is used in the front section, and a membrane separation unit composed of a primary membrane filter device and a secondary membrane filter device is used in the back section. Since the waste solvent to be treated is high-boiling-point coating water-based paint, the use of the membrane separation device can effectively reduce energy consumption. At the same time, the combined use of the primary membrane filter device and the secondary membrane filter device can further improve the recovery effect of the waste solvent. The primary membrane filter device is mainly used to remove large molecules and impurities, while the secondary membrane filter device further removes residual small molecules and ions. This combination of two-stage membrane filtration can achieve efficient separation and recovery of waste solvents of low-solid-content coating water-based paints. By providing a pretreatment process, large particle impurities and suspended matter in the waste solvent can be effectively removed, the solid content can be reduced, and clogging and damage to the membrane can be reduced, thereby improving the applicability of membrane separation technology.

[0015] According to the measurement, the system for recycling waste solvent of water-based paint of the utility model has a recovery rate of effective components in the waste solvent of the paint of ≥85%, and a reduction of hazardous waste of ≥85%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a system structure diagram of the utility model;

[0017] In the figure: R101, reactor; P101, suspension delivery pump; F101, filter; V101, mother liquid tank A; P102, mother liquid delivery pump A; MS101, primary membrane filtration device; V102, mother liquid tank B; P103, mother liquid delivery pump B; MS102, secondary membrane filtration device. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0019] See also Figure 1 , the utility model provides a technical solution: a system for recycling waste solvents of low-solid content and high-boiling-point water-based paint, comprising a flocculation unit and a membrane separation unit;

[0020] The flocculation unit includes a reactor R101 for stirring the added paint waste solvent and the flocculant aqueous solution, a filter F101 for filtering the suspension formed by the reaction in the reactor R101, and a mother liquid tank AV101 for collecting the filtered clear liquid;

[0021] The membrane separation unit includes a primary membrane filtration device MS101 for filtering the material in the mother liquid tank AV101 as mother liquid, a mother liquid tank BV102 for storing the filtrate filtered by the primary membrane filtration device MS101 as mother liquid, and a secondary membrane filtration device MS102 for filtering the mother liquid in the mother liquid tank BV102. The filtrate filtered and purified by the secondary membrane filtration device MS102 is extracted as a recovered solvent.

[0022] The material in the clear liquid tank AV101 is respectively passed through the primary membrane filtration device MS101 and the secondary membrane filtration device MS102, and the filtrate is taken out as the recovery solvent, wherein the mother liquor in the mother liquor tank AV101 enters the primary membrane filtration device MS101, and its clear liquid enters the mother liquor tank BV102. After the mother liquor in the mother liquor tank AV101 is concentrated to a certain degree, it returns to the paint waste liquid storage tank, and the mother liquor in the mother liquor tank BV102 enters the secondary membrane filtration device MS102 to participate in the secondary membrane separation, and the separated clear liquid is taken out as the recovery solvent, and after the mother liquor in the mother liquor tank BV102 is concentrated to a certain degree, it is used as the backwashing liquid of the primary membrane filtration device MS101.

[0023] The flocculation unit further comprises a suspension delivery pump AP101 for delivering the suspension in the reactor R101 to the filter F101.

[0024] The membrane separation unit further comprises a mother liquid delivery pump AP102 for delivering the mother liquid in the mother liquid tank AV101 to the primary membrane filtration device MS101.

[0025] The membrane separation unit further comprises a mother liquid delivery pump BP103 for delivering the mother liquid in the mother liquid tank BV102 to the secondary membrane filtration device MS102.

[0026] Wherein, the membrane filtration device adopts a ceramic membrane, a polytetrafluoroethylene membrane or a metal membrane, and the membrane pore size is 5-100nm.

[0027] Among them, the reactor R101 is provided with a raw material inlet, a flocculant inlet, a material outlet and a material return port, wherein the material outlet is connected to the material inlet of the suspension delivery pump P101, and the material return port is connected to the material outlet of the suspension delivery pump P101. The suspension delivery pump P101 is provided with a material inlet and a material outlet, wherein the material inlet is connected to the material outlet of the reactor R101, and the material outlet is divided into two routes, one route is connected to the material return port of the reactor R101, and the other route is connected to the filter F101. The filter F101 is provided with a material inlet, a solid product outlet and a liquid product outlet, wherein the material inlet is connected to the suspension delivery pump P101, the solid product outlet is used to extract solid waste, and the liquid product outlet is connected to the mother liquid tank AV101. The mother liquid tank AV101 is provided with a material inlet and a material outlet, wherein the material inlet is connected to the liquid product outlet of the filter F101, and the material outlet is connected to the mother liquid delivery pump AP102. The mother liquid delivery pump AP102 is provided with a material inlet and a material outlet, wherein the material inlet is connected to the mother liquid tank AV101, the material outlet is connected to the mother liquor inlet of the primary membrane filtration device MS101, the primary membrane filtration device MS101 is provided with a material inlet at the bottom, a mother liquor outlet at the top, and a product outlet at the bottom, wherein the material inlet is connected to the mother liquor delivery pump AP102, the mother liquor outlet is connected to the mother liquor tank AV101, and the product is connected to the mother liquor tank BV102, the mother liquor tank BV102 is provided with a material inlet and a material outlet, wherein the material inlet is connected to the liquid product outlet of the primary membrane filtration device MS101, the material outlet is connected to the mother liquor delivery pump BP103, the mother liquor delivery pump BP103 is provided with a material inlet and a material outlet, wherein the material inlet is connected to the mother liquor tank BV102, the material outlet is connected to the secondary membrane filtration device MS102, the secondary membrane filtration device MS102 is provided with a material inlet at the bottom, a mother liquor outlet at the top, and a product outlet at the bottom, wherein the material inlet is connected to the mother liquor delivery pump BP103, the mother liquor outlet is connected to the mother liquor tank BV102, and the product outlet produces and recovers the solvent.

[0028] The processing steps are as follows:

[0029] The waste solvent of the paint is added to the reactor R101, and then the flocculant aqueous solution is added to the reactor R101. After sufficient stirring, it is transported to the filter F101 through the suspension delivery pump P101. The filter F101 filters out the solid impurities in the suspension after flocculation, and the clear liquid enters the mother liquid tank AV101. The mother liquid delivery pump AP102 transports the mother liquid to the primary membrane filtration device MS101. The filtrate separated by the primary membrane filtration device MS101 enters the mother liquid tank BV102 as the mother liquid, and the circulating liquid enters the mother liquid tank AV101. After the material in the mother liquid tank AV101 is concentrated to a certain degree, it is extracted as a waste solvent and enters the waste solvent tank for paint. The mother liquid delivery pump BP103 transports the mother liquid to the secondary membrane filtration device MS102. The filtrate treated by the secondary membrane filtration device MS102 is extracted as a recovered solvent, and the circulating solvent returns to the mother liquid tank BV102. After the material in the mother liquid tank BV102 is concentrated to a certain degree, it is used as the backwashing liquid of the primary membrane filtration device MS101.

[0030] The flocculant is a mixture of one or more of anionic polyacrylamide, cationic polyacrylamide, sodium polyacrylate, polysilicic acid, polyferric silicate, polyaluminum silicate and polyaluminum chloride.

[0031] Wherein, the flocculant aqueous solution is an aqueous solution with a mass concentration of 0.1%-20.0%.

[0032] Wherein, the mass ratio of the flocculant aqueous solution to the paint waste solvent is 0.1-2.0:4.0.

[0033] Processing Example 1

[0034] The waste solvent of the paint is added to the reactor R101, and then the flocculant aqueous solution is added to the reactor R101, wherein the flocculant aqueous solution is a mixed aqueous solution of polysilicate aluminum and polysilicate iron with a mass concentration of 20.0%, and the mass ratio of the flocculant aqueous solution to the waste solvent of the paint is 0.8:4.0. After sufficient stirring, it is transported to the filter F101 through the suspension delivery pump P101. The filter F101 filters out the solid impurities after flocculation, and the clear liquid enters the mother liquid tank AV101. The mother liquid delivery pump AP102 transports the mother liquid to the primary membrane filtration device MS101. The primary membrane filtration device MS101 adopts a 100nm polytetrafluoroethylene membrane. The filtrate treated by the primary membrane filtration device MS101 is used as the post The mother liquor of the subsequent process enters the mother liquor tank BV102, and the circulating solvent returns to the mother liquor tank AV101. After the material in the mother liquor tank AV101 is concentrated to a certain degree, it returns to the paint waste solvent tank, and the subsequent cycle continues to enter the reactor R101 for reaction treatment, and the mother liquor in the mother liquor tank BV102 is transported to the secondary membrane filtration device MS102 by the mother liquor transfer pump BP103. The secondary membrane filtration device MS102 adopts a 20nm ceramic membrane. The filtrate treated by the secondary membrane filtration device MS102 is extracted as a recovered solvent, and the circulating solvent returns to the mother liquor tank BV102. After the material in the mother liquor tank BV102 is concentrated to a certain degree, it is used for backwashing the membrane of the primary membrane filtration device MS101.

[0035] Processing Example 2

[0036] The waste solvent of the paint is added to the reactor R101, and then the flocculant aqueous solution is added to the reactor R101, wherein the flocculant aqueous solution is a mixed aqueous solution of polyacrylic acid and cationic polyacrylamide with a mass concentration of 0.4%, and the mass ratio of the flocculant aqueous solution to the waste solvent of the paint is 1.5:4.0. After sufficient stirring, it is transported to the filter F101 through the suspension delivery pump P101. The filter F101 filters out the solid impurities in the suspension after flocculation, and the clear liquid enters the mother liquid tank AV101. The mother liquid delivery pump AP102 transports the mother liquid to the primary membrane filtration device MS101. The primary membrane filtration device MS101 adopts a 100nm ceramic membrane. The filtrate enters the mother liquor tank BV102 as the mother liquor of the subsequent process, and the circulating solvent returns to the mother liquor tank AV101. After the material in the mother liquor tank AV101 is concentrated to a certain degree, it returns to the paint waste solvent tank, and then continues to enter the reactor R101 for reaction treatment. The mother liquor in the mother liquor tank BV102 is transported to the secondary membrane filtration device MS102 by the mother liquor transfer pump BP103. The secondary membrane filtration device MS102 adopts a 10nm metal membrane. The filtrate treated by the secondary membrane filtration device MS102 is extracted as a recovered solvent, and the circulating solvent returns to the mother liquor tank BV102. After the material in the mother liquor tank BV102 is concentrated to a certain degree, it is used for backwashing the membrane of the primary membrane filtration device MS101.

[0037] Processing Example 3

[0038] The waste solvent of the paint is added to the reactor R101, and then the flocculant aqueous solution is added to the reactor R101, wherein the flocculant aqueous solution is a polyaluminium chloride aqueous solution with a mass concentration of 15.0%, and the mass ratio of the flocculant to the waste solvent is 0.4:4.0. After sufficient stirring, it is transported to the filter F101 through the suspension delivery pump P101. The filter F101 filters out the solid impurities in the suspension after flocculation, and the clear liquid enters the mother liquid tank AV101. The mother liquid delivery pump AP102 transports the mother liquid to the primary membrane filtration device MS101. The primary membrane filtration device MS101 adopts a 50nm polytetrafluoroethylene membrane. The filtrate treated by the primary membrane filtration device MS101 is used as the subsequent process The mother liquor enters the mother liquor tank BV102, and the circulating solvent returns to the mother liquor tank AV101. After the material in the mother liquor tank AV101 is concentrated to a certain degree, it is returned to the paint waste solvent tank, and then continues to enter the reactor R101 for treatment. The mother liquor in the mother liquor tank BV102 is transported to the secondary membrane filtration device MS102 by the mother liquor transfer pump BP103. The secondary membrane filtration device MS102 adopts a 5nm metal membrane. The filtrate treated by the secondary membrane filtration device MS102 is extracted as a recovered solvent, and the circulating solvent returns to the mother liquor tank BV102. After the material in the mother liquor tank BV102 is concentrated to a certain degree, it is used for backwashing the membrane of the primary membrane filtration device MS101.

[0039] The utility model discloses a system for recycling waste solvents of low-solid-content and high-boiling-point coating water-based paint. The front section uses a relatively simple and mature flocculation unit, and the back section uses a membrane separation unit composed of a primary membrane filter device MS101 and a secondary membrane filter device MS102. Since the waste solvent to be treated is high-boiling-point coating water-based paint, the use of the membrane separation device can effectively reduce energy consumption. At the same time, the combined use of the primary membrane filter device MS101 and the secondary membrane filter device MS102 can further improve the recovery effect of the waste solvent. The primary membrane filter device MS101 is mainly used to remove large molecules and impurities, while the secondary membrane filter device MS102 further removes residual small molecules and ions. This combination of two-stage membrane filtration can achieve efficient separation and recovery of waste solvents of low-solid-content coating water-based paint. By providing a pretreatment process, large particle impurities and suspended matter in the waste solvent can be effectively removed, the solid content can be reduced, and clogging and damage to the membrane can be reduced, thereby improving the applicability of membrane separation technology.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A system for recycling waste solvents from low-solid-content and high-boiling-point water-based paints, comprising a flocculation unit and a membrane separation unit; The flocculation unit comprises a reactor (R101) for stirring the added paint waste solvent and the flocculant aqueous solution, a filter (F101) for filtering the suspension formed by the reaction in the reactor (R101), and a mother liquid tank A (V101) for collecting the clear liquid after filtration; Features: The membrane separation unit comprises a primary membrane filtration device (MS101) for filtering the material in the mother liquid tank A (V101) as a mother liquid, a mother liquid tank B (V102) for storing the filtrate filtered by the primary membrane filtration device (MS101) as a mother liquid, and a secondary membrane filtration device (MS102) for filtering the mother liquid in the mother liquid tank B (V102). The filtrate filtered and purified by the secondary membrane filtration device (MS102) is extracted as a recovery solvent.

2. The system for recycling waste solvent of low-solid-content and high-boiling-point water-based paint according to claim 1 is characterized in that: The flocculation unit further comprises a suspension delivery pump A (P101) for delivering the suspension in the reaction kettle (R101) to the filter (F101).

3. The system for recycling waste solvent of low-solid-content and high-boiling-point water-based paint according to claim 1, characterized in that: The membrane separation unit also includes a mother liquid delivery pump A (P102) for delivering the mother liquid in the mother liquid tank A (V101) to the primary membrane filtration device (MS101).

4. The system for recycling waste solvent of low-solid-content and high-boiling-point water-based paint according to claim 1 is characterized in that: The membrane separation unit also includes a mother liquid delivery pump B (P103) for delivering the mother liquid in the mother liquid tank B (V102) to the secondary membrane filtration device (MS102).

5. The system for recycling waste solvent of low-solid-content and high-boiling-point water-based paint according to claim 1, characterized in that: The membrane filtration device adopts a ceramic membrane, a polytetrafluoroethylene membrane or a metal membrane, and the membrane pore size is 5-100nm.

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