Automobile coating water-based waste solvent recycling system

Abstract

The invention relates to the field of automobile production, in particular to an automobile coating water-based waste solvent recycling system. The system comprises a waste solvent collecting box, a suspension separating system, a primary filtering system, a precise filtering system, a ceramic RO membrane system, a backwashing box system, a solvent proportioning system and a fresh solvent circulating system which are connected in sequence, in the water-based spraying process of the coating workshop, a waste solvent recovery system is introduced, and water and a solvent are separated from the cleaning waste liquid of the spraying robot for secondary recycling, so that the emission can be reduced, and the outsourcing treatment or sewage treatment cost can be reduced; valuable ethylene glycol butyl ether is recycled, and the consumption of pure water is reduced; energy conservation and emission reduction are effectively promoted, and a competitive energy-saving, environment-friendly and efficient coating workshop is strived to be created; and green low-carbon circular economy is practiced.

Description

Technical Field

[0001] The invention relates to the field of automobile production, and in particular to a system for recycling automobile painting aqueous waste solvent. Background Art

[0003] At present, the coating process in the automotive coating industry is 3C2B, the midcoat and color paint are water-based paint, and the varnish is oil-based paint; the ratio of water-based solvent is 1 part solvent (pure solvent content 95%) + 8 parts pure water, and the solvent content after mixing is about 11%; the components of water-based solvent are ethylene glycol butyl ether, ethanol, amines, special surfactants, defoaming agents, and pure water; the coating workshop can realize multi-color customized production, about half of the color paints are supplied through the main PCS system, and the other half of the color paints need to be fed through the ball system. Every time the ball system changes the paint supply, the ball barrel cover and ball module of the paint mixing room need to be cleaned, which produces a large amount of water-based waste solvents, with an average water-based waste solvent generation of 37 kg / time; the middle and surface coating spraying are all automatic spraying by robots, the middle coating internal spraying and the color paint internal atomizer cup cleaning 2 vehicles 1 time, the toilet cleaning 2 vehicles 1 time; the middle coating and color paint external atomizer cup cleaning 1 vehicle 1 time times, 2 toilets cleaned 1 time, waste liquid from color change cleaning of midcoat and color paint spray robot, waste liquid from toilet cleaning of midcoat and color paint spray robot, waste liquid from cleaning of midcoat and color paint internal spray cup, waste liquid from cleaning of ball bearing barrel cover and module during color change of color paint; the average amount of aqueous waste solvent generated by midcoat and color paint robot color change cleaning plus ball bearing color change cleaning is 4.8 kg / unit; the workshop generates a large amount of aqueous waste solvent every day, which is discharged to the paint mixing room through collection and transportation to the hazardous waste treatment station. The waste liquid after cleaning includes solvent cleaning liquid + paint + water, and the COD is as high as 0.286 mg / L. The sewage station cannot treat aqueous waste solvents and needs to treat them as hazardous waste, which is expensive. The factory needs to spend about 403,000 yuan per year on hazardous waste treatment under the condition of 240,000 units per year, which significantly increases the production cost. The cost of outsourcing hazardous waste for a single aqueous waste liquid is as high as 16.8 yuan per unit. This traditional technology will cause a large amount of hazardous waste to be generated every year, and the factory's operating costs are also very high. Summary of the invention

[0004] In order to solve the above problems, a system and method for recycling water-based waste solvents from automobile painting is proposed. The specific technical solution is as follows: A system for recycling water-based waste solvents for automobile painting: the system comprises a water-based waste solvent collection tank, a suspension separation system, a primary filtration system, a precision filtration system, a ceramic RO membrane system, a backwash tank system, a solvent proportioning system, and a fresh solvent circulation system connected in sequence; The aqueous waste solvent generated by the spraying equipment in the painting workshop is collected through pipelines to the aqueous waste solvent collection box for preliminary precipitation, and then enters the suspension separation system through a booster pump to separate the waste solvent containing paint and paint residue. The separated paint residue is collected, and the separated waste solvent enters the primary filtration system and the precision filtration system in turn. The primary filtration system uses filter bag filter elements for filtration; then it enters the ceramic RO membrane system for desalination and clarification treatment, and the treated solvent enters the proportioning system for re-proportioning; then it enters the fresh solvent circulation tank for spraying in the painting workshop, and the concentrated high-concentration waste solvent is collected and treated in an environmentally friendly manner; at the same time, the ceramic RO membrane system has an external backwashing system, and the backwashing system can be used for reverse osmosis flushing when the membrane is blocked.

[0005] Furthermore, the suspension separation system adopts a one-standby-one-use configuration.

[0006] Furthermore, the solvent proportioning system is provided with an automatic liquid level detection and concentration detection device, and is connected to a replenishing pure solvent tank, and the PLC automatically replenishes fresh pure solvent according to the detected liquid level and concentration data.

[0007] Furthermore, the ceramic RO membrane system is provided with a high-concentration waste solvent discharge port.

[0008] The suspension separation system set up in the present application can separate impurities such as paint and paint residue from the wastewater solvent through the suspension separation system. The separated aqueous waste solution is then filtered through primary filtration and tight filtration before entering the ceramic RO membrane system for filtration. The principle of the ceramic RO membrane is utilized, based on cross-flow filtration, and the pressure difference on both sides of the membrane is used as the driving force to allow small molecules to pass through the membrane, while large molecules are retained, thereby achieving separation, concentration, and purification. It can be used here to allow solvents with small molecules to pass through, while paint residue and other coatings with larger molecules can be intercepted, thereby achieving the recycling of the wastewater solvent.

[0009] The present invention introduces a waste solvent recovery system into the water-based spraying process in the painting workshop, separates the water and solvent from the spray robot cleaning waste liquid for secondary reuse, which can reduce emissions and reduce outsourcing or sewage treatment costs; reuse valuable ethylene glycol butyl ether and reduce pure water consumption; effectively promote energy conservation and emission reduction, strive to create the most competitive energy-saving, environmentally friendly and efficient painting workshop; and practice a green and low-carbon circular economy.

[0010] The system of the present invention has simple process, low investment and operation cost, convenient operation and management, and can be widely used in the spraying process of automobile manufacturing, parts manufacturing, furniture manufacturing and other industries. In order to protect the ecological environment and achieve sustainable economic and social development, it is necessary to reduce pollutants as much as possible in all links of industrial production, and at the same time, the pollutants should be recycled and processed at the end of the discharge to minimize pollutant emissions. After the fly ash solution of the paint shop is treated by this scheme, the equipment runs stably and reliably, greatly reducing the total amount of waste solution discharged by the enterprise, and has significant social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic structural diagram of a system for recycling aqueous waste solvents from automobile painting according to the present invention. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] like Figure 1 As shown: A system for recycling water-based waste solvents for automobile painting: the system includes a water-based waste solvent collection tank, a suspension separation system, a primary filtration system, a precision filtration system, a ceramic RO membrane system, a backwash tank system, a solvent proportioning system, and a fresh solvent circulation system connected in sequence; The aqueous waste solvent generated by the spraying equipment in the painting workshop is collected through pipelines to the aqueous waste solvent collection box for preliminary precipitation, and then enters the suspension separation system through a booster pump to separate the waste solvent containing paint and paint residue. The separated paint residue is collected, and the separated waste solvent enters the primary filtration system and the precision filtration system in turn. The primary filtration system uses filter bag filter elements for filtration; then it enters the ceramic RO membrane system for desalination and clarification treatment, and the treated solvent enters the proportioning system for re-proportioning; then it enters the fresh solvent circulation tank for spraying in the painting workshop, and the concentrated high-concentration waste solvent is collected and treated in an environmentally friendly manner; at the same time, the ceramic RO membrane system has an external backwashing system, and the backwashing system can be used for reverse osmosis flushing when the membrane is blocked.

[0014] The suspension separation system adopts a one-for-one setup. The solvent proportioning system is equipped with an automatic liquid level detection and concentration detection device, and is connected to the pure solvent replenishment tank. The PLC automatically replenishes fresh pure solvent based on the detected liquid level and concentration data. The ceramic RO membrane system is equipped with a high-concentration waste solvent discharge outlet for hazardous waste treatment.

[0015] The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A system for recycling water-based waste solvents from automobile painting, characterized by: The system comprises an aqueous waste solvent collection box, a suspension separation system, a primary filtration system, a precision filtration system, a ceramic RO membrane system, a backwashing box system, a solvent proportioning system, and a fresh solvent circulation system, which are connected in sequence; the aqueous waste solvent generated by the spraying equipment in the painting workshop is collected in the aqueous waste solvent collection box through a pipeline for preliminary precipitation, and then enters the suspension separation system through a booster pump to separate the waste solvent containing paint and paint residue, and the separated paint residue is collected, and the separated waste solvent enters the primary filtration system and the precision filtration system in sequence, and the primary filtration system adopts a filter bag filter element for filtration; then enters the ceramic RO membrane system for desalination and clarification treatment, and the obtained treated solvent enters the proportioning system for re-proportioning; then enters the fresh solvent circulation tank for spraying in the painting workshop, and the concentrated high-concentration waste solvent is collected and then treated in an environmentally friendly manner; at the same time, the ceramic RO membrane system has an external backwashing system, and reverse osmosis flushing can be performed through the backwashing system when the membrane is blocked.

2. The automobile painting aqueous waste solvent recovery and utilization system according to claim 1, characterized in that: The suspension separation system adopts a one-standby-one-use configuration.

3. The automobile painting aqueous waste solvent recovery and utilization system according to claim 1, characterized in that: The solvent proportioning system is provided with an automatic liquid level detection and concentration detection device, and is connected to a replenishing pure solvent tank, and the PLC automatically replenishes fresh pure solvent according to the detected liquid level and concentration data.

4. The automobile painting aqueous waste solvent recovery and utilization system according to claim 1, characterized in that: The ceramic RO membrane system is provided with a high-concentration waste solvent discharge port.

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