Oily wastewater treatment system for coating workshop

Abstract

The invention relates to the technical field of oily wastewater treatment, and particularly discloses a coating workshop oily wastewater treatment system. Comprising a wastewater collecting tank, a grid filtering device, an oil separation tank, a PH value adjusting device, a coagulation reaction device, a flocculation reaction device, a sedimentation tank, a supercritical water oxidation reactor, a cooling device, an ultraviolet disinfection device and a qualified water temporary storage tank which are connected in sequence, the supercritical water oxidation reactor is connected with a heating system, a pressurization system and an oxidant supply system, the supercritical water oxidation reactor is connected with a tail gas emission system, the cooling device is connected with the supercritical water oxidation reactor, and a pressure relief valve is arranged on the cooling device. According to the invention, oil, organic matters and other pollutants in the oil-containing wastewater can be efficiently and safely removed, so that the oil-containing wastewater reaches the discharge or reuse standard, and the comprehensive and environment-friendly requirements of oil-containing wastewater treatment are met.

Description

Technical Field

[0001] The invention belongs to the technical field of oily wastewater treatment, and in particular relates to an oily wastewater treatment system for a painting workshop. Background Art

[0002] With the development of the economy and society, the automobile industry has greatly driven the development of the national industry, and the automobile industry has become one of the national pillar industries. However, the development of the automobile industry has also brought about a series of environmental problems. The painting process of automobiles and their parts is an important link in the generation of wastewater in the automobile industry. Oily wastewater comes from the pre-treatment processes such as degreasing and phosphating in the pre-installation process. It contains resins, surfactants, petroleum substances, phosphates, suspended particles, organic matter and other pollutants. It has a high CODCr (dichromate index) value and a large oil content. If not properly handled, it will cause serious pollution to the environment.

[0003] The oily wastewater treatment device is an auxiliary device used to purify wastewater generated in the coating process in order to reduce pollution and better discharge it into the urban wastewater network. It has been widely used in the field of wastewater treatment. When the existing oily wastewater treatment device is used, the aerator and the motor are first electrically connected to the external power supply, and then the wastewater is transported to the aeration chamber through the water inlet pipe. The aerator is then turned on to generate a large number of microbubbles. The microbubbles are fully mixed with the wastewater and enter the reaction chamber through the drainage hole. A coagulant is then added to the reaction chamber through the scraping operation port to cause the coagulant to react with the impurities in the wastewater to flocculate. The generated floccules and the suspended solids contained in the wastewater rise continuously to the surface of the liquid through a large number of microbubbles, and then Then turn on the motor to drive the scraper to scrape off the floccules and suspended solids floating on the surface of the liquid, and discharge them through the sewage plate and the sewage outlet, and finally the remaining water can be discharged through the drain outlet; it is found in the use of the existing oily wastewater treatment device that the transmission chain of the scraper is often loose during use, which affects the scraping operation of the scraper and results in low reliability; and the remaining water after scraping still contains a large amount of synthetic organic matter, cyclic organic matter and aromatic organic matter, etc., and direct discharge will still cause pollution to the environment, resulting in poor practicality.

[0004] Therefore, we propose a paint shop oily wastewater treatment system to solve the above technical problems. Summary of the invention

[0005] In order to solve the technical problem that the oily wastewater in the prior art still contains a large amount of synthetic organic matter, cyclic organic matter and aromatic organic matter after treatment, and direct discharge still causes pollution to the environment, the present invention proposes a painting workshop oily wastewater treatment system.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A coating workshop oily wastewater treatment system comprises a wastewater collection tank, a grid filter device, an oil separator, a pH value adjustment device, a coagulation reaction device, a flocculation reaction device, a sedimentation tank, a supercritical water oxidation reactor, a cooling device, an ultraviolet disinfection device and a qualified water temporary storage tank which are sequentially connected through pipelines, wherein the sedimentation tank is connected to a sludge treatment device, the supercritical water oxidation reactor is connected to a heating system, a pressurizing system and an oxidant supply system, which are respectively used to provide a high-temperature environment, a high-pressure environment and an oxidizing environment to the supercritical water oxidation reactor, the supercritical water oxidation reactor is connected to an exhaust gas emission system, the cooling device is connected to the supercritical water oxidation reactor, and is used to reduce the temperature of the treated water, and the cooling device is provided with a pressure release valve.

[0008] In a further technical solution, the heating system includes a heater, a temperature sensor and a temperature controller, the heater is installed on a pipeline between the precipitation device and the supercritical water oxidation reactor, the temperature sensor is installed at the inlet of the supercritical water oxidation reactor, and the heater and the temperature sensor are both electrically connected to the temperature controller.

[0009] In a further technical solution, the pressurizing system includes a high-pressure pump, a pressure regulating valve, a pressure sensor and a high-pressure safety valve. The high-pressure pump is installed on the pipeline between the precipitation device and the supercritical water oxidation reactor. The pressure regulating valve, the pressure sensor and the high-pressure safety valve are installed in sequence on the outlet pipeline of the high-pressure pump. The high-pressure safety valve is electrically connected to the pressure sensor.

[0010] In a further technical solution, the pressurizing system further includes a high-pressure storage tank, which is installed on an outlet pipe of the high-pressure pump, and the pressure sensor and the high-pressure safety valve are installed on the high-pressure storage tank.

[0011] In a further technical solution, the oxidant supply system includes an oxidant storage tank, a delivery pump and a flow control valve. The oxidant storage tank is connected to the supercritical water oxidation reactor through a pipeline, and the delivery pump and the flow control valve are installed in sequence on the pipeline between the oxidant storage tank and the supercritical water oxidation reactor.

[0012] In a further technical solution, a heat recovery device is also included, which includes a cooling circulation pipeline and a circulation pump installed on the cooling circulation pipeline. The cooling device is connected to the heating system through the cooling circulation pipeline, and is used to reduce the temperature of the treated water and realize energy recovery through heat transfer.

[0013] In a further technical solution, a regulating tank is also included, and the regulating tank is installed between the grid filter device and the oil separator.

[0014] In a further technical solution, an activated carbon adsorption device is also included, and the activated carbon adsorption device is installed between the cooling device and the ultraviolet disinfection device.

[0015] In a further technical solution, a demulsifier dosing device is also included, and the demulsifier dosing device is installed between the oil separator and the pH value regulating device.

[0016] In a further technical solution, it also includes an air flotation device, which is installed between the flocculation reaction device and the sedimentation tank.

[0017] It is worth mentioning that the above-mentioned devices not specifically described all adopt conventional technical means in this field, which can be fully implemented by those skilled in the art, so they will not be described in detail here.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] 1. The present invention, by combining a variety of treatment processes and equipment, can efficiently and safely remove oil, organic matter and other pollutants in oily wastewater, so that the oily wastewater meets the discharge or reuse standards, and realizes the comprehensiveness and environmental protection requirements of wastewater treatment. In particular, the use of supercritical water oxidation reaction effectively removes organic matter and difficult-to-degrade substances in oily wastewater and converts them into harmless water and carbon dioxide, thereby reducing pollution to the environment and providing effective protection for the environment and human health.

[0020] 2. The present invention can use a heat recovery device to recover heat energy when the wastewater enters the cooling device for cooling, and transfer this part of the recovered heat energy to the heating system for heating the wastewater. Among them, the cooling medium used in the cooling circulation pipeline can be treated water in a qualified water temporary storage tank, which not only saves resources but also effectively utilizes the treated water. Through the action of the circulating pump, the heat transfer medium circulates between the cooling device and the heating system, thereby effectively recovering and utilizing the heat energy generated during the treatment process. This design can significantly reduce the energy consumption of the system, reduce energy consumption costs, and improve the overall energy efficiency of the wastewater treatment system. Through the application of the heat recovery device, not only the efficient utilization of energy in the wastewater treatment process is achieved, but also the effect of energy saving and emission reduction is achieved, which helps to improve the economy and environmental protection performance of the system.

[0021] 3. In the present invention, the high temperature environment and high pressure environment required for the supercritical water oxidation reaction can be adjusted according to the feedback from the sensor to ensure that effective, stable and ideal reaction conditions can be maintained during the reaction process, thereby optimizing the efficiency of the supercritical water oxidation reaction, improving the conversion rate of organic matter and difficult-to-degrade substances, and effectively removing pollutants in oily wastewater, achieving efficient, safe and environmentally friendly treatment standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0023] Figure 1 It is a system block diagram of the present invention. DETAILED DESCRIPTION

[0024] 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.

[0025] See also Figure 1 The present invention provides a coating workshop oily wastewater treatment system, comprising a wastewater collection tank, a grid filtering device, an oil separator, a pH value regulating device, a coagulation reaction device, a flocculation reaction device, a sedimentation tank, a supercritical water oxidation reactor, a cooling device, an ultraviolet disinfection device and a qualified water temporary storage tank which are sequentially connected through pipelines, the sedimentation tank is connected to a sludge treatment device, the supercritical water oxidation reactor is connected to a heating system, a pressurizing system and an oxidant supply system, which are respectively used to provide a high temperature environment, a high pressure environment and an oxidizing environment to the supercritical water oxidation reactor, the supercritical water oxidation reactor is connected to an exhaust gas emission system, the cooling device is connected to the supercritical water oxidation reactor, and is used to reduce the temperature of the treated water, and the cooling device is provided with a pressure release valve.

[0026] The specific steps to treat oily wastewater in the paint shop through this system are as follows:

[0027] The oily wastewater generated by the paint shop is first collected in the wastewater collection tank. After preliminary collection, it enters the grid filter device for coarse screening to remove larger solid particles and impurities. Subsequently, the oily wastewater flows into the grease trap, where the oil and water are separated by the difference in specific gravity. After the oily wastewater is left in the grease trap for a period of time, the oil droplets float to the water surface to form a floating oil layer, which is then removed by the oil scraper to reduce the impact of oil pollutants on subsequent treatment. The wastewater after the floating oil is removed from the grease trap then enters the pH value adjustment device. By adding an appropriate amount of chemical agents, such as sulfuric acid or lime milk, the pH value of the wastewater is adjusted to between 8 and 9, creating suitable treatment conditions for subsequent coagulation and flocculation reactions. Subsequently, the wastewater enters the coagulation reaction device and the flocculation reaction device in turn. The addition of coagulants and flocculants causes the suspended matter and dissolved matter in the wastewater to quickly aggregate and form larger flocs, which is convenient for subsequent sedimentation and separation treatment. After that, the treated water enters the sedimentation tank, and the principle of gravity sedimentation is used to make most of the floccules and other suspended solids settle to the bottom of the sedimentation tank to form a sludge layer. These sludges are usually concentrated and dehydrated through the sludge treatment device. The treated sludge is treated into solid waste and finally buried or recycled. The precipitated water enters the supercritical water oxidation reactor, and the conditions required for the supercritical water oxidation reaction are provided by the heating device, the pressurizing device and the oxidant supply device, including: temperature, usually between 374℃ (temperature above the critical point) and 700℃. The temperature and pressure conditions of supercritical water are usually above the critical point of water to ensure that the water is in a supercritical state, that is, a state between gas and liquid. Pressure, usually between 221bar (pressure above the critical point) and 280bar. High pressure conditions help maintain the supercritical state of water and enhance the reaction rate. Oxidant, usually oxygen or air is used as an oxidant, and reacts with wastewater under supercritical water conditions. According to the above reaction conditions, the wastewater is subjected to supercritical water oxidation reaction under high temperature, high pressure and oxidation environment, and the organic matter and refractory substances therein are effectively converted into harmless water and carbon dioxide, and the generated carbon dioxide is discharged through the tail gas emission system. The treated water is cooled by a cooling device, and the excess pressure is released by a pressure release valve to restore it to normal environmental conditions. Finally, the ultraviolet disinfection device is used for disinfection treatment to ensure that the water quality meets the discharge or reuse standards. After the treatment is completed, the water is collected in a qualified water temporary storage tank to wait for subsequent discharge or reuse treatment. Through the above design, the present invention can efficiently and safely remove oils, organic matter and other pollutants in oily wastewater by combining a variety of treatment processes and equipment, so that the oily wastewater meets the discharge or reuse standards, and realizes the comprehensiveness and environmental protection requirements of wastewater treatment, especially the use of supercritical water oxidation reaction, effectively removes organic matter and refractory substances in oily wastewater, and converts them into harmless water and carbon dioxide, thereby reducing pollution to the environment and providing effective protection for the environment and human health.

[0028] In a specific embodiment, the heating system includes a heater, a temperature sensor and a temperature controller, the heater is installed on the pipeline between the precipitation device and the supercritical water oxidation reactor, the temperature sensor is installed at the inlet of the supercritical water oxidation reactor, and the heater and the temperature sensor are both electrically connected to the temperature controller.

[0029] The heater and the temperature sensor are electrically connected to the temperature controller. After heating the wastewater entering the supercritical water oxidation reactor, the heating temperature can be monitored and automatically controlled in real time to ensure that effective, stable and ideal temperature conditions can be maintained during the reaction process, thereby optimizing the efficiency of the supercritical water oxidation reaction, improving the conversion rate of organic matter and difficult-to-degrade substances, and effectively removing pollutants in oily wastewater, achieving efficient, safe and environmentally friendly treatment standards.

[0030] In a specific embodiment, the pressurizing system includes a high-pressure pump, a pressure regulating valve, a pressure sensor and a high-pressure safety valve. The high-pressure pump is installed on the pipeline between the precipitation device and the supercritical water oxidation reactor. The pressure regulating valve, the pressure sensor and the high-pressure safety valve are installed in sequence on the outlet pipeline of the high-pressure pump. The high-pressure safety valve is electrically connected to the pressure sensor.

[0031] The high-pressure pump pressurizes the wastewater to the high pressure required for supercritical conditions, ensuring that the wastewater is stably transported to the supercritical water oxidation reactor, thereby maintaining the high-pressure environment required inside the reactor and improving the reaction efficiency. The combination of the pressure regulating valve and the pressure sensor can accurately monitor and adjust the pressure of the wastewater to ensure that the system operates stably within the designed operating pressure range. The high-pressure safety valve automatically releases excess pressure when the pressure exceeds the safety limit, effectively protecting the safety of equipment and operators, preventing equipment damage or safety accidents caused by overpressure, and extending the service life of the equipment and reducing maintenance costs.

[0032] In a specific embodiment, the pressurizing system further comprises a high-pressure storage tank, which is mounted on an outlet pipe of the high-pressure pump, and the pressure sensor and the high-pressure safety valve are mounted on the high-pressure storage tank.

[0033] The comprehensive use of high-pressure storage tanks, pressure sensors and high-pressure safety valves enables the high-pressure storage tanks to effectively store and stabilize wastewater, ensuring continuous supply when the supercritical water oxidation reactor needs it, and improving the stability, reliability and safety of the pressurization system during the transportation and storage of wastewater.

[0034] In a specific embodiment, the oxidant supply system includes an oxidant storage tank, a delivery pump and a flow control valve. The oxidant storage tank is connected to the supercritical water oxidation reactor through a pipeline, and the delivery pump and the flow control valve are sequentially installed on the pipeline between the oxidant storage tank and the supercritical water oxidation reactor.

[0035] The oxidant supply system ensures that the supercritical water oxidation reactor can obtain the required oxidant in a timely manner. The oxidant used here is oxygen. During the supply of the oxidant, the delivery pump can stably and continuously deliver the oxidant to the supercritical water oxidation reactor. At the same time, the flow control valve is used to accurately control the flow of the oxidant delivered to the supercritical water oxidation reactor to ensure that the supply of the oxidant is just right. In this way, the reaction conditions in the supercritical water oxidation reactor can be effectively managed and optimized, which can not only ensure that the supply of the oxidant reaches the optimal state, but also ensure that the entire reaction process is carried out under optimal conditions. Through this precise management method, the reaction efficiency and effect can be significantly improved, thereby greatly improving the overall efficiency and quality of wastewater treatment, ensuring that the treatment process is more efficient and reliable, and ultimately achieving the expected treatment goals.

[0036] In a specific embodiment, it also includes a heat recovery device, which includes a cooling circulation pipeline and a circulation pump installed on the cooling circulation pipeline. The cooling device is connected to the heating system through the cooling circulation pipeline to reduce the temperature of the treated water and realize energy recovery through heat transfer.

[0037] During the supercritical water oxidation reaction, water is in a supercritical state. After the addition of an oxidant, a strong oxidation reaction will be triggered, releasing a large amount of heat energy. Therefore, when the wastewater enters the cooling device to cool down, a heat recovery device is used to recover heat energy. The heat recovery device can transfer the recovered heat energy to the heating system to heat the wastewater. Among them, the heat transfer medium used in the cooling circulation pipeline can be treated water in a qualified water temporary storage tank, which can not only save resources but also effectively utilize the treated water. Through the action of the circulating pump, the heat transfer medium circulates between the cooling device and the heating system, thereby effectively recovering and utilizing the heat energy generated during the treatment process. This design can significantly reduce the energy consumption of the system, reduce energy consumption costs, and improve the overall energy efficiency of the wastewater treatment system. Through the application of the heat recovery device, not only the efficient use of energy in the wastewater treatment process is achieved, but also the effect of energy conservation and emission reduction is achieved, which helps to improve the economy and environmental protection performance of the system.

[0038] In a specific embodiment, it also includes a regulating tank, which is installed between the grid filtering device and the grease trap.

[0039] The regulating tank can effectively balance the water quality and flow rate entering the subsequent treatment units. In particular, the wastewater coming out of the grid filter device may have large fluctuations in concentration and particulate matter content. The regulating tank can buffer these changes and enable the subsequent treatment units to operate more stably and efficiently. In conventional technical means, an agitator is usually set inside the regulating tank to mechanically mix and treat the wastewater more evenly before entering the grease trap. This not only helps to reduce the negative impact of water quality fluctuations during wastewater treatment, but also optimizes the efficiency and effectiveness of subsequent treatment processes.

[0040] In a specific embodiment, it also includes an activated carbon adsorption device, which is installed between the cooling device and the ultraviolet disinfection device.

[0041] The activated carbon adsorption device can absorb and treat residual trace organic matter, grease and other difficult-to-degrade pollutants in the water, thereby further improving the wastewater treatment efficiency and water quality compliance rate. Since the activated carbon adsorption device is installed in the later process of the system, this design can prevent the activated carbon from being saturated or contaminated too early during the treatment process, ensuring that its adsorption capacity can be fully utilized. Through this setting, not only can the service life of the activated carbon be extended, but it can also effectively save resources and reduce treatment costs.

[0042] In a specific embodiment, it also includes a demulsifier dosing device, which is installed between the oil separator and the pH value adjusting device.

[0043] By designing a demulsifier dosing device, demulsifiers are added to break the emulsified oil droplets in the wastewater to form larger oil droplets, which are convenient for subsequent separation and treatment. This process effectively improves the emulsification state of the wastewater, making the treatment process more efficient, which is conducive to reducing the treatment cost and energy consumption in the wastewater treatment process, and improving the wastewater treatment efficiency and water quality compliance rate.

[0044] In a specific embodiment, it also includes an air flotation device, which is installed between the flocculation reaction device and the sedimentation tank.

[0045] The flotation device is installed between the flocculation reaction device and the sedimentation tank. This design helps to further improve the solid-liquid separation efficiency and quality of the sedimentation tank. The main function of the flotation device is to form a large number of tiny bubbles in the liquid by gas injection. These tiny bubbles can effectively absorb and carry suspended matter and floating matter in the wastewater, causing them to gradually float above the liquid surface, thereby achieving solid-liquid separation. In this way, not only can the purification effect of wastewater be significantly improved, but the load of the sedimentation tank can also be effectively reduced, further optimizing the treatment process.

[0046] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A coating workshop oily wastewater treatment system, characterized in that: The invention comprises a wastewater collection tank, a grid filtering device, an oil separator, a pH value regulating device, a coagulation reaction device, a flocculation reaction device, a sedimentation tank, a supercritical water oxidation reactor, a cooling device, an ultraviolet disinfection device and a qualified water temporary storage tank which are sequentially connected through pipelines. The sedimentation tank is connected with a sludge treatment device. The supercritical water oxidation reactor is connected with a heating system, a pressurizing system and an oxidant supply system, which are respectively used to provide a high-temperature environment, a high-pressure environment and an oxidizing environment for the supercritical water oxidation reactor. The supercritical water oxidation reactor is connected with a tail gas emission system. The cooling device is connected with the supercritical water oxidation reactor and is used to reduce the temperature of the treated water. The cooling device is provided with a pressure release valve.

2. A coating workshop oily wastewater treatment system according to claim 1, characterized in that: The heating system includes a heater, a temperature sensor and a temperature controller. The heater is installed on a pipeline between a precipitation device and a supercritical water oxidation reactor. The temperature sensor is installed at the inlet of the supercritical water oxidation reactor. Both the heater and the temperature sensor are electrically connected to the temperature controller.

3. A coating workshop oily wastewater treatment system according to claim 1, characterized in that: The pressurizing system includes a high-pressure pump, a pressure regulating valve, a pressure sensor and a high-pressure safety valve. The high-pressure pump is installed on a pipeline between a precipitation device and a supercritical water oxidation reactor. The pressure regulating valve, the pressure sensor and the high-pressure safety valve are installed in sequence on an outlet pipeline of the high-pressure pump. The high-pressure safety valve is electrically connected to the pressure sensor.

4. A coating workshop oily wastewater treatment system according to claim 3, characterized in that: The pressurizing system further comprises a high-pressure storage tank, which is mounted on an outlet pipe of the high-pressure pump, and the pressure sensor and the high-pressure safety valve are mounted on the high-pressure storage tank.

5. The oily wastewater treatment system of a painting workshop according to claim 1 is characterized in that: The oxidant supply system includes an oxidant storage tank, a delivery pump and a flow control valve. The oxidant storage tank is connected to the supercritical water oxidation reactor through a pipeline. The delivery pump and the flow control valve are sequentially installed on the pipeline between the oxidant storage tank and the supercritical water oxidation reactor.

6. A coating workshop oily wastewater treatment system according to claim 1, characterized in that: It also includes a heat recovery device, which includes a cooling circulation pipeline and a circulation pump installed on the cooling circulation pipeline. The cooling device is connected to the heating system through the cooling circulation pipeline to reduce the temperature of the treated water and realize energy recovery through heat transfer.

7. The oily wastewater treatment system of a painting workshop according to claim 1 is characterized in that: It also includes a regulating tank, which is installed between the grid filtering device and the oil separator.

8. The oily wastewater treatment system of a painting workshop according to claim 1 is characterized in that: It also includes an activated carbon adsorption device, which is installed between the cooling device and the ultraviolet disinfection device.

9. The oily wastewater treatment system of a painting workshop according to claim 1 is characterized in that: It also includes a demulsifier dosing device, which is installed between the oil separator and the pH value regulating device.

10. The oily wastewater treatment system of a painting workshop according to claim 1, characterized in that: It also includes an air flotation device, which is installed between the flocculation reaction device and the sedimentation tank.

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