Supercritical carbon dioxide cleaning device for coating spraying pipeline

Abstract

The utility model belongs to the technical field of coating spraying pipeline cleaning, and particularly relates to a supercritical carbon dioxide cleaning device for a coating spraying pipeline. The device comprises a supercritical carbon dioxide cleaning agent blending device and a supercritical carbon dioxide cleaning agent regenerating device, the supercritical carbon dioxide cleaning agent blending device comprises a carbon dioxide steel cylinder, a cleaning agent storage tank, a booster pump, a heat exchanger, a pressure meter, a magnetic liquid level meter and the like. The supercritical carbon dioxide cleaning agent regeneration device comprises a buffer tank, a gas-liquid separation tank, a vacuum pump, a pressure gauge and the like. Supercritical carbon dioxide is added into a cleaning agent, so that the use amount of a cleaning solvent is reduced, and the purpose of cleaning a pipeline and a pump body can be achieved; in the whole cleaning process, near zero emission of VOCs is achieved, and the health risk caused by the fact that an operator is exposed in a high-VOCs atmosphere due to pipeline cleaning is avoided; in addition, heat generated by the device can be fully utilized to reach the supercritical state of carbon dioxide, and operation energy consumption is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of paint spraying pipeline cleaning, and in particular relates to a paint spraying pipeline supercritical carbon dioxide cleaning device. Background Art

[0002] In recent years, under the influence and promotion of various environmental protection policies, water-based paints have been vigorously promoted, but the use and market share of solvent-based paints still reach about 70%. In the coating application process, in order to meet consumers' demand for coating performance and color personalization of home, automobile and personal consumer products, manufacturers have to frequently change coatings of different colors and performances for coating. Therefore, the paint pipeline needs to be cleaned with a large amount of solvent diluent, which increases the generation of hazardous waste on the one hand, and inevitably emits VOCs into the surrounding atmosphere on the other hand, which also affects the health of operators.

[0003] Supercritical fluid technology has the characteristics of simple operation, high efficiency and no pollution, and is widely used in flavors and fragrances, pharmaceuticals, petroleum, environmental protection, etc. Carbon dioxide can reach a supercritical state under the conditions of a temperature of 31.26°C and a pressure of 7.38Mpa, which reduces the difficulty of equipment manufacturing. In the supercritical state, it has high density, strong permeability, excellent solubility and viscosity, making it a very potential environmentally friendly cleaning technology.

[0004] Patent CN215613770U discloses a liquid carbon dioxide cleaning machine, which uses liquid carbon dioxide to be accelerated by nitrogen to be discharged from the spray gun, forming tiny solid carbon dioxide in the shape of snowflakes to clean precision components, but cannot clean the spray pipeline. Patent CN107971299A discloses a supercritical carbon dioxide cleaning device and a cleaning method thereof, which includes cleaning, heating, cooling, pressure supply, carbon dioxide supply, collection and other mechanisms. The patent has a cleaning kettle, which is suitable for cleaning small objects, but cannot clean the spray pipeline.

[0005] The utility model provides a supercritical carbon dioxide cleaning device for spraying pipelines, which solves the current situation of using a large amount of solvent to clean pipelines due to frequent color changes during the painting process, and makes VOCs emission reach near zero, and reduces the amount of hazardous waste. At the same time, this method reuses the heat generated by the booster pump to achieve supercriticality, reduces equipment investment and energy consumption, and realizes CO 2 The cleaning solvent can be reused to ensure zero pollution to the environment during the entire cleaning process. Summary of the invention

[0006] The utility model aims to provide a supercritical carbon dioxide cleaning device for paint spraying pipelines with low energy consumption and high efficiency, which can realize the cleaning of spraying pipelines while reducing the use of original cleaning solvents, and achieve supercritical by utilizing the heat generated by pressurized carbon dioxide, thereby reducing equipment investment and energy consumption. In addition, the gas-liquid separation tank is used to realize CO 2 And the function of recycling cleaning solvent.

[0007] The utility model provides a supercritical carbon dioxide cleaning device for a paint spraying pipeline, the structure of which includes: a supercritical carbon dioxide cleaning agent mixing device and a supercritical carbon dioxide cleaning agent regeneration device; wherein:

[0008] The supercritical carbon dioxide cleaning agent preparation device comprises: a carbon dioxide cylinder 1, a cleaning agent storage tank 9, a booster pump 10, a heat exchanger, a first adapter 27, a first pressure gauge 8, and a magnetic level gauge 3;

[0009] The supercritical carbon dioxide cleaning agent regeneration device comprises: a buffer tank 19, a gas-liquid separation tank 15, a vacuum pump 16, a second adapter 11, a second pressure gauge 14, and a third pressure gauge 17;

[0010] In the cleaning agent preparation device, two valves are provided at the inlet of the booster pump 10, one of which is CO 2 Valve 2 is connected to the carbon dioxide cylinder 1, and another buffer tank valve 22 is connected to the buffer tank 19; when the cleaning agent is prepared, the valve 2 connected to the buffer tank 19 is in a closed state.

[0011] In the cleaning agent dispensing device, the heat exchanger is composed of a heat exchange plate 20 and a heat exchange pump 21; the heat exchange plate 20 is connected to the heat exchange pump 21, and the heat exchange pump 21 is connected to the pump body of the booster pump 10. The heat exchange plate 20 is arranged at the bottom of the cleaning agent storage tank 9. The outlet of the booster pump 10 is connected to the upper part of the side of the tank body of the cleaning agent storage tank 9 through a valve 28. A first pressure gauge 8 is arranged on the top of the cleaning agent storage tank 9, and a magnetic level gauge 3 is connected to the other side of the tank body of the cleaning agent storage tank 9; a cleaning agent injection port 5 is arranged on the top of the cleaning agent storage tank 9, and the lower part of the outlet pipe of the cleaning agent storage tank 9 is inserted into the bottom of the tank body, and the upper part is provided with a sealing flange 7, a valve 26 and a adapter 27 for connection.

[0012] In the cleaning agent regeneration device, the gas-liquid separation tank 15 is cylindrical in the upper part and conical in the lower part. The inlet of the gas-liquid separation tank 15 is connected to the valve 12 and the adapter 11. The second pressure gauge 14 is placed on the top of the gas-liquid separation tank 15. The outlet of the gas-liquid separation tank 15 is connected to the inlet of the vacuum pump 16 through the connecting valve. The outlet of the vacuum pump 16 is connected to the lower side of the buffer tank 19 through the valve 23. The top of the buffer tank 19 is connected to the third pressure gauge 17. The outlet of the buffer tank 19 is connected to the valve of the main pipeline of the booster pump 10. The gas-liquid separation tank 15 is equipped with an evaporation sheet 25, which is connected to the temperature control heater 29. The conical bottom of the gas-liquid separation tank 15 is connected to the slag discharge valve 18.

[0013] The feed port of the cleaned airless spray plunger pump 6 is connected to the adapter 27 of the cleaning agent storage tank 9 , and the discharge port is connected to the adapter 11 of the gas-liquid separation tank 15 .

[0014] Furthermore, in the present invention:

[0015] The volumes of the cleaning agent storage tank 9, the gas-liquid separation tank 15 and the buffer tank 19 do not exceed 25L.

[0016] The booster pump 10 is one of a screw pump, a plunger pump, and a reciprocating pump, with a boost pressure range of 0-40 MPa and a flow rate of 1-5 L / min.

[0017] The cleaning agent storage tank 9 is provided with a heat-insulating cotton 4 for heat preservation. The cleaning agent storage tank 9 is provided with a magnetic level gauge 3.

[0018] The adapter 11 is used to connect the feed pipe to be cleaned and sprayed and the paint discharge pipe after the spray gun is removed.

[0019] The gas-liquid separation tank 15 contains stainless steel heating plates (3-50 plates), each plate is 3-5 mm thick, and the interval between plates is 1-5 mm.

[0020] The vacuum pump 16 is an oil-free vertical reciprocating vacuum pump with a limit vacuum degree of 200-2000 Pa and a pumping speed of 31-158 L / min.

[0021] The flow rate of the heat exchanger is 1-3 L / min. The heat exchange medium is water, refrigerant, and dimethyl silicone oil.

[0022] The heat exchange fin area in the cleaning agent storage tank 9 is 1-10m 2 , made of carbon steel, 304 stainless steel or 316L stainless steel.

[0023] The cleaning device of the utility model has a fully enclosed cleaning process, which can reduce the volatilization of VOCs. The cleaning agent and carbon dioxide are recycled and reused through the gas-liquid recovery device. In addition, supercritical carbon dioxide is added as a solvent to reduce the amount of cleaning agent used. Finally, the supercriticality is achieved by utilizing the heat of the pump body during its own pressurization process, thereby reducing unnecessary energy consumption.

[0024] The working process of the cleaning device of the utility model is as follows:

[0025] (1) First, remove the spray gun of the airless spray equipment to be cleaned, connect the suction inlet pipe of the airless spray equipment to the cleaning agent storage tank 9, and connect the paint outlet pipe to the gas-liquid separation tank 15.

[0026] (2) By observing the liquid level gauge 3, 6-15 liters of cleaning agent is injected into the cleaning agent storage tank 9 and overflows the heat exchanger fins 20 in the cleaning tank. Then the feed port is closed, the carbon dioxide cylinder 1 is opened, and high-pressure liquefied carbon dioxide is injected into the cleaning agent storage tank 9 through the booster pump 10. The liquid level gauge 3 is observed to control the injection amount of carbon dioxide to 5-14 liters. The booster pump 10 transfers the heat of the pump body during the boosting process to the cleaning agent storage tank 9 through the heat exchanger. When the cleaning agent storage tank 9 reaches the required 10-20 liters, pressure 7.5-15 MPa, and temperature 32-60°C, the cleaning agent storage tank reaches the cleaning state.

[0027] (3) Open the pipe valve connected to the suction port of the airless spray equipment (airless spray plunger pump 6), introduce the cleaning agent containing supercritical carbon dioxide into the pump body and pipeline of the airless spray equipment, wait for 1-10 minutes to allow the residual paint in the pump body and pipeline to be fully dissolved in the cleaning agent containing supercritical carbon dioxide, then open the valves of the gas-liquid separation tank 15 and the airless spray nozzle outlet, at this time, a large amount of cleaning solvent and supercritical carbon dioxide are sprayed into the gas-liquid separation tank 15, and after reaching pressure balance, close the cleaning tank outlet valve.

[0028] (4) The temperature of the stainless steel sheet in the gas-liquid separation tank 15 is controlled in advance between 30-120°C, and the mixed waste liquid flowing through is instantly heated. The vacuum pump 16 is turned on, and the outlet valve at the top of the gas-liquid separation tank 15 is opened. The cleaning agent and carbon dioxide in the mixed waste liquid in the gas-liquid separation tank 15 that are vaporized due to heat absorption are pumped into the buffer tank 19 through the vacuum pump 16, and the gas-liquid separation tank 15 is formed into a vacuum state, and the vacuum degree is maintained at 200-2000 Pa. The cleaning solvent and carbon dioxide in the mixed waste liquid are extracted as much as possible through reduced pressure distillation.

[0029] (5) Turn on the booster pump 10, open the valve connected to the cleaning agent storage tank 9, pressurize and liquefy the carbon dioxide and cleaning agent in the buffer tank 19, and then transport them to the cleaning agent storage tank 9, so as to achieve the purpose of recycling and reuse.

[0030] (6) After the cleaning process is completed, the next cleaning is carried out. After repeated cycles of 2-5 times, the cleaning work of the airless spray equipment can be completed. After the work is completed, under the condition that there is no pressure difference in the gas-liquid separation tank, the slag discharge valve 18 is opened to discharge the cleaned paint waste residue.

[0031] The utility model reduces the amount of solvent used in the traditional cleaning process by adding supercritical carbon dioxide to the cleaning agent, and achieves the purpose of cleaning the pipeline and the pump body. In addition, VOCs are emitted nearly zero during the entire cleaning process, avoiding the health risks brought by operators being exposed to a high-VOCs atmosphere due to repeated cleaning of the pipeline during the traditional cleaning process. Finally, the heat generated by the equipment itself is fully utilized to achieve the supercritical state of carbon dioxide, thereby reducing operating energy consumption, enhancing the economy of the device, and reflecting good market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the structure of the supercritical carbon dioxide cleaning equipment for paint spraying pipelines of the utility model.

[0033] Number in the figure: 1-CO 2 Cylinder, 2-CO 2 Valve, 3-level gauge, 4-insulation cotton, 5-solvent injection port, 6-airless spray plunger pump, 7-sealing flange, 8-first pressure gauge, 9-cleaning agent storage tank, 10-boosting pump, 11-adapter, 12-valve, 13-valve, 14-second pressure gauge, 15-gas-liquid separation tank, 16-vacuum pump, 17-third pressure gauge, 18-slag discharge valve, 19-buffer tank, 20-heat exchange plate, 21-heat exchange pump, 22-valve, 23-Y-type switching valve, 24-suction pipe, 25-evaporation plate, 26-valve, 27-adapter, 28-check valve, 29-thermostat. DETAILED DESCRIPTION

[0034] The present invention will be further described below by way of embodiments in conjunction with the accompanying drawings.

[0035] Before cleaning, empty the paint in the airless spray plunger pump 6 and the pipeline, remove the spray gun, connect the spray pipeline to be cleaned to the inlet valve 12 of the gas-liquid separation tank through the adapter 11, and close the valve 12, valve 22 and slag discharge valve 18. Connect the airless spray suction pipe 24 to the outlet valve 26 of the cleaning agent storage tank through the adapter 27, seal the pipeline through the flange 7, add 12 liters of cleaning agent from the injection port 5 and seal it. The amount of cleaning agent added can be obtained through the liquid level meter 3. Turn on the CO 2 Cylinder valve 2, CO 2 From CO 2Carbon dioxide flows out of cylinder 1 and is injected into cleaning agent storage tank 9 through booster pump 10. Since pressurization and liquefaction is an exothermic process, the heat of the pump body of booster pump 10 is removed through heat exchange pump 21 and heat exchanger 20, and the cleaning agent in cleaning tank 9 is heated. Observe the first pressure gauge 8 and liquid level gauge 3, and adjust the CO 2 The amount of added is to make the liquid level in the cleaning tank reach 20L. When the pressure reaches 8Mpa and the temperature reaches 35°C, the cleaning agent tank is configured with a supercritical carbon dioxide cleaning agent to be used.

[0036] Open CO 2 The exhaust valve 13 and the switch Y-type valve 23 are switched to the exhaust pipe, and the vacuum pump 16 is started. After the air in the gas-liquid separator 15 is exhausted, it is switched to the buffer tank 19 through the Y-type valve 23. The cleaning agent inlet valve 12 is opened. Due to the operation of the vacuum pump 16, the airless spray pipeline to be cleaned is in a negative pressure state. Then the valve 12 is closed, the cleaning agent tank valve 26 is opened, and the airless spray plunger pump 6 is started. Under the pressure difference, the supercritical carbon dioxide cleaning agent instantly fills the entire pipeline to be cleaned and remains stationary for 10 minutes. After waiting for the paint in the pipe to be fully dissolved, the valve 12 is opened, and the cleaning agent entrains supercritical carbon dioxide and is sprayed into the gas-liquid separation tank 15. The cleaning waste liquid flows through the stainless steel sheet 25 heated to 70°C by the heater 29. By observing the second pressure gauge 14, when the pressure reaches 1 MPa, close the valve 12, and open the vacuum pump 16 and valve 13 to pump the mixed steam of carbon dioxide and cleaning agent in the gas-liquid separation tank 15 to the buffer tank 19, close the valve 2, start the pressure pump 10, pressurize and liquefy the separated mixed steam, and then transport it to the cleaning agent tank 9 through the one-way valve 28. Through multiple cleaning cycles, the purpose of cleaning the airless spray pump and pipeline is finally achieved. After multiple cleanings, under the condition of ensuring that there is no pressure difference in the gas-liquid separation tank, open the slag discharge valve 18 to discharge the cleaned paint waste residue.

[0037] The utility model can reduce the usage of cleaning agent by 40%, realize the recovery and reuse of cleaning agent, and achieve near-zero emission of VOCs in the cleaning process.

[0038] The above is only the preferred embodiment of the utility model, and does not limit the utility model in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the technical solution of the utility model still belongs to the protection scope of the technical solution of the utility model.

Claims

1. A supercritical carbon dioxide cleaning device for paint spraying pipelines, characterized in that: The structure includes: Supercritical carbon dioxide cleaning agent preparation device, supercritical carbon dioxide cleaning agent regeneration device; wherein: The supercritical carbon dioxide cleaning agent preparation device comprises: a carbon dioxide cylinder, a cleaning agent storage tank, a booster pump, a heat exchanger, a first adapter, a first pressure gauge, and a magnetic level gauge; The supercritical carbon dioxide cleaning agent regeneration device comprises: a buffer tank, a gas-liquid separation tank, a vacuum pump, a second adapter, a second pressure gauge, and a third pressure gauge; In the supercritical carbon dioxide cleaning agent preparation device, the inlet of the booster pump is provided with two valves, one of which is a CO2 valve connected to the carbon dioxide cylinder, and the other is a buffer tank valve connected to the buffer tank; when the cleaning agent is prepared, the CO2 valve connected to the buffer tank is in a closed state; the heat exchanger is composed of a heat exchange plate and a heat exchange pump; the heat exchange plate is connected to the heat exchange pump, and the heat exchange pump is connected to the booster pump; the heat exchange plate is arranged at the bottom of the cleaning agent storage tank; the outlet of the booster pump is connected to the upper side of the cleaning agent storage tank body through a valve; a first pressure gauge is arranged on the top of the cleaning agent storage tank, and a magnetic level gauge is connected to the other side of the cleaning agent storage tank body; a cleaning agent injection port is arranged on the top of the cleaning agent storage tank, the lower part of the cleaning agent storage tank outlet pipe is inserted into the bottom of the tank body, and the upper part is provided with a sealing flange, a valve and connected to the first adapter; In the supercritical carbon dioxide cleaning agent regeneration device, the upper part of the gas-liquid separation tank is cylindrical, and the lower part is conical. The inlet of the gas-liquid separation tank is connected to the valve and the second adapter. The second pressure gauge is placed on the top of the gas-liquid separation tank. The outlet of the gas-liquid separation tank is connected to the inlet of the vacuum pump through the valve. The outlet of the vacuum pump is connected to the lower side of the buffer tank through the valve. The top of the buffer tank is connected to the third pressure gauge. The outlet of the buffer tank is connected to the valve of the booster pump main pipeline. The gas-liquid separation tank is equipped with an evaporating plate, which is connected to the temperature control heater. The conical bottom of the gas-liquid separation tank is connected to the slag discharge valve. The feed inlet of the cleaned airless spray equipment is connected to the first adapter of the cleaning agent storage tank, and the discharge port is connected to the second adapter of the gas-liquid separation tank.

2. The paint spray pipeline supercritical carbon dioxide cleaning device according to claim 1 is characterized in that: The volumes of the cleaning agent storage tank, gas-liquid separation tank and buffer tank do not exceed 25L.

3. The paint spraying pipeline supercritical carbon dioxide cleaning device according to claim 1 is characterized in that: The booster pump is one of a screw pump, a plunger pump and a reciprocating pump.

4. The paint spray pipeline supercritical carbon dioxide cleaning device according to claim 1 is characterized in that: The cleaning agent storage tank is provided with heat-insulating cotton for heat preservation.

5. The paint spray pipeline supercritical carbon dioxide cleaning device according to claim 1 is characterized in that: The gas-liquid separation tank is provided with 3-50 stainless steel heating plates, each of which is 3-5 mm thick and the interval between the plates is 1-5 mm.

6. The paint spray pipeline supercritical carbon dioxide cleaning device according to claim 1 is characterized in that: The vacuum pump is an oil-free vertical reciprocating vacuum pump.

7. The paint spray pipeline supercritical carbon dioxide cleaning device according to claim 1 is characterized in that: The heat exchanger area in the cleaning agent storage tank is 1-10m 2 .

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