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Waste treatment methods in coating production

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  waste disposal
  The pollution of painting production line generally includes waste gas, waste water, waste residue and noise. At present, the exhaust gas of coating production line in China mainly comes from the exhaust gas from pretreatment, spray painting room, leveling room and drying furnace, and the pollutants discharged are generally as follows: organic solvent that can form photochemical smog, volatile matter of paint discharged, thermal decomposition products and reaction products, acid-base mist, dust generated during shot peening and dust in paint mist. It is the most effective way to solve the problem of organic solvent pollution by using coatings without organic solvent or low organic solvent content. The amount of organic solvent should be reduced as much as possible, and the waste gas containing high concentration of organic solvent should be treated in a centralized way The waste gas of organic solvent with high concentration and small air volume from the drying and curing furnace in the production line is usually treated by combustion method, catalytic combustion method and adsorption method.
  The wastewater mainly comes from degreasing, phosphating and passivation wastewater produced by coating pretreatment, and wastewater containing electrophoretic paint produced by cathodic electrophoresis. The waste water from the spray booth and cleaning of water-based medium coating, and the waste water discharged regularly by the circulating water of the top paint spraying room. Generally, all the wastewater is concentrated in the basement and treated according to the type of sewage. The wastewater containing acid and alkali is neutralized, precipitated, filtered and discharged; the wastewater containing 6 valent chromium (Cr6 -) is treated by electrolysis and chemical reduction methods; the paint mist coagulant is added to the paint spray room wastewater, whether it is water-borne paint or solvent based paint, and the paint residue is automatically discharged. The treated wastewater can be recycled, and the paint residue is burned or mixed with other industrial wastes Dispose of the material together.
  Iwatera is mainly composed of cationic polymer with medium molecular weight and high charge. It has a strong attraction to the paint drops. When the paint drops are "captured" and absorbed, it can completely wrap the paint drops with different polarity affinity, penetrate the paint drops, destroy the functional groups of the coating, completely eliminate the viscosity, and drive the coated and broken paint drops to float. Iwaterb is mainly composed of polymer with molecular weight of tens of millions. Through the "bridge" action between molecules, iwaterb gathers the damaged paint mist and impurities into larger groups, making it firm and adhesive, and enhancing the efficiency of mechanical dehydration. The flocculant can also neutralize the system charge, keep the ion balance in the system, and the molecular weight is large, so that the agglomerating group floats faster in the system, and forms paint residue to float on the water surface.
  The waste residue is mainly the sediment produced by paint residue and wastewater treatment. Generally, the water quality can be removed by plate and frame filter press and transported to the special waste residue storage area.
  The noise source mainly comes from the fan and the transportation device, so we must select the fan and transport device that meet the noise requirements in the production line, and it is better to set up sound-absorbing materials inside the coating workshop. With the development of the times, the control system of painting production line has been improved, and the control system is required to be more and more reliable. Therefore, the electrical control of the coating production line is generally a multiple control, which can be controlled by each electrical cabinet or by the central room. The central control room and the drying channel are generally equipped with microcomputers, which can accurately control the temperature of each zone of the drying and curing furnace body. The central control room can be equipped with a TV monitor to display and record the temperature rise and fall curve, and can also set and modify parameters at any time, so as to adjust the parameters according to various working conditions Adjust the temperature according to the size and color of the parts. The bath liquid can be controlled by thermocouple. In general, all motors in the coating production line are equipped with double protection and interlock with the main control. In case of any motor failure, the sub control cabinet and the central control room can give an alarm. If the equipment fails, the whole line can stop automatically to ensure the operation safety

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