How to treat VOCs for water-based coatings and oily coatings

In order to explore the harm of volatile organic compounds in water-based coatings, it is necessary to grasp the meaning and characteristics of water-based coatings and volatile organic compounds. The water-based coatings described in this paper refer to all coatings that use water as solvents or as dispersing media. At present, it is also considered to be a relatively new coating in the paint market, the reason why this coating is widely used, because the coating has a good surface adaptability, strong coating adhesion, parallel is better, can save a lot of resources, but also reduce atmospheric environmental pollution and other advantages, therefore, water-based coatings may be an important development direction of the future paint market, its research is very necessary.the World Health Organization defines volatile organic compounds as volatile organic compounds between the boiling point
50
degrees C and
260
degrees C at room temperature. According to its chemical structure, it can be divided into alkanes, aromatics, esters, aldehydes and other types. At present, there are more than 300 species
identified,
number is quite amazing. Indoors, high concentrations of volatile organic compounds will cause many safety problems, the most likely is to cause acute poisoning, to a higher degree may be serious to the coma, convulsions and even damage to the internal organs, brain and nervous system, resulting in the loss of memory and other serious consequences of the human brain. Heavy people are also likely to have liver poisoning or even cause people to be in a coma, bringing life-threatening, these hazards can not be ignored.。 (See all picture news on China Coatings Online)
The harm of volatile organic matter in water-based coatings In recent years, with the continuous development of the decoration market, consumers for all kinds of increasing demand, producers in order to meet the needs of consumers ignored a variety of preventive measures, resulting in more and more problems in furniture, in these ensuing problems, indoor environmental pollution is particularly important, because indoor environmental pollution has endangered the health of the human body, but also more and more attention to the concept of mass consumption. Now consumers with the decoration process of a variety of colors of brightness matching have high requirements, and water-based coatings are able to meet consumer demand for one of the important elements, in water-based coatings contain a variety of volatile organic compounds, these organic compounds are components of: hydrocarbons, halogenated hydrocarbons, nitrogen hydrocarbons and oxygen hydrocarbons, which contain a variety of compounds, these compounds in addition to heavy metals, but also formaldehyde, glycol, ammonia and other volatile organic compounds. Once people live in a room filled with too many of these substances, the consequences can be unimaginable. So, in the face of such both demand and harm, what should we do? The author believes that although such harm can not be said to be completely eliminated, but it can be prevented and controlled, as far as possible to minimize the danger can learn from the following methods.In the past two years in the environmental protection emission reduction requirements, water-based paint in our surface coating construction more and more use, water-based paint as the name implies is a coating that can dissolve in water, and oily paint is solvent-based paint through the hydrochron mound and water curtain cabinet when not dissolved in water, is suspended or diffused in water; Suspended or diffused in water also produces wastewater, but the two wastewater treatment process and treatment principles are different, oily coating wastewater treatment is filtering filter, is a mature physical process, is better to treat, and water-based paint wastewater dissolved in water, the current treatment of this wastewater physical process is membrane reverse osmosis process, membrane reverse osmosis process is more complex and very high cost, if the chemical method costs higher and bring a lot of trouble. That is to say, the coating process uses water-based paint, the coating room should use dry spraying process, the discharge port using dry filtration intercept, the paint spray paint fog in the solid substances, such as pigments, titanium dioxide, liquid substances such as water-based resin official energy group completely intercepted, emissions of exhaust gas non-methane total hydrocarbon content will be less than
20mg/m
33
,
because water-based paint thinners
80%
water, good water-based coatings
95%
water.
20%-5%
solvents are alcohols and a small number of ethers and very few additives, additives are designed to change the surface strength of water-based resins and increase the adhesion of water-based coatings. Therefore, it is recommended that the enterprise coating line preparing to use water-based paint should be built dry coating line later. Primer, midway through, color paint line considers not using zeolite wheel, in order to reduce losses when changing water-based coatings. The hood varnish line considers the zeolite wheel, as the surface hood varnish cannot be water-like varnish in a short period of time.In order to reduce construction costs and equipment volume dry spraying is the direction of development, in order to meet the current environmental protection situation of the coating exhaust gas treatment pre-treatment is completely the most important, and the choice of treatment equipment is not the best, only the most reasonable. Enterprises have the conditions to do automatic spraying, must do backwind treatment, and backwind treatment pre-treatment also needs to be completely resolved. In addition, in the process of coating exhaust gas treatment, in order to further reduce wind resistance, pipe arrangement, fan selection, the coating process of whether the product meets the production requirements play a role in determining, so the layout of the pipeline, fan selection must be carefully calculated carefully selected.(view all pictures of China Paint Online News)paint fog separation technology equipment device diagram, the figure can be seen, exhaust gas first in the contact area and the generator produced micron bubble contact, all hydrophobic substances will be adsorbed to the surface of the micro-bubble, and then the gas rising into the upper and lower reaction zone, in the reaction area micro-bubbles will continue to break, release a certain amount of instantaneous energy to make the solvent volatile, and resin and other sinking and further polymerization drying. Since the polymerized polymerized polymer resin is almost insoluble in water, the circulating water in the reservoir is not contaminated, just regularly recycling the resins that are deposited in it. The exhaust gas with machine solvent after the resin is removed passes through the filter tank and proceeds to the next process to continue processing.。 (See all picture news on China Paints Online)
Paint fog separation technology effect and characteristics coating paint exhaust gas discharge port direct docking this equipment, is the whole set of
VOCs
treatment program of the forward army, exhaust gas after the paint mist separation equipment, the gas with viscous paint mist is removed, general Paint mist removal rate of
95%
or more, the larger viscosity of
UV
paint removal rate can also ensure
85% or more
, followed by simple dry filtration can ensure the normal operation of the post-treatment process.this paint mist separation technology is different from other traditional technologies on the market, its characteristics include: (1) complete separation of viscous resin from organic solvents, viscous resin insevent after non-viscosity, easy to collect. (2) The equipment maintenance is simple, the system has no fillers, the operating cost is low, no chemical agents are added, no secondary pollution and other consumables. (3) Powder coating powder collection can be achieved recovery.
。