Views:15 Author:China Xicheng Publish Time: 2021-07-12 Origin:China Xicheng
The components of waste gas produced in the treatment of printing waste gas:
Printing waste gas is mainly the ink waste gas generated during printing and the waste gas volatilized from the gasoline used to clean the ink stick.
The printing of the project uses water-based ink, and the printing waste gas comes from:
(A) A small amount of ink waste gas volatilized during printing. This part of the waste gas has a small volatilization amount. The main component is low-grade hydrocarbons and does not contain harmful components such as benzene and toluene. The amount generated is calculated at 10% of the ink consumption, and the emission amount is 0.3t/ a;
(B) Clean up the exhaust gas volatilized from the gasoline used in the ink stick and the printing plate. Volatile gasoline is based on non-methane total hydrocarbons. The consumption is only 0.6 t/a, the volatilization is calculated at 5%, and the emission is 0.03t/a.
The maximum allowable emission concentration of non-methane total hydrocarbons: 120mg/m3, emission rate 10kg/h (15m exhaust cylinder.
Generally, the exhaust gas produced by ink is mainly non-methane total hydrocarbon organic matter produced by the volatilization of ink diluent. For the dust in the ink, carbon black should be used as the control index of the pollution factor. PM10 considers and pays attention to governance measures.
Generally speaking, ink diluents can be divided into two types, the ratio of the components of the two diluents:
1. Banana water: ingredients are 5% butanol, 21% toluene, 5% xylene, 15% butyl acetate, 12% ethyl acetate
2. Thinner water is mainly composed of ethyl acetate, n-butyl acetate, n-butanol, acetone, benzene and xylene, etc., and methyl ethyl ketone is used as a solvent. The role of the resin vinyl chloride-vinyl acetate copolymer is that it will not be diluted after dilution. Reduce the viscosity of the ink and the printed matter to ensure the printing fastness.
The solvent-based ink used in the production process of the traditional packaging and printing industry, the ink contains 50%-60% of volatile components; the diluent required to adjust the ink viscosity increases the emission of organic waste gas. When the printed product is drying, the total content of volatile components emitted by the ink accounts for 70%-80%, and a large amount of ethanol, ethyl acetate, butyl acetate, propyl acetate, toluene, xylene and other organic gases will be volatile and discharged. , It is very harmful to the surrounding environment and human health.
Printing waste gas (VOCS waste gas) treatment plan:
VOCs waste gas comes from the ink and thinner used in the printing process, composite adhesives and equipment cleaning agents. There are 5 ways to discharge VOCS waste gas: solvent volatilization in the ink blending process, ink solvent volatilization in the printing process, drying stage, and composite process And equipment cleaning process, etc. The inks used by lithographic printing companies include solvent-based inks, vegetable soybean inks, UV-curable inks and water-based inks. Solvent-based inks contain high volatile organic compounds and are the main source of VOCs for lithographic printing companies. In addition, the organic solvent-based car wash water and fountain solution used in the production process of traditional lithography are also one of the emission sources of VOCs.
Regarding the VOCS waste gas generated in printing, the usual printing waste gas treatment solutions include: catalytic combustion method-rto waste gas treatment equipment (but the initial investment cost is too high and the area is large), PP wet scrubber system + UV+PP activated carbon tower Treatment method, this method is a commonly used waste gas treatment equipment in VOCS waste gas treatment engineering, and it is cost-effective.