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Organic Emission Reduction Preliminary Study On Emission Reduction Management Of Volatile Organic Compounds In Printing Industry
- May 28, 2018 -

Volatile organic compounds, VOCs (Volatile Organic Compounds), refer literally to volatile organics under certain conditions. Volatile organic compounds have a certain impact on human health and the environment. There are several definitions based on the impact and the control object. For example, the US ASTM D3960-98 standard defines VOCs as any organic compound that can participate in atmospheric photochemical reactions. The definition of the US Federal Environmental Protection Agency (EPA): Volatile organic compounds are carbon compounds that participate in atmospheric photochemical reactions except CO, CO2, H2CO3, metal carbides, metal carbonates, and ammonium carbonate. The definition of total volatile organic compounds (TVOCs) by the World Health Organization (WHO, 1989) is the general term for volatile organic compounds with a melting point below room temperature and a boiling point between 50°C and 260°C. The definitions of VOCs in the international standards ISO 4618/1-1998 and DIN 55649-2000 of the general terms for colour paints and varnishes are: In principle, any organic liquids and/or solids that can self-generate under normal temperature and pressure. At the same time, the German DIN 55649-2000 standard, when determining the content of VOCs, has also made a limitation that any organic compound with a boiling point or initial boiling point lower than or equal to 250°C under normal pressure conditions.

In terms of environmental protection, VOCs are key preconditions for PM2.5 and O3 pollution. Therefore, the purpose of defining VOCs is very clear, in order to control air pollution, the definition of VOCs in China is not the same, but the basic principle is the same, with reference to the Shanghai "Integrated Emission Standard for Air Pollutants" (DB31/933-2015) Definitions: Organic compounds that participate in atmospheric photochemical reactions or determined or calculated organic compounds according to prescribed methods. VOCs used for accounting or filing refer to organic compounds with a saturated vapor pressure of not less than 10 Pa at 20°C or a boiling point of 260°C at 101.325 KPa standard atmospheric pressure (or organic substances with corresponding volatility under actual production conditions) except methane, The content of non-methane hydrocarbon (NMHC, Non-MethaneHydroCarbon) was used as a detection and control index.

The printing industry uses a lot of inks, thinners, fountain solutions, adhesives, coating solutions, varnish, car wash water, etc. in the production process. These raw and auxiliary materials basically contain organic solvents that meet the definition of VOCs and are used in the production process. Emissions to the atmosphere, therefore also as a key industry controlled by VOCs. 

According to actual measurement data from the Shanghai Research Institute of Environmental Sciences, typical plastic film solvent-type gravure discharge outlets have untreated exhaust VOCs (characterized by NMHC) of 300 to 600 mg/m3; typical dry compound discharges are untreated exhaust gas. VOCs (characterized by NMHC) even reach 3500mg/m3; typical sheet-fed offset discharge untreated exhaust VOCs (characterized by NMHC) 30 to 100mg/m3; typical aqueous flexo discharge untreated exhaust VOCs ( Characterized by NMHC: 10~50mg/m3 (Referring to the Shanghai Municipal Standard for Emission of Air Pollutants in the Printing Industry (DB31/872-2014), NMHC emission limit is 50mg/m3.)

With the advancement of VOCs emission reduction work, local governments have successively issued corresponding control policies for the management and control of VOCs emissions from the printing industry.

1 Formulate VOCs emission standards and VOCs emission reduction technical specifications

Up to now, Guangdong, Beijing, Shanghai, Tianjin, Sichuan, Chongqing, Hebei, and Shandong have all introduced local printing or related emission standards. The standard generally stipulates the organized emission standards for pollution sources (chimneys), which are characterized by non-methane total hydrocarbons and total VOCs; the limits for the limits at the boundary of the plant are defined, and are characterized by non-methane total hydrocarbons and total VOCs; , Characterized by non-methane total hydrocarbons. In 2018, the state will issue emission standards for the printing industry. By then, the printing industry in the country will have a new, all-embracing emission standard. The successive introduction of standards can also be seen from the side, the emission of VOCs in the printing industry is indeed a problem.

In line with the implementation of the standard, Shanghai formulated the "Guidelines for the Control of Volatile Organic Compounds in the Printing Industry" in 2016. According to different printing processes, the guide proposes emission reductions for VOCs from sources, processes, management, and end-of-pipe management. Other provinces and cities have similar documents issued.

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