| As the biggest coastal city in North China, Tianjin City has strong industrial base, and the high technology is developing rapidly, in addition, it owns the developed industry, complete industrial categories and industrial chain. Air pollutant emissions largely with it, which caused a lot of air pollution problems, and haze weather as the representative of atmospheric compound pollution events occur frequently. Volatile organic compounds(VOCs) were important precursors of atmospheric compound pollution, and therefore chemical composition and characteristics of VOCs emission source perform vital function on understanding the formation of regional air pollution and controlling regional air pollution.This paper established VOCs emission inventory of Tianjin industrial sources by estimating the emissions of 4 source categories and 27 industries which emission VOCs. In 2013, the total number of industrial VOCs emissions was 204,000 tons in Tianjin. As the major VOCs emissions industry in Tianjin, the number of VOCs emissions from the crude oil processing and petroleum products industry(the petrochemical industry) was 68,000 tons, and it was about one-third of the number of total industrial VOCs emissions. So it was selected as the object of this thesis.The emissions from sulfur recovery unit, heating furnace of PX unit and sewage plant and the ambient air in the factory were selected as the emission sources from the petrochemical industry by surveying investigation in the production process and the sewage process. Meanwhile, the applicable scope, precision and operating process of three common sampling methods were evaluated synthetically, and sampling and analysis method were suitable for this study were used to measure the sources.The chemical composition and species based on CB05 chemical mechanism of VOCs emission sources from were established based on the result of the sources measurement. Meanwhile, the characteristics of the petrochemical industry VOCs emission sources were studied, and results indicated that:(1) The emission concentration of stationary sources was 30-85 mg/m3 in the petrochemical industry with the rate of emission was 0.4-8 kg/h, and the concentration of ambient air was about 1.5 mg/m3. Aromatic hydrocarbons and halogenated hydrocarbons were the primary pollutant categories among the 8 VOCs categories,including: aromatic hydrocarbons, halogenated hydrocarbons, alkanes, ketones, alcohols, aldehydes, esters and phenols.(2) There were 19 kinds of volatile organic compounds quantitatively detected, and chloroform, p-xylene(m-xylene), undecane, benzene, formaldehyde, 1,4-dichlorobenzene, cyclohexanone, o-xylene as the particular pollutants of the petrochemical industry,which own high frequency and concentration.(3) The pollution distribution characteristics of four kinds of emission sources indicate that, the emission characteristics of stationary sources were closely related to production and sewage process. The particular pollutants from burning process include: chloroform, dichloromethane, benzene, toluene, etc. The major pollutants from sewage plant were less volatile than pollutants from ambient air.(4) Study on of photochemical reactivity characteristics of VOCs from the petrochemical activity indicate that, the major photochemical pollutants include: aromatic hydrocarbons, alkanes, halogenated hydrocarbons, phenols and ketones, and aromatic hydrocarbon was primary photochemical pollutant category. Benzene and toluene own highest photochemical reactivity contribution rates among aromatic hydrocarbons,so the emission of them should be controlled further. |
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