Study On The Emission Characteristic Of Polycyclic Aromatic Hydrocarbons From Coal Combustion

Due to its much greater abundance compared with other kinds of fossil energy and its more important position in the energy construction in worldwide, especially in China, the production and utilization of coal resource will take an important role in the development of social economy. However, it's easy to bring about second contaminants from the period of coal combustion such as SOj, NOx and so on, among which one is PAHs (polycyclic aromatic hydrocarbons). So it's very necessary to do some research on the formation, emission, and control of PAHs during the process of coal combustion, because trace PAHs is widely distributed, is generally difficult to decompose, is harmful with biological accumulation and three-cause tardy effects including carcinogenesis, aberration, mutation, and at the same time possibly synthesizes Dioxin (another kind of organic contaminant with stronger carcinogenesis) as an usher reagent.The research on 17 PAHs pollution during the process of coal combustion was divided into five stages, and research carried out in this paper was mainly focused on three stages of five. In order to analyze PAHs emitted from raw coals and coal burning correctly, effectively, conveniently, a complete analysis method, involving sampling, pretreatment, and detection, was established, according to commonly used foreign methods and regulations related to PAHs research. Based on this method, 31 national raw coals were collected and done with industrial, element analysis, data of PAHs content was obtained, and PAHs distribution law was discussed. Furthermore, some experiments concerning PAHs from the coal combustion were done in the minitype simulation furnace, creation mechanism of corresponding PAHs was researched, and seven factors, coal type, combustion mode, temperature, atmosphere, residence time, excessive air coefficient, Ca/S mole rate, etc. to possibly influence PAHs emission were analyzed in this article.At the same time, hearth residue, fly ash from air pre-heater, gas in the middle of economizer, gas before dust catcher, gas after dust catcher, and water in the dust catcher pool, were gathered during the PAHs experiments in a FBC at a certain power plant in Hangzhou. Data of PAHs content in those samples mentioned above were obtained and adopted to analyze the change of PAHs content in different samples of different condition.The relation of PAHs emission and Dioxin emission was discussed from theory and experimentation in this article, and it was indicated that PAHs could possibly synthesize Dioxin as an usher reagent.In order to be convenient for the mechanism research of PAHs formation, emission, and control during the process of coal combustion in next stage, systemic discussion was taken on development situation and trend at abroad and home. In addition, some tentative plans were proposed for the research of next stage.