| Fluorine is an element of great environmental interest and fluoride is one of the pollution control species according to GB3095-1996. Combustion of coal is a potential source of fluoride in the atmosphere and environment. In this paper, a series of key problems on the distribution and occurrence characteristics of Chinese coals, the fluoride emission mechanism and conversion process during coal combustion, and fluorine retention technology during coal combustion were systemically analyzed and studied by the integration of the theoretical, experiment and industry application.The research work content is an important component part of the Basic Research Foundation of Nation (G1999022211), subsidized by Nation Natural Science Foundation of China (59876036) and Natural Science Foundation of Zhejiang|>rovince of Cbina(596097).In this paper, the research work consists Of four research aspects. First, the study on determination methods of fluorine in coal, fly ask, boiler bottom ash and flue gas. Second, the study on the distribution and occurrence characteristics of Chinese typical coals. Third, the study on the mechanism, behavior of fluoride during coal combustion. Fourth, the mechanism, experimental and industry application studies on fluorine retention technology during coal combustion.In the first research aspect, by comparing pyro-hydrolysis, oxygen bomb combustion and alkali-fusion methods, it has been shown that application of pyro-hydrolysis?fluoride ion-selective electrode (ISE) method is the most accurate, precise and successful method to the fluorine determination of coal, fly ash and bottom ash. The most important work in this aspect is that we have improved the monitoring standard method of fluorine concentration in flue gas, established the more accurate and successful monitoring procedures for fluorine concentration in flue gas of combustion coal boiler.In the second research aspect, the distribution and occurrence characteristics of Chinese coal have been systemically researched. The fluorine contents of 180 coal-samples from 18 different provinces are determined by pyro-hydrolysis-ISE method, the distribution regularities of Chinese coal have been obtained. The correlation between fluorine and ash, chlorine, sulphurs, phosphorus has been analyzed, the washibility of fluorine and its organic affinity are determined by means of the float-sink experiment. The occurrence modes of coal are researched in details by means of extracting experiment. The origin of fluorine in coals and their probable occurrence mode in coals have been discussed respectively.In the third research aspect, fluorine emission characteristics and mechanism during coal combustion have been studied systemically in tube furnaces for the first time. The influencing factors on the fluorine emission and the relationship of fluorine emission with combustion temperature, retention period, combustion atmosphere, coal type,particle size of coal, SiC*2 and CaO substance in coal have been obtained. The production mechanism and kinematics model of gaseous fluoride during coal combustion have been proved for the first time. The conversion process of fluoride during coal combustion in industrial and power plant boiler, the distribution of fluorine in combustion product of coal have been investigated.In the fourth research aspect, the mechanism, experimental and industry application studies on fluorine retention technology during coal combustion have been put into effect.(1) put forward fluorine retention technology during coal combustion, the efficiency of fluorine removal and influence factors have been systemically researched such as type of fluorine retention agent, combustion temperature, retention time, Ca/F molar ratio, particle size and microcosmic structure of fluorine retention agent.(2) Comparing the efficiency of fluorine removal of fluorine retention agent, developing fluorine retention agent to adapt to high temperature combustion.(3) CaO-HF reaction mechanism has been studied in the view...
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