Experiment Research Of Low Temperature Characteristics Of Biomass Flue Gas And Drying Characteristics Of Biomass

As one of the most important utilized methods of renewable energy, biomass power generation has been supported and developed in many countries. Our country started to develop biomass power generation later than western countries. During the development of these years, some problems have emerged gradually. Biomass has a relatively high content of chlorine (C1) but a low content of sulphur (S), which causes a high content of HC1in flue gas after the combustion. The high content of HC1brings the problem of hydrochloric acid dew point and the deposit of condensed acid liquor, both of which have important impact on the design of exhaust gas temperature and anti-corrosion meassures of tail flue of biomass-fired power plants. Currently, the design experience of coal-fired power plants are often used for reference to design biomass-fired power plants, resulting in relatively high exhaust gas temperature for biomass-fired power plants. Rational use of exhaust waste heat will be benefical to energy-savinge, emission-reduction and economic benefits of power plants. Woody and straw herbaceous plants are the main fuel for the biomass-fired power plants of our country, whose moisture content is high and not stable. The current drying method for the biomass fuel is natural drying in most biomass-fired power plants, which restricts the advance of biomass energy utilization efficiency seriously. How to dry the biomass fuel with the exhaust waste heat of biomass-fired power plants will be good at reducing exhaust gas temperature of biomass-fired power plants and have important significance for the advance of biomass energy utilization efficiency. To solve the above problems, this article carried out some previous research and obtained some results as followed:On the basis of determination of the full straw chlorine content, the release characteristics of chloride from biomass straw combustion was researched. The results showed that biomass straw has a considerable content of chlorine and the chlorine content of wheat straw could reach to about1%in mass. The impact of vapor and chlorine on the hydrochloric acid dew point and the concentration of acid liquor was analyzed by the experiment research on the condensation of mixed gas containing HCl. In the process of straw combustion, the first influence fact of chloride release was combustion temperature, the second one was halting time and the last one was combustion atmosphere. The hydrochloric acid dew point was just a little higher than water dew point. Within the test range of the HCl concentration (0-1200ppmv), the largest difference was less than12℃. The condensed hydrochloric acid mass concentration was considerable, although the HCl concentration in the mixed gas was not very high.Thermogravimetric drying and hot wind experiment research on the drying characheristics of biomass was conducted. The results showed that the drying temperature should below160℃in case of the release of volatilization. The influence of drying temperature, initial moisture content, straw species and hot wind speed on the drying time was different. The optimun drying temperature of biomass straw under different initial moisture content was preliminarily determined. The commparison between the two results of thermogravimetric drying experiment and hot wind experiment was conducted.