Experimental Study On Characteristic Of Biomass Reburning Denitrification

NO_Xwhich was produced by large-scale coal-fired power plant boiler hasbecome one of the major air pollutants. Biomass reburning can effectively reduceNO_Xemissions in the atmosphere. Biomass is a renewable and high heat production.Biomass can achieve CO₂"zero emissions "and is in line with low-carbon economyresource. Compared with coal, biomass has high volatile but almost no sulfur andoften has very low ash content. So using biomass as fuel, do not worry about theformation of sulfur and ash pollution processing, making them become the mostattractive renewable energy resources.In this paper, the component concentration of biomass was determined bychemical method at first. And Pyris1TGA thermo balance analyzer was used toresearch the combustion characteristics of two kinds of biomass. And the relationshipbetween the biomass pyrolysis and reburning denitrification rate was analysed. Thestudy found that the biomass has lower nitrogen,sulfur content, higher volatile contentand easy to fire. So it is a better denitrification material.The experimental had set up the simulation reburning units. Using a commonNortheast hull and poplar as a reburning fuel, a power plant burning coal as the mainfuel to study the re-ignition characteristics of denitrification.The reburningdenitrification rates of woody plants are higher than those herbaceous plants, thesmaller the particle size of biomass, the more apparent denitrification effect is. Thedenitrification rate of biomass reburning achieved the best apparent at the rebumingtemperature was950-1050℃, and it can achieve the maximum rate of pyrolysis over1000℃. The yield of volatile herbs not significantly increased when the temperaturecontinues to increase. At this point, the denitrification rate of woody plants washigher than those in other conditions. Two kinds of biomass fuels could achieve theoptimum stoichiometric ratio in the experimental conditions. The particle size wasgreater impact on the rate of denitrification under the conditions that the reburning ratio range from10%to15%. The denitrification efficiency increasedwith increasing of the concentration of NO_Xand then decreased in the maincombustion zone. The reason is that the increasing concentration of NO_Xis conduciveto positive reaction. When the concentration of NO_Xincreased to certain extent, alarge number of NO_Xwere oxidated, the denitrification rate was declined.In this paper, improvement of reburning denitrification which participates in theadditives studied based on biomass advanced reburning denitrification. It was foundthat sodium and potassium can broaden optimum reaction temperature range. NaOH,Na₂CO₃, KOH, K₂CO₃could promote the reburning effect of approximately10%increase. Calcium acetate and calcium magnesium acetate have the dual effect ofdesulfurization and denitrification. Calcium magnesium acetates as a catalyst usingthe denitrification rate of90%. Using calcium magnesium acetate as a catalyst couldget denitration rate of90%. While adding Fe2O3to the reburning zone additives in thehigh temperature section, denitrification rate of advanced reburning increased about12%. Experiments show that fly ash is a good advanced reburning additive. Addingfly ash15%of fuel as an additive, denitrification rate increased about9%. Because ofthe low price of fly ash, it applies to actual production.