Experimentation Research for Deoxidize Reaction Process of NO_X Adopt Different Reburnning Fuels
|School||Harbin Institute of Technology|
|Course||Thermal Power Engineering|
|Keywords||reburning technology biomass NOBXB reduction effiency|
Entering the 21 century, people’s requirements towards the quality ofenvironment are getting stricter with the development of China’s economy andthe level’s improvement of people’s living. And the NOBXB releasing from powerplants are harmful to the environment. So it is necessary to take some effectivemeasures to reduce the concentration of NOBXB that releasing from power plants.And the technology of reburning as one of effective measures has been appliedextensively recently. However, there are very littlie studies about reburningtechnology in China. Hence, it is necessary to study variety of effective factorsduring the reburning of the fuels. At present, there are two ways to study thereburning which are numerical calculation and experimental study. As thelimitations of numerical calculation, it is more significative to take experimentalstudy ways.In order to get the key effective factors during the processes of NOBXBreduction, we have doing some research use one kinds of soft coal, straw and cornstalk as reburning fuels about the reduction ability that reduce the NOBXB on the onedimension drop tube furnace. And based the results of experiment to analysis theeffects of category of reburning fuels, granularity of reburning fuel, proportion ofreburning fuel, excessive coefficient of air, retain time and temperature ofreburning zone towards the efficiency of NOBX Breduction. The experiment resultsshow that at the same conditions different reburning fuels have different NOBXBreduction effiency as the discrepancy of physics structure and chemical structure.And for the given reburning fuel, the key effecitive factors toward the NOBXBreduction effiency are proportion of reburning fuel, excessive coefficient ofair,and retain time. Besides, the experiment results also show that at theconditions that temperature is no less than 1100 degree, when the excessivecoefficient between 0.7and0.8, proportion of reburning fuel between 10% to 25%,the NOBXB recuction efficiency can reach to at least 60% when the retain time is noless than 600ms and 80% when the retain time is no less than 800ms, and whenthe excessive coefficient chose 0.9, and proportion of reburning fuel between 15%to 25%, the NOBXB recuction efficiency can reach to at least 80% when the retain time is no less than 800ms for the corn stalk. For the straw, at the condition thattemperature is no less than 1100 degree, when the excessive coefficient between0.7and 0.8, the NOBXB recuction efficiency can reach to 60% to 75% when the retaintime no less than 600ms. For the soft coal used during the experiment processes,we can get only 40% NOBXB recuction efficiency at different conditions as it containhigher ash and lower volatiles. Compared the ability of NOBXB recuction efficiencyof soft coal, straw and corn stalk,we can easly conclude that use the biomass asreburning fuels can obtain well effect. Meanwhile, we can obtain the results thatthe most important factors that effecting the efficiency of NO reduction areexcessive of air, retain time, scale of reburning fuels during the process ofreburing for one fuel.By analysis the changes of concentration and reacting rate of methane,ethylene, hydrogen cyanide, ammonia, carbon monoxide and hydrogen comparedwith nitrogen oxides, we can conclude that most of nitrogen oxides are reducedby methane and ethylene, and the hydrogen have little action to the reduction ofnitrogen oxides. Besides, the carbon monoxide is maily acting as a catalystbetween the reaction of nitrogen oxides and char, so the carbon monoxide haslitte contribution to the homophase reaction with nitrogen oxides.