Expermental Study Of The Flue Gas Composition On No-char Reaction Under High Temperature Condition

For a long period of time in the future, the coal will be the main body ofChina’s energy consumption, while the coal used for power plants is the mostimportant part of the coal consumption. Coal combustion is a major source of airpollutants NO_x. During the process of NO_xformation, the reaction of NO-charhave a significant impact on fina l NO_x emissions, so be able to correctly predict thetrue burning of various factors affecting the NO–char reaction environment is ofgreat significance to reduce NO_x emissions. The author built a high-temperaturedrop tube furnace （HDTF）, and did a detail study of the conditions of hightemperature flue gas composition on NO-char reaction.The char samples were produced in the simulated real combustion flue gaswith Simulated High-temperature Entrained Flow Reactor （SHEFR）. CHN elementanalyzer and TGA and mercury porosimetry were used to analyse the coal and thechar, and then used HDTF with the ratio of different kinds and concentrations of theflue gas composition to study the impact of only one kind of flue gas at differenttemperatures on the NO–char reaction which would provide a theoretical basis forthe better in the future to reduce NO emissions.Through the experimental study concluded that under the63ms retention timeconditions, SHEFR char samples obtained developed pore structure.In the hightemperature conditions, when background gas was only N2, NO-the reaction of charmainly affected by the diffusion effect, NO reduction rate increased with the rise oftemperature.When joined other gas components, CO could be significant positive tothe reaction, low concentration of CO will promote the formation of active surfacecarbon atoms, the sensitive temperature existed with the concentration of CO ris ingwhich made NO reduction rate rise up quickly. With the concentration of O₂risingNO reduction increased, then decreased, and the concentration of0.8%O₂madeNO reduction ratio to be maximum, if the concentration of O₂continue to increase,it will consume the activity of char surface atomic which cause NO reduction ratiodecreased. The influence of SO₂of the reaction is very small, the reduction of NOinfluence of the reaction need temperature continuous change or a long stay time, ina real pulverized coal burning process, the influence of SO₂is very small. Thechange of concentration of CO₂have small effect to the reaction, in other studies italways be treated as background gas.