Research On The Transformation Properties Of Fuel-N Under The Oxy-coal Conditions

Compared with the conventional combustion, circulating flue gas leading the presenceof high concentration of CO₂in the oxy-fuel combustion, this bring big change to thepulverized coal coal combustion process, and big change also happen to the nitrogen.Further understanding of these processes will help us know more about the low NOxemission during the O₂/CO₂combustion.First, in this article we use the vertical tube furnace study the conversion characteristicsof the gaseous volatile N components NH3, HCN under the atmosphere of high CO₂concention, discuss the atmosphere, temperature, coal rank and other factors on the releaseof NH3and HCN process of law. Compared with the Ar atmosphere, in CO₂atmosphere thevolatile N released in the form of HCN. As the temperature increases, the conversion rate toHCN increased significantiy in CO₂atmosphere. As the coal rank increases, theconversion rate to HCN showed decreasing trends in CO₂atmosphere.Further, we use furnace tube reactor study the combustation process of the pyrolysisproducts in CO₂atmosphere, study the analysis of atmosphere、temperature、coal rank andother factors on the conversion of volatile characteristics of N. We also usethe gas kinetics software CHEMKIN to study the coefficient of the peroxide、temperature,、CO₂concentration and other factors on the NO precursor conversion characteristics. In theCO₂atmosphere, as the temperature increase the conversion rate of NO increase largely, asthe coal rank increae the conversion rate of NO show a decrease trend, compared withthe Ar atmosphere, the conversion of NO rate was significantly higher in CO₂atmosphere.In the CO₂atmosphere, when the peroxide coefficient less than1.2it is not conduciveto inhibit NO precursor to NO, the higher the temperature the less conducive to inhibitNO precursor to NO, in fuel-rich conditions low CO₂concentration is conducive toinhibite NO precursor to NO, in Slightly lean-burn conditions high CO₂concentration isconducive to inhibit the NO precursor to NO.At last, in this paper we study the combustion experiments aboutanother coal pyrolysisproducts char at high concentrations of CO₂atmosphere, investigate the influences of temperature, O₂concentration, reaction atmosphere and other factors onthe conversion of char-N to NO. As the temperature increases, in CO₂atmosphere NOconversion first increases and then decreases, and the maximum appears at900℃,compared with the Ar atmosphere, O₂concentration is clearly larger affect the NOconversion in CO₂atmosphere, and the conversion rate of NO from the char-N is smallerthan the former.