Theoretical study on the effect of H_(2)O on the formation mechanism of NO_(x) precursors during indole pyrolysis

The incineration technology of kitchen waste is one of the effective technologies to achieve the resource utilization of municipal solid waste.Pyrolysis is an important stage of incineration.Indole is a rich initial product in the pyrolysis process of kitchen waste,and the presence of H_(2)O has a significant impact on the decomposition of indole to form NO_(x) precursors.Therefore,this study uses density functional theory method to study the effect of H_(2)O on the thermal decomposition of indole to produce NH_(3),HNCO,and HCN.When H_(2)O participates in the reaction,it can provide oxidative groups to generate a new product HNCO,which is different from the previous findings by indole pyrolysis without the presence of H_(2)O.Meanwhile,this study theoretically proves that NH_(3) is easier to form than HCN.This is consistent with the phenomenon that NH_(3) release is higher than HCN release in pyrolysis experiment.In addition,compared with the individual pyrolysis of indole,the participation of H_(2)O reduces the energy barriers for the formation of NH_(3) and HCN during indole pyrolysis,thereby promoting the formation of NH_(3) and HCN.

Detailed in-furnace measurements with reburning of superfine pulverized coal in high CO_(2)concentration

This paper presents detailed measurements of gaseous species during the reburning process with high CO_(2)concentration in a bench-scale furnace.Superfine pulverized coal,with the average particle size below or around 20μm,is used as the reburning fuel.The data of flue gas concentration(NOx,HCN,NH_(3),CH_(4),O_(2),CO,CO_(2)etc.)is obtained in order to reveal the intrinsic connection between NOx emissions and other influential gaseous species at different positions of the furnace.The finding concludes that the advantage of superfine pulverized coal with regard to NO reduction is more efficient in homogeneous stage rather than heterogeneous stage.Meanwhile,the evolution of HCN and CH_(4)agrees well with each stage of NO reduction,which indicates that these gaseous species are favorable for NO abatement.Eventually,oxygen consumption rate for superfine pulverized coal is relatively faster,conducive to strengthen both homogeneous and heterogeneous NO reduction under CO_(2)reburning condition.