Heterogeneous formation of nitrous oxide from char-bound nitrogen

Application of Density Functional Theory to the Study of the Reaction of NO with Char-Bound Nitrogen during Combustion

“…8,9 These nitrogen surface species can then be converted to N 2 , NO, and N 2 O in the second stage of combustion after reacting with O 2 . 4,10,11 Some studies have tried to relate the evolution of nitrogen oxides with nitrogen groups present in the char before the combustion process. However, no direct relation between the form of the nitrogen in the char and the evolution of nitrogen oxides has yet been found.…”

“…The evolution of N 2 O during the heterogeneous reaction was also consistent with the rates of production in the steady state and in the transient state conditions for the reaction NO + (-CNO) f N 2 O + C(O). 11 Further complications arise from the fact that nitrogen can be incorporated into the char structure from reactions of NO, resulting in an increase in the char-nitrogen content during oxidation. Such reactions are particularly important at temperatures of around 800-1000 K below the conventional temperatures of operation, 1200-1400 K, of fluidized beds.…”

Fuel-N Conversion to NO, N2O and N2 During Coal Combustion

“…Molina et al (2000) compared models of coal particle combustion and pathways of fuelnitrogen conversion into nitrogen oxides presented by Wendt and Schulze (1976), Shimizu et al (1992), Goel et al (1994), Visona and Stanmore (1996) and Soete et al (1999).…”

“…The models proposed by Visona and Stanmore (1996) as well as by de Soete et al (1999) are described above. A feature of the model presented by Wendt and Schulze (1976) is carbon oxidation to CO and char-nitrogen oxidation to NO in pores of heterogeneous particles.…”

Mechanism study on the influence of in situ SO removal on N2O emission in CFB boiler

“…However, the reported N 2 O emission level even reached 360 mg/m 3 at part load condition for a CFB boiler with thermal output above 200 MW [3], which is much higher than conventional pulverized coal-fired power plants. The nitrogen chemistry in CFB combustion and other fuel utilizing industry has long been a research focus [4][5][6][7][8][9] but it is still not fully understood because of the complex coupling of in-furnace combustion, heat and mass transfer, homogeneous and heterogeneous chemical reactions, etc. The dependence of N 2 O emission on important process parameters such as furnace temperature, excess air ratio, stoichiometry, with or without the presence of limestone was studied [3,[10][11][12][13], but the detailed mechanism still deserves more research effort.…”