Char Nitrogen Conversion to NO_xin a Fluidized Bed

Role of ash on the NO formation during char oxidation of biomass

“…Similar increasing NO release trends were seen for the straw and the torrefied wood. This trend has been observed during char combustion of biomasses previously [24][25][26][27], and may be attributed to that less and less of the initially formed NO is reduced as the char oxidation proceeds [21][22][23][24][25]. Interestingly this trend cannot be observed for the sunflower, DDGS or for any of the demineralized biomasses.…”

“…Nevertheless, understanding the NO release from a single particle is a prerequisite for reliable combustion simulations. Experimental studies show that the total conversion of char-N to NO decreases as the particle size increases [21][22][23][24][25]. Two explanations for this behavior have been suggested: (1) a larger particle has more char able to reduce the NO giving lower release of NO and (2) the ratio -diffusion rate of initially formed NO, from the char particle to the bulk gas phase, divided by the char consumption rate of N -decreases with increasing particle size [26,27].…”

N2O decomposition over the circulating ashes from coal-fired CFB boilers

“…The N 2 O formation mechanisms include the homogenous oxidation of hydrogen cyanide, heterogeneous oxidation of fixed nitrogen in char residue and reduction of NO with char or CO [24][25][26]. About 10-50% of the volatile cyan and cyanide compounds of the fuel nitrogen, such as HCN, are oxidized homogeneously to N 2 O.…”

“…It could be an important path of N 2 O formation from char-N, depending on fuel type and pyrolysis conditions [24][25][26].…”

Progress of circulating fluidized bed combustion technology in China: a review

“…NO x emission from CFB combustion are well studied in the literature [54,55]. Various factors, such as coal type, bed temperature, air staging, and limestone, can affect the NO x emission from CFB.…”