Effect of Volatile−Char Interaction on the NO Emission from Coal Combustion

Abstract

To clarify the effects of volatile-char interaction on the redistribution of fuel-N to N2 during devolatilization and the reduction of NO through gas-solid reactions during combustion, two types of experiments were performed on a novel reactor. The separate combustion of volatile and char and the combustion of entrained pulverized coal, and the formation of NO was examined between 800 and 1100 degrees C by using four typical Chinese coals with different ranks. The effect of volatile-char interaction on fuel-N conversion to NO during combustion was elucidated through comparing the NO emissions from the two types of combustion experiments. The results show that the volatile-char interaction is more important in the redistribution of fuel-N to N2 during devolatilization than in the reduction of NO over 900 degrees C, and a contrary conclusion is obtained below 850 degrees C for all used coals. A specific parameter has been proposed to characterize the relative importance of the volatile-char interaction in the redistribution of fuel-N to N2 during devolatilization to the interaction in the reduction of NO to N2 during simulataneous combustion of volatile and char. The results are of significance for minimizing the NO formation in industrial combustion processes.

Kinetics investigation on the reduction of NO using straw char based on physicochemical characterization

“…Compared with the large amount of investigations on the reaction of NO and coal-char (Aarna and Suuberg, 1997;Johnsson, 1994;Li et al, 1998;Lu et al, 2009;Teng et al, 1992;Yamashita et al, 1993;Yao et al, 2008), researches on the interaction between NO and biomass char at high temperatures are limited. However, previous results have shown that there are still some obvious differences in the physicochemical characteristics and the reactivity of NO with biomass char and coal char (Dong et al, 2009b;Sahu et al, 2010;Vassilev et al, 2010;Wang et al, 2010a;Yin et al, 2009).…”

Combustion of hazardous biological waste derived from the fermentation of antibiotics using TG–FTIR and Py–GC/MS techniques

“…The initial peak for NO formation was observed at around 330°C, due to the primary degradation of volatile-N. The second peak was focused around 580°C, resulting from the combustion of char-N (Yao et al, 2008). In order to better understand the formation of N species, the total FTIR integral values for all N species were correlated with the total N content of the raw ARs material, as shown in Fig.…”

Drying sewage sludge using flue gas from power plants in China

“…The dried sludge has more ash and volatile content and lower calorific value than the coal, which is a disadvantage for the combustion purpose (Jayanti et al 2007;Yao et al 2008). To minimize the effect on CFB operation, 11.4 tons of sludge, equivalent to 5% of daily consumption of coal in CFB, was mixed with coal to incinerate.…”