Studies on the reduction of nitric oxide by carbon: the nitric oxide-carbon gasification reaction

Synthetic coal chars for the elucidation of NO heterogeneous reduction mechanisms

“…Other authors have observed a change in the activation energy between 600 and 750°C [8,24,25], reported also in previous works by our research group [26,27]. This change in activation energy could be related to a change in the reduction mechanism.…”

“…However, other authors [8] have proposed the formation of a dimer, (NO) 2 , as a previous step to NO dissociative chemisorption. Then, the previous sequence of reactions would be:…”

“…Moreover a deeper knowledge of the chemistry involved in the formation and the reduction of NO X is required. Many authors have performed NO heterogeneous reduction studies on carbonaceous materials using, mainly, chars from phenol-formaldehyde resins [4][5][6][7][8][9], graphites [10] and activated carbons [11][12][13]. The use of model compounds, with controlled heteroatom content and well defined functionalities, is a useful approach that has been used by other authors [14,15] to study the release of nitrogen compounds from char combustion.…”

Heterogeneous reduction of nitric oxide on synthetic coal chars

“…The C-NO reaction did not start until 600ºC, CO 2 and N 2 being the main reduction products. Under the experimental conditions used in this work in the TPR tests neither CO nor N 2 O, as described by other authors [14,15], were detected. The evolutions of N 2 and CO 2 are shown in Figure 2.…”

Advanced combustor design concept to control NOx and air toxics

“…Many researchers have published data relating to NO reduction on char and have computed kinetic rates for the reduction reaction (Chan et al, 1983;Levy et al, 1981;Song et al, 1981a;de Soete, 1990;Furusawa et al, 1980;Teng et al, 1992;Suuberg et al, 1990;Rodriguez-Mirasol et al, 1994). All of these researchers conducted their experiments in the absence of O 2 ; they fed mixtures of Ar/NO or He/NO over a bed of char and computed kinetic rates for the reduction reaction based on measurements of gas concentrations in the effluent.…”