Selective Catalytic Reduction of NOx in the Presence of Oxygen

Potassium-Containing Coal Chars as Catalysts for NOx Reduction in the Presence of Oxygen

“…A number of potential NO x sorbents have been and are being investigated, including metal oxides, , ion-exchanged zeolites, − FeOOH and Fe 2 O 3 dispersed activated carbon fibers (ACF), − pitch-based ACF, active coke, and activated carbons. − ,− In the absence of O 2 , the kinetics and capacities of activated carbons for NO adsorption from the gas phase were low 61-63 but they increased dramatically with increasing O 2 concentration. − ,, Rubel and co-workers 44-48 found that, in the presence of gaseous O 2 , the NO was converted to NO 2 at the carbon surface and was condensed within the micropores, and consequently, a high NO x adsorption capacity is achieved. The studies of Kaneko and co-workers 54-58 showed that ACF doped with FeOOH and Fe 2 O 3 had a notable NO adsorption capacity even in the absence of O 2 .…”

Effect of Pressure on NOx Adsorption by Activated Carbons

“…One requirement for an efficient adsorption−desorption process is a material that has a high, reversible adsorption capacity. A number of potential sorbents have been examined, including metal oxides, , ion-exchanged zeolites, − FeOOOH and Fe 2 O 3 dispersed on and in activated carbon fibers, − and pitch-based activated carbon fibers . While activated carbons have been investigated as possible NO x reduction catalysts, − studies indicated that they exhibited low NO adsorption capacities and slow NO adsorption rates. , However, recent work has shown that NO x capacities and adsorption kinetics are very good for commercially available activated carbons when exposing them to simulated combustion gas mixtures containing O 2 , CO 2 , SO 2 , and H 2 O at temperatures between 293 and 393 K. − During adsorption, the carbon catalytically converted NO in the combustion gas to NO 2 , which was then adsorbed, and subsequently desorbed during temperature-induced desorption. − At atmospheric pressure and 343 K, the NO adsorption capacities were determined to be as high as 150 mg of NO 2 /g of carbon if, and only if, O 2 was present in the reactant mixture.…”

In-containing BEA zeolite for selective catalytic reduction of NOx

“…In this last case, one of the central problems is the loss of activity by fouling due to the production of oxygen in the decomposition. From the discovery of Iwamoto et al [1], demonstrating that the Cu-ZSM-5 zeolite presents a great activity for the direct decomposition of NO, was generated a great enthusiasm in the international community of catalysis [2][3][4]. But, when verifying it, even in the most propitious conditions, the activity is too low for its commercial use; the interest by this system has been decreasing.…”