Catalytic Reduction of Nitric Oxide

As another example from chemical kinetics, we consider the catalytic reduction of nitric oxide (NO) by hydrogen which was studied using a flow reactor operated differentially at atmospheric pressure (Ayen and Peters, 1962). The following reaction was considered to be important 

Data were taken at 375,400 C, and 425 °C using nitrogen as the diluent. The reaction rate in gmol/(min g-catalyst) and the total NO conversion were measured at different partial pressures for H2 and NO. 

A Langmuir-Hinshelwood reaction rate model for the reaction between an adsorbed nitric oxide molecule and one adjacently adsorbed hydrogen molecule is described by  

For the isothermal regression of the data, using our standard notation [y=f(x,k)] we have, 

Parameter vector Independent variables Output vector Model Equation 

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From the results of other authors should be mentioned the observation of a similar effect, e.g. in the oxidation of olefins on nickel oxide (118), where the retardation of the reaction of 1-butene by cis-2-butene was greater than the effect of 1-butene on the reaction of m-2-butene the ratio of the adsorption coefficients Kcia h/Kwas 1.45. In a study on hydrogenation over C03O4 it was reported (109) that the reactivities of ethylene and propylene were nearly the same (1.17 in favor of propylene), when measured separately, whereas the ratio of adsorption coefficients was 8.4 in favor of ethylene. This led in the competitive arrangement to preferential hydrogenation of ethylene. A similar phenomenon occurs in the catalytic reduction of nitric oxide and sulfur dioxide by carbon monoxide (120a). 

Table 4.5 Experimental Data for the Catalytic Reduction of Nitric Oxide...

Richter, M., Trunschke, A., Bentrup, U., Brzezinka, K.W., Schreier, E., Schneider, M., Pohl, M.M., and Fricke, R. 2002. Selective catalytic reduction of nitric oxide by ammonia over egg-shell MnOx/NaY composite catalysts. J. Catal. 206 98-113. 

To illustrate this criterion, consider a simulation problem chosen to be similar to the catalytic reduction of nitric oxide (A3, K11) ... 

Amiridis, M.D., Duevel, R.V., Wachs, l.E. 1999. The effect of metal oxide additives on the activity of VjOj/TiOj catalysts for the selective catalytic reduction of nitric oxide by ammonia. Appl Catal B Environ 20 111-122. 

Burch, R. and Scire, S. Selective catalytic reduction of nitric oxide with ethane and methane on some metal exchanged ZSM-5 zeolites. Appl. Catal, B Environmental,... 

Long, R. Q. and Yang, R. T. Selective Catalytic reduction of nitric oxide with ethylene on copper ion-exchanged Al-MCM-41 catalyst, Ind. Eng. Chem. Res., 1999, Volume 38, Issue 3, 873-878. 

The reduction of nitric oxide by char in the presence of hydrogen or carbon monoxide was carried out over a temperature range of 500 -900°C. The reaction could be analyzed by assuming first order with respect to nitric oxide. The predominant mechanisms are the catalytic reduction of nitric oxide by hydrogen or carbon monoxide over char surface. The rate obtained under a = 4W7 was approximately equal to the rate of noncatalytic reduction of... 

Kinetic study of the selective catalytic reduction of nitric oxides with hydrocarbon in diesel exhausts... 

The kinetics of the selective catalytic reduction of nitric oxides (NOx) on a proprietary high temperature catalyst with diesel as the reductant have been studied. The objective was to derive a kinetic model that can be used for real time simulation of the catalyst. In the extension, the real time simulation will be used when controlling the injeetion of reductant. This is a requirement for achieving a high efficiency and a low fuel penalty. The response time and the NOx conversion level upon transient diesel injection was found to be dependent on the temperature. At temperatures below 570 K very low or no NOx conversion was observed. Above 570 K a small conversion was observed. No direct response upon diesel injection could be distinguished and the NOx conversion was independent on the hydrocarbon concentration. As the temperature was increased the response became apparent and then faster and the conversion level gradually became more dependent on the hydrocarbon concentration. Above 700 K the response was immediate (response time less than 15 s) and the conversion level was directly dependent on the hydrocarbon concentration. It was concluded that the NOx reduction proceeds via the formation of a hydrocarbon intermediate and the successive reaction between the hydrocarbon intermediate and NOx. When this reaction mechanism was modeled mtiny features of the catalyst behaviour were reproduced. 

A. Baiker, P. Dollenmeier, and M. Glinski, "Selective Catalytic Reduction of Nitric Oxide with Ammonia." 1. and II, Appl. Catal.. 1987,2S, 351-364 and 365-380. 

Sakamoto, E., T. Ohnishi and T. Arakawa, 1994, Catalytic reduction of nitric oxide with propane over Ln-Pt ion exchanged zeolites (Ln = rare earth), in Zeolites and Related Microporous Materials State of the Art 1994, eds J. Weitkamp, H.G. Karge, H. Pfeifer and W. Holderich, Vol. 84 of Studies in Surface Science and Catalysis (Elsevier, Amsterdam) pp. 1537-1540. 

The catalytic reduction of nitric oxide with ammonia was studied... 

Julie Doherty, MSc thesis, UCD, Selective Catalytic Reductions of Nitric Oxide with Ammonia and Urea over Copper and Iron-based catalysts, 2004. 

Huang Z, Zhu Z. Liu Z, Liu Q (2003) Formation and reaction of ammonium sulfate salts on V205/AC catalyst during selective catalytic reduction of nitric oxide by ammonia at low temperatures. Journal of Catalysis 214 213-219... 

Qi G, Wang Y, Yang R T (2008) Selective catalytic reduction of nitric oxide with ammonia over ZSM-5 based catalysts for diesel engine application. Catal. Lett. 121 111-117. 

Long R.Q, Yang R.T (1999) Catalytic performance of Fe-ZSM-5 catalysts for selective catalytic reduction of nitric oxide by ammonia. J. Catal. 188 332-339. 

Delahay G, Valade D, Guzman-Vargas A, Coq B (2005) Selective catalytic reduction of nitric oxide with ammonia on Fe-ZSM-5 catalysts prepared by different methods. Appl. 

Wu Z, Jiang B, Eiu Y (2008) Effect of transition metals addition on the catalysts of manganese/titania for low temperature selective catalytic reduction of nitric oxide with ammonia. Appl. Catal. B 79 347-355. 

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