Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

KINETICS OF THE BIOFUELS-ASSISTED SCR OF NO x OVERAg/ALUMINA-COATED MICROCHANNELSOP-V-12J.R. Hernández, K. Arve, A. Kurman, K. Eränen, J. Wärnå, D.Yu. Murzin, T. SalmiLaboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre,Åbo Akademi University, Biskopsgatan 8, FI-20500, Turku/Åbo, Finland.Fax: +35822154479. E-mail: johernan@abo.fiIntroductionThe growing concern for the environment and the strict legislations regarding the mobilesources emissions have led to an emerging research in the area of environmental catalysis.Biofuels are regarded as an alternative solution for reducing the oil dependence in thetransport sector. The European Union (EU) has set the use of biofuels to be of 5.75% of thetotal vehicle fuel consumption in the EU by 2010. The goal for 2020 is set to 10%. Theexhaust treatment of conventional fuels has been studied in detail in a large amount ofindustrial and academic publications [1]. However, it is essential to understand the NO Xreduction as biodiesel is used. On the other hand, microreactors have emerged as analternative to conventional reactors: enormous improvements in energy efficiency, fasterreactions, improved yield, safety, reliability and better process control are achieved [2]. Wepresent here a systematic kinetic study for the selective catalytic reduction of NO X withbiodiesel. It is based on the rigorous treatment of the chemical transformations occurring inselective catalytic reduction of NO X in microchannels.Microreactor SystemThe gas-phase microreactor was designed at Åbo Akademi and the parts were purchasedfrom the Institut für Mikrotechnik Mainz GmbH (IMM). The device consists of a two-piececubic chamber with two inlets and one outlet, each with a tube diameter of 710 μm. The lowerpart of the chamber has two recesses, each filled with a stack of ten micro-structured platelets,which are connected by a diffusion tunnel. The first stack contains a total of ten mixingplatelets with nine semicircular channels of different radii but with a common center. Theyare arranged in the stack so that they meet the two inlets in alternation. The second stackconsists of ten rectangular platelets with nine parallel shallow microchannels (Ø = 460 μmand depth = 75 μm) coated with an Ag/Al 2 O 3 catalyst (see Fig. 1). A maximum gas flow of 50mL/min is permitted. Pressures and temperatures up to 50 bar and 600 ºC, respectively, can beachieved, making it possible to carry out a wide range of chemical transformations in gasphase.The kinetic experiments were carried out in the microreactor and the concentrations ofthe species were determined by GC and MS [3].189