Χρήση στερεών ηλεκτρολυτών για την βελτιστοποίηση της απόδοσης αντιδράσεων βιομηχανικού ενδιαφέροντος

Abstract

The present PhD thesis entitled "Use of Solid Electrolyte Membrane Reactors for the enhancement of Industrially Important Chemical Reactions" focuses on the examination of very important chemical reactions. These reactions are involved both in the environmental protection technology and specifically in the reduction of nitrogen oxides emissions and also in environmental friendly power production, through the perspective of "hydrogen economy". The ingenuity of the present study deals with the use of innovative Solid Electrolyte Membrane Reactors (SEMR) and also with the application of the electrochemical promotion technique, in order to increase their catalytic activity as well as their selectivity towards the desirable products. More specifically, this study is divided in two parts. The first part is dealing with the selective catalytic reduction/decomposition of nitrogen oxides (2), 22)), emitted from power plants, by the simultaneous destruction of unburned hydrocarbons, which are also present in the flue gases. The second part involves the study of chemical reactions taking place during hydrogen and "green" electrical energy production. The selective catalytic reduction/decomposition of NOX, was studied in both oxideion and proton SEMRs. It was found that the application of the electrochemical promotion technique resulted to a rate increase of the studied reactions and this phenomenon was purely Faradaic. The reduction of nitrogen oxides by hydrogen, produced by a steam electrolysis cell (constructed with a high-temperature type proton conductor), was really innovative. In the following, methane dry reforming reaction and the Reverse Water Gas Shift (RWGS) reaction were both studied in oxygen anion SEMRs. These two chemical reactions are involved in hydrogen production, while if they are going to be carried out internally in a Solid Oxide Fuel Cell (SOFC), it is possible to produce simultaneously electrical energy. It was found that the application of the electrochemical promotion technique increased the rate of the RWGS reaction by a non-Faradaic way, while in the case of methane dry reforming limited catalyst's deactivation, by enhancing the oxidation of the deposited carbon. Finally, during SOFC operation, promising results were achieved, in terms of electrical energy production.