ΜΕΛΕΤΗ ΗΛΕΚΤΡΟΚΑΤΑΛΥΤΙΚΩΝ ΚΑΙ ΚΑΤΑΛΥΤΙΚΩΝ ΑΝΤΙΔΡΑΣΕΩΝ ΣΕ ΚΕΛΛΙΑ ΚΑΥΣΗΣ ΚΑΙ ΑΝΤΙΔΡΑΣΤΗΡΕΣ ΤΡΙΩΝ ΦΑΣΕΩΝ

Abstract

THE OXIDATION OF NH3 TO NO WAS INVESTIGATED IN THE FUEL CELL NH3, NO, N2, PT OR PT-10%RHIIZRO2(8%Y2O3)IIPT OR PT-10%RH, AIR AT TEMPERATURES BETWEEN 950- 1300 K, AND ATMOSPERIC PRESSURE. THE NEW FUEL CELL DESIGN WITH THINER ELECTROLYTE AND MODIFIED ELECTRODE PREPERATION RESULTS SELECTIVITY UP TO 95% AND AN INCREASE TO POWER DENCITY AND FUEL CELL LIFE TIME BY 400, 3500% RESPECTIVELY. BASED ON PHYSICOCHEMICAL CONSEPTS, A MATHEMATICAL MODEL IS DEVELOPED TOPREDICT FUEL CELL CHARACTERISTICS. USING SIMILAR SOLID OXIDE CELLS, THE TECHNIQUE OF CYCLIC VOLTAMETRY HAS BEEN APPLIED FOR THE FIRST TIME IN CONJUCTION WITH MASS SPECTROMETRY AND ONLINE GAS CHROMATOGRAPHY TO INVESTIGATE THE CHEMISORPTIVE AND CATALYTIC PROPERTIES OF POROUS METAL CATALYST FILMS. THE CASE OF O2 ADSORPTION AND C2H4 OXIDATION ON PT WERE EXAMINED. IT WAS FOUND THAT CYCLIC VOLTAMETRY CAUSES A CYCLIC VARIATION IN CATALYST WORK FUNCTION ANDPROVIDES USEFUL IN SITU INFORMATIONS ABOUT COVERAGES OF ABSORBED SPECIES AND ABOUT THE OCCURANCE OF NEMCA EFFECT. FIXED BED CATALYTIC REACTOR IN WHICH GAW AND LIQUID PHASES FLOW CONCURENTLY DOWNWARD, TERMED AS TRICKLE BEDS, AREBECOMING WIDELY USED IN CHEMICAL PROCESSING, PARTICURALY IN PETROCHEMICAL INDUSTRY. A TWO DIMENSIONAL STEADY STATE MODEL IS DEVELOPED TO DESCRIBE THE REACTIONS BETWEEN ONE GASEOUS AND TWO NON-VOLATILE COMPONENTS IN AN ISOTHERMAL PARTIALLY WETTED CATALYTIC PELLET WITH UNIFORM OR NON-UNIFORM CATALYST MATERIAL. (TRUNCATED ABSTRACT)