INTRODUCTION: TUNGSTEN OXIDE (WO3) IS A WIDE BAND GAP SEMICONDUCTING METAL OXIDE [1]. IT EXHIBITS VARIOUS CHEMICAL PROPERTIES WHICH MAKE IT VERY PROMISING FOR APPLICATIONS IN ELECTROCHOROMIC DISPLAYING [2] PHOTOCATALYSIS [3] AND PARTICULARLY IN GAS SENSORS [4]. WO3 PLAYS A ROLE AS A SENSITIVE LAYER FOR DETECTING SMALL QUANTITIES OF NOX, NH3, O3, H2 AND SO ON [5]. DENSITY FUNCTIONAL THEORY (DFT) CALCULATIONS ARE USEFUL IN STUDYING THE STRUCTURAL AND ELECTRONIC PROPERTIES OF OXIDE SEMICONDUCTORS.RECENTLY, THERE HAVE BEEN NUMEROUS THEORETICAL STUDIES ON WO3, INCLUDING DFT AND HATREE-FOCK (HF) CALCULATIONS [6].

IN THIS STUDY, REDUCTION OF POLUTION OF COMBUSTION IN THERMAL CRACKING FURNACE IS INVESTIGATED BY REBURNING METHOD AND USE OF DIFFIUSION BURNER. IN THIS METHOD, WITH STAGE COMBUSTION PROCESS AND USE OF NON-STOICHIOMETRIC REACTION, PRODUCTION OF NOX WILL BE REDUCED. THE CASE STUDY AND BOUNDRY CONDITION IN THIS REASERCH IS FROM GENT UNIVERSITY EXPERIMENTAL FURNCE. THE FURNACE IS THREE DIMENTIONAL. FUEL AND AIR ENTER WITH 14 DIFFUSION BURNERS THAT LOCATED IN THE SIDE WALL OF BURNERS. ANALYSIS WAS PERFORMED ON DIFFERENT AIR FUEL RATIOS FOR DIFFERENT CLASSES OF BURNERS IN ORDER TO CREATE RICH AND LEAN CONDITION OF THE FUEL PLATES WITH CONSTANT HEAT CAPACITY. THE RESULTS OF SIMULATION, IS USED FOR OPTIMIZATION AND DETERMIN OF OPTIMAL VALUES FOR EQUILIBRIUM PROPORTIONS IN RICH AND LEAN CONDITION. MORE EVER THE RESULTS OF THIS STUDY SUGGEST THAT USE OF PROPER BALANCE RATIOS MAY REDUCE THE NOX PRODUCTION MORE THAN 16%.