NOVEL PROCESS OF NO REMOVAL FROM COMBUSTION FLUE GAS BY A REACTION WITH SULFUR DIOXIDE AND OXYGEN

AIR POLLUTION CONTROL TECHNOLOGIES FOR NOX REDUCTION ARE LIMITED BY THE RELATIVELY INERT NATURE OF NO. THIS DIFFICULTY CAN BE OVERCOME BY OXIDATION OF NO TO MUCH MORE REACTIVE NO2. SINCE FLUE GAS DESULFURIZATION SYSTEMS ARE REQUIRED FOR SO2 REMOVAL AFTER COMBUSTION OF SULFUR-CONTAINING FUELS, AND IT HAS BEEN PROVEN THAT NO2 CAN BE REMOVED EFFICIENTLY IN SLIGHTLY MODIFIED CALCIUM-BASED SO2 SCRUBBERS, THE CONVERSION OF NO INTO NO2 BECOMES A PROMISING STRATEGY FOR COMBINED NOX AND SOX REMOVAL. THIS PROJECT DEVELOPS A NOVEL CONCEPT: GAS PHASE NO TO NO2 CONVERSION BY MEANS OF A CHAIN REACTION WITH SO2 AND OXYGEN. THIS REACTION PROCEEDS UNDER SPECIFIC CONDITIONS IN THE PRESENCE OF AN EXTREMELY LOW AMOUNT OF ACTIVE SPECIES. IT IS NOT NECESSARY TO INJECT SO2 AND O2 IN FLUE GAS BECAUSE THEY ARE ALREADY PRESENT IN COMBUSTION GASES PRODUCED BY COAL BURNING. THIS NOVEL CONCEPT OFFERS THE ADVANTAGE OF LOW POLLUTION AFTER COMBUSTION OF HIGH SULFUR COALS BECAUSE A HIGHER SO2 CONCENTRATION IN FLUE GAS IMPROVES THE NO TO NO2 CONVERSION. THE EFFORT PROVIDES A LABORATORY-SCALE FEASIBILITY DEMONSTRATION OF THE NO TO NO2 CONVERSION IN THE GAS PHASE WITHIN REACTION TIMES, TEMPERATURES, AND OTHER CONDITIONS WHICH ARE IN THE PRACTICAL RANGE FOR APPLICATION IN BOILERS AND FURNACES.