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Show NITROGENOUS EMISSIONS: THE ROLE OF SULPHUR AND EQUIVALENCE RATIO Anthony R. Burgess Department of Chemical Engineering University College London Torrington Place London W C 1 E 7 JE England Luis-Javier Molero Hamworthy Combustion Engineering Ltd Fleets Corner Poole, Dorset BH17 OLA England Abstract Nitrogen and sulphur are fuel constituents which contribute significantly to atmospheric pollution and to the deterioration of combustion equipment through the formation of A/Ox and SOx. Large concentrations of fuel-N and -S are normally present in liquid fuels of industrial interest, such as heavy or residual fuel oils. The extent which these species interact during or after their formation can be of relevance and depend on a number of factors, such as the concentrations of nitrogen and sulphur in fuel and the equivalence ratio. In the work presented a number of heavy gas oils and an oil-water emulsion were investigated. Baseline emissions of NOx (NO plus N02) and SO2, as well as other combustion products, were measured at three equivalence ratios, namely fuel-lean (<p = 0.833), stoichiometric (<p = 1.00) and fuel-rich (<p = 1.20). The effect of sulphur on nitrogenous emissions was assessed by the addition of increasing amounts of SO2 (gaS) to the combustion system. This caused the concentrations of NO and N02 to vary in different ways according to the overall equivalence ratio of the combustion system. Sizeable increases or decreases of the emissions of nitrogenous compounds were thus observed, which were attributed to the action of sulphur compounds on NOx-forming reactions or direct reaction between SO2 and nitrogenous compounds. Introduction In the last thirty years only a small number of investigations have focused on the effect of sulphur on the reactions of nitrogenous species originating from fuel nitrogen. Sulphur can have different effects depending on the process of formation and emission 1 |
