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Show are partially converted to N2 in the fuel rich stage. Many of the elementary chemical reactions (and sequence of reactions) responsible for NO~ destruction by staged combustion play sUbstantial roles ln determining the level of NOx produced by classical boiler flames. SCOPE OF THIS RESEARCH This work seeks to provide some additional insight into the conversion of fuel nitrogen by considering the totality of the processes in a liquid fuel combustor under fuel rich conditions. In addition to NO measurements, HCN and NH3 will be determined in the combustion environment. The following questions as they pertain to the conversion reactions of fuel nitrogen in the first stage of a staged combustor will be addressed: 1 What is the level of conversion of fuel nitrogen in the first stage? 2 What chemical kinetic processes affect the concentrations of nitrogenous species, especially in the post-flame gases? 3 Can the reactions affecting the first-stage nitrogen concentrations be manipulated to minimize NO formation in the second stage? These questions will be addressed through experiments conducted on a premixed tubular downflow combustor, using liquid fuels. The combustor has been designed to satisfy the following requirements: 1 Minimum temperature loss, to maximize control over experimental conditions. 2 In situ sampling of the combustion gases along the combustor axis to provide a time/temperature history of the chemical and physical processes. 3 Measurement of the major combustion species to characterize the combustion gases (02' CO, CO 2). 4 Measurement of major nitrogenous species (HeN, NH3 , NO) to more fully explain the nitrogen reactions and provide methods for further development of kinetic expressions which govern the concentrations. EXPERIMENTAL FACILITIES A complete description of the experimental facilities used in this presentation is available elsewhere in (1) and only a brief summary will be presented below. Furnace system and burner The investigations were carried out in a 30 cm diameter by 3.2 m long, vertical refractory-lined reactor which consisted of eight separate sections and was fired at a rate of 100 kwt (approximately 6 kg/h oil). The details of the experimental furnace are given in (1 and 2). The gas-phase residence times of 1-2 seconds were achieved with velocities of about 1.9 m/sec. The burner detail is described in (1) and consists of an oil gun and two separate air supply ducts for flame stabilization. 2 |
