From the Summary: 'To meet ever-increasing energy demands in the United States, greater utilization of our coal resources is required. However, coal combustion produces oxides of nitrogen (NOx) which present a health hazard. The main source of these emissions is the nitrogen that is chemically bound in the coal (1/2-2% by weight). This study represents a preliminary effort to elucidate the mechanism of fuel nitrogen conversion to NOx during coal oxidation. A literature review and physical model are presented. They indicate that the major influences on fuel NOx formation are oxygen concentration, fuel nitrogen content and combustion conditions (i.e. heating rate, temperature, pressure and residence time). A pulvedrized coal transport reactor to study low temperature coal oxidation has been constructed and successfully operated. Preliminary results indicate that considerable amounts of NOx may be formed at temperatures as low as 700oC. At low temperatures (700-1100oC) fuel NOx formation is highly temperature dependent and exhibits a rapid increase near a critical temperature., Above this temperature, excess air conditions promote conversion efficiency.'