Sarofim, AF
2000
Measurement of Soot and Char in Pulverized Coal Fly Ash
Veranth, J.M.; Fletcher, T.H.; Pershing, D.W. and Sarofim, A.F.
Fuel, 79(9), 1067-1075 (2000).
Contact: Veranth
Fast Cook-Off Tests of an HMX-based Propellant in Pool Fires
Eddings, E.G.; Sarofim, A.F.; Ciro, W. and Beckstead, M.W.
19th JANNAF Propulsion Systems Hazards Meeting, CPIA No. 690, Vol I, 2000, pp. 317.
Contact: Beckstead
1999
Char Nitrogen Conversion: Implications to Emissions from Coal-Fired Utility Boilers
Molina, A.; Sarofim, A.F.; Eddings, E.G. and Pershing, D.W.
Progress in Energy and Combustion Science, to be submitted, November 1999.
The contribution of the nitrogen present in the char on the production of nitrogen oxides during char combustion was analyzed. A literature review summarized the current understanding of the mechanisms that account for the formation of NO and N2O from the nitrogen present in the char. The review focused on 1) The functionalities in which nitrogen is present in the coal and how they evolve during coal devolatilization; 2) The mechanism of nitrogen release from the char to the homogeneous phase and its further oxidation to NO; and 3) The reduction of NO on the surface of the char. The critical analysis of these three issues allowed to identify uncertainties and well-founded conclusions observed in the literature for this system.
The existent models for the production of nitrogen oxides from char-N were also reviewed. A critic analysis of the assumptions made in these models and how they affect the final predictions is presented. Finally, a simplified version of these models was used to perform a parametric analysis of the incidence of the rate of NO reduction on the char surface, the rate of carbon oxidation, and the instant during the char oxidation when the nitrogen is released; on the total conversion of char-N to NO. The results underscore the importance of the reaction of NO reduction on the char surface on the final conversion of char-N to NO.
Measurement of Soot and Char in Pulverized Coal Fly Ash
Veranth, J.M.; Fletcher, T.H.; Pershing, D.W. and Sarofim, A.F.
Fuel, In Review, 1999.
The unburned carbon in the fly ash produced by low-NOx pulverized coal combustion has been shown by electron microscopy to be a mixture of porous coal char particles and aggregates of submicron particles, which are thought to be soot. The carbon is bimodally distributed with large soot aggregates mixed with the char in the particles larger than 10 microns and dispersed soot found with the submicron particles. A method for determining the mass of soot and char by liquid-suspension gravity separation was used with both laboratory-scale and power plant fly ash samples. For low-NOx, staged, pilot-scale combustion of bituminous coal the soot in the soot in the furnace exit ash was estimated to be 0.2 to 0.6% of the fuel carbon, which was about 35% of the total unburned carbon.
Sarofim, AF
2000
Measurement of Soot and Char in Pulverized Coal Fly Ash
Veranth, J.M.; Fletcher, T.H.; Pershing, D.W. and Sarofim, A.F.
Fuel, 79(9), 1067-1075 (2000).
Contact: Veranth
Fast Cook-Off Tests of an HMX-based Propellant in Pool Fires
Eddings, E.G.; Sarofim, A.F.; Ciro, W. and Beckstead, M.W.
19th JANNAF Propulsion Systems Hazards Meeting, CPIA No. 690, Vol I, 2000, pp. 317.
Contact: Beckstead
1999
Char Nitrogen Conversion: Implications to Emissions from Coal-Fired Utility Boilers
Molina, A.; Sarofim, A.F.; Eddings, E.G. and Pershing, D.W.
Progress in Energy and Combustion Science, to be submitted, November 1999.
The contribution of the nitrogen present in the char on the production of nitrogen oxides during char combustion was analyzed. A literature review summarized the current understanding of the mechanisms that account for the formation of NO and N2O from the nitrogen present in the char. The review focused on 1) The functionalities in which nitrogen is present in the coal and how they evolve during coal devolatilization; 2) The mechanism of nitrogen release from the char to the homogeneous phase and its further oxidation to NO; and 3) The reduction of NO on the surface of the char. The critical analysis of these three issues allowed to identify uncertainties and well-founded conclusions observed in the literature for this system.
The existent models for the production of nitrogen oxides from char-N were also reviewed. A critic analysis of the assumptions made in these models and how they affect the final predictions is presented. Finally, a simplified version of these models was used to perform a parametric analysis of the incidence of the rate of NO reduction on the char surface, the rate of carbon oxidation, and the instant during the char oxidation when the nitrogen is released; on the total conversion of char-N to NO. The results underscore the importance of the reaction of NO reduction on the char surface on the final conversion of char-N to NO.
Measurement of Soot and Char in Pulverized Coal Fly Ash
Veranth, J.M.; Fletcher, T.H.; Pershing, D.W. and Sarofim, A.F.
Fuel, In Review, 1999.
The unburned carbon in the fly ash produced by low-NOx pulverized coal combustion has been shown by electron microscopy to be a mixture of porous coal char particles and aggregates of submicron particles, which are thought to be soot. The carbon is bimodally distributed with large soot aggregates mixed with the char in the particles larger than 10 microns and dispersed soot found with the submicron particles. A method for determining the mass of soot and char by liquid-suspension gravity separation was used with both laboratory-scale and power plant fly ash samples. For low-NOx, staged, pilot-scale combustion of bituminous coal the soot in the soot in the furnace exit ash was estimated to be 0.2 to 0.6% of the fuel carbon, which was about 35% of the total unburned carbon.