Richards, DO
1992
The Sensitivity of Entrained-Flow Coal Gasification Diffusion Burners to Changes in Geometry
Sowa, W.A.; Hedman, P.O.; Smoot, L.D. and Richards, D.O.
Fuel, 71(5):593-604, 1992. Funded by US Department of Energy, Morgantown Energy Technology Center.
Three axisymmetric diffusion flame burners were designed and installed on a laboratory-scale, downfired, entrained-flow, coal gasifier operated at pressures up to 560 kPa. Each burner was studied by varying reactor pressure, oxygen/coal ratio and steam/coal ratio. The gasifier performance was assessed by collecting space-resolved gas and char samples in the reaction chamber and analyzing them for carbon conversion, gas composition (CO, CO2, H2, H20 and CH4) and cold gas efficiency. Burner geometry affected carbon conversion, gas composition and cold gas efficiency. Each burner had unique flame structural characteristics that resulted in burner-unique trends with reactor pressure, oxygen/coal ratio and steam/coal ratio. At 560 kPa, diffusion flame burner performance approached premixed flame performance. The results from this study suggest that it might be possible to design a diffusion burner that outperforms a fuel-oxidant premixing burner for some operating conditions due to its flame structure and its characteristic energy transfer to the chamber. Performance characteristics of diffusion burners correlated with system pressure, oxygen/coal ratio or steam/coal ratio cannot be generalized into trends representative of all diffusion flame burners.
1986
Statistical Distributions of Coal Particle Sizes in Pulverized-Coal Combustion and Gasification
McDonald, J.B.; Richards, D.O.; Smith, P.J. and Sowa, W.A.
Annual Meeting of the American Statistical Assoc., 1986. 18 pgs. Not externally funded.
Coal particle size distributions for a Utah bituminous coal and a Wyoming subbituminous coal were modeled using four different probability density functions (GB1, GB2, lognormal, and lognormal by method of moments) and two engineering approximations. The pdf models of the particle size distributions were discretized and compared to the engineering approximations by simulating a coal combustion case and a coal gasification case using the comprehensive combustion model, PCGC-2. The gasification case used the Utah coal and the combustion case used the Wyoming coal. Significant differences were noticed between predictions using engineering approximations of the particle size distribution and predictions using discretized pdf approximations of the particle size distribution. The different methods of describing the particle size distribution affected most notably the simulators prediction of NOx.
Richards, DO
1992
The Sensitivity of Entrained-Flow Coal Gasification Diffusion Burners to Changes in Geometry
Sowa, W.A.; Hedman, P.O.; Smoot, L.D. and Richards, D.O.
Fuel, 71(5):593-604, 1992. Funded by US Department of Energy, Morgantown Energy Technology Center.
Three axisymmetric diffusion flame burners were designed and installed on a laboratory-scale, downfired, entrained-flow, coal gasifier operated at pressures up to 560 kPa. Each burner was studied by varying reactor pressure, oxygen/coal ratio and steam/coal ratio. The gasifier performance was assessed by collecting space-resolved gas and char samples in the reaction chamber and analyzing them for carbon conversion, gas composition (CO, CO2, H2, H20 and CH4) and cold gas efficiency. Burner geometry affected carbon conversion, gas composition and cold gas efficiency. Each burner had unique flame structural characteristics that resulted in burner-unique trends with reactor pressure, oxygen/coal ratio and steam/coal ratio. At 560 kPa, diffusion flame burner performance approached premixed flame performance. The results from this study suggest that it might be possible to design a diffusion burner that outperforms a fuel-oxidant premixing burner for some operating conditions due to its flame structure and its characteristic energy transfer to the chamber. Performance characteristics of diffusion burners correlated with system pressure, oxygen/coal ratio or steam/coal ratio cannot be generalized into trends representative of all diffusion flame burners.
1986
Statistical Distributions of Coal Particle Sizes in Pulverized-Coal Combustion and Gasification
McDonald, J.B.; Richards, D.O.; Smith, P.J. and Sowa, W.A.
Annual Meeting of the American Statistical Assoc., 1986. 18 pgs. Not externally funded.
Coal particle size distributions for a Utah bituminous coal and a Wyoming subbituminous coal were modeled using four different probability density functions (GB1, GB2, lognormal, and lognormal by method of moments) and two engineering approximations. The pdf models of the particle size distributions were discretized and compared to the engineering approximations by simulating a coal combustion case and a coal gasification case using the comprehensive combustion model, PCGC-2. The gasification case used the Utah coal and the combustion case used the Wyoming coal. Significant differences were noticed between predictions using engineering approximations of the particle size distribution and predictions using discretized pdf approximations of the particle size distribution. The different methods of describing the particle size distribution affected most notably the simulators prediction of NOx.