Brown, AL
1998
Modeling Soot Derived from Pulverized Coal
Brown, A.L. and Fletcher, T.H.
Energy & Fuels, 12:745-57 (1998).
A semiempirical model has been developed for predicting coal-derived soot. The main feature of the model is a transport equation for soot mass fraction. Tar prediction options include either an empirical or a transport equation approach, which directly impacts the source term for soot formation. Also, the number of soot particles per unit mass of gas may be calculated using either a transport equation or an assumed average. Kinetics are based on Arrhenius rates taken from published measurements. Radiative properties are calculated as a function of averaged optical constants, predicted gas temperatures, predicted gas densities, and the soot mass fractions. This model has been incorporated into a comprehensive coal modeling code and evaluated based on comparisons with soot, temperature, and NOx measurements for three experimental cases. Accurate predictions of soot yields have been achieved for both laminar and turbulent coal flames. Larger scale turbulent predictions illustrated that inclusion of a soot model changed the local gas temperatures by as much as 300 K and the local NOx concentration by as much as 250 ppm. These predictions demonstrate the necessity for an accurate soot model in coal combustion systems.
1997
Soot in Coal Combustion Systems
Fletcher, T.H.; Ma, J.; Rigby, J.R.; Brown, A.L. and Webb, B.W.
Prog. Energy Combust. Sci., 23:283-301(1997). Funded by ACERC.
Soot is generated from coal when volatile matter, tar in particular, undergoes secondary reactions at high temperatures. A description of soot in coal flames allows better calculations of radiative transfer and temperatures in near-burner regions, which in turn allows more accurate predictions of NOx formation in coal-fired furnaces. Experiments are reviewed that examine the formation, agglomeration and properties of coal-derived soot, including pyrolysis experiments and combustion experiments. This review includes the types of experiments performed, the soot yields obtained, the size of the soot particles and agglomerates, the optical properties of soot, the relationship between coal-derived soot and soot form simple hydrocarbons, and attempts to model soot in coal flames.
Modeling Soot in Pulverized in Coal Flames
Brown, A.L.
Modeling Soot in Pulverized in Coal Flames, M.S./BYU, August 1997. Advisor: Fletcher
Brown, AL
1998
Modeling Soot Derived from Pulverized Coal
Brown, A.L. and Fletcher, T.H.
Energy & Fuels, 12:745-57 (1998).
A semiempirical model has been developed for predicting coal-derived soot. The main feature of the model is a transport equation for soot mass fraction. Tar prediction options include either an empirical or a transport equation approach, which directly impacts the source term for soot formation. Also, the number of soot particles per unit mass of gas may be calculated using either a transport equation or an assumed average. Kinetics are based on Arrhenius rates taken from published measurements. Radiative properties are calculated as a function of averaged optical constants, predicted gas temperatures, predicted gas densities, and the soot mass fractions. This model has been incorporated into a comprehensive coal modeling code and evaluated based on comparisons with soot, temperature, and NOx measurements for three experimental cases. Accurate predictions of soot yields have been achieved for both laminar and turbulent coal flames. Larger scale turbulent predictions illustrated that inclusion of a soot model changed the local gas temperatures by as much as 300 K and the local NOx concentration by as much as 250 ppm. These predictions demonstrate the necessity for an accurate soot model in coal combustion systems.
1997
Soot in Coal Combustion Systems
Fletcher, T.H.; Ma, J.; Rigby, J.R.; Brown, A.L. and Webb, B.W.
Prog. Energy Combust. Sci., 23:283-301(1997). Funded by ACERC.
Soot is generated from coal when volatile matter, tar in particular, undergoes secondary reactions at high temperatures. A description of soot in coal flames allows better calculations of radiative transfer and temperatures in near-burner regions, which in turn allows more accurate predictions of NOx formation in coal-fired furnaces. Experiments are reviewed that examine the formation, agglomeration and properties of coal-derived soot, including pyrolysis experiments and combustion experiments. This review includes the types of experiments performed, the soot yields obtained, the size of the soot particles and agglomerates, the optical properties of soot, the relationship between coal-derived soot and soot form simple hydrocarbons, and attempts to model soot in coal flames.
Modeling Soot in Pulverized in Coal Flames
Brown, A.L.
Modeling Soot in Pulverized in Coal Flames, M.S./BYU, August 1997. Advisor: Fletcher