Allan, SE
1993
Ash Deposit Initiation in a Simulated Fouling Regime
McCollor, D.P.; Zygarlicke, C.J.; Allan, S.E. and Benson, S.A.
Energy & Fuels, 7 (6):761-767, 1993. (Also presented at the Seventh Annual Technical conference of the Advanced Combustion Engineering Center, Park City, UT, March 1993. Funded by US Department of Energy and ACERC.
Bench-scale pulverized coal combustion studies were performed to examine selected major factors that influence deposit initiation. Five coals of varying ranked and composition, including a Beulah-Zap lignite, a Dietz subbituminous coal, a Utah Blind Canyon western bituminous coal, and Illinois No. 6 and Pittsburgh No. 8 eastern bituminous coals, were fired in a laminar flow drop-tube furnace under simulated fouling conditions. Initially deposited particles as well as bulk fly ash were examined using scanning electron microscopy techniques. Deposited particle diameters ranged from 10 to 40 µm. Initial adhering particles were primarily iron-, iron-calcium-and iron-silica-aluminum-rich particles for the Pittsburgh No. 8, Illinois No. 6, Utah Blind Canyon, and Beulah coals. Utah Blind Canyon and Beulah deposits also included some calcium-silica-alumina-rich particles. Dietz deposits contained iron-and iron-calcium-rich particles, along with substantial barium- and barium-sulfate-rich species. These enriched particle species appeared common to all of the initial deposits, with their abundance being determined by the concentration in the original coals. The great majority of the initially deposited particles clustered in similar groupings above a certain "critical" mass and below a "critical" viscosity regardless of individual compositions. This indicates that the initial deposit particles are those with sufficient kinetic energy to impact the substrate inertially and with sufficiently low viscosity to adhere upon impaction. The propensity for initial ash deposition can be roughly related to the fraction of particles in the bulk fly ash possessing these mass and viscosity requirements.
Allan, SE
1993
Ash Deposit Initiation in a Simulated Fouling Regime
McCollor, D.P.; Zygarlicke, C.J.; Allan, S.E. and Benson, S.A.
Energy & Fuels, 7 (6):761-767, 1993. (Also presented at the Seventh Annual Technical conference of the Advanced Combustion Engineering Center, Park City, UT, March 1993. Funded by US Department of Energy and ACERC.
Bench-scale pulverized coal combustion studies were performed to examine selected major factors that influence deposit initiation. Five coals of varying ranked and composition, including a Beulah-Zap lignite, a Dietz subbituminous coal, a Utah Blind Canyon western bituminous coal, and Illinois No. 6 and Pittsburgh No. 8 eastern bituminous coals, were fired in a laminar flow drop-tube furnace under simulated fouling conditions. Initially deposited particles as well as bulk fly ash were examined using scanning electron microscopy techniques. Deposited particle diameters ranged from 10 to 40 µm. Initial adhering particles were primarily iron-, iron-calcium-and iron-silica-aluminum-rich particles for the Pittsburgh No. 8, Illinois No. 6, Utah Blind Canyon, and Beulah coals. Utah Blind Canyon and Beulah deposits also included some calcium-silica-alumina-rich particles. Dietz deposits contained iron-and iron-calcium-rich particles, along with substantial barium- and barium-sulfate-rich species. These enriched particle species appeared common to all of the initial deposits, with their abundance being determined by the concentration in the original coals. The great majority of the initially deposited particles clustered in similar groupings above a certain "critical" mass and below a "critical" viscosity regardless of individual compositions. This indicates that the initial deposit particles are those with sufficient kinetic energy to impact the substrate inertially and with sufficiently low viscosity to adhere upon impaction. The propensity for initial ash deposition can be roughly related to the fraction of particles in the bulk fly ash possessing these mass and viscosity requirements.