The combustion behavior of blends of two low-grade anthracite byproducts with two bituminous coals was determined in a bench-scale test apparatus that was designed to simulate the combustion conditions (bed density, bed height, air flow rate, and particle residence time) on a travelling-grate stoker. Axial temperature profiles in the bed at various locations, pressure drops across the bed, and flue gas compositions were monitored at regular time intervals during the experimental runs. Residual ash was analyzed for carbon burnout and clinkering potential. The study revealed that the particle size distribution of the coals influenced the bed conditions during combustion and ultimately the carbon burnout. Blending anthracite byproducts, of appropriate size distribution, with bituminous coals decreased the pressure drop across the bed during combustion and reduced the clinkering potential by reducing the caking properties of the blend and improving the air distribution through the bed. Tempering the fuel bed (with water) had a greater effect on combustion performance than the particle size distribution of the feed coals, since tempering was found to alter the size distribution by agglomerating the fines. Tempering lowered the bed density, produced rapid and uniform travel of the ignition plane, and increased the carbon burnout. Several correlations between the condition of the fuel bed during combustion and the carbon conversion efficiency were obtained.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology