Testing and prediction of performance and emissions from bituminous (Drummond Colombia) and sub-bituminous (Adaro Indonesia) coals and their blends

We predict the combustion behavior and pollutant emissions of blends of a Colombian bituminous coal, Drummond, and an Indonesian sub-bituminous coal, Adaro, in pulverized-coal utility boilers. This work is based on full-scale numerical simulations with GLACIER, a powerful computational-fluid-dynamic (CFD) code that uses the two-mixture fraction approach which models two separate coal streams in the combustion chamber. By burning the coals and their blends in a pilot-scale test furnace, previously unknown information on the coal combustion, such as devolatilization and char oxidation kinetic parameters, was determined and the CFD model validated for the test furnace. The same set of parameters was used for the CFD model configured for an opposed-wall and a tangential fired utility boiler. Our results show good fits between numerical results and experimental data for gas temperature, CO₂, O₂, and NO_X, both in the test furnace and in the utility boilers, for single coals and their blends. We believe that the tool we developed can help utility companies make rational decisions on the use of new coals or coal blends so as to lower pollutant emissions while maintaining the same combustion efficiency.