Synergistic combustion of coal with natural gas

Using an improved coal-devolatilization model and a simple char-burnout model, we explore possible synergisms in the simultaneous combustion of coal and natural gas. After describing our own work briefly in the context of the conversion of oil boilers to coal burning, we consider the direct use of pulverized coal or of coal-water slurries with gas augmentation, and the two-stage use of pulverized coal or coal-water slurries with gas augmentation. In the first case, we identify advantageous interactions in cofiring which speeds up char-burnout. In the second case, the primary role of the first stage is the “methanogasification” of coal analogous to, and possibly more effective than, the hydrogasification of coal. In both cases, simultaneous coal-gas combustion appears to be synergistic.