Atomization of Coal-Water Slurry Using a Pulse Combustor

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with realistic efficiencies (not isentropic), the elimination of the boost compressor could give a more significant improvement in overall system performance. The result of this calculation, with an air/liquid mass ratio of 0.5:1 (reported for CWS atomization in gas turbine applications [5]), represents the minimum expected improvement due to elimination of the boost compressor. The improvement from 47.8 to 48.2 percent efficiency represents a nearly 1 % increase in output at fixed input. In a system with an air/liquid ratio of 1:1 the efficiency would improve from 47.4% to 48.2%. Similar calculations could be carried out for conventional power plants adapted to operate on CYSt Airblast atomization of slurry generally results in droplets which consist of several coal particles [6]. This results in significantly longer burning times for the agglomerated particles than those for the original particles in the CWS. Pulse atomization provides the potential for reproducing the particle size distribution of the slurry in the spray, making better use of the work done in grinding the original coal. In initial studies of pulse atomization [7] using a reed-valved pulse combustor (Fig. 3) approximately 3.5 g/s of slurry was atomized essentially to the original grind of the coal in the slurry. While the reed-valved combustor provided a rapid test, repeated reed failures prevented extended testing. To improve reliability the pulse combustor described below was constructed. 2. EXPERIMENTAL Two basic types of tests were performed. The first was pulse atomization of the slurry and combustion of the slurry in the pulse atomization/combustion test rig shown in Fig. 4. The second was high