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Show thermocouple was used. The efficiency of the pyrometer was better than 95% with a 15-second response time. Slag and Ash Deposition Probe To study the coal ash slagging and deposition tendencies on boiler convective tubes, a probe was developed based on the Canadian Combustion Research Laboratory design^7). A drawing of the Slag and Ash Deposition Probe (SADP) is shown in Figure 9. The SADP consists of a cooling gas distribution box and convective tubes. A compressed air/steam mixture was used for cooling media. Cooling gases enter the SADP gas distribution box and then the convective tubes. The convective tubes are five 50-mm (2-in.) Schedule 40 steel pipes, 300 mm (12 in.) long placed horizontally in a triangular pitch arrangement with 200 mm (4 in.) between the centers of the pipe. The other end of the pipe is supported by a metal plate, and the cooling gas exits the tubes into the atmosphere. Two "K" type thermocouples monitored the surface temperature of the tubes. The interior sides of the distribution box and the metal plate were insulated with ceramic board. Fuel The coal was a high volatile (HVA) bituminous from the Pittsburgh No. 8 seam (Westland No. 2 mine). The coal was washed and analyzed at the Consolidation Coal Company's Champion Preparation Plant before shipping and by IGT after the milling process (Appendix A) and particle size analyses of the ground coal were performed by the Particle Data Laboratory for each test trial. The particle analyses are summarized in the Rosin and Rammler chart in Figure 10 showing standard pulverized coal along with the three grinds used in the trials. The three coal particle sizes had an arithmetic volume (mass) mean of 40.62, 18.08, and 6.61 ym denoted by the numbers 30-300, 35-150, and 80-150. A coal particle size distribution not shown on the chart is a bimodal distribution numbered 80-50. A limited amount of test data were collected on coal grind 80-50. Microscopic shadow graphs were taken by Particle Data Laboratories of the finest (80-150) and coarsest (30-300) coal grinds. The results are shown in Figures 11 and 12 with scales of 100 and 200 urn. The 16 |