| OCR Text |
Show Considering these two effects, it was concluded that boiler rating would be reduced by 10 to 15 percent when burning COM. In summary, as a result of these analyses, we determined that the standard COM would not be completely burned in the furnace tube; that conditions conducive to deposition of molten and dry deposits may occur; that heat transfer characteristics in the boiler will be adversely affected, and that derating the boiler by 10 to 15 percent may be required. Further, because of the abrasive nature of coal, excessive wear of some metal parts could be expected. Experimental Results Results of tests conducted at Adelphi University (2) showed a build up of molten slag in the furnace tube and the entrance to the second pass. Deposits of fly ash in the flue tubes was also observed periodically. Sootblowers were recommended to blow the fly ash through the boiler. Maximum boiler operation was 24 hours. The COM was a 44% oil, 44% coal & 12% water mixture with coal particles sized so that 80% passed through 200 mesh. Water was used as an emulsifier (2). COM stability was satisfactory using a tank agitator and some tank heating. Heat tracing of the fuel supply lines was required and a special flow control valve was also found to be necessary. Results of the work conducted by Savage (6) at Ohio University also reported a build up of molten slag. COM was a 50-50 mixture with coal particles sized so that 70 percent passed through 200 mesh. Allied Oil Company provided the COM; Cleaver-Brooks provided technical assistance on the boiler. A primary objective of this program was the evaluation of the performance of existing boiler equipment over a relatively long period of operation. The boiler was fired with this COM at a turn down ratio of 6/1 and at maximum rated 15-6 |
