OCR Text |
Show Changes in the mixture temperature or the coal-content in the fuel only had minor effects on the combustion results. It could not be determined how much of the fuel was absorbed by raw material in the kiln in unburned conditions and re-burned upon contact with the 1200°C hot mass. However, in the finished product no carbon content was found. Inspection of the burner nozzle itself showed neither deposits of combustion residues nor erosion. In addition, no clogging of the fuel line or nozzle developed. The trouble-free and ease of operation over an extended period of time in C OM combustion using the ultrasonic burner described here has proven the technical feasibility of applying this combustion system to a full scale plant. Economy The savings in operating costs is equal to the decrease in fuel costs, which was determined by the price difference between equivalent amounts of heavy oil and coal. The investment for the overall conversion to C O M firing in the rotary kiln was approximately $300,000. In comparison, the complete conversion of a 100% pulverized coal combustion system would have cost over $1 million, approximately 3-1/2 times the amount for C O M. During these test months, fuel savings of almost $80,000 were realized. In a pulverized coal system, the equivalent savings would have only been twice as much. Even with this simple calculation, the conversion from oil to C O M firing as described above shows clearly its economical merits. SUMMARY AND OUTLOOK From its technical and economical advantages presented above, the DUMAG ultrasonic burner is well suited for the combustion of coal-oil mixture and other viscous residue waste. The successful conversion to burn C O M on a rotary kiln at Kaii-Chemie shows that is is also economically feasible. This report covers more than one year's experience of this project in the manufacturing, transportation and combustion of 60/40 coal-oil mixture. 16-11 |