Development of a Slit Burner

In iron and steel making processes, rapid, uniform heating of continuously mov i ng objects is often an important requirement. Igniting cokes in the firing furnace for sintering and heating strips are examples of processes where this requirement must be met. The conventional method in these processes involved the arrangement of numerous cylindrical, coaxial-type burners widthwise of the object to be heated. By this method, however, it was difficult to obtain a uniform width-wise temperature and therefore difficult to achieve fast heating. To solve the above-mentioned problems encountered with cylindrical burners, the authors developed a new gas burner on a scale suitable for practical utilization. The new burner features a slender rectangular slit, which serves as the gas and alr nozzle. The burner has three parallel rectangular ducts partitioned by walls. Fuel gas flows through the center duct, and air flows through the ducts on its two sides. The gas and air are mixed in the nozzle at the end of the ducts, and then forced out into the furnace. Few studies had previously been made on burners having such a rectangular nozzles, and there was no precedent for a practical-purpose rectangular-nozzled burner of industrial scale. Under the circumstances, the authors produced a model burner of practical utilization scale, performed flowability and combustion tests, and studied burner shapes for the planned use. Based on the results of these studies, a burner for a sintering firing furnace was manufactured and installed in an actual furnace. As a result, rapid , uniform heating was achieved, and fuel consumption was reduced to half that with conventional burners.