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Show INTRODUCTION This paper will present the results obtained during a demonstration project at Canadian Steel Foundry (CSf) in Montreal, where a conventional car bottom gas furnace was retrofitted with a pulse firing system. CSF is involved in melting and casting of metals followed by appropriate heat treament of the parts.The main objective of the demonstration project is to measure energy savings resulting from the following modifications brought to the heat treating furnace: - reconstruction of the furnace using ceramic fiber insulation. - reduction of the number of chimneys (from 10 to 2) and use of automatic flue dampers. - installation of a pulse firing system. The other objectives were to assess the product quality and productivity increase.We will first describe the characteristics of high temperature processes and how pulse firing systems are adapted to this application. Then we will present results and after the modifications. break down the energy fibers,automatic dampers and results will be discussed. HIGH TEMPERATURE PROCESSES of tests made on the furnace before These measurements will allow us to savings according to ceramic pulse firing. Finally the economic In direct fired fuel furnaces heat transfer is by radiation and convection. In natural gas furnaces radiation to the parts comes essentially from the furnace walls which are heated by the products of combustion. The net radiation between furnace walls and parts is a function of their temperature difference (T4furnace-T4p~rts ), so that as the parts are increasing in temperature tfi1S form of heat transfer is reduced. On the other hand heat transfer by convection can be increased by maximizing turbulence in the furnace at all temperatures. This can be achieved through the use of high velocity jet burners that deliver products of combustion at a high kinetic energy. Some might be concerned by the effect of high velocity gases at high temperatures on the load or the refractories. In fact these jets are rapidly diluted as shown on figure 1. In a free environment the characteristics of a high velocity jet are as follows: - the angle at the origin is approximately 22 0 - away from a transition zone (approximately 6 times the exit diameter) where the jet maintains its initial properties, the speed of the air decreases inversely proportionally to the distance from the face of the burners; so does the concentration of the fluid injected. - the jet entrains a mass rate proportional to the distance to the burner face From this fact,it follows that temperatures are decreasing very rapidly in the jet:examples are given for ambient air at 20oc,6000 c and 12000 c.We note that the mass rate entrained by the |