Application of the submerged nozzles for rotary furnace firing: modelling studies.

The potential advantages were investigated of employing nozzles for furnace firing, based on computational fluid dynamics modelling. Simulations were conducted of the heat transfer in a rotary anode furnace used to refine blister copper from a direct-to-blister flash furnace, and in a converter type rotary furnace used to reduce converter slags from Cu-Pb-Fe alloy treatment. The heat exchange in the anode furnace was considered to be a steady state process, and in the converter was assumed to be a transient process due to the ongoing reduction process. The results were applied to a rotary anode furnace fired with a burner and two nozzles supplying natural gas fuel and to a converter equipped with different numbers of nozzles. The application of submerged nozzles together with the gas burner in the anode furnace resulted in a reduction in fuel consumption. A higher average bath temperature of 1 219 degrees C was achieved for a system equipped with a burner supplying 100 Nm3/h of fuel and two nozzles each supplying 50 Nm3/h, compared with 1 076 degrees C when fired only with a burner supplying 200 Nm3/h of fuel. The use of the nozzles also improved the uniformity of the temperature field in the bath. The standard deviation for the average bath temperature was 18.2 degrees C compared with 26.3 degrees using only a burner. For the same volume of fuel consumed, the heat utilisation efficiency was higher when larger amounts of gas were delivered through the nozzles. The average bath temperature was 1 219 degrees C when 100 Nm3/h of gas was delivered through the burner and 50 Nm3/h through each nozzle compared with 1 205 degrees C for a system supplying 150 Nm3/h through the burner and 25 Nm3/h through each nozzle. For the converter slag reduction process, the highest average slag temperature of 1 227 degrees C was obtained using a furnace equipped with 4 nozzles with a standard deviation of 4.99, compared with 1 212 degrees C and a standard deviation of 6.36 using 3 nozzl
The potential advantages were investigated of employing nozzles for furnace firing, based on computational fluid dynamics modelling. Simulations were conducted of the heat transfer in a rotary anode furnace used to refine blister copper from a direct-to-blister flash furnace, and in a converter type rotary furnace used to reduce converter slags from Cu-Pb-Fe alloy treatment. The heat exchange in the anode furnace was considered to be a steady state process, and in the converter was assumed to be a transient process due to the ongoing reduction process. The results were applied to a rotary anode furnace fired with a burner and two nozzles supplying natural gas fuel and to a converter equipped with different numbers of nozzles. The application of submerged nozzles together with the gas burner in the anode furnace resulted in a reduction in fuel consumption. A higher average bath temperature of 1 219 degrees C was achieved for a system equipped with a burner supplying 100 Nm3/h of fuel and two nozzles each supplying 50 Nm3/h, compared with 1 076 degrees C when fired only with a burner supplying 200 Nm3/h of fuel. The use of the nozzles also improved the uniformity of the temperature field in the bath. The standard deviation for the average bath temperature was 18.2 degrees C compared with 26.3 degrees using only a burner. For the same volume of fuel consumed, the heat utilisation efficiency was higher when larger amounts of gas were delivered through the nozzles. The average bath temperature was 1 219 degrees C when 100 Nm3/h of gas was delivered through the burner and 50 Nm3/h through each nozzle compared with 1 205 degrees C for a system supplying 150 Nm3/h through the burner and 25 Nm3/h through each nozzle. For the converter slag reduction process, the highest average slag temperature of 1 227 degrees C was obtained using a furnace equipped with 4 nozzles with a standard deviation of 4.99, compared with 1 212 degrees C and a standard deviation of 6.36 using 3 nozzl