Development of a pulverized coal burner.

The pulverized coal combustion burner which is suitable for the high temperature scrap pre-heating has been developed to reduce the electric power consumption of electric arc furnace.This burner needs only a small amount of pure oxygen (under 10% of the theoretical oxygen for the combusion of PC) to improve the flame stability, and the large portion of required oxygen is supplied by air to minimize the scrap oxidation and to reduce the oxygen cost.The characteristics of this burner are as follows.(1) High thermal efficiency;Approximately 45% of the thermal efficiency was achieved when the average scrap temperature reached to 900°C.(2) Minimized scrap oxidation;Only 20kg/ton of scrap was oxidized at the average scrap temperature 900°C.(3) No problem for air pollution;The NOx in the exhaust gas is easily reduced to N2 in the furnace by the following reaction.NO+CO→1/2N2+CO2And more than 90% of SOx in the exhaust gas is converted to CaSO4 by the CaO in the furnace.In addition, the large PC input rate burner (PC 32kg/min) was successfully developed and the scale-up technology was established.