To increase the secondary combustion rate and heating efficiency of a melting furnace, etc., without shortening the service lives of refractories, etc., and suppressing the flying out of slag, etc., by using a gas containing an oxygen gas more than a specific amount as a combustion supporting gas for secondary combustion.
The method for improving secondary combustion rate and heating efficiency of melting furnace, etc., uses a gas containing ≥60% oxygen gas as a combustion supporting gas for secondary combustion. In order to heat the oxygen gas for secondary combustion to a high temperature, oxygen gas preheaters 5 are installed to the oxygen gas introducing sections of lances 2. Because of the preheaters 5, the oxygen gas can be heated to a temperature of about 1,100°C and the temperature of the oxygen gas at the discharge ports of the lances 2 can be maintained at ≥950°C. In addition, the flow speeds of the oxygen gas discharged from nozzles are set at 100, 250, and 500 m/sec. Therefore, when the melting of a raw material is accelerated or the temperature in a melting furnace, such as the converter, electric furnace, etc., is raised at the time of melting the raw material in the furnace, the raw material can be melted by reducing the used amount of fuel or the combustion supporting gas without worsening the operability of the furnace nor damaging refractories by improving the heating efficiency of secondary compustion.
KAWABATA RYO
TAKAOKA TOSHIO
ISHII TOSHIO
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