Method of protecting the refractory walls of industrial furnaces against radiation

摘要

993,010. Preventing corrosion; protecting furnace walls from radiation. INSTITUT DE RECHERCHES DE LA SIDERURGIE FRANCAISE. Oct. 10, 1961 [Oct. 18, 1960], No. 36285/61. Heading F4B. The refractory walls or roof of a furnace in which combustion gases circulate near and parallel to the walls or roof in the opposite direction to the main flame are protected against radiation by injecting a hydrocarbon fuel with a low velocity into the stream of recirculating gases so that the hydrocarbon is cracked to form a cloud of carbon particles screening the walls or roof. In an open hearth furnace heated by a main flame 8, with recirculating combustion gas currents f, fuel oil is supplied by water cooled injectors 9a spaced three quarters of the furnace length from the end having an operative burner 5a to form a sheet 13 of carbon particles screening the roof 2 from radiation from the flame 8 and the melt 7. The injectors may be arranged to form a conical spray, or to form a flat sheet of fuel. The hydrocarbon injected to form the carbon cloud may be fuel oil, tar or a gas having a high carbon/hydrogen ratio such as propane, and may be taken from the main furnace fuel supply, or may be supplied separately. Alternative injectors 9b are used when the furnace is reversed and burner 5b is operative.