Combustion control of gas leaving steel converters - gas-air suction-unit kept at constant operating level increases steel output

摘要

Gas leaving the converter goes through a system contg. a gap for sucking in air, a heat-exchanger for burning the gas, a gas-cleaning plant, a suction unit, and an afterburner on the chimney-stack outlet. the gas is fed with air to give an excess air number alpha = 0.1-1, and the suction unit is kept at an operational level matching the amt. of combustion prods. when alpha = 1 and the max. rated capacity of the heat-exchanger is not exceeded. During initial melting, the amt. of gas is small and the air sucked in is adequate for complete combustion in the heat-exchanger. As the converter gas increases, the air sucked in is reduced and a point reached where it is inadequate for complete combustion so the residual gas is burned in the afterburner. During the transition between these two moles, an amt. of inert gas consisting of CO2 and N2 sweeps through the system, sepg. the two types of gas mixt. i.e. one contg. O2 the other contg. CO. At the end of melting, combustion is again completed in the heat-exchanger. The process is thus very safe with no danger of an explosion. Using this method, the intensity of the blast in the converter can be raised, thus increasing steel prodn. by 20-25%.