METHOD AND DEVICE FOR BURNING NATURAL GAS IN OXYGEN IN ARCH STEEL-SMELTING FURNACE Russian patent published in 1999 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: method includes supplying natural gas and oxygen into cylindrical gas-oxygen mixing chamber of burner installed in furnace roof, side walls, or in working door gate; controlling consumption of natural gas and oxygen; periodically loading charge into furnace; heating and melting charge; determining content of carbon monoxide in effluent gases and measuring smelt temperature. Oxygen is fed into mixing chamber in the form of swirling stream, whereas natural gas is fed in transversal direction to oxygen stream. Jet of natural gas is displaced along longitudinal axis of chamber after loading of each portion of metal charge to value equal to 1.2-1.8 inner diameter of cylindrical part of chamber. Swirling fan-shaped burning torch with aperture angle 40 to 140 deg. is formed. Natural gas jets are disposed in lower part of chamber during first 5-45 min after loading of each portion of charge, after which gas jets are displaced into upper part of chamber and kept in this position until next portion of charge is started being loaded. 5-45 min after last portion is loaded, gas jets are displaced into upper part of chamber and kept in this position until charge is completely immersed under molten-pool level, after which jets are descended into lower part of chamber to be kept there until specified temperature of molten metal is attained. Ratio of natural gas and oxygen consumptions varies over the range of 0.1-0.39 when content of carbon monoxide in effluent gas is higher than 5% and from 0.4 to 0.5 at carbon monoxide content below 0.499%. Device consists of gas-oxygen burner installed in roof, side walls, and working door gate and, in turn, consisting of water- cooled cylindrical mixing chamber connected with oxygen-, natural gas-, and water-supply pipelines. Chamber is made in the form of cup with bottom on one end and diffuser (aperture angle 40-140 deg.) on the other. Upper part of chamber receives swirler and in internal cavity of cup there is cylindrical water-cooled core mounted in spaced relation to cup (gap equal to 0.2-0.7 outside core diameter) having internal axial canal and side holes communicating with axial canal. Core is provided with axial displacement means. EFFECT: increased volume of burning torch and burning temperature leading to increased productivity of furnace. 6 cl, 2 dwg, 1 tbl, 5 ex