GB1102847A - Estimated tap temperature calculator for basic oxygen furnace - Google Patents

Abstract

1,102,847. Measuring temperature electrically. LEEDS & NORTHRUP CO. Nov. 18, 1966 [March 14, 1966], No. 51705/66. Heading G1N. The temperature that the melt in a basic oxygen furnace will attain at the moment of tapping is estimated continually during the refining process by determining electrically the actual temperature of the melt, adding to this a signal representative of the temperature rise associated with the oxidation of all the carbon in the melt and subtracting from this a signal representative of the temperature rise associated with the oxidation of the tap carbon content, i.e. the carbon remaining in the melt at the moment of tapping. For low carbon melts the temperature rise associated with the oxidation of all or the tap carbon is non-linearly related to the actual quantity of carbon due to the concurrent production of slag (FeO). For high carbon melts the relationship is approximately linear because little slag is produced. For high carbon melts, the above signals are obtained respectively from a melt temperature computer 10, Fig. 1, which may be of the type described in Specification 1, 087, 439, a carbon content computer 14, in which the carbon content is measured and whose output signal is representative of the corresponding temperature rise, and an adjustable linear potentiometer 18, the signals being combined in amplifier 22 and the estimated temperature indicated at 26. For low carbon melts in which an appreciable amount of heat is evolved in the production of slag, this is allowed for by determining the carbon removal efficiency of the furnace, obtained by measuring the rate of removal of carbon from the furnace in computer (36), Figs. 2, 3 (not shown), and dividing this in divider (44) by a signal representative of the rate of flow of oxygen into the furnace, measured by flowmeter (40). The resultant signal also representative of the required temperature rise associated with the carbon content is fed to amplifier 22. The actual carbon content, non- linearly related to the above temperature rise, may be indicated at 69, Fig. 3 (not shown), on a non-linear scale, or at (54), Fig. 2 (not shown), on a linear scale, function generator (48) introduced between the connection to the meter (54) and divider (44) linearizing the signal, and a second function generator (58), introduced before the amplifier 22, producing a signal proportional to the input to function generator (48). Similarly to account for the non-linear relationship between the tap carbon content and the corresponding temperature rise, a function generator (30), Fig. 2 (not shown), may be included between the potentiometer 18 and amplifier 22 or alternatively a non-linear potentiometer, Fig. 3 (not shown), may be used.