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Dead banking of a mixer usually lasts from 12 to 14 days. Drying and heating of the mixer lining are performed with coke-oven gas with a forced air feed.The mixer is equipped with automatic recorders of the flow rates of gas and air. The feed of gas and oxidant is regulated by hand so as to ensure that the temperature of the working surface of the lining rises according to a given schedule.During heating of the lining we must endeavor to attain its uniform expansion, because otherwise there is the possibility of warping of the lining and falling-out of the brickwork. A collector which ensures uniform distribution of the jet in the working space of the mixer, without permitting local superheatings of the lining, is used at the Enikaev Metallurgical Works (EMW).Fiedler et al. [I] showed that the thermomechanical properties of refractory materials used for mixer linings permit a decrease in the present standard times for drying and heating the unit by a factor of 2 or even 3.Intensification of the drying and heating of the lining of a mixer complicates the conditions of its operation, because it is accompanied by an increase in the stress in the lining, induced by the unsteady temperature field. This makes it necessary to investigate the temperature and stress distribution in a lining layer operating at high temperatures.Gol'dfarb [2] examined the dynamics of heating of a multilayer lining of a mixer up to the steady state under combined first-and second-order boundary conditions. However, realization of the method requires the use of thermometers, the readings of which are less reliable than those of thermocouples.Using known equations we compile for the conditions of drying and heating of a mixer lining by the combustion products of coke-oven gas an equation of the thermal balance in integral form:where B is the flow rate of the fuel (m3/sec); * Q~, specific heat of combustion of the fuel (J/m3); Vg, amount of gaseous combustion products, depending on the elementary composition of the fuel and the excess air coefficient (m3/m3); twa , temperature of the waste flue gases at the mouth of the orifice for molten pig iron (~ Cg, mean specific heat capacity of the combustion products at constant pressure in the temperature range from 0 to twa (J/m3"K); gl effective radiative capacity of the inner surface of the mixer lining; Cs, coefficient of radiation of an absolute blackbody, equal to 5.67 W/m2"K~; F, area of the inner surface of the mixer lining (m2); ~g, mean temperature of the combustion products (K); Tlx=o, temperature of the inner surface of the mixer lining (K); x, a linear coordinate with respect to the lining thickness, the origin of which coincides with the working surface (m); Eg, equivalent absorption capacity of the combustion products at Tg; ag, equivalent absorption capacity of the combustion products at Tix=o ; ~c, coefficient of heat transfer by convection from the combustion products to the lining surface (W/m2"K); and Qf, heat flux from the mixer to the ambient medium (W).*Here and below the gas vo...

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