Development of Mathematical Model for Specific Power Consumption of Resistance Furnaces at Non-Ferrous Metallurgy Enterprises

As a result of the energy inspection (energy audit) at a large non-ferrous metallurgy industrial enterprise, the following most effective controlled load consumers (CLC) of power were identified: rotary batch resistance furnaces (RBRF), tube resistance furnaces (TRF), electrolysers, auxiliary CLC (furnace calcinations, muffle, carbidizations and welding machines). The paper presents the results of studies of heat-and-power characteristics of tube resistance furnaces during their heating and cooling periods. Mathematical models are obtained in the form of trend equations for the temperature of the furnace thermal zones with high determination coefficients. The histograms of power frequency distribution in the static (stationary) mode of operation of tube furnaces have been constructed. The null hypothesis H0 has been checked for asymmetry and kurtosis, for Pearson criterion and Kolmogorov-Smirnov's fitting criterion, confidence intervals have been determined for estimating the average value, variance and standard. The use of tube furnaces as CLC of power during peak hours of the day (disconnection of the CLC for the period of maximum load) implies the disconnection of the furnace thermal zone during this period. The obtained actual temperature value exceeds the lower limit of technological protection, which confirms the efficiency of the use of tube furnaces as CLC of electric power and allows one to reduce the maximum load by 10 kW. In the course of the full factorial experiment (FFE), mathematical dependence models of the specific electric power consumption on technological factors were obtained. The results of the conducted FFE allowed to increase the loading and to reduce the consumption of hydrogen in the tube furnaces. The lots of powder obtained after the FFE were verified for compliance with the requirements of technological regulations (technological protection) by the department of technical control (DTC), the central factory laboratory (CFL), the metallography of the non-ferrous metallurgy enterprise. The results of the inspection showed that the powder obtained corresponds to the requirements of the technological regulations.