Investigating performance of compound heating furnace subject to heating by two elements, high alumina insulation and silicon control rectifier (scr) system at 1600ᴼc

Abstract

The present study examines the performance of a resistance heating furnace using two different heating elements, Silicon Carbide (SiC) heating rods and Molybdenum Di-Silicide (MoSi2) heating elements, where SiC rods are used first, starting from the beginning (ambience) temperature of 35ᴼC up to 1300ᴼC, followed by MoSi2 heating elements to raise the chamber temperature from 1300ᴼC to the set temperature of 1600ᴼC. To achieve effective insulation results, newage high alumina (Al2O3), very low thermal conductivity (K), and high density materials such as zirconium tiles, mullite tiles, and zirconium modules, all with such necessary insulation properties sandwiched, are used. Air, a bad conductor of heat transfer, is also used in a gap of 20 mm between two different tiles to lessen heat transfer from the working chamber towards the outer ambience by conduction and radiation to achieve desirable results-maximum thermal efficiency with the least heat loss from the outer surface and to achieve skin temperature equal to the ambient temperature. Also, in this experiment, hot-faced red bricks are used under the hearth in a new design. The system under study consists of a programmable Proportional Integral Derivative (PID), a thyristor power pack, recrystallized alumina tubes, and sensing elements: a thermocouple and Pt-Pt/13%. Rh, semiconductor-based circuit that controls power and current. This makes the system to meet the requirement (step down) and thereby controls voltage automatically with a transformer (depending on the size of the working area, 53 A (I), 220 V for single phase, reduced to 60 V by a step down transformer) auto-current-limiting facilities.