Efficiency Improvement of Cupola Namphi Iron Ore Furnace by Using Automatic Control System

Abstract

Namphi iron ore smelting had been conducted with traditional method yielding inadequate quantity and quality of Namphi steel as demanded. Therefore, this research aims to improve efficiency of cupola Namphi iron ore furnace by using automatic temperature control system with 2 functions consisted of : 1) computer displaying operational status, processing, controlling operation, alarming for errors, and setting operatiosn that could be selected as manual or automatic modes; 2) microcontroller transmitting and receiving data from computer, i.e., receiving furnace temperature from Thermo Couple for transmitting to computer for processing and receiving commands from computer for controlling the speed of wind blower. The results revealed that parameters of PID Controller with proportional gain (Kp), integral gain (Ti) and the derivative gain (Td), that were appropriate for controlling furnace were 12, 0.6, and 0.05, respectively. From comparing efficiency of Namphi iron ore smelting by using cupola furnace controlled by manual mode and automatic mode with approximate 5 kilograms of Namphi iron ore, it was found that Namphi iron ore smelting by using cupola furnace controlled by manual mode approximately consumed 53.67 kilograms of charcoal that was lower than that of manual mode by 13.04% and it could smelt around 1.62 kilograms of Namphi steel calculated to be 32.33% therefore it had higher efficiency than that of manual mode by 11.4% from testing to find elements of Namphi steel by using Energy Dispersive X-ray Spectrometer (EDS), it was found that percentage of iron (Fe) and carbon (C) mixed in Namphi steel smelted from both modes had no statistical significance. When comparing economic wealthiest, it was found that smelting Namphi steel by using automatic mode provided profit of 3,922 baht per production cycle that was higher than that of manual mode by 1,791 baht whereas its break-even point was calculated to be 29 production cycles that was quicker by 8 production cycles.