Research Article Analysis of the Effect of High and Low Calorific Value Coal Utilization on Process Efficiency in the RKEF Process

A Case Study at PT Aneka Tambang Tbk. UBPN Southeast Sulawes

Abstract

This study investigates the effect of using High Calorific Value (HCV) and Low Calorific Value (LCV) coal on process efficiency in the Rotary Kiln–Electric Furnace (RKEF) nickel reduction process at PT Aneka Tambang UBPN Southeast Sulawesi. The research was conducted quantitatively through laboratory-scale experiments and operational data analysis. Proximate analysis showed that the volatile matter (VM), fixed carbon (FC), and ash contents significantly influenced the gross calorific value (GCV) of coal. The results indicated that VM had a negative correlation with GCV, FC showed a positive correlation, and ash content exhibited a negative correlation, suggesting that higher FC and lower VM or ash improve coal energy performance. The comparison of HCV and LCV utilization demonstrated that LCV coal mass tends to fluctuate more (1500–3000 kg) compared to HCV coal (500–1500 kg), with total coal consumption ranging between 800–3200 kg. These variations reflect differences in coal quality and thermal efficiency during the RKEF process. Overall, optimizing coal selection based on calorific value and proximate composition is essential to maintain energy balance, improve reduction efficiency, and achieve cost-effective ferronickel production.