Impact Of Dry Flue Gas Loss on Thermal Efficiency in Pulverized Coal Boilers

Abstract

Coal-fired power plants (CFPPs) dominate Indonesia’s electricity generation, contributing 67.2% of the national supply, yet they pose substantial challenges in terms of energy efficiency and environmental impact. Boilers, as the largest energy-consuming component in CFPPs, play a critical role in determining overall plant performance. This study aims to improve the thermal efficiency of a 315 MW subcritical pulverized coal boiler by optimizing two key operational parameters: excess air and flue gas temperature. Using actual field data and heat loss-based calculations following standardized energy audit methodology, the study quantifies the efficiency gains achievable through modest adjustments. The results show that a 5 °C reduction in flue gas temperature leads to a 0.31% increase in boiler efficiency, while a 5% reduction in excess air improves efficiency by 0.29%. These findings underscore the significant impact of controllable combustion parameters on energy performance and highlight low-cost opportunities for efficiency enhancement. The study not only identifies the sensitivity of boiler efficiency to excess air and flue gas temperature but also offers practical insights for operational optimization. Implementing such measures can reduce fuel consumption and operating costs while contributing to emission reduction, thereby supporting a more sustainable and cost-effective operation of coal-fired power plants in Indonesia.