RSM-Based Performance Optimization of Coal-Fired CFB Boilers for Energy Efficiency

¹ Mapúa University, School of Graduate Studies, 1002 Manila, Philippines
² Mapúa University, School of Mechanical, Manufacturing, and Energy Engineering, 1002 Manila, Philippines

^* Corresponding author: rlbdelrosario@mymail.mapua.edu.ph

Abstract

This study experimentally and numerically investigates the environmental and energy performance optimization of a 150 MW coal-fired circulating fluidized bed (CFB) boiler using Response Surface Methodology–Central Composite Design (RSM-CCD) in accordance with ASME PTC 4–2013. The analysis focuses on three key operational parameters—primary air flow, secondary air flow, and staging air distribution—and their effects on combustion efficiency, freeboard differential pressure (dP), and temperature stability. Reduced cubic regression models demonstrated strong predictive accuracy, with R² values of 0.5980 for combustion efficiency, 0.9342 for freeboard dP, 0.9628 for freeboard temperature, and 0.9789 for bed temperature, indicating robust model validity. Optimal conditions were achieved at 375 t/h primary air, 210 t/h secondary air, and 26%:42% upper-to-lower staging air distribution, resulting in a combustion efficiency of 99.94% and stable thermal profiles. Validation tests confirmed that all performance indicators were within 95% prediction intervals. The study highlights that RSM-based multi-objective optimization enhances energy efficiency, reduces emissions, and minimizes operational risks such as erosion and agglomeration. Integrating RSM with predictive control systems offers a sustainable pathway for improving the environmental performance of large-scale CFB plants and supporting cleaner energy production.