Blast furnace waste heat recovery: case study and optimization of finned-tube heat exchanger incorporating fouling model

Particulate fouling causes severe, time-dependent performance degradation in industrial heat exchangers, a factor often neglected in conventional optimization. This study demonstrates that fouling-resilient designs can be achieved by integrating a data-driven asymptotic fouling model, derived from six months of operational plant data, into a multivariable optimization framework. The optimization reveals an important design finding: strategically narrowing tube and fin pitches increases wall shear stress, which actively mitigates fouling accumulation and is key to enhancing long-term performance. This approach yielded optimized designs that improved the long-term net energy savings rate by 29 % and, for compact designs, the long-term volumetric rate by 98.4 % over the base case. Furthermore, an economic analysis identified a clear crossover point at 205 d, providing a practical framework for selecting optimal designs based on the intended operational lifespan to maximize economic returns. These findings highlight the importance of lifecycle-aware design for heat exchangers in harsh industrial environments. • A data-driven fouling model is integrated into heat exchanger design optimization. • Narrower tube and fin pitches mitigate long-term performance degradation. • The long-term design improves the net energy savings rate by 29 %. • Compact design optimization boosts the volumetric energy savings rate by 98.4 %. • The long-term design shows economic superiority after 205 days of operation.