Critical Fouling Resistance in Heat Exchanger Energy Efficiency in Phosphoric Acid Concentration: An Industrial Plant Aspen Plus Simulation-Based Approach

Fouling in heat exchanger tubes leading to additional thermal resistance, which results in higher thermal losses, has a significant impact on the energetic performance of phosphoric acid concentration (PAC) units. Using actual industrial data over a 22-day production cycle, an Aspen Plus simulation was used in this study to assess the effect of fouling resistance on important parameters, such as heat duty (Q), PA exchanger energy consumption (EPAEX), and PAC unit energy consumption (EPAC). Beyond a critical fouling resistance of 0.0003 m2 · K · W−1, the results show an apparent change in slope in these parameters, indicating a significant increase in thermal losses. The convergence of these functions provides a cross-verification of their validity. These results offer a valuable foundation for PAC unit operation optimization by identifying the optimal runtime prior to fouling.