Thermal Modeling and Computational Simulation of Cooling Towers for the Separation of Light Hydrocarbons Application in LPG Distillation

Background: Cooling towers are critical components in industrial light hydrocarbon separation processes, such as liquefied petroleum gas (LPG) distillation, where their thermal efficiency directly influences the effectiveness of propane and butane condensation. Objective: The objective of this study is to develop a validated thermal and computational simulation model to evaluate and compare the performance of four configurations of natural draft, induced draft, cross flow, and dry-wet cooling towers in an LPG distillation plant, considering thermal efficiency, energy consumption, water losses, and operating cost. Method: An analytical-computational approach based on mathematical models and simulations in Python (v3.10) was implemented, using the NumPy and SciPy libraries. The simulations considered a thermal load of 4861.11 kW, a water flow rate of 279 m³/h, and constant environmental conditions (25°C, 60% relative humidity). The model was validated using the Merkel equation, the NTU method, conservation of mass and energy, and consistency with literature trends. Results: The natural and induced draft systems achieved the highest thermal efficiency (71.43%), while the cross flow and hybrid tower obtained 60% and 55.72%, respectively. The natural draft presented the lowest annual operating cost (20,497 USD/year) due to its zero-energy consumption, despite its high land footprint. The hybrid tower reduced water losses by 37% compared to the induced draft, although it incurred a higher energy cost. Conclusions: The developed model allows a comprehensive evaluation for the selection of cooling technologies, demonstrating that natural draft is the most efficient and economical option in operational terms, while hybrid towers offer water advantages in shortage contexts. These results support technically, economically, and environmentally sustainable decision-making in the petrochemical industry.