Comparative performance of cubic and cylindrical graphite heat exchangers: A study using computational fluid dynamics

Graphite towers, a type of graphite heat exchanger (HX), are extensively utilized in the chemical and steel industries for heat exchange between corrosive fluids. These towers are available in various sizes and geometries, primarily cylindrical and cubic. This paper presents a novel computational fluid dynamics simulation of graphite elements, and the results show that cubic block exchanger has a better performance comparing the cylindrical one. It also examines the performance of graphite towers constructed from these elements. This study reveals the overall coefficient of heat transfer in a cubic tower with a side equal to the diameter of a graphite cylinder is 9% higher than that of a cylindrical tower. Consequently, the temperature difference between the inlet and outlet of the process fluid in the cubic tower is 37% greater than in the cylindrical tower. However, the pressure drop of the service fluid in the cubic tower is 2.4 times the same fluid in the cylindrical tower. Analyzing individual graphite elements indicates that the exit temperature of the process fluid in the least efficient cubic model surpasses that of the most efficient cylindrical model by 2.6%. These findings underscore the superior heat transfer capabilities of cubic graphite towers despite the increased pressure drop, offering valuable insights for optimizing the design of graphite HXs. This study investigates the influence of graphite block geometry on heat transfer, addressing a gap in previous research. By systematically analyzing various geometric configurations, we present novel calculations of pressure drop and temperature profiles, offering deeper insights into the interplay between geometry and thermal performance.