Paper Title
Design Analysis and Modification of Combined Deaerator-Thermal Buffer Tanks for Process Using Thermic Fluid

Abstract
Due to increasing trend of adopting thermal oil as heat transfer fluid in variety of processes, the service life and ability to transport the required thermal energy to the process become the important factor to ensure the system performance. So far, the quality of such heat transfer fluids had been developed quite satisfactory but the operational problems could be emerged typically from the improper design of related expansion tank system and/or operational procedures. This research so aimed to investigate the hydrodynamics and heat transfer behavior of the thermal oil within the expansion tank system comprising of the deaerator-thermal buffer tanks and upper storage expansion tank. Also, the influence of modification of shape or aspect ratio of such tanks on the oil temperature when exposing to air was studied. A commercial (Fulton) expansion tank system was adopted as the prototype and created as the finite-element computational domain for such purposes. Under average practical operating condition, the thermal oil i.e. Therminol®66 at 140˚C with flow velocity of 3 m/s was applied as generic case of the investigation. The simulation results showed that the combined tanks with smallest diameter i.e. -40% reduction exhibited the lowest thermal oil temperature that less than 40˚C while all the cases also kept the oil temperature below the recommended value of 50˚C. Keywords - Thermal oil system, Expansion tank, Thermal buffer tank, Oxidation degradation