Heat transfer studies at supercritical conditions

The behavior of supercritical fluids is very different from normal fluids particularly in terms of its properties which has beneficial effects for several applications. Thus, hydrothermal gasification/liquefaction of biomass at near and above supercritical conditions is rapidly gaining its importance due to less/no evaporation losses of water and the solvent effects of water at such conditions. Though a lot of research has been done on heat transfer studies in supercritical fluids typically for cooling nuclear power plants very limited number of studies are available for supercritical water gasification of biomass. Several empirical correlations were reported in the literature for predicting the heat transfer coefficients. In this study, we have particularly investigated different correlations like Dittus-Boelter, Sieder and Tate and Krasnoshchekov-Jackson which are then validated with the experimental data using different fluids (air, CO₂ and water) and conditions with bench and pilot scale facilities. Though, heat exchange behavior with different fluids was studied herein we only focus on the supercritical water.