Refrigerant Hydrate Technology for Efficient Juice Concentration

This study demonstrates the feasibility of concentrating fruit juice using a refrigerant-based hydrate technology. Refrigerant hydrates, known for their moderate phase equilibrium conditions, have been proposed as promising candidates for a hydrate-based juice concentration. However, the commercial viability of this approach has been hindered by low dissociation efficiencies and lengthy hydrate formation times. Here, we investigate the effects of bitter melon juice on the formation and dissociation of 1,1,1,2-tetrafluoroethane (HFC-134a) hydrates, focusing on phase equilibria, gas uptake, dissociation enthalpy, and dissociation behavior. Experimental results reveal the thermodynamic viability of HFC-134a for hydrate formation in pure water and juice solutions with varying water cuts (96.5–98.3 wt %). The inhibitory effects of juice, reflected in the equilibrium curve shifting to higher pressure regions and reduced gas uptake, are attributed to the enrichment of dissolved solids during hydrate formation. Temperature dependence in dissociation enthalpies, calculated using the Clausius–Clapeyron equation, further underscores the suitability of HFC-134a. These findings establish HFC-134a as a promising candidate for hydrate-based juice concentration and provide critical insights for designing and operating efficient HFC-134a, hydrate-based processing systems.