Phase-segmented analysis of blackberry pomace convective drying: Mass transfer dynamics, exergy efficiency, and staged temperature guidelines Academic Article in Scopus uri icon

abstract

  • Valorizing high-moisture blackberry pomace is constrained by convective drying analyses that mask evolving behavior and hinder rational design. This study applied a phase-segmented framework to convective drying at 50¿90 °C, integrating kinetics, mass transfer, exergy, sustainability, and techno-economics. Five semi-empirical models were assessed; the Page model best described kinetics (R2 = 0.9964¿0.9992). Phase segmentation captured shifting controls, with Biot number (Bi), mass transfer coefficient (hm), and effective diffusivity (Deff) evolving, and activation energy rising from 19.22 kJ mol¿1 in phase 1 to 60.87 kJ mol¿1 in phase 3. Exergy analysis identified early efficiency peaks and late irreversibilities; peak ¿ex reached ~13¿16 % at 50¿80 °C and ~9 % at 90 °C, then fell below 1 % near completion, revealing recoverable outlet-air potential. Specific energy consumption decreased from 210.24 to 59.18 MJ kg¿1. Phase-resolved indicators yielded staged guidelines: 70¿80 °C (phase 1), 60¿70 °C (phase 2), and 50¿60 °C (phase 3) to limit losses and preserve efficiency. Sustainability improved with temperature (sustainability index (SI) 1.15¿1.99; CO2 9.00¿3.89 kg CO2 kg¿1 H2O). Techno-economic scenarios informed by energy savings and cost reductions suggested pay-back near 1.2 years under reduced demand. The framework clarifies mass- and energy-transfer mechanisms and delivers guidelines warranting validation via staged-temperature runs, supporting process refinement and control. © 2025

publication date

  • January 1, 2025

published in

  • LWT  Journal