Microwave drying as an energy-efficient fuel pre-treatment and its cogeneration-level implications for sugarcane bagasse

Abstract

High moisture content limits the efficient bioenergy utilization of sugarcane bagasse (SCB) by reducing its calorific value and cogeneration performance. This study systematically compares microwave and convective oven drying as pre-treatment strategies through controlled experiments conducted in triplicate under varying power levels (100–600 W), temperatures (50–110 °C), sample masses (1–5 g), and initial moisture contents (30–67%, wet basis). Drying kinetics, effective moisture diffusivity (D_eff), and drying efficiency were evaluated using Fick's second law and energy balance analysis. Microwave drying reduced moisture from 67% to equilibrium within ~4 min at 600 W, compared to ~45 min for oven drying at 110 °C. Microwave treatment achieved higher D_eff (1.53 × 10⁻⁷–3.88 × 10⁻⁷ m²/s) and drying efficiency (up to 47.4%). The enhanced internal heating mechanism in microwave dryer significantly improved moisture migration and reduced drying time, demonstrating its potential for energy-efficient biomass pre-conditioning in cogeneration systems.