Abstract
Regional deployment of bioenergy and bio-based products is often constrained by the seasonality, heterogeneity, and dispersed availability of lignocellulosic biomass. This work demonstrates a computer-aided process engineering (CAPE) workflow that integrates experimental characterization, process modeling, and life cycle assessment (LCA) to support regional symbiosis design using mixed feedstocks from agriculture and forestry. A case study is developed for Tanegashima, a remote Japanese island where unused woody residues and sugarcane bagasse are locally available but temporally mismatched. Torrefaction is modeled in an autothermal configuration: char is the main product, while torrefaction gas and condensables are recovered for internal heat supply and any excess is treated as an energy coproduct. Laboratory measurements (220-400°C, 20°C interval) provide temperature-dependent yields of char, tar, aqueous condensate, and gas, alongside ultimate analysis and heating values of solids and representative gas composition. These data are translated into a mass-energy inventory for LCA foreground modeling up to pelletization. The functional unit is 1 t of wet biomass (40 wt% moisture) processed on-island. Results show that increasing temperature decreases solid yield but increases charification and heating value. Autothermal operation becomes feasible above approximately 340°C under a mid-level drying-energy assumption, and the threshold is highly sensitive to drying performance. Across assessed feedstocks and temperatures, life-cycle GHG emissions are negative when credits are given for substituting fossil coal and kerosene-equivalent fuels. The proposed workflow enables composition- and seasonality-aware screening of regional biomass portfolios under consistent inventory assumptions.