Technical concept and process modeling of a pilot-scale fluidized bed conversion facility

Abstract

Fluidized bed technology offers excellent heat and mass transfer that enhances reaction efficiency and product quality during thermochemical conversion. In this study, a pilot-scale integrated combustion–pyrolysis fluidized bed facility was evaluated, where heat from oil shale combustion is used for biomass pyrolysis. The system provides several unique advantages, such as fewer startup issues, shorter residence time, and uncomplicated configurations. Process simulation was performed in Aspen Plus, followed by workflow development, model validation, sensitivity analysis, and performance evaluation. Two integrated processes (oil shale combustion and biomass pyrolysis) were simulated, and the outputs (flue gas composition and product yield) were validated against experimental data. Comparable results confirmed the predictability of the developed simulation workflow. Flue gas results showed that the CO₂ fraction was approximately 20 % during air combustion of oil shale, but increased to 80–90 % under oxyfuel conditions. The maximum bio-oil was yielded (35.17 wt%) at450 °C, while higher temperatures favored non-condensable gas release. Energy and exergy analyses indicated that oxyfuel combustion improved overall energy efficiency from 65.14 % to 67.78 % and exergy efficiency from 27.55 % to 31.09 %, respectively. The study comprehensively demonstrates the feasibility of the pilot-scale combustion-pyrolysis facility and provides guidelines for future commissioning campaigns.