Non-linear interaction behavior of mixed industrial solid wastes in circulating fluidized beds: Reacting MP-PIC simulation

• A custom MP-PIC solver in OpenFOAM to simulate combustion of industrial solid wastes in a full-scale CFB. • Simulations of dynamic particle flow reveal how different solid waste fuels mix within the CFB. • Particle heat-transfer coefficients vary across the bed and fuels, revealing distinct spatial and inter-fuel behaviour. • Co-firing different waste types exhibits non-linear interaction effects that impact combustion efficiency and performance. Circulating fluidized bed (CFB) combustion presents a viable technique for the clean and efficient disposal of general industrial solid waste. However, the waste’s complex and variable composition and the limited observability of CFB dynamics complicate experimental studies. This research introduces a custom dense gas–solid reactive flow solver based on OpenFOAM, utilizing the Multiphase Particle-In-Cell (MP-PIC) method alongside combustion kinetics. Validation of this solver is achieved through comparison with cold-flow, reacting-flow, and industrial CFB data. Using the validated solver, the co-combustion characteristics of mixed solid wastes in CFBs are systematically examined. Results indicate that variations in fuel properties lead to unique combustion patterns. A higher biomass proportion enhances combustion in the dense bed (resulting in more CO and less O 2 ), whereas textile waste yields the opposite outcome. Interactions for different fuel manifest, such as nonlinear CO emission changes with textile content and non-monotonic heat transfer shifts as the sludge ratio increases. These insights elucidate critical thermal interaction mechanisms in mixed-waste combustion and provide a validated modeling framework for optimizing fuel blending strategies within industrial CFB systems.