Modeling and Optimization of Thermal Stability and Heat Release Capacity of Waste Mixtures with Biomass Residues (Chlorella vulgaris)

This paper investigates the thermal behavior of binary mixtures composed of spent biomass of Chlorella vulgaris (CHo) and various types of waste, using thermogravimetric analysis (TGA) and micro-combustion calorimetry (MCC) in both oxidizing (air) and inert (nitrogen) atmospheres. The results showed that the nature of the waste and the type of atmosphere strongly influence the degradation processes. In air, mixtures with lignocellulosic (CHo-G) and textile (CHo-T) components favored complete oxidation, characterized by early ignition, low residue, and moderate thermal stability. In nitrogen, the CHo-A and CHo-P mixtures exhibited efficient pyrolysis, with lower decomposition temperatures (Ts) and reduced amounts of residue. From an energy perspective, CHo-P mixtures exhibited the highest calorific parameters (HRC and THR), which makes them suitable for direct energy recovery applications. Influence score analysis confirmed the superior performance of CHo-G mixtures (3.35–3.56), due to synergistic interactions between algal biomass and woody compounds. In contrast, CHo-C mixtures exhibited low energy efficiency and modest thermal behavior. The conclusions emphasize that the selection of waste type and working atmosphere is essential for optimizing thermochemical conversion, highlighting the potential of CHo mixtures for sustainable energy recovery applications.