Waste to energy: performance evaluation of a bubbling fluidized bed gasifier using biomass blends and facemask

Rapid industrialization and population growth in developing countries have increased energy demand, emphasizing the need for sustainable alternatives. Growing environmental concerns have increased interest in thermal conversion methods such as pyrolysis, co-pyrolysis, and biomass gasification for converting agricultural and municipal wastes into clean energy. This investigation examines the impact of the Equivalence Ratio (ER) on Carbon Conversion Efficiency (CCE) and resultant syngas composition across various feedstocks within a Bubbling Fluidized Bed Gasification (BFBG) system. Computational Fluid Dynamics (CFD) simulations were performed to analyse gas–solid hydrodynamics. CFD analysis indicated that lighter feedstocks, such as rice husk, migrated to the freeboard region at 0.4ER, whereas denser materials, including groundnut shell and wooden shavings, remained concentrated in the mid-bed zone, resulting in enhanced gasification reactions. Experimental results revealed that increasing the ER enhanced hydrogen and methane concentrations across all feedstocks. Groundnut shell achieved 6.4 % H2, 5.6 % CH4, a gross calorific value (GCV) of 4.6 MJ.m−3, and a CCE of 83 % at 0.4ER. In contrast, rice husk showed minimal improvement with 3.6 % H2 due to its high ash content and exhibited the lowest CCE of 35 %. Wood shavings displayed moderate gasification performance with 4.4 % H2 and 4.2 % CH4. The surgical face mask demonstrated superior performance, producing 17.6 % H2 and 9.4 % CH4 at 0.4ER, with a high-calorific syngas (8 MJ·m−3GCV), confirming its efficiency as a waste-to-energy feedstock. The correlation between CFD predictions and experimental data validated the reliability of the model and its applicability for optimizing feedstock utilization in sustainable thermal energy generation.