Evaluation of Air Inlet Configuration's Effect on Biochar Properties From African Mesquite Pod Carbonization

ABSTRACT The suboptimal efficiency of current biomass conversion processes necessitates the optimization of biochar production methodologies to enhance desired biochar characteristics. In this study, an investigation was conducted to determine the optimal air inlet configuration within a top‐lit updraft gasifier system for enhancing biochar properties from African mesquite biomass. The conversion process, lasting 130 min, utilized three distinct carbonization chambers, each engineered with varying air inlet orifice diameters of 1 mm (PA 1), 1.5 mm (PA 1.5) and 2 mm (PA 2), to evaluate the influence of air inlet geometry on biochar production. The key findings revealed that biochar yields were 53.2% (PA 1), 49.4% (PA 1.5) and 48.1% (PA 2), demonstrating an inverse relationship between yield and orifice diameter, while Fourier‐transform infrared spectroscopy (FTIR) analysis indicated that increasing the gasifier air inlet size modified the relative abundance and distribution of specific functional groups within the biochar. Additionally, enlarging the air inlet diameter led to greater surface area and pore volume in the produced biochars, and facilitated the development of a more porous and heterogeneous surface morphology. Thermal stability of biochars also improved with increasing diameter, with higher diameter‐sized gasifiers generally showing optimal qualities for improving biochar properties.