Producción de biohidrógeno a partir de residuos agroindustriales del cacao (Theobroma cacao) mediante un proceso termoquímico

Abstract

Hydrogen is a clean and sustainable energy carrier that has great potential to become an alternative fuel; in turn, it enables diversification of the sector, energy transition and reduces dependence on fossil fuels. In recent years and due to the abundance of lignocellulosic residues, interest in energy production has grown. Among the emerging ways of generating energy is gasification, a process that involves the thermal decomposition of biomass to obtain combustible gases. Biomass gasification solves two current problems such as waste utilization and energy demand. In the present work, H2 was produced from the gasification of cocoa residues, Theobroma cacao. For this purpose, the characterization of the shell was carried out through a proximate and elemental analysis, as well as TGA and SEM analysis. On the other hand, the lignin content was determined, which was 41.5%. Subsequently, through technological monitoring, the process conditions were established, such as quantity and size of sample, gasifying agent, water/air injected. Finally, the gasification process was carried out in a prototype batch reactor with different stages occurring in a single tank. Gas quantification was determined through two gas analyzers, including CO, H2S, CH4, O2 and H2. The maximum H2 concentration present in the syngas was obtained with a ratio of 1.5 steam/biomass and air/biomass which was 1852 ppm, while the lowest H2 concentration was obtained with a ratio of 0.5; observing that both air and water vapor favor H2 formation. The results of this study indicate that cocoa husk is a suitable biomass for hydrogen production and can contribute to waste utilization and energy generation.