Agradecimentos: The authors are grateful for the support of the Brazilian federal agencies The National Council for Scientific and Technological Development (CNPq/Brazil project number 458412/2014-7, 303742/2017-8), The Coordination for the Improvement of Higher Education Personnel (CAPES/Brazil - Finance Code 001) and the Institutional Internationalization Program (CAPES-PrInt project number 88887.310560/2018-00). J. L. F. Alves gratefully acknowledges the postdoctoral fellowship from National Council for Scientific and Technological Development (CNPq/Brazil Process 152461/2022-1). The authors are also grateful for the XRF analysis provided by the National Institute of the Semi-Arid (INSA/Brazil) Ver menos

Abstract: The abundant generation of pokan (Citrus reticulata) peel, passion fruit (Passiflora edulis), and pineapple (Ananas comosus) peel wastes in Brazil, estimated at 1.01 million tons, presents an opportunity for exploration. Based on our prior studies and relevant literature, these Brazilian agro-wastes possess significant potential due to their composition and inorganic components, indicating the ability to produce a substantial amount of H2 through steam gasification and aligning with the emerging trend of the circular economy. The originality of this study lies in its contribution to the field by providing pioneering insights into the kinetics of the steam gasification reaction, energy characteristics, and synthesis gas composition derived from these Brazilian agro-wastes. For this, pyrolysis followed by steam gasification experiments were performed utilizing a magnetic suspension thermobalance, and subsequent analysis of the products was conducted using a gas chromatograph. Initially, it was observed that pineapple peel waste had the highest carbon yield in the biochar, while pokan peel and passion fruit had similar carbon yield and low O/C and H/C ratios for all biomass-derived biochar. The kinetic study showed that from the five models, just the modified random pore model provided a satisfactory fit for the experimental data, with activation energy values ranging from 43.37 to 83.04 kJ mol-1. The gas analyses showed that the H2 was over 60%, while CO ranged from 9.97 to 12.38%, and the H2/CO ratio was higher than 4.6. Pineapple peel waste also showed the highest yield of H2, lower heating value, and conversion efficiency when compared to the other types of biomasses studied. In this context, Pineapple peel waste was the most suitable for gasification due to its base-to-acid ratio, although it had a higher probability of producing ammonia. Future studies should address limitations in the application of evaluated biomasses in gasification reactors, including product distribution during scaling-up, potential slag formation, low energy conversion efficiency, and the need for experimental validation of theoretical models. These perspectives will contribute to the advancement of research and the development of applications in this field. Overall, this study provides insights into the potential for converting agricultural waste into valuable products, which could contribute to sustainable development and reduce environmental impacts Ver menos