Controlled performance and atmospheric emissions testing of a biofuel engine produced by hydrodeoxygenation of chicken fat waste with a <scp>Ni</scp> /tire carbon catalyst

Abstract BACKROUND Catalytic hydrodeoxygenation reactions of chicken fat allow renewable biofuel (CB) production with a high content of n ‐C 17 alkanes and diesel fuel‐like properties. Nickel catalysts deposited on carbon, obtained by combining wet impregnation and pyrolysis of used tires, demonstrated high efficiency in producing biofuels from chicken fat. The Box–Behnken design of experiments was used to determine the optimal combination of parameters for maximizing the yield of n ‐C 17 . Moreover, we evaluated performance and emissions in a four‐stroke, direct‐injection, CB40 vertical engine. Results The Ni/C9 catalyst achieved a conversion rate of 95.2% and a selectivity of 83.2% for the production of n ‐C 17 alkanes. The optimal conditions for obtaining the maximum yield of n ‐C 17 are 25 bar pressure, 8.91% Ni by weight, 339.2 °C, and 4.89 h reaction time. When comparing the performance of conventional diesel fuel with blends of CB biofuel and diesel, the blends containing 20% and 40% renewable biofuel (CB20 and CB40) resulted in a power loss below 0.6%. However, with CB40, emissions of CO, HC, NOx, and smoke were reduced by 19.6%, 21.8%, ca 4%, and 42.09%, respectively. Conclusion This study presents the synthesis, engine performance, and emissions test results of Ni/C catalysts using waste tire carbon and chicken fat waste. These catalysts yielded promising conversion and selectivity rates for the production of renewable biofuels. When blends of the biofuel with conventional diesel were used in a CB40 engine, significant reductions in pollutant emissions were observed, demonstrating its potential for industrial application. © 2026 Society of Chemical Industry (SCI).