Experimental Study of Combustion Chamber Performance Utilizing Biochar from Empty Fruit Bunch (EFB) as Fuel with Variation in Excess AirTaufiq Bin Nur, Muhammad Zafran Hanif, Rulianda Purnomo Wibowo and Mariani SembiringE3S Web Conf., 519 (2024) 01001DOI: https://doi.org/10.1051/e3sconf/202451901001