Effects of wood biomass type and airflow rate on fuel and soil amendment properties of biochar produced in a top‐lit updraft gasifier

In this study, the effects of biomass type and airflow rate on the fuel and soil amendment properties of a solid byproduct (biochar, BC) produced by gasification in a top‐lit updraft reactor are studied. The results indicate that biomass with the highest fuel value index produces BC with the highest quality as a solid fuel. The best properties as a soil amendment are reached by Gua‐30‐BC as follows: the cation‐exchange capacity (CEC) of 18.6 meq/100 g, the water holding capacity (WHC) of 438%, and the total oxidizable organic carbon (TOC) of 14.2%. When the airflow increases from 20 to 40 L/min, the properties of pine BC as a solid fuel are affected. An increase in the gasification temperature leads to a diminished bulk density. Moreover, the ash content increases affecting the heating value of BC, which decreases from 27.71 to 25.5 MJ/kg. The best properties of BC as a solid fuel are reached at 20 L/min. The properties of BC as a soil amendment are affected with increased airflow as follows: the CEC decreases by 22.8%, TOC increases by 232.3%, and WHC increases by 7.6%. The best properties of BC as a soil amendment are obtained at 40 L/min. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13105, 2019