Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : July 18, 2024
The introduction of solid biofuels to replace coal is expected in order to build a sustainable society. In this study, we focused on dry torrefaction (DT) and densified molding as methods for reforming solid biofuels. The purpose of this study is to investigate the effect of DT and densified molding conditions on the char yield and the absolute amount of char of solid biofuels. In the study, four types of solid biofuels are used, fuel-R (raw powder), fuel-DT (DT powder), fuel-RB (densified fuel from raw powder) and fuel- DTB (densified fuel from DT powder). To evaluate the absolute amount of char, EFC (enhancement factor of char) is defined as the ratio of the char mass of each fuel to the char mass of fuel-R. The results obtained are as follows. At the molding temperature of 100°C, the apparent density of fuel-DTB is lower than that of fuel-RB and decreases with DT temperature. The apparent density of fuel-RB and fuel-DTB increases with molding temperature. The effect of DT on EFC is not large, while the effect of densified molding on EFC is large. From the investigation on the relationship between EFC and apparent density of fuel-DTB, it is found that EFC is closely related to the apparent density, which means that the increase in EFC results from the suppression of volatile matter evaporation and the conversion of some of the volatile matter to fixed carbon.
