Assessment of the grindability and component variation of torrefied agricultural wastes for industrial furnace application

The utilization of agricultural solid biowastes is essential for resource saving and bioenergy conversion. By this way, the demand of industrial furnace for biomass would be compensated, and the energy structure would also be greener. Among them, torrefaction is a hopeful technology for solid biofuel production. This study investigates the grinding performance of torrefied biochar to achieve the grindability and component variation analysis of torrefied agricultural wastes for fluidized bed boiler, and thus realize pulverized biochar injection for industrial application. Totally crystallinity index (CrI), average particle size distribution, energy input for grinding process, component analysis, and elemental carbon state are adopted and analyzed around Hardgrove grindability index (HGI). The values of HGI are in the range of 45-120, 45-105, 60-120, and 60-135, respectively. The results indicate that torrefaction is conducive for biochar properties upgrading, especially for a higher temperature, and thus contributes to a higher HGI, lower particle size and grinding energy input, as well as better elemental carbon state. The produced powder from torrefied biochar is highly correlated to torrefaction temperature and biochar component, and thus leads to an excellent industrial application potential. Overall, this study is conducive for the agricultural biowastes conversion and solid biofuel production.