Production and characterization of biocarbon from woody biomasses produced at 1000 °C

Controlled pyrolysis experiments have been performed on five different biomass types that include birch and spruce woodchips, wood pellets, steam exploded pellets and birch bark. Biocarbons have been produced at a temperature of 1000 °C at a slow heating rate of 10 °C/min. The focus of this work was to study and compare the characteristics of the produced biocarbons. The properties of the biocarbons were evaluated in terms of proximate and ultimate analyses, ash composition, SEM-EDX, Raman, XRD, density, and abrasion strength. In addition, the gas release and element distribution across the different pyrolytic products from pyrolysis of the studied biomasses are reported. The results showed that the yield and physio-chemical properties of the produced biocarbons differ across the tested materials. The bark biocarbon has the lowest fixed carbon and carbon content, in comparison to the other tested feedstocks. On the other hand, the bark biocarbon has a considerably higher ash content compared to the other biocarbons. The presence of ash-forming elements in the bark biocarbon was confirmed by SEM-EDS and XRD analysis, which are dominated by Ca and Si. SEM analysis also revealed that biocarbon produced from the birch and spruce wood have cellular and porous structure, whereas the biocarbon produced from the wood pellet and steam exploded pellets have much more dense and compact structure. Raman analysis results indicate that birch bark biocarbon has less ordered carbon structures. Abrasion test results showed that the birch bark biocarbon has poor mechanical properties and tends to fragment and break, forming particles and fines with small sizes. The biocarbon produced from the steam exploded pellets has superior mechanical strength with the least formation of fines compared to the other studied biocarbons.