Location: Commodity Utilization ResearchTitle: Biochar characterization and a method for estimating biochar quality from proximate analysis results
Submitted to: Biomass and Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2016
Publication Date: 1/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5574048
Citation: Klasson, K.T. 2017. Biochar characterization and a method for estimating biochar quality from proximate analysis results. Biomass and Bioenergy. 96:50-58.
Interpretive Summary: Charred biomass (biochar) can improve soil quality and capture carbon. Groups in the United States and Europe have published standards for the quality of the biochar. The standards use expensive chemical methods to determine the makeup of the biochar. In this manuscript, we try to see if an alternative cheaper method could be used to determine the makeup of the biochar and if this method would work with the standards for biochar quality and biochar longevity. The results were successful and the alternative method worked for biochars that had been charred at temperatures of 400°C and above. It was also shown that the alternative method could be used to estimate the longevity of biochar when added to soil.
Technical Abstract: Biochar has gained significant interest in the literature, mainly for its ability to improve soil quality and sequester carbon while potentially providing energy during its manufacture. Organizations in the United States and Europe have proposed standards and classifications based on total carbon content and hydrogen-carbon mol ratios. In addition, indices have been developed to estimate the potential for biochar in retaining its carbon for sequestration purposes, with several of these correlating to biochar composition values. This work reviewed available proximate analysis data and used these data to correlate biochar composition with biochar classification and sequestration potential. From this analysis, biochar carbon content could be correlated to volatile matter (VM), fixed carbon (FC), and ash (ASH) by the relationship C = 0.474×VM+0.963×FC+0.067×ASH. Biochar oxygen content was well correlated to a similar relationship, while hydrogen was best correlated to a relationship with VM, FC, and VM/FC. Atomic ratios, such as H:C and O:C, used for biochar classification and carbon sequestration potential were best correlated to VM/FC. The developed correlations were proven to accurately classify biochar classification when the biochar had been made at 400°C and above.