Optimization of Oxygen Parameters for Determination of Carbon and Nitrogen in Biochar Materials

Abstract

Recently, there has been increased focus on biochar materials due to their ability to sequester carbon for long-term in soil. In the production of biochar or charcoal, plant biomass is heated in a low or no oxygen environment. This process results in a product with unique characteristics. But there is limited research on the standardization of methods for determining total carbon (C) and nitrogen (N) in the biochar materials whose properties vary by feedstock type and pyrolytic conditions. The objective of this study was to determine the oxygen dosing time (OT) and dose (OD) for total organic carbon (TC) and nitrogen (TN) analysis in biochar materials by dry combustion method (using Vario Max CNS analyzer). Central composite rotatable design was used to determine the effect of five levels of oxygen dosing time (OT) and dosing level (OD) on measurement of total carbon and total nitrogen in four types of plant originated biochars. OT and OD level interaction had significant impact on the measurement of TC and TN in all types of biochar materials. Optimum levels of OT and OD were determined as 103 to 110 sec and 180 to 232 ml/min, respectively.

Keywords:

• Biochar
• Carbon
• Corn stover
• Feedstock
• Nitrogen
• Oxygen dosing time
• Oxygen rate
• Ponderosa wood chips
• Prairie cordgrass
• Switchgrass
• Vario MAX CNS analyzer

Acknowledgments

This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-67009-30076 from the USDA National Institute of Food and Agriculture.

Notes

Note: Optimum conditions were obtained from ridge analysis.