Simplifying pyrolysis: Using gasification to produce corn stover and wheat straw biochar for sorptive and horticultural media

• Gasification has many biochar processing advantages over pyrolysis via retort oven.
• Gasified straw and stover biochar is similar to retort-oven produced biochar.
• Gasified biochar is successful as a horticultural potting substrate.

Biochar is a renewable, useful material that can be utilized in many different applications. Biochar is commonly produced via pyrolysis methods using a retort-style oven with inert gas. Gasification is another method that can utilize pyrolysis to produce biochar. This method has significant processing advantages; it can be carried out in normal atmospheric conditions, eliminating the use of inert gas, is more amenable to scale up, and provides heat that can be used to generate power and/or help recoup processing costs. In this work, a simple gasification process using a top-lit updraft style cookstove was used to produce biochars from corn stover, wheat straw, and wheat straw treated with glycerin, which were then compared to biochars made using the more conventional retort oven pyrolysis process. The glycerin-treated wheat straw biochar from the gasification process had carbon content > 70% and an ash content of 25% which was equal or better than the same biochar produced using the retort oven. This biochar has also shown successful use as a peat moss replacement in horticultural applications. This shows that gasification is a simpler, more cost-effective means to produce biochars and should be considered for horticultural and other similar applications.