Our future environmental leaders are studying the problems our planet is facing from climate change and innovating new ideas to reduce the carbon and other greenhouse gasses in our atmosphere. When our intern, Matthew Helms, shared with us a project he was part of to address the carbon releases associated with prescribed burns used to prevent wildfires and the potential of biochar, we asked him to share the project with our members.
Prescribed burns involve setting planned fires to maintain the health of a forest and to prevent destructive wildfires. Two types of burns are commonly used: Lighting fires across a tract of land and pile burning. Pile burning is used when conditions are unsafe for larger fires. Dead grass, fallen branches, dead trees, and other debris are collected and burned.
Scientists found that prescribed burns release significantly less CO2 than wildfires. According to a study funded by the NSF: Prescribed Burns May Help Reduce U.S. Carbon Footprint | NSF - National Science Foundation (nsf.org), "Prescribed burns can reduce fire emissions of Carbon Dioxide in the west by an average of 18 to 25 percent, and as much as 60 percent in certain forest systems."
Project: Biochar Kiln
By Matthew Helms
Biochar has the potential to sequester carbon for around 2,000
years. Recently, I worked with a group of college students tasked with exploring solutions to the global climate change issue. We settled on the idea of utilizing biochar. "What exactly is biochar?" you may ask. Biochar is burned organic matter quite similar to charcoal except it retains the majority of its carbon when it is formed. This means it does not release all of its carbon when combusted. Biochar is made by a process called pyrolysis which is achieved through burning in the absence of oxygen. Our group's idea is to create the optimal pyrolysis conditions for the production of biochar in a large, portable kiln-like system.
The image at left is a model of our biochar kiln. It has two chimney pipes at the top and rectangular holes at the bottom. Our biochar kiln could be easily used by forest service personnel in fire prevention programs. It could supplement controlled burns and utilize biochar to create a much cleaner way of fire prevention. A portable biochar kiln would reduce the amount of carbon released and still have wildfire prevention effects; thus keeping extraneous carbon dioxide out of our atmosphere.
The diagram above displays the proposed biochar kiln operation details. The biochar kiln would work as follows. First, the biochar kiln is transported and assembled in the desired forest location. Then, the kiln is loaded with dry, flammable forest foliage (an abundance of which is known to be on our forest floors.) The next step, in order to produce the best biochar, is critical. The biomass collected must be burned from the top down. To account for this, we designed our kiln to utilize this burning method in creating biochar. Once the forest foliage begins burning, the kiln is covered to promote the absence of oxygen for our system. We designed our kiln to have holes at the base so it can pull up the minimum amount of oxygen needed to keep the burn from going out. The final step is to allow the kiln to cool once burning is complete and remove the produced biochar.
This process, if done correctly, could be a tool in reducing carbon dioxide emissions. Biochar stores 70-80 percent of carbon and locks it away for 2,000 years. Through the use of biochar, we can sequester 2.5 tons of carbon just by converting four average-sized pine trees into biochar. This has the potential to store CO2 that would otherwise exit through decomposing plant biomass, and keep it from reaching our atmosphere for a long time. Over time, this could have a significant impact on our emissions problem. Additionally, biochar is a soil-enhancing product. A possible end source for the biochar could be putting it back into the forest. However, our group felt it would be better if the produced biochar was incorporated into farming, where it could increase agricultural production. Biochar aerates the soil, helps soil retain more water, and prompts microbe growth which can be beneficial for crop growth. Our group's next steps are to build a prototype and to begin testing our idea.
Please contact me if you have feedback or questions: Matthelms21@gmail.com
Matt Helms is a student at Northern Arizona University working towards a degree in Environmental Engineering and Chemistry. He is an intern at ClimateUnified.org working towards finding solutions to our climate change issues and helping educate our communities about them.
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