A research team from Iowa State University is one of the XPRIZE $1 million award receivers announced on April 22nd. The Bioeconomy Institute Carbon Removal Team has developed a demonstration-scale pyrolyzer that sequesters carbon dioxide via biochar. The system also produces bio-oil as a by-product that can replace diesel fuel.
According to leading experts from the Iowa State University’s Bioeconomy Institute – Robert Brown – distinguished professor in Engineering, and the Gary and Donna Hoover, chair in Mechanical Engineering and co-director of Iowa State’s Bioeconomy Institute, the XPRIZE prize validates the research team’s approach to carbon sequestration called pyrolysis.
Pyrolysis involves heating biomass in the absence of oxygen which produces a carbon-rich material known as biochar – a form of charcoal. The idea is for the CO2 to be stored in a solid form rather than risking it being released into the atmosphere.
Biomass stores CO2 while vegetation is growing but when it decays or is burned for energy, it releases the same amount of carbon dioxide that it has sequestered naturally during its lifetime.
The biochar is storing the CO2 providing a tool to keep away carbon from being released into the atmosphere. Biochar is then added to the soil where it is supposed to stay there for centuries to millennia. It also improves soil health and crop yield which further increases the carbon storage potential of soil naturally and it can replace fertilizers.
The bio-oil produced from the process could also be refined into renewable diesel fuel or bio-asphalt which is a renewable substitute for petroleum-based asphalt.
The Bioeconomy Institute Carbon Removal Team currently has two pyrolyzers – a lab-scale unit installed on campus in the Biorenewables Research Laboratory and a larger pilot-scale unit at the BioCentury Research Farm outside Ames.
The team has also partnerships with Stine Seed Company – the largest independent seed company in the US and Frontline Bioenergy – renewable products company, to build a demonstration-scale pyrolyzer near Redfield, Iowa, northwest of Des Moines.
The new pyrolyzer is slated to come online this summer and will be capable of capturing and storing the equivalent of over 1,000 tons of carbon dioxide a year.
The process also requires heating to produce the biochar. However, the team innovated and made it self-heating which improves its cost-effectiveness and environmental performance.
According to the researchers, the “auto-thermal pyrolyzer” works by pumping a small amount of air into the reactor, which causes some of the products of pyrolysis to partially oxidize and give off heat.
The carbon removal team plans to run for the larger award from XPRIZE of up to $50 million that will be determined in 2025. It aims its invention to combat climate change by showing biochar as an effective means of storing carbon in the soil and thus keeping it away from the air.