Biomass holds immense potential for replacing reliance on traditional fossil fuel sources, accounting for 73 percent of renewable energy production around the world. But crops grown for this purpose can harm both land and water, and divert farming from critical food production.
“Environmentally safe disposal of poultry excrements has become a significant problem. Converting poultry waste to solid fuel, a less resource-intensive, renewable energy source is an environmentally superior alternative that also reduces reliance on fossil fuels,” they said in a statement posted online earlier this month in Elsevier’s Applied Energy journal.
In the study, researchers from BGU’s Zuckerberg Institute for Water Research evaluated two biofuels – biochar and hydrochar – to determine which is the more efficient poultry waste solid fuel. They compared the production, combustion, and gas emissions of biochar, which is produced by slow heating of biomass at a temperature of 450°C (842°F) in an oxygen-free furnace with hydrochar. Hydrochar is produced by heating wet biomass to a lower temperature of up to 250 °C (482°F) using a process called hydrothermal carbonization (HTC.) This mimics the way coal is formed in a shorter time frame.
The results were clear, according to student researcher Vivian Mau, under the supervision of Professor Amit Gross, chair of the Department of Environmental Hydrology and Microbiology at Zuckerberg Institute. “We found that poultry waste processed as hydrochar produced 24 percent higher net energy generation,” she said in a statement. “Poultry waste hydorchar generates heat at high temperatures and combusts in a similar manner to coal, an important factor in replacing it as a renewable energy source.”
For the first time, researchers showed that higher HTC production temperatures resulted in a significant reduction in emissions of methane (CH4) and ammonia (NH3), with an increase of carbon dioxide and carbon monoxide.
“This investigation helped in bridging the gap between hydrochar being considered as a potential energy source toward the development of an alternative renewable fuel,” Prof. Gross explains, “Our findings could help significantly reduce greenhouse gas emissions associated with electricity generation and agricultural wastes. Field-scale experiments with HTC reactor should be conducted to confirm the assessments from this laboratory-scale study.”
The study, published in Elsevier’s Applied Energy, was made possible through funding from the Israeli Ministry of Environmental Protection, the Rosenzweig-Coopersmith Foundation, the Israeli Ministry of National Infrastructures, Energy and Water Resources, the Rieger Foundation and the Zuckerberg Scholarship Fund at BGU’s Zuckerberg Institute for Water Research.