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Professor’s Research Enhances Biogas Production

A $2 million grant awarded by the state of Ohio’s Third Frontier Advanced Energy Program to boost the amount of biogas produced from waste has, at its core, technology developed by a faculty member in Food, Agricultural and Biological Engineering.

Yebo Li, an assistant professor at Ohio State’s Ohio Agricultural Research and Development Center, will receive close to $1.5 million to continue research as a subcontract of the grant, which was given to Cleveland-based quasar energy group (formerly Schmack BioEnergy). Other collaborators include Ohio State’s Ohio BioProducts Innovation Center as well as Rockwell Automation, Seaman Corp., seepex and McCabe Engineering.


Yebo Li and Clemens HaleneAssistant Professor Yebo Li (left) shows the solid state anaerobic digestion tests to Clemens Halene, vice president of engineering of quasar energy group, in Li’s lab at Ohio State’s Ohio Agricultural Research and Development Center.The system combines a liquid biodigester, which processes wastes such as manure and sewer sludge, and Li’s “solid-state” digestion technology, which allows for the production of methane from various sources of cellulosic biomass, such as yard trimmings and crop residue.The main purpose of the award is to help commercialize an integrated anaerobic digestion system dubbed iADs, which can cost-effectively produce clean energy from both solid and liquid organic wastes through anaerobic digestion — a process in which microorganisms break down organic matter and yield biogas, in the absence of oxygen, inside a biodigester. Biogas can be used to generate electricity and thermal heat; it can also be cleaned, separated and dried to produce natural gas, or compressed to fuel automobiles.

Li, who also is a specialist with Ohio State Extension, has a patent pending for his technology.

The Third Frontier funds will make it possible for quasar to demonstrate iADs technology at its flagship biogas facility being built on OARDC’s Wooster campus, adding a solid-state digestion system to its liquid biodigester. The integrated system will be able to process more than 30,000 wet tons of biomass annually with an excess of 750 kW of electrical generation capacity.

Anaerobic digestion has been used in the United States for years to treat manure and sewer sludge and to produce methane for various energy applications. What’s new about the iADs is its potential for significantly enhancing biogas production and making this technology more economically feasible for large renewable energy generation in places with large biomass resources — such as Ohio. Adding Li’s solid-state digesting technology to a liquid biodigester could double the system’s biogas production capabilities.

“Biogas comes from the solids present in the anaerobic digestion process,” explains Li, who began collaborating with quasar after the company established its engineering office and a lab on the OARDC campus in 2008. “Current liquid-phase anaerobic digesters used in the United States can only process up to 14 percent solids content. My system has been successfully tested with 20-40 percent solids content, substantially increasing biogas production efficiency compared to existing systems.”

Li has been able to boost biogas production in the solid-state anaerobic digester by treating solid waste with effluent left over from the liquid anaerobic digestion process. This effluent is rich in the type of microorganisms that help break down solid organic matter during biodigestion.

His technology, Li said, results in several benefits: “More biogas can be produced, various sources of cellulosic biomass can be incorporated into the anaerobic digestion process, the need for effluent management is eliminated, and the solids that are leftover in the process can be sold as natural fertilizer.”

Mauricio Espinoza is an associate editor at Ohio State’s Ohio Agricultural Research and Development Center.

Contact:

Yebo Li, (330) 263-3855, li.851@osu.edu

On the Web:

Read more about this research. More information about quasar and OARDC’s bioenergy and bioproduct initiatives can be found at quasarenergygroup.com, www.oardc.ohio-state.edu/bioenergy, and bioproducts.osu.edu.