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Dairy effluent modeled as viable feedstock for renewable diesel

DRI energy research team apply conceptual model to illustrate higher biofuel yield

RENO - Production of fuels and chemicals from sustainable biomass feedstocks is crucial in addressing the increasing global energy demands and growing concerns of greenhouse gas emissions and related adverse climate impacts from the use of fossil fuels.

New research published in the Journals of Biotechnology for Biofuels and Bioresource Technology by renewable energy researchers at Nevada’s Desert Research Institute, in partnership with Utah State University, has illustrated the feasibility of using dairy industry effluent products to grow yeast, which is an excellent feedstock for producing renewable diesel fuel. Dr. Umakenta JenaDr. Umakanta Jena displays DRI’s unique HTL biomass reactor used to produce energy-dense liquid bio-crude. Utilizing the unique research laboratories on DRI’s Reno campus, scientists produced an energy-dense liquid-fuel precursor (known as “bio-oil” or “biocrude”) through a wet biomass conversion method known as hydrothermal liquefaction (HTL). This resulting bio-crude is compatible with existing refinery technology and can be processed into advanced biofuels which could supplement traditional petroleum-based gasoline or diesel fuels.

HTL presents a promising alternative to traditional bio-fuel production because of its ability to convert wet biomass into biocrude during a single step process conducted in hot, compressed water. HTL has typically been applied to algae feedstocks, but relatively little research has been done using yeasts that are grown on byproducts from the production of milk and dairy processing.

"The novelty of our study lies in the co-solvent we applied to reduce the pressure, temperature, and time of the HTL process," explained the study’s lead author Umakanta Jena, Ph.D., an assistant research professor of bioenergy and renewable energy in DRI’s Clean Technologies and Renewable Energy Center (CTREC). "Using isopropanol as co-solvent we were able to obtain significantly higher bio-crude yields from the HTL process."

The study also integrated baseline HTL experimental data with a techno-economic analysis (TEA), led by Dr. Jason C. Quinn from Utah State University, to understand the potential of incorporating the HTL process into the dairy industry and on the economic viability of large-scale production of renewable diesel fuel.

"Although technological demonstration of HTL capabilities has been established, minimal work has been performed to understand the economic and environmental feasibility of implementing this technology into an industrial application," said S. Kent Hoekman, co-author on the study and director of DRI’s Clean Technologies and Renewable Energy Center. "Further, no previous work has investigated the environmental impacts of generating renewable diesel from yeast fermented on delac and subsequently converted to biocrude using the HTL process."

While additional research is needed before commercial or public applications are ready for market, suggested use of waste agriculture streams in bio-fuel production can increase the productivity and sustainability of rural agricultural areas, while also providing a new biofuel industry feedstock that has significant advantages compared to traditional feedstocks.

The mission of CTREC is to promote and coordinate renewable energy research development, demonstration, and deployment activities at DRI. For more information on the services and capabilities of DRI's Clean Technology and Renewable Energy Center (CTREC) please visit - www.dri.edu/ctrec

PUBLICATIONS:

Journal of Biotechnology for Biofuels: 
http://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-015-0345-5

Journal of Bioresource Technology:
http://www.sciencedirect.com/science/article/pii/S0960852415010391

About the Desert Research Institute: DRI, the nonprofit research campus of the Nevada System of Higher Education, strives to be the world leader in environmental sciences through the application of knowledge and technologies to improve people’s lives throughout Nevada and the world.