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United States Department of Agriculture

Agricultural Research Service

Research Project: ECONOMIC COMPETITIVENESS OF RENEWABLE FUELS DERIVED FROM GRAINS AND RELATED BIOMASS

Location: Sustainable Biofuels and Co-Products

2008 Annual Report


1a.Objectives (from AD-416)
Lower the cost of fuel ethanol production from corn and barley through improved dry grind and dry milling fractionation techniques, including a new 'ammoniation' process. Develop more efficient processes for converting hulled and hulless barley to fuel ethanol and improved, beta-glucan-free, feed coproducts. Through research assist in creation of a new hulless barley-to-ethanol industry in corn deficient regions, particularly the Mid Atlantic States and the North Western U.S. Use the low-starch ('low carb') and high-fiber, high-oil, and high-protein fractions recovered from corn and barley prior to ethanol fermentation to produce health-promoting food ingredients, functional foods, and extruded snacks. Develop improved processes to convert low valued crop-related biomass, byproducts and energy crops being researched in the ARS energy crop program into renewable hydrogen or liquid fuels and conduct economic feasibility studies for integrating this technology into co-located dry grind ethanol plants. Develop small-scale thermo-chemical technologies that economically, efficiently, and sustainably produce hydrogen and coproducts from agricultural materials.


1b.Approach (from AD-416)
Develop a continuous corn ammoniator for improving the conversion of corn to fuel ethanol. Conduct research to develop new dry de-germinators, roller mills, and associated fractionation devices with and without 'ammoniation' as a 'front end' to the traditional dry grind ethanol process. Use these techniques on corn and hulled barley to produce high-starch fractions for more efficient fermentations, and low-starch fractions that can be used as value added health-promoting 'low-carb' food ingredients, healthy edible oils and nutraceuticals. Use newly developed hulless barley cultivars and develop new beta-glucan-degrading enzyme technology to reduce fermentation viscosity and improve the production of ethanol from barley. Prepare hulless barley DDGS from beta-glucanase treated fermentations and examine as high-valued feeds for non-ruminants and aquaculture. Low-valued barley hulls and corn bran from corn and barley ethanol processing and energy crops and residues like switch grass, Eastern gama grass, reed canary grass, alfalfa, and corn stover will be studied as substrates for conversion to hydrogen and related liquid and gaseous fuels by thermochemical processes in a pyrolyzer (pyroprobe) coupled to a gas chromatograph/mass-spectrometer (PY-GC/MS) to analyze gasification products. Promising substrates will be converted in a 2-inch bench-top fluidized-bed reactor to test selected feedstock for yields of H2, syngas, char and pyrolytic oil. Process modeling and economic analysis will be conducted on all the technologies studied, to help direct research toward the most fruitful and commercially feasible areas.


3.Progress Report
We are developing a new consolidated process to convert all the polysaccharides in barley, such as cellulose, hemicellulose, beta-glucans, and starch simultaneously into fermentable sugars, that can then be used in one batch to make fuel ethanol. This process is novel and has the potential to allow future ethanol plants to use a larger range of feedstocks to make ethanol. A provisional patent application has been filed. This research supports ARS NP213 Problem Statement 3a1: Cost-effective conversion of lignocellulosic feedstocks. We are studying the effect of lignin concentration in alfalfa stems to yields of biofuels produced by biochemical and thermochemical processes. We found that the biofuels produced by fermentation is strongly negatively impacted by increasing lignin concentration but the effect was positive for thermal degradation. This research supports ARS NP213 Problem Statement 3b1: Managing biomass feedstocks for thermochemical processing.

We have completed analytical and pilot scale fluidized bed pyrolysis on guayule, a rubber-bearing shrub grown in the Western US from which latex rubber is extracted. Only 10% of the plant is used for latex extraction so the objective is to explore the potential to use the 90% biomass residue (bagasse) for biofuel production. We also upgraded the capabilities of the pilot-scale fluidized-bed pyrolyzer. We then completed pilot-scale production of pyrolysis liquids from the straw of new ARS bioenergy soybean cultivars. This research supports ARS NP 213, Problem Statement 3b3: Commercially viable thermochemical processes for producing liquid fuels. The National Corn Growers Association requested that we do research on the pyrolysis of corn stover and cobs. We completed pilot-scale production of pyrolysis liquids from corn cobs and corn stover using our pyrolysis reactor and did calculations on the composition of the pyrolysis products and the net energy for the process. In response to NCGA and others, we have initiated design sizing for 5, 10 and 100 ton per day pyrolysis systems and have provided this information to stakeholders. This research supports ARS NP 213, Problem Statement 3b3: Commercially viable thermochemical processes. A new continuous liquefaction system was designed and built that could make up to 50% dry solids corn mash. Using this system, continuous fermentation and ethanol stripping of a 40% corn mash was carried out for 60 days. This research supports ARS NP 213 Problem Statement 3a3: New and improved processes for biochemical conversion of starches and sugars to ethanol or butanol. Cost Engineers in our research unit collaborated with EPA researchers to conduct studies on the emissions of greenhouse gases from ethanol production facilities under eight different scenarios. These studies determined that several options resulted in significant reductions in greenhouse gas emissions. These data will be used to support EPA's Rule Making activities related to the Energy Act of 2007. These studies also support Subcomponent 3d: Process Economics and Life Cycle Analyses, Problem Statement 3d1: Estimating process costs and externalized costs in the NP 213 Action Plan.


4.Accomplishments
1. New "EDGE" process makes ethanol from barley better. A new EDGE (Enhanced Dry Grind Enzymatic) process for converting barley to fuel ethanol was developed and optimized. The goal of this project was to develop improved and commercially viable processes to make fuel ethanol from non-food crops outside the Corn Belt. Winter barley is such a crop since it is grown on winter fallow land not used in food production. This project is a cooperative project with Genencor, a Danisco Division. A new company, Osage BioEnergy LLC, is scaling up our lab-scale process at the National Corn to Ethanol Research Center in September 2008 and plans to build multiple ethanol plants on the East Coast using this technology. This research supports the ARS National Program 307/213 Problem Statement 3a3: New and improved processes for biochemical conversion of starches and sugars to ethanol or butanol.

2. Production of Bio-oil from Alfalfa Stems by Fluidized-Bed Fast Pyrolysis – Alfalfa stems are being considered as a potential non-food biomass feedstock for biofuels production. We studied the production of bio-oil (similar to crude oil) from alfalfa stems using a pilot-scale thermal reactor. We successfully produced an energy-dense bio-oil at yields of about 50 wt% of the alfalfa stems that had energy content of about 65% that of conventional diesel fuel. A coproduct was also produced, a very valuable charcoal product with many uses. The alfalfa stem bio-oil production information will be useful for companies interested in building small scale distributed (near the farm) pyrolysis systems, energy crop breeders, extension agents who advice farmer groups, and ultimately the crop producers who are considering use of energy crops as feedstock for liquid fuels via the thermal conversion route. This research supports the ARS National Program 307/213, Problem Statement 3b1: Managing biomass feedstocks for thermochemical processing and Problem Statement 3b3: Commercially viable thermochemical processes for producing liquid fuels from agricultural feedstocks.

3. Making Cellulosic Ethanol from Barley Hulls—Barley hulls can be removed from barley grain prior to making ethanol from the starchy portions of the kernel. Removing this non-fermentable (containing no starch) hull allows more room for fermentable starch in the fermentors of the ethanol plant and improves throughput and economics. New uses must be sought for the hulls, however. We have now developed a process to convert barley hulls into "cellulosic ethanol" through an initial pretreatment, and a new process (simultaneous saccharification and fermentation) that produces ethanol. This additional ethanol would increase a conventional barley ethanol plant's capacity by 6-10% while providing technology the plant could use to convert additional non-food biomass (lignocellulose) like switchgrass into "cellulosic" ethanol. This research supports the ARS National Program 307/213 Problem Statement 3a1: Cost-effective conversion of lignocellulosic feedstocks to ethanol or butanol.

4. Chemical Composition of Bio-oils Produced by Fast Pyrolysis of Two Energy Crops – Energy crops can be heated in the absence of oxygen (a process called pyrolysis) to produce a viscous crude bio-oil. Bio-oil can be further processed into transportation fuels or chemicals. We found that bio-oil we produced from switchgrass had a different chemical composition than that from alfalfa stems. Alfalfa bio-oil had more compounds associated with nitrogen than bio-oil from switchgrass which relates to the protein-rich feedstock. Hence, bio-oil produced from alfalfa is more likely to produce nitrous oxide emissions if burned “as is” than switchgrass bio-oil. This information is useful to energy crop breeders, potential producers and refiners of bio-oil, extension agents who advice farmer groups, and ultimately the crop producer who are considering use of these two energy crops as feedstock for liquid fuels using the thermal conversion route. This research supports the ARS National Program 307/213, Problem Statement 3b1: Managing biomass feedstocks for thermochemical processing and Problem Statement 3b3: Commercially viable thermochemical processes for producing liquid fuels from agricultural feedstocks.

5. An Investigation of the Stability of Functional Lipids in Milled Fractions of Barley and on the Composition of Barley Oil Prepared from Them – Barley oil contains the highest levels of tocotrienols of any natural oil and also significant levels of tocopherols and phytosterols. All these compounds are known to provide health-promoting effects when consumed in human diets. The current study was undertaken to investigate the effect of storage of milled fractions of barley on the composition of these functional lipids in the milled materials and in barley oil prepared from them. Two storage experiments were conducted, one for three weeks at elevated temperature and moisture (35°C and 75% relative humidity) and one for six months under ambient conditions . In summary, both storage conditions caused no change in the amount of extractable oil and in the levels of any of the four tocopherols, but it caused significant degradation of the phytosterols and tocotrienols. These results will help define storage and process conditions that will ensure the production of barley oil with optimal levels of functional lipids. This research supports the ARS National Program 307/213 Problem Statement 3a4: Biorefinery co-products.

6. Economic analysis of distributed processing of biomass to bio-oil for subsequent production of Fischer-Tropsch liquids – A major economic challenge to biomass conversion into renewable fuels is the high cost associated with shipping the biomass due to its low bulk density. We conducted an economic study on using distributed pyrolysis (many small pyrolysis plants spread out over a large area) as a way to produce energy dense bio oil, that can be efficiently shipped to one central refining facility. The economic study showed that distributed processing permits the construction of very large centralized plants that can result in production costs as low as $1.43 per gallon of gasoline equivalent. However, the capital investment for an optimally sized distributed processing system was found to be about twice that of the centralized processing facility. The findings are beneficial to individual farmers, farmers’ cooperatives, and investors interested in biomass refineries because it shows that small scale pyrolysis units, operated by farmers or farmer groups could produce bio-oil as a value added product. This research supports the ARS National Program 307/213, Problem Statement 3b3: Commercially viable thermochemical processes for producing liquid fuels from agricultural feedstocks.


5.Significant Activities that Support Special Target Populations
None


6.Technology Transfer

Number of Active CRADAs1
Number of Invention Disclosures Submitted1
Number of Non-Peer Reviewed Presentations and Proceedings6
Number of Newspaper Articles and Other Presentations for Non-Science Audiences2
Number of Other Technology Transfer6

Review Publications
Boateng, A.A., Mullen, C.A., Goldberg, N.M., Hicks, K.B., Jung, H.G., Lamb, J.F. 2008. Production of bio-oil from alfalfa stems by fluidized-bed fast pyrolysis. Industrial and Engineering Chemistry Research. 47:4115-4122.

Boateng, A.A., Weimer, P.J., Jung, H.G., Lamb, J.F. 2008. Response of thermochemical and biochemical conversion processes to lignin concentration in alfalfa stems. Energy and Fuels. 22:2810-2815.

Banowetz, G.M., Boateng, A.A., Steiner, J.J., Griffith, S.M., Sethi, V., El Nashaar, H. 2008. Assessment of Straw Biomass Feedstock Resources in the Pacific Northwest. Biomass and Bioenergy, 32, 629-634.

Wright, M.M., Brown, R.C., Boateng, A.A. 2008. Distributed processing of biomass to bio-oil for subsequent production of Fischer-Tropsch liquids. Biofuels, Bioproducts, & Biorefining (Biofpr). 2:229-238.

Kim, T., Taylor, F., Hicks, K.B. 2008. Biothanol production from barley hull using SAA (soaking in aqueous ammonia) pretreatment. Bioresource Technology. 99:5694-5702.

Moreau, R.A., Wayns, K., Flores, R.A., Hicks, K.B. 2007. Tocopherols and tocotrienols in barley oil prepared from germ and other fractions from scarification and sieving of hulless barley. Cereal Chemistry. 84(6):587-592.

Flores, R.A., Hicks, K.B., Wilson, J. 2007. Surface abrasion of hulled and hulless barley: Physical characterization of the milled fractions. Cereal Chemistry. 84(5):485-491.

Boateng, A.A. 2007. Characterization and Thermal Conversion of Charcoal Derived from Fluidized-Bed Fast Pyrolysis Oil Production of Switchgrass. Industrial and Engineering Chemistry Research. 46:8857-8862.

Sohn, M., Himmelsbach, D.S., Barton Ii, F.E., Griffey, C.A., Brooks, W., Hicks, K.B. 2007. Near-Infrared analysis of ground barley for use as a feedstock for fuel ethanol production. Journal of Applied Spectroscopy. 61 (11). p. 1178-1183.

Sohn, M., Himmelsbach, D.S., Barton Ii, F.E., Griffey, C.A., Brooks, W., Hicks, K.B. 2008. Near-infrared analysis of whole kernel barley: comparison of three spectrometers. Applied Spectroscopy. 62(4). p. 427-432 2008.

Mullen, C.A., Boateng, A.A. 2008. Chemical composition of bio-oils produced by fast pyrolysis of two energy crops. Energy and Fuels. 22:2104-2109.

Last Modified: 7/31/2014
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