[The Montana Professor 25.1, Fall 2014 <http://mtprof.msun.edu>]

Developing A Conversion Process Technology to Produce the Next Generation Fuels and Chemicals from Natural Oils

Randy Maglinao, PhD
Research Associate, Bio Energy Center, MSU-Northern

Md. Joynal Abedin, PhD
Senior Research Scientist, Bio Energy Center, MSU-Northern


There is overwhelming consensus among climate scientists that the climate change we are now experiencing is very likely due to the emission of greenhouse gases mainly caused by human activities. Greenhouse gases like carbon dioxide, methane, and nitrogen oxides tend to accumulate in our atmosphere and cause global changes like unusual weather patterns and increasing average global temperatures. The leading source of greenhouse gases is the increasing use of fossil fuels. Although it is not feasible to stop using fossil fuel totally—as it is our major energy source to power our homes and transportation industry—it is very possible to find alternative ways to reduce its use.

In the transportation industry, one way of reducing the consumption of fossil fuels is to make their use more efficient. An example is the use of appropriately designed engines, such as a hybrid of internal-combustion and electric engine systems. Hybrid engine systems work well with light vehicles and buses. At low average speeds and the frequent stop-and-go operations common to city driving, hybrid engine systems are most efficient. However, for heavy trucks and aviation, these systems may work as inefficiently as internal combustion engines due to long periods of operation and the heavy loads associated with their use. In the aviation industry, it will take years to gather enough information on how hybrid engines work in extreme flight conditions. Moreover, regulatory agencies will not allow these types of engines in commercial planes unless they are certified as safe and dependable. Nobody wants to experience engine failure while travelling 30,000 feet above the ground. For this type of transportation, the use of alternative and biomass-based fuels is an option with significant potential. First and second generation biofuels such as biodiesel are proven and well-established. However, they have their share of deficiencies due to differences in chemical composition as compared to fossil-based fuels. Biodiesel, in particular, has different fuel performance properties than fossil-based jet fuels, making biodiesel incompatible with most aviation engines. While it is not impossible to develop and certify new aviation engines that can make use of first generation biofuels, it is impractical at the moment and will take decades to achieve a level of usefulness worthy of certification. The most convincing alternative is to develop a biofuel that has chemical composition similar to fossil-based fuels, i.e., containing only hydrocarbons. These types of biofuel are referred to as next generation or "drop-in" biofuels. Since most of the biomass sources—sugars, natural oils, and lignocellulosic materials—are made up of oxygenated compounds, the challenge is to develop a conversion technology that both removes oxygen molecules from the feedstock and produces suitable fuels.

There are several conversion pathways that have been studied to produce next generation biofuels, such as Alcohol to Jet (ATJ) by alcohol oligomerization, Pyrolysis to Jet (PTJ) by hydrotreating of pyrolysis oils, and Hydrotreated Depolymerized Cellulosic Jet (HDCJ) by catalytically depolymerizing cellulose to hydrocarbons. To date, only hydroprocessed esters and fatty acids jet fuel (HEFA-jet) produced from hydrotreating of natural oils such as jatropha, algae, and camelina oil has been certified by the American Society for Testing and Materials (ASTM) under the D7566 specification, "Aviation Turbine Fuel Containing Synthesized Hydrocarbons." The Synthetic Paraffinic Kerosene (SPK) through Fischer-Tropsch process has also been certified by ASTM but cannot be considered a biofuel as it is produced from syngas derived from coal and natural gas.

While HEFA-jet contains only hydrocarbons with carbon chain lengths comparable to conventional jet fuel, it is still not completely similar to fossil-based jet fuels. HEFA-jet lacks the aromatic content associated with fossil-based jet fuels. This lack of aromatic content affects properties such as fuel density (Moses, 2007; Rahmes et al., 2009). Material compatibility with old gaskets and seal systems could be also an issue for biofuels with no aromatics (Moses, 2007). To mitigate some of the anticipated operational problems associated with the use of these bio-jet fuels, a maximum blend of 50% with conventional jet fuel is allowed. Moreover, HEFA-jet is produced under an energy-intensive process requiring relatively higher temperatures and greater pressures to achieve a reasonable conversion. Renewable diesel or green diesel which is produced from hydrotreating of natural oils contains hydrocarbons with longer carbon chain length (16 to 22 carbons) than HEFA-jet. Nestle Oil and Honeywell UOP are examples of refining companies that uses hydrotreating technology to produce renewable diesel. Like HEFA-jet, renewable diesel is produced under higher temperatures and pressures.

Montana State University-Northern's Bio-Energy Center is engaged in developing and deploying novel conversion processes to produce next generation biofuels. One of the Center's current research projects, reported on here, is the conversion of camelina oil to advanced transportation fuels and chemicals. Unlike HEFA-jet and renewable diesel, the process under study uses green chemistry to minimize the production of unwanted by-products and avoid the use of high temperatures and pressure.

Aviation industry and biofuels

Road transportation fuel like gasoline and diesel is less critical in its fuel quality and performance properties than jet fuel. A diesel truck stalled in the road due to a clogged fuel filter is forgivable; jet fuel frozen in flight is not. This is the reason why a lot of time and effort is being expended in researching, developing, testing, and certifying next generation bio-jet fuels. For example, it took more than five years of testing and development before SPK and HEFA received certification from ASTM.

aviation fuel consumption
Figure 1. US aviation annual fuel consumption, 1991-2011. [Notes: • aviation fuel usage; Δ annual percent change. Source: Davis et al., 2013.]

The development and certification of next generation bio-jet fuels is in line with a growing aviation industry. The industry has expanded significantly, both in global traffic and fuel usage, over the period 2000-2005 (Lee, et al, 2009). In the United States, despite the world-changing events in the early 2000s and the global financial crisis of 2007-2008, fuel usage in the aviation industry has shown a generally increasing trend (Figure 1). In 2011, the U.S. air industry consumed about a million barrels per day of petroleum (Davis et al, 2013). This is 3% of the total carbon emissions from all end-use sectors, excluding military operations. Carbon dioxide and nitrogen oxides (NOx) are the major greenhouse gas emissions from aircraft operations. Other emissions include water vapor, CO, hydrocarbons, SOx, sulfate particles, and soot. The utilization of domestic bio-jet fuel at 20% of the U.S. current consumption would reduce the country's petroleum usage by about 2.3 billion gallons annually. Government and private sectors have identified a unified research and development roadmap to assist in accelerating the development and deployment of bio-jet fuels. The U.S. Department of Agriculture, National Business Aviation Association, and U.S. Department of Transportation have teamed up to re-launch the "Farm to Fly" initiative with the primary objective of developing and advancing a comprehensive sustainable aviation biofuel rural development plan (National Business Aviation Association, 2013). With almost exactly the same goals, the European Commission, Airbus, and representatives from aviation and biofuels producing industries launched the "European Advanced Biofuels Flightpath" during the early quarter of 2011 (European Commission, 2014). This initiative targets the deployment of two million tons per year of renewable aviation fuels by 2020.

The technology

Back in 2011, Soriano et al. developed a low energy chemical process that converts camelina oil and other natural oils to hydrocarbons with carbon chain lengths similar to jet fuel. The process utilizes proprietary procedures and techniques to produce a biofuel that contains not only straight-chain hydrocarbons but also aromatic and cyclic hydrocarbons. Figure 2 illustrates the schematic flow diagram of the process. The first step involves a well-established alkene metathesis reaction—the rearrangement of alkene fragments at carbon-carbon double bonds using a metal-based catalyst (Grubbs, 2007; Vougioukalakis and Grubbs, 2009). This first step produces the necessary precursors (mostly in the form of alkenes) needed to produce paraffinic, aromatic, and cyclic hydrocarbons.

MSUN bioenergy process
Figure 2. Schematic flow diagram of the process developed at MSU-Northern Bio-Energy Center.

The next step is the proprietary aromatization, cyclization, and hydrogenation of the product following metathesis. Most transportation fuels contain mostly alkanes, also called saturated hydrocarbons. Though the hydrotreating process which produces HEFA-jet is able to make hydrocarbons, this high temperature process only produces paraffinic hydrocarbons. Rahmes and his co-workers (2009) reported that HEFA-jet fuels produced from camelina, jatropha, and algae do not contain any aromatics. The drawback of having no aromatics in the fuel is a density lower than the minimum limit of 0.775 kg/L at 15°C (ASTM D1655, 2013; Rahmes et al, 2009). Unlike HEFA, the aromatization and cyclization step in the process is able to produce both cyclic and aromatic hydrocarbons. Gas chromatography-mass spectrometry results confirm the presence of aromatics and cyclic compounds in the fuel fraction of the product. Depending on the operating conditions, up to 25% by weight of aromatics can be produced. Currently, the Bio-Energy Center is improving the process to produce bicyclic hydrocarbons as well. Bicyclic hydrocarbons could also increase the density of the fuel, as do aromatics. Thus, having bicyclic hydrocarbons and aromatics in the fuel may allow for higher blend levels of bio-jet and fossil-based fuels.

Camelina as feedstock

While the process developed at the MSU-Northern Bio-Energy Center is applicable to most types of natural oils, our research focuses on utilizing oil produced from Camelina sativa, an emerging high-value crop in Montana and Northern Great Plains. Camelina is relatively easy to grow and is considered a low input crop. It requires low seeding rate, is competitive in terms of weed control, and adapts well to dry and marginal lands (Ehrensing and Guy, 2008; Pilgeram, 2007). The ability of camelina to grow in situations not suitable for food production minimizes the food-versus-fuel concerns typically encountered in energy crop development. In addition, camelina's tolerance for the northern midwest's drought and spring freezing climate makes it an ideal oilseed crop for Montana. Field trial results in Havre showed an average yield of 1,666 lb/acre (McVay and Lamb, 2008). Camelina can also be used as a rotational crop for wheat. Fallow and rotation cropping systems are favored by dry-land framers since they contribute to restoring soil moisture and nutrients and breaking pest cycles.

Camelina-derived biofuel has been shown to reduce greenhouse gas emissions. In a recent Federal Register issued by the U.S. Environmental Protection Agency (EPA), biodiesel, renewable diesel, and jet fuel derived from camelina qualified as biomass-based diesel and advanced biofuels under the Renewable Fuels Standard 2 ruling (EPA, 2012). This suggests that EPA has estimated a 50% or more reduction in GHG emissions associated with transportation fuels derived from camelina. As an example, HEFA-jet derived from camelina reduces greenhouse gas emissions by 75% compared to conventional fossil based-jet fuel (Shonnard et al., 2010). With the unique characteristics and properties of camelina, it is the ideal feedstock in Montana for producing next generation biofuels.

Looking to the future

Like every technology developed in the laboratory, the production of jet fuel from camelina needs to be scaled up for commercial production. There is still much work to be done before this technology is used for large-scale purposes. There is still a lack of engineering data to take the process beyond the laboratory scale. The lack of an inexpensive, efficient, and robust heterogeneous metathesis catalyst needs to be addressed. This is why the Bio-Energy Center is working hard to produce this data and address the challenges at hand in order to succeed in the commercialization of the technology. Currently, the Center is developing a new heterogeneous catalyst for the process as well as optimizing the process for large-scale production. The Center is also in collaboration with private industry, including the world's largest aircraft manufacturer, toward achieving this goal.


ASTM D1655-13a. 2013. Standard Specification for Aviation Turbine Fuels. American Society for Testing and Material International.

Davis, S.C., Diegel, S.W., Boundy, R.G. 2013. Transportation Energy Data Book: Edition 32. U.S. Department of Energy. [Accessed on July 10, 2014]. Available at http://cta.ornl.gov/data/index.shtml

Ehrensing, D.T., Guy, S.O. 2008. Camelina. OSU Extension Service, Oregon State University. Jan 2008, Oilseed crops series EM8953-E.

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McVay, K.A., Lamb, P.F. 2013. Camelina Production in Montana. A Self-Learning Resource from Montana State University Extension. March, 2008. [Accessed on May 3, 2013]. Available at http://store.msuextension.org/publications/AgandNaturalResources/MT200701AG.pdf

Moses, C.A. 2007. Development of the Protocol for Acceptance of Synthetic Fuels under Commercial Specification. CRC Contract No. AV-2-04.

National Business Aviation Association. 2013. NBAA Joins in Launching 'Farm to Fly' 2.0. 2013 Press Releases. [Accessed on July 10, 2014]. Available at http://www.nbaa.org/news/pr/2013/20130418-034.php

Pilgeram, A.L., Sands, D.C., Boss, D., Dale, N., Wichman, D., Lamb, P., Lu, C., Barrows, R., Kirkpatrick, M., Thompson, B., Johnson, D.L. 2007. Camelina Sativa, A Montana Omega-3 and Fuel Crop. Alexandria, VA: ASHS Press.

Rahmes et al., 2009. Sustainable Bio-derived Synthetic Paraffinic Kerosene (Bio-SPK) Jet Fuel Flights and Engine Tests Program Results. 9th AIAA Aviation Technology, Integration, and Operations Conference. American Institute of Aeronautics and Astronauts, Inc. AIAA 7002.

Environmental Protection Agency, 2012. Regulation of Fuels and Fuel Additives: Identification of Additional Qualifying Renewable Fuel Pathways Under the Renewable Fuel Standard Program. In Vol 77, No.3, 2012; 40 CFR part 80.

Soriano, N., Maglinao, R., Narani, A. 2012. Process of Converting Natural Plant Oils to Biofuels. Provisional Patent 61/599,745.

Shonnard, D.R., Williams, L., Kalnes, T.N. 2010. Camelina-derived jet fuel and diesel: Sustainable advanced biofuels. Environmental Progress & Sustainable Energy, 29 (3), 382-392.

Vougioukalakis, G.C., Grubbs, R.H. 2009. Ruthenium-Based Heterocyclic Carbene-Coordinated Olefin Metathesis Catalysts. Chemical reviews, 110 (3), 1746-1787.

[The Montana Professor 25.1, Fall 2014 <http://mtprof.msun.edu>]

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