Exploring the catalytic deoxygenation of bio liquids to form liquid hydrocarbons
24 October 2010
Researchers from Tuskegee University, the Air Force Research Laboratory, Applied Research Associates and Florida State University report on efforts to develop an efficient method of removing oxygen from liquid biomass to produce petroleum-comparative liquid hydrocarbons using hydrogen and a NiMo/γ-Al2O3 catalyst in a paper in press in the journal Renewable Resources.
Although bio-based resources such as waste biomass, vegetable oils and animal fats are considered as promising sources for delivering large quantities of non-petroleum liquid fuels, the abundance of oxygen in the form of various aliphatic and aromatic oxygenates decreases the quality of the resulting biofuels. A key step in some production pathways, therefore, has to be the reduction of oxygen content (deoxygenation).
Various catalysts in addition to NiMo/γ-Al2O3 and CoMo/γ-Al2O3 are well known for deoxygenating liquid biomass; however, these catalysts are formulated and tested mostly for refining and hydro-cracking petroleum products. Research is needed in the development of dual function catalysts suitable for both deoxygenizing and isomerizing functions.
—Kwon et al.
Kwon et al. report on their efforts on deoxygenating liquid biomass (methyl laurate—a fatty acid methyl ester—and canola oil) with hydrogen and a NiMo/γ-Al2O3 catalyst in terms of various oxygen removal conditions such as reaction temperature and pressure, catalyst amount, and hydrodynamics of heterogeneous reaction mixture in the batch reactor.
Methyl laurate. Methyl laurate was converted mainly to undecane (liquid alkane hydrocarbon C11H24) and dodecane (liquid alkane hydrocarbon C12H26) in the presence of hydrogen and the catalyst. Lauric acid is formed as a major intermediate product.
Formation of the two primary hydrocarbon products and CH4 increased with increased catalyst amount, increased H2 pressure, and increased reaction temperature over the range of 300-350 °C. Formation decreased with higher temperatures.
Canola oil. Canola oil is converted mainly into heptadecane (C17H36) and octadecane (C18H38) in the presence of hydrogen and the catalyst. Heptadecanic acid is formed as a major intermediate product.
Formation of heptadecane, octadecane, and heptadecanic acid increased with catalyst amount, reaction temperature, and H2 pressure. Elevated hydrogen pressures and prolonged reaction durations were required in the presence of a catalyst to increase conversion of canola oil to hydrocarbons such as heptadecane and octadecane.
Resources
Kyung C. Kwon, Howard Mayfield, Ted Marolla, c, Bob Nichols and Mike Mashburn (2010) Catalytic deoxygenation of liquid biomass for hydrocarbon fuels. Renewable Energy In press doi: 10.1016/j.renene.2010.09.004
Is the removal of the two oxygen atoms from the ester in biodiesel really worth the extra work. Is there that much of an energy increase with the alkane vs the ester?
Posted by: Coke Machine | 25 October 2010 at 06:15 AM
It's not the energy increase, it's the change in physical properties such as cloud point.
Posted by: Engineer-Poet | 25 October 2010 at 09:41 AM