Biofuels -
August 2008
Interview Date: August 2008
Dr. Gerhard Knothe
From the Special Topic of
Biofuels
According to our Special Topics analysis of biofuels
research over the past decade, the work of Dr. Gerhard Knothe
ranks at #3 by total number of papers, at #11 by total cites,
and at #12 by cites/paper. These rankings are based on 18
qualifying papers cited a total of 229 times.
InEssential
Science IndicatorsSMfrom
Thomson
Reuters, Dr. Knothe's record includes a Highly Cited
Paper in the field of Engineering: "Exhaust emissions of
biodiesel, petrodiesel, neat methyl esters, and alkanes in
a new technology engine," (Knothe G, Sharp CA, Ryan
TW, Energ. Fuel. 20[1]: 403-8, January-February
2006).
Dr. Knothe is a Research Chemist in the Food and Industrial Oil
Research unit of the USDA's National Center for Agricultural Utilization
Research in Peoria, Illinois. In 2006, he received the Industrial Uses of
Soybeans Award from the United Soybean Board and the American Oil Chemists'
Society. He is also a co-editor of The Biodiesel Handbook (AOCS
Press, 2005).
In the interview
below, ScienceWatch.com
talks with Dr. Knothe about his biofuels
research.
Please tell us a little about your research
and educational background.
My research is mainly concerned with the use of vegetable oils and their
derivatives as alternative diesel fuels and related aspects. My educational
background is in chemistry, specifically a Ph.D. in organic polymer
chemistry.
What first interested you in biofuels
research?
"...I would like to see a biodiesel fuel
with optimized properties becoming available or
at least that its realization will be in the near
future."
Prior to joining the National Center for Agricultural Utilization Research,
which at that time was still known as the Northern Regional Research
Center, I had had no professional exposure to biofuels research, except for
having heard about it. I found and still find the perspective of working in
this area intriguing.
Your most-cited original paper in our biofuels
Special Topic is the 2005 Fuel Processing Technology paper,
"Dependence of biodiesel fuel properties on the structure of fatty
acid alkyl esters," (86[10]: 1059-70, 25 June 2005)." Would you sum up
the major points of this paper for our readers?
This paper summarizes and evaluates several important fuel
properties—for example, cetane number, viscosity, and oxidative
stability—that are determined by the major components of biodiesel,
i.e., alkyl esters of fatty acids. By combining insights on the various
properties, it points in a direction for the improvement of biodiesel fuel
properties by modifying the fatty ester composition of biodiesel.
This work has been modified and expanded by a recent publication entitled
"'Designer' biodiesel: Optimizing fatty ester composition to improve fuel
properties," (Energy & Fuels 22[2]: 1358-64, March-April
2008). To summarize the new paper briefly, while methyl oleate overall
possesses good fuel properties, esters of palmitoleic acid or decanoic acid
may be even more preferable for biodiesel.
Another key paper is your 2006 Energy &
Fuels article, "Exhaust emissions of biodiesel, petrodiesel, neat
methyl esters, and alkanes in a new technology engine." Would you talk
a little about the aims, methods, and findings in this
project?
This work had the objective to adapt previous findings on the influence of
various fatty acid chains on exhaust emissions to a newer technology diesel
engine, thus providing additional insights on structure-property
relationships. Ultra-low sulfur diesel (ULSD) fuels had become a salient
issue so it was also straightforward to compare how fatty acid alkyl esters
influence emissions in comparison to straight-chain alkanes, which are
enriched in ULSD and are their "ideal" components. The heavy-duty exhaust
emissions testing was conducted at Southwest Research Institute.
The results showed that biodiesel and its components slightly increased
NOx emissions, as had been known from previous literature, but
reduced particulate matter emissions considerably more than the neat
alkanes, which may favorably affect the exhaust emissions control
technologies needed when using biodiesel as a fuel.
Are there any other papers, regardless of
citations, that you feel are important to your field, and if so, what
are they and why are they important?
"I found and still find the perspective
of working in this area
intriguing."
The perspectives of other researchers and one’s own perspective can
differ significantly on such issues. In any case, I hope that the other
work on fuel properties regarding issues such as cetane numbers, lubricity,
and viscosity, as well as analytical work on methods such as NIR and NMR
are important and interesting.
Where do you see your research going in five to
ten years?
Niels Bohr (and maybe other individuals) has been quoted as saying that
"Prediction is very difficult, especially about the future" and who would
not agree? That aside, I would like to see a biodiesel fuel with optimized
properties becoming available or at least that its realization will be in
the near future. And I hope that the work described in my papers and future
work will eventually help achieve that goal.
What should the "take-away lesson" about your work
be for the general public?
Promising work is ongoing to provide "better" biofuels, in this case
biodiesel.
Gerhard Knothe, Ph.D.
United States Department of Agriculture
Agricultural Research Service
National Center for Agricultural Utilization Research
Peoria, IL, USA
Dr. Gerhard Knothe's current
most-cited paper in Essential Science Indicators,
with 13 cites:
Knothe G, Sharp CA, Ryan TW, "Exhaust emissions of
biodiesel, petrodiesel, neat methyl esters, and alkanes in
a new technology engine," Energ. Fuel. 20(1):
403-8, Jan-Feb 2006. Source:
Essential Science Indicators from
Thomson
Reuters.