Jet-fueled electricity at room temperature: New fuel cell can run without high heat

November 5, 2014
Shelley Minteer -- a University of Utah professor of materials science and engineering, and also chemistry -- has developed a fuel cell that can covert jet fuel to electricity at room temperature without igniting the fuel, thanks to the use of enzymes as catalysts in the reaction. The new fuel cells can be used to power portable electronics, off-grid power and sensors. Credit: Dan Hixson, University of Utah

University of Utah engineers developed the first room-temperature fuel cell that uses enzymes to help jet fuel produce electricity without needing to ignite the fuel. These new fuel cells can be used to power portable electronics, off-grid power and sensors.

A study of the new cells appears online today in the American Chemical Society journal ACS Catalysis.

Fuel cells convert energy into electricity through a chemical reaction between a fuel and an oxygen-rich source such as air. If a continuous flow of fuel is provided, a fuel cell can generate electricity cleanly and cheaply. While batteries are used commonly to electric cars and generators, fuel cells also now serve as power generators in some buildings, or to power fuel-cell vehicles such as prototype hydrogen-powered cars.

"The major advance in this research is the ability to use Jet Propellant-8 directly in a fuel cell without having to remove sulfur impurities or operate at very high temperature," says the study's senior author, Shelley Minteer, a University of Utah professor of materials science and engineering, and also chemistry. "This work shows that JP-8 and probably others can be used as fuels for low-temperature fuel cells with the right catalysts." Catalysts are chemicals that speed reactions between other chemicals.

In the new study, the University of Utah team investigated Jet Propellant-8 or JP-8, a kerosene-based that is used by the U.S. military in extreme conditions such as scorching deserts or subzero temperatures.

Converting this jet fuel into electricity is difficult using standard techniques because jet fuel contains sulfur, which can impair metal catalysts used to oxidize fuel in traditional fuel cells. The conversion process is also inefficient, with only 30 percent of the fuel converted to electricity under the best conditions.

To overcome these constraints, the Utah researchers used JP-8 in an enzymatic fuel cell, which uses JP-8 for fuel and enzymes as catalysts. Enzymes are proteins that can act as catalysts by speeding up chemical reactions. These fuel cells can operate at room temperature and can tolerate sulfur.

An enzyme "cascade" of two enzymes – alkane monooxygenase and alcohol oxidase – was used to catalyze JP-8. Hexane and octane, which are chemically similar to JP-8, also were tested as fuels. The researchers found that adding sulfur to their enzymatic fuel cell did not reduce power production.

"Enzymatic fuel cells are a newer type of fuel cell, so they are not currently on the market," says Minteer, also a professor with USTAR, the Utah Science Technology and Research economic development initiative. "However, researchers haven't been able to use JP-8 before, because they haven't had the enzymes to be able to oxidize JP-8."

Solid-oxide cells at temperatures above 950 degrees Fahrenheit have made use of JP-8, but this is the first demonstration at room temperature, Minteer says. Now that the team has shown the enzyme catalysts works, they will focus on designing the and improving its efficiency, she adds.

Explore further: Researchers develop fuel cells for increased airplane efficiency

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30 comments

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tscati
2 / 5 (3) Nov 05, 2014
Interesting, but at the end of the day it's just a low-temperature way of turning fossil hydrocarbons into CO2 and energy, no?
Eikka
4.8 / 5 (6) Nov 05, 2014
Interesting, but at the end of the day it's just a low-temperature way of turning fossil hydrocarbons into CO2 and energy, no?


JP-8 is very similiar to trans-esterized vegetable oil.
jkbgbr
3.8 / 5 (4) Nov 05, 2014
no heat emission means no waste heat, thus the overall efficiency may be higher than that of internal combustion engines
Eikka
5 / 5 (6) Nov 05, 2014
no heat emission means no waste heat, thus the overall efficiency may be higher than that of internal combustion engines


Low operating temperature doesn't imply no waste heat. Just lower temperature waste heat, which unfortunately means it's more difficult to reclaim for other uses. The device can't be 100% efficient.

Enzymatic action implies the reactor works below 75 C and probably below 50 C which would mean that any waste heat would be directly usable for space heating, but not for hot water or any industrial applications.
FredZ
3 / 5 (2) Nov 05, 2014
The noble dream of Pons and Fleischmann has finally come true!
krundoloss
4 / 5 (3) Nov 05, 2014
Low operating temperature doesn't imply no waste heat. Just lower temperature waste heat, which unfortunately means it's more difficult to reclaim for other uses.


OMG, They are generating electricity directly from fuel with no waste heat, and you are pointing out that there is no waste heat to collect? Are you just used to the idea of wasting energy and don't want to change?

This is great, any better way to produce energy without all the fuss and bother of internal combustion is awesome. This tech seems stable, maybe even safer also.
jscroft
5 / 5 (4) Nov 05, 2014
This sounds like a very big deal. i wonder about power output.
bearly
5 / 5 (2) Nov 05, 2014
I want a portable unit to mount on my RV so that I can have electricity in the woods.
Modernmystic
3.7 / 5 (3) Nov 05, 2014
What's the energy density though? It obviously isn't the same as it is if you just burn it. I love that they're doing this research. It's EXACTLY what's needed, but why do an article on it and not put out the most critical piece of information??
gkam
1 / 5 (5) Nov 05, 2014
I think our Blackbirds (A-12, YF-12A, and SR-71s), at Edwards ran on JP-8. If no significant cost reductions have taken place, you cannot afford it for power generation.
gkam
1 / 5 (5) Nov 05, 2014
The important point here is the use of enzymes which allows the use of the particular fuel.
gkam
1 / 5 (5) Nov 05, 2014
"What's the energy density though? It obviously isn't the same as it is if you just burn it"
-----------------------------------------
Yes. The energy density of the fuel is the energy density of the fuel. I think you are talking about output, W/M2, or something. It is the use of terms only.

Watts per square meter of the surface area pf the membrane will be lower, and so will the significant losses from thermal extremes. Lower temperature means significantly more efficiency in this case. Not true in IC engines.
gkam
1 / 5 (5) Nov 05, 2014
Energy density of the producing surface is not very important, because they are stacked together like plates in a battery. The low temperature operation and good efficiency allow versatile operation. I expected us to have replaced local neighborhood transformers (the big ones), with fuel cells running on Methane. That way, the neighborhoods can all be power-sufficient on their own, but linked together for dependability.
jscroft
not rated yet Nov 05, 2014
Ultimately it's going to come down to two macro metrics: power/weight and cost/kwh.
Captain Stumpy
5 / 5 (3) Nov 05, 2014
I think our Blackbirds (A-12, YF-12A, and SR-71s), at Edwards ran on JP-8. If no significant cost reductions have taken place, you cannot afford it for power generation.
@gkam
with modification it might have? IDK
normally the Blackbird would burn somewhat conventional JP-7 ( it was difficult to light, though)
so to start the engines, triethylborane (TEB), which ignites on contact with air, was injected to produce temperatures high enough to ignite the JP-7

you sometimes saw this on ignition as a green flame

AFAIK it remained the fuel of choice as far up as 1992
gkam
1.7 / 5 (6) Nov 05, 2014
I used to hear and watch the Blackbirds start up, back when they still used the Buick Wildcat engines. It sounded like a drag race.
tekram
not rated yet Nov 05, 2014
http://pubs.acs.o...s500802d

Bioelectrocatalytic Oxidation of Alkanes in a JP-8 Enzymatic Biofuel Cell
Yevgenia Ulyanova †, Mary A. Arugula ‡, Michelle Rasmussen ‡, Erica Pinchon †, Ulf Lindstrom †, Sameer Singhal *†, and Shelley D. Minteer *‡
Eikka
4.8 / 5 (6) Nov 05, 2014
OMG, They are generating electricity directly from fuel with no waste heat


Again: this device is NOT 100% efficient. There IS waste heat.

and you are pointing out that there is no waste heat to collect? Are you just used to the idea of wasting energy and don't want to change?


I'm pointing out that the waste heat comes out at a lower temperature, which makes it more difficult to make use of.
Modernmystic
not rated yet Nov 05, 2014
http://pubs.acs.o...s500802d

Bioelectrocatalytic Oxidation of Alkanes in a JP-8 Enzymatic Biofuel Cell
Yevgenia Ulyanova †, Mary A. Arugula ‡, Michelle Rasmussen ‡, Erica Pinchon †, Ulf Lindstrom †, Sameer Singhal *†, and Shelley D. Minteer *‡


So if I'm doing the conversions correctly this about doubles the density of the best batteries and puts it on par with gunpowder and just below TNT.
Thank you sir!
Eikka
5 / 5 (3) Nov 05, 2014
I expected us to have replaced local neighborhood transformers (the big ones), with fuel cells running on Methane. That way, the neighborhoods can all be power-sufficient on their own, but linked together for dependability.


A good idea in principle, but fuel cell catalysts and the cells themselves wear out in use, making the electricity substantially expensive because you need to keep rebuilding it.

Fuel cells are about equal to large diesel engines both in efficiency and longevity, except they cost more to build. Wartsila sells 10-100 MW diesel engines that operate at over 50% efficiency.

Fuel cells, and large diesels for that matter, are currently only used for load matching - especially in conjunction with wind power - because fast adjusting power bought from the spot market can easily cost the utility a hundred times more than baseload power. That justifies the otherwise steep price of these technologies.

Eikka
5 / 5 (5) Nov 05, 2014


So if I'm doing the conversions correctly this about doubles the density of the best batteries and puts it on par with gunpowder and just below TNT.
Thank you sir!


Which numbers? The article is behind a paywall and the only visible figure is for power density, which is not the same thing as energy density.
Modernmystic
not rated yet Nov 05, 2014


So if I'm doing the conversions correctly this about doubles the density of the best batteries and puts it on par with gunpowder and just below TNT.
Thank you sir!


Which numbers? The article is behind a paywall and the only visible figure is for power density, which is not the same thing as energy density.


Ach, missed it. I'll keep googlin.
gkam
1 / 5 (5) Nov 05, 2014
"Fuel cells, and large diesels for that matter, are currently only used for load matching - especially in conjunction with wind power "

Where is that? We used all types, from phosphoric acid to solid oxide in the late 1970's to the late 1980's when I left PG&E, but none were sufficiently practical. There are many places for them, but not grid power quite yet.
Modernmystic
not rated yet Nov 05, 2014
Virtually all load matching done for a wind farm is done either with hydrocarbons or nuclear, which means when you build a wind farm you're really building a power station that's 30% wind and 70% something else because that's about how often the wind blows on a good site.
gkam
1 / 5 (5) Nov 05, 2014
With all that, wind still produced more new capacity than any other technology last year. Gosh, I guess they don't know it is all a trick.
rocket77777
not rated yet Nov 05, 2014
It is slightly odd since ethanol based cell phone fuel cell from few years ago should been room temperature too. If this thing can be made efficient, it can be used in home, car and portable usb charger.
Eikka
5 / 5 (4) Nov 05, 2014
Where is that? We used all types, from phosphoric acid to solid oxide in the late 1970's to the late 1980's when I left PG&E, but none were sufficiently practical. There are many places for them, but not grid power quite yet.


Well, google says Wartsila recently sold a 50 MW gas powered engine system to Hawaii for load balancing needs, and a 7 unit 140 MW facility to Mexico. Apparently they've sold over 7000 MW worth of diesel and gas engines for grid balancing applications in North America, and why not - the engine can be started and stopped in minutes without the need to spool a gas turbine up or down.

They're using these: http://www.indust...sg-.html

As for the fuel cells, I don't know of any commercial unit that wasn't some sort of pilot plant or prototype. They're still too expensive for mainstream production.
Eikka
5 / 5 (4) Nov 05, 2014
With all that, wind still produced more new capacity than any other technology last year. Gosh, I guess they don't know it is all a trick.


They do know it's a trick, but they don't care because the government promises them money for it anyways. That's the only reason the turbines are standing in the first place.

Barely anybody who works with large scale wind power today, at least on the administrative level, can ignore the fact that the output is really patchy and unreliable, and generally unimpressive on the system scale, but that doesn't really matter as long as you get paid.

The rest are mostly starry-eyed dreamers with no touch of reality, or wishful thinkers who hope and believe the solutions are just around the corner.
krundoloss
5 / 5 (1) Nov 06, 2014
I'm pointing out that the waste heat comes out at a lower temperature, which makes it more difficult to make use of.


That's fine and all, its just that waste heat is the enemy of efficiency, I never expected someone to desire to have waste heat, much less worry about how to collect it, since the collection of the waste heat and converting to energy has low efficiency, so therefore the most efficient use of energy is by not generating waste heat in the first place.
Eikka
4.3 / 5 (6) Nov 07, 2014
I never expected someone to desire to have waste heat, much less worry about how to collect it


Nobody desires waste heat.

The point was that it's not necessarily a good thing to have a low-temperature fuel cell over a high temperature fuel cell, because with a high temperature fuel cell it's easier to collect the waste for other useful purposes. If you can't avoid waste heat, it's better that it comes out at high temperature than low temperature.

It's also more difficult to get the waste heat out of a low temperature fuel cell, because the small temperature gradient restricts heat flow. That means the power density of the cell can't be very high, or it will overheat itself kinda like an engine with no radiator.

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