Hydrogen Made From Ethanol With 90% Efficiency Using Inexpensive Catalyst
by Matthew McDermott, Brooklyn, NY on 08.21.08
image: Wikipedia
A few weeks ago MIT announced that one of its researchers had made a major breakthrough in the production of hydrogen at room temperature using a cobalt and phosphorus catalyst.
Now comes word that researchers at Ohio State University have made another interesting discovery: A new way to produce hydrogen from biofuels using an inexpensive catalyst. It’s not exactly at room temperature—the process runs at 660 degrees Fahrenheit (350°C)—but the cerium oxide catalyst costs about $9 a kilogram and makes hydrogen from ethanol with 90% efficiency.
How Does it Work?
According to OSU the process works like this:
The process starts with a liquid biofuel such as ethanol, which is heated and pumped into a reactor, where the catalyst spurs a series of chemical reactions that ultimately convert the liquid to a hydrogen-rich gas.At the end of the process, waste gases such as carbon monoxide, carbon dioxide and methane are removed, and the hydrogen is purified. To make the process more energy-efficient, heat exchangers capture waste heat and put that energy back into the reactor. Methane recovered in the process can be used to supply part of the energy.
Distributed Production for Hydrogen
Umit Ozkan, professor of chemical and biomolecular engineering at OSU believes that this research offers a solution to the nagging problem of transporting hydrogen as well. She believes that by using this method a distributed production strategy could develop.
Instead of making hydrogen from biofuel at a centralized facility and transporting it to gas stations, we could use our catalyst inside reactors that are actually located at the gas stations. So we wouldn’t have to transport or store the hydrogen—we could store the biofuel and make hydrogen on the spot.
Though ethanol has been the only biofuel used in this process so far, Ozkan’s team is investigating how to apply this process to other liquid biofuels as well.
The Hydrogen Economy
“Major Breakthrough” in Hydrogen Production: Video Interview with Daniel Nocera
New Record Set for Storing Hydrogen in Material for Fuel Cells
Honda Shows Off FCZ Fuel Cell Concept Car
Thirsty for more? Check out these related articles:
- I Don’t Think Alternative Energy Means What You Think It Means: Fred Pearce to BP
- US Farmer’s Incomes Now Tied More to Ethanol Than Food, Economist Says
- Cambodia’s First Ethanol Plant Will Use One-Fifth of Nation's Cassava Crop
- 36 Gallons of Water Per Mile: Corn Ethanol Uses More Water Than Any Other Biofuel
High Oil Prices Help Revive US Steel Industry, Create American Jobs
|
The TH Interview: News Corp.'s Carbon Neutral Empire (Part 2)
|
Why wouldn't we just burn the ethanol?
Because the ethanol still produces harmful emissions upon combustion. Hydrogen burns clean, or better still put it through a fuel cell for electric cars for more efficiency.
I think running hydrogen through a fuel cell may give greater tank-to-wheel efficiency than burning ethanol.
Why wouldn't we just autoreform and existing hydrocarbon in an SOFC?
File this one under "cool but not really useful"
Just speculation, of course, but if you burn ethanol in an ICE, you create carbon dioxide/monoxide (from incomplete combustion) which is then released to the atmosphere.
If you burn hydrogen/use it in a fuel cell, the only emission is water vapour, and the carbon dioxide/monoxide byproducts from the catalytic reaction can be more easily sequestered/fed to algae to repeat the process,since it's done on an industrial scale, rather than a car-by-car scale.
Myself, I don't know why they don't just build massive electrolysis plants powered by photovoltaics... there's nothing wrong with electrolysis as a source of hydrogen if you have enough energy.
@Garret: Because you can use the hydrogen in a fuel cell which is far more efficient than burning the ethanol. Whenever you burn a fuel, you inevitably lose energy with all that lost heat. In fact, in most internal combustion engines, you actually use more energy to cool the engine further reducing the efficiency.
But my comment is, what happens with all of the CO and CO2 byproducts? How much is it? And can you just pump it into a greenhouse to get rid of it?
Good news otherwise tho.
Burning ethanol in an ICE isn't a terribly efficient process. A fuel cell is 2 to 3 times as efficient and have a hard time running on things other than pure hydrogen. Plus, burning ethanol, while cleaner than gasoline, still creates alot of CO2, while hydrogen fuel cells produce water only.
Stradic is right, and to address your question, there are many ways to sequester CO and CO2 with more efficient methods currently under development.
I'd appreciate any definitive answer on this, but in addition to what stradric says, I would think one advantage would be that it centralizes the other 'waste gasses' for use in growing other biofuels like algae (that could be a source for this hydrogen?) , rather than spewing them out on the road. This, I would think, would help prevent the air quality problems associated with using ethanol as a fuel source.
Piston engines are very poor on combustion, because the fuel is ignited with an electrical spark. Sandia labs already did test igniting with light.
I suggest you take a quick look at this:
http://uk.youtube.com/watch?v=Sf3M-_RUSCM
http://uk.youtube.com/watch?v=m9YTNN_ntFU
Hot lasers used to be expensive items back when Sandia did their tests. But today they are a dime a dozen in all CD burners.
We could ignite fuel mixtures with light, instead of spark plugs, which would dramatically improve combustion.
The best part about this technology is that we can produce ethanol domestically and are continually finding increasingly efficient means of doing so.