Jun
29
Washington State University researchers used the ethanol and water mixture and a small amount of electricity in a novel conversion system to produce pure compressed hydrogen. The researcher’s press release claims the new efficient way to produce hydrogen gas from ethanol and water has the potential to make clean hydrogen fuel a more viable alternative for gasoline to power cars.
Electrochemical reforming to produce hydrogen gas and capture CO2 in-situ. Image Credit: Washington State University. Click the research paper link below for more information.
The innovation means that hydrogen could be made on-site at fueling stations, so only the ethanol solution would have to be transported. It is a major step in eliminating the need to transport high-pressure hydrogen gas, which has been a major stumbling block for its use as a clean energy fuel.
The team’s paper has been published on the journal Applied Catalysts A: General.
Su Ha, professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering and corresponding author on the paper said, “This is a new way of thinking about how to produce hydrogen gas. If there are enough resources, I think it has a really good chance of making a big impact on the hydrogen economy in the near future.”
Using hydrogen as a fuel for cars is a promising but unrealized clean energy. Like an electric-powered car, a hydrogen fuel-cell powered car doesn’t emit any harmful carbon dioxide. Unlike an electric car, it can be filled up with hydrogen gas in minutes at hydrogen fueling stations.
Despite the promise of hydrogen technology, however, storing and transporting high-pressure hydrogen gas in fuel tanks creates significant economic and safety challenges. Because of the challenges, there is little hydrogen gas infrastructure in the U.S., and the technology’s market penetration is very low.
In their work, the WSU researchers created a conversion system with an anode and a cathode. When they put a small amount of electricity into the ethanol and water mixture with a catalyst, they were able to electrochemically produce pure compressed hydrogen. Carbon dioxide from the reaction is captured in a liquid form.
Instead of having to transport hazardous hydrogen gas, the conversion method would mean that the existing infrastructure for transporting ethanol could be used and that the compressed hydrogen gas could be easily and safely created on-demand at gas stations.
Ha explained, “We’re already using ethanol-containing gasoline at every gas station. You can imagine that an ethanol water mixture can be easily delivered to a local gas station using our existing infrastructure, and then using our technology, you can produce hydrogen that is ready to pump into a hydrogen fuel cell car. We don’t need to worry about hydrogen storage or transportation at all.”
The electrochemical system the team developed uses less than half the electricity of pure water splitting, another method that researchers have studied for de-carbonized hydrogen production. Instead of working hard to compress the hydrogen gas later in the process, the researchers used less energy by instead compressing the liquid ethanol mixture, thereby directly producing an already compressed hydrogen gas.
Graduate student Wei-Jyun Wang, a co-lead author on the paper, noted, “The presence of the ethanol in water changes the chemistry. We can actually do our reaction at a much lower electrical voltage than is typically needed for pure water electrolysis.”
Their system also doesn’t require an expensive membrane that other water splitting methods do. The resulting hydrogen from the electrochemical reaction is then ready for use.
Jamie Kee, a Voiland School postdoctoral researcher and one of lead authors on the paper explained, “A process that offers a low-electrical energy cost alternative to water electrolysis and can effectively capture carbon dioxide while producing compressed hydrogen could have a significant impact on the hydrogen economy. It’s really exciting because there are a whole lot of aspects that play into improving the production methods of hydrogen.”
The researchers are working to scale up the technology and operate it in a continuous manner. They also are working to make use of the carbon dioxide captured in the liquid.
The team’s work was funded by the Gas Technology Institute and the US Department of Energy’s RAPID Manufacturing Institute.
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From an outside view this technology has great potential. There are a few matters that beg questions though. First, where is the oxygen that had to be released when the hydrogen was formed? If its coming out as O2 – just giving it back to the atmosphere sounds fine or feed it back to the fuel cell. Then, in view that most all ethanol is formed from biological materials, why not just give the CO2 food source back to the plant kingdom for reuse once released from the electrolyte solution?
The big question remains though, could the technology be scaled to operate in a vehicle? The idea of an interstate traffic jam packed with hydrogen fueled vehicles – a single system failure could be a very horrific disaster. The team’s system on each vehicle would bring the risks much closer to ethanol ignition properties vs. hydrogen and might, if the water to ethanol proportion is helpful, reduce the risks, perhaps to lower than gasoline.
The last big question is how much current is needed? Would today’s car start battery suffice to get things going until the fuel cell takes over?
The potential of this work is spectacular. A water ethanol mix could very well expand the four season range of electrically powered vehicles due to a lower freezing temperature of the mixture.
This team’s insight and innovation deserves more than just congratulations. Press releases seldom reveal everything everyone wants to know, but from what has been revealed, your humble writer is very impressed, indeed.
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