Researchers produce hydrogen quickly and cheaply using plant waste
Hydrogen is the ideal gas for use in low-emissions combustion engine or fuel cell-powered vehicles, due to its almost non-existent greenhouse gas emissions. Production costs, however, are higher compared to gasoline and around 95 percent of it is currently produced, somewhat counter-intuitively, from fossil fuels. Now researchers at Virginia Tech claim to have created a method to produce hydrogen fuel using a biological technique that is not only cheaper and faster, but also produces hydrogen of a much higher quality ... and all from the leftover stalks, cobs, and husks of corn.
The waste products of corn – stover, as it is called – is the basis for the Virginia tech hydrogen production, where the researchers used an enzymatic process to break the stover down into hydrogen and carbon dioxide. Specifically, the team partly utilized the results of previous investigations it performed with cellulose to glucose conversion to help create a system that is claimed to produce hydrogen levels previously thought only theoretically possible.
To do this, Joe Rollin, a doctoral student in the Department of Biological Systems Engineering at Virginia Tech, used a specifically tailored set of genetic algorithms to help assess each part of the enzymatic process that turns corn stover into hydrogen and carbon dioxide. Rollin also proved the capacity of this method to enable both of the sugars found in plant material – glucose and xylose – simultaneously, thereby detailing a method of accelerating the speed at which the hydrogen could be produced.
This detailed research proved a breakthrough for the team when creating the practical model, as biological conversions can normally only use these two types of sugar one at a time, whereas the new system uses them both at once.
As a result, the newly incorporated process model is claimed to triple reaction rates whilst also reducing the size of the processing plant required to do so. This means that the predicted size for a production facility using the new process should be around the size of a standard gas station, which the team also asserts will save money on capital costs.
"This means we have demonstrated the most important step toward a hydrogen economy – producing distributed and affordable green hydrogen from local biomass resources," said Percival Zhang, a professor in the Department of Biological Systems Engineering, Virginia Tech.
The practical upshot of this research, according to the scientists, will be the ability to one day efficiently produce hydrogen affordably, with a high product yield and superior reaction rates. By taking advantage of the artificial enzymatic pathways the team has developed, it is hoped that increasing the ordinary limit of hydrogen-producing microorganisms (which is also at least 10 times faster than the most efficient photo-hydrogen production system) and avoiding complex sugar flux regulation problems, that hydrogen production could easily be achieved in a nationwide network of self-sufficient hydrogen-fueling stations.
The hydrogen produced in this way is also said to be so pure that it will be a perfect candidate for use in hydrogen fuel cells, such as those used in upcoming hydrogen fuel cell vehicles like Toyota's FCV.
"We believe this exciting technology has the potential to enable the widespread use of hydrogen fuel cell vehicles around the world and displace fossil fuels," said Rollin.
Funded in part by the Shell GameChanger initiative and the National Science Foundation’s Small Business Technology Transfer program, the process is now part of a commercial enterprise called Cell-free Bioinnovations recently formed by Rollins and Zhang.
The results of this research were recently published in the journal the Proceedings of the National Academy of Sciences
Source: Virginia Tech
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The public would be well served to remember that our civilization did run on biofuels some centuries ago. In those days it was called burning wood, riding horses, and plowing with oxen. We have since abandoned the model, precisely because it was severely limited in available energy output.
We can improve on that by research, but there are fundamental thermodynamic limits on the energy conversion efficiency of biological systems. Those limits are far below other methods of harnessing solar energy. A good example is the comparison between biofuels (e.g. from the best crop we have - sugarcane) and PV-electrolysis, where the former has a ~0.5% efficiency of solar to fuel conversion, and the latter about 10% (solar to hydrogen). It would be completely self-deceiving to think that anything we do with algae or any other biological system can improve the conversion efficiency by 20000% - and that would be just to catch up with electrolysis. Other methods have the potential to convert sunshine to hydrogen at >30%, roughly an order of magnitude more than what one can even theoretically achieve via photosynthesis.
Thermally breaking water is a better solution to hydrogen production. At a few thousand degrees (~2500C) the hydrogen/oxygen bonds in water break. This is easily achieved with a nuclear heat source. Thorium reactors could meet the portable hydrogen demand easily and thorium is sufficiently plentiful to meet that need for the next several hundred thousand years. As an added benefit radioactive waste can produce hydrogen from water directly as well. It is impossible to render hydrogen radioactive so the hydrogen would be clean and usable. This would mean that the minimal waste produced by the thorium reactors (Something like 1/100th that of a traditional reactors)
It looks like there is an electrolysis method that uses dry steam and electricity applied without collection plates at high temperatures that can electrolyze water, but it generally requires a nuclear reactor to heat the water to steam and power the electricity for the reaction so why not just thermally separate the water? (http://www.acs.org/content/acs/en/pressroom/newsreleases/2012/march/nuclear-power-plants-can-produce-hydrogen-to-fuel-the-hydrogen-economy.html)
For those who are so scared of the word "nuclear" they can't be bothered to research thorium and understand its safety and lack of waste products there have been efforts to use concentrated solar to perform thermal separation, but I think they had issues with scaling and oxidization as well as the issue of requiring insanely huge swaths of permanently sunny land. So you are trading a minimal nuclear waste stream for permanent destruction of delicate habitats like deserts.
Isn't CO2 something we want less of?
Isn't CO2 something we want less of?
No,you are just returning CO2 recently sequestered by the plant waste to the atmosphere,which is why the process is called carbon neutral.Burning fossil fuel, in contrast, releases millions of tons worth of stored CO2 in a matter of decades.
But one company could make a profitable venture based upon this technology, if the claimed efficiency is achieved. Notably, vast amounts of plant waste is now hauled away as garbage. Usually, this biomass garbage is a nuisance. The owner of the garbage must spend time or money to get rid of it. So a new company could obtain the biomass for free (or be paid to haul it away.)
Similar methods have been attempted by Verenium Inc (now a division of BP). They have constructed a plant adjacent to a ethanol production plant that converts sugarcane sugar into ethanol. The sugarcane factuality had been hauling away the bagasse (cellulosic parts of the sugarcane plant). Now Fuel Cell Inc using its cellulose-digesting enzymes to convert the bagasse into ethanol. This method is more cost efficient only because the costs of acquiring the raw material have been eliminated and shipping costs for moving the raw material. And it keeps this biomass out of landfills (which are rapidly filling up.)
The cost effectiveness derives from minimizes costs throughout the entire process of acquiring the biomass to production of fuel (hydrogen, methanol, or ethanol.) Similar plants have been constructed near timber mills to render sawdust and wood chips into ethanol. More at: http://www.biofuelsdigest.com/bdigest/2012/08/17/why-sugarcane-bagasse-is-the-most-promising-pathway-for-cellulosic-ethanol/
Or search for 'verenium ethanol cellulosic ethanol'
Wonder if charged anode and cathode might polarize the molecules in different flow directions, and prevent recombination? Just thinking out loud.
Now, if instead of the enzyme producing hydrogen and carbon dioxide - a distinct drawback in its own right - it could be persuaded to produce hydrogen and carbon MONoxide - AKA syngas - which could be used as feedstock for the good old Fischer-Tropsch process, then we would be cooking with gas!