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