Richland (WA) - A new technology enabling the removal of high sulfur content from JP-8 jet fuel is providing an alternative power source to noisy generators.  Enabled by two new technologies developed at the Department of Energy's Pacific Northwest National Laboratory (PNNL), standard fuel cells can now use hydrogen from processed diesel fuel.  A demonstration was shown for three days, powering lights and a commercial refrigeration unit this past Fall.

Alternative power systems are a hot topic right now because they're more efficient.  Fuel cells have the potential to deliver cleaner power through their higher efficiency, but often come at a very expensive price making the tradeoff a significant consideration.  When I interviewed Dr. Jerry Woodall at Purdue University earlier this year, he told me that some highly efficient models, approaching 75% efficiency, were available today.  They cost a few million dollars each and come with operational lifetimes of only a few thousand hours.  He mentioned this in concert to his AlGal material, which is a way to store hydrogen for safe distribution and release as needed.  It is an interesting proposal, but only makes sense if there are higher efficiency fuel cells, or less costly ways of reforming the AlGal.

New technologies
The two new technologies developed involve the removal of sulfur from JP-8 through a fuel desulfurization system, coupled with a fuel reforming system, which basically prepares the fuel for use.  According to the release, "A unique catalytic hydrodesulfurization process developed by PNNL removes sulfur from the JP-8 fuel using syngas as the co-reactant in place of hydrogen.  Gas phase operation of the process allows for a significant increase in throughput and decrease in operating pressure compared with conventional technology.  The process doesn't require consumables or periodic regeneration.  The system was developed with funding from the U.S. Army Tank Automotive Research, Development and Engineering Center."

Once the sulfur has been removed, the fuel acts on the fuel cell like any other fuel source.  Hydrogen and Oxygen are combined across a catalyst, creating electricity in the process.  The fuel cell system itself takes the "clean fuel", which has passed through the desulfurization process, as input.  From there it goes into a fuel processor, which extracts the hydrogen.  That hydrogen is processed through a fuel cell stack with oxygen taken from the air, producing water, heat and electricity in the process.

The benefits of a fuel cell in military applications are primarily from silent operations, though lower emissions and a greater efficiency are also noted.

JP-8 fuel source
JP-8, or "Jet Propulsion 8", is essentially a very clean form of diesel fuel.  It's kerosene based and was originally specified by NATO in 1978.  It's was authorized as a jet fuel source by the U.S. government in 1990, as a replacement for the previous fuel called JP-4.  It includes an icing inhibitor, corrosion inhibitors, lubricants, and antistatic agents.  It is scheduled to remain the de facto jet fuel standard for the military until around 2025.  It is also different from the Jet-A fuel used by commercial aircraft.