Saturday, March 21, 2009

Hydrogen from gasoline: ExxonMobil TV commercial

After seeing the new ExxonMobil TV commercial about the company's technology that produces hydrogen from gasoline on board a vehicle, I got curious. How exactly does one derive hydrogen from gasoline in a moving car?

First, some context. Hydrogen is the essential fuel for fuel cells. But our hydrogen infrastructure is in its infancy. The difficulties of supplying and storing hydrogen in cars have hindered widespread adoption of fuel cells in automobiles.

At the same time, we have a mature distribution system for gasoline, and storing the stuff in cars is no sweat. What better solution to fuel-cell power woes than converting gas to hydrogen while it's inside a car?

I dug around a bit, and learned that the technology for extracting hydrogen from gasoline and other hydrocarbons has been around for a few years. The gasoline is made to react with steam at high temperatures in the presence of a catalyst, and that liberates hydrogen from the gas and the water. There's a little more to it -- the hydrogen then has to be separated from other gases before being fed to the fuel cell -- but that's the basic scenario.

To commercialize the technology, ExxonMobil has partnered with 3 other companies and Ben Gurion University of the Negev (Israel). They plan to test their new hydrogen production system in forklifts, and eventually roll it out to passenger vehicles.

If the plan works, fuel-cell-powered cars will be as common as, well, gasoline-powered cars today.

Alternative-energy purists may carp that this technology still requires use of fossil fuels. They may want to look at the bright side.

If converting gasoline to hydrogen improves fuel economy by 80%, as the TV commercial claims, then that means we need to use only one-fifth as much gas as we do now. Not a bad trade-off for putting more fuel-cell cars on the roads more rapidly.

One question remains, though. After the hydrogen is stripped from the hydrocarbon, what happens to the carbon?

1 comment:

Rob said...

Where does the carbon go? Good question indeed.

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