Hydrogen reformer — Optional equipment for your next car?
Rather than building a new infrastructure of hydrogen fueling stations, researchers are looking at ways to reform gasoline onboard vehicles. One way is steam reforming, in which hydrocarbon fuel reacts with steam at high temperatures over a catalyst. Hydrogen atoms are stripped from water and hydrocarbon molecules to produce hydrogen gas. Problem is, the car must sit 15 min before being driven: It takes a while for steam reformer prototypes to reach the right temperature to begin producing hydrogen.
The DOE wants to speed things up and so set a goal of 30 sec for cold start time with an intermediate target of 60 sec by the end of this year. PNNL researchers developed a compact steam reformer, which can produce large amounts of hydrogen-rich gas from a liquid fuel in only 12 sec. Microchannels, narrower than a paper clip, deliver high rates of heat and mass transport within the reactor. This hastens reactions and shrinks down the reactor. For example, a complete microchannel fuel processor for a 50-kW fuel cell is expected to occupy less than 1 cu ft. “The key feature of the new design is that the reforming reactor and water vaporizer are configured as thin panels with hot gases flowing through the large surface area of the panel,” says Greg Whyatt, lead project engineer.
PNNL researchers are currently working to reduce fuel consumption and airflow required during startup. Also, integration with other components is necessary to demonstrate a complete fuel processor system that starts up in less than 30 sec.