VOLUME 13, NO. 1 DEC 1999
Bringing the dream of automotive fuel cells closer to reality
Chemical Engineering Department Head Ravindra Datta, left, and doctoral student Faisal Syed are part of a team working on a fuel cell system for automobiles that promises to double fuel efficiency and reduce air pollution.
Today's cars are running on empty. Fossil fuels are a major source of pollution and the world's oil supplies may be depleted within 50 years at the current rate of consumption. At the same time, the number of cars is expected to double worldwide in the next two decades.
Ensuring that the rubber continues to meet the road may take a miracle. Ravindra Datta, head of WPI's Chemical Engineering Department, and other researchers working in the field have found it: a car that practically runs on water. Actually, the car that Datta envisions runs on electricity produced in a fuel cell stack, which combines hydrogen fuel and oxygen from the air and produces pure water as its only "waste." This radically new technology, now adopted in concept by all automakers, promises to double the fuel efficiency of cars while dramatically reducing air pollution.
Datta is working with doctoral candidate Tony Thampan and postdoctoral researchers Hao Tang and Ilie Fishtik to help make this dream a reality. They note that fuel cells have been around for many years and are routinely used in spacecraft, where their fuel is generally pure hydrogen. But developing more down-to-earth applications will require that fuel cells be built that can be powered by conventional liquid fuels, which are cheaper and safer. In addition, the cells that power tomorrow's cars will have to produce electricity at a fraction of the cost of the units that power spacecraft.
Datta says that with the help of a catalyst, it is possible to convert gasoline to hydrogen in a fuel cell system, though the oxygen is not pure enough and contains amounts of carbon monoxide that, while well below acceptable emissions levels, are high enough to poison the fuel cell. This is just one of the significant roadblocks that Datta and his team must help overcome before cars powered by fuel cells can take to the road.
In one such project, Fishtik and Datta have devised a catalytic process that readily converts watery ethanol into a hydrogen stream that is suitable for use in a fuel cell. The process is efficient and clean, and works at the relatively moderate temperature of 500°C. "Ethanol is renewable, it is less toxic and hazardous than gasoline, and does not contain the catalyst poisons present in fossil fuels," Datta says. "The other advantage is that you don't need fuel-grade pure ethanol, which requires substantial energy to produce. In fact, 80-proof whiskey makes a fine fuel."
In another project funded by the Navy through H Power Corp., Thampan, Hao and Datta are working on developing fuel cells that are more tolerant of carbon monoxide. The researchers are designing anode electrocatalysts that are not readily poisoned by carbon monoxide, as well as polymer electrolyte membranes that can work at higher temperatures, where carbon monoxide is less troublesome, and at lower relative humidities, which avoids the problem of electrode flooding.
"We are one of the few university groups doing research on both fuel cells and the reformer technologies," Datta notes. "We are not trying to develop a car. We break down the barriers related to the proposed use of fuel cells in automobiles into problems that can be worked on by our researchers and graduate students. Our approaches are based on first developing a fundamental understanding of these problems, and then trying to fix some of them."
This type of research, he believes, will ultimately lead to a fuel-cell car that is a viable and affordable consumer product. "When that happens," he says, "WPI will have been part of the solution of an important problem with worldwide implications."
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