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Technology Stocks : Ballard Power -world leader zero-emission PEM fuel cells -- Ignore unavailable to you. Want to Upgrade?

To: Bart Goemaere who wrote (4220)	5/31/1999 8:21:00 AM
From: Rickmas	Read Replies (2) \| Respond to of 5827

Carbon Dioxide Poisoning Bart, on this page zevco.com Zevco says "Alkaline fuel cells benefit from oxygen enriched air, free from carbon dioxide." This is a nice way of saying alkaline fuel cells stop working in air containing small amounts of carbon dioxide. "The electrolyte in this fuel cell is concentrated (85 wt%) KOH in fuel cells operated at high temperature (~250°C), or less concentrated (35-50 wt%) KOH for lower temperature (<120°C) operation. The electrolyte is retained in a matrix (usually asbestos), and a wide range of electrocatalysts can be used (e.g., Ni, Ag, metal oxides, spinels, and noble metals). The fuel supply is limited to non-reactive constituents except for hydrogen. CO is a poison, and CO2 will react with the KOH to form K2CO3, thus altering the electrolyte. Even the small amount of CO2 in air must be considered with the alkaline cell." Fuel Cell Handbook ch2bc.org This may be why they are focusing on marine applications. Urban environments are rich in CO and CO2, while marine environments should be much better for AFCs. Yes, I know about the ZEVCO Taxi. I do not know how well it is holding up. I must admit that I was surprised to learn it used AFCs. I'm not discounting the technology, although it has been pushed aside in favor of the other fuel cell types by the majority of participants. It works very well in the absence of CO2 and has been used extensively and successfully in the past in controlled environments such as the space program. Perhaps a simple filter is all it needs to compete with PEM FCs on planet Earth. -- Rickmas