Diver heating using hydrogen catalytic reactions

A simple hydrogen catalytic combustion heater for divers is described consisting of a canister filled with a chemical catalyst including precious metals such as platinum or palladium deposited on a support matrix of porous carbon particles. A small percentage of hydrogen is injected into an oxygen-rich (nitrox or heliox) gas mixture prior to passing it through the catalyst bed. As the gas mixture flows through the canister the catalyst facilitates the reaction of hydrogen with a small amount of oxygen to produce water vapor and approximately 104,000 Btu´s (110,000 kJ) of heat. This approach was recently tested to produce a closed, or semi-closed heating cycle to provide a hot water heating circuit to be used with thermal protection garments for divers. Preliminary analysis has shown that over 2 kilowatts of heat can be produced, sufficient heat to sustain up to 6 divers in 32°F water, with only 25 standard cubic feet of hydrogen per hour. This paper describes the operation of this hydrogen catalytic water heater and these recent laboratory tests