(631b) Catalyst Stability for Sulfuric Acid Decomposition as Influenced by Platinum Group Metal Composition and Reaction Pressure
AIChE Annual Meeting
2009
2009 Annual Meeting
Hydrogen Production for a Hydrogen Economy
Reaction and Separations for Thermochemical Cycles
Thursday, November 12, 2009 - 3:40pm to 4:05pm
Thermochemical cycles produce hydrogen through a series of chemical reactions where the net result is the production of hydrogen and oxygen from water at much lower temperatures than from direct thermal decomposition. All chemicals within the cycle are recycled and the heat to drive the reactions, which tend to be endothermic, must be provided by a primary energy source. When the primary energy driver is nuclear or solar heat, hydrogen can be generated without producing greenhouse gasses, and can provide independence from our dwindling supplies of fossil fuels.
Among the high number of thermochemical water-splitting cycles proposed in the literature, the sulfur based cycles, including the Sulfur-Iodine (S-I) and the hybrid sulfur (HyS) cycles have generated considerable interest. The sulfur cycles all employ a high temperature catalytic sulfuric acid decomposition reaction to produce oxygen and generate SO2 for recycle. Platinum supported on porous titanium oxide has been shown to be very active over a wide range of temperatures; however, the catalytic metal deactivates too rapidly, primarily due to sintering in the oxidizing environment.
This paper will focus on the addition of high melting point platinum group metals to the platinum catalyst as an option to reduce deactivation. In addition, the affect of elevated pressure (up to 30 bar) on catalyst stability will be presented.