Chapter 6 - Oxidative Steam Reforming

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This chapter explores aspects of oxidative steam reforming (OSR) chemistry that are important in a fuel-reforming process. In this method, steam and oxygen are fed together as oxidants to reform the hydrocarbon fuel into a H2-rich fuel stream suitable for fuel cells. OSR is generally considered as a combination of partial oxidation and steam reforming. Feeding air and steam together utilizes the heat generated from exothermic oxidation of the fuel to promote the endothermic steam-reforming reactions. OSR has been an established technology for H2 generation since the late 1950s. It is capable of producing H2 efficiently at high throughputs, which generally makes it the preferred method for industrial use in petrochemical production. However, using OSR for such applications requires a separation plant to remove N2 from air to reduce process gas volumes. Oxygen separation is very capital intensive (almost 40% of total cost) and generally precludes the use of OSR for large-scale applications. However, OSR does have some disadvantages. Using steam requires a water storage and supply system, which adds weight, complexity, and cost to the process. Also, as with any system that uses water, appropriate insulation is needed for applications in colder climates, and added space would be required for a reservoir in an already confined area (assuming for transportation use). Attempts to mitigate storage problems have looked into recycling the fuel cell exhaust to provide the necessary water requirements to maintain reforming capabilities under OSR conditions.