2006 Outstanding Master's Thesis - David Vernon

Understanding the Affects of Reactor Geometry and Scaling through Temperature Profiles in Steam-Reforming Hydrogen Production Reactors

Dissertation / Thesis Directed By: Professor, Paul Erickson, Mechanical and Aeronautical Engineering Department

Abstract

Hydrogen can be produced by a variety of methods including steam-reformation of hydrocarbon fuels. In past studies the quasi non-dimensional space velocity parameter (inverse residence time) has been shown to be insufficient in accurately predicting fuel conversion in hydrocarbon-steam reformation. Heat transfer limitations have been manifest with reactors of different geometries for different scale applications. The proper understanding of scaling effects is important for design of small scale reformer systems that would be used in distributed stationary and on-board vehicle applications. In order to achieve optimal fuel conversion, the heat transfer limitations and the changes of these limitations with respect to geometry and scale must be considered in the reactor design. In this investigation measurement devices and techniques are developed in order to acquire accurate temperature profiles from reactors of different aspect ratios operating at the same space velocity. These data allow preliminary quantification of heat transfer limitations in relation to reactor geometry in steam reformation. Using both the temperature profile information as well as the traditional space velocity limitations proper scaling of steam reformers may be accomplished. Furthermore knowledge of the temperature profile during operation at both low and high space velocities (flow rates) may allow control of future reactor designs with reduced IO count reducing both cost and complexity.