Six commercially available materials have been tested as granular sorbents to be used in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (1073 to 1153 K) flue gas of pressurized fluidized-bed combustors (PFBC) for proposed combined-cycle power generation. Tests were performed using a simulated dry flue gas of PFBC in a laboratory-scale, fixed-bed combustor. Diatomaceous earth and activated bauxite were found to be the two most promising sorbents. The experimental results of screening tests are presented, along with the effects of temperature and superficial velocity and space velocity of the flue gas on the sorption performance for the two sorbents. Possible sorption mechanisms, applications of the sorbents and preliminary cost evaluations are discussed.

Gaseous alkali metal compounds transported form a pressurized fluidized-bed coal combustor (PFBC) to a gas turbine might cause hot corrosion of turbine hardware. Activated bauxite was found to be a very effective granular sorbent for use in granular-bed filters for removing gaseous alkali metal compounds from simulated hot flue gas of PFBC. Also, activated bauxite was demonstrated to be easily and effectively regenerated for reuse by a simple water-leaching process. Experimental results are presented for cyclic experiments showing the regenerability of water-leaching of activated bauxite on which NaCl vapor or KCl vapor was sorbed. Observed physical changes and particle attrition of activated bauxite as a result of regeneration are discussed. The sorption mechanisms of the regenerated activated bauxite are related to the chemical compositions of the leachate.

The Department of Energy's Office of Advanced Automotive Technologies has been supporting the development of fuel-flexible fuel processors at Argonne National Laboratory. These fuel processors will enable fuel cell vehicles to operate on fuels available through the existing infrastructure. The constraints of on-board space and weight require that these fuel processors be designed to be compact and lightweight, while meeting the performance targets for efficiency and gas quality needed for the fuel cell. This paper discusses the performance of a prototype fuel processor t hat has been designed and fabricated to operate with liquid fuels, such as gasoline, ethanol, methanol, etc. Rated for a capacity of 10 kWe (one-fifth of that needed for a car), the prototype fuel processor integrates the unit operations (vaporization, heat exchange, etc.) and processes (reforming, water-gas shift, preferential oxidation reactions, etc.) necessary to produce the hydrogen-rich gas (reformate) that will fuel the polymer electrolyte fuel cell stacks. The fuel processor work is being complemented by analytical and fundamental research. With the ultimate objective of meeting on-board fuel processor goals, these studies include: modeling fuel cell systems to identify design and operating features; evaluating alternative fuel processing options; and developing appropriate catalysts and materials. Issues and outstanding challenges that need to be overcome in order to develop practical, on-board devices are discussed.