2003-01-1366 Performance of Microlith Based Catalytic Reactors for an Isooctane Reforming System Marco Castaldi, Maxim Lyubovsky, Rene LaPierre, William C. Pfefferle and Subir Roychoudhury Precision Combustion, Inc. Copyright © 2003 SAE International ABSTRACT Use of catalytically coated short contact time (SCT) design approaches for application in mass transfer controlled reactors such as Auto Thermal Reformers (ATR’s) is an area of much recent interest. Precision Combustion, Inc. (PCI) has developed an efficient and compact ATR using ultra-short channel length, high cell density SCT substrates (Microlith ® ). PCI has also extended this Microlith technology to other fuel processor reactors that operate at lower temperatures and are not mass transfer limited. Namely, reactors for the Water Gas Shift (WGS) and Preferential Oxidation (PROX) of CO have been developed. Due to the higher surface area per unit volume of the Microlith substrate compared to conventional monoliths, size advantages have been observed for these reactions, which are more kinetically controlled. This results not only in shortened startup times and quick load following capability but also allows much smaller and lighter reactors – required attributes for automotive fuel cell applications. In this paper, experimental data on the performance of Microlith based ATR, WGSR and PROX reactors for reforming isooctane is presented. Transient and durability characteristics have also been included and compared to Department of Energy (DOE) targets. INTRODUCTION One of the major obstacles in widespread use of fuel cells is the lack of a hydrogen supply infrastructure, which is constrained by significant technical and economic hurdles. On-board or localized reforming of liquid fuels, such as gasoline, which have extensive supply networks, is a sensible approach until a hydrogen supply infrastructure is available. To realize this goal there have been a number of attempts to develop on- board fuel processors. Although significant progress continues to be made, major remaining hurdles need to be overcome before on-board fuel processing technology can be successfully implemented. Current fuel processors are limited by low power density, sluggish transient response and slow startup time mostly as a consequence of large size and weight. The required size and weight goals for a practical system have been outlined in the DOE PNGV targets. Short Contact Time (SCT) reactor design approaches offer the potential for development of advanced fuel processors with a high likelihood of overcoming these barriers. Precision Combustion, Inc. (PCI), using a SCT Microlith technology has developed extremely compact, lightweight and efficient fuel processor reactors – Auto Thermal Reformers (ATR), Water Gas Shift Reactors (WGSR) and Preferential Oxidation Reactors (PROX) – with very fast transient response capability. While These reactors have been demonstrated over a range of conditions and fuels. In this paper we report the performance of these reactors under conditions suggesting consecutive operation, i.e. same H 2 O/C and O 2 /C ratio with the objective of demonstrating feasibility of a compact and fast transient response integrated reformer system. SHORT CONTACT TIME APPROACH Short contact time approach to chemical reactor design essentially consists of passing a reactant mixture over a catalyst at very high flow velocities, such that the residence time of the gas mixture inside the catalyst bed is on the order of milliseconds). Such SCT processes have commercially been used for a long time, for example in ammonia oxidation reaction in nitric acid production, where a mixture of ammonia and air is passed over precious metal gauzes. Near 100% conversion of ammonia with very high selectivity to the desired product is achieved. PCI has been developing application of similar catalytic systems based upon wire mesh coated with precious metal catalysts for many applications [1]. In more recent years Prof. Lanny Schmidt has proposed application of this system to a range of partial oxidation reactions by using either monolith supported catalysts [2] or a single gauze of bulk precious metal catalyst [3]. A research group at Shell performed similar partial oxidation over catalyst coated on a foam substrate with high porosity and tortuosity [4]. Using coated metal screen catalytic systems (Microlith) we have designed reactors operating at very high gas hourly space velocities for both mass transfer