Praveen K. Cheekatamarla

Portable Propane Micro-Tubular SOFC System Development

NanoDynamics Energy Inc. is developing a family of compact, integrated micro-tubular SOFC systems with high volumetric power density and multiple fuel options including methane, propane, diesel and JP8. The development program aims to bring to the market highly efficient, clean, and cost competitive fuel cell systems with outputs above 50We for portable power generation applications. Balance-of-plant (BoP), electronic controls, and power management systems have been identified and integrated with a partial oxidation reformer and SOFC stack. A system test for the integrated process chain was performed with our proprietary cell and system technologies. The performance of a system developed using a micro-tubular SOFC stack is evaluated for different operating conditions. Results from these studies will be presented. System design, integration, and control methodologies are also discussed. Introduction The increase in demand for energy and concern for environmental impacts has created an increase in demand for low-emission energy sources. Fuel cell systems can provide clean energy and with higher efficiency than typical generators (1). To meet increasing power and longevity demands of remote applications, lightweight, man portable fuel cell systems are under development. Balance of Plant (BoP), electronic controls, and power management sub-systems have been designed and tested for use with a micro-tubular solid oxide fuel cell (SOFC) stack and integrated partial oxidation (POX) reformer. This process addressed stack and reformer requirements as well as system level requirements for run-time, fuel type, and typical output loads. Each sub-system was tested under actual conditions to prove functionality, and lastly integrated with the POX reformer and SOFC stack for final evaluation. Proprietary technology allows for subsystem designs that are modular and scalable to meet larger portable power requirements. Sub-System Development Partial Oxidation (POX) Reformer Experiments were conducted to identify and optimize the operating conditions for hydrogen generation via POX reforming of propane fuel using a 2-stage reforming process carried out on proprietary catalyst formulations. ECS Transactions, 7 (1) 483-492 (2007) 10.1149/1.2729127,

Geometric Effects on Tubular Solid Oxide Fuel Cells

Micro-tubular solid oxide fuel cell systems have many desirable characteristics compared with their planar counterparts; however, there are many obstacles and difficulties that must be met to achieve a successful and economically viable manufacturing process and stack design. One of the most important parameters is the cell size and geometries. Anode-supported tubes provide an excellent platform for individual cells. A thin electrolyte layer applied to the outside of the tube helps to minimize polarization losses thus avoiding the difficulty of coating the inside of electrolyte or cathode-supported tubes. The stack design with anode supported tubes also avoids using a fuel chamber on the outside of the tube. Various geometries of the cell support, in terms of diameter, length, cross-section shape and arrangement were investigated. Results of geometric effects on micro-tubular SOFCs will be discussed and presented in this paper.