Suthida Authayanun

A review of the development of high temperature proton exchange membrane fuel cells

Abstract Due to the need for clean energy, the development of an efficient fuel cell technology for electricity generation has received considerable attention. Much of the current research efforts have investigated the materials for and process development of fuel cells, including the optimization and simplification of the fuel cell components, and the modeling of the fuel cell systems to reduce their cost and improve their performance, durability and reliability to enable them to compete with the conventional combustion engine. A high temperature proton exchange membrane fuel cell (HT-PEMFC) is an interesting alternative to conventional PEMFCs as it is able to mitigate CO poisoning and water management problems. Although the HT-PEMFC has many attractive features, it also possesses many limitations and presents several challenges to its widespread commercialization. In this review, the trends of HT-PEMFC research and development with respect to electrochemistry, membrane, modeling, fuel options, and system design were presented.

Performance Analysis of a Biomass Supercritical Water Gasification Process under Energy Self-sufficient Condition

Abstract Depletion of fossil fuel and environmental concerns stimulate the use of clean and renewable energy. Biomass is regarded as a potential energy source and can be efficiently converted to a useful synthesis gas via incomplete combustion in a gasification process. However, the thermal gasification causes a tar formation and requires high energy input when wet biomass is used. The objective of this study is to investigate the performance of an autothermal biomass gasification process in supercritical water. A flowsheet model of the gasification process is developed and validated with experimental data. Thermodynamic analysis is performed based on the minimization of total Gibbs free energy. Simulations are performed to study effects of key operational parameters on the supercritical water gasification process at an energy self-sufficient condition, which a total net heat energy can be zero. Hydrogen in the synthesis gas product and thermal efficiency of the gasification process are also considered and suitable operating conditions of the autothermal biomass gasification for hydrogen production are identified.

Effect of Flow Pattern on Single and Multi-stage High Temperature Proton Exchange Membrane Fuel Cell Stack Performance

A high-temperature proton exchange membrane fuel cell (HT-PEMFC) is a promising clean and effective technology for power generation because of its simplified water and heat management as well as high CO tolerance. Therefore, it could be possible to directly use a reformate gas for HT-PEMFC without the need for sophisticated purification processes. Due to the non-uniform of H2 and CO distributions within fuel cells, the stack design is one of the key factors to enhance the performance and efficiency of HT-PEMFC. In this study, a single HT-PEMFC stack is investigated by considering the CO poisoning effect. The mathematical model of HT-PEMFC based on the electrochemical reaction model coupled with the diffusion model of a gas diffusion layer and electrolyte film layer is used for simulation studies. At high fuel utilization, hydrogen is highly consumed and CO concentration increases, having a significant impact on cell performance. The multi-stack HT-PEMFC is designed to minimize the CO poisoning effect and to maximize its efficiency. The power output that is obtained from each cell stack is presented and the overall power output is compared with single cell stack. Effect of different flow patterns, i.e., co-current and counter-current flow, on the HT-PEMFC stack performance is also presented.