A process simulation study of a newly designed fuel processing system for a high temperature PEM fuel cell unit

Abstract

Fuel cells can be one of the ideal technologies for micro-cogeneration and also for Uninterruptible Power Supply systems (UPS) especially in terms of high reliability, low environmental impact and size flexibility. A micro-cogeneration system provides electricity and heat whereas UPS system provides electricity during a shortcut. Since those units have capacities of 1–5 kWe, they are developed for residential applications. Both UPS and micro-chp units for high temperature PEM fuel cell should contain a fuel processor which converts natural gas, LPG or other hydrocarbons into hydrogen rich (up to 50%molar) synthesis gases via reforming and water-gas shift reactions. These units also contain an afterburner fueled by PEM anode off-gas to provide preheating of inlet streams of hydrogen production reactor.In this work, a newly designed “micro scale compact fuel processing system” for hydrogen rich gas production to be used for a 1 kWe High Temperature Fuel Cell (HTPEM) is presented and thermodynamically analyzed. Natural gas has been simulated as a hydrocarbon fuel source in the flow-sheet model. The overall fuel processing system is simulated using ASPEN HYSYS process simulation package. The simulated fuel processing system (FPS) has been integrated with a high temperature PEM fuel cell unit. FPS has been modeled to determine the thermodynamic characteristics of the overall process. The steady-state simulations have been realized for the overall process. The changes on reactor temperatures, feed flow rates, steam to carbon ratios, compositions and electrical loads have been investigated.