Characterization and Modeling of a Methanol Reforming Fuel Cell System: Karakterisering og Modellering af en Methanol Reformering Fuel Cell System

Many fuel cells systems today are operated with compressed hydrogen which has great benefits because of the purity of the hydrogen and the relatively simple storage of the fuel. However, compressed hydrogen is stored in the range of 800 bar, which can be expensive to compress.One of the interesting topologies is the Reformed Methanol Fuel Cell (RMFC) system that operates on a mix of methanol and water. The fuel is reformed with a steam reforming to a hydrogen rich gas, however with additional formation of Carbon Monoxide and Carbon Dioxide. High Temperature Polymer Electrolyte Membrane Fuel Cell (HT-PEMFC) has the benefit of being resistant to CO poisoning. The HT-PEM fuel cell operates at elevated temperatures (above 100 ^oC) and therefore uses phosphoric acid as a proton conductor. 

Using a HT-PEMFC in a RMFC system enables the use of exhaust gas from the fuel cell in a catalytic burner which is able to heat up the steam reforming process. However, utilizing the excess hydrogen in the system complicates the RMFC system as the amount of hydrogen can vary depending on the fuel methanol supply, fuel cell load and the reformer gas composition. This PhD study has therefore been involved in investigating the gas composition of the reformer and the affects to the HT-PEM fuel cell. Additional,a focus on the dynamics and system control of the RMFC have been studied, which have also been a big part of the motivation for this work.