Denver Cheddie

Model-based estimation of PEM fuel-cell systems

This paper proposes a model-based observer, which allows for the monitoring of the partial pressures of hydrogen, oxygen assuming that the water vapor during transient fuel cell operation is known. This information can be used to regulate the supply of these gases to the cell whereby maintaining efficient performance. It is not practical to measure the partial pressures of each gas in the catalyst layer; however, it is possible to estimate the vapor pressure in the anode and cathode compartments from the temperature measurements. From this information, the partial pressure of the hydrogen and oxygen can be reconstructed using the fuel-cell model.

Modeling of a SOFC-GT Hybrid Power Plant With Anode Recycling

Power generation using gas turbine power plants operating on the Brayton cycle suffers from low efficiencies and high irreversibilities. In this work, a solid oxide fuel cell (SOFC) is proposed for integration into a 10 MW gas turbine power plant, operating at 30% electrical efficiency (13.7% second law efficiency). The SOFC system entails anode recycling to enable self sustaining reformation reactions, thus alleviating the need for an external water supply and steam generation unit. It also utilizes turbine outlet heat recovery to ensure a sufficiently high SOFC operating temperature. The power output of the hybrid plant is 26.2 MW at 63.4% efficiency (35.3% second law efficiency). The hybrid plant performs best when 70–80% anode recycling is used. A thermo-economic model predicts a payback period of 4.6 years, based on future projected SOFC cost estimates.Copyright