The UAS unit operation by Dr. Tragner was designed as a basic model of a Polymer Electrolyte Fuel Cell. The polymer Electrolyte Fuel Cell includes the Membrane Electrolyte Assembly (MEA) and the gas pretreatment unit operations. The pretreatment units are a compressor for the gas on the Cathode side of the membrane, two humidifiers, and two heat exchangers. On the Anode side, the model calculates the stream data for the feed, the Humidified feed, the Temperature Controlled feed, and the product. On the Cathode side, the model calculates the stream data for the feed, the Compressed feed, the Humidified feed, the Temperature Controlled feed, and the product. Results also include a detailed Reaction Energy report and a detailed heat balance with efficiencies and electric power generation.
The process includes pretreatment of the fuel gas on the Anode side and the oxidant gas on the Cathode side. The required gas stream inputs for the MEA are temperature, pressure, and relative humidity. If the gases are too dry, the membrane will stop functioning. For Polymer Electrolyte Fuel Cell Unit Operation, the user must supply the relative humidity of both product streams.
The Anode feed (H2) and the Cathode feed (O2) are external feeds. The Anode and Cathode humidifier water streams are calculated by the model.
The MEA is modeled by the consumption of hydrogen in this reaction:
H2 + ½ O2 à H2O
The performance of the MEA is predicted from its Voltage - Current Density Characteristic equation.
See the Terminology section for the equation details.
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