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ChE 466/566 Lecture 1. Fuel Cell and Hydrogen Technology (ChE466/566: 466 for undergraduates and 566 for graduates) (3 Credits, Tu Th 2:35-3:50 pm, JH-203) Department of Chemical Engineering New Mexico State University. Instructors . Dr. Shuguang Deng Jett Hall 253 (Office)
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ChE 466/566 Lecture 1 Fuel Cell and Hydrogen Technology (ChE466/566: 466 for undergraduates and 566 for graduates) (3 Credits, Tu Th 2:35-3:50 pm, JH-203) Department of Chemical Engineering New Mexico State University
Instructors Dr. Shuguang Deng Jett Hall 253 (Office) Tel: 575-646-4346 e-mail: sdeng@nmsu.edu
Course Description This course presents an introduction to the fundamentals and applications of fuel cell and hydrogen technology. It includes thermodynamics, electrochemical kinetics, fuel cell electrode catalysts, fuel cell systems, fuel reforming and H2 production, hydrogen storage, hydrogen safety. The applications of fuel cells in power generation, portable power, and automotives will also be covered. Students will also have a chance to work on a term project, write a term paper and present the term project.
Textbooks • Ryan P. O’Hayre, Suk-Won Cha, Whitney Colella and Fritz B. Prinz “Fuel Cell Fundamentals”, John Wiley & Sons, Inc, ISBN: 13 978-0-471-741-48-0 (2006). • “Fuel Cell Handbook”, 7th Edition, DOE/NETL-2004/1206, EG&G Technical Services, Inc. Science Applications International Corporation (Nov., 2004).
Grading There will be two exams and one term paper and presentation. The guidelines for term paper and presentation will be provided. Quiz 10% Exam-1 20% Exam-2 40% Term Paper 20% Presentation 10% A:85-100; B:75-84; C:65-74; D:60-64; F:<60
Course Webpage http://cheme.nmsu.edu/~sdeng/ChE466 Login Name: che466 Login Password: pemfc
Course Schedule 30 Sessions 26 Lectures 2 Exams 2 Final presentations
Fuel Cell Basics Battery vs. fuel cells What is fuel cell? Why do we need fuel cell? How does it work? Where do we use it?
Battery A device that converts chemical energy stored in a battery directly to electrical energy. It is a closed system.
Volta’s Battery (1800) Alessandro Volta 1745 - 1827 Paper moisturized with NaCl solution Cu Zn
A Simple Fuel Cell Expt. • Apparatus • One small glass with water and a common salt • One voltmeter with ranges of 0-2 and 0-20 VDC • One 4.5 volt battery • Experimental cables with small crocodile clips • 2 platinum wires as electrodes
Fuel Cell Expt. H2O H2 + ½ O2
Fuel Cell Expt. H2 + ½ O2 H2O
Electrolysis / Power consumption Chemical Reactions Electric Power Electrochemical battery / Power generation Electric Power Conversion
Fuel Cell A device that converts the chemical energy stored in a fuel directly to electrical energy. It is an open system.
Design and Technology Replacement technology - Replaces an existing product electric vs. gas light - New product must cost less Enabling technology - Provides new capability airplanes ––> flight - Cost not so important
Fuel Cell Advantages Fuel cells are needed because fuel cells possess: 1). the advantageous characteristics of high-energy conversion efficiency 2). environmental benign operation 3). alleviate and eliminate dependence on fossil-fuel reserves 4). flexible for a variety of different applications 5). compatible with renewable energy sources 6). carriers for energy security, economic growth, and sustainable development.
Fuel Cell Disadvantages • Too expensive for many applications • Power density limitation • Fuel availability and storage • Operation temperature compatibility concerns • Susceptibility to environmental poisons • Durability under start-stop cycling
PEM Fuel Cell Basics H2 + ½ O2 Energy + H2O + Waste Heat
PEM Fuel Cell Basics • Reactants (such as H2 or O2) transferred to the porous electrode surface, and the gas/electrolyte interface. • 2. The reactant dissolves into the liquid electrolyte at the two-phase interface. • 3. The dissolved reactant then diffuses through the liquid electrolyte to arrive at the electrode surface. • 4. Some pre-electrochemical homogeneous or heterogeneous chemical reactions may occur, such as electrode corrosion reaction, or impurities in the reactant stream may react with the electrolyte. • 5. Electroactive species (which could be reactant themselves as well as impurities in the reactant stream) are adsorbed onto the solid electrode surface.
PEM Fuel Cell Basics 6. Adsorbed species may migrate on the solid electrode surface, principally by the mechanism of diffusion. 7. Electrochemical reactions then occur on the electrode surface wetted by the electrolyte the so-called three phase boundary, giving rise to electrically charged species (or ions and electrons). 8. Electrically charged species and other neutral reaction products such as water, still adsorbed on the electrode surface, may migrate along the surface due to diffusion in what has been referred to as post-electrochemical surface migration. 9. The adsorbed reaction products become desorbed.
PEM Fuel Cell Basics 10. Some post-electrochemical homogeneous or heterogeneous chemical reactions may occur. 11. Electrochemical reaction products (neutral species, ions and electrons) are transported away from the electrode surface, mainly by diffusion but also for the ions, influenced by the electric field set up between the anode and cathode. The electron motion is dominated by the electric field effect. 12. Neutral reaction products diffuse through the electrolyte to reach the reactant gas/electrolyte interface. 13. Finally, the products will be transported out of the electrode and the cell in gas form.
Electrodes and Electrolyte • Functions of Electrodes • Provide a place for the electrochemical reaction to occur easily (reaction sites) • Provide a flow path for reactant supply to, and product removal from, the reaction sites • Collect the electrons and provide a flow path for electron transfer • Functions of Electrolyte • An ion conductor • An electron insulator • A barrier to separate the reactants (H2 and O2 in PEMFC)
Fuel Cell Applications • Automotive applications (~100 kW) • Portable power applications (<200 W) • Residential applications (1-5 kW) • Onsite cogeneration power plants (0.2 – 1 MW) • Distributed electric power generation (2-20 MW) • Baseload electric power generation (100-300 MW)