Browsing by Subject "Hydrogen as fuel"

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    A basic model of hydrogen circulation in a proton exchange membrane (PEM) fuel cell
    (Texas Tech University, 1999-12) Akgerman, Bora
    The fuel cell has come a long way since Sir Hubert Davy built the first prototype in 1801. After a slow 150 years, the fuel cell came to the attention of the world with the first slew of fuel cell operated vehicles in the 1950's. The next decade saw fuel cells used in NASA's Gemini and Apollo space missions. The 1990's have seen fuel cells in power plants, city busses, and space shuttle missions. Currently, $1 billion has been invested worldwide to investigate fuel cell operated vehicles as an alternate to Internal Combustion Engine (ICE) operated vehicles. With fuel cell efficiencies nearing 50%, low emissions and better reliability, fuel cell research is at an all-time high. This research will investigate the performance of the hydrogen circulation system of a Proton Exchange Membrane (PEM) fuel cell specifically designed for a hybrid vehicle. System parameters will be analyzed to find the optimum operating conditions for the hydrogen circulation system.
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    Evaluating the power capabilities of a hydrogen fuel cell
    (Texas Tech University, 1999-05) Turner, Wallace D. L.
    The hydrogen fuel cell has become a very important dc source that has many applications including transportation, power stations, and space missions. The voltage per cell is limited, however, the current density per surface area is very large. So, very high power can be produced from a fuel cell with a low voltage. This thesis describes testing done on a solid polymer proton exchange membrane fuel cell that produces 1 volt maximum per cell with 300A test maximum load. The focus of this report deals with evaluating the power capabilities and characteristics of the 4 cell stack using a test stand. In this effort, it is possible to understand the implications of implementing a one hundred, and ten cells stack into an automobile.
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    Multi-physics modeling of cold plasma reformers
    (2016-12) Pacheco Zetino, Jose Mauricio
    Hydrogen, as a clean energy carrier, reduces carbon emissions. With the fast development of fuel cell vehicles, the demand for hydrogen is increasing. The mainstream production of hydrogen is through steam reforming, requiring high temperature and large scale facilities. The distribution is through high pressure gas cylinders. The installation of hydrogen cylinders in households without professional handling can be dangerous. Compared to steam reforming, the pulsed cold plasma reforming method is a promising way to generate hydrogen in small scale stationary and mobile platforms. In this thesis, a Multiphysics model, analysis, and study of a pulsed cold plasma reforming chamber are presented. Results in terms of electromagnetic field, thermal analysis, and electrical currents are shown both via simulation and experimentally in order to validate the accuracy of the model. This research will generate new opportunities for the optimization process of design of cold plasma chambers for the hydrogen generation process which can in turn introduce substantial savings in costs and time during the research and development phase of this type of products.
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    On-board hydrogen production for fuel cell vehicles via a membrane separator and an externally-fired methanol reformer
    (Texas Tech University, 2004-05) Mathakari, Sushil Prakash
    Many options exist for on-board hydrogen production from liquid fuels for fuel cell powered vehicles. This paper reports on design and construction of an on-board system for hydrogen production from methanol. Methanol reforming is accomplished using an externally fired catalytic reactor. Carbon monoxide, separated from the reactor effluent by a membrane separator, is consumed with the reactor fuel. The reactor is operated at 1950 kPa to supply gas to the membrane separator at its maximum design pressure, and at a temperature of 500°C, to minimize the amount of methanol remaining the reactor product. The design methanol feed rate of 0.32 1/min used for the prototype should be sufficient to supply a 10 kW fuel cell package, but the design can easily be expanded to larger sizes. The membrane separator is an off-the-shelf, polymer-based model, and it is not expected to reduce the carbon monoxide to below 10 ppm, required by proton exchange membrane fuel cells, being considered for vehicular power. For this reason it is necessary to include a selective oxidation reactor to remove the carbon monoxide as a contaminant. An adiabatic energy balance indicates that 30% excess energy is available from combustion of the separated carbon monoxide when used as fuel to the reformer. The thesis includes the design of methanol reformer system, calculation of heat transfer coefficients and heat transfer areas required for the heat exchange of the exhaust gases and the reaction mixture. It also includes the simulation of the entire process using ChemCAD as a chemical process simulator.