| Use of fuel cells to produce energy is becoming more common, making improvements in hydrogen production necessary. Fuel cells use pure hydrogen to produce electricity, water, and heat. No pollutants are produced, making hydrogen the ideal source of clean energy. Unfortunately, pure hydrogen deposits are not found on earth. This means that hydrogen has to be manufactured from sources like hydrocarbons and water.; Despite the increasing importance of hydrogen as a clean energy source, the basic three-step method used to manufacture hydrogen has changed little from the early 1900's. Producing hydrogen requires steam reforming methane in large furnaces followed by a series of water-gas shift reactors. Finally the hydrogen is purified using pressure swing adsorption. Since fuel cells are designed to be portable devices, methods must be developed to produce hydrogen in small, lightweight, economical reactors.; This research used two reactors to produce hydrogen. In the first, a catalytic wall reactor, steam reforming and water-gas shift of methane were coupled to the catalytic combustion of methane on the opposite sides of a thin wall. This allowed the amount of time required for steam reforming to be reduced from ∼1 second to less than 0.1 seconds. The reactor, the size of a coffee mug, was ideal for producing hydrogen for mobile applications like a laptop computer. The second, a partial oxidation reactor, produced hydrogen by feeding fuel and air to a monolith coated with catalyst. The reactor was smaller and operated even faster than the catalytic wall reactor, requiring only 0.01 seconds for reaction.; Both reactors successfully produced a hydrogen stream suitable for use in a fuel cell. The concentration of CO in the effluent stream was critical since CO is a severe poison for fuel cells. The steam reforming reactor produced an effluent with <1% CO. The partial oxidation reactor produced an effluent with ∼10% CO. However, since the residence time in the reactor was 0.01 seconds, large quantities of hydrogen were produced. Future work needs to focus on obtaining a low CO content in the effluent of the partial oxidation reactor. |
