The operation of such factories by standard fuels increases the ratio of pollution due to their residual toxic gases that are the result of fuel arson. From this, a need for producing energy sources is emerged; environmentally friendly inherently and relatively low cost.
The bipolar plates may be made of different types of materials, such as, metal, coated metal, graphiteflexible graphite, C—C compositecarbon — Fuel cells essays composites etc.
The electrolyte could be a polymer membrane. Proton exchange membrane fuel cell design issues[ edit ] Cost. A recently published article demonstrated how the environmental burdens change Fuel cells essays using carbon nanotubes as carbon substrate for platinum.
In this type of fuel cell, the membrane must be hydrated, requiring water to be evaporated at precisely the same rate that it is produced.
If water is evaporated too quickly, the membrane dries, resistance across it increases, and eventually it will crack, creating a gas "short circuit" where hydrogen and oxygen combine directly, generating heat that will damage the fuel cell.
If the water is evaporated too slowly, the electrodes will flood, preventing the reactants from reaching the catalyst and stopping the reaction. Methods to manage water in cells are being developed like electroosmotic pumps focusing on flow control. Just as in a combustion engine, a steady ratio between the reactant and oxygen is necessary to keep the fuel cell operating efficiently.
The same temperature must be maintained throughout the cell in order to prevent destruction of the cell through thermal loading.
Durability, service lifeand special requirements for some type of cells. Current service life is 2, hours about 75, miles.
In these cells phosphoric acid is used as a non-conductive electrolyte to pass positive hydrogen ions from the anode to the cathode. These cells commonly work in temperatures of to degrees Celsius. This high temperature will cause heat and energy loss if the heat is not removed and used properly.
This heat can be used to produce steam for air conditioning systems or any other thermal energy consuming system. Since the hydrogen ion production rate on the anode is small, platinum is used as catalyst to increase this ionization rate.
A key disadvantage of these cells is the use of an acidic electrolyte.
This increases the corrosion or oxidation of components exposed to phosphoric acid. Solid acid fuel cell Solid acid fuel cells SAFCs are characterized by the use of a solid acid material as the electrolyte. At low temperatures, solid acids have an ordered molecular structure like most salts.
At warmer temperatures between and degrees Celsius for CsHSO4some solid acids undergo a phase transition to become highly disordered "superprotonic" structures, which increases conductivity by several orders of magnitude.
Alkaline fuel cell and Alkaline anion exchange membrane fuel cells The alkaline fuel cell or hydrogen-oxygen fuel cell was designed and first demonstrated publicly by Francis Thomas Bacon in It was used as a primary source of electrical energy in the Apollo space program.
The space between the two electrodes is filled with a concentrated solution of KOH or NaOH which serves as an electrolyte. H2 gas and O2 gas are bubbled into the electrolyte through the porous carbon electrodes.
Thus the overall reaction involves the combination of hydrogen gas and oxygen gas to form water. This type of cell operates efficiently in the temperature range K to K and provides a potential of about 0. High-temperature fuel cells[ edit ] Main article: Solid oxide fuel cell Solid oxide fuel cells SOFCs use a solid material, most commonly a ceramic material called yttria-stabilized zirconia YSZas the electrolyte.
Because SOFCs are made entirely of solid materials, they are not limited to the flat plane configuration of other types of fuel cells and are often designed as rolled tubes.
Oxygen gas is fed through the cathode, where it absorbs electrons to create oxygen ions. The oxygen ions then travel through the electrolyte to react with hydrogen gas at the anode. The reaction at the anode produces electricity and water as by-products.
Carbon dioxide may also be a by-product depending on the fuel, but the carbon emissions from an SOFC system are less than those from a fossil fuel combustion plant. However, since hydrogen is necessary for the reactions listed above, the fuel selected must contain hydrogen atoms.
For the fuel cell to operate, the fuel must be converted into pure hydrogen gas. SOFCs are capable of internally reforming light hydrocarbons such as methane natural gas propane and butane.
One such challenge is the potential for carbon dust to build up on the anode, which slows down the internal reforming process.
Research to address this "carbon coking" issue at the University of Pennsylvania has shown that the use of copper-based cermet heat-resistant materials made of ceramic and metal can reduce coking and the loss of performance.
Despite these disadvantages, a high operating temperature provides an advantage by removing the need for a precious metal catalyst like platinum, thereby reducing cost.
As temperature decreases, so does the ionic conductivity of YSZ. Therefore, to obtain optimum performance of the fuel cell, a high operating temperature is required.Essay on Hydrogen Fuel Cells Vs. Gasoline. Words 5 Pages. Hydrogen Fuel Cells Vs. Gasoline: Who’s Down With HFC? ABSTRACT: The world’s oil supply is a diminishing nonrenewable resource.
Soon, a new fuel for automobiles will be needed. Hydrogen as an Alternative Fuel Essays Words | . Hydrogen Fuel Cells The Fuel Of The Future Environmental Sciences Essay. Print or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of UK Essays.
Fortunately, there is an answer to this problem: hydrogen fuel cells. Because hydrogen fuel cells are an emission-free fuel source. This free Science essay on Fuel cells is perfect for Science students to use as an example.
Essay about Fuel Cells. Advantages of a Hydrogen Fuel Cell 1.
It can be a renewable source of electricity if the hydrogen comes from a renewable resource. The Poylmer Electrolyte Membrane Fuel Cell - A fuel cell is mainly used to provide electricity from chemical reactions.
It harnesses the chemical energy of hydrogen and oxygen to generate electricity without combustion one of the basic types of fuel cells is the Polymer Electrolyte Membrane Fuel Cell (PEMFC). Fuel cells were the best solution of this issue and there for they are called green energy cells.
Fuel cell is a low pollution power generator. It works as an electrochemical device because it converts the chemical energy stored in gas fuel into electrical energy[2,3].