Hydrogen Fuel Versus Fossil Fuel
Hydrogen is a natural element which combines with oxygen to form water.
The hydrogen element is not a source of energy, but it is a carrier of energy because a great deal of extraction energy is required to make an extraction of hydrogen from water. However, it is used as an energy source in batteries and fuel cells. There is a lot of research that is underway to develop efficient technology that can allow exploitation of the hydrogen energy potential. This dream may solve many problems associated with fossil fuels. These problems include the high fuel costs, pollution from oil spills and combustion as well as probability of exhaustion of fossil fuel resources (Lau & Padro, 2000).
Hydrogen fuel is preferred because it is a clean source of energy that does not emit greenhouse gases during combustion. It also burns to produce higher levels of energy than fossil fuels (Lau & Padro, 2000). Despite these advantages the design and use hydrogen fuel technology and systems has been very challenging. Firstly, the technology of production, storage, distribution and burning of hydrogen has not been put in place and may be very challenging to establish. Secondly, the design of internal (IC) combustion engines is very challenging due to the chemical properties of hydrogen. Hydrogen has very wide flammability range, this may be an advantage in some considerations, but it creates constraints on IC engine design. The ‘hot spots’ in an engine may cause pre-ignition, or “pinging” as known in hydrocarbon engines. This is bound to be a problem because hydrogen has a low ignition temperature. Hydrogen also has a high flame temperature during combustion. The high temperature is a benefit in principle, but because air is 80% Nitrogen the high heat may cause oxidation of nitrogen which will result to nitrogen oxides emissions (pollutants). The challenge about how sufficient H2 can be manufactured economically as well as the infrastructure to supply it nationally is unsolved. H2 may require greater amounts of storage space on automobiles because it cannot be highly compressed and thus there is a need for frequent refueling after short distances.
A comparison of hydrogen (H2) to CH4 based on equal masses seemingly shows that there is a 16/2 merit (on molecular weights) in favor of H2; but, on basis of equal energy H2O=H2 +1/2 O2 in comparison with 2O2+CH4 =2H2O +CO2 with all components in the gas state the advantage is ~3.6 (Tim, 2004). This is because a great amount of energy is derived from the process of forming CO2. Another un-addressed issue with potential challenges is potency of water as a greenhouse gas. The combustion within hydrogen IC engines releases water vapor. The high release of water to the atmosphere may result in trading smog for fog, and this is another unaddressed potential challenge (Tim, 2004).
Hydrogen also has a smaller quenching distance compared to gasoline. As a result, flames from combusting hydrogen travel close to walls of the IC engine’s cylinders before they extinguish. This makes it difficult to quench flames of H2 compared to gasoline. This small quenching distance may increase the backfiring tendency because the air-hydrogen mixture’s flame easily goes through intake valves that are nearly closed compared to air-hydrocarbon flames (College of the Desert, 2001).
Conclusively, hydrogen may be a cleaner fuel, but the challenges posed by its chemical properties and production necessitate further research for its use to be implemented.
References
College of the Desert, (2001). Hydrogen Use in Internal Combustion Engines. Retrieved on 11
th
August, 2010. Retrieved fromhttp://www1.eere.energy.gov/hydrogenandfuelcells/tech_validation/pdfs/fcm03r0.pdf.
Tim, D, (2004). Hydrogen versus Fossil Fuels. Retrieved on 11th August, 2010 from http://www.newton.dep.anl.gov/askasci/phy00/phy00886.htm.
Lau, F. and Padro, G.E.C, (2000). Advances in hydrogen energy. New York, NY: Springer Publishers.
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