A Science Fair Project
Hydrogen
Fuel of the Future
Shannon L. Smith
2/28/2011
Introduction and Hypothesis
Hydrogen sounds like a terrific fuel source. Hydrogen may be a clean, green alternative to fossil fuels. Hydrogen can be made from hydrolysis of water, but this hydrolysis process requires energy. “Hydrolysis: is a chemical reaction involving water as one of the reacting substances. Its name comes from two Greek words meaning water and loosening. In industry, hydrolysis is important in making soap, sugar, alcohols, hydroxides, and silicones.” (Adewumi) Can hydrolysis be made more efficient in order to provide a clean alternative fuel source, hydrogen, in order supplement fossil fuels upon which we are so dependant?
Why Hydrogen?
Hydrogen is a fuel for the future because it is clean when burned. Fossil fuels are running out, but there is a lot of hydrogen to be made.
Hydrogen could someday replace both gas and oil as a fuel. It burns easily, giving off huge amounts of heat and one harmless by-product, water. Chilled to liquid form, hydrogen can be transported in pipelines and stored in tanks. Aircraft and automobiles may someday use this nonpolluting, lightweight, and efficient fuel. Hydrogen is removed from water by a process called hydrolysis, which involves running an electric current through the water. But the process requires enormous amounts of electric power, making hydrogen a costly energy source. (Adewumi)
Right now there are some hydrogen powered cars on the road. For example there are some fuel cell cars like “Honda's new hydrogen-powered FCX Clarity, which hit the market this week leasing for $600 a month, as well as the hydrogen-powered Chevrolet Equinox test-vehicle fleet from General Motors—part of a pilot program that aims to determine how hydrogen cars might function in everyday life. Both the Japanese and U.S. automakers are betting that these nonpolluting cars will one day replace the internal combustion engine.” (Biello) Auto makers are pursuing hydrogen fueled vehicles:
”Hydrogen (H2) is being aggressively explored as a fuel for passenger vehicles. It can be used in fuel cells to power electric motors or burned in internal combustion engines (ICEs). It is an environmentally friendly fuel that has the potential to dramatically reduce our dependence on imported oil, but several significant challenges must be overcome before it can be widely used.” (Fuel Economy.Gov. “Hydrogen.”)
Hydrogen is a useful, clean fuel source. However, the electricity needs to come from a clean source like solar power in order to avoid burning fossil fuels to make clean hydrogen. Also, people with solar powered homes may be able to store hydrogen to use as fuel during cloudy weather when they are unable to generate electricity from their solar cells. Mike Strizki has powered his home, cars and lawn mower in this manner.
A home owner could pay a lot of power and heating bills with the cost of solar/hydrogen equipment used in this “hydrogen house.” At this time hydrogen is really expensive to produce, but it could be made here, where we live, instead of us importing fossil fuel from oil producing countries. (Fuel Economy. Gov. “Benefits.”) Mike Strizki says his equipment cost $500,000. (Biello) That’s very expensive, a lot more expensive than fossil fuels. Besides the costly equipment there are some other draw backs to hydrogen fuel at this time. It does not have the same energy output we are used to.
Hydrogen contains much less energy than gasoline or diesel on a per-volume basis, making it difficult for hydrogen vehicles to go as far as gasoline vehicles between fill ups—about 300 miles. Technology is improving, but the onboard hydrogen storage systems do not yet meet size, weight, and cost goals for commercialization. (Fuel Economy.Gov)
My Experiment
I wanted to see whether I could make hydrolysis a more efficient process.
Apparatus
I conducted my experiment using a plastic tank to hold the water with a wooden slat to hold the electrodes. We purchased two test tubes to hold and measure the hydrogen that is being generated. The two test tubes are held upside down over the electrodes. The electrodes are made of graphite that we had gotten out of a large pencil and to which we attached wires leading to a car battery. We used an instant read thermometer to measure the temperature of the water. We also used a stop watch to measure the amount of time it took to generate one ml of hydrogen. We used a car battery instead of a solar cell because it can be used indoors and provides a more consistent source of electricity.
Procedure
In each test, I filled the tank with water at the right temperature. Then I put the electrodes in the bottom of the tank, and filled the test tubes with water. I then put the test tubes upside down in a holder over each electrode. Then I hooked up the wire to the battery and started the stop watch. I watched the test tube until one ml of hydrogen was generated and stopped the watch. The test was repeated for each temperature and for each amount of salt.
Test Runs
I ran two types of tests. During the first test I added heat in varying increments to tap water. I measured how long it took to generate one ml of hydrogen at that specific temperature.
My Results for Test #1
In my second test I measured how fast the hydrogen is produced with various measurements of salt dissolved in tap water.
My Results of Test #2
Analysis
Warmer water speeds up the hydrolysis process. I found that if I increased the temperature of the tap water to 140F in the hydrolysis process, I collected three times the amount of hydrogen in the same time period as I collected when the water was 40F. The sun could be used to heat the water in hydrolysis. In the solar-powered hydrolysis system, the sun produces the electricity and also heats up the water.
Also, adding salt to the water speeds up the hydrolysis process even farther. Salt increases the conductivity of the water, so electricity flows more easily through the water. ”When salt is added (NaCl) to the system, the conductivity of the system increases considerably.” (Silva, Water Conductivity). Because salt increases the conductivity of water to electricity, more electricity is used in the process. Thus, hydrogen is generated faster, but not necessarily more efficiently. There are limits to the effects of salt. Once the water reaches a saturation point with salt, the rate of collection of hydrogen does not increase.
Regarding the cleanliness of the hydrolysis process, when I used warmer water in the hydrolysis process I collected hydrogen more quickly; however, because more electricity is used in the presence of salt and more energy is needed to preheat the water the addition of these factors, salt and heat, may not create a more efficient hydrolysis process. The use of solar power may be a more “green” and economical option, however. (Cullen)
Further Research
There are more experiments that I could do to see what may make hydrolysis faster. I could try other chemicals, such as lime, potassium salt, vinegar, or baking soda to see if they would speed up the hydrolysis process. I could also try different materials for the electrodes. In my experiments, the electrodes were made of graphite from pencil leads. Other things I could try may be different metals, such as aluminum, iron, copper, and platinum.
Conclusion
I have found that adding salt to water increases the speed at which hydrolysis occurs. I have also found that raising the temperature of the water increases the speed at which hydrolysis occurs. In both cases hydrogen is produced from hydrolysis more quickly. Although hydrogen is produced more quickly, this does not mean that increasing the salt content or the water temperature is a means to more efficiently extracting hydrogen. The process may use more electrical power when it is accelerated; however, measuring the output of energy required to cause hydrolysis was beyond the scope of my project.
Bibliography
Adewumi, Michael A. "Energy supply." World Book Student. World Book, 2011. Web. 22 Feb. 2011.
Biello, David. “House: No More Power Bills—Ever.” Scientific American. June 19, 2008.
Cullen, T. Pure Energy Solutions.Com. News. “Sunlight Used to Produce Hydrogen from Water: Solar Hydrogen Energy Corporation Has Demonstrated That Solar Energy can be Concentrated to 1500F and used to Produce Hydrogen.” http://www.pureenergysystems.com/news/2004/07/09/6900033_Solar_Hydrogen/. July 9, 2004. Accessed February 26, 2011.
http://www.scientificamerican.com/article.cfm?id=hydrogen-house. Web. 28 Feb. 2011.
Hydrogen. http://www.fueleconomy.gov/feg/hydrogen.shtm. Site updated February 25, 2011. Accessed February 26, 2011.
Silva, Vasco. Water Conductivity: Science at Home. Http://scienceathome.cienciaviva.pt/conduti_agua_eng.html. 2003. Accessed February 26, 2011.
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