Fuel From Water (excerpt)

Chapter 1: INTRODUCTION WHEN the universe was young there was hydrogen. Within the young stars hydrogen atoms joined to form helium, carbon, and oxygen. As the stars aged and died heavier elements formed - such as gold, lead, and uranium. The Sun, and the Earth are made up of this stardust. The process continues. Today over 90 percent of the detectable matter in the universe is hydrogen but only 0.2% of the earth's atmosphere. In 1776 the British chemist Henry Cavendish discovered hydrogen by dissolving metals in dilute acids. When burned, it produced water. In 1783 the French chemist Antoine Lavoisier named hydrogen from the Greek words meaning "water producer." Hydrogen on Earth is chemically combined with other elements. The most common hydrogen-containing substance is water. There are other sources of hydrogen. It is found in combination with carbon in hydrocarbons. It requires energy to separate hydrogen from the carbon in hydrocarbons or from the oxygen in water. Electrolysis of water. Passing an electric current through water also produces hydrogen. This separates the hydrogen from the oxygen in the water molecule in a process called electrolysis. Steam reforming of methane. Oxygen combines with the carbon in the methane to liberate the hydrogen atoms. Both of these processes require energy to separate the hydrogen. This is why hydrogen is not only a fuel but a way of storing energy. When burned, the combustion of hydrogen and oxygen creates heat, returning some of the energy used to make it available. Heat is released and water is formed. Each water molecule has two atoms of hydrogen and one oxygen - H2O. Some advantages of hydrogen over other fuels are: Hydrogen can be made endlessly from water by use of a water electrolyzer. There are widely varying methods of production. Combustion produces low levels of pollutants in the form of nitrous oxide, but these can be virtually eliminated by various combustion control methods. Hydrogen has the highest energy per unit weight -- three times that of gasoline. Hydrogen can be transported safely in pipelines. Hydrogen is nontoxic. Hydrogen dissipates rapidly in air. This reduces explosion hazards. Some disadvantages of hydrogen are: When mixed with air, hydrogen has a wide range of flammability. This means that it will burn in lower concentrations. It's harder to store than liquid and other gaseous fuels. Hydrogen liquefies at a very low temperature, -253C (-423F|. Small amount of energy on a volume basis; about one-third that of gasoline. High flame velocity and low ignition energy give hydrogen an advantage in engine performance but present special safety problems. Despite the opportunities and challenges of using, hydrogen, there is little doubt that it is our future fuel. Should we start to use it now, or wait for the oil to run out? THE TECHNOLOGY TRAP We take our dependency upon foreign oil for granted. We have failed to measure the full costs of our lethargy. There can be no military solution to our energy dependency. Any serious use of force to keep the oil supply lines open, in opposition to any serious attempt to close them, would cost far more than what we are "saving" by importing oil. We remain energy dependent because we choose to be. We ignore not only the present danger to ourselves but the necessity to eventually find replacements for foreign oil. Almost 75 percent of the world's known oil reserves are in the Middle East. The Western Hemisphere currently has only 16 percent. The U.S. and Canada use twice as much oil per person as Europe. Two-thirds of that is for transportation. To sustain its standard of living, the U.S. must bum 17.3 million barrels of oil every day. Ten point nine million dollars goes into transportation. 58% is imported. Lee Schipper, of the Lawrence Berkeley Laboratory, claims that each American averages 350 gallons of gasoline per year, compared to 150 gallons for West Germany. If the cars Americans drive were as fuel efficient as those in West Germany, another 75 gallons would be saved. There would be, however a deadly tradeoff as more people died in auto accidents in the smaller cars. We are in what Roy McAlister, of the American Hydrogen Association, calls a technology trap. Industry won't supply an alternative fuel if enough people don't want it. Yet consumers want a new fuel only if it cheap and widely available. The deadlock can be broken if consumers would be willing to pay a higher price for energy alternatives until increased production brings the price down.

Natural gas could reduce both air pollution and imported oil. Some utilities sell natural gas for vehicles modified to use it, for about the equivalent of 70 cents per gallon of gasoline. Engine conversion to natural gas is simple, but the fuel storage and delivery systems are complex and expensive. Professional conversions cost up to $3,000 per car. Few of the 210,00 gas stations in the U.S. offer natural gas. At a cost of about $200,000 to convert a station such an investment is unlikely unless there is public demand for it. Theodore Eck, chief economist at Amoco Oil Company, "says that oil companies would provide natural gas if the auto companies would build cars that could use it. Mass production could bring the cost per car down to about $300 extra. The car makers won't build them in the absence of public demand but the public doesn't want them because the fuel isn't available. According to Charles Terrey of the Energy Information Administration, the U.S. will run out in about the year 2025. The purpose of this hook is to explain: How to separate hydrogen from water and hydrocarbons with maximum efficiency. The principle of constructing water electrolyzers. The principles behind converting internal combustion engines to hydrogen fuel. The salt use of hydrogen fuel in all its primary applications. The results of research on use, storage, and production by electrolysis. The metric system of measurement is used. The main units are kilograms, meters, and degrees centigrade, Equivalent English units are shown in parentheses. FROM CARBON TO HYDROGEN Throughout history there has been a trend away from fuels with high carbon content to fuels rich in hydrogen. See Exhibit 1. Methane, with one carbon atom per molecule is gradually replacing heavy oil, with 20 carbon atoms per molecule. When wood was the primary fuel, the ratio of hydrogen to carbon was about 0.1, now it is 4.0, The increasing amount of hydrogen in fuel lowers the boiling point. Recently, the trend has slowed, hydrogen will not be widely used as a fuel before the year 2050 without a commitment to do it sooner. Today hydrogen is used primarily in synthesizing chemicals, methanol production, and petroleum refining. It is valuable in storing energy from electric power plants during hours when power demand is low. Over the course of a day. electrical generating machinery can run at an even rate, thereby reducing costs. Nuclear energy now meets 10% of the world's electrical needs. By 2030 solar energy technology will assume another 10%. "Hydrogen, with its adaptability to solar energy and to other secondary energy carriers, offers the possibility of promoting the introduction of renewable energy sources."

Chapter 2: ELECTROLYSIS WATER SPLITTING Breaking Bonds Electrolysis is a process of producing hydrogen and oxygen from electricity and water. Two hydrogen atoms and one oxygen atom are electrically attracted in a molecule of water. When an electric current passes though water, the chemical bond breaks down giving two positively charged hydrogen atoms (positive ions) and one negatively charged oxygen ion (a negative ion). The negative oxygen ions migrate to the positive electrode (the anode). The positively charged hydrogen ions are attracted to the negative electrode (the cathode). Direct current applied to water results in the following reaction releasing twice as much hydrogen as oxygen.

The electrical resistance of pure water is 100 ohm/cm (254 ohm/in). It can be reduced in one of several ways. 700 to l,000C (1,290 to 1,800F) heat. A salt like sodium chloride An acid such as sulfuric acid, or a base such as potassium hydroxide. Salts tend to corrode electrode metals. At greater expense, platinum and phosphoric acid can be used. Potassium hydroxide (KOH) with nickel-iron (stainless steel) electrodes provides the best compromise between performance and cost. The reaction for an alkaline electrolyte (like KOH) at the cathode is:

Four water molecules break down into eight positively charged hydrogen ions (8H+) and four negatively charged oxygen ions (402-). Each oxygen ion attaches to one hydrogen ion to form four hydroxyl ions (4OH-). Four hydrogen ions remain. Each of them combines with four electrons emitted at the cathode to form four complete hydrogen atoms. Since hydrogen atoms combine in pairs, the four hydrogen atoms combine into two hydrogen molecules (H2). The four negatively charged hydroxyl ions are attracted to the positive electrode. The electrolyte allows the ions to be drawn to the anode by increasing the conductivity of the water. The reaction for an alkaline electrolyte (like KOH) at the anode is as follows.

Four hydroxyl ions give up four electrons to form a molecule of oxygen gas (O2) and two molecules of water. The four electrons enter the anode and complete the electrical circuit, outside the electrolyzer. Exhibit 2 depicts the flow of ions. The anode reaction is an oxidation reaction -- free electrons are produced. The reaction at the cathode is a reduction reaction- free electrons are absorbed. The cathode reaction for an acid electrolyte (such as sulfuric acid, H2SO4) is:

Alkaline electrolytes are less corrosive to electrode material than acids. According to G.A. Crawford, alkaline electrolyte material "... has the most significant near-term commercial potential for recovery of hydrogen from water on a large industrial scale." It is also more convenient to use on a smaller scale. The two most common alkaline electrolytes used are sodium hydroxide (NaOH) and potassium hydroxide (KOH). NaOH is less conductive than KOH, but is cheaper. Since KOH combines with CO2 to produce potassium carbonate, periodic replacement is needed in cells open to the

Atmosphere. However, airtight cells cut down on this loss. High-purity distilled water is needed to eliminate the production of chlorides and sulfates from tap water impurities. These chemicals slowly corrode the electrode material. Even with distilled writer, electrode materials need to be corrosion resistant. The most commonly available materials are: iron cathodes and stainless steel anodes. Electrolysis may be used with other substances. Salt, a compound of sodium and chlorine in the molten state it may be electrically split by a suitably designed electrolyzer to produce solid sodium at the cathode and chlorine gas at the anode. A zinc chloride solution under electrolysis yields solid zinc at the cathode and chlorine gas at the anode. Separators Electrolyzers consist of five elements: Container Electrolyte. Water and a chemical added to conduct electrical current. The chemical may be a salt, acid, or base. Positive electrode (anode) Negative electrode (cathode) Separator. The separator is placed between the electrodes. It allows the current and ions to pass through but prevents the hydrogen and oxygen generated by the electrolysis process to mix. Hydrogen and oxygen forms an explosive mixture. Between 4 and 75% hydrogen in air and 4 and 94% of hydrogen in pure oxygen are explosive. Hydrogen at less than 4% or greater than 75% in air will burn but not explode. Materials such as asbestos fiber work well as separator material because the capillary pressure is greater than the cell pressure. Artificial fiber cloth, rubber cloth, or metallic mesh can also be used. The gap between the electrodes should be as small as possible.