Utilization of coal as an energy source

1. I. ENERGY AND TRANSPOTATION I.1. Energy sources Utilization of coal as an energy source Coal replaced wood as the principal source of energy in the United States by the 1890s. The first coal-fired power plant was built in 1882, generating steam that turned a generator to make electricity. In 1884, Charles Parsons developed the more efficient high-speed steam turbine. By the 1920s, pulverized coal increased efficiency and reduced the air needed for combustion. The 1940 cyclone furnace used poorer-grade coals and produced less ash. Recently chemical technology has developed the combustion of culm (waste material from coal mining) to produce power and to decrease environmental load. Charles Parsons Parsons’ Steam turbine (1907) Petroleum exploration and production The 1901 discovery of the vast Spindletop oil field in Texas and the emergence of the automobile caused petroleum to surpass coal as the principal fuel source by 1951. The chemical technology of refining crude oil to separate its different chemical fractions has been continually improved, starting with simple atmospheric distillation and progressing to vacuum (reduced pressure) distillation to thermal cracking to the use of catalysts. For the primary crude oil recovery process, chemistry is most evident in diamond drilling bits, drilling muds, and oil-from-shale extraction using a combination of chemicals and steam. The secondary recovery processes include pumping high pressure gas (carbon dioxide) or water solutions into the earth. Nuclear energy The first nuclear reactor was developed in 1942 for military use. The application of nuclear technology to peaceful uses, including the generation of electrical power, began in 1951 with President Eisenhower’s Atoms for Peace program. Chemistry has played an integral role ever since, producing the radioactive materials used as fuel in the reactors, the reactor control rods that regulate the flow of neutrons from radioactive decay, the reprocessing of spent fuel rods, waste-management, environmental protection, and minimizing the harmful effects of radiation exposure. Alternative energy sources Green methods for power generation, such as wind, hydroelectric, and geothermal, account for less than one percent of the world’s total power generation, but they play an increasingly important role, as determined by economics and availability. Through chemistry, solar panels for both thermal and photovoltaic generation, lightweight carbon fiber propellers for wind generation, concrete and metal turbines for hydroelectric plants, and corrosion-resistant materials for harnessing geothermal sources have all been developed.

2. I. ENERGY AND TRANSPORTATION I.2. Electrical Energy Storage and Portable Power Sources Single-use batteries Electrical energy storage was developed by Alessandro Volta in the late 1700s, and chemistry has contributed to the subsequent improvements in battery power. The 1890 carbon-zinc dry cell battery improved upon the earlier Leclanché ’wet-cell’ design. It was commercially produced for use in flashlights and it is still in use today. In 1949, a new alkaline paste for the traditional battery enhanced lifetime and allowed for miniaturization. This alkaline battery quickly found many uses in portable electronic devices and cameras. Since then, newer battery models have used silver oxide, mercuric oxide, or lithium. Carbon-zinc dry battery Rechargeable batteries The 1859 lead-acid rechargeable battery was an early commercial example of using a controlled chemical reaction to produce electricity. Improved upon in 1881 and continuously enhanced since, the lead-acid battery continues to be the dominant form of battery used in automobiles and trucks. The nickel-cadmium rechargeable battery, first built in 1899, was too expensive to compete commercially. Modern developments have focused on lithium. After a failed attempt to utilize lithium metal in the 1980s, lithium-ion batteries are now commonplace, finding applications in cellular phones and laptop computers. Rechargeable batteries

3. I. ENERGY AND TRANSPORTATION I.3. Materials for Roadways and Bridges Concrete The massive U.S. interstate construction projects of the 1950s depended heavily on the strength and longevity of concrete for roads and bridges. Portland cement, first made in 1824 and patented as reinforced concrete by the Frenchman Joseph Monier in 1877, slow-sets due to a complex chemical reaction in which the cement paste fills the voids between particulates and other reinforcements. Its durability and strength depend on careful control of the cement manufacturing process Adding different chemicals to the initial concrete mixture can reduce shrinkage and improve corrosion resistance. Asphalt Asphalt is a popular road construction material because of its cost and performance advantages. Natural asphalt was discovered in 1595, but it was not bound with coal tar and used to pave roadways until 1902. Bitumen, the solid or semi-solid residue of the petroleum refinery process, quickly replaced natural asphalt for paving roads. Recently, synthetic polymers have been added to improve performance and durability. Superpave (an acronym for Superior Performing Asphalt Pavements) is the latest technique for making superior asphalt that can withstand heavy loads and adverse weather conditions. Metals and alloys Steel has become the primary structural material for bridges due to its light weight, strength, durability, ease of maintenance and construction, low erection costs, and resistance to natural disasters such as earthquakes. New high-performance steels introduced in the 1990s have superior strength and corrosion resistance. Another technology for protecting steel in bridge construction is a process known as metalizing, in which aluminum or zinc is sprayed onto a cleaned steel surface to form a 30-year protective coating. Maintenance and repair techniques Road infrastructure must be maintained without significant deterioration in all types of weather and on a long timescale. Innovations in construction and maintenance materials have allowed longer intervals between the rebuilding of roads. Sealants for concrete, asphalt, and steel are important to prolonging road life. Other chemical and polymeric materials function as binder additives to enhance the performance of asphalt roadways. For example, styrene-butadiene-styrene results in less rutting and cracking.

4. I. ENERGY AND TRANSPORTATION I.4. Petrolchemical fuels Production of gasoline from crude oil To improve gasoline recovery from crude oil, refiners initially used heat to break down the larger molecules of the heavy oil fraction into the smaller ones found in gasoline, using a process called thermal cracking (1913). Since high temperatures also formed unwanted byproducts, a vacuum distillation process that operated at lower temperatures was in use by 1928. The use of an inert catalyst (catalytic cracking) rather then high temperatures to achieve cracking was developed by Eugene Houdry in 1936, introduced commercially in 1937, and quickly revolutionized the gasoline refining process. Oil refinery Fuel additives Early automotive engines ‘knocked’ whenever poor quality gasoline was used. In 1921, tetraethyl lead was added to gasoline to make engines run more smoothly and quietly. By 1926, an octane rating was introduced to measure the quality of gasoline (compression tolerance). The use of lead additives was discontinued in the 1970s because of environmental concerns. Today, small amount of chemicals (alcohols, ethers) are added to gasoline to improve octane rating, enhance gasoline performance (metal deactivators), and reduce engine friction and wear to extend engine life (detergents). Seasonal chemical additives are used in some areas for geographical concerns, such as the addition of methanol to prevent fuel line freezing. Catalytic converters Two-stage catalytic converters were introduced in 1975 to control carbon monoxide and hydrocarbon emissions. Soon, a third stage was added to clean nitrogen oxides from the exhaust. Catalytic converters function by causing a series of chemical reactions to occur around the metal, usually platinum catalyst. Nitrogen oxides are converted into nitrogen and oxygen gases, carbon monoxide is converted into carbon dioxide, and the unburned hydrocarbons are converted to water and carbon dioxide. Three stage catalytic converter

5. I. ENERGY AND TRANSPORTATION I.5. Automotive vehicles Advanced materials for design, comfort, and safety The automobile of 21st century bears little resemblance to its early predecessors in design, comfort, and safety for passengers. High-intensity discharge headlamps allow maximum nighttime illumination. Corrosion has been drastically reduced by special coatings and materials. Chemical refrigerants circulate in a closed-environment system. Automotive safety glass was introduced in 1914. Today, special polymers coat glass to reduce weight and outside noise and to protect from glare and ultraviolet radiation. Safety innovations include polymer fibers in seat belts (required in the 1960s) and in air bags (required in 1996). Plastic components Reducing the weight of automobiles by transitioning from metal to plastics and identifying new high-performance materials is made possible by chemical achievements. After World War II., automobile manufacturers began using synthetic petroleum-based polymers for rigid structural components because of their toughness, hardness, and weather resistance. After the 1970s energy crisis, lightweight alternatives were sought for metals in order to improve fuel efficiency. Design applications include: complex body shapes fabricated by injection molding, thermoplastic bumpers, polypropylene fibers that are colorfast and UV-stable, and special paints, coatings, and adhesives. Polypropilene fibers Tire technology Natural rubber products appeared in the early 1800s, but were impractical due to softening or brittleness in hot or cold weather. An American inventor Charles Goodyear developed the vulcanization process for natural rubber in 1839, linking unsaturated bonds with sulfur. This basic process is still used with additional chemical accelerants and stabilizers. By 1945, synthetic rubber was being produced commercially. As tire demand increased, other improvements were introduced, including an inner tube to replace solid rubber tires, reinforcement with natural or synthetic fabric cord for strength, added materials for reduced wear, and the eventual debut of tubeless tires.

6. I. ENERGY AND TRANSPORTATION I.6. Aeronautics Hot-air balloons From 1783, when the first human flew in a balloon propelled by the hot air rising from an open flame, innovations in hot-air balloons have been revolutionary. Hot air was quickly replaced by hydrogen, which was easier to controll. Hot-air ballooning has become a popular sport with more than 5000 hot-air balloon pilots in the United States. Chemistry has contributed the durable, inexpensive and heat-resistant nylon fabric and the liquid propane technology used for propulsion. Helium Although hydrogen-filled balloons, such as the infamous Hindenburg (1937), had rigid structures, the flammability of hydrogen always posed a safety hazard. In 1905, two chemists discovered natural helium in a Kansas gas well, and this rare element was suddenly plentiful. During World War I., chemical technology extracted, stored, and shipped large quantities of helium, and the helium-filled blimps in World War II. safely escorted troop and supply ships around submarines. In the 1950s, helium was used as welding atmosphere during rocket construction and as the propellant which pushed the rocket’s fuel to the engines. The Hindenburg disaster (1937) Rocket fuels From the early test rockets first launched in the 1920s, to communication satellites of the 1950s, to the reusable Space Shuttle of the 1980s, the human expansion into space is an amazing engineering feat. Successful space travel depends on rockets possessing the high thrust-velocity to overcome the gravitational force of the Earth. The first rocket was launched in 1926 using a liquid fuel of gasoline and liquid oxygen oxidizer. Subsequently, different fuels and oxidizers have been used in either solid or liquid form. The Space Shuttle uses liquid hydrogen as fuel, but the launch engines use a solid fuel of aluminum and ammonium perchlorate as the oxidizer/binder. Construction materials for aircraft and rockets As aircraft design has evolved from wood and fabric to sophisticated engineered materials, chemical technology has provided materials that met design requirements. Metal alloys using aluminum and titanium were developed to provide strength, light weight, high-temperature stability, and corrosion resistance for aircraft. Rockets have special material requirements because of the extreme conditions under which they operate. One example is the special tile in strategic locations that protects the space shuttle (1980s) from high temperatures on reentry . After an exotic zirconium composite material was tried, the final tile design used silica fibers derived from common sand.