Presentation on theme: "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."— Presentation transcript:
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. 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 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. I. ENERGY AND TRANSPOTATION I.1. Energy sources Charles Parsons Parsons’ Steam turbine (1907)
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. 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. Carbon-zinc dry battery Rechargeable batteries
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 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.