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Gasoline, mixture of the lighter liquid hydrocarbons used chiefly as a fuel for internal-combustion engines. It is produced by the fractional distillation of petroleum; by condensation or adsorption from natural gas; by thermal or catalytic decomposition of petroleum or its fractions; by the hydrogenation of producer gas or coal; or by the polymerization of hydrocarbons of lower molecular weight. Internal-Combustion Engine.
Gasoline produced by the direct distillation of crude petroleum is known as straight-run gasoline. It is usually distilled continuously in a bubble tower (Distillation), which separates the gasoline from the other fractions of the oil having higher boiling points, such as kerosene, fuel oil, lubricating oil, and grease. The range of temperatures in which gasoline boils and is distilled off is roughly between 38° and 205° C (100° and 400° F). The yield of gasoline from this process varies from about 1 percent to about 50 percent, depending on the petroleum. Straight-run gasoline now makes up only a small part of U.S. gasoline production because of the superior merits of the various cracking processes.
In many parts of the country natural gas contains a percentage of natural gasoline that may be recovered by condensation or adsorption. The most common process for the extraction of natural gasoline includes passing the gas as it comes from the well through a series of towers containing a light oil called straw oil. The oil absorbs the gasoline, which is then distilled off. Other processes involve adsorption of the gasoline on activated alumina, activated carbon, or silica gel.
High-grade gasoline can be produced by a process known as hydrofining, that is, the hydrogenation of refined petroleum oils under high pressure in the presence of a catalyst such as molybdenum oxide. Hydrofining not only converts oils of low value into gasoline of higher value but also at the same time purifies the gasoline chemically by removing undesirable elements such as sulfur. Producer gas, coal, and coal-tar distillates can also be hydrogenated to form gasoline. Hydrogenation.
For use in high-compression engines, it is desirable to produce gasoline that will burn evenly and completely in order to prevent knocking, the sound and damage caused by premature ignition of a part of the fuel and air charge in the combustion chamber of an internal-combustion engine. The antiknock characteristics of a gasoline are directly related to its efficiency and are indicated by its octane number. This is a rating that describes performance of a fuel in comparison with that of a standard fuel containing given percentages of isooctane and heptane. If the performance of the rated fuel is the same as that of a standard fuel with a certain percentage of isooctane, the octane number given the rated fuel is the same as the percentage of isooctane in the standard fuel. The higher this number, the less likely a fuel is to cause knocking. Cracked gasoline has better antiknock characteristics than straight-run gasoline, and any gasoline can be further improved by the addition of such substances as tetraethyl or tetramethyl lead. Since it was discovered, however, that the emission of lead from gasolines combined with such additives is dangerous to living beings—among other effects, raising blood pressure—research on new ways to reduce the knocking characteristics of gasoline was intensified.
Low-lead gasolines were introduced in the early 1970s as a result of increased public concern about air pollution. After 1975 all new automobiles in the U.S. were equipped with catalytic converters to reduce the engine's emission of pollutants. Because even low-lead gasoline “poisons” the catalyst, the proportion of leaded gasoline in the U.S. declined from 73 percent of the total supply in 1976 to less than 10 percent in 1990. (European countries were moving more slowly in this same direction.) The Clean Air Act of 1990 required oil companies to make available cleaner gasoline with a higher oxygen content in polluted urban areas, beginning in 1992. In the late 1990s many environmentalists called for the increased use of gasohol and cleaner-burning natural gas. In addition, in 1999 and 2000 two Japanese automakers introduced hybrid electric-gas vehicles to the U.S. market that greatly increased fuel efficiency and lowered emissions of air pollutants. Several U.S. automakers also began intensive work on vehicles powered by fuel cells that used no gasoline at all. In 2003 President George W. Bush called for the development of a fuel-cell car by 2019. Electric Car; Fuel Cell.
chewy wrote:this brings up another interesting question, which is how much of the energy spent in burning in bio-feul is actually transfered to powering the vehicle and how much is wasted in the form of heat? I would imagine these feuls are no better than gasoline in this respect (combustion engines waste a lot of this energy).
Rich wrote:Bill: Where did you get this info? It looks way too high.
Rudolf Diesel shocked reputable scientists and inventors at the 1900 World's Fair in Paris by pouring peanut oil directly into his newly unveiled diesel engine. While at the time revolutionary, no idea could have been more natural for an innovator who had spent his childhood in the agricultural provinces of France and Germany. Throughout his career, Diesel promoted the benefits of agricultural fuel. In a speech given in Germany in 1911, he declared, "The diesel engine can be fed with vegetable oils and would help considerably in the development of agriculture of the countries which use it."
Two years later, Diesel was on a trip across the English Channel when he disappeared. Mysteriously, his body was never found. The English newspapers suggested that he had been assassinated by foreign agents.
After Diesel's death, the idea of fueling engines with vegetable oil was quickly and quietly swept under the rug. His original designs were modified and diesel engines were made to run on the cheapest, most abundant fuel available: petroleum.
Biodiesel is easily made from vegetable oil, alcohol and a catalyst, through a process called transistorification. The only by-product is glycerin, which can be used to make soap or any one of thousands of other products. Biodiesel can be used in any diesel engine and burns 75% cleaner than petroleum diesel fuel. It can be made from any vegetable oil, including soy, canola, sunflower, hemp, coconut and even used cooking oils or animal fat. It is highly lubricating, which actually makes it better for diesel engines than diesel fuel. But the best thing about biodiesel is that it requires absolutely no engine modifications. To use it, you just pour it into the fuel tank. It even mixes with regular petroleum diesel fuel.
But the best thing about biodiesel is that it requires absolutely no engine modifications. To use it, you just pour it into the fuel tank.
In the 1998 study at the Southwest Research Institute on Biodiesel effects on diesel engine performance, engine power in the 1997 Cummings truck engine operating on the B-20 blend was at 98.5% of the power attained with low sulfur No. 2 diesel. At 100% Biodiesel, the engine generated 92% of the power. For a Detroit Diesel truck engine (1997), the power was 98% with the B-20 and 92% with the neat Biodiesel.
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