Han Shu, compiled by Ban Gu, a famous historian in the Eastern Han Dynasty (32-92 AD), records: "When there is water in a high slave, it is natural." Gao Nu is in Yanchang County, Shaanxi Province today. W ě water is a tributary of Yanhe River. "Ran" is the word "burn" in ancient times. That is to say, as early as China 1 century ago, it was found that there was oil on the water surface, which could be burned.
But for a long time, whether in China or other ancient civilizations, after the discovery of oil, it was only directly used as fuel or lighting, emitting thick black smoke and producing a strong pungent smell.
It was not until the beginning of19th century that people began to realize that kerosene distilled from petroleum can be used as fuel and lighting, which can reduce black smoke and unpleasant smell. 1823, Russian farmer B. Dubinin and his two brothers first built a device for distilling oil near Grozny, which is rich in oil in the North Caucasus, to extract kerosene.
From 65438 to 0855, by analyzing the chemical composition of petroleum, Hilliman, a professor of chemistry at Yale University in the United States, determined that petroleum was a mixture of various hydrocarbons, and began to distill petroleum to obtain 50% products similar to coal tar for lighting. 1859, Drake first drilled oil in Titusville, Pennsylvania, USA. It no longer waits for oil to slowly gather on the ground to collect. At that time, oil was used as a surgical agent. Treat all diseases. It was only after a while that Kiel, an oil seller in Pittsburgh, USA, accepted the advice of a chemist and fractionated oil by fractionating wine and water. At first, only hydrocarbon naphtha containing 5~8 carbon atoms, namely solvent oil and gasoline, was obtained. Later, kerosene containing 9~ 18 carbon atoms was fractionated, and the remaining fraction was lubricating oil, which was used as lubricant, and the remaining asphalt was used to coat the roof for leakage prevention. Diesel oil, lubricating oil and vaseline are gradually fractionated from lubricating oil, and kerosene is decolorized and deodorized with sulfuric acid and alkali for lighting. This is probably the end of 19.
It is the first time that kerosene is extracted from oil for lighting.
At this time, gasoline has not been fully utilized because it has a low ignition point and is easy to volatilize. Not only will it catch fire, but it will also burn into pieces and even explode. So people at that time regarded it as a dangerous "waste" and didn't know how to deal with it.
By the end of 19, internal combustion engines and automobiles came out one after another. Internal combustion engines are different from steam engines. A steam engine uses fuel to boil water in a boiler to produce steam, and then introduces the steam into a cylinder to drive a piston to do work. The internal combustion engine introduces fuel into the cylinder for combustion, so that the gas produced by combustion drives the piston to do work. The internal combustion engine needs combustible liquid as fuel, and gasoline just meets its requirements. When the internal combustion engine was installed on the car and became a car, the car developed rapidly, and then planes and motorboats appeared one after another, and gasoline turned "waste" into treasure.
This is the second discovery of the use of oil.
After the appearance of electric light, the demand for kerosene was greatly reduced. This in turn urges people to study as soon as possible whether more gasoline can be extracted from petroleum and the production of kerosene can be reduced.
Chemists and engineers imagine that since gasoline is a hydrocarbon with fewer carbon atoms and kerosene is a hydrocarbon with more carbon atoms, is it possible to decompose more carbon atoms into fewer carbon atoms?
By the beginning of the 20th century, this idea began to come true. Burton, a chemist at Standard Oil Company, started his research at 19 10. 19 13 patent. He put the oil in a pot and heated it, so that the kerosene broke into smaller molecules under a certain pressure, and the kerosene became gasoline. Now this process is called pyrolysis. It turns out that 10 ton of oil can only get about 1 ton of gasoline. After the cracking method was adopted, the gasoline output increased.
The process of cracking hydrocarbons containing more carbon atoms in petroleum into hydrocarbons containing less carbon atoms is a chemical processing process of petroleum, which is different from petroleum fractionation, which is a physical processing process of petroleum.
With the rapid development of automobiles and airplanes, large passenger planes and supersonic jets have appeared, and the demand for gasoline is increasing. It is necessary not only to crack kerosene into gasoline, but also to extract more gasoline from the whole oil, and at the same time, it puts forward higher requirements for the quality of gasoline.
When the mixture of gasoline vapor and air burns in the cylinder of internal combustion engine, it often explodes before ignition, thus causing knocking. This not only wastes energy, but also damages the cylinder of internal combustion engine. According to the experiments of chemists, the degree of deflagration is related to the composition of gasoline used. Generally speaking, straight-chain alkanes have the highest degree of detonation when burning, while alkanes with more cyclic hydrocarbons and branched chains have the lowest degree of detonation. Among the gasoline components containing 7~8 carbon atoms, n-heptane has the greatest knock degree, while isooctane basically does not knock. The molecular structure of n-heptane is linear and isooctane is branched.
Therefore, the octane number is set as the scale of gasoline deflagration, based on the octane numbers of n-heptane and isooctane, the octane number of n-heptane is 0 and that of isooctane is 100. In the mixture of n-heptane and isooctane, the mass fraction of isooctane is called the octane number of this mixture, which is also commonly known as what number gasoline.
The octane number of all kinds of gasoline, or the number of gasoline, is obtained by comparing them with the knocking phenomenon when the above mixture is burned. For example, the octane number of a gasoline is 80, or 80 # gasoline, that is to say, when this gasoline is burned in a standard single cylinder, the knocking phenomenon is the same as that when 20% (volume fraction) of n-heptane and 80% of isooctane are burned in the same cylinder. Ordinary gasoline is not a simple mixture of n-heptane and isooctane, so the octane number only indicates the knock degree of gasoline, not the content of isooctane.
Shortly after the First World War, the laboratory of General Gasoline Company of the United States screened many substances, trying to find a substance and add it to gasoline to reduce the combustion knock of gasoline. Finally, the compound of tetraethyl lead Pb(C2H5)4 was found in192165438+February 9th. It is said that the experimenters at that time danced with joy.
Tetraethyl lead is a colorless and toxic liquid with a strong smell, which can really reduce the knock after adding a small amount of gasoline, so it is called an anti-seismic agent. However, it was later found that tetraethyl lead would generate lead oxide after burning in the cylinder, which accumulated in the cylinder and caused obstacles. Then dibromoethane (CH2)2Br2 and dichloroethane (CH2)2Cl2 are added. They can react with tetraethyl lead during combustion and discharge the generated substances together.
There is another way to solve the knock problem caused by gasoline combustion in the cylinder. In the 1920s, Houdry, a French mechanical engineer, created a chemical treatment method for petroleum cracking.
The by-products of cracking and cracking are mainly ethylene, propylene, methane, ethane and propane. They are raw materials for making plastics such as polyethylene, polyvinyl chloride and polypropylene, as well as artificial fibers, artificial rubber, washing powder and pesticides. They became chemical raw materials.
This is the third discovery of the use of oil.