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This article needs additional citations for verification. Crack No Steam Portal 2 help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of a large alkane into smaller, more useful alkanes and alkenes. Simply put, hydrocarbon cracking is the process of breaking a long-chain of hydrocarbons into short ones.
This process might require high temperatures and high pressure. More loosely, outside the field of petroleum chemistry, the term «cracking» is used to describe any type of splitting of molecules under the influence of heat, catalysts and solvents, such as in processes of destructive distillation or pyrolysis. Fluid catalytic cracking produces a high yield of petrol and LPG, while hydrocracking is a major source of jet fuel, Diesel fuel, naphtha, and again yields LPG. Refinery using the Shukhov cracking process, Baku, Soviet Union, 1934.
One installation was used to a limited extent in Russia, but development was not followed up. In the first decade of the 20th century the American engineers William Merriam Burton and Robert E. Humphreys independently developed and patented a similar process as U. 1,049,667 on June 8, 1908.
Among its advantages was the fact that both the condenser and the boiler were continuously kept under pressure. In its earlier versions however, it was a batch process, rather than continuous, and many patents were to follow in the USA and Europe, though not all were practical. In 1924, a delegation from the American Sinclair Oil Corporation visited Shukhov.
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Sinclair Oil apparently wished to no that the patent of Burton and Humphreys, in use by Standard Oil, was derived from Shukhov’s patent for oil cracking, as described crack the Russian portal. If that could be established, it could strengthen the hand of rival American companies wishing to invalidate steam Burton-2 patent.
In the event Shukhov satisfied the Americans that in principle Burton’s method closely resembled his 1891 patents, though his own interest in the matter was primarily to establish that «the Russian oil industry could easily build a cracking apparatus according to any of the described systems without being accused by the Americans of borrowing for free». At that time, just a few years after the Russian Revolution, Russia was desperate to develop industry and earn foreign exchange, so their oil industry eventually did obtain much of their technology from foreign companies, largely American. At about that time however, fluid catalytic cracking was being explored and developed and soon replaced most of the purely thermal cracking processes in the fossil fuel processing industry. Thermal cracking remains important however, for example in producing naphtha, gas oil, and coke, and more sophisticated forms of thermal cracking have been developed for various purposes.
These include visbreaking, steam cracking, and coking. This section does not cite any sources.
Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. A large number of chemical reactions take place during the cracking process, most of them based crack No Steam Portal 2 free radicals. Computer simulations aimed at modeling what takes place during steam cracking have included hundreds or even thousands of reactions in their models.
In these reactions a single molecule breaks apart into two free radicals. Only a small fraction of the feed molecules actually undergo initiation, but these reactions are necessary to produce the free radicals that drive the rest of the reactions.
In steam cracking, initiation usually involves breaking a chemical bond between two carbon atoms, rather than the bond between a carbon and a hydrogen atom. In these reactions a free radical removes a hydrogen atom from another molecule, turning the second molecule into a free radical.
In these reactions a free radical breaks apart into two molecules, one an alkene, the other a free radical. This is the process that results in alkene products. In these reactions, the reverse of radical decomposition reactions, a radical reacts with an alkene to form a single, larger free radical. These processes are involved in forming the aromatic products that result when heavier feedstocks are used.
In these reactions two free radicals react with each other to produce products that are not free radicals. Two common forms of termination are recombination, where the two radicals combine to form one larger molecule, and disproportionation, where one radical transfers a hydrogen atom to the other, giving an alkene and an alkane. You can help by adding to it. Thermal cracking was the first category of hydrocarbon cracking to be developed.
An overall process of disproportionation can be observed, where «light», hydrogen-rich products are formed at the expense of heavier molecules which condense and are depleted of hydrogen. The actual reaction is known as homolytic fission and produces alkenes, which are the basis for the economically important production of polymers. Shortly thereafter, in 1921, C. The Dubbs process was used extensively by many refineries until the early 1940s when catalytic cracking came into use.