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Non-Venture Oil Question


1sttenor

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Cracking:

For heavy crude, but also for the heavier fractions of the light crude (since in both cases we would like to end up with about 45% gasoline), requires that we crack (or split) the higher carbon molecules into lighter or lower carbon ones. For example say we have a molecule of Cetane (16 carbon & 34 hydrogen atoms or C16H34) if we heat this to a high enough temperature, then we can break it down into some Octane (C8H18), some Hexane (C6H12) and some Ethylene (C2H4). But, obviously, what we would like to do is to control what it is that we break these heavier molecules into, and how much of each we produce.

 

 

And so we get into the world of cracking oil. After the crude oil has been separated into the different fractions, the gas-oil fraction is then fed to a second heating process, where the fluid is brought back up to a high temperature (perhaps around 735 deg C 1400 deg F) and mixed with a finely powdered catalyst (hence the "cat"). Steam is also added to help with the movement of the mix, and the combined mix is fed up a pipe (called a riser) into a tank and as it flows up and into the tank the gas-oil breaks down into the lower carbon molecules. This happens very quickly, so that by the time the mix is in the tank, the heavy molecules have broken down, and so can be drawn off. However the catalyst has first to be removed, which happens by passing the flow through cyclones that spins the flow and separates the heavy catalyst, which is collected and fed down a pipe back to be reclaimed and re-used. It needs to be processed since, in part, the process is not perfect and carbon will be deposited on the particles of catalyst, blocking its action. (It can be burned off - providing some of the heat for the process). The catalyst can then be re-used. One operation might use the catalyst at a flow rate of some 55 tons/minute.

 

 

The hydrocarbons that flow out of the cracking process are then separated into different fractions, depending on the season more gasoline or distillate might be desired, but the process might yield about 8% coke, 55% gasoline, and 12% light gas oil with about 10% of the flow being a sufficiently heavy product that it is sent back to be run through the process again. Light gas oil becomes diesel and furnace fuel oil. The lighter gas products are usually sent to alkylation or reforming, where the lighter molecules can be combined to give products that can be blended into gasoline.

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Cracking:

For heavy crude, but also for the heavier fractions of the light crude (since in both cases we would like to end up with about 45% gasoline), requires that we crack (or split) the higher carbon molecules into lighter or lower carbon ones. For example say we have a molecule of Cetane (16 carbon & 34 hydrogen atoms or C16H34) if we heat this to a high enough temperature, then we can break it down into some Octane (C8H18), some Hexane (C6H12) and some Ethylene (C2H4). But, obviously, what we would like to do is to control what it is that we break these heavier molecules into, and how much of each we produce.

 

 

And so we get into the world of cracking oil. After the crude oil has been separated into the different fractions, the gas-oil fraction is then fed to a second heating process, where the fluid is brought back up to a high temperature (perhaps around 735 deg C 1400 deg F) and mixed with a finely powdered catalyst (hence the "cat"). Steam is also added to help with the movement of the mix, and the combined mix is fed up a pipe (called a riser) into a tank and as it flows up and into the tank the gas-oil breaks down into the lower carbon molecules. This happens very quickly, so that by the time the mix is in the tank, the heavy molecules have broken down, and so can be drawn off. However the catalyst has first to be removed, which happens by passing the flow through cyclones that spins the flow and separates the heavy catalyst, which is collected and fed down a pipe back to be reclaimed and re-used. It needs to be processed since, in part, the process is not perfect and carbon will be deposited on the particles of catalyst, blocking its action. (It can be burned off - providing some of the heat for the process). The catalyst can then be re-used. One operation might use the catalyst at a flow rate of some 55 tons/minute.

 

 

The hydrocarbons that flow out of the cracking process are then separated into different fractions, depending on the season more gasoline or distillate might be desired, but the process might yield about 8% coke, 55% gasoline, and 12% light gas oil with about 10% of the flow being a sufficiently heavy product that it is sent back to be run through the process again. Light gas oil becomes diesel and furnace fuel oil. The lighter gas products are usually sent to alkylation or reforming, where the lighter molecules can be combined to give products that can be blended into gasoline.

 

Very interesting. Are you in this field?

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