I understand from the diagram below that different fuels condense at different temperatures. But I don't know anything about crude oil (and very little about chemistry in general). Could I simply refine 100% of crude oil to gasoline by heating it up to 150 °C (value taken from diagram).

Put another way, are the ratios of end products from refining crude oil fixed?

Crude Oil Distillation

  • $\begingroup$ Sorry, are you asking if: if you had a gallon of crude and let it sit and simmer at 150 degrees, would you wind up with a gallon of gasoline eventually? Because I'm not clear on what you're asking, but that is emphatically not how fractional distillation works. $\endgroup$ – Broklynite Apr 1 '16 at 23:19
  • $\begingroup$ Thank you, your comment was helpful. I was wondering whether I can only produce gasoline from crude oil. No Diesel, no kerosene, nothing else. Or is there a fixed relationship, e.g., 1 gallon of crude results in 0.x gallons of gasoline, 0.x gallons of Diesel, and so on. $\endgroup$ – lexeter Apr 2 '16 at 15:53
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    $\begingroup$ You never get 100% pure anything from fractional distillation. $\endgroup$ – Broklynite Apr 2 '16 at 20:39

Crude oil is a complicated mixture consisting of a variety of different hydrocarbons and the particular composition is very variable depending on where it is found.

Distillation is merely a means of separating those components so it can do nothing to create more of one of them. And gasoline is, essentially, just a mixture of those components with similar properties and boiling points. There is little you can do by distillation to create more gasoline.

However refiners do have access to chemical means to alter the composition. Catalytic cracking, for example, converts constituents into different chemicals and this can allow a refinery to create more gasoline or diesel by breaking down the higher-boiling components into smaller parts. But this is much more complicated than distillation.

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I see where you are coming from but I don't think you can simply get gasoline by heating crude oil to 150°C. There are few more important steps that should be taken before putting crude oil into the furnace. Have a look. (Picture taken from Wikipedia)

Fractional Distillation

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  • $\begingroup$ Thank you for your answer. I was aiming at a different aspect, though. I was wondering whether distillation of crude oil always yields the same ratios of fuel or if that ratio can be influenced. E.g., you'll always end up with 20% gasoline, 20% Diesel, and so on. (I know very little about chemistry and just randomly picked numbers here.) $\endgroup$ – lexeter Apr 14 '16 at 11:53

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