More specifically, at an oil refinery, the stuff that is the most volatile comes out on top, eg gases and gasoline. And the least volatile stuff, with the most complex hydrocarbon chains, becomes the residue, and bitumen is one of the residues. I think that's what it is, it's been a loooong time since I learned about it in school.
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I would give your icons hugs if I wasn't afraid of dying when getting too near to him! *ditz*
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XD You might be pricked to death by teh needles!
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