Thanks for answering.
I've found some pretty good websites. Wikipedia and references where would we be without them!
I'm very sure I understand the refining process now. Chemically it's very complex!
Basically oil goes in chamber. Chamber boils different hydrocarbons off. Jet fuel is collected. Jet fuel is put through merox treatment. Merox catalyst removes mercaptan sulfur. Refined jet fuel is collected.
VERY basically put, but I hope that's right.