[peterjlee]

Is the refining process flexible enough to do that? I was under the impression that refining is more of a separation process so the amount of each petroleum product you get is already determined by the petroleum you have before you even start the process.

[maxerickson]

There's all sorts of processes used to convert stuff.

https://en.wikipedia.org/wiki/Cracking_(chemistry)

[hx87]

You can crack the fuel to go from heavier to lighter grade, and use Fischer-Tropsch process to go the other way.