Oil refining process. Schematic diagram of how oil is refined from the crude state to the finished products. The process depends on breaking down the oil in a process named catalytic cracking (at 500 degrees Celsius). The three main areas here are (left to right): catalyst regeneration; cracking tower; and the fractionating tower. Air (blue) is supplied to regenerate the catalyst. Crude oil (grey) is pumped into the cracking tower. The product ends up in the fractionating tower (right). Different components of the crude oil condense at different temperatures, and hence at different heights. The products (bottom to top) are: bitumen, fuel oil, diesel oil, kerosene, naptha, petrol and gas.