Heavy oil is heated in preheated to a temperature of about 425-4500C. the resulting vapours oil is charge is then forced through the catalytic chamber.
The catalytic chamber is maintained at a temperature of 425-4500C and 1-5 kg/cm2 pressure. Artificial clay mixed with zirconium oxide is used as a catalyst.
About 40% of the charge is converted to gasoline and 2-4 is deposited over the catalyst bed as carbon.
The vapours containing heavy oil as well as cracked gasoline pass into the fractionating column where heavy oil condenses.
The uncondensed vapour containing the cracked fraction is led to the coolers where some of the vapour condense to form uncondensed gases dissolved in gasoline.
Gasoline containing dissolved gases is then sent through stabilizer where dissolved gases are removed and pure gasoline is obtained.
After 8-10 hours of operation, the catalyst gets deactivated and has to be reactivated the catalyst tower is heated to about 5000C whereby the carbon deposited burns reactivating the catalyst.
The process can be converted to a continues one by having catalyst towers. While the first tower in operation the second tower is being regenerated and vice-versa.