Process for thermal cracking of heavy oil

A process for the thermal cracking of heavy oils having a Conradson carbon residue, CCR value greater than 3, which comprises:

• thermal cracking a heavy oil by contacting said heavy oil with a fluidized bed of fine, porous particles having a pore volume of 0.2 to 1.5 cm.sup.3 /g, a specific surface area of 5 to 1500 m.sup.2 /g, an average pore size of 10 to 10,000 .ANG., a weight average size of 0.025 to 0.25 mm at an elevated temperature sufficient to thermally crack said oil, and said particles having heavy metal deposited thereon, which is obtained from the heavy oil which inherently contains heavy metal, in an amount of at least 0.5% by weight, said bed being fluidized with a hydrogen containing gas at a velocity such that the partial pressure of hydrogen ranges from about 0.5 to about 5 kg/cm.sup.2 while the total pressure in said cracking step ranges from about 1 to about 10 kg/cm.sup.2 -G, thereby producing a light oil product having a boiling point which is lower than the heavy oil feed without substantial consumption of the hydrogen gas being used while reducing the amount of coke which forms during thermal cracking;
• and
• regenerating fine, porous particles withdrawn from said thermal cracking step which have coke adhered thereto by fluidizing said coked particles with a molecular oxygen-containing gas and a steam-containing gas and recirculating said regenerated particles to said thermal cracking step.