Process, reactor and facility for thermally cracking heavy petroleum oil

A reaction vessel used in a method for thermal cracking processing of heavy petroleum oil including:

• blowing superheated steam of 400 to 700° C., from a bottom portion of the reaction vessel, into the heavy petroleum oil having been heated to 450° C. or higher in a heating furnace and thereafter introduced into the reaction vessel of which at least a shell has a cylindrical shape;
• bringing the superheated steam into direct contact with the heavy petroleum oil to be thermally cracked into an oil fraction and a pitch;
• and discharging the oil fraction successively from a top of the reaction vessel together with the superheated steam and removing the pitch from the reaction vessel collectively after the completion of the thermal cracking, comprising
• a steam-blowing means, by which, in blowing the superheated steam from the bottom portion of the reaction vessel, the blowing is carried out so that the superheated steam generates a rotational flow around the central axis of the shell inside of the reaction vessel, wherein:
• the steam-blowing means comprises means for blowing the superheated steam into the reaction vessel from one or two or more tubular blowing nozzles which are provided to the bottom portion of the reaction vessel and are opened to the inside of the reaction vessel through blowing orifices;
• and
• the blowing nozzles are directed so as to be parallel or upward against a plane which is perpendicular to the axis of the shell of the reaction vessel and includes the blowing orifices, and to have a facing angle θ between the blowing and the normal line on the plane to the outer wall of the reaction vessel of 20° or more and 60° or less.