Method of thermally cracking heavy petroleum oil

Claim 1

In a method of thermally cracking a heavy petroleum oil by heating said heavy petroleum oil to a temperature of 450° to 520° C. in a first furnace and introducing the thus heated heavy petroleum oil into a reactor wherein said heated heavy petroleum oil is brought into contact with an unreactive gas at a temperature of 400° to 2,000° C., thereby thermally cracking said heated heavy petroleum oil at a reaction temperature of 400° to 440° C., the improvement comprising: (a) using two or more of said reactors; (b) heating a portion of said heavy petroleum oil to a temperature of 300° to 350° C. in a second furnace; (c) precharging alternatively each reactor with the heated oil from step (b), said portion of oil in step (b) corresponding to 3 to 30% by weight of said heavy petroleum oil to be thermally cracked within said reactor, prior to the introduction of said heated heavy petroleum oil at a temperature of 450° to 520° C., and keeping the thus precharged heavy petroleum oil at a temperature of 300° to 350° C. within said reactor; and (d) alternatively feeding said heated heavy petroleum at a temperature of 450° to 520° C. from said first furnace into said reactors containing said precharged portion of said heavy petroleum oil kept at a temperature of 300° to 350° C., and switching the feed from the first reactor to the second reactor when the introduction of said heated heavy petroleum oil at a temperature of 450° to 520° C. into said first reactor is completed, whereby the formation of coke as a byproduct and the rupture of the reactor as a result of a radical temperature rise are prevented.