Abstract: Disclosed is a method for the thermal cracking of a heavy petroleum oil to produce a pitch with a high aromaticity having a high softening point, the ratio of H/C of about 0.4 to 1.1 and the fraction insoluble in n-heptane but soluble in quinoline of higher than 55% by weight and an oil mainly composed of aliphatic hydrocarbon by feeding the heavy petroleum oil into a reaction system and bringing it therein into contact with a gas which does not react with the heavy petroleum oil, of a temperature in the range of from 400.degree. C. to 2000.degree. C., which method is improved by using, as the reaction system, a plurality of reaction vessels arranged in series and having their interior temperatures successively lower by a fixed step in the direction of the transfer of the charge.

Abstract: The mass production system disclosed herein provides a method for producing highly aromatic petroleum pitch, comprising, preheating a liquefied petroleum residuum to a temperature of 450.degree.-520.degree. C. by passing the same through a tubular heater for 0.5-15 minutes, feeding the preheated residuum into a reaction vessel, thermally cracking the same by introducing an inert gas heated to a temperature of 400.degree.-2,000.degree. C. through a heating furnace into the reaction vessel for direct contact with the residuum for 0.5-10 hours, and adjusting to be coincident the ratio of the number of feeding flow lines for the preheated residuum from the tubular heater into the reaction vessels to the total number of reaction vessels with the ratio of the charging time .theta.C required for charging one reaction vessel with one feeding flow of preheated residuum to the total time .theta.T required for carrying out one batch of the thermal cracking in one reaction vessel.

Abstract: Disclosed herein is a method of thermally cracking a heavy petroleum oil by introducing the heavy petroleum oil into a reactor and contacting the heavy petroleum oil thus introduced with a gas, which does not react with the heavy petroleum oil, at a temperature of 400.degree.-2000.degree. C. thereby thermally cracking the heavy petroleum oil. The method uses plural reactors and introduces the heavy petroleum oil into the reactors in a specified manner, and charges the reactor in advance with a specified amount of heavy petroleum oil of a specified temperature.

Abstract: High grade cokes are produced by a simple expedient such that a raw material oil is charged into a coking drum and is subjected therein to a two step operation, namely reforming of the oil and subsequent coking under bubbling into the oil of a heated non-oxidizing gas. No fluidized bed of the oil to be coked is formed.