Abstract: Synthesis gas is produced by the partial oxidation of a high silicon and sulfur-containing heavy liquid hydrocarbonaceous fuel and/or petroleum coke having a nickel and vanadium-containing ash that includes calcium and sodium, in a mixture with an iron and/or copper containing additive in a vertical free-flow reaction zone lined with refractory A or a combination of refractory A and refractory B. Refractory A lining of the reaction zone comprises in wt %: Cr.sub.2 O.sub.3 about 20 to 82, MgO about 5.0 to 45, Fe.sub.2 O.sub.3 about 0 to 10.5 Al.sub.2 O.sub.3 about 0 to 6.2, CaO about 0 to 1.0, SiO.sub.2 about 0 to 2.5, and others about 0 to 1.3. Refractory B comprises in wt. %: Cr.sub.2 O.sub.3 about 0 to 40, MgO about 20 to 85, Fe.sub.2 O.sub.3 about 0 to 16, Al.sub.2 O.sub.3 about 0 to 9.0, SiO.sub.2 about 0 to 2.7, and others about 0 to 1.1.

Abstract: Synthesis gas is produced by the partial oxidation of a feedstock comprising petroleum coke containing metal sulfide compounds and metal oxy-sulfide compounds and having an ash that contains nickel, vanadium and silicon. In the process, a petroleum coke addition agent, such as elemental iron and/or iron compounds, is introduced into the upper section of a delayed coker and above the level of the nickel and vanadium ash-containing heavy liquid hydrocarbonaceous fuel being simultaneously introduced upwardly from the bottom of said delayed coker. By this means the petroleum coke addition agent is distributed uniformly across the surface of liquid hydrocarbonaceous material being coked and then uniformly distributed throughout the liquid fuel. In the delayed coker, a portion of the petroleum coke addition agent is reacted with a portion of the sulfur in the heavy liquid hydrocarbonaceous fuel to produce metal oxy-sulfides and metal sulfides.