NOVELTY - The system comprises pyrolytic plasma reactor apparatus (10) including carbonaceous material and nozzles (14) with plasma torches, an inlet (18) for torch gas to the plasma torches at locations to generate plasma gas directed into a first portion of the carbonaceous material, an inlet for process material comprising hydrocarbon material to the plasma gas produced in the torches, an inlet for fluid comprising steam to the plasma gas to form a mixture with the process material, the first portion of carbonaceous material, the nozzles including the plasma gas, and additional nozzles (16).    USE - The system is useful for converting heavy hydrocarbon material such as heavy oils present in the form of oil in tar sand, oil in oil shale and oil residuals to lighter hydrocarbon material with carbon monoxide and hydrogen.    ADVANTAGE - The system is capable of effectively and easily converting the heavy hydrocarbon compounds to lighter hydrocarbon compounds without necessitating expensive catalysts and high pressure reactors.    DETAILED DESCRIPTION - The system comprises pyrolytic plasma reactor apparatus (10) including carbonaceous material and nozzles (14) with plasma torches, an inlet (18) for torch gas to the plasma torches at locations to generate plasma gas directed into a first portion of the carbonaceous material, an inlet for process material comprising hydrocarbon material to the plasma gas produced in the torches, an inlet for fluid comprising steam to the plasma gas to form a mixture with the process material, the first portion of carbonaceous material, the nozzles including the plasma gas, additional nozzles (16) located to inject additional material into a second portion of the carbonaceous material at a location to which the initial products flow, an inlet for additional process material comprising hydrocarbon material and an inlet for additional fluid comprising steam to the additional nozzles and into the second portion of carbonaceous material, and an exit port from the reactor apparatus for lighter weight hydrocarbon material and gases. The inlets for the process material and the steam fluid are arranged for reaction of the hydrocarbon process material with the carbonaceous material and steam fluid to form initial products including lighter weight hydrocarbon material, carbon, carbon monoxide and hydrogen. The second portion of the carbonaceous material and the additional nozzles including the inlets for additional process material and steam fluid are arranged for reactions including some carbon monoxide of the initial products reacting with steam to form carbon dioxide and hydrogen and some of the hydrogen so produced reacting with the additional process material to form additional lighter weight hydrocarbon material. The first and second portions of carbonaceous material are both contained in a single reactor vessel with the second portion located above the first portion. The first and second portions of carbonaceous material are respectively contained in a first and a second reactor vessel with a conduit for fluid to flow from the first to the second vessel. The nozzles to inject additional material into the second portion of the bed are without plasma torches. The plasma torches include ionizing electrodes for heating the torch gas to produce a temperature of 1600 degrees C in the bed. The inlet for process material comprising hydrocarbon material is connected with a supply containing heavy oils, oil in tar sand, oil in oil shale, and oil residuals. The inlets for process material and for steam fluid to the plasma gas are each directly within the nozzles with the plasma torches, and a first and second combined inlet for a mixture of process material and steam fluid. The reactor apparatus includes, above the second portion of carbonaceous material, an inlet for a moderating gas to reduce the temperature of reaction products rising from the bed. The inlet for moderating gas is connected with a supply of moderating gas introduced into the reactor apparatus to maintain a region above the bed at a temperature below 450 degrees C. The moderating gas comprises a member of steam, carbon dioxide and/or plant recycle gas. An INDEPENDENT CLAIM is included for a system for upgrading heavy hydrocarbon compounds to produce relatively lighter hydrocarbon compounds.    DESCRIPTION OF DRAWING(S) - The figure shows an elevational sectional view of a system including a plasma cupola.    Plasma reactor apparatus (10)    Carbonaceous bed (12)    Torch nozzles (14)    Additional nozzles (16)    Inlet (18)    Freeboard region. (20)