NOVELTY - Process (P') for converting a feed composition comprising at least one material decomposable into hydrocarbon material, in a ribbonchannel reactor (122) that comprises a first heated cylindrical surface (124) and a second heated cylindrical surface (126) spaced away from the first surface, to a hydrocarbon material; involves: flowing feed composition in reactor; rotating first surface relative to second surface; forming a substantially spiral ribbon comprising feed composition between first and second surfaces; and heating ribbon to generate a vapor comprising the hydrocarbon material.    USE - For converting a feed composition comprising at least one material decomposable into hydrocarbon material (claimed), useful for converting hydrocarbon-formable materials, such as plastics and other waste or other recycled materials including used lubricants including motor oil, gear oil and waste glycerin from biodiesel; and rubber and high molecular weight material; into fuel e.g. a motor oil base stock, lubricants and products of other end uses.    ADVANTAGE - The process provides an improved process for converting hydrocarbon-formable materials, such as plastics and other waste or other recycled materials, into fuel; which is a highly efficient, economical, and relatively simple process; by utilizing a ribbonchannel reactor. The ribbonchannel reactor provides a unique device. By virtue of the substantially concentric mounting of two closely sized hollow cylinders and several continuous low height helical flighting disposed between the cylinders, a ribbonchannel is defined in which a relatively thin ribbon of the feed composition is formed. Heat is uniformly applied to relatively thin ribbon from major two sides or faces and feed is quickly and efficiently decomposed thermally to form hydrocarbons. Thus, the ribbonchannel has the capability to provide two-sided heating to the ribbon of feed composition in the ribbonchannel. Two-sided heating provides at least twice the heating capability, in terms of rate and efficiency of heat transfer, than than obtained from either single-side heating or heating applied to a greater thickness of the feed composition than the thicknesses for the ribbonchannel. The ribbonchannel reactor provides a high ratio of heated surface area to the volume of feed material of 4:1-1:2. The unique combination of of cylinders and low height helical flighting simultaneously transports the input feed composition, while very rapidly provides to it the heat for decomposition of the feed composition to form hydrocarbon materials. As a result of the low height flighting used in the ribbonchannel reactor, a relatively small volume of material is in the ribbonchannel reactor of the apparatus at any given time, so that a rapid and efficient, high throughput can be achieved. Thus the process and apparatus provide a solution to the problems resulting from the low thermal conductivity of polymeric and other feed composition materials i.e. slow, non-uniform and/or inefficient transfer of heat from heat source to feed composition, and associated with loss or wastage of much energy, and considerably less than optimal conversion of materials and/or non-energy efficient conversion; with the ribbonchannel reactor, which provides a high ratio of heated surface to quantity of heated feed composition. The rapid transfer of heat from the surface of the heated hollow cylinders to the feed composition to achieve a uniform heating of the feed composition, also minimizes the formation of char on the one hand and small, non-condensable hydrocarbons on the other hand. The process and apparatus thus exhibit high through-put and low heat loss. The apparatus can be operated on a continuous basis at a relatively low equipment cost and with a low heat loss. The throughput can be increased to a rate sufficient to provide the economic viability needed in such a recycling process. The process further allows for recovery of non-condensable but combustible gases containing a sufficient quantity of heat-producing capability to heat or provide all needed energy for operation of the process. The process and apparatus are highly efficient in the conversion of plastics to fuel. The polymeric material ( greater than or equal to 70 wt.%) is recovered as hydrocarbon material. The hydrocarbon material obtained is a high viscosity hydrocarbon, is a crude mixture, and has at least some characteristics of crude petroleum such as a complex mixture of components and/or having a noticeable odor. The hydrocarbon material obtained from the process includes 35% diesel-grade hydrocarbon and the remainder of a bunker-C grade hydrocarbon; and is useful as a motor oil base stock. The hydrocarbon materials recovered comprise fuel grade hydrocarbons i.e. the content of impurities, such as sulfur and/or non-hydrocarbon materials, meets industry standards for fuel-grade hydrocarbon materials.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) an apparatus for producing hydrocarbon materials from a feed composition, comprising: a feed port (110); a viscous shear apparatus (112); a thermal decomposition assembly (100) comprising the ribbonchannel reactor comprising the inner heated hollow cylinder, and the outer heated hollow cylinder, such that the inner heated cylinder is substantially concentric and rotatable with respect to the outer heated hollow cylinder, and both the heated hollow cylinders provide heat for increasing temperature of the feed composition to convert the feed composition into a vapor fraction and a solid residue fraction; a low height flighting (146) mounted with respect to the inner heated hollow cylinder and the outer heated hollow cylinder adapted to move the feed composition towards a distal portion of the thermal decomposition assembly; at least one vapor port (134) for removing the vapor fraction; and at least one solids port (142) at the distal portion of the thermal decomposition assembly for removing the solid fraction; and    (2) a ribbonchannel reactor comprising: the inner heated hollow cylinder; the outer heated hollow cylinder; the a low height flighting; the at least one vapor port; and the at least one solids port.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic depiction of the thermal decomposition assembly and portions of a process for converting a feed composition comprising material decomposable into hydrocarbon material, in the ribbonchannel reactor.    Thermal decomposition assembly (100)    Feed port (110)    Viscous shear apparatus (112)    Ribbonchannel reactor (122)    First/inner heated cylinder (124)    Second/outer heated cylinder (126)    Vapor port (134)    Manifold (136)    Condenser (140)    Solids port (142)    Low height flighting. (146)