NOVELTY - The modular plant comprises first and second basic modules including a reactor (9) rotating about a central longitudinal axis having an inclination of 0-45 degrees in respect to a horizontal plan, a stationary casing, an assembly, and a chamber. The reactor comprises: a cylindrical center body closed at a first entrance end by a stationary head (8) and at a second end by a head fixed to the reactor; a first conduit for introducing a carbonaceous matrix into the reactor for converting the matrix; and a second conduit for introducing a thermally conductive carrier (4) into the reactor.    USE - The modular plant is useful for performing conversion processes of carbonaceous matrix including solids such as solid matrices for mixing in cocktails and char, liquids such as vegetable oils, oils from algal biomass, natural and/or synthetic esters, synthetic liquids, hydrocarbon fractions and gases such as biogas, pyrolysis gas and syngas into fuel or other useful products such as energetic or bio-energetic carriers or energy or bio-energy.    ADVANTAGE - The modular plant is capable of easily and safely performing the conversion processes of the carbonaceous matrix without adverse environmental impact.    DETAILED DESCRIPTION - The modular plant comprises first and second basic modules including a reactor (9) rotating about a central longitudinal axis having an inclination of 0-45 degrees in respect to a horizontal plan, a stationary casing, an assembly, and a chamber. The reactor comprises: a cylindrical center body closed at a first entrance end by a stationary head (8) and at a second end by a head fixed to the reactor; a first conduit for introducing a carbonaceous matrix into the reactor for converting the matrix; and a second conduit for introducing a thermally conductive carrier (4) into the reactor that is fixed to the stationary head. The stationary casing: integrally encloses the reactor so that it is sealed in respect to the external environment; and comprises openings for the passage of the first and second conduits and for the exit of the converted carbonaceous matrix and the thermally conductive carrier, and a thermally and/or acoustically insulating layer that is internal and/or external, where an auxiliary heating system is integrated. The assembly rotatably drives the reactor that is deprived of internal members having a relative rotation motion in respect of the cylindrical body. The thermally conductive carrier is constituted by solid bodies such as metal spheres or a liquid consisting of molten metals, alloys and salts, liquefied cryogenic fluids and substances such as oils, water solutions and organic fluids that are liquid at room temperature. The modular plant further comprises a device for cooling or heating the conductive carrier that is continuously and in closed loop re-circulated within the reactor, and a controlled feeding module. One internal member suitable for interacting with the matrix and the conductive carrier is fixed to the internal surface of the reactor. The internal member is: of a drawer, ploughshare, winglet, solid or perforated Archimedean screw with solid or perforated shaft, solid or perforated spiral or basket type; provided with injectors; and associated to a rotating distributor of a process fluid, which is leak-proof assembled on the stationary head and is suitable for allowing the feeding of the process fluid into the reactor. The driving assembly comprises: an entity comprising motorized rollers, which interact with the external surface of the body of the reactor by friction; a motorized pinion engaging a toothed crown fixed to the reactor; a motorized shaft fixed outwards the mobile head in correspondence of the longitudinal axis; and a flexible member such as a belt or a chain, which connects a motor shaft to an external surface of the body of the reactor. The second head of the center body of the reactor has a grid surface, whose mesh has a size allowing the passage of the converted matrix towards the respective opening done in the casing and retaining the solid bodies making thermally conductive carrier.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a basic module of a modular plant.    Fixed stationary body (1)    Thermally conductive carriers (4)    Inlet (5)    Stationary fixed head (8)    Reactor. (9)