NOVELTY - The solid load undergoes pyrolysis and gasification as a fluidized bed in Z1. It is then separated in Z2 into a gas, and a solid which is fed to Z3 where it is gasified into a dense fluidized bed. The effluents from Z3 are separated in Z4 into a gas and a solid. The solid phase is burned in Z5, which also contains means of transferring the heat-carrying solid from the combustion in Z1    USE - Obtaining energy from a solid load containing organic material, in particular organic waste    ADVANTAGE - Increased capacity, better conversion of the waste, to produce a synthesis gas with a higher calorific value.    DETAILED DESCRIPTION - Z5 contains means of burning the solid phase from Z4. Z1 includes means of introducing an oxidizing gas and means of transferring the heat-carrying solid from the combustion. There are means of transferring the gas from Z2 to Z4. Z5 includes a first area for burning the solid in a fluidized bed, a separation zone Z6 and a zone Z7 where the solid from Z5 is burned in a fluidized bed and the heat-carrying solid is transferred from Z1. Z3 includes means of supplying a reactive vector gas and the load. Z5 can be fed with a complementary fuel. The process is carried out in conditions which allow the heat-carrying solid to be regenerated continuously at a temperature of between 700 and 1100 deg. C. The heat-carrying solid is dolomite, mica, olivine, trona, borax, bentonite or a derivative thereof, an inert support impregnated with metal salts or alkali alkali-earth salts, alumina silicates giving an acid property. The load has a grain size of 0.1 to 100mm. The reactive vector gas is steam, carbon dioxide or a mixture of the two and may include hydrogen and/or methane and/or carbon monoxide. The fluidized bed operations are at between 600 and 1000 deg. C and combustion is at between 800 and 1200 deg. C. The initial mass ratio between the reactive vector gas and the load is between 0.1 and 5. The mean time that the solid particles are in the fluidized bed is between 0.5 and 20 seconds and in the dense fluidized bed is between 30 seconds and an hour. The solid load is a biomass, domestic and/or industrial waste, waste from a purification or industrial plant, agricultural residues and by-products, or ground polluted by hydrocarbons.    DESCRIPTION OF DRAWING(S) - The figure shows the invention in schematic form    Pyrolysis and gasification into a fluidized bed (Z1)    Separation into a gas and a solid (Z2)    Gasification of solid into a dense fluidized bed (Z3)    Separation into a gas and a solid (Z4)    Combustion (Z5)