NOVELTY - Thermochemical conversion of wet/damp charge, and biological material e.g. coal, biomass or organic wastes into synthesis gas, in a chain of treatment by gasification, comprises pretreatment of filler, prior to the gasification step, where the filler is introduced into a drying enclosure, and in that the drying enclosure is fed by drying hot gas, the gas is constituted of a portion of gas produced in the treatment chain collected after gasification step and recycled using means for pressure releasing towards the drying enclosure.    USE - The treatment chain is useful to produce a synthesis gas for manufacturing liquid fuel, synthetic natural gas, synthetic ammonia, synthetic alcohol or synthetic hydrogen (claimed).    ADVANTAGE - The process is simple, cost effective and eco-friendly.    DETAILED DESCRIPTION - Thermochemical conversion of a wet or damp charge (1), and of a biological material including coal, biomass or organic wastes into a synthesis gas having a determined hydrogen (H2)/carbon monoxide (CO) ratio, in a chain of treatment by gasification which comprises at least one step of the gasification of the charge and a step for converting CO to the steam, where the step of converting CO to the steam is produced in a reactor comprising means for supplying water, comprises pretreatment of the filler, in the treatment chain, prior to the gasification step, where the filler is introduced into a drying enclosure, and in that the drying enclosure is fed by drying hot gas, the gas is constituted of a portion of gas produced in the treatment chain collected after gasification step and recycled using means for pressure releasing towards the drying enclosure. An INDEPENDENT CLAIM is included for a gasification treatment chain for the thermochemical conversion of the wet or damp charge, and of the biological material, comprising a gasification device of the charge and downstream of the gasification device, and a reactor for conversion of the CO to the steam comprising means for feeding water, in a synthesis gas having a determined H2/CO ratio, comprising a drying enclosure of the pretreatment of the wet charge prior to its introduction in the gasification device, in line and upstream of the gasification device, where the drying enclosure is equipped with a hot gas feeder for drying comprising means of extraction located downstream of the gasification step to extract a part of the gas produced in the treatment chain and means of pressure release for recycling the part of the extracted gas towards the drying enclosure.