NOVELTY - The gasogen comprises a gas exhaust gate (5), which blocks a pipe connected to a combustion chamber (10), an exhaust pipe (6) for pyrolysis gases towards an ancillary gas exhaust funnel (11), an extraction grid for ashes proper to the fuel, which are extracted from an exocentric bottom of the gasogen, and peripheral blower and a central blower to extract the ashes with two sets of steam and/or inert gases injection nozzles. The fixed upstream type gasogen comprises refrigerated walls, where a material or biomass to be gasified is subjected to series of processes such as drying.    USE - The gasogen is useful for producing gases for external combustion in boilers, furnaces, internal combustion engines and other devices or apparatuses which use the gases and improving the treatment of biomass (all claimed), where the gases include combustible gas such as a fuel, a natural gas or a fuel liquid gas.    ADVANTAGE - The gasogen can be operated with high safety and reliability and without stops for maintenance and/or cleaning, allows easy and efficient extraction of the ashes, and is economical to maintain.    DETAILED DESCRIPTION - The gasogen comprises a gas exhaust gate (5), which blocks a pipe connected to a combustion chamber (10), an exhaust pipe (6) for pyrolysis gases towards an ancillary gas exhaust funnel (11), an extraction grid for ashes proper to the fuel, which are extracted from an exocentric bottom of the gasogen, and peripheral blower and a central blower to extract the ashes with two sets of steam and/or inert gases injection nozzles. The fixed upstream type gasogen comprises refrigerated walls, where a material or biomass to be gasified is subjected to series of processes such as drying, pyrolysis or carbonization, reduction of the carbon dioxide generated into carbon monoxide and burning of the residual carbon, and gasified gases goes through a feeding system. The gasogen walls are formed by a number of cooling pipes with heat dissipation membranes, where the membranes are metal plates fixed to cooling pipes. The grid is an exocentric rotating grid for extracting the ashes. The grid consists of internal plates, external plate and an upper plate, which rotates on a shift not coincident with the gasogen vertical shift, and is defined by a succession of overlapped plates with a decreasing diameter. Channels are present between the overlapped plates for the passage of a gasification air and allowing fall of the ashes towards a hopper located at the bottom of the gasogen. The channels define respective spaces of 5-150 mm high. The grid includes a system of plates whose thickness is 6-50 mm. The plates are strengthened by metallic gusset plates covered with hard metal to minimize wear and produce an abrasive effect and breakage of compacted ashes. The central blower is located between the upper plate and the plate immediately below it. The set of nozzles is located in the peripheral blower between the external plate and the fixed area of a bottom lateral lock in the gasogen to ease the movement and extraction of the ashes. An ancillary funnel is provided for the deviation of gases towards the exterior, and a gas exhaust valve is provided for the pyrolysis gases generated in the gasogen. The ancillary funnel includes a torch (12) to burn the gases generated. An INDEPENDENT CLAIM is included for a process to improve the treatment of the biomass using the gasogen.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a gasogen.    Gas exhaust gate (5)    Exhaust pipe (6)    Combustion chamber (10)    Ancillary gas exhaust funnel (11)    Torch. (12)