Abstract: The invention relates to a method for the thermochemical conversion of a fuel, comprising the following steps: a) provision of a fluidised-bed reactor with a central first combustion zone (1) and a second combustion zone (7) that is separated from the first by flow conduction means (2, 15), the first combustion zone (1) being provided with a supply opening (16) for supplying fuel and a unit (3), which lies opposite the supply opening (16) on the floor (B) of the fluidised bed reactor, for deviating a stream of fuel into the second combustion zone (7); b) feeding of fuel through the supply opening (16), so that a stream of fuel forms that is directed towards the floor (B); c) deviation of the stream of fuel on the floor (B) into the second combustion zone (7), so that the stream of fuel is guided in an essentially opposite direction; and d) additional deviation of the stream of fuel in the vicinity of the supply opening (16), causing the stream of fuel to be returned to the first combustion zone.

Abstract: A burner with a housing enclosing a combustion chamber and with an inlet for a gas/air fuel mixture and an outlet for combustion gas is disclosed. The combustion chamber is filled with a porous material whose porosity varies along the combustion chamber in such a way that the pore size increases in the direction of flow of the gas/air mixture so that a critical Peclet number for the pore size and accordingly for flame development results at a boundary surface or in a determined zone of the porous material, above which number a flame can develop and below which number the flame development is suppressed.