Method and device for automatically adapting a flame to variable operating conditions

A process for combusting a fuel with main and auxiliary flows of oxidant in a combustion zone using a burner upstream of the combustion zone, the burner comprising:

• a block with an exit face facing the combustion zone and an entrance face opposite the exit face, said block comprising at least one first perforation that extends from the entrance face to the exit face which ends at a first level in the exit face, and at least one second perforation that extends from the entrance face to the exit face which ends in the exit face at a second level that is spaced apart from the first level and located below or above the first level;
• at least one fuel injector positioned in the at least one first perforation;
• and at least one main oxidant injector positioned at least one of which is in the at least one second perforation, said process comprising the steps of:
• injecting at least one stream of the fuel into the combustion zone through the at least one fuel injector and the at least one first perforation;
• introducing at least one main stream of the main flow of oxidant into the combustion zone below or above the at least one stream of the fuel and through the at least one main oxidant injector and the at least one second perforation;
• introducing the auxiliary flow of oxidant into the combustion zone and into contact with the at least one fuel stream thereby generating an initial flame in which the at least one main stream of the fuel is partially combusted with the auxiliary flow in the combustion zone and in which non-consumed fuel that was not combusted in the initial flame with the auxiliary flow is yielded;
• downstream of the initial flame, mixing the at least one main stream of the main flow of oxidant with the non-consumed fuel thereby completing combustion of the at least one main stream of the fuel downstream of the initial flame;
• measuring an emission intensity of the initial flame;
• adjusting a flow rate of the main flow of the oxidant, depending on the measured emission intensity so that the emission intensity of the initial flame is located in a preset zone or range of emission intensity;
• measuring an oscillation frequency of the initial flame;
• and
• adjusting a ratio between the flow rate of the main flow of the oxidant and a flow rate of the auxiliary flow of the oxidant, depending on the measured oscillation frequency.