Arrangement and burner automation for adjusting the ratio between supplied amounts of fuel and air in an industrial burner

A method for reducing nitrogen oxide(s) and carbon monoxide from flue gases of an industrial burner said method comprising:

• providing a burner configured to burn a fuel, the burner comprises:
• a mixing zone for mixing the fuel with a combustion air, followed by a combustion chamber, followed by a flue gas conduit comprising a multi-zone three-way catalytic converter comprising two or more successive catalytic zones, measurement instruments comprising one or more oxygen (O2) sensors, a plurality of carbon monoxide (CO) sensors and one or more nitrogen oxides (NOx) sensors, and a burner automation system comprising a central processing unit responsive to input signals from the measurement instruments and providing control signals to devices/actuators controlling delivery of the fuel and of the combustion air;
• delivering through corresponding supply conduits inlet flows of the combustion air and of the fuel to the burner and further into the mixing zone using the burner automation system;
• generating flue gases in the combustion chamber by combusting the combustion air and the fuel delivered into the mixing zone;
• directing the flue gases to said multi-zone three-way catalytic converter;
• providing concentration in the flue gases after the multi-zone three-way catalytic converter for the NOx and the CO to be within corresponding predefined ranges by measuring of concentration of the NOx and the CO being performed using corresponding sensors of the plurality of CO sensors and of the one or more of NOx sensors, said providing is implemented using adjustment of an inlet flow of a combustion air and an inlet flow of the fuel arriving into the mixing zone using said burner automation system, so that:
• a mean amount of residual oxygen in moles compared to a mean amount of carbon monoxide in moles, is stochiometric about 0.5/1 (mole/mole) in flue gases prior to a first catalytic zone or at the first catalytic zone of the multi-zone three-way catalytic converter, and
• an amount of the residual oxygen is within a predetermined percentage range in the flue gases prior to the first catalytic zone or at the first catalytic zone of the multi-zone three-way catalytic converter,
• where measuring amounts of the residual oxygen and CO being performed using corresponding sensors of the plurality of CO sensors and the one or more 02 sensors;
• and
• adjusting the inlet flows of the combustion air and the fuel arriving into the mixing zone using said burner automation system, the adjusting is provided in two stages comprising:
• a primary adjustment providing a first predetermined percentage range of oxygen in flue gases prior to the first catalytic zone or at the first catalytic zone of the multi-zone three-way catalytic converter, based on estimating/calculating and a corresponding control signal at least to one of actuating valves, provided by the central processing unit, to facilitate adjusting a primary inlet flow of at least one of the fuel and the combustion air through a corresponding fuel or combustion air first transfer pipe line, and
• a secondary adjustment providing a second predetermined percentage range of oxygen, the second predetermined percentage range is below the first predetermined percentage range, in the flue gases prior to the first catalytic zone or at the first catalytic zone of the multi-zone three-way catalytic converter based on a further corresponding control signal, provided by the central processing unit using the measured amount of the residual oxygen, at least to one of further actuating valves to provide adjusting of a secondary inlet flow of the at least one of the fuel and of the combustion air through a corresponding fuel or combustion air second transfer pipe line.