Controlling a combustion device to lower combustion-induced pulsations by changing and resetting fuel stagings at different rates of change
View Patent ↗A method is provided for operating a combustion device having at least one premix burner equipped with fuel stagings and is connected to a combustion chamber. The method includes changing, during transient operating states, the fuel staging of the at least one premix burner in accordance with combustion-induced pulsations which occur in the combustion chamber. A pulsation level of the pulsations which occur in the combustion chamber is continuously determined, the fuel staging of the at least one premix burner is changed for lowering the pulsation level if the pulsation level exceeds a predetermined maximum value, and, after a predetermined time interval, by the fuel staging being reset to the undisturbed value which determines the respective operating point if within the predetermined time interval the predetermined maximum value is not exceeded.
1. A combustion device comprising a combustion chamber and at least one premix burner connected to the combustion chamber and equipped with fuel stagings, wherein the fuel stagings are changeable by a control unit with an associated timer, the control unit being communicatively connected to at least one sensor that is configured to detect a pulsation level of combustion induced pulsations, wherein the control unit is configured to lower the pulsation level when the pulsation level exceeds a predetermined maximum value within a first predetermined time interval by:
(i) changing the fuel stagings of the at least one premix burner with a first rate of change to lower the pulsation level when the pulsation level exceeds the predetermined maximum value within the first predetermined time interval to initiate adjustment of an operational point of the combustion device from a first operational point to a second operational point, and
(ii) resetting the fuel stagings with a second non-zero rate of change to a value that determines the second operational point of the combustion device when the predetermined maximum value is not exceeded within a second predetermined time interval that is greater than zero seconds and is subsequent to the first predetermined time interval, the second non-zero rate of change being smaller than the first rate of change.
2. The combustion device of claim 1 , wherein the control unit is further configured so that an overall fuel flow is kept constant while the fuel stagings of the at least one premix burner are being changed with the first rate of change to lower the pulsation level of combustion.
3. The combustion device of claim 1 , wherein the combustion device is a gas turbine.
4. The combustion device of claim 1 , wherein the at least one premix burner is comprised of a plurality of burners that are each fed fuel from at least two distribution lines.