Method for controlling a combustion device
AssigneeSiemens Energy Global GmbH & Co. KG
InventorsEberhard Deuker, Benedict Kriegler
Life of this patent
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Abstract
A method for controlling a combustion process in a gas turbine wherein a combustion chamber, a control device storing a calculation model of the combustion process, and an exhaust air measurement device are used. A permissible limit value for nitrogen oxides and for carbon monoxide as pollutants is set. The actual value of at least one of the two pollutants is measured continuously in the exhaust air. When a signal to reduce the power of the gas turbine to a lowest possible value is given, then a minimum fuel supply at which the limit values are complied with is calculated. The fuel supply is then reduced either until the calculated minimum fuel supply is reached or until the continuously measured proportion of the pollutant reaches the permissible limit value.
Claims19
A method for controlling a combustion process in a combustion device, comprising a combustion chamber, in which fuel is burnt with supply air, and at least one burner, which delivers the fuel and/or the supply air into the combustion chamber, and a control device, in which a calculation model of the combustion process is stored, and an exhaust air measurement device, which detects the actual proportion of nitrogen oxides and the actual proportion of carbon monoxide;
- the method comprising:
- setting a permissible limit value for the proportion of nitrogen oxides and determining a first target value based on the permissible limit value for the proportion of nitrogen oxides minus a tolerance;
- setting a permissible limit value for the proportion of carbon monoxide and determining a second target value based on the permissible limit value for the proportion of carbon monoxide minus a tolerance;
- continuously detecting the actual proportion of nitrogen oxides and the actual proportion of carbon monoxide in the exhaust air;
- acquiring a signal for setting a minimum power;
- calculating a minimum total fuel supply, using the calculation model, at which the expected proportion of carbon monoxide and the expected proportion of nitrogen oxides, respectively, reach the respective first and second target values;
- while continuously monitoring the actual proportion of nitrogen oxides and the actual proportion of carbon monoxide in the exhaust air, reducing the fuel supply as far as the calculated minimum fuel supply or until the respective first and second target values for nitrogen oxides and carbon monoxide is reached, to ensure that the respective first and second target values for nitrogen oxides and carbon monoxide are complied with when the fuel supply is reduced;
- and
- wherein the calculation is carried out repeatedly, wherein the fuel supply is increased when exceeding of one of the permissible limit values is detected, and the fuel supply is further reduced when undershooting of both the first and second target values is detected.
A method for controlling a combustion process in a combustion device, comprising a combustion chamber, in which fuel is burnt with supply air, and at least one burner, which delivers the fuel and/or the supply air into the combustion chamber, and a control device, in which a calculation model of the combustion process is stored, and an exhaust air measurement device, which detects the actual proportion of nitrogen oxides and the actual proportion of carbon monoxide;
- the method comprising:
- setting a permissible limit value for the proportion of nitrogen oxides and determining a first target value based on the permissible limit value for the proportion of nitrogen oxides minus a tolerance;
- setting a permissible limit value for the proportion of carbon monoxide and determining a second target value based on the permissible limit value for the proportion of carbon monoxide minus a tolerance;
- continuously detecting the actual proportion of nitrogen oxides and the actual proportion of carbon monoxide in the exhaust air;
- acquiring a signal for setting a minimum power;
- calculating a minimum total fuel supply, using the calculation model, at which the expected proportion of carbon monoxide and the expected proportion of nitrogen oxides, respectively, reach the respective first and second target values;
- while continuously monitoring the actual proportion of nitrogen oxides and the actual proportion of carbon monoxide in the exhaust air, reducing the fuel supply as far as the calculated minimum fuel supply or until the respective first and second target values for nitrogen oxides and carbon monoxide is reached, to ensure that the respective first and second target values for nitrogen oxides and carbon monoxide are complied with when the fuel supply is reduced;
- wherein the combustion device comprises at least one main burner and at least one secondary burner, which each delivers fuel and/or supply air into the combustion chamber;
- wherein the method further comprises:
- when calculating the minimum fuel supply, determining a distribution of the fuel between the main burner and the secondary burner at which the expected proportion of carbon monoxide and the expected proportion of nitrogen oxides, respectively, reach the respective second and first target values;
- reducing the fuel supply, taking into account the previously calculated distribution of the fuel between the main burner and the secondary burner.
Dependencies are inferred from the claim text.