A method for controlling a thermal combustion system

A method for controlling a thermal combustion system, comprising:

• a) measuring the flow of a waste stream comprising a compound with calorific value, wherein said waste stream comes from a process underlying a known reaction,
• b) when a change of flow is measured in a), predicting if the flow leads to a temperature change in a combustion of the waste stream of a), wherein said predicting is performed by a diagram or an equation, which allows a temperature of the combustion system to be determined,
• c) when a temperature change is predicted in b),
• c1) calculating a ratio of air, air enriched with oxygen, or oxygen to compounds with calorific value in the waste stream of a), which is required to keep the temperature in the thermal combustion system constant, and
• c2) adjusting the ratio calculated in c1) by increasing or decreasing an amount of fuel to be fed into the combustion system, and/or decreasing or increasing an amount of air, air enriched with oxygen, or oxygen to be fed into the combustion system, and
• d) when the waste stream of a) also comprises bound nitrogen,
• d1) determining if an amount of nitrogen oxides to be formed in the combustion system can be kept at a minimum, when combustion is performed with the ratio of c2), and
• d2) when a requirement of d1) is not met, adjusting the ratio of air, air enriched with oxygen, or oxygen to compounds with calorific value in the combustion system to a sub-stoichiometric value, which allows the amount of nitrogen oxides to be formed in the combustion system to be kept at a minimum, wherein said sub-stoichiometric value is adjusted by an extremum-seeking controller.