Gas turbine combustor having a first combustion zone receiving multiple fuels and a second combustion zone receiving a fuel not containing nitrogen atoms

A combustion system comprising:

• a combustor including a first combustion region and a second combustion region continuous with the first combustion region on a downstream side of the first combustion region;
• a first burner including an injection portion of ammonia as first fuel, the injection portion of ammonia facing the first combustion region, and a first injection portion of second fuel not containing nitrogen atoms, the first injection portion facing the first combustion region;
• a second burner including a second injection portion of the second fuel, the second injection portion facing the second combustion region;
• and
• a control device that adjusts a second fuel flow rate ratio that is a ratio between a flow rate of the second fuel injected from the first injection portion and a flow rate of the second fuel injected from the second injection portion,
• wherein in a case where a temperature of the first combustion region is lower than an upper limit temperature, the control device adjusts the second fuel flow rate ratio such that all the second fuel supplied to the combustor is injected from the first injection portion and that the second fuel is not injected from the second injection portion, and
• wherein in a case where the temperature of the first combustion region reaches the upper limit temperature, the control device adjusts the second fuel flow rate ratio such that a part of the second fuel supplied to the combustor is injected from the second injection portion.