Patent ID: 8453585

Claim:
A method of transitioning to oxy-combustion comprising: providing a boiler; combusting a fossil fuel in the presence of air to create a flue gas wherein a burner is provided with a primary air stream and a secondary air stream; measuring a flue gas oxygen concentration at the boiler exit; increasing the flue gas oxygen concentration at the boiler exit by introducing an oxygen stream to the burner; opening a flue gas recycle damper; providing an additional oxygen stream to an oxygen mixer; creating a secondary oxygenated recycled flue gas by mixing the flue gas with the additional oxygen stream; transitioning from the secondary air to the secondary oxygenated recycled flue gas by incrementally closing a secondary fresh air intake damper; creating a primary oxygenated recycled flue gas by mixing the flue gas with the additional oxygen stream; and transitioning from the primary air stream to the primary oxygenated recycled flue gas by incrementally closing a primary fresh air intake damper; wherein the primary oxygenated recycled flue gas and the secondary oxygenated recycled flue gas are preheated via an air heater; and wherein the primary oxygenated recycled flue gas and the secondary oxygenated recycled flue gas are created upstream of the air heater.