A reactor air supply system including a first air inlet configured to receive air supplied from a first air supply. The system includes a burner having a burner nozzle configured to discharge fuel for mixing with the first air and configured to ignite the fuel/air mixture. A second air inlet is provided that is configured to receive heated air supplied from a second air supply, and a duct is provided to receive the ignited fuel/air mixture and the heated air supplied from the second air supply. The duct has an outlet configured to connect to a reactor. The duct is configured to receive the heated second air such that the heated second air mixes with the ignited fuel/air mixture at a location downstream of the burner.