Patent ID: 8682499

Claim:
A method for controlling combustion air, comprising: determining an amount of leaking air in a boiler (A L ) by measuring an oxygen flue gas concentration (O 2 ) of the boiler, a boiler power output (P), and an amount of controlled air in the boiler (A C ) and solving equation O 2 =21·{1−a·(P)/(A C +A L )} for the amount of leaking air in a boiler (A L ) using the measured flue gas oxygen concentration of the boiler (O 2 ), the measured boiler power output (P), the measured amount of controlled air in the boiler (A C ), and an air/energy constant (a) for the fuel used in the boiler; determining a constant (k), wherein the constant depends on a heating value of a fuel in the boiler; and adjusting an amount of controlled air supplied to the boiler based on the determined amount of leaking air in the boiler and the determined constant.