Abstract: A method to regulate overfire air passing through an overfire air duct and entering a flue gas stream in a combustion system including: directing overfire air into an inlet of the overfire air duct, passing the overfire air through the duct and discharging the overfire air into the flue gas stream in the combustion system; adjusting a flow rate of overfire air entering the inlet using a damper adjacent the inlet, and moving the damper parallel along an axis of the overfire air duct to increase and decrease the overfire air entering the inlet, wherein the damper has an open position at which the damper is extended out of the inlet and a closed position in which the damper is substantially in the inlet and blocking air entering the inlet.

Abstract: A method to regulate overfire air passing through an overfire air duct and entering a flue gas stream in a combustion system including: directing overfire air into an inlet of the overfire air duct, passing the overfire air through the duct and discharging the overfire air into the flue gas stream in the combustion system; adjusting a flow rate of overfire air entering the inlet using a damper adjacent the inlet, and moving the damper parallel along an axis of the overfire air duct to increase and decrease the overfire air entering the inlet, wherein the damper has an open position at which the damper is extended out of the inlet and a closed position in which the damper is substantially in the inlet and blocking air entering the inlet.

Abstract: Embodiments of the invention can include systems and methods for facilitating varying coal pipes for a pulverized coal burner. In one embodiment, a method for improving operation of a pulverized coal burner comprising at least one burner comprising at least one coal pipe having an inner diameter, and an outer diameter. The method can include installing at least one sleeve or at least one liner within the coal pipe between the inner and outer diameter of the coal pipe, wherein velocity of a primary air and pulverized coal mixture is increased in an upstream portion of the coal pipe. The method can also include reducing the at least one sleeve or liner, wherein velocity of the primary air and pulverized coal mixture is reduced in a downstream portion of the coal pipe.

Abstract: A damper and overfire air duct in a combustion system having a combustion structure defining a flue gas passage, the damper and overfire air duct including: an inlet to the overfire air duct and an outlet to the duct discharging overfire air into the flue gas passage, and the damper aligned with an axis of the overfire air duct, and having an open position axially distal to the inlet and a closed position at least partially in the inlet and duct, wherein the damper is movable axially between the open and closed positions.

Abstract: A damper and overfire air duct in a combustion system having a combustion structure defining a flue gas passage, the damper and overfire air duct including: an inlet to the overfire air duct and an outlet to the duct discharging overfire air into the flue gas passage, and the damper aligned with an axis of the overfire air duct, and having an open position axially distal to the inlet and a closed position at least partially in the inlet and duct, wherein the damper is movable axially between the open and closed positions.