Patent ID: 9429319
Filing Date: 2016-08-30
CPC Classification: F23C,F23J,F23L,Y02E

Claim Text:
1. A boiler combustion system comprising: a boiler equipped with a burner configured to burn fuel with combustion gas and a two-staged combustion gas input port configured to supply combustion gas to a neighborhood of a combustion area of the burner; a flue gas treatment system configured to treat flue gas discharged from the boiler; a flue gas supply device configured to supply the flue gas extracted from the flue gas treatment system to the boiler; supply lines configured to supply the flue gas supplied from the flue gas supply device, including a combustion gas supply line configured to supply the flue gas as the combustion gas to the burner, a fuel carrier gas supply line configured to supply the flue gas as fuel carrier gas used to transport the fuel to the burner, and a two-staged combustion gas supply line configured to supply the flue gas as two-staged combustion gas to the two-staged combustion gas input port; an oxygen supply device configured to produce oxygen-rich gas and supply the oxygen-rich gas to the combustion gas supply line and the fuel carrier gas supply line via respective flow regulators; a combustion air supply device configured to supply combustion air to each of the combustion gas supply line, the fuel carrier gas supply line, and the two-staged combustion gas supply line; a first damper configured to regulate a flow rate of gas supplied from the combustion gas supply line to the burner; a second damper configured to regulate a flow rate of gas supplied from the two-staged combustion gas supply line to the two-staged combustion gas input port; and a control unit configured to control openings of the first damper and the second damper, switching operation between the flue gas supply device and the combustion air supply device, and start of operation of the oxygen supply device, wherein when switching from oxygen combustion mode to air combustion mode the control unit performs control so as to switch from operation of the flue gas supply device to operation of the combustion air supply device and change the second damper from closed to open with the first damper kept open, and when switching from air combustion mode to oxygen combustion mode, the control unit performs control so as to switch from operation of the combustion air supply device to operation of the flue gas supply device, start operating the oxygen supply device, and change the second damper from open to closed with the first damper kept open.