This utility model discloses a
system for combined
denitrification under full-load conditions in a
circulating fluidized bed boiler, comprising a wide-temperature-range SNCR
denitrification module and a
flue gas circulation module. The injectors in the wide-temperature-range SNCR
denitrification module are arranged in the inlet
flue of the high-temperature separator, the inlet
flue of the high-temperature
superheater, or the
boiler furnace. The
flue gas circulation module includes a
flue gas circulation header and
flue gas circulation
branch pipes arranged along the flue gas flow direction. The flue gas circulation header connects to the flue gas circulation
branch pipes, which are connected to the
air preheater via a primary air fan. The inlet of the flue gas circulation header connects to the outlet of the induced draft fan. This utility model extends the
lower limit of the conventional 800~1050℃ temperature window to 650℃. It uses
ethanol as a low-temperature additive, resulting in relatively low denitrification costs and convenient
ethanol addition and removal. Compared with existing SCR denitrification technology, the
system is simpler and more economical. It does not require boiler modification, nor does it require additional denitrification reactors and catalysts, making the
system relatively simple and facilitating switching between low-temperature denitrification mode and conventional denitrification mode.