The invention relates to a method for removing
nitrogen oxides from low-temperature
flue gas, which comprises the following steps of: S1, preparing at least two reactors containing a catalyst and urealoaded on the catalyst, and dividing the reactors into a reaction group and a to-be-reacted group.S2, introducing low-temperature
flue gas into the reaction group for denitration reaction; introducing the low-temperature
flue gas into the reaction group for denitration reactionwhen
urea in the reaction group is consumed to a preset value, and supplementing the
urea in the reaction group.S3, introducing the low-temperature
flue gas into the to-be-reacted group for denitration reactionwhen
urea in the to-be-reacted group is consumed to a preset value, and supplementing the urea in the to-be-reacted group; and S4, alternately introducing the low-temperature
flue gas into the reaction group and the to-be-reacted group according to the mode so as to achieve the continuous denitration of the low-temperature
flue gas.The invention also provides a
system for removing
nitrogen oxides from low-temperature flue gas according to the method.The removal of
nitrogen oxides in low-temperature flue gas is achieved, the problem of
ammonia escape is avoided, and meanwhile, the continuous denitration of low-temperature flue gas and the repeated use of the catalyst are ensured.