SCR (selective catalytic reduction) denitration system, heating device and denitration method

The invention relates to an SCR (selective catalytic reduction) denitration system, a heating device and a denitration method. The SCR denitration system comprises an auxiliary boiler and SCR denitration equipment, a smoke inlet pipeline and a smoke evacuation pipeline of the auxiliary boiler are respectively communicated with a smoke flue of a power generating boiler, the end, connected with the smoke flue, of the smoke inlet pipeline is the first communication end, the end, connected with the smoke flue, of the smoke evacuation pipeline is the second communication end, the first communication end and the second communication end are respectively positioned in an upstream and a downstream of the SCR denitration equipment, the smoke evacuation pipeline is provided with an isolation mechanism used for controlling on-off of the smoke evacuation pipeline, the smoke inlet pipeline is provided with a blower, and smoke in the smoke flue can be blown into the auxiliary boiler. Compatibility and cooperation of the SC