Device for reducing operation oxygen amount under deep peak regulation working condition of CFB boiler and CFB boiler

The utility model discloses a CFB (circulating fluid bed) boiler and a device for reducing running oxygen quantity under deep peak regulation working condition of the CFB boiler, a secondary air recirculation pipeline is arranged by being connected with a CFB boiler main body, and after the secondary air recirculation pipeline is opened in a low load state, air is introduced into an air preheater through an air feeder; one part of hot secondary air generated after heating enters the CFB boiler body for combustion supporting, the other part of hot secondary air enters an inlet of a primary air fan through a hot air recirculation pipeline and is mixed with primary air to be introduced into an air preheater to be heated to generate hot primary air, the hot secondary air with the high temperature is mixed into the inlet of the primary air fan, and at the moment, the oxygen content of the hot secondary air is low; therefore, the total air volume and the oxygen content during deep peak regulation are reduced, the r