Catalyst self-activation hot air circulation system

The utility model discloses a catalyst self-activation hot air circulation system which is arranged at a denitration reactor, and at least one catalyst layer is arranged in the denitration reactor. An air inlet of the denitration reactor is connected with a bag-type dust collector, an air inlet of the bag-type dust collector is connected with a smoke inlet pipeline, an air outlet of the denitration reactor is connected with a smoke outlet pipeline, the device comprises an air inlet control valve arranged between an air outlet of the bag-type dust collector and the air inlet of the denitration reactor, and an air outlet control valve is arranged at the air outlet of the denitration reactor; the denitration reactor is provided with a circulating air outlet and a circulating air return port, and a hot air circulating device is arranged between the circulating air outlet and the circulating air return port; the circulating air outlet is further connected with a smoke return fan through a pipeline, an air outlet o