The invention provides a steam oxygenating step-down pressure blowing
system and method for a boiler. The steam oxygenating step-down pressure blowing
system comprises a super-heater unit and a reheater unit, wherein an oxygenating pipeline I is connected to an inlet header pipeline of a roof
superheater of the super-heater unit; an oxygenating pipeline II is connected to an outlet header connecting
pipe of a vertical low temperature
superheater; an oxygenating pipeline III is connected with an outlet header connecting
pipe of a platen
superheater; the oxygenating pipeline I, the oxygenating pipeline II and the oxygenating pipeline III are connected with first
oxygen storage devices through a first oxygenating mother
pipe; an inlet header
nitrogen filling interface of a low temperature reheater of the reheater unit is connected with an oxygenating pipeline IV; an inlet header of a high temperature reheater is connected with an oxygenating pipeline V; and the oxygenating pipeline IV andthe oxygenating pipeline V are connected with second
oxygen storage devices through a second oxygenating mother pipe. According to the steam oxygenating step-down pressure blowing
system and the method, by reasonably selecting connecting points of a temporary oxygenating system pipeline and boiler heated surfaces, dense protective films are formed on all the heated surfaces of the boiler and
metal surface of the inner wall of a steam pipeline; blowing times are few, and the consumed time is short; and a
chemical cleaning procedure of the boiler is omitted, so that the cost is reduced.