METHOD FOR CLEANING AND PASSIVATING WORKING MEDIUM PATH OF STEAM BOILER AND STEAM LINES OF POWER UNIT Russian patent published in 2004 - IPC

FIELD: thermal engineering.

SUBSTANCE: proposed method intended for cleaning and passivating internal heating surfaces of boiler tubes and unheated steam lines of power unit involves use of gaseous oxidant (oxygen) introduced in working medium in the course of boiler starting with turbine being turned off and ferric oxide escape from path monitored. In the process working medium is continuously changed to steam-water mixture condition since very beginning of boiler starting by reducing medium pressure and temperature. Heat transfer within boiler furnace is gradually augmented from stage to stage after ferric oxide escape has ceased at particular cleaning step. Oxidant is fed starting from pressure level of 1.0 - 1.2 MPa in reheat section of boiler, and after pressure in this section rises to 2.0 - 3.0 MPa and ferric oxide escape ceases at this step, pressure and temperature of boiler working medium are raised to values corresponding to those of working medium brought out from steam-water mixture condition in reheat section of boiler, and this condition is maintained up to completion of passivation process.

EFFECT: enhanced cleaning effectiveness of inner surfaces of tubes.

1 cl, 1 dwg