METHOD OF MAINTENANCE CLEANING AND PASSIVATION OF DRUM BOILER PIPE INNER SURFACE AND METHOD OF MAINTENANCE CLEANING AND PASSIVATION OF PIPE INNER SURFACE OF COMBINED-CYCLE PLANT WASTE-HEAT BOILER (VERSIONS) Russian patent published in 2014 - IPC F28G9/00 

FIELD: power engineering.

SUBSTANCE: proposed method comprises processing of pipes in isolated circuit by hot detergent water-based solution containing nitrogen-bearing chemical reagent. Said nitrogen-bearing chemical reagent represents a film-forming amine while batching of detergent solution is performed at concentration of chemical reagent in the boiler of (250÷300) mcg/dm³. Cleaning is performed in one step at boiler pressure of 1.5÷2.5 MPa and working fluid temperature not exceeding 230°C to stabilisation of iron content in boiler water. Passivation is performed at boiler pressure of 2.5÷15.5 MPa and working fluid temperature equal to saturation temperature for boiler pressure to stabilisation of iron content in boiler water not exceeding 50 mcg/dm³.

EFFECT: lower costs.

2 cl, 2 tbl