METHOD FOR CLEANING INTERNAL SURFACE OF BOILER Russian patent published in 2017 - IPC F28G9/00 

FIELD: chemistry.

SUBSTANCE: invention can be used in the operational cleaning of the internal surfaces of small and medium-pressure water boilers and steam boilers not exceeding 15 atm from the deposits, including high-temperature silicates, calcium, and magnesium phosphates, and insoluble or hardly soluble in mineral acids. Water prepared is used as a cleaning solution after Na-cationization with a total alkalinity of 4-6 mg_*ekv/dm³, and a total hardness of 0.002 mg_*EQ/dm³ at a temperature of 60-90°C with pH of 7.0 and 8.5, with the addition of a complexing agent - "Trilon B" - disodium salt of ethylenediaminetetraacetic acid and phosphate, the concentration of which in the boiler water is raised to 50-168 mg/dm³ of disodium salt of ethylenediaminetetraacetic acid, and 10-20 mg/dm³ of PO₄³, respectively. The dosage of "Trilon B" and phosphate is carried out by two independent pumps into the suction header of the boiler feed pump. Boiler purge is carried out according to the constant analytical control, maintains the level of hardness and salt content of the boiler water in accordance with the technical requirements of the boiler.

EFFECT: improving the environmental characteristics of the cleaning process by eliminating the formation of aggressive wastewater, cleaning during the operation of the equipment.

3 cl, 1 tbl