METHOD OF CLEANING STEAM BOILERS Russian patent published in 2000 - IPC

FIELD: chemical method of cleaning inner surfaces of tubular space; washing steam boiler used for ammonia production. SUBSTANCE: method consists in alkaline washing of surfaces with aqueous solution containing 5 percent of Na₃PO₄ and 5 percent of Na₂CO₃ at temperature of 90 C for 5 hours, washing- off with demineralized water, flushing with solution containing 5 percent of ammonium chloride and hydrochloric acid with corrosion inhibitors at 50 C for five hours, washing-off with demineralized water and passivation with 1-% solution of NaNO₂ at 50 C for four hours. EFFECT: 100-% cleaning of equipment; reduced cleaning time reduced aggressive properties of washing solution.