The known technique for washing out a steam generator consists of a consecutive three-phase processing of the working surface of the steam-and-water chamber of the steam generator using water solutions with the stirring of the appropriate solution during each phase.

The new technology is different in that a 10-30 g/l ammonia acetate solution is used during the first phase.

During the second phase a solution of 15-40 g/l ethylenediaminetetracetic acid and hydrazine of no higher than 5g/l is used. In the third phase an ammonia solution of 10-15 g/l ammonia acetate is used.

The new technique has six modifications.

1. The specificity of the first modification is that the wash-out process takes place at the solution temperature ranging from 25 to 40^oC, the initial pH value being no less than 10.5 provided that the pH initial value (i.e. a logarithm of the concentration of hydrogen ions taken with a minus sign: ) is obtained by adding ammonia to the solution.

2. The specificity of the second modification is that the wash-out process takes place at the solution temperature ranging from 60 to 95^oC, the initial pH value being within 5.0-5.5, provided that the pH initial value is obtained by adding ammonia to the solution.

3. The specificity of the third modification is that stirring the solution during the first phase is carried out by way of compressed air bubbling (i.e. stirring with compressed air, G.Ch.).

4. The specificity of the fourth modification is that stirring the solution during the second phase is carried out by way of injecting vapor into the solution and/or by making the solution circulate through the steam generator.

5. The specificity of the fifth modification is that the first phase is completed as soon as the copper concentration in the solution has stabilized.

6. The specificity of the sixth modification is that the second phase is completed as soon as the concentration of iron in the solution has stabilized while a free complexone is present in the solution.

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