Subcritical drum boiler water treatment method

Abstract

The invention relates to a subcritical drum boiler water treatment method which is implemented by adding sodium hydroxide into boiler water until the weight percent of sodium hydroxide in the boiler water is 0.08-1%. The pH value of the boiler water before adding the sodium hydroxide is 9.2-9.25, and the pH value of the boiler water after adding the sodium hydroxide is 9.45-9.5. Compared with the prior art, after the method is used for treating the boiler water, the pH value, hydrogen electric conductivity, chlorine ions and other indexes of the boiler water are effectively monitored, the boiler water pollution discharge-condensation water fine treatment mixed bed can operate in a more economic and reasonable way, the vapor quality of the thermodynamic system is reliably ensured, the salt content of the boiler water is greatly lowered and is easy to control, the chlorine ion content of the boiler water is greatly lowered and does not have the overproof phenomenon as compared with the phosphate treatment working conditions, and the hidden danger of corrosion of chlorine ions to the boiler tube is effectively prevented. When the boiler is shut down for inspection, the thermodynamic system is clean, the water wall tube oxide film is uniform, smooth and compact and does not have the phenomenon of pitting corrosion, and the scaling rate is less than 40 g / m<2>.a, thereby satisfying Grade 1 in Standard DL / T561-95 for evaluation on scaling rate from the water wall to the fire side and corrosion.

Description

technical field [0001] The invention relates to a boiler furnace water treatment method, in particular to a subcritical drum boiler furnace water treatment method. Background technique [0002] At present, for units of various pressure levels in my country, phosphate (PT) and full volatile treatment (AVT) are mainly used for boiler water treatment. During the phosphate treatment of furnace water, the phenomenon of phosphate "temporary disappearance" will occur, resulting in the pH value of the furnace water, PO 4 3- The pipe cutting inspection shows that there are acid phosphate deposits and local pitting on the pipe wall. In addition, during phosphate treatment, it is difficult to accurately measure the salinity level of the furnace water, and the concentration of chloride ions in the furnace water often occurs, and the chloride ion content reaches the milligram level at the highest level, which intensifies the corrosion of the furnace tube to a certain extent. When the ...

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Problems solved by technology

During the phosphate treatment of furnace water, the phenomenon of phosphate "temporary disappearance" will occur, resulting in the pH value of the furnace water, PO 4 3- The pipe cutting inspection shows that there are acid phosphate deposits and local pitting on the pipe wall

In addition, during phosphate treatment, it is difficult to accurately measure the salinity level of the furnace water, and the concentration of chloride ions in the furnace water often occurs, and the chloride ion content reaches the milligram level at the highest level, which intensifies the corrosion of the furnace tube to a certain extent

When the full volatilization treatment is used, the pH of the furnace water is low, which will cause corrosion of the pipe wall

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