The pH of the boiler water is low
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The pH of the boiler water is low, around 9. Can sodium hydroxide be used to adjust the pH? Are there any specific requirements regarding the amount to be added?
It is preferable not to adjust the pH of boiler water using sodium hydroxide; instead, trisodium phosphate is a better choice. Firstly, it allows for a gradual adjustment of alkalinity, and secondly, it is itself a water treatment agent
Why should sodium hydroxide be avoided as much as possible? What are the hazards?
The boiler water can be adjusted using sodium hydroxide + trisodium phosphate. If only trisodium phosphate is used for adjustment, once the pH reaches the desired level, the phosphate concentration may become too high, leading to the formation of harder salts such as magnesium phosphate and calcium phosphate in the furnace water.
If the phosphate level in the boiler water is within the specified range but the pH is low, sodium hydroxide needs to be added to adjust the pH value! Under normal operation, trisodium phosphate is added to keep phosphates and pH within the specified range!