Reasons for the low PH of the drum water
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Recently, the pH level of the water in our boilers has been low. Can adding sodium phosphate raise the pH? Additionally, excessive waste discharge by some people can also lead to a low pH level. Why? Seeking advice, thank you
1. Adding phosphates does not increase the pH of boiler water. The purpose of adding phosphates is to convert insoluble, scale-forming substances such as calcium carbonate into loose calcium phosphate, which can then be removed through blowdown. It is still necessary to adjust the boiler water by adjusting the pH of the feedwater. 2. The pH of the general feedwater is typically maintained at around 8.5; through the evaporation and concentration of the boiler water, its pH is kept between 9 and 10.5. Frequent blowdown will inevitably reduce the degree of concentration of the boiler water, thereby lowering its pH.
Adding sodium hydroxide can increase the pH value
Check the pH value at the outlet of the desalinated water unit, and examine each section starting from the source; it is necessary to identify the cause, as a low pH level of the boiler water can cause severe damage to the boiler
It has little to do with trisodium salt and wastewater discharge
If the pH of the boiler water is low, the first step should be to increase the pH of the feed water. Trisodium phosphate can be used to raise the pH, but its effect is limited; first, it is necessary to ensure that the phosphate level does not exceed the allowed limits.
Traditionally, the pH value of boiler water is adjusted using phosphates. The first thing to determine is what the steam pressure of your boiler is; depending on that steam pressure, the pH value of the boiler water also varies. Generally, the pH level of the boiler water is kept between 9 and 11; of course, it can also be maintained between 9 and 12. As you mentioned, the pH level of the boiler water in your case is on the low side. Search from the following aspects: (1) Whether the pH value of the feed water meets the standards, whether there are microorganisms present, and whether the COD level is within limits; check this by examining the ion exchange process at the desalination station ； Also, check the COD of the steam condensate that enters the boiler; if it is too high, it can affect the pH value as well. (2) Whether the chemical itself has lost its effectiveness, and whether its concentration meets the required standards. (3) What is your phosphate level, and does it meet the national standard requirements? Generally, it is 5-20 mg/L. Reducing wastewater discharge is only a temporary solution, not a fundamental one. (4) If the pH value continues to drop, the top priority is to add some caustic soda to raise it. (5) Is the amount of pesticide applied normal?