What are the reasons for the high phosphate concentration and low pH value of the drum water?
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For the water in our boiler’s drum, the phosphate level is kept between 5 and 15, but the pH value is only around 8, which is below the specified level of around 9. Why? According to theoretical calculations, when the phosphate concentration is at 10, the pH of the drum water can reach 9. I don’t understand why we can’t achieve this level; could anyone please explain it? Chloride levels are also not high.
Keep the phosphate level between 5 and 15 – should it be set at 15?
Sodium triphosphate is added to the drum water; the phosphate concentration is around 10 mg/L. I meant the phosphate concentration – I didn’t specify the unit; my apologies. Currently, the concentration of phosphate in the drum water is only 8.
Our figure is 8-8.5; I wonder why yours is so high
It’s not high; we use the same indicator as well
What type of steam drum do you have, low-pressure or medium-pressure? For medium-pressure steam drums, the pH value is controlled between 9 and 11
Add some lye when preparing the solution to raise the pH value a bit.
Medium pressure, with a pressure of around 4.5
Then your pH value won’t be kept that low
Our conditions are the opposite: pH of 9.5–10, phosphate level of 4–6, and conductivity of 10–25. We want to increase the phosphate level but are unable to do so, and we don’t know why.