Can the water used to replenish the cooling circulating water be soft water?
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Design temperature for the open-loop cooling circulating water: 32°C → 37°C, with a circulation volume of 2200 m3/h. Initially, the water used for replenishment was industrial water; now we are considering changing it to soft water. I wonder if that is possible? ? (1) Industrial water contains high levels of calcium and magnesium ions as well as high conductivity; can the amount of scale inhibitors and other chemicals required be reduced by using soft water instead? (2) The COD level of industrial water is high; after concentration through recirculated water, it exceeds the discharge standards, so it is desired to convert it to soft water. (3) What kind of water is used for topping up the cooling towers at various Haiyou facilities?
It’s just ordinary water, very dirty; a scale inhibitor needs to be added
Soft water is certainly an option; the main issue is the cost of using soft water
Generally, water is used only once; soft water has calcium and magnesium ion levels below 3 ppm. When using soft water to replenish the circulating water, it is necessary to measure the change in total phosphorus content in the water before and after adding the scale inhibitor, in order to determine the appropriate dosage
Cost is not considered for now; there is a surplus. It’s not clear whether this will work from a technical standpoint; what impact will the addition of soft water have on the circulating water system?
We, as manufacturers of cooling water chemicals, are not allowed to use soft water, and they don’t explain why; we don’t understand the reason
How much does it cost to use soft water for water drawn directly from the well?
If you have plenty of soft water available, then of course soft water is better. It is only necessary to properly control the dosage of various chemicals added to the circulating water; the approaches for managing circulating water differ when using soft water versus once-used water.
There is a gauge that monitors and automatically controls the dosage of the chemicals added to the circulating water. Is it necessary to change this control method?
It’s not a change in the control method; it’s a change in the formula and the amount of chemicals used, etc. The use of soft water increases the corrosivity tendency of circulating water while reducing its scaling tendency. At that time, you will need to keep the pH value of the circulating water at a higher level (it should be above 9.0). The amount of dispersants and scale inhibitors used will need to be reduced, while the amount of various corrosion inhibitors used will need to be increased. Pharmaceutical manufacturers generally will not agree, unless a new contract is signed. Dispersants are not expensive, but corrosion inhibitors are relatively costly, especially copper corrosion inhibitors; the price difference is as much as fifty to sixty times.