Q: I have two cooling towers utilizing softened water. It has 0 hardness after softening, pH is 8.Seventy five, conductivity is a hundred and fifty and alkalinity is 40, chlorides are 10. The one tower water has a pH of eight.2 within the sump in addition to 140 hardness, 514 conductivity, 30 chlorides and 180 alkalinity. The other tower has a pH of 7.84, hardness of 200, 549 conductivity, forty chlorides and 200 alkalinity. What is causing my hardness to be so excessive within the tower and am I wasting water. Also, do you’ve any concepts to improve my therapy. The towers each have rust on the inside walls, and we’re utilizing a therapy with sodium hydroxide in it.
A: The usage of softened water in cooling tower systems requires very particular therapy since softened water may be very corrosive to ferrous metals. You didn’t specify your treatment program, but following are my feedback. The iron construct-up in cooling tower indicates that corrosion is occurring within the system. Dissolved iron will oxidize because it falls by a cooling tower allowing precipitation of iron in fill and in basin. A corrosion inhibitor and iron dispersant will be required to stop corrosion and excess dissolved iron from the system. Notice: The quantity of iron that has already been deposited will require mechanical and/or chemical cleansing to take away.
You’re working at about 5 cycles of concentration based on alkalinity readings. The hardness in cooling tower is coming from an outdoor source, almost definitely wind blown mud from the ambiance. The amount of hardness in cooling tower cannot be predicted, so you simply have to take care of calcium/alkalinity balance to prevent precipitation of calcium carbonate. Your pH range is within normal limits for the calcium/alkalinity you’re at the moment maintaining.
I don’t imagine you’re wasting water, though you are on the decrease limit of regular range for cycles of concentration (5-7).
Cooling FAQs are offered by the Houston-primarily based Cooling Know-how Institute (CTI), a non-revenue organization devoted to enchancment in know-how, design, efficiency and maintenance of cooling towers and evaporative heat switch methods (EHTS). They’re from the “Ask the Expertcolumn of CTI Journal.