Good Water Treatment Systems Need Both Equipment and Chemistry.
Proper water treatment is vital to successful power plant operation. The water treatment system must be designed appropriately, implementing a suitable water chemistry program, and operated and monitored correctly. Having adequate training and utilizing the services of a knowledgeable partner can be invaluable.
Three water industry experts from U.S. Water, a Kurita company, were recent guests on The POWER Podcast. Kevin Milici, vice president of Marketing and Technology; Nathan Bach, vice president of Engineering Services and Equipment, and Joe Tirreno, vice president of Strategic Corporate Accounts shared insight from their years of experience helping customers develop sound water treatment solutions.
Bach noted that many older power plants are shifting from primary ion exchange, that is, cation-anion mixed beds, to membrane treatment systems for their demineralized water needs. Meanwhile, some that may have had older-generation membrane treatment systems, such as reverse osmosis (RO) and electrodeionization (EDI) systems, have been upgrading to include ultrafilters ahead of the RO to reduce fouling and extend membrane life or utilizing two-pass RO units to reduce the loading on EDIs.
A lot of things must be studied when designing a water treatment system for a power plant. Bach said boiler operating pressure is one of the first considerations, but the raw water source is also very important. “A plant that operates on well water will have different challenges than one that operates on surface water or maybe even a plant that has multi-source—maybe they have a blend of surface and well water or multiple wells of different depths blending into a common feed point into the plant,” Bach said. “Knowing where the water comes from really helps us determine how we might need to treat it.”
Tirreno said two of the most important items in a power plant are steam quality and condenser cleanliness. He noted that most plants spend significant amounts of money to monitor steam quality, but they don’t always do the same on the condenser side. He said monitoring equipment is available today that allows biofilm and corrosion to be more instantaneously scrutinized. “The steam side is important,” Tirreno said, “but don’t forget the condenser side as equally as important to ensuring efficiency of electricity generation.”
“The takeaway is that we can’t just think of it in terms of chemistry or equipment, we have to think of the combination of those things,” Milici said. “Every situation can be unique. It’s a function of the customer’s assets, their design, the water qualities that they’re working with, the other challenges they might be confronted with, for example, water scarcity or the discharge of conventional phosphate-bearing treatments and having to minimize those and look for alternative chemistries. So, my takeaway would be that it’s not one or the other, it’s the ability to be able to look at both of those levers in looking at the total solution and put them together in the right proportions to deliver the best and most cost-effective result.”