Power generation is one of the world’s largest industries, and demineralised water is critical to its success. Across boiler feedwater systems, the steam cycle and cooling processes, large volumes of high‑purity water are required to protect critical assets and maintain performance. If water quality does not meet the required standard, plants face increased corrosion, scaling and fouling, significantly reducing efficiency, reliability and equipment service life.
Today, as environmental pressures intensify, regulations evolve and operational costs continue to rise, plant efficiency is firmly under the spotlight. Technologies used to produce demineralised and ultrapure water must deliver consistently high performance and more. They must help optimise operations, control costs, and support sustainability goals.
The power of innovation
Producing demineralised and ultrapure water for power generation has traditionally been a complex, multi-stage process that involves filtration, water conditioning, bulk reduction of suspended solids and organics, degasification, and final polishing to remove ionized contaminants. The financial, environmental, and safety costs have been high. But not anymore. Advanced technology has changed the game, delivering safety, compliance, and efficiency, all while dramatically reducing OPEX.
Continuous electrodeionization (CEDI)
CEDI is the technology delivering next-level ultrapure water production. It replaces ion exchange resin beds and chemical regeneration with an electrochemical process that uses no hazardous substances. In the CEDI process, direct current applied to the feedwater stream drives positively and negatively charged ions through negative and positive ion exchange membranes, where they are captured and directed to the waste stream. What’s left behind is product water that can reach 18 megohm-cm resistance in purity—well within today’s tolerances for ultrapure boiler feedwater.
Xylem’s Ionpure® CEDI system was the first of its kind for industrial users. The VNX series has been specifically engineered to meet the needs of the power market, able to provide high flow rates from 15 up to 100 gpm. The system delivers higher throughput within a smaller footprint compared to traditional ion exchange, making it simple to upgrade to this advanced technology.
With CEDI systems, operators can secure an uninterrupted supply of superior quality, high-purity water while eliminating the safety risks posed by chemicals. They also reduce maintenance and cut water usage, as there’s no backwash required. Xylem’s CEDI systems are helping plants worldwide to redefine what is possible for the power industry to remain competitive, compliant, and resilient.
Ultraviolet (UV)
UV is a key technology in the production of ultrapure water. It reduces total organic carbon (TOC) in boiler feedwater for higher system performance. TOC is present in all untreated water and, if left, acts as a nutrient for microorganisms, which can result in large increases in bacteria. This can be hugely detrimental to boiler performance, leading to costly downtime and reduced service life. UV disinfection works by UV light disrupting the DNA of microorganisms, preventing their growth, while specific UV wavelengths break down trace organics. Xylem’s TOC range of ATG™ UV systems are highly efficient, cost-effective, and built for operational flexibility and performance.
Electrochlorination
To address marine biofouling and optimize cooling efficiency, electrochlorination is the leading water treatment solution. Biofouling in water intake and cooling systems can cause blockages, lower the overall efficiency of cooling systems, and reduce the service life of components. With Xylem’s Chloropac® systems, water is passed through electrolytic cells while a low-voltage direct current (DC) is applied before the resulting hypochlorite solution is injected into the water intake. It’s highly effective, continuous, safe, and low maintenance.
