Clean Water Key to Delivering Reliable Power to Canadian Residents

Posted: Monday 3rd November 2014

FILMTEC™ ECO Reverse Osmosis Elements Help Keep an Alberta Power Station Operational Despite Challenging Source Water.

High-quality water is of paramount importance to power generation. It helps facilitate efficient and reliable operations, protect c­­ritical equipment, and minimize environmental impact. Source water for many power plants, however, is far from ideal. That is certainly the case for a power station in Alberta, where an innovative two-pass reverse osmosis (RO) design was used to optimize the plant’s existing configuration. The design includes DOW FILMTEC™ ECO 440i Reverse Osmosis elements and DOW FILMTEC™ XFRLE-400/34i Reverse Osmosis elements. Since their installation, FILMTEC ECO elements have resulted in 30 percent more energy savings in the system’s second pass and FILMTEC XFRLE has improved overall pressure drops and fouling.

The lake source water at the power station is derived from a combination of the North Saskatchewan River, mine drainage, plant site drainage, sewage effluent and chemical neutralization ponds. Due to the highly variable nature of source water, the system requires thicker feed spacer elements to reduce fouling rates, and to lower the pressure drop in the first pass.

“To combat this water source challenge, we designed a two-pass RO system with state-of-the-art FILMTEC XFRLE elements for the first pass and FILMTEC ECO 440i elements for the second pass,” said Denise Haukkala, technical service, Dow Water & Process Solutions.

Together, these low energy elements provide a solution to treat the power station’s high-fouling source water, and deliver high-quality permeate for the boiler feed process. FILMTEC ECO and FILMTEC XFRLE elements are optimized with low pressure drop feed spacers to allow for lower feed operating pressures, which help reduce operating costs and counter the effects of the cool feed water temperature range (7-26°C). FILMTEC ECO elements have also helped reduce chemical usage, when the plant opted not to degas the carbon dioxide with caustic in the second pass, while maintaining high permeate quality for continuous electrodeionization (CEDI) polishing prior to feeding the boiler.

Power plants rely on a steady stream of water to convert heat energy into electrical energy to drive the turbines that run the electric generators. To accomplish this, the plants require high-quality feedwater to operate their boiler and cooling system. The treatment of boiler feedwater is extremely critical, as problems can result from the use of untreated water in extreme pressure and temperature environments, including lower efficiency, overheating, damage, and the need for frequent cleaning. Since 95 percent of water used in plant operations can be reused, it is vital that both the feedwater and recycled steams are effectively treated to prevent scale and corrosion in the steam water circuit.

“Highly variable source water and cooler feed temperatures can present unique energy and fouling challenges for Canadian power plants,” remarks Wendy Rae, account manager, Dow Water & Process Solutions. “We are proud to provide early adopters of innovative technology with solutions to help lower their operating costs, reduce plant downtime, and maintain product water quality and consistency.”

Recognizing the perilous state of water demand, FILMTEC ECO elements’ unique configuration offers the possibility of higher rejection of salts at significantly reduced operating pressures, helping deliver up to 40 percent better water purification while using up to 30 percent less energy, resulting in up to 19 percent lower operating costs. FILMTEC ECO membrane technology recently won a prestigious Edison Award for its innovation and contribution to combat global water scarcity. The new technology was also named Dow’s second-ever Breakthrough to a World Challenge as part of the Company’s 2015 Sustainability Goals.

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April 2021

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