Water

In the U.S. and the European Union, scrubbers are installed on all new coal-fired power plants because their technology is considered the best available for removing SO2. A zero-liquid-discharge system is the best technology for treating wet scrubber wastewater. With the future promising stricter limits on power plants’ water use, ZLD systems that concentrate scrubber purge streams are sure to become as common as ZLD cooling tower blowdown systems.

The Energy Information Administration estimates that U.S. thermoelectric generating capacity will grow from 709 GW in 2005 to 862 GW in 2030 to help meet annual demand increases of 2%. The makeup and cooling water needed by plants generating that increased capacity certainly won’t be available from withdrawal sources, so plant developers and owners will have to apply water-stingy technologies plantwide. As is usually the case, conservation saves money as well as the environment. Here’s a thumbnail economic analysis of some solutions to the water problem.

Stator cooling water treatment is often ignored—until the generator fails. Proper treatment and monitoring is essential to keeping the copper in your stators, where it belongs.

Replace pumps, cut repair bills / New bolts show their stress level / Up a certain creek, without a filter / Hang up those cables and hoses

The infrequent or improper introduction of biocides into a plant cooling system may make fouling within it worse, by creating thick biofilms that can foster corrosion, reduce heat transfer, and increase water pumps’ operating costs. At the other end of the spectrum, overuse of biocides can waste expensive chemicals. Optimizing the quantity, frequency, and type of dosage can improve both the health of a cooling system and its plant’s bottom line.

Because water is more precious than power in many regions of the U.S., plant designers are more frequently specifying the use of treated wastewater for plant cooling. Using "gray water" poses its own challenges for critical service equipment like condensers and heat exchangers. Some problems—like corrosion—are familiar, whereas others are rare. But so far, none has been a match for the ingenuity of multidisciplinary design experts.

Thermal power plants are required to use fish protection technologies or make changes in plant operation to protect aquatic organisms. We intuitively understand that some organisms in the water drawn in to cool a power plant can be injured or killed when they hit a screen or enter the circulating water system. You have options for compliance with EPA rules; some are extremely expensive and burdensome, whereas others are brilliant in their simplicity. This article debunks several fish impingement myths and gives practical advice for successful compliance.

The term "water hammer" encompasses a handful of hydraulic and thermohydraulic mechanisms. They include water hammer in steam and water piping, water piston, water induction, flash condensation and evaporation, and shock waves generated by transonic flow. All can lead to failures of steam and water cycle components and put plant operators and workers at risk. Proper design and O&M practices can keep water hammer and similar phenomena under control.

Ongoing maintenance is critical to the performance and longevity of underwater structures such as cooling water intake tunnels. Commercial divers or robotic vehicles can do the needed inspections, but such manual methods require a costly plant shutdown and provide only qualitative results. ASI Group Ltd. has designed and built an advanced, dual-axis sonar system that works in fast-moving water and can deliver quantitative data about the extent and location of debris buildup on submerged assets.

Among utility chemists, opinions differ on the effect that organic compounds—both naturally occurring types and those added as treatment chemicals—have on the steam cycle. Some chemists raise the specter of corrosion of low-pressure turbines caused by organic acids created as the compounds degrade. Others defend and encourage the use of organic treatment chemicals, particularly neutralizing amines, by pointing to a long and positive history of their use in boiler and feedwater systems.