Powering Performance with an Integrated Approach to Cooling Water

Power plant managers know that optimizing cooling water operations will improve efficiency. Using an integrated approach that combines advanced chemistry, digital technologies, such as deposit sensing, and data analytics to detect issues early can enhance system performance and potentially increase power output while reducing maintenance costs and environmental impact.

The power industry faces growing demand for reliable and affordable energy. Fueled by electrification trends and surging data center growth, increasing demand requires power plants to adopt innovative strategies so they can continue to provide uninterrupted service.

Power plants rely on consistent cooling water processes to operate. Scale, corrosion, fouling, and microbiological growth can significantly impact cooling water efficiency and reliability, affecting the lifespan of critical equipment and infrastructure. Without an optimized treatment program, plant operators must plan for long maintenance windows and downtime to address scale deposits and other issues.

To respond, power plants must take an integrated approach to manage cooling water operations. By combining advanced chemistry with digitally enabled solutions like deposit sensing technology and intelligence, operators can maintain optimized cooling water systems for consistent performance.

Applying Deposit Sensing Technology

Nalco Water, an Ecolab company, applied an integrated cooling water program to help an aging Louisiana power plant maintain efficient operations. The 585-MW plant had recently changed its water source from surface water to groundwater, which threatened to impact production. Unlike surface water, groundwater contains higher concentrations of iron, manganese, silica, and microbial constituents. These scale-forming elements and microbial concentrations can significantly impair the efficiency of condensers and heat exchangers, posing a critical challenge for the plant.

The plant’s engineering group worked alongside Nalco Water (Figure 1) to address the challenge. Together, the team implemented a program that combined water management solutions with advanced deposit-sensing technology. By implementing the program, engineers aimed to establish early detection of fouling events that could impact production.

1. A service engineer and customer walk through a plant. Courtesy: Nalco Water

As a key component of the program, Nalco Water leveraged 3D TRASAR Technology for Cooling Water. The solution uses automation to detect variability, determine the appropriate corrective action, and deliver optimized chemical treatment. Further, the solution contains deposit-sensing technology that uses an innovative measurement process to help operators identify scale deposits in real time, measuring key stress parameters to detect changes and provide early warning of scaling, corrosion, and biofilm deposits.

The deposit-sensing technology uses an array of resistance temperature devices that mimic the different temperature levels on the skin of a heat exchanger. This allows the sensor to provide early indication of fouling risk, while also identifying the type of deposit likely to form. The sensor also allowed the plant to collect vital performance data. By coupling the information with other 3D TRASAR controller data and contextualizing it through digital services powered by the ECOLAB3D platform, Nalco Water provided the power plant with insights to respond to potential deposits in real time.

With the new program in place, the power plant reported its first early indication of a potential performance issue. The event resulted from suspended solids that had been released into the bulk water during a recent plant startup. Later, the deposit-sensing technology reported a second rapid deposition event. Upon investigating the situation, the power plant and Nalco Water service engineers (Figure 2) determined that higher iron and silica concentrations in the new makeup water source, combined with poor control of cooling tower cycles of concentration and loss of dispersant feed, contributed to the deposition event.

2. A field service associate completes an inspection. Courtesy: Nalco Water

Subsequent deposit analysis confirmed what the Nalco Water technology had predicted: an iron-silica scale caused by elevated levels of contaminants associated with the recent startup and the new well-water source. The data collected, transmitted, and analyzed by the Nalco Water team helped the plant engineering staff understand how this event happened and recommend corrective actions to prevent its recurrence. By using a holistic approach to analyze the insights, Nalco Water identified a potential value of $3.3 million in improved productivity and reduced maintenance costs, if the plant implemented critical improvements.

Using Digital Intelligence to Increase Power Plant Output

In another example, Nalco Water used digital intelligence to help a combined cycle power plant increase megawatt output. Based in Thailand, the 125-MW plant contributes electricity to a local power grid, as well as steam to industrial businesses. The plant consists of two identical blocks, using natural gas as fuel. Like most combined cycle units, the plant’s surface condensers are central to its production efficiency, needing to operate as designed to maximize profitability, minimize fuel costs, and reduce greenhouse gas emissions.

Plant operators contacted Nalco Water to conduct an extensive plant survey. While conducting the survey, engineers found a discrepancy in vacuum pressure between two condensers, despite similar operational conditions. The difference between the condensers resulted in backpressure penalties that adversely affected heat rate and power output—leading to decreased revenue and increased operational costs for the plant. Nalco Water introduced a digital solution, OMNI Condenser Intelligence, powered by ECOLAB3D, to evaluate the performance of each condenser and pinpoint the underlying issues.

The issue was found to be in the vacuum pump system of the condenser. The plant maintained two vacuum pumps, one operating and one on standby. Nalco Water noticed that one of the vacuum pumps caused more backpressure than the other. Based on the insights generated from the pumps, the plant conducted a two-month trial, exclusively using the pump that caused less backpressure. Nalco Water used OMNI Condenser Intelligence to monitor and analyze performance, and to quantify the impact of the change.

Through the trial, the plant and Nalco Water concluded that the vacuum with more backpressure caused performance degradation when in use. Specifically, the analysis indicated that the average backpressure penalty was reduced by 0.5 kiloPascal absolute (kPa) during both off-peak (70% load) and on-peak (full load) operations, as illustrated in Table 1.

Table 1. Backpressure can adversely affect heat rate and power output, leading to decreased revenue and increased operational costs for a plant. Backpressure values (in Kilopascal [kPa]) are shown in this table before and after a vacuum pump problem was corrected at a plant in Thailand. Source: Nalco Water

Nalco Water collaborated with the plant efficiency engineer to estimate the actual megawatt increase during the trial for both on-peak and off-peak periods. Based on their calculations, the team estimated that the plant could increase output by 1,100 MW per year, equivalent to $91,000 annually in increased revenue.

The Power of an All-Encompassing Approach

Nalco Water approaches cooling water operations with the end-to-end experience in mind. By looking holistically at plant processes, the company can help manage performance and support key business drivers, like sustainability. To bring together innovations like enhanced automation, sensing, and intelligence, and pair them with innovative chemistry treatments, Nalco Water recently launched the Premium Cooling Water Program. The program takes an integrated approach to help power plants optimizing cooling water operations, addressing water quality and scale control through the following:

• Real-Time and Predictive Asset Intelligence. Available for multiple types of assets, like heat exchangers, condensers, air separation units, and steel contact systems, Nalco Water’s digital solutions help protect asset life and maximize system uptime. Using historical and real-time data from multiple sources, and leveraging predictive analytics, the solutions help operators identify and address potential mechanical, operational, and chemical issues early to minimize unplanned downtime and maintenance.
• Automation and Deposit Sensing Technology. Nalco Water uses automation to detect cooling water variability and determine potential corrective actions to deliver optimized water treatment. The system features an enhanced all-in-one controller with a touchscreen user interface and deposit sensing technology. The system also connects to the Ecolab Global Intelligence Center, a network of remote monitoring specialists who provide 24/7/365 support at six intelligence centers worldwide.
• Premium Chemistry Products for Scale and Corrosion Control. Nalco Water offers a variety of low-phosphorous and non-metal products formulated to help optimize operations while also complying with regulations. The solutions help operators balance performance with sustainability by contributing to less phosphate and metal discharge into the environment.

By combining automation and predictive insights with innovation and a global expert ecosystem of engineers and service specialists, Nalco Water aims to help increase system uptime, reduce water and energy use, and maximize productivity. “As industries worldwide face pressure to maintain cost-effective performance while moving toward sustainability targets, our Premium Cooling Water Program emerges as a crucial solution that can help customers prioritize both,” said Jeff Bulischeck, executive vice president and general manager of Global Heavy Water at Nalco Water. “Through this program, Nalco Water can deliver comprehensive customer value enabled by best-in-class digital technology and expertise.”

—Chad Williams is director of Marketing, Global Power for  Nalco Water, an Ecolab company.