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News & Views, Volume 49 | Attemperator Monitoring with Wireless Sensors - Risk and Cost Reduction in Real Time

News & Views, Volume 49 | Attemperator Monitoring with Wireless Sensors: Risk and Cost Reduction in Real Time

News & Views, Volume 49 | Attemperator Monitoring with Wireless Sensors - Risk and Cost Reduction in Real TimeBy: Jason Van Velsor, Matt Freeman and Ben Ruchte

Installed sensors and continuous online monitoring are revolutionizing how power plants manage assets and risk by facilitating the transformation to condition-based maintenance routines. With access to near real-time data, condition assessments, and operating trends, operators have the opportunity to safely and intelligently reduce operations and maintenance costs and outage durations, maximize component lifecycles and uptime, and improve overall operating efficiency.

But not all data is created equal and determining what to monitor, where to monitor, selecting appropriate sensors, and determining data frequency are all critical decisions that impact data value. Furthermore, sensor procurement, installation services, data historian/storage, and data analysis are often provided by separate entities, which can lead to implementation challenges and disruptions to efficient data flow.

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News & View, Volume 43 | Attemperator Damage Prevention A Case Study Using Online Monitoring

News & Views, Volume 43 | Attemperator Damage Prevention A Case Study Using Online Monitoring

By:  Fred DeGrooth and Ulrich Woerz

News & View, Volume 43 | Attemperator Damage Prevention A Case Study Using Online MonitoringAttemperators (aka desuperheaters) are used in fossil and combined cycle plants to protect boiler/HRSG components and steam turbines from temperature transients that occur during startup or load changes. The attemperator sprays water droplets into the superheated steam to ensure that the downstream, mixed, steam temperature will not adversely affect downstream components.  While there are a number of attemperator designs and configurations (Figure 1 shows a schematic of a typical arrangement), all of them are potentially vulnerable to damage, making attemperators one of the most problematic components – particularly in combined cycle plants. If the causes of damage are not identified (and addressed) early, then cracking and steam leaks can occur leading to costly repairs and replacements. 

The frequent cycling and wide operating range of combined cycle plants impose particular demands on attemperator functionality.  Spraywater demand to the attemperator can fluctuate greatly within a startup where heat input to the boiler and steam flow are changing rapidly.  At part load operation spraywater may be required continuously to moderate steam temperatures because of high exhaust gas temperature from the combustion turbine.  Spraywater may also be demanded when duct burners are fired. 

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