Does your mill/plant monitor boiler tube waterside deposition using Deposit Weight Density (DWD) testing? Where do you take this tube sample from? Are you taking the sample from the best location? Valmet has a new tool designed to measure and record the thickness of internal boiler tube deposit layers and the remaining tube wall thickness in waterwall tubing. This hardware utilizes existing ultrasonic technology and proprietary software to accurately measure the tube thickness and the thickness of the deposit layer. This system allows for a more accurate chemical cleaning strategy, therefore reducing chemical cleanings and helping to extend the lifespan of your boiler. This technology can also monitor the removal of the deposit layer during the cleaning cycle.
There are numerous benefits to this approach, most notably the ability to measure tube scale deposit thickness with a direct correlation to the standard Deposit Weight Density method. In addition, tube samples are taken only when they are needed, where they are needed; when scale growth is monitored regularly, corrective actions can be taken before corrosion risks increase.
This equipment can be used to monitor the effectiveness of cleanings and can minimize the damage that can occur from excessive cleaning. Using the results from the Ultrasonic testing, boiler operators can replace the tubes that have issues, rather than acid cleaning the entire boiler. Acid cleaning would result in longer downtime and could damage otherwise good tubes.