Nondestructive measurement of boiler tube scale deposit thickness

Feb 2, 2016

Scale like this is minimized with Valmet's measurement program.Excessive scale deposit on boiler tubes results in costly energy losses and excessive boiler unavailability.  A well planned and executed boiler chemistry control program is essential to prevent tube failure. Valmet's Boiler Tube Scale Deposit Measurement Program is an effective inspection service that will enhance your program and help us better understand the deposition within your boiler.

Nondestructive measurement of scale deposit

Valmet engineers take multiple ultrasonic readings of the boiler tubes.

Valmet introduces a boiler tube inspection service designed to measure and record the thickness of internal boiler tube deposit layers in boiler waterwall tubing. The inspection service is performed using ultrasonic technology and proprietary software to accurately measure the thickness of the deposit layer.

The ability to measure boiler tube scale deposits allows for a more accurate chemical cleaning strategy - chemical cleaning cycles could be extended and the lifespan of your boiler can be improved. This Valmet service includes the ability to 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 (DWD) method. Internal scales in furnace tubes can be measured in hundreds of points, as compared to one point for standard DWD analysis. In addition, tube samples are taken only when and where they are needed. When scale growth is regularly monitored, corrective actions can be taken before corrosion risks increase.

Graphic displays of the ultrasonic wave shape accurately display the scale thicknesses.

Graphic displays of the ultrasonic wave shapes accurately display the scale thicknesses.

Valmet can monitor the effectiveness of cleanings and, if cleanings are improperly performed, can minimize the damage that could 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 if improperly performed. On-line monitoring of acid cleaning means the acid treatment phase can be extended or terminated as needed. Cleaning results can be verified (vs. guarantees).

Contact your Valmet representative to learn how the boiler tube scale deposit measurement service, using nondestructive ultrasonic testing, can benefit your operation.