Water treatment evaluations and audits
A power station can continue operation without problems only if it is operated with water of sufficiently high quality. We can help the customers to make sure that this prerequisite is fulfilled for example by reviewing the results from the measurement and analyses done by the customer’s personal, collecting and analyzing water and steam samples, and performing our own measurements and analyses on site. We can also audit the water treatment systems and water quality monitoring.
We carry out annually a benchmarking exercise, in which water and steam samples are collected from several power stations and analyzed comprehensively.
All participants receive a plant-specific report, in which their results are reviewed in detail, and a summary report containing all results from all participants. The benchmarking results will clearly demonstrate any severe deviations in water and steam quality. The results have been successfully used in early detection of corrosion and scaling problems and, in cases where the customers have not been convinced by the results early enough, in the identification of root causes for later problems.
We carry out internal inspections, in which both steam generator tube wall thicknesses and internal scale thicknesses are measured using an advanced ultrasound technique. Compared with the traditional method, in which one or two tube samples are cut and analyzed, our method provides the following benefits:
- internal scales can be measured in several hundred locations in few days, so the results give much better picture of the boiler tube condition
- the advanced ultrasound technique is non-destructive, no new welds are needed
In practice both methods are used often together so that the advanced ultrasound technique is used first. If the results indicate that significant scaling has taken place in certain locations then tube samples are taken so that the composition of the scale can be analyzed in more detail. However, if the ultrasound measurements indicate that the scales are thin in all tubes then tube sampling can be completely avoided. If the internal inspections indicate that some corrosion or scaling is taking place, the analysis can be continued with a complete review of water quality data and the identification of corrective actions in water treatment.
Supervision of acid cleanings
Internal surfaces in boilers are cleaned by acid treatment, when a new boiler is commissioned and when internal scale thickness is becoming so large that tube material temperatures are increasing too high.
Varo’s experts have a wide experience from different acid cleaning methods. We can supervise that acid cleanings are performed safely and effectively so that boiler is clean after the treatment and well-protected against corrosion and scaling. We can confirm that acid treatment is effective by measuring scale thicknesses during acid cleaning treatment or performing a full scale internal inspection after the acid cleaning. We can also help the customer to treat acid cleaning waste safely and economically.