Operational chemical cleaning normally means to clean a boiler that has been in operation. The need of a chemical cleaning depends on several factors. Just one factor is usually not crucial and the appropriate time for a chemical cleaning shall be assessed on a case-by-case-basis.

Decisions regarding chemical cleaning shall be based on the chemical composition and thickness of the deposits and the operation time since the last chemical cleaning. Observations from the latest inspection and tube samples shall also be considered. The main reason to remove deposits is because they significantly reduce the heat transfer and thereby the cooling of the tube material leading to greater risk of failure.

The result of a successful chemical cleaning, with the subsequent start-up of the boiler, will lead to a clean boiler with a thin compact and protective oxide layer. In addition, all parameters for water and steam quality will reach desired levels within the shortest possible time.

After a chemical cleaning it is important to start-up the boiler with careful control of the water chemistry and other operation conditions. A successful chemical cleaning followed by a start-up that is performed under incorrect conditions can lead to a situation where the goal for the chemical cleaning is not achieved.

Wistrand generally perform chemical cleaning according to the standard VGB-S-513-00-2014-07-EN Internal Cleaning of Water-Tube Steam Generating Plants and Associated Pipework, modified according to local conditions.

In addition to the implementation and execution of the cleaning Wistrand also provides consultations within the field of chemical cleaning.