Internal Cleaning of Water-Tube Steam Generating Plants and Associated Pipework - Print

In the power plant industry numerous company-specific or proprietary guidelines and specifications for internal cleaning and steam blowing exist. Nevertheless, misunderstandings and omissions repeatedly occur which in extreme cases may lead to severe steam boiler and turbine damage.

The Annexes, chapter 10.7 contains literature examples taken from the journal VGB PowerTech (formerly VGB-Kraftwerkstechnik) to inform users of this guideline on the close relationship between the selection of a cleaning procedure as well as the correct mode of operation and water-steam quality, and the economic efficiency and safe operation of a plant.

This VGB-Standard is intended to give recommendations for:

• flushing
• alkaline boil-out
• pre-operational acid cleaning of new plants
• chemical cleaning of plants under operation
• steam blowing of water-tube generating plants and associated pipework upstream to the turbine, where required
• combination of pre-operational acid cleaning and steam blowing as coherent process

Each or a combination of these cleaning procedures may be applied which will depend on the plant fouling condition. Cleaning procedures should be performed shortly prior to hot commissioning so that the results of successful cleaning are not impaired. The VGB-Standard shall apply to the cleaning of newly erected steam boiler plants and associated pipework, but, where required, e.g. after longer operational periods, it shall also apply to major repairs and inspections as well as in the case of other occurrences.