Improper boiler storage can lead to disruption of production

Appropriate storage techniques can be critical to maintaining boiler longevity. Our experience has shown that improper storage of a boiler can be detrimental to a boiler’s life, with corrosion on either the fire or water side occurring.

With this in mind, storage techniques are even more critical for steam generating boilers that are infrequently used as standby units or operated just during shutdown and maintenance periods.

Fireside corrosion can occur with a boiler in a cold state (standby). This is typical on boilers that have previously used sulphur enriched fuels to fire on. No matter how meticulously soot blowing operations are adhered to, remnants of combustion products will inevitably still be present within the gas side of the boiler. The interface where the tubes enter the drums, headers, baffle plates and at the interface between the water tubes and refractory are most susceptible to this form of corrosion.

This type of corrosion is generally not a problem when the boiler is operational (hot) as during operation the moisture from the furnace is removed due to the elevated temperatures that exist in the furnace space. However, upon shutdowns and scheduled maintenance periods, the residing combustion products (ash, oil residue) and the refractory can absorb moisture with localised pitting occurring over time.

Whenever possible, the boiler should be stored in a warm condition in order to prevent corrosion of the fireside. Warming storage techniques such as utilising the water drum’s heaters or routing the blowdown from an operating boiler through the inactive unit is generally sufficient to keep the temperature of the boiler tubes elevated and above the acid dew point.

Using these techniques for keeping a boiler warm are key to getting a boiler that is in standby state to an operational state with minimum disruption to production. It will also minimise improper start-up problems associated with warming up the boiler.

Finally, a boiler stored in warm state of standby with the boiler full of water, must be correctly managed to prevent oxygen corrosion.

To talk to our services team about avoiding improper boiler storage contact Neil Ford neilford@heatexchangegroup.co.uk