Plan a boiler lining repair before the planned shutdown, so as not to select the material only after dismantling the device. Data on the existing lining, location of damage, and operating conditions are needed. A small visible defect does not always mean a small repair scope, especially when a larger part of the lining has loosened underneath.
Collect data on the damage
Perform the inspection after shutting down, isolating, and cooling the boiler according to its operating procedure. Record the location of the defect, approximate depth, condition of the edges, and support points. Take a photo of the entire area as well as a close-up with a scale.
Add fuel or process, start-up frequency, and previous repair history to the description. Information that the same fragment falls off every season helps in investigating the cause in the mounting, working conditions, or material incompatibility.
Choose the material by the lining layer’s function
Refractory concrete Vitcas 1600STD is an example of material for specific linings. However, it should not be chosen for every boiler solely because of its temperature class. Thickness, mechanical load, working environment, and compatibility with existing material are also important.
A compound such as BLACK Fire Cement, corresponds to other tasks: selected minor repairs and rigid joints. It will not automatically reproduce thick monolithic lining, its anchors, or supports.
Include time after application in the schedule.
The downtime plan should include an assessment after exposing the site, surface preparation, installation, and required material curing. Then, the moisture removal and initial heating process appropriate for the repair is needed.
Do not transfer water ratios or heating schedule from another refractory concrete. They depend on the specific mix and the thickness of the lining. Determine these conditions with the material supplier and equipment service before setting the restart date.
After the repair, keep the name and batch of the product, photos, and a record of the steps performed. During the next inspection, it will be possible to compare the durability of the repaired area and check whether the problem has not spread to the adjacent connection.