What actions are required to prevent scale formation in the boiler?

Preventing scale formation in a boiler is essential for maintaining efficient heat transfer and preventing tube failures. Scale is a hard, insulating deposit that forms on boiler tubes due to the precipitation of dissolved minerals. Several actions are required to prevent scale formation. First, effective external water treatment is crucial. This involves removing hardness minerals, such as calcium and magnesium, from the feedwater before it enters the boiler. This can be achieved using water softening, reverse osmosis, or demineralization. Second, internal water treatment involves adding chemicals to the boiler water to prevent scale formation and corrosion. These chemicals include scale inhibitors, oxygen scavengers, and pH adjusters. Scale inhibitors prevent the precipitation of hardness minerals, while oxygen scavengers remove dissolved oxygen to prevent corrosion. pH adjusters maintain the water pH within the optimal range to minimize both scaling and corrosion. Third, maintaining proper boiler water chemistry is essential. This involves regularly monitoring and adjusting the levels of pH, alkalinity, conductivity, and dissolved solids in the boiler water. Fourth, implementing a blowdown program removes accumulated solids and impurities from the boiler water, preventing them from reaching concentrations that promote scale formation. Both continuous and intermittent blowdown are used. Fifth, minimizing feedwater contamination reduces the amount of impurities entering the boiler. This involves preventing oil, grease, and other contaminants from entering the feedwater system. Sixth, regular inspection and cleaning of the boiler tubes removes any scale deposits that do form. This can be achieved using chemical cleaning or mechanical cleaning methods. Regularly performing these actions minimizes scale formation, improves boiler efficiency, and extends the lifespan of the boiler.