Boiler Make-Up Water Treatment

The following chapter shall provide a brief overview of boiler make-up water treatment and conditioning. The treatment differs from case to case depending on the initial and required water quality. Overall, treatment is focused on the removal of suspended solids, TDS, silica, hardness, and dissolved gases. As a result, commonly involved technologies are clarification, filtration, reverse osmosis, ion exchange, and, in some cases, electrodeionization. Dissolved gases are removed via stripping or deaeration. The rule of thumb indicates that higher boiler pressures demand a higher water quality. Therefore, treatment can reach from simple softening to total demineralization. Conditioning of boiler make-up water is accomplished with alkaline agents or dissolved oxygen, thus providing long-term protection against corrosion of the boiler material. The production of high-quality boiler make-up is further illustrated with an exemplary case study. The amount of boiler blowdown to be removed and TDS concentration in the boiler after a certain operation time can be estimated with different formulas.