A common function of Economizers in power plants is to capture the waste heat from the boiler stack (flue gases) and transfer it to the boiler feedwater. This then raises the temperature of the boiler feedwater, lowering the subsequent energy required and in turn reducing the firing rates needed for the rated boiler output.
Economizers lower stack temperatures, which may cause condensation of acidic combustion gases and lead to premature equipment corrosion if care is not taken in material selection and design. In addition, dependant on the humidity of the fume gases and combined with any solid or semi solid residues, clogging and blocking of the fins may occur. Compared to regular economizer tubes, finned econimzer tubes offer an enhanced heat tranfer surface at same dimensions.
The application of SÄKAPHEN coatings for corrosion protection against flue gases on Economizer tubes allows the Design Engineer to use finned tubes to offer further surface area and aid cooling per unit, safe in the knowledge that SÄKAPHEN provides full coverage and protection, especially on the fin tips, which are almost impossible to coat with other technologies.
One of the main advantages of applying SÄKAPHEN heat cured linings and coatings to Economizers and other Finned Tubed Heat Exchangers as found in non-leakage Gas Gas Heaters (GGH) is the excellent resistance to Hydrofluoric Acid (HF) and Sulfuric Acid (H2SO4) at concentrations as found in fume gases at operating temperatures. SÄKAPHEN also offers enhanced resistance up to 200°C for fume gases and critically above and below the dew point when condensation of acidic fumes occurs. Depending on the lining or coating specified, SÄKAPHEN linings and coatings offer enhanced protection against abrasion caused by ashes in the flue gas stream.
Further to protecting Finned Tube Heat Exchangers, SÄKAPHEN protects Air Coolers, HVAC and HVAC-R equipment with its superior coating solution, be it onshore and offshore. In heavy machinery and plant such as excavators or vehicles operating in harsh environments such as mines, the coating not only protects against condensation corrosion and exhausts but will also protect against abrasion of where fine dusts or sand is present. Offshore, SÄKAPHEN Si 57 EL in conjunction with a polyurethane top coat has shown superior performance on herringbone style Air Coolers installed in Wind Turbines in the coastal regions of Asia.