The economizer performs a key function in providing high overall boiler thermal efficiency by recovering low-level energy from flue gas before it's exhausted to the atmosphere. This energy recovery occurs by heating the boiler feedwater.

Economizers are tubular heat transfer surfaces that preheat boiler feed water before it enters the steam drum or furnace surfaces. They reduce operating costs by recovering extra energy from flue gas, resulting in significant fuel savings.

Economizers also reduce the potential for thermal shock and strong water temperature fluctuations as feed water enters the drum or waterwalls. Increasingly stringent environmental regulations limiting nitrogen oxides and sulfur dioxide emissions can affect economizer design.

The gas-side heat transfer coefficient is much less than the water-side coefficient. To compensate, the outer surface of tubes may be finned to increase heat transfer surface area. The ultimate goal of economizer design is to achieve necessary heat transfer at minimum cost, with maximum allowable flue gas velocity being a key design criterion.

Material: Carbon Steel, Alloy, Austenitic Steel (Nickel and Chromium or Manganese)

• Impact test and Strength calculation report with applied materials information
• 100% NDT (non-destructive inspection) report of steel plate, tube and electrode
• X-ray, γ-ray and liquid penetrant test inspection report (welding seam) to ensure the quality of the entire boiler
• Hydraulic test report to ensure standard working pressure and safety