Customized Advanced Economizer For Power Station Pulverized Coal Fired Boilers

Customized Advanced Economizer For Power Station Pulverized Coal-Fired Boilers

What are staged economizer arrangements?

 High-temp stage (anti-corrosion) & low-temp stage (high recovery), ΔT control is critical.

Summary
 
There are three stages from the feed water in the boiler heated into superheated steam:feed water preheating, evaporation, and superheating. The three stages are finished on three different heating surfaces. The boiler steam and water circuit are composed of the three different heating surfaces as well as their connecting pipes. Boiler economizers are one of them, and it is right the equipment to preheat the feed water. Thus, it is the heating surface with the lowest temperature for boiler working fluid in the boiler steam and water circuit. The working fluid passing through this equipment is monophasic water(non-boiling economizer).

 
Types

Economizers are classified by material into steel tube (common in medium/large boilers for strength, heat transfer, and cost-effectiveness, with modern water treatment solving corrosion issues) and iron types. By function, they’re non-boiling (outlet temp 20–25°C below pressure-based boiling point) or boiling (vaporizing 10–15% of feed water, used in medium-pressure boilers to prevent combustion instability, reduce superheater metal use, and optimize heat recovery without exceeding 20% vaporization to avoid flow resistance).

Superhigh pressure boilers mostly use non-boiling economizers. Higher pressure reduces latent heat of vaporization while increasing water heating needs, so more heat goes to water wall panels to avoid furnace/flue gas overheating and slagging.
Boiler parameters drive economizer type choice. Different parameters alter heat absorption ratios across heating stages, requiring adjusted surface arrangements. In high-parameter units, lower evaporative heat absorption and higher water/steam heating needs make non-boiling economizers dominant.
 
Functions
1. fuel saving: the economizers are placed at the rear part of boilers. This way can decrease the smoke and gas temperatures, thus to save fuels.
2.improve the working conditions of steam drums: due to economizers, the feed water temperature is increased when entering the steam drum. It reduces the temperature difference between the feed water and steam drum wall as well as steam drum thermal stress, so that it improve the working conditions of steam drums and increase the service life.
3.reduce the boiler manufacturing cost: for the feed water is heated in the boiler economizers. The use of low temperature spare parts as boiler economizers to replace some of high-priced high temperature water wall panels reduces the cost to manufacture boilers.
 
 
 
Specifications

 
Quality Control
 
1. Impact test and Strength calculation report with applied materials information.
2. 100%NDT(non-destructive inspection) report of steel plate, tube and electrode
3. X-ray, γ-ray and liquid penetrant test inspection report (welding seam): to ensure the quality of the entire boiler
4. Hydraulic test report: ensure the standard working pressure and safety