What are the common types of boiler economizers?

As far as I know, there is only one type of economizer; it’s just arranged differently, with some arranged horizontally and others vertically

Based on material, they can be divided into cast iron type and steel pipe type； Based on structure, they can be divided into fin-type and membrane-type.

A economizer is a heat exchanger located in the flue at the rear of the boiler, which uses the residual heat from the exhaust gases to raise the temperature of the feed water. Its function is to raise the feedwater temperature, reduce heat losses through exhaust gases, improve the thermal efficiency of the boiler, and save fuel consumption. The economizers of medium and low-pressure boilers (boilers with a working pressure of 2.5 MPa or less) are generally made of cast iron, while those of boilers with pressures above medium level consist of serpentine tubes made of steel. The cast iron economizer consists of a series of horizontal cast iron pipes, with the ends of the pipes connected by cast iron elbows. Fins are cast on the outside of the tube to increase the heating surface on the flue gas side. Steel tube economizers are typically composed of serpentine tubes made by bending seamless steel tubes with an outer diameter of 32–38 mm. The transverse pitch S1 of the tubes is limited by the ash accumulation on the heating surface and the conditions under which the tubes are supported; generally, S1 = 2–3d. The longitudinal pitch of the tubes depends on their bending radius, with the bending radius R of the economizer tubes usually being about twice the outer diameter of the tubes.

It can be divided into steel pipe type and cast iron type. Among them, the steel tube type is not limited by pressure and can be used in boiling type, while the cast iron type is limited by pressure.

There are mainly two categories of economizers used in boilers: cast-iron finned tube economizers and steel tube economizers. The former is mainly used in industrial boilers with small capacity, or primarily in boilers with large capacity. There is also a type called a heat pipe economizer, which makes use of heat pipe technology

Based on their material, economizers can be divided into two types: cast iron type and steel tube type. (1) Advantages of the cast-iron economizer: Due to its thick walls, high hardness, and a layer of cast skin on its surface, the cast-iron economizer is resistant to wear and corrosion, thus having a long service life. Disadvantages: Complex processing, high cost, heavy maintenance requirements, not resistant to water hammer, and cannot be used as a boiling economizer. Therefore, it is often used in small boilers that lack deaerators or have inadequate deaeration. (2) Advantages of steel-tube economizers: simple manufacturing process, low cost, easy installation, minimal maintenance requirements, and the ability to withstand water hammer; therefore, boiling economizers must be made of steel tubes. It is widely used in large and medium-sized boilers. Disadvantages: It has poor wear and corrosion resistance, and its service life is shorter than that of cast-iron types; it is mainly used in large and medium-sized boilers with improved deoxygenation.

Series of Technical Q&A Books for Power Plant Workers: Q&A on Boiler Operation and Maintenance Techniques – Book Materials 129 4.1.43 What is the function of a economizer? 129 4.1.44 How many types of economizers are there based on their material composition? What are the advantages and disadvantages of each type? 130 4.1.45 In an economizer... 206 5.1.47 What are the common types of coal feeding equipment used in fluidized bed boilers? 206 5.1.48 Into which two categories can the coal feeding methods in circulating fluidized bed boilers be divided according to the location where the coal is fed? 207...

Cast-iron economizer, and steel-tube economizer

The tube bundle of our economizer is finned and arranged horizontally; the material used should be seamless steel tubes, specifically carbon steel! !

Based on the material, they are divided into cast-iron type and steel-tube type; based on heat transfer mechanism, they are classified as boiling-type and non-boiling-type. Cast iron is used in small boilers, while steel-tube type is employed in medium and large boilers. Large boilers generally use non-boiling-type economizers, whereas small and medium-sized boilers mostly use boiling-type economizers.