A.) Types of Economizer on the basis of construction :
1. CI Gilled Tube Economizer :
The gilled tube economizers are made up of cast iron which are fabricated using graded cast iron fins, have following features,
1. High optimum efficiency due to proper contact of gills with tubes.
2. Commonly used in plants where intoxicated flue gas is generated due to the quality of fuel burnt.
2. Round Gilled Tube Economizer :
This is made by mild steel fabricated with square and round fins, welded on carbon steel seamless tubes, have the feature,
1. Proper contact between the tubes and fins are ensured for optimum efficiency.
3. Coiled Tube Type Economizer:
These are used mostly in thermal power plants and large processing units. These coiled tube type Economizers are fabricated out of carbon steel seamless, have following features,
1. These are very efficient in recovering the heat from gases.
2. Occupy very little space.
4. Horizontal Finned Tube Economizer :
In this is carbon steel seamless tube sealed – welded with horizontal fins to make a complete assembly of economizer for heat transfer, have following features,
1. Proper care is taken for making the contact of fins with tubes for perfect heat transfer.
2. These are used mainly used by Thermal Power Plants.
B.) Types of Economizers Based on Boiler Efficiency:
1. Non – condensing Economizer 2. Condensing Economizer