Heat recovery at high flue gas temperatures

Where are economisers applied?

This type of heat exchanger has many possible applications.

The operating principle of an economiser

Tubes are installed in the flue gas stream. Water flows through those tubes absorbing heat from the hot flue gas. The recovered heat can be used to preheat boiler feedwater, process water or a water glycol system. Heat recovery through an economiser delivers significant savings in CO₂ emissions and energy costs. 

The recovered heat can be used in many ways

• Preheating of boiler feed or process water.
• Heating thermal oil or water glycol.
• To heat buildings.
• For cleaning processes.
• For transport to and use at another location.

Economiser models

Economisers can be made in different configurations.

ONTWERPKEUZE

What design is the best match for you?

Your specific application requires a tailored design. Is/are your flue gas, baking fumes or drying air clean and dust-free, or is it corrosive and does it contain sulphur or other contaminants? If the wrong design choice is made, maintenance and operational costs will rise, while efficiency falls. Below is an overview of different types of flue gas, baking fumes or drying air and points of interest when it comes to the design.

Your flue gas or drying air is clean

If the air is free of contaminants and dust, carbon steel and finned tubes are suitable. As the fins increase the heat exchange surface area, this makes for an economical and compact design.

Your flue gas is corrosive

When corrosion is lurking, bare tubes without external fins are a better option. In addition, the structural material must be able to cope with corrosive process conditions. Polymers resistant to extreme corrosion are perfectly suited for this purpose.

Your flue gas, baking fumes or drying air is contaminated

In case of heavily contaminated flue gases, bare tubes combined with an inline cleaning system are the best option. Clogging can occur between finned tubes. The lack of an inline cleaning system can lead to dirt accumulation, which will greatly reduce the efficiency of the heat exchanger, resulting in efficiency reductions.

Your flue gases have a high temperature

At high temperatures, it is recommended to weld the tubes not on two, but only onOne side. This allows the tubes to move freely through the flue gas, therebyreducing thermal tensions. Heat Matrix is happy to help you make the right choices.