Utilizing Waste Heat in Flue Gas



AB&CO · TT BOILERS are a well-known Danish boiler manufacturer, who have specialised in small and medium size customised heaters and boilers.




AB&CO · CONSULT design and optimise customised heat recovery i.e. exhaust gas boilers, economisers, heat exchangers etc.

AA heat recovery solution start on consultant basis by AB&CO · CONSULT and can be effectuated in manufacturing the equipment by AB&CO · TT BOILERS. This ensures the best solution for customer.


   Assistance in Optimizing Heat Recovery
Introduction to Economisers and Exhaust Gas Heaters & Boilers
Download :  Booklet about Heat Recovery  
Download :  AB&CO · CONSULT - Your Heat Recovery Partner  
Download :  AB&CO · TT BOILERS - 'The Boiler Maker'  


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Flue gas / exhaust gas contains a large amount of heat.  It comes from engines and these often produced flue gas at very high temperatures - or it comes from fired heaters where the flue gas temperatures is somewhat lower, but often the amount of exhaust gas is much larger.

Instead of wasting the heat, the boilers and heaters for heat recovery offer very good opportunities for utilizing the waste heat for production of steam, hot thermal oil or hot water.



Today process heat recovery offers substantial economical advantages - due to reduction of CO2 and saving the fuel. Furthermore heat recovery gives a good environmental profile, that is required by many authorities and business contacts.

The engineers of AB&CO · CONSULT and AB&CO · TT BOILERS have many years experience ensuring optimum solution for customers. 

Heat recovery of process heat can be utilized in many type of heat exchangers - not limited to boilers as this chapter describe.

Boilers and heaters for heat recovery, are also called economizers.


Basically these are heat exchangers. The output depend on the size and design of the unit, but most of all it depends of the flue gas temperature, flue gas amount and the thermal properties on the other side. This means that the very hot flue gas from engines permits production of high pressure steam steam and high temperature thermal oil, while the colder flue gas from heaters and boilers only permits heating of water at moderate temperatures.

Like heat exchangers in general, the same output the economizer can result in small and short, long and narrow, or big and width units. The design change from case to case.

Below is an example of a heating system with an economizer operating as a steam boiler - a special economizer steam boiler system.

Economizers installed on TT BOILERS thermal oil heaters
Supply of skidmounted hot oil systems for China, Thailand and Malaysia


TT BOILERS Flue Gas Steam Boiler with by-pass
Left :  Ready for Delivery         Right : Illustration



Boilers and heat exchangers for heat recovery is very often  a part of a total system.
An example of a recuperative steam boilers system is shown below

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