Autorecuperative burners use the same principle of heat exchangers, as they recycle the heat of exhaust gases to preheat the combustion air before it gets mixed with the fuel. Different from external systems however, the heat exchanger is incorporated inside the burner and can be built in various metallic or ceramic materials (SiC).
Self recuperative burners uses various technical devices (grooves, fins, flow countercurrent etc…), meant to increase the contact surface between the flue gases and the incombustion air coming in from the supply pipe.
Self recuperative burners are high velocity burners, free flame, long or flat flame, but they also are available in indirect fire version for radiant tubes.
There are many advantages in using a burner that integrates a recuperator.
- Higher efficiency is allowed in the combustion process (especially when the working temperature increases) that can reach up to 80% compared with the efficiency of a traditional cold air burners.
- Compared with an external heat exchanger, the use of an autorecuperative burner is much more practical, flexible and economical:
- Economical, since engineering and installation expenses are reduced as an external heat exchanger must be designed specifically, whilst the autorecuperative burners constitute a preassembled “package” with the necessary instruments and is very easy to assemble and replace.
- Practical, as they are much easier to replace in revamping already existing furnaces thanks to universal adapting flanges.
- Flexible, as if there is a problem, in an external exchanger the entire furnace must be stopped whereas with an integrated exchanger, just the single burner can be changed.