8. Thermal post-treatment processes

8.1 Afterburning of flue gases

Gases from a primary heat treatment chamber are generally still laden with combustible unburnt gases, due to the various limiting factors encountered in practice in primary furnaces (mixing defects, short circuits, cold spots, recalcitrant species...). It is therefore always necessary to carry out post-combustion treatment of the primary flue gases before directing them to the devices for energy recovery and abatement of particulate and gaseous pollutants.

This type of after-treatment consists of re-burning the excess air gases, so as to completely oxidize the residual unburnt gases. The chamber used is known as the afterburner chamber.

Assuming a piston-type flow of fumes in this enclosure, with a concentration...