Combustion Method to Reduce NOx and Save Fuel for Burners for Forge Furnace

To save fuel in a forge furnace, it is effective to recover heat by pre-heating combustion air. This requires a choice out of recuperators, recuperative burners and regenerative burners in proportion to the size or type of the furnace. Then we have worked out the methods to reduce NOx for each system realistically with due regard to the cost and put them into practice. For the regenerative burner, assuming that most of the NOx is formed at the flame retaining area, we designed a very simple one whose combustion ratio of the flame retaining area is very small so that the retention flame is made up of very little ambient temperature auxiliary air. The simplicity of the burner has reduced not only NOx but also the cost of the overall regenerative system. In a forge furnace with the developed regenerative burner, we achieved NOx emission less than 200 ppm (O2=0%,1300°C furnace temperature) and a fuel saving rate of about 50%.