Stage-controlled heating system with self recuperative burner
Self recuperative burners feature an integrated heat exchanger (recuperator) to preheat the combustion air. Flue gas and combustion air are fed through a heat exchanger in the opposite direction. Depending on the burner model and mode of operation, 30 % energy savings can be achieved with air preheating up to 700 °C in comparison to cold air burners. Self recuperative burners are used for direct heating in conjunction with an eductor for extracting the flue gases from the furnace chamber. The eductor generates a vacuum with a centrally positioned nozzle and thus draws approx. 90 % of the flue gases out of the furnace chamber along the outside of the burner’s heat exchanger. The remaining quantity of flue gas air is discharged from the furnace via an additional flue gas opening and in this process is also used for furnace pressure control.
Self recuperative burners are controlled by a rotary impulse system in staged ON/OFF control mode. A variable gas/air ratio control is used to control the gas/air ratio. Alternatively, the air flow can be monitored by a pressure switch.