Energy, fuels, and chemicals 



3187 



burner has also been proposed. Such a system will fit into future mill energy 

 needs by providing a higher ratio of electric power to steam power while 

 utilizing a variety of low-grade fuels (Moody 1976). 



In the fluidized-bed burner shown (fig. 26-19), the bed is preheated to 700 or 

 750°F with a non-fluidized airflow for startup. Then, a small amount of fuel 

 spontaneously ignites as it is added to the bed. Once a flame is established, the 

 bed is fluidized by increasing the airflow and then fuel feed is started. As 

 combustion becomes self-sustaining, the temperature of the bed will rapidly rise 

 into the operating range of 1 ,000 to 1 ,800°F. Preheat burners can then be turned 

 off and no auxiliary fuel is required. 



HOT GAS DUCT 

 TO KILN, VENEER 

 DRYER. BOILER 



FUEL IN 



OVERFIRE AIR 

 VORTEX SYSTEM 



FLUIDIZED BED 



INSULATION 

 BLOCK 



REFRACTORY 



BED MATERIAL 



SCREENING 



UNIT 



BED MATERIAL 

 RE- INJECTION 

 BLOWER 



COMBUSTION 

 AIR BLOWER 



Figure 26-19. — Fluidized bed combustion unit. (Drawing from Energy Products of 

 Idaho.) 



