| OCR Text |
Show 5 Boundary Layer Staging A review of current techniques generated many ideas. For instance, the patented, International Flame Research Foundation (IFRF) burner employs internal flue-gas recirculation (inert gas NOx control). In this burner, injecting gas toward the burner centerline from a point outside the burner throat, entrains inert furnace gases with the fuel before mixing with the combustion air. Excellent low NOx performance results. Therefore, the question arose, could internal flue-gas recirculation work in a conventional burner? RIM Corporation, also, very successfully employs fuel richlfuellean techniques to meet NOx compliance in oil- and coal-fired units. Would such techniques economically work in gas-fired burners? Extensive studies using three-dimensional, fully reacting, NDx-predicting CFD models explored the feasibility of several promising concepts. A careful review of the results of these efforts proved that injecting natural gas fuel closer to the burner throat caused NOx to decline. Carrying this trend toward its natural conclusion resulted in anew, low NOx concept for conventional gas burners. RIM Corporation named this new concept Boundary Layer Staging. Boundary layer staging patents are pending. See Figure 3. BOUNDARY LAYER STAGING Figure 3 |
