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Show ULTRA-LOW-EMISSION BURNER FOR BOILERS AND FLUID HEATERS by: Hamid A. Abbasi, Mark J. Khinkis, and David F. Cygan Institute of Gas Technology Chicago, IL 60616 ABSTRACT The Institute of Gas Technology (IGT) is developing a premixed cyclonic combustion aptroach for boilers and indirect fluid heaters in the range of 5 to 300X 10 Btufh. When fired with natural gas, this advanced design approach is expected to provide NOx emissions below 15 vppm while maintaining CO levels below 50 vppm and total hydrocarbon (THC) levels below 10 vppm (all at 0% 02). With oil (backup), the NOx as well as CO and THC emissions would still be very low - all below 50 vppm at 0% 02. The ultra-low NOx emissions are achieved by exploiting two unique characteristics of cyclonic combustion internal recirculation of partially cooled combustion products and high convective heat transfer. These characteristics are enhanced in the IGT premixed design not only to decrease the overall combustion temperatures, but also to create very uniform temperature and oxygen profiles, thereby significantly decreasing the peak flame temperatures as well as the localized pockets of high 02 availability - the primary causes of NOx formation. This paper discusses the concept and the resul ts of the proof -of - concept tes ts carried out on 1 . 6 and 8 X 106 Btufh (40 and 200 hp) flexible test burners at IGT's Energy Deve lopment Center. The resul ts show s table operation and the potential for about 15 ppm NOx with less than 50 ppm CO «2 ppm THC) with combustion air staging, and less than 10 ppm NOx with less than 30 ppm CO «1 ppm THC) by simply using 45% excess air. The very low emissions with high excess air show the potential for similar reductions by the use of flue gas recirculation (FGR). The initial development effort is being targeted at the firetube boiler retrofit market and will focus on the optimization of combustion air staging. |
