Combustion and emission characteristics of gas-coal dual-fuel boilers
WANG Yongying
Abstract：This study investigates the combustion characteristics and pollutant emissions of a 70 MW natural gas/pul-verized coal dual-fuel hot water boiler system in Jinan,Shandong.Experimental research was conducted on three fu-els:Shenfu bituminous coal,blue-coke,and natural gas,focusing on flame morphology,furnace temperature dis-tribution,and nitrogen oxide(NOx)emissions under 50-70 MW loads.Results indicate that fuel properties signifi-cantly affect combustion behavior.Blue-coke with low volatile content(8.29%)and high fixed carbon(76.35%)concentrates high-temperature zones in the upper-middle furnace(maximum ΔT=321℃),while Shenfu coal exhib-its uniform temperature distribution(ΔT=70℃)due to its higher volatiles(31.29%).Natural gas combustion forms mid-furnace high-temperature regions.NOx emissions correlate strongly with fuel-bound nitrogen,with raw e-missions of 580 mg/m3(Shenfu coal),325 mg/m3(blue-coke),and 113 mg/m3(natural gas)at reference O2 levels of 9%and 3.5%respectively.Air-staging technology reduced NOx by 40%,31%,and 27%for the three fu-els,while 22%flue gas recirculation further lowered natural gas NOx to 28 mg/m3.This study demonstrates the dual-fuel system's advantages in fuel flexibility and low-emission performance,providing theoretical and technical in-sights for industrial boiler decarbonization.
Keywords：dual-fuel boilercombustion characteristicsNOx emissionsair-staged combustionflue gas recircu-lation
Publication Date：2026-01-31
Pages：6( 60-65 )