산업용 보일러의 무탄소 연료 전환에 따른 열 성능 평가

Abstract

The conversion of industrial boilers to carbon-free fuels is one of the strategies for reducing carbon emissions. Hydrogen and ammonia, as representative carbon-free fuels, emit no CO2 during combustion, and when co-fired with LNG in existing boilers, affect flame temperature, flue gas composition, and flow rate, thereby influencing overall heat transfer characteristics. To evaluate these effects, a process simulation-based model dividing the boiler into radiation and convection zones was developed. The variations in radiative and convective heat transfer characteristics according to variation in the co-firing ratio were quantitatively analyzed, and boiler efficiency was assessed. Variations in flame temperature and flue gas composition affected furnace emissivity and radiative heat transfer, which in turn influenced flue gas temperature, flow rate, and convective heat transfer. As a result of the simulation, hydrogen co-firing increased radiative heat transfer and decreased convective heat transfer, leading to improved boiler efficiency. In contrast, ammonia co-firing decreased radiative heat transfer and increased convective heat transfer, resulting in degraded boiler efficiency. These findings are expected to serve as a basis for the design and operational optimization of industrial boilers utilizing carbon-free fuels.