Emissions and energy/exergy efficiency in an industrial boiler with biodiesel and other fuels

Abstract

Industrial boilers are significant equipment in industrial operations used to provide steam or heat for production. More than 80% of fire-tube boilers use heavy oil in small and middle industries in Taiwan. Due to biodiesel as a sustainable fuel, the objective of this study is to measure experimentally and evaluated energy and exergy analysis of the fire-tube boiler using biodiesel (BD), undistilled biodiesel (UB), low sulfur oil (LSO), and ultra-low sulfur diesel (ULSD), and the various mixing ratios of undistilled biodiesel and low sulfur oil (UB90, UB70, and UB50) to reduce emissions from fire-tube boilers. Results from BD and UB are comparable, and UB exhibited a high NOx reduction rate of 68.9% and a high SO2 reduction rate of 99.5% compared to LSO. The boiler that employed UB decreased CO2 emissions, NOx, and SO2 emissions. NOx emission increases with increasing LSO content. The boiler’s maximum energy efficiency when using BD is 86.6%, and the overall exergy efficiency is 44.8%. The boiler with UB70 had the lowest energy efficiency of 73.5% and the lowest exergy efficiency of 38.7% because of the increased heat loss. The Benefits of this study are not only for boiler applications but also for government policy references.