Radiative characteristics of premixed Coke Oven Gas-Ammonia swirling flames

• Radiation emission and absorption characteristics of coke oven gas (COG) − ammonia flames are investigated. • Internal radiation theoretical analysis method is verified using infrared spectrometry data. • The radiation characteristics of H 2 O and CO 2 in the combustor are discussed respectively. Coke Oven Gas (COG) is a by-product gas generated during coal carbonisation in coke ovens, containing H 2 , CH 4 , CO, CO 2 , and N 2 . Since COG is currently used as a heat source in steel works, co-firing COG with green ammonia is considered a promising decarbonisation method for steel works. However, experimental studies investigating the radiation characteristics of ammonia blended flames are limited, not only for COG-NH 3 blends. In this study, combustion experiments with premixed COG-NH 3 swirling flames are conducted at various COG-NH 3 blends (0 ≤ X NH3 ≤ 0.9) and equivalence ratios (0.6 ≤ Φ ≤ 1.4), and their radiation characteristics are investigated. Specifically, an infrared spectrometer is used to investigate the typical wavelengths (2220, 2600 and 2700 nm) of NH 3 , H 2 O, and CO 2 in the post flame zone, and a theoretical analysis of the internal radiation of the combustor is conducted based on the exhaust gas temperature and concentrations measurements. The results revealed that radiation primarily from H 2 O and CO 2 peak at stoichiometric conditions, and interestingly, the change in radiation is more gradual on the rich side than on the lean side. It is also found that as the NH 3 fraction in the fuel increase, H 2 O derived radiation increase while CO 2 derived radiation decrease. Furthermore, the results suggest that while H 2 O radiation is dominant over CO 2 , differences in radiation due to blending are primarily caused by CO 2 . The findings from this study significantly contribute to the development of ammonia blended combustion systems that take radiation characteristics into account.