A kinetic study of NO formation during oxy-fuel combustion of pyridine

• Published in: Applied energy 2012-04, Vol.92, p.361-368
• Main Authors: Wang, B., Sun, L.S., Su, S., Xiang, J., Hu, S., Fei, H.
• Format: Article
• Language: English
• Subjects: Applied sciences; atmosphere; Atmospheres; Carbon dioxide; Combustion; Conversion; Energy; Evolution; Exact sciences and technology; fuels; Kinetic modeling; Mathematical models; Nitric oxide; nitrogen; Oxy-fuel; oxygen; Pyridine; Pyridines; Reaction kinetics; temperature
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2011.11.039

► Pyrolysis and combustion studies of pyridine are conducted on a flow reactor. ► We employ model compound to simulate fuel-nitrogen conversion in O 2/CO 2 atmosphere. ► Pyrolysis products serve as the input parameters of combustion simulation. ► High concentration of CO 2 promotes reaction of HNO + M ↔ H + NO + M to suppress NO formation. In this work, pyridine-N was converted into NO and N 2 by using a flow reactor and the dominant NO evolution pathways were identified by means of a kinetic modeling under O 2/CO 2 atmosphere in temperature range of 1073–1473 K for different stoichiometries. The experimental results indicated higher temperatures promoted the formation of NO, with conversions varied from 1.26–18.64% to 3.85–43% for fuel-rich and fuel-lean conditions respectively. As for N 2 formation, conversion of pyridine to N 2 had a slight increase from 1073 to 1173 K then declined rapidly in oxidizing atmosphere, whereas this conversion stabilized at about 36% before decreasing to 29% above 1173 K in the presence of insufficient O 2. Increasing the equivalence ratio led to a monotonic increase of NO in both O 2/Ar and O 2/CO 2 atmospheres, and the gap between these atmospheres developed with α. The simulation results showed that the high CO 2 concentration reduced the availability of oxygen thus altered the evolution of NO through promoting reaction HNO + M ↔ H + NO + M and limiting reaction HNO + O 2 ↔ HO 2 + NO. This was even more important at higher temperatures. Besides, the major pathways for NO consumption were taken through reaction with NCO and NH as intermediates. In general, the model of Terasa09 described the experimental trends well, and this combustion kinetic was applicable to oxy-fuel conditions.