Pyrrole, the smallest molecule with a nitrogen atom in the heterocycle ring, is an important tar component from coal and nitrogen-rich biomass devolatilization. Understanding the combustion chemistry of pyrrole can help to elucidate the pollutant formation chemistry from fuel nitrogen, thus enabling cleaner biomass energy utilization technologies. Experimental measurements were performed in a jet stirred reactor coupled with time of flight molecular beam mass spectrometry using synchrotron vacuum ultraviolet beam as photon ionization source, and gas chromatography-mass spectrometry to provide comprehensive measurements of 31 species including nine C4 and C5 N-containing compounds. Based on the evidence from the experiments and aiming to improve the kinetic model performance, possible formation routes are proposed with OH addition as the entrance reaction. Reaction rate coefficients for the OH addition channel as well as those for key H-atom abstraction reactions (H, OH, CH3, and HO2) were calculated by quantum chemical methods and updated in the model. The updated model can qualitatively predict the identified C4 N-containing species and perform reasonably well for a large set of experimental data considered for validation, overall improving the performance of the previous model. The influence of the investigated reactions on the predictions of fuel reactivity and pollutant formation motivates further investigations of N-containing fuel chemistry.
Bibliographical noteFunding Information:
BC, CH, KL, and HP acknowledge the financial support by the Deutsche Forschungsgemeinschaft under Germany´s Excellence Strategy – Cluster of Excellence 2186 „The Fuel Science Center” – ID: 390919832. SF and HP acknowledge the support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the framework of the collaborative research center SFB/Transregio 129 “Oxyflame”. The IE calculation work was supported by the funding from KAUST CRG project under project number URF/1/4688–01–01. The experimental work was supported by Hefei Science Center, CAS(2020HSC-KPRD001 and 2021HSC-UE005). The kinetic model work at Politecnico di Milano was funded by the European Union's Horizon 2020 Research and Innovation Program (Grant Agreement 723706 - IMPROOF Project, H2020-IND-CE-2016–17/H2020-SPIRE-S016).
- Fuel nitrogen
- H-atom abstraction
- N-containing species
- OH addition
ASJC Scopus subject areas
- Chemical Engineering(all)
- Mechanical Engineering
- Physical and Theoretical Chemistry