Theoretical study of the effect of hydrogen radicals on the formation of HCN from pyrrole pyrolysis

Ji Liu, Xiaolei Zhang, Alexander Shaw, Qiang Lu, Bin Hu, Chang-qing Dong, Yong-ping Yang

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

As a typical fossil fuel, coal is a major contributor to nitrogen oxide (NOx) pollution. The detailed mechanism of NOx generation from coal pyrolysis need to be clarified. Within this research, we used density functional theory (DFT) to investigate the formation mechanism of HCN as a NOx precursor during pyrolysis of pyrrole in the presence of hydrogen (H) radicals. Firstly, three different reaction positions for hydrogen radical attacking were compared. It was identified that hydrogen radical initially reacts with pyrrole at the location adjacent to N through a single elementary reaction step with an activation energy of 77.12 kJ/mol. Additionally, to examine the role of hydrogen radical in the pyrrole pyrolysis to form HCN, 12 subsequent reaction pathways were theoretically investigated. It was found that one of the pathway (Pathway a-4) involving hydrogen transfer followed by carbon-carbon cleavage processes is the route with the lowest energy barrier of all of the mechanisms reported, thus it plays an important role in the formation of HCN from the pyrrolic components of coal. These results further indicated that the hydrogen radicals significantly reduce the energy barrier of the pyrrole pyrolysis.
LanguageEnglish
JournalJournal of the Energy Institute
Early online date4 Sep 2018
DOIs
Publication statusE-pub ahead of print - 4 Sep 2018

Fingerprint

pyrroles
pyrolysis
Pyrolysis
Hydrogen
nitrogen oxides
hydrogen
coal
Nitrogen oxides
Energy barriers
Coal
fossil fuels
carbon
Carbon
pollution
cleavage
Fossil fuels
Density functional theory
routes
Pollution
activation energy

Keywords

  • NOx
  • hydrogen radicals
  • HCN
  • pyrrole
  • DFT

Cite this

Liu, Ji ; Zhang, Xiaolei ; Shaw, Alexander ; Lu, Qiang ; Hu, Bin ; Dong, Chang-qing ; Yang, Yong-ping. / Theoretical study of the effect of hydrogen radicals on the formation of HCN from pyrrole pyrolysis. In: Journal of the Energy Institute. 2018.
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abstract = "As a typical fossil fuel, coal is a major contributor to nitrogen oxide (NOx) pollution. The detailed mechanism of NOx generation from coal pyrolysis need to be clarified. Within this research, we used density functional theory (DFT) to investigate the formation mechanism of HCN as a NOx precursor during pyrolysis of pyrrole in the presence of hydrogen (H) radicals. Firstly, three different reaction positions for hydrogen radical attacking were compared. It was identified that hydrogen radical initially reacts with pyrrole at the location adjacent to N through a single elementary reaction step with an activation energy of 77.12 kJ/mol. Additionally, to examine the role of hydrogen radical in the pyrrole pyrolysis to form HCN, 12 subsequent reaction pathways were theoretically investigated. It was found that one of the pathway (Pathway a-4) involving hydrogen transfer followed by carbon-carbon cleavage processes is the route with the lowest energy barrier of all of the mechanisms reported, thus it plays an important role in the formation of HCN from the pyrrolic components of coal. These results further indicated that the hydrogen radicals significantly reduce the energy barrier of the pyrrole pyrolysis.",
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Theoretical study of the effect of hydrogen radicals on the formation of HCN from pyrrole pyrolysis. / Liu, Ji; Zhang, Xiaolei; Shaw, Alexander; Lu, Qiang; Hu, Bin; Dong, Chang-qing; Yang, Yong-ping.

In: Journal of the Energy Institute, 04.09.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Theoretical study of the effect of hydrogen radicals on the formation of HCN from pyrrole pyrolysis

AU - Liu, Ji

AU - Zhang, Xiaolei

AU - Shaw, Alexander

AU - Lu, Qiang

AU - Hu, Bin

AU - Dong, Chang-qing

AU - Yang, Yong-ping

PY - 2018/9/4

Y1 - 2018/9/4

N2 - As a typical fossil fuel, coal is a major contributor to nitrogen oxide (NOx) pollution. The detailed mechanism of NOx generation from coal pyrolysis need to be clarified. Within this research, we used density functional theory (DFT) to investigate the formation mechanism of HCN as a NOx precursor during pyrolysis of pyrrole in the presence of hydrogen (H) radicals. Firstly, three different reaction positions for hydrogen radical attacking were compared. It was identified that hydrogen radical initially reacts with pyrrole at the location adjacent to N through a single elementary reaction step with an activation energy of 77.12 kJ/mol. Additionally, to examine the role of hydrogen radical in the pyrrole pyrolysis to form HCN, 12 subsequent reaction pathways were theoretically investigated. It was found that one of the pathway (Pathway a-4) involving hydrogen transfer followed by carbon-carbon cleavage processes is the route with the lowest energy barrier of all of the mechanisms reported, thus it plays an important role in the formation of HCN from the pyrrolic components of coal. These results further indicated that the hydrogen radicals significantly reduce the energy barrier of the pyrrole pyrolysis.

AB - As a typical fossil fuel, coal is a major contributor to nitrogen oxide (NOx) pollution. The detailed mechanism of NOx generation from coal pyrolysis need to be clarified. Within this research, we used density functional theory (DFT) to investigate the formation mechanism of HCN as a NOx precursor during pyrolysis of pyrrole in the presence of hydrogen (H) radicals. Firstly, three different reaction positions for hydrogen radical attacking were compared. It was identified that hydrogen radical initially reacts with pyrrole at the location adjacent to N through a single elementary reaction step with an activation energy of 77.12 kJ/mol. Additionally, to examine the role of hydrogen radical in the pyrrole pyrolysis to form HCN, 12 subsequent reaction pathways were theoretically investigated. It was found that one of the pathway (Pathway a-4) involving hydrogen transfer followed by carbon-carbon cleavage processes is the route with the lowest energy barrier of all of the mechanisms reported, thus it plays an important role in the formation of HCN from the pyrrolic components of coal. These results further indicated that the hydrogen radicals significantly reduce the energy barrier of the pyrrole pyrolysis.

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