A theoretical investigation on the thermal decomposition of pyridine and the effect of H₂O on the formation of NO_x precursors

Abstract

Pyridine is one of the main nitrogen-containing compounds in coal, and its pyrolytic mechanism to generate NO_x precursors (mainly NH₃ and HCN) remains unclear. In this work, the possible pathways for the pyrolysis of pyridine to form HCN and/or NH₃ were investigated by the density functional theory method, and the effects of H₂O on pyridine pyrolysis were also investigated. The results show that there are two possible reactions for the initial pyridine pyrolysis, i.e., internal hydrogen transfer and C–H bond homolysis, and that internal hydrogen transfer is more favorable. Nine possible reaction pathways following internal hydrogen transfer are obtained and analyzed. Among these pathways, pyridine prefers to produce HCN instead of NH₃. The existence of H₂O has significant effects on the decomposition of pyridine, as it participates in pyridine pyrolysis to form NH₃ rather than HCN as the major product.

Graphical abstract

Keywords

coal / pyridine / pyrolysis mechanism / NO_x precursors / DFT

References

[1] Ye C, Zheng Y, Xu Y, Li G, Dong C, Tang Y, Wang Q. Energy and exergy analysis of poly-generation system of hydrogen and electricity via coal partial gasification. Computers & Chemical Engineering, 2020, 141: 106911

[2] Xu M X, Wang H X, Ouyang H D, Zhao L, Lu Q. Direct catalytic decomposition of N₂O over bismuth modified NiO catalysts. Journal of Hazardous Materials, 2020, 401: 123334

[3] Satayeva A R, Howell C A, Korobeinyk A V, Jandosov J, Inglezakis V J, Mansurov Z A, Mikhalovsky S V. Investigation of rice husk derived activated carbon for removal of nitrate contamination from water. Science of the Total Environment, 2018, 630: 1237–1245

[4] Cheng S, Qiao Y, Huang J, Wang W, Wang Z, Yu Y, Xu M. Effects of Ca and Na acetates on nitrogen transformation during sewage sludge pyrolysis. Proceedings of the Combustion Institute, 2019, 37(3): 2715–2722

[5] Kyriienko P I. Selective catalytic reduction of NO_x with ethanol and other C1–4 oxygenates over Ag/Al₂O₃ catalysts: a review. Frontiers of Chemical Science and Engineering, 2020, 14(4): 471–491

[6] Chu F, Su M, Yang G. Heat and mass transfer characteristics of ammonia regeneration in packed column. Applied Thermal Engineering, 2020, 176: 115405

[7] Fan W, Li Y, Guo Q, Chen C, Wang Y. Coal-nitrogen release and NO_x evolution in the oxidant-staged combustion of coal. Energy, 2017, 125: 417–426

[8] Zhang K, Li Y, Yuan T, Cai J, Glarborg P, Qi F. An experimental and kinetic modeling study of premixed nitromethane flames at low pressure. Proceedings of the Combustion Institute, 2011, 33(1): 407–414

[9] Ye C, Wang Q, Zheng Y, Li G, Zhang Z, Luo Z. Techno-economic analysis of methanol and electricity poly-generation system based on coal partial gasification. Energy, 2019, 185: 624–632

[10] Peng Z, Chen L H, Sun M H, Wu P, Cai C, Deng Z, Li Y, Zheng W H, Su B L. Template-free synthesis of hierarchically macro-mesoporous Mn-TiO₂ catalysts for selective reduction of NO with NH₃. Frontiers of Chemical Science and Engineering, 2018, 12(1): 43–49

[11] Xu M H, Yu D X, Yao H, Liu X W, Qiao Y. Coal combustion-generated aerosols: formation and properties. Proceedings of the Combustion Institute, 2011, 33(1): 1681–1697

[12] Zhang H, Jiang X M, Liu J X, Liu J G. Theoretical study on the reactions originating from solid char (N): radical preference and possible surface N₂ formation reactions. Industrial & Engineering Chemistry Research, 2019, 58(39): 18021–18026

[13] Hämäläinen J P, Aho M J, Tummavuori J L. Formation of nitrogen oxides from fuel-N through HCN and NH₃: a model-compound study. Fuel, 1994, 73(12): 1894–1898

[14] Molina A, Eddings E G, Pershing D W, Sarofim A F. Char nitrogen conversion: implications to emissions from coal-fired utility boilers. Progress in Energy and Combustion Science, 2000, 26(4): 507–531

[15] Adamczyk W P, Werle S, Ryfa A. Application of the computational method for predicting NO_x reduction within large scale coal-fired boiler. Applied Thermal Engineering, 2014, 73(1): 343–350

[16] Wang C A, Du Y, Jin X, Che D. Pyridine and pyrrole oxidation under oxy-fuel conditions. Energy Sources. Part A, Recovery, Utilization, and Environmental Effects, 2016, 38(7): 975–981

[17] Bacskay G B, Martoprawiro M, Mackie J C. The thermal decomposition of pyrrole: an ab initio quantum chemical study of the potential energy surface associated with the hydrogen cyanide plus propyne channel. Chemical Physics Letters, 1999, 300(3-4): 321–330

[18] Liu J, Zhang X L, Lu Q, Shaw A, Hu B, Jiang X Y, Dong C Q. Mechanism study on the effect of alkali metal ions on the formation of HCN as NO_x precursor during coal pyrolysis. Journal of the Energy Institute, 2019, 92(3): 604–612

[19] Liu J, Lu Q, Jiang X Y, Hu B, Zhang X L, Dong C Q, Yang Y P. Theoretical investigation of the formation mechanism of NH₃ and HCN during pyrrole pyrolysis: the effect of H₂O. Molecules (Basel, Switzerland), 2018, 23(4): 711–721

[20] Duan L, Zhao C, Zhou W, Qu C, Chen X. Investigation on coal pyrolysis in CO₂ atmosphere. Energy & Fuels, 2009, 23(7): 3826–3830

[21] Mackie J C, Colket M B, Nelson P F. Shock tube pyrolysis of pyridine. Journal of Physical Chemistry, 1990, 94(10): 4099– 4106

[22] Ikeda E, Mackie J C. Thermal decomposition of two coal model compounds—pyridine and 2-picoline. Kinetics and product distributions. Journal of Analytical and Applied Pyrolysis, 1995, 34(1): 47–63

[23] Hong X, Zhang T C, Zhang L D, Qi F. Identification of intermediates in pyridine pyrolysis with molecular-beam mass spectrometry and tunable synchrotron VUV photoionization. Chinese Journal of Chemical Physics, 2009, 22(2): 204–209

[24] Liang X R, Wang Q H, Luo Z Y, Zhang H, Li K K, Feng Y, Shaikh A R, Cen J M. Simulation of nitrogen transformation in pressurized oxy-fuel combustion of pulverized coal. RSC Advances, 2018, 8(62): 35690–35699

[25] Li X, Zhang S, Yang W, Liu Y, Yang H, Chen H. Evolution of NO_x precursors during rapid pyrolysis of coals in CO₂ atmosphere. Energy & Fuels, 2015, 29(11): 7474–7482

[26] Ninomiya Y, Dong Z B, Suzuki Y, Koketsu J. Theoretical study on the thermal decomposition of pyridine. Fuel, 2000, 79(3-4): 449–457

[27] Liu J, Zhang X L, Hu B, Lu Q, Liu D J, Dong C Q, Yang Y P. Formation mechanism of HCN and NH₃ during indole pyrolysis: a theoretical DFT study. Journal of the Energy Institute, 2020, 93(2): 649–657

[28] Liu J, Zhang X L, Lu Q, Shaw A, Hu B, Jiang X Y, Dong C Q. Mechanism study on the effect of alkali metal ions on the formation of HCN as NO_x precursor during coal pyrolysis. Journal of the Energy Institute, 2019, 92(3): 604–612

[29] Han X X, Chen B, Li Q Y, Tong J H, Jiang X M. Organic nitrogen conversion during the thermal decomposition of Huadian oil shale of China. Oil Shale, 2017, 34(2): 97

[30] Hu E, Zeng X, Ma D, Wang F, Yi X, Li Y, Fu X. Effect of the moisture content in coal on the pyrolysis behavior in an indirectly heated fixed-bed reactor with internals. Energy & Fuels, 2017, 31(2): 1347–1354

[31] Park D C, Day S J, Nelson P F. Nitrogen release during reaction of coal char with O₂, CO₂, and H₂O. Proceedings of the Combustion Institute, 2005, 30(2): 2169–2175

[32] Yang H K. Experimental study on N migration of biomass pyrolysis and gasification process in tubular furnace. Dissertation for the Master’s Degree. Anhui: University of Science and Technology of China, 2016, 32–37

[33] Tian F J, Yu J L, McKenzie L J, Hayashi J, Li C Z. Conversion of fuel-N into HCN and NH₃ during the pyrolysis and gasification in steam: a comparative study of coal and biomass. Energy & Fuels, 2007, 21(2): 517–521

[34] Frisch M, Trucks G W, Schlegel H B, Scuseria G E, Robb M A, Cheeseman J R, Scalmani G, Barone V, Mennucci B, Petersson G, Gaussian 09, Revision D. 01, Gaussian, Inc., Wallingford CT, 2009

[35] Becke A. Density–functional thermochemistry. III. the role of exact exchange. Journal of Chemical Physics, 1993, 98(7): 5648–5652

[36] Zhang X L, Li J, Yang W H, Blasiak W. Formation mechanism of levoglucosan and formaldehyde during cellulose pyrolysis. Energy & Fuels, 2011, 25(8): 3739–3746

[37] Zhang H, Jiang X M, Liu J X, Shen J. Theoretical study on the specific role of superfine char surface oxygen—NO consumption mechanism. Powder Technology, 2013, 249: 82–88

[38] Shinohara Y, Tsubouchi N. Effect of the electronic state on low-rank coals with Ca²⁺ ion exchange. Journal of Molecular Structure, 2020, 1218: 128544

[39] Zhan J H, Wu R C, Liu X X, Gao S Q, Xu G W. Preliminary understanding of initial reaction process for subbituminous coal pyrolysis with molecular dynamics simulation. Fuel, 2014, 134: 283–292

[40] Bagdžiūnas G, Ramanavičius A. Towards direct enzyme wiring: a theoretical investigation of charge carrier transfer mechanisms between glucose oxidase and organic semiconductors. Physical Chemistry Chemical Physics, 2019, 21(6): 2968–2976

[41] Liu S, Wu Y G, Zhou C S, Wu J M, Zhang Y L. Study on the CO formation mechanism during coal ambient temperature oxidation. Energies, 2020, 13(10): 2587

[42] Ling L X, Zhang R G, Wang B J, Xie K C. Density functional theory study on the pyrolysis mechanism of thiophene in coal. Journal of Molecular Structure THEOCHEM, 2009, 905(1-3): 8–12

[43] Beste A, Buchanan A III. Computational study of bond dissociation enthalpies for lignin model compounds. Substituent effects in phenethyl phenyl ethers. Journal of Organic Chemistry, 2009, 74(7): 2837–2841

[44] Mphahlele M J, Maluleka M M, Rhyman L, Ramasami P, Mampa R M. Spectroscopic, DFT, and XRD studies of hydrogen bonds in N-unsubstituted 2-aminobenzamides. Molecules (Basel, Switzerland), 2017, 22(1): 83–96

[45] Jiang X Y, Lu Q, Hu B, Liu J, Dong C Q, Yang Y P. A comprehensive study on pyrolysis mechanism of substituted β-O-4 type lignin dimers. International Journal of Molecular Sciences, 2017, 18(11): 2364–2377

[46] Lin J Y, Zhang S, Zhang L, Min Z H, Tay H L, Li C Z. HCN and NH₃ formation during coal/char gasification in the presence of NO. Environmental Science & Technology, 2010, 44(10): 3719–3723

[47] Li C Z, Tan L L. Formation of NO_x and SO_x precursors during the pyrolysis of coal and biomass. Part III. Further discussion on the formation of HCN and NH₃ during pyrolysis. Fuel, 2000, 79(15): 1899–1906

[48] Chang L, Xie Z, Xie K C, Pratt K C, Hayashi J I, Chiba T, Li C Z. Formation of NO_x precursors during the pyrolysis of coal and biomass. Part VI. Effects of gas atmosphere on the formation of NH₃ and HCN. Fuel, 2003, 82(10): 1159–1166

[49] Chang L P, Xie Z L, Xie K C. Study on the formation of NH₃ and HCN during the gasification of brown coal in steam. Process Safety and Environmental Protection, 2006, 84(6): 446–452

Acknowledgments

The authors thank the National Natural Science Foundation of China (Grant Nos. 51922040 and 51821004), China Postdoctoral Science Foundation (Grant No. 2019TQ0091), Grants from Fok Ying Tung Education Foundation (Grant No. 161051), and Fundamental Research Funds for the Central Universities (Grant Nos. 2020DF01, 2020 MS020, 2018ZD08) for financial support.

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11705-020-2024-8 and is accessible for authorized users.

RIGHTS & PERMISSIONS

2021 Higher Education Press