545549 High-Efficient Chemical/Electrochemical CH4 Conversion

Monday, June 3, 2019: 3:06 PM
Republic ABC (Grand Hyatt San Antonio)
Yongdan Li, Tianjin Key Laboratory of Applied Catalysis Science and Technology, Tianjin University, Tianjin, China; Chemical Engineering and Technology, Tianjin University, Tianjin, China

Natural gas, which is mainly CH4, is one of the most important fossil fuels in the world. Nowadays, large amount of natural gas is burned directly to drive turbines to generate electricity, which has a low efficiency and release enormous CO2. During the last two decades, we have been active and made a number of breakthroughs in high-efficient CH4 convension and utilization.

Hydrogen is an ideal clean energy source which has raised much attention. Most of the hydrogen supply is produced based on steam reforming and partial oxidation of hydrocarbons and carbonaceous feed stocks such as natural gas and coal. Those techniques also produce CO and CO2, requiring additional clean and sequestration processes. In 2000, we proposed a process to produce COx-free hydrogen and value-added carbon material simultaneously through methane catalytic decompostion (MCD) reaction1, which has become very attractive due to the simplicity in process flow sheet and high efficiency. The products are easily separated and the clean hydrogen obtained can be used without further purification. Since then, we have focused on the development of novel catalysts and new catalytic processes, and carbons with various structures such as nanotubes2, nanofibers3-6 and nonoonions7 were obtained. We developed a number of catalysts including Fe, Co and Ni suppored by Al2O3 and MgO8-11, and improved their activity and stability with optimize the precusor and with doping promoters such as start with Feitknecht Compound3, 12, and introduce ZnO13 and Na2O14. Meanwhile, the influences of the catalyst properities and the reaction conditions on the morphology of the nanocarbons have been revealed15-19. Afterwards, we proposed a high-efficient energy conversion system incorporating a MCD reactor with a direct carbon fuel cell consuming the carbon produced and an internal reforming solid oxide fuel cell (SOFC) with hydrogen and unconverted methane as the fuels20. In 2011, we summarized the effort and published a review article on the development of methane decomposition on group 8-10 base metal catalysts21.

Direct CH4 fuelled SOFC is a very promising clean technique to generate electricity with a high efficiency, and the development of novel anode materials with a high catalytic activity and high coking resistance is a key issue. In 2011, we developed a double-perovskite Sr2FeMoO6-δ anode with a high catalytic activity and sufficient mixed ionic-electronic conductivity22. A single cell supported by a 300 μm-thick La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) electrolyte layer exhibited a maximum power density (Pmax) of 600 mW cm-2 at 850 oC with dry CH4 as the fuel. Another CH4-fuelled single cell with Ni-Ce0.8Sm0.2O1.9 (SDC) cermet anode and 120 μm-thick SDC electrolyte layer showed a Pmax of 671 mW cm-2 at 700 oC23. The performance dropped 3.7% after the cell discharged at 600 oC for 72 h. An addition of a small amount of Sn in the anode showed a positive effect on the stability of the anode, and the performance drop of the cell decreased to 1.51%24. Besides Sn, we found that some other additives could also improve the resistance to carbon deposition of Ni-SDC anode with hydrocarbon fuels by the modification of crystal and electronic structure of Ni25-27. Furthermore, some basic additives such as NbO could adsorb water readily and facilitate carbon removal reactions28. Recently, we developed LaBaMn1.6Fe0.2Co0.2O5+δ as an anode material, and a single cell supported by the LSGM electrolyte layer achieved a Pmax of 500 mW cm-2 with a duration of more than 200 h at 850 oC with CH4 as the fuel.

Keywords: Methane catalytic decompostion; Carbon nanofiber; Solid oxide fuel cell; Anode

References

  1. Y.D. Li, J.L. Chen, Y.N. Qin, L. Chang, Energy Fuels, 2000, 14, 1188-1194.
  2. L.Y. Piao, Y.D. Li, J.L. Chen, L. Chang, J.Y.S. Lin, Catalysis Today, 2002, 74, 145-155.
  3. Y.D. Li, J.L. Chen, L. Chang, Applied Catalysis A: General, 1997, 163, 45-57.
  4. Y.D. Li, J.L. Chen, Y.M. Ma, J.B. Zhao, Y.N. Qin, L. Chang, Chemical Communications, 1999, 1141-1142.
  5. J.L. Chen,Y.D. Li, Y.M. Ma, Y.N. Qin, L. Chang, Carbon, 2001, 39, 1467-1475.
  6. X.X. Zhang, Z.Q. Li, G.H. Wen, K.K. Fung, J.L. Chen,Y.D. Li, Chemical Physics Letters, 2001, 333, 509-514.
  7. C.N. He, N.Q. Zhao, X.W. Du, C.S. Shi, J. Ding, J.J. Li, Y.D. Li, Scripta Materialia, 2006, 54, 689-693.
  8. J.L. Chen, X.Z. Zhou, L. Cao, Y.D. Li, Studies in Surface Science and Catalysis, 2004, 147, 73-78.
  9. G.W. Wang, Y. Jin, G.J. Liu, Y.D. Li, Energy Fuels, 2013, 27, 4448-4456.
  10. Y. Jin, G.W. Wang, Y.D. Li, Applied Catalysis A: General, 2012, 445-446, 121-127.
  11. G.W. Wang, J.L. Chen, Y. Tian, Y. Jin, Y.D. Li, Catalysis Today, 2012, 183, 26-33.
  12. Y.D. Li, J.L. Chen, L. Chang, Y.N. Qin, Journal of Catalysis, 1998, 178, 76-83.
  13. J.L. Chen, Y.H. Qiao, Y.D. Li, Applied Catalysis A: General, 2008, 337, 148-154.
  14. W.Z. Qian, T. Liu, F. Wei, Z.W. Wang, D.Z. Wang, Y.D. Li, Carbon, 2003, 41, 2683-2686.
  15. D.X. Li, J.L. Chen, Y.D. Li, International Journal of Hydrogen Energy, 2009, 34, 299-307.
  16. J.L. Chen, X.M. Li, Y.D. Li, Y.N. Qin, Chemistry Letters, 2003, 32, 424-425.
  17. L.Y. Piao, J.L. Chen, Y.D. Li, China Particuology, 2003, 1, 266-270.
  18. J.L. Chen, Q. Ma, T.E. Rufford, Y.D. Li, Z.H. Zhu, Applied Catalysis A: General, 2009, 362, 1-7.
  19. J.L. Chen, X. Yang, Y.D. Li, Fuel, 2010, 89, 943-948.
  20. Q.H. Liu, Y. Tian, H.J. Li, L.J. Jia, C. Xia, L.T. Thompson, Y.D. Li, Journal of Power Sources, 2010, 195, 6539-6548.
  21. Y.D. Li, D.X. Li, G.W. Wang, Catalysis Today, 2011, 162, 1-48.
  22. Z.M. Wang, Y. Tian, Y.D. Li, Journal of Power Sources, 2011, 196, 6104-6109.
  23. Z.M. Wang, Y.D. Li, J.W. Schwank, Journal of Power Sources, 2014, 248, 239-245.
  24. P. Li, Z.M. Wang, X.L. Yao, N.J. Hou, L.J. Fan, T. Gan, Y.C. Zhao, Y.D. Li, J.W. Schwank, Catalysis Today, 2018, DOI: 10.1016/j.cattod.2018.04.030.
  25. P. Li, B.L. Yu, J. Li, X.L. Yao, Y.C. Zhao, Y.D. Li, Journal of Power Sources, 2016, 320, 251-256.
  26. P. Li, L.N. Fang, N.J. Hou, J. Li, X.L. Yao, T. Gan, L.J. Fan, Y.C. Zhao, Y.D. Li, Journal of The Electrochemical Society, 2017, 164, F1142-F1148.
  27. G.C. Ding, T. Gan, J. Yu, P. Li, X.L. Yao, N.J. Hou, L.J. Fan, Y.C. Zhao, Y.D. Li, Catalysis Today, 2017, 298, 250-257.

28. X.L. Yao, L.J. Fan, T. Gan, N.J. Hou, P. Li, Y.C. Zhao, Y.D. Li, International Journal of Hydrogen Energy, 2018, 43, 12748-12755.


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