J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (12): 2375-2383.DOI: 10.1016/j.jmst.2018.04.011

• Orginal Article • Previous Articles     Next Articles

Cell-protecting regeneration from anode carbon deposition using in situ produced oxygen and steam: A combined experimental and theoretical study

Zongying Hanabc, Zhibin Yanga, Minfang Hanab*()   

  1. a Union Research Center of Fuel Cell, School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, China
    b Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China
    c College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao, 266590, China
  • Received:2017-12-06 Revised:2018-01-12 Accepted:2018-01-29 Online:2018-12-20 Published:2018-11-15
  • Contact: Han Minfang

Abstract:

Carbon deposition is a primary concern during the operation of solid oxide fuel cells (SOFCs) fueled with hydrocarbon fuels, leading to cell degradation and even cell damage. Carbon elimination is expected to be a promising approach to prolong cell life. This work reports on a combined experimental and theoretical investigation of cell regeneration from anode carbon deposition of tubular SOFCs fabricated by phase-inversion and co-sintering techniques. The as-prepared cell exhibits a maximum power density of 0.20?W?cm-2 at 800?°C fueling with wet CH4, but fails to stable operation due to severe carbon deposition. Based on thermodynamic predictions, a successive cell-protecting regeneration process is proposed to eliminate deposited carbon without oxidizing Ni catalysts, during which CH4 and H2 fuels are provided in circulation. Through a total of 35 cycling tests, cell performance can always successfully restore to the initial level. The possible carbon elimination mechanism is investigated in detail based on thermodynamic and first-principle calculations. The feasibility of carbon elimination using in situ produced oxygen or steam through electrochemical reaction has been revealed, providing a novel continuous operation mode for hydrocarbon-based SOFCs.

Key words: Solid oxide fuel cells, Carbon deposition, Cell regeneration, Carbon elimination, First-principle