Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (11): 2717-2723.doi: 10.3866/PKU.WHXB201607271

• ARTICLE • Previous Articles     Next Articles

Synergetic Effect of Mercury Adsorption on the Catalytic Decomposition of CO over Perfect and Reduced Fe2O3[001] Surface

Ji-Hong LI1,Chang-Feng LIN1,Wu QIN1,*(),Xian-Bin XIAO1,Li WEI2,*()   

  1. 1 National Engineering Laboratory for Biomass Power Generation Equipment, School of Renewable Energy Engineering, North China Electric Power University, Beijing 102206, P. R. China
    2 State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, P. R. China
  • Received:2016-05-03 Published:2016-11-08
  • Contact: Wu QIN,Li WEI E-mail:qinwugx@126.com;weilihit@126.com
  • Supported by:
    the National Natural Science Foundation of China(51346001);the National Natural Science Foundation of China(51106051);Fundamental Research Funds for the Central Universities, China(2016YQ07);Fundamental Research Funds for the Central Universities, China(2014ZD14)

Abstract:

Mercury emission from coal during chemical-looping combustion (CLC) is an inevitable process, which can lead to adverse interactions with the surface of the oxygen carrier, thereby affecting the interfacial redox reactions. Density functional theory calculations were performed to investigate the mechanism of elemental mercury (Hg0) adsorption and the synergetic effect of Hg0 on the catalytic decomposition of CO over a perfect surface (Fe2O3[001]), as well as a series of reduced surfaces (Fe2O2.75, Fe2O2.5, Fe2O2.25, Fe2O1.625, Fe2O0.875, Fe2O0.375 and Fe) during a deep CLC process. In this study, Hg0 was physically adsorbed on to a perfect Fe2O3 surface, and then chemically adsorbed on to a series of reduced surfaces. The adsorption of Hg0 inhibited the formation of meaningful interactions between CO and Fe2O3[Fe2O2.75, Fe2O2.5 and Fe2O2.25] and hindered the efficient transport of oxygen to oxidize CO into CO2. In contrast, this process promoted the interactions between CO and Fe2O1.625[Fe2O0.875, Fe2O0.375, and Fe], favoring the catalytic decomposition of CO on these surfaces, which accelerated the carbon deposit reducing CLC efficiency. Rationally controlling the reduction degree of the oxygen carrier could therefore be used to either decrease the adsorption of Hg0 or depress the deposition of carbon, which are both crucial for the optimization of CLC processes.

Key words: Chemical looping combustion, Oxygen carrier, Mercury, CO2 capture, Density functional theory

MSC2000: 

  • O647