Investigation of Oxygen Diffusivity within Oxygen Carrier In Chemical Looping Process

  • Type:
    Conference Presentation
  • Skill Level:
    Intermediate
  • PDHs:
    0.50

Share This Post:

You will be able to download and print a certificate for these PDH credits once the content has been viewed. If you have already viewed this content, please click here to login.

Chemical looping process is effective in converting carbonaceous fuels into hydrogen and electricity while generating a sequestration-ready CO2 stream. The process scheme is enabled by the cyclic reduction and oxidation reactions of an oxygen carrier (OC). The properties of OCs are of critically importance for the performance of chemical looping process. Our previous experimental studies show that composite iron oxide synthesized by adding support materials to the pure iron oxide can serve as good OCs. Unlike the unsupported iron oxide which deactivates within the first few redox cycles, the composite iron oxide maintains good reactivity over a long time although pore volume decreases significantly in the first few cycles. This phenomenon indicates that traditional understanding on support effect, mainly based on morphological analysis, may not be accurate. In this study, we investigated the role of support through both marker experiments and periodic Density Functional Theory (DFT) calculations. Ilmenite (FeTiO3) was used to model the simplified TiO2 supported iron (II) oxide material. Both the oxygen diffusion barrier and vacancy formation energy in ilmenite (FeTiO3) and wustite (Fe1-xO) were calculated. The diffusivities of oxygen in both materials were estimated based on the calculation results. It was found that the energy barrier for oxygen anion diffusion in ilmenite was significantly lower than that in wustite. The calculated oxygen diffusivity in ilmenite was also higher. This finding was corroborated by the marker experiment which indicates notably enhanced oxygen anion conductivity in the supported iron oxide.

Please Note: Members of the Transport and Energy Processes Division of AIChE are entitled to this content for free. Simply enter the 'promo code' TEPCOD when you are checking out. Only AIChE members are entitled to join the Transport and Energy Processes Division. For more info please click here. click here
Siwei Luo
Presenter(s): 
__

Checkout

Checkout

Do you already own this?

Log In for instructions on accessing this content.

AIChE MEMBERS

AIChE Member Credits 0.5
AIChE Members $15.00
AIChE Undergraduate Student Members Free
AIChE Graduate Student Members Free
Non-Members $25.00