(583e) Comparison of Cu-, Fe- and Ni- Based Oxygen Carriers for Chemical-Looping Combustion
AIChE Annual Meeting
2013
2013 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Poster Session: Catalysis and Reaction Engineering (CRE) Division
Wednesday, November 6, 2013 - 6:00pm to 8:00pm
Chemical-looping combustion (CLC) is the indirect combustion of
fossil fuels for power generation taking place in two reactors (a Reducer and
an Oxidizer) with inherent CO2 separation, which is accomplished in
the Reducer reactor using an oxygen carrier (metal oxide) instead of air. Oxygen
carriers in a CLC power plant are expected to be carbon-resistant, exhibit high
reaction rates and conversions, and be regenerative over successive cycles. Different
metal oxides have been proposed and tested as promising candidates for the CLC
process, for instance, CuO, NiO, Fe2O3 and Mn2O3.
In this study, Cu-, Fe-, and Ni- oxygen carriers, prepared via the incipient
wetness impregnation on Al2O3-SiO2 supports
are compared in terms of their reactivity, selectivity and stability. A
fixed-bed reactor (Figure 1) is used to test the oxygen carrier reactivity and
CO2 separation efficiency. A sample of the experiments of this work
and the model prediction for Ni-based CLC is presented in Figure 2. Physical
and chemical properties of the fresh and used samples, such as active metal
oxide loading, available phases, surface structure, surface area and pore
volume are characterized by TGA, XRD, SEM and BET, respectively.
Kinetic networks and parameters are presented for all three oxygen
carriers. A summary of the fixed-bed experimental data analyzed and utilized to
validate the proposed kinetic network, including all the relevant published
data for CLC with CH4 and Fe2O3 and CuO as the
oxygen carrier, is presented in Table 1 (for the kinetics of Ni-based oxygen
carriers, see [1]).
Table
1: CLC
fixed-bed units
In this presentation, operating conditions, design values and OC
characterization is presented for the three most common metal oxides and
natural gas. Implementation of the kinetic network in different fixed-bed units
of the various CLC laboratories will be shown.
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Figure 1: Fixed-bed chemical-looping setup used in this work. |
Figure 2: Chemical-looping reduction selectivity using Ni/NiO and CH4 in fixed-bed reactors; experimental data from UConn fixed-bed reactor at 800°C. |
Acknowledgement:
This material is based upon work supported by the National Science Foundation
under Grant No. 1054718.
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