(551d) Continuous Regime of Clc/CLOU Reactivity and Its Impact on the Dynamic and Steady State Performance of CuxOy Oxygen Carriers

A detailed kinetic network that captures the continuous regime of
Cu-based oxygen carrier reactivity in chemical-looping combustion (CLC) and/or
chemical-looping with oxygen uncoupling (CLOU) processes is used to study
transient and steady state process efficiencies. Theoretical models for
CLC/CLOU processes and experimental facilities are utilized for this analysis.
The transient kinetics of Cu-based oxygen carriers in the temperature range of
750 to 1000 °C was investigated in a fixed-bed reactor (Figure 1), supported by
supplementary characterization techniques, such as TGA, SEM and in-situ
hot-stage XRD (Figure 2). The continuous regime between CLC and CLOU, as
studied experimentally and theoretically is shown in Figure 3. The effect of
operating pressure on the reaction kinetics was also investigated for the
purpose of predicting syngas CL processes integrated in IGCC power/hydrogen
plants. The established kinetic network is then implemented in different
process models to evaluate system performance. The transient behavior of
CLC/CLOU is simulated by a hydrodynamic three-phase (bubble, emulsion and wake)
model in a fluidized bed reactor, while Aspen Plus process flowsheet
simulations are performed to study the steady state behavior. On the basis of
the developed Cu-based kinetics and process models, a comprehensive evaluation
of the real efficiency of Cu-based CL processes integrated in the power
generation infrastructure is carried out.

Acknowledgement:
This material is based upon work supported by the National Science Foundation
under Grant No. 1054718.

 

Figure 3: Model prediction and experimental data of (a)
chemical-looping combustion selectivity and (b) chemical-looping with oxygen
uncoupling using Cu/CuO and CH₄/Ar in a fixed-bed reactor. Note:
model prediction at 825 °C (dashed line), 850 °C (solid line) and 980 °C
(dotted line); experimental data at 825 °C (diamond), 850 °C (circle) and 980
°C (star).