Incorporating Oxygen Uncoupling Kinetics into Computational Fluid Dynamic Simulations of a Chemical Looping System

Abstract

Chemical looping with oxygen uncoupling (CLOU) is a carbon‐capture technology that utilizes a metal oxide as an oxygen carrier to separate oxygen from air and releases gaseous O2 into a reactor where fuel is fed. Earlier experimental and simulated work has been performed on systems less than 1 MW. Previous work has been limited to one‐dimensional kinetic simulations. Literature kinetics were modified to work in a Barracuda‐VR simulation package. A simplified spreadsheet model was used to verify the Barracuda‐VR simulation adaption of the kinetics to previously published results. The simulated kinetics, literature models, and raw data matched well. The adapted kinetics were then incorporated into a 10 kW dual bubbling bed CLOU system three‐dimensional simulation. The simulations predicted carbon capture efficiency similar to that reported previously for similar systems. The solid circulation rate, temperature profile, and gas concentration profiles followed the expected trends. The overall three‐dimensional simulation of kinetics showed reasonable results for what has been previously reported.

A High-Pressure System for Studying Oxygen Reduction During Pt Nanoparticle Collisions

“…The voltammetric responses for ORR at Au (green curve) and Pt (black curve) microdisk electrodes (Fig. 2), show that in airsaturated phosphate buffer solutions (dissolved oxygen concentration ≈ 0.21 mM, based on O 2 -solubility data for pure water at 25 °C and 0.85 atm; atmospheric pressure estimated accounting for the ∼4500 ft altitude of the lab in which the measurements were performed), 34,35 a much larger overpotential is required to drive the reduction at Au than at Pt (−150 vs +250 mV onset potentials, respectively). This indicates that ORR is kinetically more favorable on Pt; however, both onset potentials are considerably more negative than the equilibrium potential of ORR (+0.583 V vs Ag/AgCl; see section 1 in Supporting Information (available online at stacks.iop.…”

Chemical-looping combustion: Status and research needs

“…Validated models have been used to simulate the effect of operating conditions on fuel conversion and determine optimal conditions for the design of a CLC unit. For example, operation in the turbulent regime is recommended in order to achieve full conversion of gaseous fuels [78], but the bubbling regime could also be feasible for solid fuels [79]. Theoretical calculations suggest that a solids inventory in the fuel-reactor in the 150-250 kg/MW th interval is feasible to fully convert gaseous fuels, whereas increasing these values to above 500-750 kg/MW th is not recommended for solid fuels in iG-CLC, even if the complete combustion is not still achieved.…”