Kinetics of mixed copper–iron based oxygen carriers for hydrogen production by chemical looping water splitting

Oxygen carriers for biomass gasification are capable of absorbing oxygen from air and desorbing it in the gasifier. Based on thermodynamic equilibrium, copper, manganese, and cobalt oxides have the highest oxygen release capacities among the different oxygen carriers. These oxygen carriers were deposited on alumina via incipient wetness impregnation. The weight loss of the CuO-Cu 2 O carrier, as measured in a thermogravimetric analyzer, was 10 % while it was 7 % for the Co 3 O 4 -CoO couple and only 3 % for the Mn 2 O 3 -Mn 3 O 4 couple. The optimum operating temperature for the CuO oxygen carrier was 100 8C higher compared to the other two at 950 8C. A modified nuclei growth model (MNG) characterizes the weight loss/gain during the reduction-oxidation cycles. The reduction rate is 3 times higher at 875 8C compared to 825 8C while the oxidation rate decreases more than 10 times. The CuO carrier surface area decreased by 70 %, while it was 30 % and 60 % in the Co 3 O 4 and Mn 2 O 3 carriers, respectively. Cobalt has a lower tendency to sinter at high temperature compared to either copper or manganese and has a higher oxygen transport capacity and oxidation-reduction rates. Therefore, despite its higher cost and toxicity, it might be considered as a potential oxygen carrier especially for solid fuel gasification.

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“…Chiron and Patience [22] summarized various existing models. Chiron and Patience [22] summarized various existing models.…”

Section: Reduction and Oxidation Kineticmentioning

confidence: 99%

TGA and kinetic modelling of Co, Mn and Cu oxides for chemical looping gasification (CLG)

2014

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“…The advantage of this configuration over other processes is that it produces energy and syngas simultaneously. Other studies have focused on hydrogen and sacrificed the energy component of the technology when they proposed the chemical looping water splitter (CLWS) . The CLWS is limited thermodynamically: the net energy input, independent of the metal oxide, equals the enthalpy change of the combined steam‐methane reforming and water‐gas shift reaction.…”

Section: Resultsmentioning

confidence: 99%

“…We compared the energy balance (per moles of metal oxide) of the CLWS to that of the CLC with a water splitter and carbon dioxide reductor (CLC/CR/WS) (Table ). For this analysis, we selected copper, iron, and manganese oxides, which have been tested in chemical looping, and for which the carbon reduction and/or water splitting activities are available …”

Section: Resultsmentioning

confidence: 99%

“…Volatile oxides are used in solid‐vapour thermochemical

{CO}_{2}

reduction and water splitting cycles, among them Zn/ZnO at 350 °C, as well as

{SnO}_{2}

/SnO . Fe‐, Cu‐, and mixed Cu‐Fe can split water, with a maximum of 0.2

{mol \cdot italickg}^{- 1}

hydrogen production . The U.S. Department of Energy identified copper chloride, ferrite, zinc, and manganese oxide as candidates for solar thermochemical hydrogen production at a target cost of 6

dollar / kg

…”

Section: Introductionmentioning

confidence: 99%

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Chemical looping syngas from CO₂ and H₂O over manganese oxide minerals

Perreault

Patience

2016

Can J Chem Eng

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Rather than sequestering carbon dioxide from the exhaust of chemical looping combustion reactors, together with the water, it could be used as a source of syngas. For the first time, we split water to hydrogen and carbon dioxide to carbon monoxide with a manganese ore. Specific CO production is 10–100 times higher than Sr, Ce, and Fe doped perovskites and Y0.5Sr0.5MnO3 perovskites. At a contact time of 0.01 s and at temperatures ranging from 810–960 °C the maximum specific CO production was 5.5 mol·italickg−1. A combined kinetic‐axial dispersion hydrodynamic model accounts for 97 % of the variance in the data assuming the reaction rate is first‐order in CO2 and surface reduced sites and in equilibrium with the reverse reaction—a first‐order reaction in CO with surface oxidized sites. A second reaction accounts for the diffusion of surface oxygen to the bulk lattice. Hydrogen productivity peaked at 4.8 mol·italickg−1 at 947 °C, which is twice as high as reported in previous studies on CoFe2O4 and Al2O3 in the hercynite cycle.

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“…The bulk kinetic reaction approach for modeling the reactor scale systems is described here. Experimental investigations of reaction kinetics are typically performed using thermogravimeters [64][65][66][67][68][69][70][71][72] or laboratory scale reactors, including fluidized beds [73][74][75], stabilized beds [76][77][78], and monolithic structured reactors [79][80][81][82][83]. Reaction kinetic modeling associated with each of these practices requires special attention to the corresponding experimental conditions.…”

Section: Kinetics Of High-temperature Solar Reactionsmentioning

confidence: 99%

Review of Heat Transfer Research for Solar Thermochemical Applications

Lipiński¹,

Davidson

Haussener

et al. 2013

Journal of Thermal Science and Engineering Applications

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This article reviews the progress, challenges and opportunities in heat transfer research as applied to high-temperature thermochemical systems that use high-flux solar irradiation as the source of process heat. Selected pertinent areas such as radiative spectroscopy and tomography-based heat and mass characterization of heterogeneous media, kinetics of high-temperature heterogeneous reactions, heat and mass transfer modeling of solar thermochemical systems, and thermal measurements in high-temperature systems are presented, with brief discussions of their methods and example results from selected applications.

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Kinetics of mixed copper–iron based oxygen carriers for hydrogen production by chemical looping water splitting

Cited by 50 publications

References 34 publications

TGA and kinetic modelling of Co, Mn and Cu oxides for chemical looping gasification (CLG)

TGA and kinetic modelling of Co, Mn and Cu oxides for chemical looping gasification (CLG)

Chemical looping syngas from CO₂ and H₂O over manganese oxide minerals

Review of Heat Transfer Research for Solar Thermochemical Applications

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Kinetics of mixed copper–iron based oxygen carriers for hydrogen production by chemical looping water splitting

Cited by 50 publications

References 34 publications

TGA and kinetic modelling of Co, Mn and Cu oxides for chemical looping gasification (CLG)

TGA and kinetic modelling of Co, Mn and Cu oxides for chemical looping gasification (CLG)

Chemical looping syngas from CO2 and H2O over manganese oxide minerals

Review of Heat Transfer Research for Solar Thermochemical Applications

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Product

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Chemical looping syngas from CO₂ and H₂O over manganese oxide minerals