Chemically and physically robust, commercially-viable iron-based composite oxygen carriers sustainable over 3000 redox cycles at high temperatures for chemical looping applications

2017 ◽  
Vol 10 (11) ◽  
pp. 2318-2323 ◽  
Author(s):  
Cheng Chung ◽  
Lang Qin ◽  
Vedant Shah ◽  
Liang-Shih Fan
Keyword(s):  
Mechanical Stability ◽  
Chemical Reactivity ◽  
Low Cost ◽  
Oxygen Carrier ◽  
Chemical Looping ◽  
Titanium Oxides ◽  
Oxygen Carriers ◽  
Redox Cycles ◽  
Iron Based

A low-cost oxygen carrier material realized through an Al-based skeleton encapsulating iron–titanium oxides with long-term chemical reactivity and mechanical stability for commercial chemical looping applications.

scholarly journals Coal Chemical-Looping with Oxygen Uncoupling (CLOU) Using a Cu-Based Oxygen Carrier Derived from Natural Minerals

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1453 ◽  
Author(s):  
Ping Wang ◽  
Bret Howard ◽  
Nicholas Means ◽  
Dushyant Shekhawat ◽  
David Berry
Keyword(s):  
Solid Fuel ◽  
Low Cost ◽  
Oxygen Carrier ◽  
Fixed Bed ◽  
Xrd Analysis ◽  
Reaction Rates ◽  
Fixed Bed Reactor ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Redox Cycles

Chemical-looping with oxygen uncoupling (CLOU) is considered a promising technology to burn solid fuels with improved CO2 capture and has the potential to improve fuel conversion and reaction rates. Cu-based oxygen carriers (Cu-OC) are often used in solid fuel CLOU. This study focused on investigating Cu-OC derived from a natural mineral for solid fuel CLOU because of their potentially lower cost compared to synthetic OCs. Reactivity and recyclability of a natural ore-derived Cu-OC on coal char (Powder River Basin sub-bituminous coal) were studied at 900 °C in Ar and air using TGA-QMS and fixed-bed reactor-QMS for five cycles. Cu-OC was prepared by simply heating chalcopyrite in air. Chalcopyrite is one of the principle copper sulfide ores and one of the primary ores for copper. The prepared Cu-OC had primarily CuO and CuFe2O4 (CuOFe2O3) as active compounds based on XRD analysis and an oxygen capacity 3.3% from oxygen uncoupling. The carbon conversion efficiency Xc was 0.94 for reduction at a ratio of Cu-OC to char ϕ = 75 and the product gas was primarily CO2 with trace O2. The reactivities and the rates were similar for five redox cycles. These results indicate that the natural ore-derived material with low cost has potential as a competitive oxygen carrier in solid fuel CLOU based on its reactivity in this study.

scholarly journals Feasibility Study of an Iron-Based Composite Added with Al2O3/ZrO2 as an Oxygen Carrier in the Chemical Looping Applications

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 971
Author(s):  
Ching-Ti Kao ◽  
Cheng-Hsien Shen ◽  
Heng-Wen Hsu
Keyword(s):  
Relative Density ◽  
Feasibility Study ◽  
Spinel Phase ◽  
Oxygen Carrier ◽  
Dense Layer ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Redox Cycles ◽  
Iron Based ◽  
Crush Strength

The chemical looping process is a promising approach for carbon capture. Oxygen carriers play the crucial role of carrying oxygen between oxidation and reduction reactors. In this study, iron-based composites, added with alumina and zirconia, were used as the oxygen carriers. The feasibility study of these composites for chemical looping applications was then evaluated by measuring their properties, including mechanical properties, relative density, microstructures, crystal structure, and their capacity of oxygen. The results suggest that the addition of zirconia led the decrease of the bulk relative density and thus had a negative effect to both crush strength and attrition. Crush strength declined from 57 kgf to 26 kgf when using zirconia, replacing alumina, in an iron-based composite as the inner material. In addition, the phases in oxidizing and reducing reaction were also revealed. The formation of the spinel phase (FeAl2O4) was the major factor that altered the capacity of oxygen. It inhibited Fe2O3’s ability to be completely reduced to Fe and thus decrease the capacity of oxygen. The value was therefore decreased from 9.7% to 6.2% after 50 redox cycles in alumina addition composite. On the other hand, for the zirconia addition, all of the Fe2O3 could transform to Fe, which provided 8.5% of oxygen capacity after 50 redox cycles. A dense layer which was identified as the Fe2O3 in the bulk surface was observed in the samples reacted with 50 redox cycles. The proposed mechanism of the formation of Fe2O3 layer and its corresponding kinetic analysis was also revealed in this study.

The Sustainable Capability Research on Copper- and Iron-Based Oxygen Carrier

2010 ◽  
Vol 146-147 ◽  
pp. 1398-1401
Author(s):  
Lei Chen ◽  
Jing Jin ◽  
Hui Wei Duan
Keyword(s):  
Oxygen Carrier ◽  
Pure Oxygen ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Reaction Ratio ◽  
Iron Based ◽  
Reduction And Oxidation ◽  
The One ◽  
The Comparative Study ◽  
Better Than

Chemical-looping combustion (CLC) is a new kind of efficient method to separate CO2. At present, most of CLC research focuses on the development of oxygen carriers. The sustainable capability is the one of important standards to evaluate performance of oxygen carrier. The iron- based and copper- based oxygen carrier were chosen in this paper. The comparative study between the analytically pure oxygen carriers and the prepared oxygen carriers with Al2O3 were made according to the reactivity of reduction and oxidation. The data was obtained by the TGA, SEM and XRD. The results show that the prepared carriers with Al2O3 are greatly improved both in reaction ratio and sustainable capability, and Fe- based oxygen carrier is better than the Cu- based oxygen carrier in the sustainable capability.

scholarly journals Kinetic Behavior of Fabricated CuO/ZrO2 Oxygen Carriers for Chemical Looping Oxygen Uncoupling

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2156
Author(s):  
Young Ku ◽  
Chia-Wei Chang ◽  
Shr-Han Shiu ◽  
Hsuan-Chih Wu ◽  
Niels Michiel Moed
Keyword(s):  
Elevated Temperatures ◽  
Cupric Oxide ◽  
Oxygen Carrier ◽  
Fixed Bed ◽  
Reduction Rate ◽  
Fixed Bed Reactor ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Redox Cycles ◽  
Reduction And Oxidation

Chemical looping with oxygen uncoupling (CLOU) is an innovative alternative to conventional combustion. CuO/ZrO2 oxygen carriers were tested in this system for their effectiveness and resilience. Cupric oxide (CuO) was demonstrated to be a reliable oxygen carrier for oxygen-uncoupling with consistent recyclability even after 50 redox cycles in a thermogravimetric analyzer (TGA). The reduction of CuO to generate Cu2O and oxygen was observed to be improved markedly for experiments operated at higher temperatures; however, the oxidation of Cu2O by air to generate CuO was hindered for experiments carried out at elevated temperatures. The reduction rate of fabricated CuO/ZrO2 particles containing 40% CuO was enhanced with increasing temperature and decreased with increasing particle size for experiments operated in a fixed bed reactor. The geometrical contraction and Avrami-Erofe’ev models were demonstrated to be appropriate for describing the reduction and oxidation of CuO/ZrO2, respectively. The activation energies for the reduction and oxidation were determined to be 250.6 kJ/mol and 57.6 kJ/mol, respectively, based on experimental results in the temperature range between 850 and 1000 °C.

scholarly journals Development of Stable Oxygen Carrier Materials for Chemical Looping Processes—A Review

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 926
Author(s):  
Yoran De Vos ◽  
Marijke Jacobs ◽  
Pascal Van Der Voort ◽  
Isabel Van Driessche ◽  
Frans Snijkers ◽  
...  
Keyword(s):  
Oxygen Carrier ◽  
Synthesis Methods ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Term Stability ◽  
Long Term Stability ◽  
Carrier Materials ◽  
Attrition Resistance ◽  
Further Development

This review aims to give more understanding of the selection and development of oxygen carrier materials for chemical looping. Chemical looping, a rising star in chemical technologies, is capable of low CO2 emissions with applications in the production of energy and chemicals. A key issue in the further development of chemical looping processes and its introduction to the industry is the selection and further development of an appropriate oxygen carrier (OC) material. This solid oxygen carrier material supplies the stoichiometric oxygen needed for the various chemical processes. Its reactivity, cost, toxicity, thermal stability, attrition resistance, and chemical stability are critical selection criteria for developing suitable oxygen carrier materials. To develop oxygen carriers with optimal properties and long-term stability, one must consider the employed reactor configuration and the aim of the chemical looping process, as well as the thermodynamic properties of the active phases, their interaction with the used support material, long-term stability, internal ionic migration, and the advantages and limits of the employed synthesis methods. This review, therefore, aims to give more understanding into all aforementioned aspects to facilitate further research and development of chemical looping technology.

scholarly journals Using Low-Cost Iron-Based Materials as Oxygen Carriers for Chemical Looping Combustion

2011 ◽  
Vol 66 (2) ◽  
pp. 235-248 ◽  
Author(s):  
E. Jerndal ◽  
H. Leion ◽  
L. Axelsson ◽  
T. Ekvall ◽  
M. Hedberg ◽  
...  
Keyword(s):  
Low Cost ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Iron Based

Redox Stabilization Effect of TiO2 in Co3O4 as Oxygen Carrier for the Production of Hydrogen through POX and Chemical Looping Processes

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
Thelma De los Rios ◽  
Daniel Lardizabal Gutierrez ◽  
Virginia Collins Martínez ◽  
Alejandro López Ortiz
Keyword(s):  
Partial Oxidation ◽  
Oxygen Carrier ◽  
Initial Step ◽  
Continuous Exposure ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Redox Cycles ◽  
Strong Stabilization ◽  
Production Of Hydrogen ◽  
Stabilization Effect

Novel proposed processes for H2 production and energy generation such as partial oxidation of hydrocarbons (POX-MeO) and chemical looping process (CLP), respectively require the use of solid oxides as oxygen carriers. In POX-MeO the required oxygen for the partial oxidation of methane is provided by a transition metal oxide (MeO). First, H2 is produced through CH4+MeO = CO+H2+Me. Secondly, Me is re-oxidized through Me+O2 = MeO to regenerate the oxygen carrier. In the CL process, CH4 is being completely oxidized through CH2 + MeO = CO2 + H2O + Me producing heat and CO2 ready for sequestration. Finally, Me is re-oxidized using air to regenerate the Me back to MeO. In both processes the regenerated MeO is sent back to the initial step to result in a cyclic operation. Continuous exposure of MeO to Redox cycles frequently produces sinterization and MeO stabilization is needed to avoid loss of activity. The objective of this study is to investigate the stabilization effect of TiO2 in Co3O4 during Redox cycles to be used as an oxygen carrier using CoxTiOy type spinnels. Characterization of the synthesized samples included XRD, TPR, and SEM. Co2TiO4 and CoTiO3 spinnels were synthesized by solid state reaction. TGA and TPR Redox performance cycles of Co3O4 produced sintering, while results using a Co2TiO4 spinnel structure suggest a strong stabilization effect of TiO2 on Co. Ten Redox cycles using H2 and CH4 as reducing agents and a mixture of O2/N2 as oxidizer resulted in fixation of Co to TiO2 avoiding sintering.

Study of Iron-Based Alloys in Solid Oxide Fuel Cell Temperature and Atmosphere Conditions, Effect of a Silver-Coating

2011 ◽  
Vol 183 ◽  
pp. 9-16
Author(s):  
I. Aubert ◽  
J. Jumel ◽  
M. Tarek-Lamazouade ◽  
Julien Vulliet
Keyword(s):  
Mechanical Stability ◽  
Low Cost ◽  
Atomic Energy Commission ◽  
Oxidation Kinetic ◽  
Oxidation Mechanism ◽  
Silver Coating ◽  
Iron Based ◽  
Thermal Dilatation ◽  
Layer Composition

The French Atomic Energy Commission has developed a High Temperature Electrolyzer having an original coaxial architecture. Important elements are spring-like interconnects which allow to cope with thermal dilatation. Specifications of these components are low-cost, long term electrical conductivity achieved by chemical and mechanical stability. Potential candidates are iron-based alloys on which thin silver-coating may be deposited. In this paper we study the interaction of such systems with a mixture of hot vapour and hydrogen that is representative of the electrolyzer environment. Oxidation kinetic is measured by thermogravimetry. The oxide layer composition and morphology of tested samples are then investigated using Energy Dispersive Spectroscopy (EDS) and Auger Electron Spectroscopy (AES). These analyses demonstrate that hydrogen content strongly impacts the oxidation mechanism.

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