Density functional theory study on improved reactivity of alkali-doped Fe2O3 oxygen carriers for chemical looping hydrogen production

Feng, Yuchuan; Wang, Nana; Guo, Xueyi

doi:10.1016/j.fuel.2018.09.079

Cited by 46 publications

(24 citation statements)

References 49 publications

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“…There is (i) an air reactor in which the oxygen carrier is completely oxidized by air, (ii) a fuel reactor where natural gas is oxidized to produce a stream of CO 2 and H 2 O delivering the main energy to the system, and (iii) a steam reactor where the oxygen carrier is partly regenerated by steam with the production of pure H 2 [112][113][114]. By regulating the mass flows of the oxygen carriers, maintaining the right equilibrium between the conversions in the three reactors, an autothermal process can be obtained, and high purity CO 2 and H 2 streams can be simultaneously obtained by condensation, without costly energy consumption for separation and purification [115]. Considering the high O 2 carrying capacity, good reactivity with H 2 O, and the low cost, Fe-based materials have been identified to be the most preferred oxygen carrier options for the chemical looping for hydrogen generation processes [111,[116][117][118] because they show high reactivity in the water-splitting reaction [40,41,119].…”

Section: Chemical Looping Hydrogen Generationmentioning

confidence: 99%

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

et al. 2020

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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.

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Section: Chemical Looping Hydrogen Generationmentioning

confidence: 99%

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

et al. 2020

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“…194 The DFT calculations conducted by Guo et al confirm that other dopants, including alkali dopants (Li, Na, and K), alkaline earth metals (Mg), transition metals (Ni, Cu, Zn, and Zr), and rare earth metals (La and Ce), can greatly improve the deep reducibility of Fe 2 O 3 as well. 179,195 Other iron-containing mixed OCs, mainly including Ni−Fe and Cu− Fe mixed oxides, are also employed for the CL-SRM process. From the combination of the advantages of Ni species for CH 4 activation and Fe species for water splitting, Liu et al obtain the high CH 4 conversion (up to 97.5%), CO selectivity (up to 92.9%), and H 2 productivity (29.0 mol kg −1 ) on the binary Ni−Fe catalyst.…”

Section: Chemical Looping Reforming Of Methanementioning

confidence: 99%

Chemical Looping Conversion of Gaseous and Liquid Fuels for Chemical Production: A Review

Xing-yun

et al. 2020

Energy Fuels

107

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Chemical looping technology enables achievement of the simultaneous feedstock conversion and product separation without additional processes via circulating solid intermediates (so-called oxygen/nitrogen carriers) in a redox process, which contributes to the improvement of product selectivity and energy conservation. In general, methane, CO 2 , N 2 , ethane, propane, ethanol, and glycerol are typical gaseous and liquid fuels for producing syngas, pure H 2 , pure CO, NH 3 , ethylene, and propylene via the chemical looping process. Central to this technology is the solid intermediates that act as reservoirs for storing and releasing O or N in multiple sub-reactions to close the loop. This work comprehensively describes the chemical looping conversion of gaseous or liquid fuels for chemical production, covering chemical looping reforming of methane, chemical looping oxidative coupling of methane, chemical looping reforming of liquid fuels, chemical looping oxidative dehydrogenation, and chemical looping ammonia synthesis technologies. Specifically, this review mainly focuses on the development of oxygen/nitrogen carrier materials, especially the related research in China. The effects of composition, structure, and morphology on the performance and related reaction mechanisms are discussed.

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“…The lack of oxygen carriers (OCs) which could efficiently produce stable hydrogen has been the main obstacle to the development of CLH. At present, the main types of CLH OCs are Fe‐based OCs, Ni‐based OCs, Cu‐based OCs, perovskite OCs, and composite metal‐based OCs 12,14,16‐20 . Through the complementary characteristics of elements, composite metal‐OCs can not only improve oxygen carrier's reactivity and stability but also the reduction of carbon deposition.…”

Section: Introductionmentioning

confidence: 99%

“…The combination of different metals can form some unique structures, such as spinel and perovskite, especially the iron‐based composite metal‐oxygen carrier (MFe 2 O 4 , M = Ni, Cu, Co, Mn) exhibits excellent oxygen‐carrying capacity and redox reactivity. OCs based on these spinel materials are widely used in the chemical looping process 17,21‐25 . Huang et al 26 studied an iron‐based oxygen carrier doped with Ni.…”

Section: Introductionmentioning

confidence: 99%

Study on the reaction performance of Ce‐doped NiFe ₂ O ₄ oxygen carriers in the process of chemical looping hydrogen production

Gao

Wang

et al. 2021

Intl J of Energy Research

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Summary Chemical looping hydrogen production is a kind of hydrogen production technology with great potential. NiFe2O4 is one of the oxygen carriers with the best comprehensive hydrogen production performance, but the oxygen carrier still has the disadvantages of low hydrogen production and poor reaction stability. In this paper, a small amount of Ce was doped in the oxygen carrier to improve the hydrogen production efficiency. And the reaction stability of the oxygen carrier was improved by loading an inert carrier. The experimental results showed that the 6 wt% Ce‐NiFe2O4 oxygen carrier had the highest H2 yield, and the hydrogen yield per unit mass of oxygen carrier was increased from 194 to 367 mL/g. Thermodynamic simulation and characterization results showed that the doping of Ce could enhance the oxygen release capacity and hydrogen production capacity. In the cyclic experiment, due to the damage of the oxygen carrier spinel structure and the sintering of oxygen carrier particles, the reaction activity of the 6 wt% Ce‐NiFe2O4 oxygen carrier gradually reduced and the hydrogen production in the steam reactor decreased significantly after 15 cycles. After the loading of Al2O3 inert support on the 6 wt% Ce‐NiFe2O4 oxygen carrier, the hydrogen production was greatly improved and remained stable after 15 cycles. The modification of the oxygen carrier could not only increase the hydrogen production but also the economic efficiency for the reduced amount of Ce and Ni.

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Density functional theory study on improved reactivity of alkali-doped Fe2O3 oxygen carriers for chemical looping hydrogen production

Cited by 46 publications

References 49 publications

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

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

Chemical Looping Conversion of Gaseous and Liquid Fuels for Chemical Production: A Review

Study on the reaction performance of Ce‐doped NiFe ₂ O ₄ oxygen carriers in the process of chemical looping hydrogen production

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Density functional theory study on improved reactivity of alkali-doped Fe2O3 oxygen carriers for chemical looping hydrogen production

Cited by 46 publications

References 49 publications

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

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

Chemical Looping Conversion of Gaseous and Liquid Fuels for Chemical Production: A Review

Study on the reaction performance of Ce‐doped NiFe 2 O 4 oxygen carriers in the process of chemical looping hydrogen production

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Study on the reaction performance of Ce‐doped NiFe ₂ O ₄ oxygen carriers in the process of chemical looping hydrogen production