Oxygen release kinetics and mechanism study on Cu-, Co-, Mn-based oxygen carrier

Mei, Daofeng; Zhao, Haibo; Ma, Zhaojun; Yang, Wenyu; Fang, Yanfei; Zheng, Chenghang

doi:10.1016/s1872-5813(13)60016-x

Cited by 14 publications

(7 citation statements)

References 14 publications

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“…Gaseous oxygen is released from the reduced oxygen carrier, and this process is also reversible. Two of the most frequently used models to describe this type of reaction are the shrinking core model (SCM) and nucleation model. ,, The shrinking core model (SCM) assumes that the reaction takes place on the surface of a shrinking core and that no reaction is taking place throughout the interior of the core. A layer of solid product (reduced metal oxide) is formed around an unreacted core.…”

Section: Resultsmentioning

confidence: 99%

“…The activation energy of CuO oxygen uncoupling (reduction) versus the temperature range used in each study for kinetics available in the literature ,,,,− and in this work.…”

Section: Resultsmentioning

confidence: 99%

“…The CLC process has previously been studied for the combustion of both gaseous fuels (natural gas and syngas) − and solid fuels − for heat and power production. Solid fuel CLC is of significant interest due to the ability to use diverse carbonaceous feedstocks such as coal, pet coke, solid waste materials, or biomass.…”

Section: Introductionmentioning

confidence: 99%

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Examining and Modeling Oxygen Uncoupling Kinetics of Cu-Based Oxygen Carriers for Chemical Looping with Oxygen Uncoupling (CLOU) in a Drop Tube Fluidized Bed Reactor

et al. 2019

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Chemical looping combustion with oxygen uncoupling (CLOU) is a promising carbon capture and storage (CCS) technology for conversion of gaseous and solid hydrocarbon fuels where the release of gaseous O2 from an oxygen carrier is favored at high temperature and low O2 partial pressure. One promising CLOU material is the copper oxide redox system (CuO–Cu2O). The primary objective of this study was to examine the use of a drop tube fluidized bed reactor (DT-FBR) for evaluating the kinetics of oxygen uncoupling with Cu-based oxygen carriers. Appropriate rate expressions from redox experiments are needed to model and scale up CLOU systems. Additionally, the determined oxygen uncoupling kinetic parameters were validated using a computational fluid dynamic model. Two oxygen carriers consisting of 20 wt % CuO/Al2O3 and 9 wt % CuO/Al2O3 were prepared by physical mixing. A third oxygen carrier sample was prepared at 9 wt % CuO/Al2O3 by incipient wetness impregnation. The reaction rates of the copper oxide redox system are strongly dependent on thermodynamic effects of the oxygen partial pressure relative to the equilibrium oxygen partial pressure. The results presented in this paper offer an alternative and simplified kinetic analysis compared to that traditionally presented in the literature for the thermal reduction of copper oxide or other CLOU oxygen carriers. The reactor system used in this study allows for operating parameters to be adjusted, minimizing thermodynamic and mass transfer limitations, which eliminates the need for more complex kinetic/thermodynamic reaction models. The reaction kinetics measured in this study is compared based on the preparation method and the CuO weight percent loading. These results may aid in the development of CLOU technologies during reactor design and process modeling.

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Section: Resultsmentioning

confidence: 99%

“…The activation energy of CuO oxygen uncoupling (reduction) versus the temperature range used in each study for kinetics available in the literature ,,,,− and in this work.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Examining and Modeling Oxygen Uncoupling Kinetics of Cu-Based Oxygen Carriers for Chemical Looping with Oxygen Uncoupling (CLOU) in a Drop Tube Fluidized Bed Reactor

et al. 2019

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“…To attain the global apparent reaction kinetics, it is necessary to ensure that the test condition is mostly if not exactly the same as the actual reaction unit (because the apparent reaction kinetics is not universal and cannot be extrapolated), which, however, is usually not easy to be achieved in experiments. The testing methods used in reaction kinetics studies include the isothermal method ,, and the non-isothermal method. ,,, In the isothermal method, the reaction between the oxygen carrier and fuel gas can be easily triggered by switching the reaction atmosphere after a temperature rising period under the inert gas environment. This method holds the advantage of simplicity and accuracy in data processing and was adopted by most researchers.…”

Section: Microcosmic Reaction Mechanism and Redox Reaction Kineticsmentioning

confidence: 99%

Chemical Looping Combustion of Coal in China: Comprehensive Progress, Remaining Challenges, and Potential Opportunities

Zhao

Tian

et al. 2020

Energy Fuels

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Chemical looping combustion (CLC) has emerged as an efficient and promising combustion technique for fossil fuels during the past few decades. The main advantages of CLC lie in its inherent CO 2 sequestration and cascade energy utilization, being primarily benefited from the in situ reactive separation facilitated by the circulation of a solid intermediate. Up to date, the research on the CLC-related oxygen carrier, reactor, and system has made extensive and in-depth development worldwide. CLC units with thermal power ranging from the kW th to MW th scale were demonstrated with fuels of different types (gaseous, liquid, and solid fuels). Over the past 20 years, Chinese researchers have made significant progress in chemical looping technologies, extending from fundamental oxygen carrier studies to the implementation of pilot-scale CLC units. For the use of solid fuels, such as coal, in CLC, it is a rather challenging task but a lot of opportunities also remain. As a result of the particular "rich coal, meager oil, and deficient gas" energy reserve characteristics, China has become the main research battlefield on CLC of coal these years. In this paper, the main advances and research status on CLC of coal in China are reviewed and appraised. The contents in this paper cover most of, if not all, the research hotspots on CLC of coal, i.e., oxygen carrier screening, reactor design/construction/operation, pollutant emission, reaction kinetics, and numerical simulation. Chinese researchers have made substantial contributions to two bottleneck issues faced by the coal-derived CLC technique, i.e., developing and preparing a low-cost while well-performing oxygen carrier and promoting the slow char gasification process in the fuel reactor. In addition, remaining challenges that constrain the development of large-scale CLC units and indeed deserve in-depth investigation are analyzed. Particular attention is paid to the following three key challenges: severe mismatch of reaction rates in CLC of coal, difficulty in attaining a good balance between the oxygen carrier performance and cost, and challenge in controlling solid circulation to manage heat and mass transfer. Accordingly, potential opportunities for future research and scaling-up of the coal-derived CLC technique are discussed. The academic thoughts that are highlighted here include (1) achieving a good compromise between the oxygen carrier cost and performance through the rational design of a multifunctional and composite oxygen carrier and its scalable preparation using cheap raw materials, (2) coordination among reactor modeling− reactor design−reactor operation to attain effective management of heat and mass transfer in the CLC reactor, and (3) a complex while effective matching matrix among coal type, oxygen carrier particle, and reactor configuration to acquire the optimal performance of the whole CLC system. Overall, this review summarizes the contributions of Chinese scholars to CLC of coal and presents how these research achievements benefit the commercial-sca...

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“…5 Many OCs have been investigated in thermogravimetric analyzer (TGA), 6,7 batch fixed/fluidized bed reactors, 8,9 and interconnected fluidized bed reactors. 10−13 Some kinds of OC were synthetic oxides (like Ni-, 14 Fe-, 15,16 Cu-, 17−19 Co-, 20 Mn-based 21 oxides), and some were natural ores such as hematite, 22 ilmenite, 23 manganese ore, 24 copper ore, 25 and the mixture of iron ore and copper ore. 26 The experimental results in TGA or batch-operated reactors provided useful information about, e.g., reduction and oxidation kinetics, which are essential for the design and operation of a real CLC reactor. 27 To further test the reactivity behavior of OCs during the continuously long-term operation as well as the feasibility of CLC technology, several groups have already built lab-scaled interconnected fluidized bed reactors, where the OCs continuously circulate in the units.…”

Section: Introductionmentioning

confidence: 99%

Continuous Operation of Interconnected Fluidized Bed Reactor for Chemical Looping Combustion of CH₄ Using Hematite as Oxygen Carrier

Tian

Wei

et al. 2015

Energy Fuels

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Chemical looping combustion (CLC) is a novel technology for CO2 capture with low energy penalty. This technique involves the operation of the interconnected fluidized bed reactors, within which solid oxygen carrier particles circulate to provide active lattice oxygen for fuel combustion. An interconnected fluidized bed reactor was tested using natural hematite as oxygen carrier and CH4 as fuel. The thermal power was between 1.00 and 1.50 kWth in the continuous operation of 100 h. During the operation, the CLC unit showed a good performance, in which the gas leakage varied between 1.81% and 3.20%, and the CH4 conversion of 81.3% at maximum and the carbon capture efficiency of over 90% were attained. The effects of operational parameters on the performance of the new CLC reactor were investigated. The results indicated that the CH4 conversion and CO2 yield were influenced by the reactor temperature, bed inventory per unit thermal power, and the flow rate of the fluidizing gas agent in the fuel reactor. After the whole tests, no sintering and agglomeration of used particles were observed, and the thermogravimetric analyzer results of used samples showed the reactivity of oxygen carrier was well maintained.

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Oxygen release kinetics and mechanism study on Cu-, Co-, Mn-based oxygen carrier

Cited by 14 publications

References 14 publications

Examining and Modeling Oxygen Uncoupling Kinetics of Cu-Based Oxygen Carriers for Chemical Looping with Oxygen Uncoupling (CLOU) in a Drop Tube Fluidized Bed Reactor

Examining and Modeling Oxygen Uncoupling Kinetics of Cu-Based Oxygen Carriers for Chemical Looping with Oxygen Uncoupling (CLOU) in a Drop Tube Fluidized Bed Reactor

Chemical Looping Combustion of Coal in China: Comprehensive Progress, Remaining Challenges, and Potential Opportunities

Continuous Operation of Interconnected Fluidized Bed Reactor for Chemical Looping Combustion of CH₄ Using Hematite as Oxygen Carrier

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Oxygen release kinetics and mechanism study on Cu-, Co-, Mn-based oxygen carrier

Cited by 14 publications

References 14 publications

Examining and Modeling Oxygen Uncoupling Kinetics of Cu-Based Oxygen Carriers for Chemical Looping with Oxygen Uncoupling (CLOU) in a Drop Tube Fluidized Bed Reactor

Examining and Modeling Oxygen Uncoupling Kinetics of Cu-Based Oxygen Carriers for Chemical Looping with Oxygen Uncoupling (CLOU) in a Drop Tube Fluidized Bed Reactor

Chemical Looping Combustion of Coal in China: Comprehensive Progress, Remaining Challenges, and Potential Opportunities

Continuous Operation of Interconnected Fluidized Bed Reactor for Chemical Looping Combustion of CH4 Using Hematite as Oxygen Carrier

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Continuous Operation of Interconnected Fluidized Bed Reactor for Chemical Looping Combustion of CH₄ Using Hematite as Oxygen Carrier