Isothermal Reaction of NiO Powder with Undiluted CH4 at 1000 K to 1300 K (727 °C to 1027 °C)

Altay, Melek Cumbul; Eroglu, S.

doi:10.1007/s11663-017-0991-z

Cited by 7 publications

(8 citation statements)

References 20 publications

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“…In general, the modeling of obtained kinetic data of the reduction reactions does not always provide an accurate description of the mechanism due to the complex nature of the process. For example, NiO + CH 4 reaction kinetics can be well described by several models such as nucleation–growth, , geometrical contraction, or random pore . Therefore, we combined kinetic modeling with ex situ microscopy analysis of rapidly arrested microstructures to understand the direct links between the reaction kinetics and microstructural transformations.…”

Section: Discussionmentioning

confidence: 99%

“…Altay and Eroglu reported isothermal investigation of NiO reduction with a flowing undiluted CH 4 at the 1000–1300 K range . NiO reduction forms Ni particles which accelerate the deposition of pyrolytic carbon at 1200–1300 K. The authors assumed that NiO reduced by H 2 which releases during homogeneous gas-phase decomposition of methane.…”

Section: Introductionmentioning

confidence: 99%

“…Despite extensive investigations ,,,,,, of NiO reduction by methane, many questions remain about its kinetics and molecular and structural transformation mechanisms. The carbon deposition, however, limits the kinetic measurement of NiO reaction with CH 4 . , Nonisothermal experiments with low heating rates (25 K/min) showed that reduction starts at ∼625 K and the full conversion can be achieved at ∼1000 K, while further heating results in pyrolytic carbon deposition . The use of diluted CH 4 allows overcoming such difficulty in kinetic measurements.…”

Section: Introductionmentioning

confidence: 99%

“…36,37 From 15% to 65% Altay and Eroglu reported isothermal investigation of NiO reduction with a flowing undiluted CH 4 at the 1000−1300 K range. 33 NiO reduction forms Ni particles which accelerate the deposition of pyrolytic carbon at 1200−1300 K. The authors assumed that NiO reduced by H 2 which releases during homogeneous gas-phase decomposition of methane. The reaction kinetics was reasonably well described by nucleation−growth and geometrical contraction models, with calculated activation energies of 103 and 111 kJ/mol, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics and Mechanism of Nickel Oxide Reduction by Methane

2019

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Nickel oxide reduction by methane is of particular importance in catalysis, extractive metallurgy, and clean power generation technologies. Despite extensive investigations of the NiO + CH 4 reaction, many questions remain about its kinetics and molecular and structural transformation mechanisms. This work reports the reduction kinetics of bulk polycrystalline NiO by CH 4 using a new calorimetric method. The method permits rapid, controllable heating of the NiO/Ni wires and continuous data (electrical power, the electrical resistivity of the wire, and temperature) acquisition with a frequency of 10 kHz. The method also allows arresting and preservation of the structure of the sample by programmed termination of electric power in thin specimens. This approach, coupled with ex situ electron microscopy, allows determination of the reaction rate and tracking of the ongoing structural transformations. The mechanism of NiO reduction by methane is suggested based on direct correlations between reaction kinetics and the observed microstructure transformations. The kinetic data treatment revealed that the nucleation−growth model describes the reaction kinetics. Ex situ microscopy observations of reacted specimens showed that the first nuclei rapidly accelerate the process. Pore formation occurs at the nucleation sites, and the porous structure then quickly grows into the bulk NiO. The second type of reduced Ni microstructure, compact layer, can be observed only on the outer surface of the wire. Based on kinetic data and microstructural observations, a mechanism of reduction was suggested according to which porous microstructure forms predominantly by NiO reduction with carbon. The compact layer observed on the outer surface of the wire forms through the diffusion-controlled hydrogen reduction.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Kinetics and Mechanism of Nickel Oxide Reduction by Methane

2019

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“…Eroglu and coworkers thermodynamically studied and experimentally demonstrated the feasibility of MR of SnO 2 method 42 . They also utilized methane as a reducing agent of various metal oxides 43 , 45 , 49 confirming the strong reducing power of methane. However, detailed atomic scale understanding of MR of SnO 2 , which is necessary for optimization of the MR reduction method, is scarce.…”

Section: Introductionmentioning

confidence: 86%

Design of Reduction Process of SnO2 by CH4 for Efficient Sn Recovery

Yoo

et al. 2017

Sci Rep

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We design a novel method for the CH4 reduction of SnO2 for the efficient recovery of Sn from SnO2 through a study combining theory and experiment. The atomic-level process of CH4-SnO2 interaction and temperature-dependent reduction behavior of SnO2 were studied with a combination of a multi-scale computational method of thermodynamic simulations and density functional theory (DFT) calculations. We found that CH4 was a highly efficient and a versatile reducing agent, as the total reducing power of CH4 originates from the carbon and hydrogen of CH4, which sequentially reduce SnO2. Moreover, as a result of the CH4 reduction of SnO2, a mixture of CO and H2 was produced as a gas-phase product (syngas). The relative molar ratio of the produced gas-phase product was controllable by the reduction temperature and the amount of supplied CH4. The laboratory-scale experimental study confirmed that CH4 actively reduces SnO2, producing 99.34% high-purity Sn and H2 and CO. Our results present a novel method for an efficient, green, and economical recycling strategy for Sn with economic value added that is held by the co-produced clean energy source (syngas).

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Synthesis of Tin Powder Using Tin Oxide and Ethanol

Çetinkaya

Eroglu

2018

JOM

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Isothermal Reaction of NiO Powder with Undiluted CH4 at 1000 K to 1300 K (727 °C to 1027 °C)

Cited by 7 publications

References 20 publications

Kinetics and Mechanism of Nickel Oxide Reduction by Methane

Kinetics and Mechanism of Nickel Oxide Reduction by Methane

Design of Reduction Process of SnO2 by CH4 for Efficient Sn Recovery

Synthesis of Tin Powder Using Tin Oxide and Ethanol

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