Kinetics of the reduction of nickel oxide by hydrogen

Bandrowski, J.; Bickling, C.R.; Yang, Kuo‐Ho; Hougen, O. A.

doi:10.1016/0009-2509(62)80039-6

Cited by 70 publications

(27 citation statements)

References 6 publications

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“…At low temperature, it was observed that the presence of steam delayed the reduction of NiO by H 2 at 295 ºC [384]. Nevertheless, at temperatures of interest for CLC, the H 2 O or CO 2 content does not affect the observed reduction rate in most of cases [27,126,200,218,232,296].…”

Section: Kinetic Datamentioning

confidence: 96%

Progress in Chemical-Looping Combustion and Reforming technologies

Adánez

Abad

Garcı́a-Labiano

et al. 2012

Progress in Energy and Combustion Science

1,999

1,614

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This work is a comprehensive review of the Chemical-Looping Combustion (CLC) and Chemical-Looping Reforming (CLR) processes reporting the main advances in these technologies up to 2010. These processes are based on the transfer of the oxygen from air to the fuel by means of a solid oxygen-carrier avoiding direct contact between fuel and air for different final purposes. CLC has arisen during last years as a very promising combustion technology for power plants and industrial applications with inherent CO 2 capture which avoids the energetic penalty present in other competing technologies.CLR uses the chemical looping cycles for H 2 production with additional advantages if CO 2 capture is also considered.The review compiles the main milestones reached during last years in the development of these technologies regarding the use of gaseous or solid fuels, the oxygen-carrier development, the continuous operation experience, and modelling at several scales. Up to 2010, more than 700 different materials based on Ni, Cu, Fe, Mn, Co, as well as other mixed oxides and low cost materials, have been compiled. Especial emphasis has been done in those oxygen-carriers tested under continuous operation in Chemical-Looping 2 prototypes. The total time of operational experience (≈ 3500 h) in different CLC units in the size range 0.3-120 kW th , has allowed to demonstrate the technology and to gain in maturity. To help in the design, optimization, and scale-up of the CLC process, modelling work is also reviewed. Different levels of modelling have been accomplished, including fundamentals of the gas-solid reactions in the oxygen-carriers, modelling of the air-and fuel-reactors, and integration of the CLC systems in the power plant. Considering the great advances reached up to date in a very short period of time, it can be said that CLC and CLR are very promising technologies within the framework of the CO 2 capture options.

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Section: Kinetic Datamentioning

confidence: 96%

Progress in Chemical-Looping Combustion and Reforming technologies

Adánez

Abad

Garcı́a-Labiano

et al. 2012

Progress in Energy and Combustion Science

1,999

1,614

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“…[8][9][10][11][12] The Arrhenius activation energies reported in these studies are summarized in Table I.…”

Section: Previous Workmentioning

confidence: 99%

“…The precursor compositions employed in the present work are marked in the Ni-W-O isothermal phase diagram computed for 1273 K by Thermo Calc (Calphad, Chicago, IL) presented in Figure 1. [20] 428-473 110 [8] 534-571 51.9 and 60.2 [9] 473-630 57.3 [10] 630-1173 53.1 [10] 673-1073 21.8 [11] 564-782 18 [12] Based on the XRD measurements, the unit cell parameter values for NiWO 4 precursor samples were evaluated. These results are presented in Table III. B.…”

Section: A Materialsmentioning

confidence: 99%

Kinetics of Reduction of NiO–WO3 Mixtures by Hydrogen

Ahmed

El-Geassy

Seetharaman

2009

Metall Mater Trans B

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The kinetics of reduction of the oxide mixtures of Ni-W with different Ni/(Ni-W) molar ratios within the range of 923 K to 1173 K in flowing hydrogen gas was investigated by means of thermogravimetric analysis under isothermal conditions. The products were examined by X-ray diffraction, scanning electron microscope (SEM), and electron dispersion spectroscopy (EDS) analyses. Five different oxide mixtures apart from the pure oxides were studied in the present work. The results indicate that the reduction reaction proceeds through three consecutive steps that are as follows:From the experimental results, the Arrhenius activation energies of the three steps were evaluated for all of the studied compositions. The activation energy for the first step was calculated to be approximately 18 kJ/mol. For the second and third stages, the activation energy values varied from 62 to 38 kJ/mol for the second stage and 51 to 34 kJ/mol for the third stage depending on the Ni/(Ni + W) molar ratio in the precursors; the activation energy increased with increasing ratios. SEM images showed that the grain size of the final product was dependent on the Ni/(Ni + W) molar ratio; smaller grains were formed at higher nickel contents.

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“…[3] Careful control and further improvements are needed to ensure these new targets are achieved in industrial practice. Many experimental studies have been carried out to investigate the gaseous reduction of nickel oxide with hydrogen; [4][5][6][7][8][9][10][11][12][13] however, there are only a limited number of investigations providing the information on the product structures formed during the reduction process. The detailed investigation of the product microstructure is certainly important, since it is associated with the overall reduction rate and the residual NiO in the final reduction product, as demonstrated in recent publications by Rhamdhani et al [14,15] To ensure continued safe production of nickel using this process, further fundamental studies on the product structures formed during the reduction process need to be carried out.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Nickel Product Structures Developed during the Gaseous Reduction of Solid Nickel Oxide

Hidayat

Rhamdhani

Jak

et al. 2009

Metall Mater Trans B

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The product microstructures developed during the reduction of dense synthetic nickel oxide in H 2 -N 2 and H 2 -H 2 O mixtures between 300°C and 1000°C are reported. A number of distinctly different types of nickel product structures have been identified, namely, coarse fibrous nickel with fissures, fine porous nickel-planar interface, large porous nickel-irregular interface, and dense nickel layer. The influences of gas composition and temperature on the conditions for formation of these microstructures, and their evolution with temperature and time, have been systematically investigated. The condition for formation of the various microstructure types was summarized on morphology maps as functions of reducing gas partial pressure, thermodynamic driving force, and reaction temperature.

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Kinetics of the reduction of nickel oxide by hydrogen

Cited by 70 publications

References 6 publications

Progress in Chemical-Looping Combustion and Reforming technologies

Progress in Chemical-Looping Combustion and Reforming technologies

Kinetics of Reduction of NiO–WO3 Mixtures by Hydrogen

Investigation of Nickel Product Structures Developed during the Gaseous Reduction of Solid Nickel Oxide

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