Active and stable Ni based catalysts and processes for biogas upgrading: The effect of temperature and initial methane concentration on CO2 methanation

One of the most important tools for mitigating climate change is biogas production. Increasing their use requires improving the energy value of biogas by reducing its carbon dioxide content while increasing the methane concentration in biogas. Biological purification of biogas using microalgae strains − merging biogas upgrading method where microalgae use carbon dioxide for their growth during the process of photosynthesis. A four-column photobioreactor was constructed with Monoraphidium Griffithi, Chlorella sp. microalgae strains, distilled water and MWH medium for purification of biogas. Experimental studies determined sizes, shapes and of microalgae cells, the pH changes of mediums used after biogas treatment and the composition of biogas before and after upgrading using photobioabsorber. Microalgae Monoraphidium Griffithi was estimated to have the greatest contribution to CO2 reduction by decreasing from 31.0% to 10.0%. The smallest reduction in CO2 was recorded when biogas was flowing through MWH medium. Experiments have shown that the absorption of biogas components results in the release of oxygen. As the biogas was flowing through all suspensions, the oxygen concentration increased from 3.6 to 5.2%.

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CO2 methanation in the presence of methane: Catalysts design and effect of methane concentration in the reaction mixture

Journal of the Energy Institute ◽

10.1016/j.joei.2019.01.015 ◽

2020 ◽

Vol 93 (1) ◽

pp. 415-424 ◽

Cited By ~ 16

Author(s):

L. Pastor-Pérez ◽

V. Patel ◽

E. Le Saché ◽

T.R. Reina

Keyword(s):

Methane Concentration ◽

Co2 Methanation

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Nucleation of Disorder in Fe3Al Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061574 ◽

1967 ◽

Vol 25 ◽

pp. 312-313

Author(s):

P. R. Swann ◽

W. R. Duff ◽

R. M. Fisher

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Annealing Temperature ◽

Antiphase Domain ◽

Effect Of Temperature ◽

Domain Structures ◽

Transmission Electron ◽

Domain Boundaries ◽

Higher Temperature ◽

The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

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The effect of temperature on high-resolution TEM image contrast

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139573 ◽

1995 ◽

Vol 53 ◽

pp. 640-641

Author(s):

T. Geipel ◽

W. Mader ◽

P. Pirouz

Keyword(s):

Form Factor ◽

Inelastic Scattering ◽

Accurate Method ◽

Waller Factor ◽

Effect Of Temperature ◽

Specimen Thickness ◽

Influence Of Temperature ◽

Debye Waller Factor ◽

Influence Of Temperature On ◽

Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

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