Effect of Temperature on the Equilibrium Yield of Propylene in Catalytic Processes of Ethanol Conversion

The optimum design, modeling and simulation of a fixed bed multi-tube reformer for the renewable hydrogen production are carried out in the present paper. The analogies between plug flow model and a fixed bed reactor are used as design patterns. The steam reformer is designed to produce enough hydrogen to feed a 200kW fuel cell system (>2.19molH/s) and considering 85% of fuel utilization in the cell electrodes. The reactor prototype is optimized and then analyzed using a multiphysics and axisymmetric model, implemented on FEMLABM(R) where the differential mass balance by convection-diffusion and the energy balance for convection-conduction are solved. The temperature profile is controlled to maximize hydrogen production. The catalyst bed internal profiles and the effect of temperature on ethanol conversion and carbon monoxide production are discussed as well.

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Effect of temperature on ethanol conversion over the surface of Zr-modified zeolite ZSM-5

Catalysis for Sustainable Energy ◽

10.1515/cse-2015-0006 ◽

2016 ◽

Vol 2 (1) ◽

pp. 83-86

Author(s):

Kuzmina Raisa Ivanovna ◽

Pilipenko Anton Yurievich

Keyword(s):

Aromatic Hydrocarbons ◽

Catalytic Properties ◽

Catalyst System ◽

Acid Sites ◽

Effect Of Temperature ◽

Ethanol Conversion ◽

Ethanol Dehydration ◽

Lewis Acid Sites ◽

Increasing Temperature ◽

Catalyst Effect

AbstractIn this paper, we have shown modification of high-silicon zeolite ZSM-5 by zirconium, and the results of ethanol conversion on this catalyst. Effect of process parameters on the selectivity of ethanol dehydration products was analyzed. In addition, a mechanism of aromatic hydrocarbons formation including reactions of dehydrogenation, dehydrocyclization and alkylation of intermediates was discussed. It was found that with increasing temperature a selectivity decreased for reactions of isomerization and increased selectivity for aromatic products and products of cracking reactions. The data also confirms that hexene-1 is an intermediate in the conversion process of ethanol and the catalyst system with 1% Zr-ZSM-5 has a bi-functionality. Catalytic properties of the system in the conversion of hydrocarbons are determined by the presence on their surface of both Broensted and Lewis acid sites.

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Effect of temperature on sucrose to ethanol conversion by Zymomonas mobilis strains

Biotechnology Letters ◽

10.1007/bf00134905 ◽

1980 ◽

Vol 2 (12) ◽

pp. 549-554 ◽

Cited By ~ 24

Author(s):

E. Lyness ◽

H. W. Doelle

Keyword(s):

Zymomonas Mobilis ◽

Effect Of Temperature ◽

Ethanol Conversion

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Alternative Lime Pretreatment of Corn Stover for Second-Generation Bioethanol Production

Agronomy ◽

10.3390/agronomy11010155 ◽

2021 ◽

Vol 11 (1) ◽

pp. 155

Author(s):

Iria Fírvida ◽

Pablo G. del Río ◽

Patricia Gullón ◽

Beatriz Gullón ◽

Gil Garrote ◽

...

Keyword(s):

Corn Stover ◽

Second Generation ◽

Solid Phase ◽

Enzymatic Saccharification ◽

Effect Of Temperature ◽

Ethanol Conversion ◽

Second Generation Bioethanol ◽

Lime Pretreatment ◽

Simultaneous Saccharification ◽

Successful Production

In this work, a delignification process, using lime (Ca(OH)2) as an alternative alkali, was evaluated to improve enzymatic saccharification of corn stover cellulose, with the final goal of obtaining second-generation bioethanol. For that, an experimental design was conducted in order to assay the effect of temperature, lime loading, and time on the corn stover fractionation and enzymatic susceptibility of cellulose. Under conditions evaluated, lime pretreatment was selective for the recovery of cellulose (average of 91%) and xylan (average of 75.3%) in the solid phase. In addition, operating in mild conditions, a delignification up to 40% was also attained. On the other hand, a maximal cellulose-to-glucose conversion (CGCMAX) of 89.5% was achieved using the solid, resulting from the treatment carried out at 90 °C for 5 h and lime loading of 0.4 g of Ca(OH)2/g of corn stover. Finally, under selected conditions of pretreatment, 28.7 g/L (or 3.6% v/v) of bioethanol was produced (corresponding to 72.4% of ethanol conversion) by simultaneous saccharification and fermentation. Hence, the process, based on an alternative alkali proposed in this work, allowed the successful production of biofuel from the important and abundant agro-industrial residue of corn stover.

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Heterogeneous Catalysis in (Bio)Ethanol Conversion to Chemicals and Fuels: Thermodynamics, Catalysis, Reaction Paths, Mechanisms and Product Selectivities

Energies ◽

10.3390/en13143587 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3587 ◽

Cited By ~ 3

Author(s):

Gabriella Garbarino ◽

Giovanni Pampararo ◽

Thanh Khoa Phung ◽

Paola Riani ◽

Guido Busca

Keyword(s):

Heterogeneous Catalysis ◽

Ethanol Conversion ◽

Reaction Paths ◽

Renewable Chemicals ◽

Heterogeneous Catalytic ◽

Heterogeneous Catalytic Processes ◽

Catalytic Processes ◽

Higher Hydrocarbons ◽

Thermodynamic Factors

In gas/solid conditions, different chemicals, such as diethylether, ethylene, butadiene, higher hydrocarbons, acetaldehyde, acetone and hydrogen, can be produced from ethanol with heterogeneous catalytic processes. The focus of this paper is the interplay of different reaction paths, which depend on thermodynamic factors as well as on kinetic factors, thus mainly from catalyst functionalities and reaction temperatures. Strategies for selectivity improvements in heterogeneously catalyzed processes converting (bio)ethanol into renewable chemicals and biofuels are also considered.

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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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