INFLUENCE OF THE REACTION TEMPERATURE ON THE OSCILLATORY BEHAVIOR DURING PARTIAL OXIDATION OF METHANE

2008 ◽  
Vol 15 (06) ◽  
pp. 769-774 ◽  
Author(s):  
XIU-BIN REN ◽  
XIANG-YUN GUO
Keyword(s):  
Partial Oxidation ◽  
Reaction Temperature ◽  
Reaction Rate ◽  
Oscillation Period ◽  
Oscillatory Behavior ◽  
Partial Oxidation Of Methane ◽  
Sustained Oscillation ◽  
Oxidation Of Methane ◽  
Langmuir Hinshelwood Mechanism ◽  
Rate Oscillations

The oscillatory behavior during partial oxidation of methane was studied by the Monte Carlo simulation with Langmuir–Hinshelwood mechanism and oxide formation and removal. The well-developed reaction rate oscillations can be observed when the CH 4 adsorption probability varies in a small window. The oscillation window is very sensitive to the variation of reaction temperature. When the temperature increases, the window for sustained oscillation becomes narrow and has an obvious shift. In the meantime, the oscillation period tends to become small and the amplitude decreases. When the temperature increases to a certain value, the oscillations will disappear.

scholarly journals Preparation and Activity of Precipitated Ni-MgO/Al2O3 Catalysts for the Partial Oxidation of Methane

2007 ◽  
Vol 7 (1 & 2) ◽  
pp. 108
Author(s):  
Luis F. Razon ◽  
Carlito M. Salazar ◽  
Hiroo Niiyama ◽  
Long The Nam Doan
Keyword(s):  
Partial Oxidation ◽  
Reaction Temperature ◽  
Flow Reactor ◽  
Fixed Bed ◽  
Catalyst Preparation ◽  
Partial Oxidation Of Methane ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Preparation Methods ◽  
Oxidation Of Methane

The effect of catalyst preparation methods, NiO/MgO molar ratio and reaction temperature on the performance of Ni-MgO catalysts supported on Al2O3 in the partial oxidation of methane to syngas were investigated in a fixed-bed flow reactor. Three catalyst preparation methods (all slight variants of the precipitation method) produced comparable results in CH4 conversion, CO and H2 selectivities. Energy Dispersive X-Ray (EDX) analysis and the color of the catalysts after reaction showed that catalysts produced by simultaneous dissolution of the nickel and magnesium salts may have better carbon deposition resistance. NiO/MgO molar ratio significantly affected the performance of the catalyst. When the NiO/MgO ratio decreased, activity decreased. At a NiO/MgO molar ratio of 1/2 and a reduction temperature of 850°C, CH4 conversion and CO selectivity increased when reaction temperature increased while H2 selectivity remained almost the same. The catalyst gave excellent activity and remained stable after 5h time-on-stream.

Partial oxidation of methane over bimetallic nickel–lanthanide oxides

2010 ◽  
Vol 489 (1) ◽  
pp. 316-323 ◽  
Author(s):  
Ana C. Ferreira ◽  
A.M. Ferraria ◽  
A.M. Botelho do Rego ◽  
António P. Gonçalves ◽  
M. Rosário Correia ◽  
...  
Keyword(s):  
Partial Oxidation ◽  
Partial Oxidation Of Methane ◽  
Lanthanide Oxides ◽  
Oxidation Of Methane

scholarly journals Oscillatory Behaviour of Ni Supported on ZrO2 in the Catalytic Partial Oxidation of Methane as Determined by Activation Procedure

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2495
Author(s):  
Daniela Pietrogiacomi ◽  
Maria Cristina Campa ◽  
Ida Pettiti ◽  
Simonetta Tuti ◽  
Giulia Luccisano ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Partial Oxidation ◽  
Active Sites ◽  
Direct Reduction ◽  
Partial Oxidation Of Methane ◽  
Catalytic Partial Oxidation ◽  
Oxidation Of Methane ◽  
Short Contact Time ◽  
Oxidation Reduction ◽  
Ni Species

Ni/ZrO2 catalysts, active and selective for the catalytic partial oxidation of methane to syngas (CH4-CPO), were prepared by the dry impregnation of zirconium oxyhydroxide (Zhy) or monoclinic ZrO2 (Zm), calcination at 1173 K and activation by different procedures: oxidation-reduction (ox-red) or direct reduction (red). The characterization included XRD, FESEM, in situ FTIR and Raman spectroscopies, TPR, and specific surface area measurements. Catalytic activity experiments were carried out in a flow apparatus with a mixture of CH4:O2 = 2:1 in a short contact time. Compared to Zm, Zhy favoured the formation of smaller NiO particles, implying a higher number of Ni sites strongly interacting with the support. In all the activated Ni/ZrO2 catalysts, the Ni–ZrO2 interaction was strong enough to limit Ni aggregation during the catalytic runs. The catalytic activity depended on the activation procedures; the ox-red treatment yielded very active and stable catalysts, whereas the red treatment yielded catalysts with oscillating activity, ascribed to the formation of Niδ+ carbide-like species. The results suggested that Ni dispersion was not the main factor affecting the activity, and that active sites for CH4-CPO could be Ni species at the boundary of the metal particles in a specific configuration and nuclearity.

Sign in / Sign up

Export Citation Format

Share Document