SHORT CONTACT TIME CATALYTIC PARTIAL OXIDATION OF CH4-H2 MIX OVER Ni FOAMS (original) (raw)

Evaluation of Foam Nickel for the Catalytic Partial Oxidation of Methane

Catalysis Letters, 2009

The catalytic activity of an industrially supplied nickel foam was evaluated for the conversion of methane to syngas via partial oxidation in air. At a temperature of 850°C, 89% CH 4 conversion was attained with H 2 and CO selectivity of 96 and 97%, respectively. The catalytic performance of nickel foam was found to be comparable to an in-house prepared 10%wt Ni/c-Al 2 O 3. Interestingly the foam catalyst was found to be capable of light-off without in situ H 2 reduction unlike the supported nickel catalyst. CH 4 conversion and H 2 and CO selectivity were found to increase as the inlet temperature increased from 650 to 850°C. Increasing the contact time by reducing the gas flow rate resulted in reduced CH 4 conversion and H 2 and CO selectivity, indicating substantial transport limitations. A key finding was that oxidative pretreatment of the nickel foam led to the formation of a surface oxide layer resulting in an increase in surface area and an improvement in catalytic activity.

Synthesis gas production by catalytic partial oxidation of natural gas using ceramic foam catalyst

Catalysis Today, 2017

Partial oxidation (POX) of methane, ethane and propane were studied over mesoporous nanocrystalline Ni/Al 2 O 3 catalysts with high surface area under different feed conditions. Various characterization techniques (XRD, SEM, BET, TPR and TPO) were employed for determining the chemicophysical properties of the prepared catalysts. The effects of active metal (Ni) content on the catalytic performance of the prepared catalysts were investigated and the results showed that 5 wt.% Ni/Al 2 O 3 catalyst possessed the highest catalytic activity in the temperature range of 500e700 C and atmospheric pressure. This catalyst was highly stable (in terms of activity and stability) for 48 h time on stream in methane partial oxidation. However, both the activity and selectivity declined gradually during 12 h time on stream for ethane and propane due to carbon formation. The TPO results revealed that the amount of carbon formed over the spent catalyst decreased by increasing in reaction temperature and O 2 /CH 4 molar ratio from 0.25 to 0.75. Furthermore, the use of higher hydrocarbons (C 2 H 6 , C 3 H 8) in stoichiometric feed ratio increased the carbon deposition on the catalysts.

Catalytic partial oxidation of methane to synthesis gas over Ni/γ-Al 2O 3 catalyst in a fluidized-bed

Applied Catalysis A-general, 2001

The partial oxidation of methane to syngas was studied in this work over Ni-containing ceria catalysts with nickel content of 5, 10 and 20 at.% at atmospheric pressure. All catalysts, in the as prepared state, showed similar activity and CO selectivity at T ≥ 550 • C. Catalyst pre-reduction was not required. Reaction mixtures were dilute, containing 3 mol% CH 4 and 1.5 mol% O 2 . Methane conversion and CO selectivity approached their respective thermodynamic equilibrium values above 550 • C. The H 2 /CO ratio was equal to 2 at T > 600 • C. In the range 0.54-0.04 g s/cm 3 (STP), contact time effects were absent in partial oxidation of methane over the 5 at.% Ni-Ce(La)O x catalyst. The phase composition, nickel dispersion and carbon deposition on the catalysts were investigated by various characterization techniques, including XRD, STEM/EDS, XPS and TPO analyses. The 5 at.% Ni-Ce(La)O x catalyst, comprising highly dispersed nickel oxide in ceria, showed excellent resistance to carbon deposition and stable performance during 100 h-on-stream at 650 • C. On the other hand, high-content (>10 at.%) nickel in ceria, comprising both dispersed nickel and bulk nickel oxide particles, was unstable even after a much shorter time-on-stream; carbon deposition was clearly the cause of this performance instability.

Catalytic Hydrogen Production from Methane Partial Oxidation: Mechanism and Kinetic Study

Chemical Engineering & Technology, 2020

Herein, this mini review investigates the multifunctional potential of a transition and noble metal catalyst supported on either a single support or combined oxide support in the catalytic partial oxidation of methane (CPOM). Also highlighted is the close interaction and interfacial area between the metal, reducible oxide and acidic support, which are crucial for the low-temperature CPOM reaction. The effect of the catalyst component and its preparation methods were considered herein. Their impact on the catalytic performance and stability on the CPOM reaction was evaluated. The two main mechanisms of CPOM; direct partial oxidation (DPO) and the combustion and reforming reaction (CRR) mechanism was also covered along with the most recent kinetic studies. Finally, the deactivation of the CPOM catalysts was studied in term of coke and carbon deposition along with the CO poisoning.

Catalytic partial oxidation of methane over Ni-, Co- and Fe-based catalysts

Catalysis Today, 1998

h i g h l i g h t s Ni and Ru catalysts were tested at low O 2 /CH 4 ratios and in the presence of steam. The metallic surface area of the catalysts influenced the temperature profile. Catalyst deactivation by carbon formation was examined. The ruthenium catalyst did not formed appreciable amounts of carbon.

Hydrogen production from methane through catalytic partial oxidation reactions

Journal of power sources, 2000

This paper reviews recent developments in syn-gas production processes used for partial methane oxidation with and/or without steam. In particular, we examined different process charts (fixed bed, fluidised bed, membrane, etc.), kinds of catalysts (powders, foams, monoliths, etc.) ...

Catalysts for Methane Total Oxidation

2016

Methane, emitted during the incomplete combustion of natural gas vehicles, is an air pollutant that needs to be controlled. In this work, various catalysts were studied for the total oxidation of methane. Pd, Ni and Pd-Ni deposited on a commercial yttria-stabilized zirconia (YSZ) were synthesized by wet impregnation and calcined at 750oC in air and in N2 to study the influence of the calcination treatment. The six samples were characterized by X-ray diffraction. Their catalytic performances were studied for methane oxidation at 500oC along with five perovskites (LaMnO3, LaMn0.98Pd0.02O3, SrTiO3, SrTi0.90Cu0.10O3, SrTi0.95Mn0.05O3). Pd/YSZ and Pd-Ni/YSZ calcined in air and in N2 showed good activity due to the presence of PdO and it was observed that nickel had a positive synergistic effect on the bimetallic catalyst calcined in air. Stability tests at 350oC for 26h were also conducted for these four samples but it was observed that they weren’t very stable in these conditions.