CO₂ Reforming of Methane by Thermal Diffusion Column Reactor with Ni/Carbon-Coated Alumina Tube Pyrogen

Abstract

The CO 2 reforming of methane with a thermal diffusion column (TDC) reactor by using an alumina tube coated with nickel-loaded carbon as the pyrogen, acting as a heated catalyst, was studied. Large surface area of carbon-coat support (400-500 m 2 /g) was obtained by carbonization of a novolak-type phenolic resin. Although the coated carbon showed a minor effect, Ni loading increased the activity of the pyrogen for the reaction. For example, by using 10 wt % Ni-loaded pyrogen at the surface temperature 1260 K, each conversion of methane and carbon dioxide exceeded 65% with upward feeding of 0.44 mmol/min (CO 2 /CH 4 ) 1). The downward feeding of reactant gas showed lower conversions but better stability of the catalytic action of the pyrogen. Performance of TDC reactor for CO 2 reforming of methane can be improved by the better preparation of the pyrogen to increase the activity and with downward feeding to reduce the carbon formation.

CO2 Reforming of CH4 on Ni(111): A Density Functional Theory Calculation

“…On the contrary, the electron transfer from the Ni surface to the 2p orbital of the C atom, which increased its negative charge, strengthens its attraction to the positively charged H, in turn strengthening the C-H bond. This is in agreement with the computed C-H bond shortening of chemisorbed CH-hcp (7) 7). This is consistent with the conclusion, derived from the energetic analyses, that chemisorbed CH-hcp (7) prefers to be oxygenated to CHO-hcp (21), then CHO-hcp dehydrogenates to the main product CO and atomic H.…”

“…For CH, only two stable structures are obtained, CH-hcp (7) and CH-fcc (8). CH interacts with three Ni atoms, and the orientation of C-H is vertical to Ni(111), while the initial structures on the top and bridge sites were optimized into CHhcp (7). On both hcp (7) and fcc (8) sites, CH has a very negative ∆E chem of -6.35 and -6.27 eV, respectively.…”

“…CH interacts with three Ni atoms, and the orientation of C-H is vertical to Ni(111), while the initial structures on the top and bridge sites were optimized into CHhcp (7). On both hcp (7) and fcc (8) sites, CH has a very negative ∆E chem of -6.35 and -6.27 eV, respectively. Two stable structures are obtained for carbon atoms; however, no stable structures are found on the top and bridge sites.…”

Effect of Coexistent Hydrogen on the Selective Production of Ethane by Dehydrogenative Methane Coupling through Dielectric-Barrier Discharge under Ordinary Pressure at an Ambient Temperature

“…The main product of the thermal decomposition of methane (thermal diffusion reactor, 800-1200 ∘ C) is ethene [2][3][4][5][6][7][8] and the polymerized oil [5]. A steep temperature gradient in this reactor was elucidated to give a higher conversion to ethene over the thermodynamic data calculated for the temperature uniform system.…”

“…The dehydrogenative coupling could become one of the green chemistry processes generating no waste materials without use of catalysts. Our previous performances were the synthesis of acetylene from methane (reaction (1)) by the microwave plasma reaction [1] and ethylene from methane (reaction (2)) by the thermal diffusion column [2][3][4][5][6][7][8], both with the acceptable high selectivities of the main product, being the maximum acetylene selectivity of 97.4% with the methane conversion ( CH 4 ) of 92.7% and also the ethylene selectivity of 91.5% with the CH 4 of 9.4%, respectively, 2CH 4 → C 2 H 2 + 3H 2 (1)…”