Papers by Keyword: Methane Decomposition

Abstract: The thermo-catalytic decomposition (TCD) of methane has attracted the attention of numerous researchers’ around the world as an ideal approach for hydrogen production, which in turns, can be used as an appropriate feeding gas in fuel cells operating at low temperatures. The TCD of methane is capable to produce a valuable by–product, pure carbon, which can excessively alleviate the total cost of the process. In this study, we report TCD of methane over 30% Ni supported Y zeolite catalyst at 550 and 600 °C was conducted in a fixed bed reactor and the yield of hydrogen from the reactor was analyzed by GC. As can be observed that, the TCD of methane over Ni-supported Y zeolite showed maximum conversion (31 and 15.90 % at 600 and 550 °C, respectively) at the initial stages and on stream of reaction time, it decreased gradually; and ultimately, deactivated the catalyst completely. The cause for this is the formation of encapsulating carbon on Ni active sites which deactivates the catalyst over the course of reaction time. Hydrogen production rate, carbon accumulation (CA) and carbon formation rate (CFR) were investigated at three representative times for both temperatures. The CFR analysis showed that the growth of filamentous carbon was steady-state at the first stage and then reduced to a relic activity and it remains constant during the rest of the reaction. The descriptive dissemination of methane TCD over Ni-supported Y zeolite has been speculated in this paper.

Abstract: The microwave-assisted CH₄ decomposition over a pyrolysis residue of sewage sludge (PRSS), which acted as a microwave receptor and a low-cost catalyst without further activation, was investigated in a multimode microwave reactor. The results indicated that the microwave heating of PRSS is heavily influenced by atmosphere. The PRSS temperature in CH₄, N₂ and H₂ atmosphere follow the sequence of T_CH4 < T_H2 <T_N2. PRSS shows excellent initial activity for methane decomposition, but it deactivated very quickly. It was inferred that the fast deactivation of PRSS was mainly caused by temperature falling in CH₄ atmosphere.

Abstract: The influence of morphology of the support particles upon the nickel-catalyzed decomposition of methane into carbon nanotubes and hydrogen was explored using a thermogravimetric apparatus. High carbon nanotube yield was attained by the Ni catalysts supported on the glycothermally synthesized ZrO2 and Er3Ga5O12 particles, which had spherical shapes. Quite high carbon yield was also obtained by the Ni catalyst supported on spherical Al2O3 particles (Nanophase Tech. Corp.). It was concluded that the most important factor governing the carbon yield is the morphology of the catalyst support, which contributes to the internal pressure of carbon nanotubes thus determining their chemical potentials.

Abstract: Catalytic decomposition of methane is an environmentally attractive approach to CO2-free hydrogen production. The decomposition of methane over carbon nanofibers was carried out in a fixed bed flow reactor. The objectives of this study are to demonstrate the activity of carbon nanofibers for methane decomposition in comparison with that of carbon black and to investigate the nature of active sites in the carbon catalysts. The catalytic activities of different carbon catalysts were found in the following order: carbon nanofiber > HI-900L carbon black > N330 carbon black > non-catalyst. After investigating the surface area and mass of the carbon catalysts after methane decomposition, the nature of active sites was discused.