Analysis of Biphasic Cracking of Methane for Hydrogen Production Using Solar Energy

Hydrogen can be produced by many processes, by a series of chemical reactions many of which have been known for centuries. However, most of these reactions raise severe environmental and safety problems, while availability of raw materials is a critical problem. One of the partial solutions is solar hydrogen. It appears that cracking of carbon-rich materials is the right solution for this energy. In this context comes this numerical simulation of the methane cracking phenomenon. In the simulation, we have taken in to account the existence of carbon as a homogeneous powder. The mixture is considered to be biphasic formed by a gaseous phase with methane, hydrogen gases and carbon black powder solid phase. This powder is formed by solid particles with same diameter (d=50nm). The cracking phenomenon of the methane into hydrogen and carbon black takes place in a cylindrical cavity of 16 cm in diameter and 40 cm in length under the heat of concentrated solar radiation without any catalyst. A commercial calculation code "ANSYS FLUENT" is used to simulate the cracking phenomena. Two cases were studied: the first one applying a maximum solar radiation of 16MW/m2 on the side wall of the reactor and the second one a maximum solar radiation of 5 MW/m2. The CH4 flow rate used at the inlet of the reactor is 0.4 L/min and the low Reynolds K - ε turbulence model was applied. A time step of 0.04s has been used.The cracking rate exceeds 90% with a maximum solar radiation of 16MW/m2 and this rate does not reach 85% with a maximum solar radiation of 5MW/m2.The dimensions of the cavity are important and it allows going from the experimental scale to the industrial scale. Working without any catalyst facilitates the separation of the elements after cracking.

Analysis of Biphasic Cracking of Methane for Hydrogen Production Using Solar Energy

Hydrogen can be produced by many processes, by a series of chemical reactions many of which have been known for centuries. However, most of these reactions raise severe environmental and safety problems, while availability of raw materials is a critical problem. One of the partial solutions is solar hydrogen. It appears that cracking of carbon-rich materials is the right solution for this energy. In this context comes this numerical simulation of the methane cracking phenomenon. In the simulation, we have taken in to account the existence of carbon as a homogeneous powder. The mixture is considered to be biphasic formed by a gaseous phase with methane, hydrogen gases and carbon black powder solid phase. This powder is formed by solid particles with same diameter (d=50nm). The cracking phenomenon of the methane into hydrogen and carbon black takes place in a cylindrical cavity of 16 cm in diameter and 40 cm in length under the heat of concentrated solar radiation without any catalyst. A commercial calculation code "ANSYS FLUENT" is used to simulate the cracking phenomena. Two cases were studied: the first one applying a maximum solar radiation of 16MW/m2 on the side wall of the reactor and the second one a maximum solar radiation of 5 MW/m2. The CH4 flow rate used at the inlet of the reactor is 0.4 L/min and the low Reynolds K - ε turbulence model was applied. A time step of 0.04s has been used.The cracking rate exceeds 90% with a maximum solar radiation of 16MW/m2 and this rate does not reach 85% with a maximum solar radiation of 5MW/m2.The dimensions of the cavity are important and it allows going from the experimental scale to the industrial scale. Working without any catalyst facilitates the separation of the elements after cracking.

___

  • [1] Grimes C. A., Varghese O. K. and Ranjan S., “Light, Water, Hydrogen, the solar generation of hydrogen by water photoelectrolysis”, Springer Science + Business Media, LLC, (2008).
  • [2] Kodama T., “High-temperature solar chemistry for converting solar heat to chemical fuels”, Progress in energy and combustion science, 29:567–597, (2003).
  • [3] Etiévant C., “Solar high–temperature direct water splitting- a review experiments in France”, Solar Energy Material, 24:413–440, (1991).
  • [4] Sakurai M., Bilgen E., Tutsumi A. and Yoshida K., “Solar UT-3 thermo chemical cycle for hydrogen production”, Solar Energy, 57:51–58, (1996).
  • [5] Abanades S. and Flamant G., “Thermo chemical hydrogen production from a two step solar- driven water-splitting cycle based on cerium oxides”, Solar Energy, 80:1611–1623, (2006).
  • [6] Kodama T., Kondoh Y., Yamamoto R., Andou H. And , Satou N., “Thermochemical - hydrogen production by a redox system of ZrO2 supported- Co(II)-Ferrite”, Solar Energy, 78:623–631, (2005).
  • [7] Steinfeld A., Sanders S., and Palumbo R., “Design aspects of solar thermo chemical engineering- a case study: Two- step Water – Splitting cycle using the Fe3O4/FeO”, Solar Energy, 65:43–53, (1999).
  • [8] Chavin P., Abanades S., Flamant G. and Lemort F.,“Two-step water splitting thermochemical cycle based on iron oxide redox pair for solar hydrogen production”, Energy, 32:1124–1133, (2007).
  • [9] Vishnevetsky, M. E., “Production of hydrogen from solar zinc steam atmosphere”, International Journal of Hydrogen Energy, 32:2791–2802, (2007).
  • [10] Kaneko H., Miura T., Ihihara H., Taku S., Ykoyama T., Nakajima H. and Tamaura Y., “Reactive ceramics of CeO2-MOx(M= Mn, Fe, Ni, Cu) for H2 generation by two-step water splitting using concentrated solar thermal energy”, Energy, 32:656–663, (2007).
  • [11] Hernandez E. D., Olalde G., Bonnier G., Le Frious F. and M. Sadli, “Avaluation of the application of a solar furnace to study the suitability of metal oxides to be used as secondary reference points in the range 2000–3000°C”, Measurement, 34:101–109, (2003) .
  • [12] Y. Benguerba, L. Dehimi, M. Virginie, C. Dumas, “Modelling of methane dry reforming over Ni/Al2O3 catalyst in a fixed-bed catalytic reactor”, Journal of Reaction Kinetics, Mechanisms and Catalysis, 114:109–119, (2015).
  • [13] Roohi P., Alizadeh R. and Fatehifar E., “Thermodynamic Study of Transformation of Methane to Synthesis Gas Over Metal Oxides”, International Journal of Thermophysics, 36:88–103, (2015).
  • [14] Abanades S. and Flamant G., “Hydrogen production from solar thermal dissociation of methane in a high- temperature fluid wall chemical reactor”, Chemical engineering and processing: Process Intensification, 47:490–498, (2008).
  • [15] Flamant G., “Production d’hydrogène par énergie solaire –Programme énergie CNRS- MRNT - DGA – Rapport final du projet intégré HYSOL. (2002-2004). http://www.gedeon.prd.fr/ATELIERS/27_28_11_2003/presentations/H2-SolaireIMP-CNRS%20flamant.pdf.
  • [16] Hirsch D., and Steinfeld A., “Solar hydrogen production by thermal decomposition of natural gas using a vortex-flow reactor”, International Journal of Hydrogen Energy, 29:47–55, (2004).
  • [17] De Falco M., Marrelli L. and Iaquaniello G,. “Membrane Reactors for Hydrogen Production Processes - Springer-Verlag, London Limited, (2011).
  • [18] Liu K., Song C and Subramani V., “Hydrogen and syngas production and purification technologies”, John Wiley & Sons, Inc, Hoboken, New Jersey, (2010).
  • [19] Turner J., Sverdrup G., Mann M.K., Maness P.C., Kroposki B., Ghirardi M., Evans R. and Blake D., “Renewable hydrogen production”, International Journal of Energy research, 32:397–407, (2008).