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Numerical simulation of nano-carbon deposition in the thermal decomposition of methane
319 viewed

Numerical simulation of nano-carbon deposition in the thermal decomposition of methane

Homayonifar, P

Numerical simulation of nano-carbon deposition in the thermal decomposition of methane

Homayonifar, P ; Sharif University of Technology | 2008

319 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.ijhydene.2008.09.007
  3. Publisher: 2008
  4. Abstract:
  5. A comparison of various hydrogen production processes indicates that the thermal decomposition of methane (TDM) provides an attractive option from both economical and technical points of view. The main problem for this process is the deposition of the nano-carbon particles on the reactor wall (or catalyst surface). This research concentrates on the numerical simulation of the TDM process without use of a catalyst to find a technique that decreases the carbon accumulation in a tubular reactor. In this model, the produced carbon particles are tracked with the Lagrangian method under thermophoretic, Brownian, van der Waals, Basset, drag, lift, gravity, pressure and virtual mass forces. In additional to experimental studies, numerical simulation also shows some carbon particle deposit around and especially downstream of the reaction zone. The results indicate that the main cause of the separation of particles from the wall is the thermophoretic force, and that downstream of the reactor, where the temperature gradient has decreased, the particles are trapped on the wall under van der Waals and Brownian forces. Two methods are investigated to decrease carbon deposition on the wall. The first is to increase the wall temperature to use the thermophoretic effect, which is rejected because in addition to the increase of thermophoretic force, the probability of particle generation increases nearly 10 times. The second method is the application of a wall jet as a sweeping flow to generate a buffer gas and to decrease particle generation near the wall. This design provides good results in producing a clean reactor. © 2008 International Association for Hydrogen Energy
  6. Keywords:
  7. Catalysis ; Computer simulation ; Decomposition ; Deposition ; Digital signal processing ; Gas fuel manufacture ; Hydrogen ; Hydrogen production ; Jets ; Lagrange multipliers ; Methane ; Photoresists ; Pyrolysis ; Reaction kinetics ; Time division multiplexing ; Van der Waals forces ; Brownian forces ; Buffer gasses ; Carbon accumulations ; Carbon depositions ; Carbon particles ; Catalyst surfaces ; Experimental studies ; Hydrogen production processes ; Lagrangian methods ; Nano-carbon ; Numerical simulations ; Particle generations ; Reaction zones ; Reactor walls ; TDM ; Temperature gradients ; Thermal decompositions ; Thermophoretic ; Thermophoretic effects ; Tubular reactors ; Van der Waals ; Virtual mass forces ; Wall jet ; Wall jets ; Wall temperatures ; Carbon
  8. Source: International Journal of Hydrogen Energy ; Volume 33, Issue 23 , December , 2008 , Pages 7027-7038 ; 03603199 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0360319908011403