Synthetic natural gas that is CO2-free can be produced from biogas via the methanation reaction (CO+3H2->CH4+H2O). For this purpose, gas/solid fluidized beds (FBs) carry out the methanation reaction using catalytic Ni/Al2O2 particles as the condensed phase. In the ongoing PhD project, reactions on the surface and in the interior of such catalytic particles will be simulated. As the internal particle porosity amounts to 25% of the FB volume at rest, a key issue is to assess its impact on the FB performance and to train macroscopic 1-D models for the entire FB with a porosity-induced enhanced axial dispersion.
Lattice Boltzmann method (LBM) has shown its applicability and accuracy in many problems, especially multi-phase and multi-component flows and complex geometries. One of its feature is parallelization potential which can give noticeable speedup in numerical simulations. Hence, a high performance hybrid MPI-CUDA code is developing to study the dynamics of porous particles in fluidized bed for biogas methanation. We first introduce the methodology how to calculate thermodynamic and transport properties of mixture, and then benchmark the code for the reactive boundary model. For benchmarking oxidation of methane is considered and the results are compared with that of classical computational fluid dynamics (CFD). Finally, we evaluate the current model for methanation and realistic complex particle geometries (obtained from X-ray tomography at SLS) for future studies.
LSM