Investigation of CO2 and CH4 capture from syngas in adsorption process and breakthrough modeling by modified Lattice-Boltzmann mesoscale method

Abstract

A modified Lattice Boltzmann method (LBM) was developed to model and analyze the transient flow and multi-component adsorption in a dispersive packed bed column of activated carbon as a new kind of meso-scale modeling. The model using D2Q9 (two dimensions and 9 speed) lattice solves the two-dimensional space, convection-dispersion adsorption model for the CO2–CH4 mixture in rich H2 at transient condition. The sink/source term model was considered as the adsorption/desorption kinetic rate based on Extended Langmuir theory for multicomponent mixture. The mole balances in the solid phase were considered as the lumped kinetic model of adsorption-desorption reaction. The results of the developed model was presented as the flow velocity and molar fractions of the components in axial and radial directions of the bed as well as breakthrough curves of CO2 and CH4 from their mixture in H2 gas stream under pressures of 3 and 5 bar and inlet linear velocities of 0.01, 0.04, 0.08 and 0.1m/min. The breakthrough curves were validated with the experimental data and the average absolute relative deviations (AARD) were calculated for both components. In addition, the results of LBM were compared with finite difference method in which AARDs were dtermined as 3% and 8% for CO2,4% and 7% for CH4 , by LBM and FDM, respectively.