An Integrated Model Simultaneously Considering Physical and Chemical Adsorption for CO2 Capture in the Fluidized Bed

As is well known, the fluidized bed adsorption technology is beneficial for reduction of the greenhouse gas emission. Various supported porous sorbents are widely applied for CO₂ capture due to their high specific surface and thermostability, where the adsorption process simultaneously includes physical and chemical adsorption. However, the physical adsorption, a key factor affecting CO₂ capture efficiency, is always neglected in most numerical studies, which consequently leads to distinct deviations between the simulation results and experimental data. Therefore, an integrated model, with simultaneous physical and chemical adsorption into consideration, is proposed in this study to solve the above mentioned problems. Besides, with regard to the particle agglomeration and its effect on the CO₂ capture efficiency, which will decrease gas-solid contact area and thus weaken the heat- and mass-transfer capabilities, EMMS (energy-minimization multi-scale)-based drag model is combined with the integrated adsorption model to study characteristics of CO₂ adsorption process and then the simulation results are validated by experimental data. Meanwhile the effects of inlet gas velocity, initial CO₂ concentration and gas temperature on the adsorption reaction rate and CO₂ capture efficiency are discussed through the thermodynamic analysis. In conclusion, the integrated model simultaneously considering physical and chemical adsorption will provide an effective guidance for numerical study of CO₂ capture in terms of dominate mechanism. Predictably, the proposed model can also be extended to other gas pollutant emissions treatments, such as desulfurization and denitrification.