Computational Study on Heat Transfer and Fluid Flow Aspects of Adsorption-Based CO2 Capture

This work investigates the effects of reactor aspect ratio, gas inlet temperature, particle size of the adsorbent, gas inflow rate on the adsorption capacity and breakthrough curve for the adsorbent-CO2 pair useful for CO2 capture applications. For this purpose, a fixed-bed cylindrical reactor filled with Mg-MOF-74 as an adsorbent is employed and CO2 gas is allowed to pass through the porous bed axially. Adsorption uptake of the bed is higher at lower gas inlet temperature and the rate of uptake is faster for high aspect ratio geometries. However, the associated bed pressure drop is also high for high aspect ratio. As the mass flow rate of feed gas increases its uptake decreases also, no considerable effect of particle size is observed on the adsorption uptake. Considering the effect on the breakthrough curve, it reaches unity faster for high aspect ratio geometry which signifies faster saturation of the adsorbent bed. The same is attained when gas inlet temperatures are high and the curve attains unity faster than lower inlet temperature beds. For all the computational purposes, COMSOL multiphysics software is used.