Investigating the Performance of Amine-Grafted Silica-Base Adsorbents in CO2 Removal from a Natural Gas Stream Using a Diffusion Based Mathematical Model

Abstract:  In this study adiffusion based mathematical model was developed to compare the performance of amine-grafted adsorbents with that of 13X zeolite in a fixed-bed adsorption tower which is used to capture CO2 from both humid and dry nitrogen stream under industrial conditions. The results show that the performance of amine-grafted adsorbent and 13X zeolite is almost the same in the dry conditions. However, amine grafted adsorbents show better outcome when the gas stream is humid. Using amine-grafted adsorbents can reduce the expenses as a result of eliminating the pre-drying unit. Also the results of this simulation indicate that the economical breakthrough time is less than 30 minutes. This breakthrough time indicates that traditional TSA (Thermal Swing Adsorption) processes are uneconomical for regeneration of the adsorbents. Thus, a modified version of TSA process with lower regeneration time, i.e. RTSA (Rapid Thermal Swing Adsorption), must be employed for this case.