CO2 adsorption efficiency and rate of CO2 adsorption

https://doi.org/10.1093/ce/zkac020

“The CO₂ adsorption efficiency of the adsorbent was presented as an adsorption capacity (Q_ads) that was determined by plotting between C_ou/C_in versus time to obtain a breakthrough profile. The Q_ads could be calculated using Equations (5) and (6) [68, 70]:”

“where Q_ads is the adsorption capacity (molCO₂/g), F is the total flow rate (mol/minute), C_in is the concentration of CO₂ entering the reactor (vol%), C_ou is the concentration of CO₂ downstream of the reactor (vol%) and t is the time at which the C_ou reaches its maximum level (minutes). M is the weight of the adsorbent (g) and t_st is the stoichiometric time corresponding to the CO₂ stoichiometric adsorption capacity (minutes). The stoichiometric adsorption capacity can be shown to be proportional to the area between the breakthrough curve and a line at C_ou/C_in = 1.0.”

“The rate of CO₂ adsorption was also determined by observing the slope of the plot of Q_ads with respect to time. The regeneration performance of the adsorbents could be determined by comparing the Q_ads of the first and the second adsorption runs of the same adsorbent. The energy requirement for adsorbent regeneration (Q_reg, kJ/molCO₂) was calculated using Equation (7), which was reported in the previous work [68] and adopted from the work of Singto et al. [71]:”

“where K is the thermal conductivity of the stainless-steel reactor (16.5 W/mK), A is the surface area of the cylindrical sector of the adsorbent in the reactor (m²), Δt is the temperature difference between inside and outside the reactor (K) and Δx is the thickness of the reactor (m). The CO₂ produced (mmolCO₂/g.s) is obtained from the CO₂ adsorption capacity of the second run of the CO₂ adsorption experiment.”