Analysis of the Macrokinetics of CO2 Sorption on 10%NaNO3/MgO Sorbent and Modeling of an Adsorber with a Hydrogen Capacity of 10 kg/h

This study proposes a first-order macrokinetic model for CO₂ sorption on a 10 mol % NaNO₃/MgO sorbent. According to the experimental gravimetric data, the maximum sorption capacity of the 10 mol % NaNO₃/MgO sorbent is determined and does not depend on the partial pressure of CO₂; at 320°C it is equal to 159% (based on the initial mass of the sample) or 13.4 mmol CO₂/g_sorb. The calculated value of the sorption constant k_ads at temperatures of 280–320°C and a CO₂ partial pressure of 0.50–0.75 atm is 0.017 min^–1 atm^–1. Based on the obtained kinetics, modeling of adiabatic and isothermal CO₂ adsorbers was performed within the framework of the technological scheme for producing 10 kg/h of hydrogen from natural gas at an operating pressure of 12 atm. The calculations showed that for the adsorber to function effectively intensive removal of the heat released during the sorption process is necessary. This allows for the sorption of CO₂ for 30 min at a temperature of 300°C and a gas hourly space velocity GHSV = 1170 h^–1, while the concentration of CO₂ at the outlet in dry gas does not exceed 1.5 mol %.