Analysis of the macrokinetics of CO2 sorption on a 10% NaNO3/MgO sorbent and modeling of an adsorber with a hydrogen productivity of 10 kg/h

Abstract

The work proposed a macrokinetic model of first-order CO2 sorption on a 10 mol.% NaNO3/MgO sorbent. Based on the analysis of experimental gravimetric data, the maximum sorption capacity of the sorbent 10 mol.% NaNO3/MgO was determined, which does not depend on the partial pressure of CO2 and at 320 °C is 159% (based on the initial mass of the sample), or 13.4 mmol CO2/ gsorb. The calculated value of the sorption constant kads at temperatures of 280-320 °C and a partial pressure of CO2 of 0.50-0.75 atm is 0.017 min-1 atm-1. Based on the obtained kinetics, a simulation of an adiabatic and isothermal CO2 adsorber was made within the framework of a technological scheme for producing hydrogen 10 kg/h from natural gas at an operating pressure of 12 atm. During the calculations, it was shown that for the effective functioning of the adsorber, intensive removal of the heat released during the sorption process is necessary. This allows CO2 sorption to be carried out for 30 minutes at a temperature of 300 °C and a volumetric flow rate GHSV = 1170 h-1, while the concentration of CO2 at the outlet in dry gas does not exceed 1.5 mol.%.