| Summary: | 碩士 === 國立中興大學 === 環境工程學系所 === 98 === This study presents an approach to study kinetics of CO2 adsorption on low-temperature dry sorbents. A numerical model that considers mass transfer of CO2 in the gas phase and simultaneous adsorption and desorption of CO2 in the solid phase was developed to predict system performance of a fixed-bed CO2 adsorber packed with CNTs, CNT(APTS), MSP, MSP(EDA), Y60, and Y60(EDA). The model provide reaction rate constants of adsorption and desorption, which were employed to obtain activation energies and heat of adsorption.
The results of model showed that the present model could well describe measured breakthrough curves of CO2 adsorption under different influent CO2 concentrations and temperatures.
All sorbents show the rate constant of adsorption and desorption that are increased with temperature. The heat of adsorption for CNTs and CNT(APTS) reflected that an exothermic nature. MSP and MSP(EDA) at 20-60℃ reflected endothermic nature. Y60 and Y60(EDA) at 20-80℃ reflected endothermic nature. MSP, MSP(EDA), Y60, and Y60(EDA) reflected exothermic nature at other temperature. The adsorption process for all sorbents are physical sorption that is main principle.
Because there are amine groups on modified-sorbents that can increase interaction with CO2, the activation energy and adsorption heat of modified-sorbents is greater than raw sorbents .
The key model parameters of CO2 adsorption on sorbents that are CNT(APTS), MSP(EDA), and Y60(EDA) were evaluated in a sensitivity analysis to see their respective effects. A decrease in gas flow rate (Q) as well as an increase in maximum adsorption capacity (qm) and equilibrium adsorption constant (b) remarkably caused a rise in breakthrough time and thus resulted in a high adsorption capacity of CO2. The result show equilibrium adsorption constant is most effect for modeling.
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