CO2 Capture Using Aqueous Potassium Carbonate Promoted by Ethylaminoethanol: A Kinetic Study

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• 作者：Rahul R. Bhosale ; Anand Kumar ; Fares AlMomani ; Ujjal Ghosh ; Ahmed AlNouss ; Jonathan Scheffe ; Ram B. Gupta
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：May 11, 2016
• 年：2016
• 卷：55
• 期：18
• 页码：5238-5246
• 全文大小：451K
• 年卷期：0
• ISSN：1520-5045

文摘

Kinetics of absorption of CO₂ in an aqueous potassium carbonate (K₂CO₃) promoted by ethylaminoethanol (EAE) solution (hereafter termed as APCE solvent) was investigated in a glass stirred cell reactor by employing a fall in pressure technique. The reaction chemistry associated with the CO₂–APCE solvent system was described by the zwitterion mechanism. The solubility and diffusivity of CO₂ in the APCE solvent were experimentally determined at different experimental conditions. Furthermore, the effect of the initial EAE concentration (0.6–2 kmol/m³) and reaction temperature (303–318 K) on the rate of absorption of CO₂ was studied in detail. The experimental findings show that with the increase in the EAE concentration and reaction temperature, the rate of CO₂ absorption in the APCE solvent also increases considerably. Kinetic measurements further confirm that the absorption of CO₂ in the APCE solvent belongs to the fast reaction regime with first-order kinetics with respect to EAE and first-order kinetics with respect to CO₂. Due to the addition of EAE as a promoter in an aqueous K₂CO₃, significant improvement in the rate of absorption of CO₂ was realized. The rate constant (k₂) for the CO₂–APCE solvent system was observed to be higher as compared to monoethanolamine (MEA) promoted aqueous K₂CO₃. For instance, k₂ for the absorption of CO₂ in the APCE solvent was observed to be equal to 45540 m³/kmol·s at 318 K. Furthermore, the activation energy for the CO₂–APCE solvent system was estimated to be 81.7 kJ/mol. The lumped parameter, , where H_CO2 is solubility of CO₂ and D_CO2 is diffusivity of CO₂ in the APCE solvent, was calculated based on the kinetic measurements and observed to be equal to 1.2 × 10^–6 kmol^1/2/m^1/2·s·kPa.