VLE Modeling of Aqueous Solutions of Unloaded and Loaded Hydroxides of Lithium, Sodium and Potassium

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• 作者：Shahla Gondal ; Muhammad Usman ; Juliana G.M.S. Monteiro ; Hallvard F. Svendsen ; Hanna Knuutila ; ^{hanna.knuutila@ntnu.no" class="auth_mail" title="E-mail the corresponding author}
• 关键词：VLE ; Apparent Henry's law constant ; Hydroxides and carbonates ; Lithium ; Sodium and Potassium
• 刊名：Energy Procedia
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：86
• 期：Complete
• 页码：282-293
• 全文大小：515 K

文摘

This work focuses on equilibrium modeling of CO₂ solubility in aqueous solutions of unloaded (as hydroxides) and loaded (as carbonates) hydroxides containing Li⁺, Na⁺ and K⁺ counter ions. Due to the ionic nature of the LiOH/NaOH/KOH-CO₂-H₂O solutions, the electrolyte-Non-Random-Two-Liquid (e-NRTL) model, described by Chen and Evans [1], is applied to correct the non-idealities in the liquid phase. The special feature of the equilibrium model employed in this work is the simultaneously regression of Vapor-Liquid Equilibrium (P_CO2, P_total) and apparent Henry's law constant data selected from literature and P_total data for LiOH measured in this work. This approach will give better prediction for the molecular CO₂ activity coefficients and the liquid phase activities calculated by use of the resulting e-NRTL model will be consistent with the apparent Henry's law constant. The equilibrium model developed in this work is based on and represented 112 data points for Li⁺ with 2.7% total AARD, 432 selected data points for Na⁺ with total 7.2% AARD and 354 selected data points for K⁺ with total 9.9% AARD. The total pressure data over aqueous LiOH solutions were measured for a range of concentrations (0.25 – 8.5 wt. %) and temperatures (40 – 90 °C) using an ebulliometer.