Temperature dependence of interaction parameters in electrolyte NRTL model

Comparative Energetics of Various Membrane Distillation Configurations and Guidelines for Design and Operation

This paper presents a comparative performance study of single-stage desalination processes with major configurations of membrane distillation (MD) modules. MD modules covered in this study are (a) direct contact MD (DCMD), (b) vacuum MD (VMD), (c) sweeping gas MD (SGMD), and (d) air gap MD (AGMD). MD-based desalination processes are simulated with rigorous theoretical MD models supported by molecular thermodynamic property models for the accurate calculation of performance metrics. The performance metrics considered in MD systems are permeate flux and energy efficiency, i.e., gained output ratio (GOR). A general criterion is established to determine the critical length of these four MDs (at fixed width) for the feasible operation of desalination in a wide range of feed salinities. The length of DCMD and VMD is restricted by the feed salinity and permeate flux, respectively, while relatively large AGMD and SGMD are allowed. The sensitivity of GOR flux with respect to permeate conditions is investigated for different MD configurations. AGMD outperforms other configurations in terms of energy efficiency, while VMD reveals the highest permeate production. With larger MD modules, utilization of thermal energy supplied by the hot feed for evaporation is in the order of VMD > AGMD > SGMD > DCMD. Simulation results highlight that energy efficiency of the overall desalination process relies on the efficient recovery of spent for evaporation, suggesting potential improvement in energy efficiency for VMD-based desalination.

Current Trends in Predictive Methods and Electrolyte Equations of State

Over the past 20-30 years, the development of thermodynamic models for electrolyte solutions has experienced remarkable progress. While in the first half of the 20th century, the thermodynamic models were essentially based on the continuum electrostatic approach, nowadays equations of state and predictive methods have been adapted to deal with electrolyte solutions. Given this panorama, in this mini-review, the recent advances in predictive methods and electrolyte equations of state are examined, as well as their performance in predicting activity coefficients and solid-liquid phase equilibrium data. Although this mini-review aims to shed light on the current progress in predictive methods and electrolyte equations of state, it also provides valuable references and information to the several models and theories that form the backbone of the thermodynamics of electrolyte solutions.

The Effects of NaI, KBr, and KI Salts on the Vapor-Liquid Equilibrium of the H2O+CH3OH System

The vapor–liquid equilibrium (VLE) in chemical engineering is indispensable for the design of equilibrium separation processes such as distillation, absorption, extraction, and crystallization. VLE data were measured for H₂O+CH₃OH+NaI, H₂O+CH₃OH+KBr, and H₂O+CH₃OH+KI systems. By analyzing and summarizing the results of H₂O+Methanol+Alkali metal halide systems, the salt effects of NaI, KBr, and KI on the vapor–liquid equilibrium were obtained. Simultaneously, a model based on the NRTL equation (non-random two liquid) was proposed to correlate and calculate the VLE for the systems. In addition, the assumption of solvation based on hydration was introduced in this model. The proposed model can be successfully used to calculate the VLE for H₂O+Methanol+Alkali metal halide systems.