A novel integrated thermal-/membrane-based solar energy-driven hybrid desalination system: Concept description and simulation results

A comparison of vacuum and direct contact membrane distillation for phosphorus and ammonia recovery from wastewater

Several desalination systems with distinct operational principles have been developed to enhance the generation of freshwater and optimize system efficiency. Adsorption desalination (AD) systems are highly desirable because to their ability to simultaneously achieve desalination and cooling using minimal energy input. These systems offer significant cost savings in terms of maintenance compared to conventional desalination systems. In order to gain a comprehensive understanding of the fundamental constituents of this desalination technology, the present study initially expounds upon the theory of adsorption and the process of circulation. Aims: The aim of this study is to conduct a thorough analysis of adsorbents for adsorption desalination and adsorption desalination technologies, and investigation into their potential integration with established conventional cycles, including multiple-effect distillation (MED), solar regenerable, and integrated evaporator-condenser cycles. Methodology and results: The findings of this study involve the evaluation and summarization of pertinent research on the fundamental aspects of the adsorption desalination system. These aspects include the thermodynamic process and cycle, performance assessment, adsorbents, and adsorption desalination technologies. The location, heat energy supply, collector, evaporator, condenser, adsorption desalination, adsorbent materials, and findings are investigated. Conclusion, significance and impact study: The discourse pertaining to prospective avenues of research, which will prove beneficial for analogous investigations within this domain, reaches a culmination.

Numerical simulations were carried out to assess the technical and economic feasibility of a solar water desalination system that has a novel hybrid Concentrating Photovoltaic Thermal (CPVT) collector coupled with a Vacuum Membrane Distillation (VMD) process. A special characteristic of this CPVT is its triangular receiver with PV cells facing the reflecting surface. This type of receiver has the advantage of generating more electricity with less PV surface area and great potential to be used to hybridize conventional parabolic thermal collectors. TRNSYS was employed to analyze the annual performance of the CPVT-VMD system evaluating parameters such as solar fraction, specific permeate production and specific energy production for different coastal cities. In the dynamic simulations, local annual weather data and specific information about the characteristics and operating conditions of a real CPVT collector and a VMD module were considered. From the parametric analysis the optimal surface area of collectors and the input temperature of the VDM module were determined. A maximum specific permeate of 218.410 m 3/m2VMD for Acapulco, MX, and a minimum of 170.365 m 3/m2VMD for Singapore, SG, were achieved for the proposed CPVT-VMD system of four solar collectors with an operating set temperature of 55 °C. An economic profit was found after 7 years for Acapulco city, which showed great potential to use solar energy from hybrid CPVT collectors for a VMD process to provide freshwater in coastal cities.

Optimum exergoeconomic modeling of novel hybrid desalination system (MEDAD+RO)

Effect of seawater-coolant feed arrangement in a waste heat driven multi-stage vacuum membrane distillation system

Pilot studies on synergetic impacts of energy utilization in hybrid desalination system: Multi-effect distillation and adsorption cycle (MED-AD)

Vacuum membrane distillation (VMD) is a compelling technique for desalinating water because it exhibits superior pure water permeability at lower operating temperatures compared to other membrane distillation technologies. This leads to reduced energy consumption, lower heat loss via conduction across the membrane surface, and minimal heat transfer through conduction due to the low pressure on the permeate side. Detailed modelling of heat and mass transfer in VMD is essential for optimizing the process as it provides valuable insights that contribute to the advancement and successful implementation of seawater desalination using VMD technology. The aim of this study is to establish a comprehensive numerical model that describes the water vapor transfer across a hydrophobic micro-porous membrane in single-stage and multi-stage VMD processes for seawater desalination. The numerical predictions were compared to experimental data in addition to numerical computations based on an existing literature database, and good agreement has been found. The investigation also conducted a sensitivity analysis of process variables and membrane specifications on the VMD performance, as well as an assessment of the impact of temperature and concentration polarization. The obtained results showed that the permeation flux reached 18.42 kg/m2·h at 35 g/L feed concentration, 65 °C feed temperature, 50 L/h feed flow rate, and 3 kPa vacuum pressure. Moreover, the findings revealed that the feed temperature was the most significant factor, while the feed flow rate was the least important in determining the permeation flux. Additionally, the findings suggested that the effectiveness of the VMD process heavily relies on the composition and permeability of the support materials. Finally, the results confirmed that temperature polarization had a more significant effect on the reduction of the permeate flux than the concentration polarization.

Recycling brine water of reverse osmosis desalination employing adsorption desalination: A theoretical simulation

Performance investigations of hybrid adsorption and thermo electric dehumidification desalination system

Experimental analysis on hybrid adsorption and open air cycle humidification dehumidification (AD–OHD) desalination system

The use of VMD data/model to test different thermodynamic models for vapour–liquid equilibrium

Solar powered hybrid desalination system using a novel evaporative humidification tower: Experimental investigation

Life cycle assessment for algae-based desalination system

An integrated membrane distillation (MD) flowsheet, consisting of direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) units, was proposed and analysed in terms of thermal performance and water recovery factor, for the first time. The same lab-scale membrane module (40 cm2) was used for carrying out experiments of DCMD and VMD at fixed feed operating conditions (deionised water at 230 L/h and ~40 °C) while working at the permeate side with deionised water at 18 °C and with a vacuum of 20 mbar for the DCMD and the VMD configuration, respectively. Based on experimental data obtained on the single modules, calculations of the permeate production, the specific thermal energy consumption (STEC) and the gained output ratio (GOR) were carried out for both single and integrated units. Moreover, the calculations were also made for a flow sheet consisting of two DCMD units in series, representing the “traditional” way in which more units of the same MD configuration are combined to enhance the water recovery factor. A significant improvement of the thermal performance (lower STEC and higher GOR) was obtained with the integrated DCMD–VMD flowsheet with respect to the DCMD units operating in series. The integration of DCMD with VMD also led to a higher permeate production and productivity/size (PS) ratio, a metric defined to compare plants in terms of the process intensification strategy.

The rapid development of nuclear power plants (NPPs) in China has caused increasing attention to be paid to the treatment of low-level radioactive wastewaters (LLRWs). One possibility is the application of vacuum membrane distillation (VMD). In this study, a commercial hydrophobic microporous polypropylene membrane was investigated with respect to nuclide decontamination and permeate flux performance in the VMD process. The results demonstrate that vacuum pressure has the most obvious influence on permeate flux, followed by feed temperature and feed velocity. Despite the influence of operational parameters, effective nuclide filtering can be achieved with average decontamination factor (DF) values consistently higher than 1700. The salt concentration in the feed solution decreases the permeate flux and nuclide filtering. However, the VMD process still offers high average DF values of 6000 for Cs(I), 3700 for Sr(II), and 8300 for Co(II), even when the feed salt concentration reaches 80 g L−1. After operation at a high salt concentration, there is no obvious variation in the chemical composition on the membrane surface based on the attenuated total reflectance–Fourier transform infrared spectra. A brief comparison shows that the process integrating reverse osmosis and VMD is a promising method for treating LLRWs and minimizing radioactive waste in NPPs.