Simultaneous Production Of Fresh Water Research Articles

Super Moisture-Sorbent Sponge for Sustainable Atmospheric Water Harvesting and Power Generation.

Sorption-based atmospheric water harvesting (SAWH) shows great promise to mitigate the worldwide water scarcity, especially in the arid regions. Salt-based composite materials are the extensively used sorbents for SAWH, however, they suffer from complex preparation to avoid salt leakage. Furthermore, the significant amount of heat produced during water harvesting process is often neglected and wasted. Herein, an integrated strategy is developed to synthesis salt-based stable super moisture-sorbent sponge by using the chelation of LiCl and dopamine (DA), and the simultaneous polymerization of DA on melamine sponge (PMS). The as-prepared LiCl/PMS/CNTs showed high water uptake, reaching 1.26 and 1.81g g-1 at 15% and 30% RH, respectively, and no salt leakage is observed during the water absorption process. Remarkable daily water production of 3.47kg kg-1 day-1 in an arid environment (30% RH) is achieved. Moreover, a dual-function system is successfully constructed by combining the LiCl/PMS/CNTs with a thermoelectric module to fully utilize the heat generated from the SAWH process, which can realize the simultaneous production of fresh water and electricity. The maximum output power density is up to 35.4 and 454.4mW m-2 during the water absorption and desorption process, respectively.

Permeate gap thermo-osmotic system for simultaneous freshwater production, energy storage, and power generation

The emerging thermo-osmotic system enables harvesting low-grade thermal energy below 100 °C for the simultaneous production of fresh water and electricity. Considering the fluctuation of low-grade heat sources, a novel permeate gap thermo-osmotic system without pump pressurization was proposed in this study, which also allows for energy storage. A lab-scale setup with a 32 cm2 membrane area was built, by which a 2 W light bulb was successfully illuminated through the thermal energy-potential energy-electricity conversion process. In the pressurization process of the permeate side, the hydrophobic membranes with non-woven support exhibit higher pressure resistance, capable of withstanding pressures exceeding 200 kPa. Through experimental and theoretical analyses, the influences of different operation conditions and membrane properties on system performance were studied. Furthermore, utilizing solar energy as the heat source, a case study was conducted based on real meteorological data from a typical coastal city over a consecutive 72-hour period. In the solar-driven PGTO system with a power capacity of approximately 150 kW, the exergy efficiency can achieve 1.04 %, with a power density surpassing 0.1 W m−2, and an average daily freshwater production of over 70000 t. The energy storage function enables stable power generation within the 72 h, and it can sustain steady operation for nearly 7 h thereafter in the absence of sunlight. This study demonstrated the potential of the proposed PGTO system to efficiently utilize fluctuating low-grade thermal energy.

Simultaneous transport of freshwater and heat: An application to Chinese northern coastal regions

Enormous, clean, stable and cheap freshwater and heat from renewable and sustainable energy systems are of utmost importance to avert consequences of climate change, especially in Chinese northern coastal regions. Simultaneous transport of freshwater and heat is a novel technology for integrated use of nuclear power in the form of hot freshwater production with the potential to overcome the drawbacks of desalination and cogeneration. In this paper we address the performance of next generation supply of freshwater and heat methods. Starting our experience with simultaneous transport of freshwater and heat at an AP1000 nuclear plant, we developed for the first time a validated actual demonstration project to know the thermodynamic performance. The model allows us to understand the crucial methods to improve transport capacity through analysis. Simultaneous transport of freshwater and heat pipeline’s lifespan assessment algorithm is developed to compare proper methods to extend pipeline’s lifespan economically. The relationship between cost in whole lifespan and key parameters like external diameter, wall thickness, transported distance, flow velocity, corrosion rate, inner-coating’s price and lifespan is investigated to obtain sensitivity analysis. We found that (a) simultaneous production of freshwater and heat improves thermal efficiency by 32.61 %; (b) Thicker wall pipelines are low-cost and have stronger ability to resist economic risks and keep low-cost in whole lifespan. However, wall thickness shall be limited; (c) Thicker wall extends lifespan longer and makes cost less than inner coating. In summary, this work points out that freshwater and heat pipeline’s transport capacity should be enlarged with consideration of integrated system to settle freshwater and heat’s enormous demand and large-scale actual projects are needed. Once these technologies are promoted in China coastlines’ thermal plants, Chinese northern areas will benefit from them.

Spontaneous and sustainable multifunctional transpiration generator for simultaneous harvesting of electricity, freshwater and salt

Evaporation driven power generation technology has attracted global interest due to its eco-friendly nature and ubiquitous availability. However, the lower performance, discontinuity of power generation and limited function greatly hinder its wide application. To achieve continuous power generation and simultaneous production of freshwater and salt from seawater evaporation, we constructed a spontaneous sustainable multifunctional transpiration generator (SSMTG) with high performance and multi-functions. The continuous power generation was realized by maintaining a controllable dry/wet interface on a carbon black coated cotton cloth, and capillary-driven spontaneous water supply was achieved via a cotton rope. The open circuit potential, short-circuit current and peak power density of a single SSMTG with size of 9 cm × 3 cm × 0.01 cm were ∼ 0.4 V, ∼23.6 μA and ∼ 14.8 μW/cm3, respectively. In addition, the impacts of various factors on the electricity generation were studied and the underlying mechanism was primarily explored. The device can work for more than 24 h, which also can produce 29 mL of freshwater and 0.825 g of salt. When connected in series and parallel, it could supply power for some common electronic devices, such as an electronic watch. The SSMTG can obtain fresh water and salt while producing electricity, which provides a sustainable and versatile source for various applications.

Modeling and Economic Analysis of MED-TVC Desalination with Allam Power Plant Cycle in Kish Island

In this paper, a system consisting of the Allam cycle and Multi-effect Distillation- thermal vapor compression) MED-TVC( desalination was proposed to reduce the amount of carbon dioxide in the atmosphere. It uses wasted energy for the simultaneous production of freshwater and power. Firstly, analysis of the Allam cycle delineated that the heat capacity suitable for the desalination cycle is estimated to be 100 MW, the amount of heat from the outlet of the compressor. The MED-TVC desalination system, one of the most suitable and the most economical desalination systems, is used to combine the Allam cycle and desalination in the Kish Island, located in the south of Iran. The results of this research indicate that the proposed cycle has a desirable economic performance, and the results of economic analysis using the net present value (NPV) method and internal rate of return (IROR) show the Payback period in this plan is 4.8 years.

Process of Concentrating of Highly Mineralized Waters in an Air-Gap Membrane Distiller

The membrane distillation process for the concentration of highly saline waters using air-gap distillation apparatuses equipped with Russian-made membranes has been studied. It has been shown that the proposed approach provides a fourfold increase in the concentration of solutions with the simultaneous production of fresh water that is suitable at least for technical needs. The results obtained may be of interest for concentrating water of various origins.

Simultaneous production of fresh water and electricity via multistage solar photovoltaic membrane distillation

The energy shortage and clean water scarcity are two key challenges for global sustainable development. Near half of the total global water withdrawals is consumed by power generation plants while water desalination consumes lots of electricity. Here, we demonstrate a photovoltaics-membrane distillation (PV-MD) device that can stably produce clean water (>1.64 kg·m−2·h−1) from seawater while simultaneously having uncompromised electricity generation performance (>11%) under one Sun irradiation. Its high clean water production rate is realized by constructing multi stage membrane distillation (MSMD) device at the backside of the solar cell to recycle the latent heat of water vapor condensation in each distillation stage. This composite device can significantly reduce capital investment costs by sharing the same land and the same mounting system and thus represents a potential possibility to transform an electricity power plant from otherwise a water consumer to a fresh water producer.

Integration of membrane distillation (MD) and solid hollow fiber cooling crystallization (SHFCC) systems for simultaneous production of water and salt crystals

A novel hybrid system of integrating membrane distillation (MD) and solid hollow fiber cooling crystallization (SHFCC) has been successfully developed for simultaneous production of fresh water and inorganic salt crystals from NaCl brine solutions. Porous PVDF hollow fiber membranes consisting of PTFE particles were spun for the MD subsystem, while non-porous PVDF hollow fibers were fabricated as heat exchangers for the SHFCC subsystem. To optimize the operation parameters, the Taguchi's method was utilized for experiment design including three key factors; namely, feed temperature (Tf), distillated amount (Wd) and water amount to wash away the scallant (Ww). Several response factors were experimentally investigated and their signal-to-noise ratios of each response were calculated to identify the optimal settings of control factors. As a result, the best combined parameters to maximize the crystal harvest took place at Wd = 14 g and Tf = 50 °C. Narrowly distributed NaCl crystals with a small mean size of 35–45 µm were successfully generated by the hybrid system, and a relatively long-term MD-SHFCC operation of 15 cycles was conducted to verify the system stability and feasibility. The 15-cycle experiments exhibited an impressive average MD water flux of about 8 kg/m2 h and continuous production of distillate water with a high purity (a NaCl concentration of 0.01 g/L) and NaCl salt crystals with a yield of 64 g per kg feed.

Advancement in the Technology of Solar Powered Liquid Desiccant Systems for Fresh Water Production from Atmospheric Humidity

This paper reviews the advances being achieved in a novel promising technology of producing fresh water from atmospheric humidity using solar powered liquid desiccant systems (LDS). It discusses the principle of operation of this technology as well as the historical development of its concept and performance based on previous relevant works in the literature. The review also indicates the prospects of commercializing such a novel fresh water generator. Furthermore, the key parameters that influence the performance of the surveyed technology system have been identified , namely, liquid desiccant (LD) material, LD solution concentration, flow configuration, temperature and relative humidity of the process air, LD solution temperature, solar radiation intensity, bed material of the system units and the ratio of LD mass flow rate to process air mass flow rate. Accordingly, the authors concluded the potential of combining liquid desiccant fresh water generator (LDWG) with solar chimney power plant (SCPP) for the purpose of efficient and feasible simultaneous production of fresh water and electricity.

Highly stable hydrophobic SiNCO nanoparticle‐modified silicon nitride membrane for zero‐discharge water desalination

Membrane distillation water desalination can attain a significantly higher water recovery than reverse osmosis, while the lack of stable hydrophobic membranes limits its commercial applications. This article presents the preparation of a new hydrophobic membrane by modifying a porous Si3N4 substrate with vesicular SiNCO nano‐particles. The membrane had a water contact angle of 142°, due to the presence of –Si–CH3 terminal groups and the high surface roughness. The contact angle remained nearly the same after exposures of the membrane to boiling water, aqueous solutions with pH ranging from 2 to 12, and benzene. The membrane exhibited satisfactory water desalination performance on highly concentrated NaCl solutions and simulated seawater. With the highly stable membrane, it is promising to develop a zero‐discharge water desalination process for simultaneous production of fresh water for daily uses and brine for industrial uses. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1272–1277, 2017

Design and test of a single effect thermal desalination plant using waste heat from m-CHP units

This work refers to an innovative integrated system for the simultaneous production of fresh water and electricity. In particular, a 1 kWe Stirling engine coupled with a thermal desalination plant has been considered for the purpose. The prototype, which refers to the distributed micro cogeneration field, has the final aim of building and testing a single effect distillation plant with a fresh water production of about 150 L/d.Firstly, thermodynamic theories and numerical analysis have been carried out to define the final prototype configuration. Then, an experimental test phase has been carried out to evaluate the actual plant performance.The experimental analysis has been in good agreement with the predicted results. In particular, at nominal operating conditions (@50 °C) the maximum heat transfer rate was higher than the evaporator heat exchanger designed condition (5.5 kWt). Despite the non-ideal plant thermal insulation, fresh water production reached a maximum of about 7 L/h at best operating conditions, proving a good process efficiency. According to the behavior predicted by the model, fresh water production is strongly dependent on the temperature difference between the heating fluid and the salt water in the evaporator tank while it is weakly influenced by the salt content of the treated water. Moreover, the apparatus exhibited a very good response to varying thermal power input thus confirming the opportunity to feed the desalination plant also with different forms of waste heat. More precisely, the plant average efficiency was about 1.3 L/kWh of energy input with minimum and maximum values equal to 1.16 and 1.42 L/kWh.Definitely the proposed solution, studied for a coupling with a 1 kWe Stirling engine, can be easily applied also to the other micro-CHP technologies.

Proposal and analysis of a high-efficiency combined desalination and refrigeration system based on the LiBr–H 2O absorption cycle—Part 1: System configuration and mathematical model

Simultaneous production of fresh water and refrigeration are often required, e.g. in warm-climate water-deficient regions, and this study is a proposal and analysis of an efficient way of producing both of them by consuming mainly low-grade heat. After introducing the configuration choice methodology, a combined refrigeration and water system, ARHP–MEE (absorption refrigeration heat pump and multi-effect evaporation desalter), which is the integration of a LiBr–H 2O refrigeration unit, a LiBr–H 2O heat pump, and a low-temperature multi-effect evaporation desalination unit, is proposed, and the mathematical model is presented and validated. The model serves for conducting a performance analysis of the combined system, reported in Part 2 of this two-part paper.

System analysis of dual purpose cycle for desalinated water and power production

A comprehensive study of the characteristics of a solar powered dual purpose plant for simultaneous production of fresh water and electric power was carried out. The dual purpose (hybrid) cycle consisted of an open water cycle and a Freon-12 closed power cycle interlinked in the heater and condenser of the power cycle. The hybrid system operating conditions and criteria for adjusting the ratio of fresh water production to power generation was described and their effects on the total system were evaluated. The results indicated an increase of both desalinated water and output work with the increase of hot water pressure and temperature. The increase of maximum pressure in the power cycle decreases the amount of desalination and increases the output work up to a certain limit. The inlet water temperature has no effect on the rate of fresh water production, but its increase results in a decrease in the output work. The system study showed the advantages of the proposed cycle as compared to other single purpose plants for desalination or power generation.