Evaporation System Research Articles

Solar interface evaporation system multi-field synergies boost water purification and blue energy harvest technologies

The escalating water and energy crises have led to attempts at combining purifying water and blue energy harvesting using solar interfacial evaporation systems (SIESs) based on hybrid systems. The thermally-localized...

Profile of red wine partially dealcoholized with a membrane-based technique and strategies to mitigate the loss of volatile compounds

In recent years, climate change has led to higher grape must sugar content and, consequently, increased alcohol by volume. Evaporative or pertraction is a common method for post-fermentation ethanol removal from wines, but it selectively removes some less polar volatile compounds along with ethanol.To mitigate volatile substance loss, this study investigates blending of the red wine (Marzemino-Cabernet blend) with obtained dealcoholized samples from it by industrial evaporative pertraction system, while maintaining the final product within a two-percentage-point reduction in ethanol. Thus MIX 1 and MIX 2 blends were prepared, reducing the ABV of the initial wine (12.5% alcohol by volume) to 10.5% and 9.5%.Chemical analyses highlighted that most alcohols, acetates, and ethyl esters of fatty acids decreased with alcohol by volume reduction. However, compounds with polar groups (acetoin and acetovanillone), C13-norisoprenoids, and certain lactones showed increasing trends. Sensory analysis indicated high scores for sweetness and smoothness in the blended wines, with a decrease in acidic taste. Floral scents notably increased, particularly in MIX 2, closely resembling the initial wine’s sensory profile.The blending of initial wine with appropriately dealcoholized wine samples has proven to be an effective strategy for preserving bouquet and color of dealcoholized wines. This approach broadens the consumer base by catering to people who prefer low-alcohol options, have dietary restrictions, or are health-conscious, but who still wish to savor wines with aromatic quality rather than a flat taste. This strategy is crucial in the wine industry as it successfully addresses technical challenges and ensures economic viability.

A convenient-accurate optimization method of the multi-effect evaporation system

In this work, a convenient-accurate multi-effect evaporation system optimization method that integrates regression analysis and a multi-objective genetic algorithm has been proposed to optimize the design of the multi-effect evaporation system. Firstly, a multitude of numerical simulation calculations are conducted employing precise thermodynamic models. Secondly, regression analysis is performed on the experimental data to establish the approximate model between the design variables and performance parameters. Finally, NSGA-II, a non-dominated sorting genetic algorithm with an elite strategy, is employed to optimize and solve the approximate model derived from regression analysis. Consequently, a series of Pareto solutions satisfying the given conditions are obtained. The two initial schemes of the FF-MEE (forward-feed) system and the PF-MEE (parallel-feed) system are optimized using the proposed optimization method. The results show that following optimization, the Gained Output Ratio (GOR) of the FF-MEE system is increased by 3.6%, while the specific heat transfer area (As) is reduced by 16%. Similarly, for the PF-MEE system, the GOR is enhanced by 7.8%, and As is decreased by 19%. The proposed method provides a comprehensive set of optimization solutions, ensuring rapid solution speed, straightforward application, and high solution accuracy.

Super stable evaporators based on upcycled self-healing adsorbents for wastewater regeneration

Establishing a self-healing platform for the removal and resource recovery of heavy metals, enabling heavy metal-free drinking water.

Water evaporation systems for the simultaneous generation of electricity and water desalination: a review

In recent years, people have been committed to obtaining clean water and electric energy through solar interface evaporation, a common phenomenon in nature.

Effect of a static magnetic field on the falling-film evaporation on a vertical plate evaporator by mixed convection

The application of a magnetic field to a falling-film evaporation system can have several effects. The magnetic field can alter the liquid film's flow behavior and modify the system's heat transfer characteristics. The numerical study of falling film evaporation by mixed convection on a vertical channel under a static magnetic field has been investigated. The vertical channel is composed of two parallel plates. The right plate is dry and isothermal, while the left plate is wetted by a falling liquid film and exposed to a static, uniform heat flux from the outside. Water film makes up the liquid, while dry air and water vapor make up the gas mixture. The results relate to the effects of the magnetic field on heat and mass transfer and on liquid film evaporation. The results demonstrate that the static magnetic field has a weak effect on heat and mass transfer and water film evaporation. In fact, it is shown that an increase in the static magnetic field weakly enhances heat and mass transfer as well as liquid film evaporation.

3D inverted cone hydrogels derived by MXene-TiOX nanocomposite for sequential regulation of enhanced solar-driven steam generation

Solar-driven steam generation technology is an environmentally friendly, cost-effective means of sewage treatment and seawater desalination. A significant challenge in the development of this technology is improving the evaporation performance of evaporation devices. Herein, we report an innovative three-dimensional (3D) solar evaporator constructed with MXene-TiOX nanocomposite as the photothermal layer and polyvinyl alcohol hydrogel as the water-transport medium. An inverted cone-concave structure of 30° on the photothermal layer can absorb more sunlight through diffuse light reflection. The 3D solar evaporator demonstrates a notable evaporation rate of 2.09 kg m⁻² h⁻¹ , surpassing the efficacy of alternative evaporative systems. In the seawater desalination experiment, the condensed water had salinity levels that were considerably lower than the established threshold for drinking water. The ion rejection ratios for the four primary ions demonstrate a high level of efficacy, with values approaching 99.91%. In addition, the 3D solar evaporator exhibits robust performance in the context of wastewater treatment. This study provides significant contributions to the understanding of the efficiency of solar evaporators based on structural design principles, offering approaches to mitigate the challenges posed by limited freshwater availability.

Performance Evaluation of Evaporative Cooling Systems as Alternative for Increasing the Shelf Life of Perishable Crops at the Farmer Level in Vunjo-Moshi Rural

Postharvest handling in developing countries continues to be a major challenge for most of the farmers. The low economy in these countries is counted as a major obstacle toward the adaptation of modern postharvest technologies. The present study aimed to assess the existing post-harvest handling practises and test the suitability of evaporative cooling systems for reducing post-harvest losses by using Vunjo-Moshi Rural as a case study. A total of 30 questionnaires covering small commercial farmers were utilised to get information regarding the existing post-harvest handling practices in Vunjo. Two evaporative cooling systems, the Charcoal Cooler Chamber and Sand Cooler Chamber, were created and tested in Vunjo. Their effectiveness was measured by their response to temperature and humidity changes. Results indicated that 87% of the small farmers in Vunjo used local precooling and cold storage methods characterised by low efficiency. Further results showed 77% of all spoilage crops were randomly disposed of in the environment regardless of their impacts. Performance results of designed evaporative systems showed that the Charcoal Cooler Chamber (at its highest performance), could lower the daily ambient temperature by 8.8 °C while increasing the ambient relative humidity from 73.01% to 90.93%. The Sand Cooler Chamber could reduce the daily ambient temperature by 7.8 °C and increase the ambient relative humidity from 73.01% to 93.90%. The performance of both designed systems met the recommended standard for increasing the shelf life of most of the perishable crops cultivated in Vunjo, making them recommended as alternative precooling and cold storage technologies.

Z-Scheme heterojunction WO3/ZnIn2S4 solar absorber for wastewater remediation

Z-Scheme heterojunction, recognized as one of the optimal methods for the separation of electrons and holes, is extensively applied in the domain of photocatalytic. Leveraging the Z-Scheme heterojunction for photocatalytic and solar interfacial water evaporation presents a promising solution for the purification of dye wastewater and the mitigation of organic pollutant accumulation on traditional solar absorbers. In this study, WO3/ZnIn2S4 heterojunction was synthesized through a two-step solvothermal method, and resulting WO3/ZnIn2S4, which rested on a flexible substrate Ti mesh, possessed the dual functionality of interfacial water evaporation and photocatalytic treatment of dye wastewater, which not only water evaporation rate for WO3/ZnIn2S4 reached 1.26 kgꞏm−2ꞏh−1 but also the Z-Scheme heterojunction WO3/ZnIn2S4 empowered it to effectively degrade dye wastewater, with a degradation rate of Rhodamine B up to 98.6%. The harmonization of these two functionalities effectively circumvented the issue of secondary pollution commonly associated with dye wastewater treatment. This study effectively integrates photocatalysis into a cutting-edge solar-driven interfacial evaporation system, effectively expanding the capabilities of a multifunctional solar absorber and introducing novel applications for zero-discharge dye wastewater treatment.

Salting-out/sacrificial template strategy for the preparation of hydrogels as efficient solar evaporators

Hydrogels have recently emerged as promising solar evaporators due to their exceptional high evaporation rates. However, the high costs and complexity associated with the conventional freezing-thawing processes pose challenges that hinder their widespread application in large-scale solar evaporation systems. Herein, we present the successful attempt to prepare hydrogel-based solar evaporators using a salting-out/sacrificial template strategy, where salt particles serve as both salting-out agents and sacrificial templates. Without the need for freezing processes, we successfully synthesized polyvinyl alcohol (PVA) hydrogels, incorporating copper oxide and antimony-doped tin oxide particles as solar absorbers. It is demonstrated that the salting-out (Hofmeister) effect enables the cross-linking of PVA polymeric chains, imparting significant mechanical strength and durability to the hydrogels. Meanwhile, the use of salt particles as sacrificial templates creates well-developed microchannels of 100–300 μm within the hydrogels, enabling rapid water delivery. These hydrogels exhibited a solar-weighted absorptivity of 93.4 % and achieved solar evaporation rates exceeding 3.0 kg m-2h−1 under one-sun illumination. Notably, their performance is comparable to that of state-of-the-art hydrogels prepared using freezing-thawing methods. As such, this proposed strategy holds great promise for the large-scale and cost-effective production of hydrogels as high-performance solar evaporators.

Thermodynamic and environmental analysis of an integrated multi-effect evaporation and organic wastewater supercritical water gasification system for hydrogen production

Organic wastewater poses significant environmental and human health risks. Supercritical water gasification (SCWG) presents a promising approach for converting organic waste into hydrogen-rich mixed gases. Nevertheless, the high moisture content present in organic wastewater hampers the energy efficiency of the SCWG process. To tackle this challenge, we have designed and developed an organic wastewater SCWG hydrogen production system incorporating a multi-effect evaporator. The developed system demonstrates the ability to achieve autothermal conditions for the treatment of swine wastewater with a solids concentration of 4.3%. Notably, this system exhibits impressive energy efficiency, reaching a maximum value of 44.88%, along with an exergy efficiency of 33.90% when processing 7% swine wastewater. Exergy analysis further reveals that the incorporation of a multi-effect evaporator leads to a reduction in exergy destruction within the gasification unit, oxidation unit, and heat exchanger. These improvements highlight the positive impact of the multi-effect evaporator on the overall performance of the supercritical water gasification system. Sensitivity analysis indicated that suitable concentrated concentration and an appropriate amount of preheated water can improve hydrogen production. The system minimum GWP reaches 5.27 kgCO2-eq/kgH2 after adding the CCUS. This work expands the range of applicable feedstocks for the autothermal SCWG process.

High-efficiency and sustainable sodium humate aerogel evaporator for solar steam generation

The utilization of solar interface evaporation technology (SIET) for freshwater production from seawater and sewage is a sustainable, green, viable, and promising approach. However, the absorption rate of sunlight, evaporation rates, and high costs still pose large-scale solar steam generation. In this paper, a novel aerogel (named SAS) was prepared by graft copolymerization with sodium alginate (SA), acrylic acid (AA) and sodium humate (SH) in aqueous solution, using N, N′-Methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator, which has high light absorption (90 %), high porosity (87.96 %), superhydrophilicity (35 ms), low thermal conductivity (0.23 W m−1 k−1). The evaporation rate of SAS aerogel can reach up to 1.66 kg m-2h−1 under 1 kW m−2 light intensity, and the reusability and reliability of SAS aerogel are verified by 10 cycles of experiments. The utilization of this SAS aerogel holds significant implications for the design and fabrication of cost-effective, high-performance solar steam evaporation systems, thereby offering promising solutions to address global freshwater shortages and enhance wastewater treatment efficiency.

Synergistic dual-mechanism raised structure and vertically aligned porous 3D hydrogel fabric for ultra-high salt-resistant water desalination

A solar evaporator with simple fabrication process, exceptional photothermal conversion efficiency and dependable continuous water evaporation holds significant potential for seawater desalination and wastewater treatment. Despite the substantial research dedicated to developing high-efficiency solar evaporators, there remains a need for additional exploration to tackle concerns such as salt crystallization, low evaporation efficiency, poor durability and stability. Here, an efficient water transport PVA hydrogel (water transport layer) and polydopamine/carbon black modified 3D raised-fabric (photothermal layer) are innovatively designed as solar evaporators. The synergistic effect between the periodic raised structure and polydopamine/carbon black results in outstanding photothermal conversion capabilities of PDA/CB@RF. Meanwhile, the porous structure of PVA hydrogel and its vertically aligned channels facilitate ion exchange and ensure a consistent water supply to the photothermal layer. This phenomenon serves to prevent the accumulation of salt in the photothermal layer, thereby markedly enhance the water evaporation capability of the PDA/CB@RF evaporator. The results demonstrate that the PDA/CB@RF evaporator system exhibits excellent photothermal conversion performance with its surface temperature rapidly ascending to 73.3 ℃ under 1 sun light intensity, and effectively boost the water evaporation rate (1.73 kg m-2h−1, 1 sun). Furthermore, the PDA/CB@RF evaporator exhibits excellent conversion efficiency (91.9 %) and self-desalting capability. Overall, this solar evaporator system with a 3D raised fabric design integrates light and thermal energy, consistent water evaporation and self-desalting functionalities, which makes it hold the potential to solve the pressing challenge of water shortage.

Effective treatment of leachate concentrate from waste incineration plant by combination of coagulation and direct contact evaporation

In order to verify that coagulation as pre-treatment can reduce the temperature of the hot air used for direct contact evaporating the leachate concentrate (LC) and low-grade waste heat such as exhaust steam in the waste incineration plant can be used to evaporate the LC. The supernatants after coagulation using polymerized ferrous sulfate (PFS), polymeric-aluminum (PAC), polymeric silicate aluminum ferric (PSAF) and poly-aluminum ferric chloride (PAFC) as coagulants were further treated in a lab-scale direct contact evaporation system. The results showed that the best performance with removal efficiencies of COD and NH3–N of 58.70% and 29.09% was achieved after coagulation when PAFC dosage = 15 g/L, PAM dosage = 30 mg/L and initial pH of supernatant = 6. After coagulation, a large amount of the fulvic-like acid and aromatic heterocyclic compounds were removed and the degree of complexity and aromaticity of organics decreased. After direct contact evaporation, using PAFC as coagulant still was the best selection due to its lowest concentrations of COD and NH3–N (22 mg/L and 1.02 mg/L) in the condensate produced by this two-stage treatment when initial pH of supernatant was 6 during evaporation and the condensate produced by this two-stage treatment met the water quality standard for using as supplying water for circulating cooling water system when temperature of hot air used for heating LC was at low temperature (250 °C). The fulvic-like acid and aromatic heterocyclic compounds in the condensate continuously reduced. Phenol, adamantane, 1-isocyanato, phthalic anhydrid, tri(2-chloroethyl) phosphat, Heptadecane, 2-methyl, ginsenol and Octadecane, 2-methyl- in the condensate obviously decreased. The effect of four coagulants as pretreatment on reducing the temperature of hot air used for evaporating LC was ranked as PAFC > PFS > PAC > PSAF. PSAF was not recommended due to the large amount of NH3–N produced when using PSAF to treat the LC.

Growth‐Mode‐Modulated Defects in Non‐Hydrogenated a‐Si Thin Films for Photothermal Conversion

Nanostructured Si exhibits superior photothermal performance and is a cost‐effective solar absorbing material for solar evaporation, photothermal catalysis, and solar power systems. Defects are effective nonradiative recombination centers and are suppressed in amorphous silicon (a‐Si) to benefit radiative recombination. In this research, a bottom‐up approach to optimize the disordered and defective structure of non‐hydrogenated a‐Si by magnetron sputtering for photothermal conversion is proposed. The 2D mesoporous structure is developed in a‐Si thin films under the growth scenario with reduced nucleation density. Local disorder and defects are analyzed based on the vibrational response of Si‐Si bonds. Accompanied by narrowed bandgap (Eg) of 1.06 eV (Eu) and elongated Urbach tail of 0.49 eV, prominent short‐range disorder and substantial amounts of dangling bonds contribute to enhanced solar absorption. Thereby, the full‐spectrum absorptance above 92% can be realized with antireflection coatings of SiO2/Si3N4. The electron–phonon behavior revealed by resonance Raman scattering provides a comparative study on phonon production. Stronger electron–phonon coupling originated from the defective structure can be achieved at larger Eu. Provided with narrowed Eg and elongated Eu, local disorder and coordinative defects benefit both broadband absorption and thermal production, which can be introduced with controlled nucleation density and arrival rates.

Techno-economic and environmental analysis of high temperature heat pumps integration into industrial processes: the ammonia plant and pulp mill cases

Heat pumps will play an important role in improving the performance of the industrial processes aiming to decarbonize their heating requirements. Yet, defining the best operating conditions of those devices may be a challenging task, as they are embedded in larger energy conversion systems and in direct competition with fired and electric heaters and other waste heat recovery systems. The costs of the energy inputs also influence the selection of either a heat pump or a gas boiler, which affects the overall efficiency and the incremental cost of the final solution. Thus, a systematic analysis must be applied in order to determine the best option to supply the heating requirement, without considerably impacting the operational feasibility of the overall plant. In this work, the base-case performance of two industrial applications with intensive heating demand, namely, the solvent regeneration process of a carbon capture unit and the black liquor concentration process of a kraft pulp mill, are compared to that of the scenarios in which a high temperature heat pump or a mechanical vapor recompression unit are integrated, aiming to reduce the energy consumption and the environmental impact. The benefits of the integration of a heat pump or a mechanical vapor recompression unit over a conventional reboiler and a multiple effect evaporation system are discussed in the light of thermodynamic, economic and environmental indicators. As a result, the alternative approaches remain competitive vis-à-vis the conventional solutions in terms of energy consumption and operating costs. In addition, the emissions associated to the heating applications could be reduced by 45% if a high temperature heat pump is integrated. The optimized solution using a heat pump has an overall exergy efficiency 9% higher compared to the typical configuration of the ammonia plant. In pulp mills, the integration of mechanical vapor recompression systems slightly affects the performance compared to the conventional scenario with a multiple effect evaporation system.

Nature‐Inspired Structure‐Engineered TiN/TiO2 Nanotubes Array Toward Solar Desalination Synergy with Photothermal‐Enhanced Degradation and Thermoelectric Generation

AbstractSolar‐driven interfacial evaporation systems are considered as promising technology to alleviate the water scarcity crisis, yet lack of innovative evaporators obstructs further improvement of energy utilization efficiency. Herein, inspired by mangrove, the structure‐engineered design is utilized to synthesis multi‐level reflection TiN/TiO2@carbon cloth (CC) nanotubes array. The hollowed TiO2 nanorods can promote expeditious water transport, while the TiN/TiO2 array can act as localized surface plasmon resonance (LSPR)‐enhanced multi‐level reflection structure for solar energy harvesting. The enhanced light absorption capability of the bionic nanostructure is confirmed by finite‐difference time‐domain (FDTD) simulations. Therefore, the TiN/TiO2@CC‐3 exhibits high evaporation rate of 2.02 kg m−2 h−1 under 1 solar illumination, which is comparable or better than most of fabric‐based evaporators. When applied in wide acid–base (pH 1–13) and salinity range (8–100 ‰) over 15 days, the TiN/TiO2@CC‐3 displays outstanding durability. Furthermore, to expand application scope of the elaborate nanostructure, photothermal‐enhanced photocatalysis and thermoelectricity generation applications are evaluated, while these new functionalities are integrated into solar‐driven desalination system. The outdoor device exhibits daily water yield of 10.89 kg m−2, synergy with maximum 200.7 mV output voltage and high dye degradation efficiency, demonstrating flexible applications in multi‐functional interfacial evaporation systems according to various requirements.

Crystallization of sucrose by using microwave vacuum evaporation

Sucrose crystallization was performed by using a custom designed microwave vacuum evaporation system. Process was designed to mimic a semi-batch crystallization starting from beet syrup concentration to crystal slurry formation. The effect of microwave power and feeding time on the process yield and product attributes (particle size, solution color and turbidity) were investigated. Microwave treatment was shown to affect the sucrose crystal morphology and the quality parameters significantly. Process yield was significantly affected by both crystallization power and feeding time (p < 0.05). Longer feeding time (15 min) and medium microwave power (30%) resulted in the highest process yield (∼55%). The results revealed that microwave processing can be a promising alternative over commercial crystallization.

The manipulation of the interfacial evaporation property of graphene porous membranes

Graphene membranes of excellent solar absorption and photothermal conversion efficiency have been used in solar-driven water evaporation (SDWE) systems as light-harvesting material. The interfacial evaporation property between graphene membranes and seawater is an important issue to further promote the development of SDWE. In this work, manipulation strategies are presented based on porous structures for tailoring the evaporation performance of graphene membranes. The non-equilibrium molecular dynamic (NEMD) simulation results show that the pore size, pore concentration, and distribution pattern are all key factors in enhancing the evaporation rate. The evaporation performance can achieve the best optimisation when the pore size is 3.1 Å and the pore concentration is the lowest. Moreover, the periodic distribution of porous structures can greatly increase the evaporation rate (about 100 water molecules per nanosecond) due to the improvement of adsorption and desorption balance compared with the random structure. The optimised configuration of the graphene porous used in SDWE systems is proposed, which could increase the evaporation rate to 357.1%. This study could provide some theoretical guidance on graphene membranes for application in both photothermal conversion and solar-driven water purification.

Hierarchical Cu dendrites@ CuO multifunctional nanowire mesh for solar-thermal clean water production

Solar-driven interfacial evaporation is recognized as an energy-efficient and sustainable approach to combat the global freshwater crisis, particularly in rural areas where continuous energy inputs are limited. Additionally, these regions often lack effective sterilization methods for their water sources. By incorporating photothermal materials with inherent antibacterial properties, water purification can be enhanced without relying on external sterilization steps. Herein, we designed a multi-functional photothermal (MFP) evaporator based on a Cu dendrite@ CuO with abundant nanowires via a template-free method for solar-thermal clean water production. Compared to flat-type structures, the MPF evaporator with its dendritic architecture not only exhibits efficient photon absorption but also expands the evaporation area by over sevenfold, facilitating enhanced water evaporation with an efficient pathway for water transfer. Under 1 kW m−2, the MFP evaporator achieves an impressive evaporation rate of 1.40 kg m−2 h−1 and an efficiency of 87.8 %. Furthermore, the MFP evaporator demonstrates remarkable antibacterial capabilities, effectively inhibiting bacterial growth in raw water by damaging bacterial cell walls. Hence, the as-prepared MFP evaporator exhibits tremendous potential as an innovative system for solar-driven interfacial water evaporation and purification.