Laboratory-scale Device Research Articles

Characterization and Modeling of Gravity-Driven Flashing of Superheated Water in a Pool Heated from Below

Gravity-driven flashing of superheated water, the topic of this paper, is a phase change phenomenon that is tightly linked with some of the safety issues of a spent-fuel-pool loss-of-cooling accident. As detailed in this article, the phenomenon has been empirically studied and characterized within the Aquarius laboratory-scale experimental device. Primarily, the performed tests unveil the occurrence conditions of the gravity-driven flashing phenomenon in a pool heated from below and its coupling with the degassing of dissolved gases that may take place within the liquid. Next, a set of dimensionless correlations describing the studied heat and mass transfers is derived from the data and presented for both the single-phase and the two-phase regimes of any conducted test. Then, a lumped-parameter model, relying on those correlations and describing the studied physics, is introduced. The model resolves the coupled mass and energy balance equations of the heated liquid pool. Last, this model is used to simulate a selected reference test. The performed simulations are successfully compared with the available empirical data, with moderate discrepancies, thereby verifying the adequateness of the proposed model.

Experimental study of fire propagation along a vertical wall in a lab scale device

Experimental study of fire propagation along a vertical wall in a lab scale device

Experimental Device for the “Green” Synthesis of Unbranched Aliphatic Esters C4–C8 Using an Audio Frequency Electric Field

One of the most important reactions in organic synthesis is esterification, and the compounds generated using this process are esters with a wide range of applications in various industries. Numerous approaches have been employed to enhance the ester yield and reaction rate and establish equilibrium in esterification reactions. This study uses a non-catalytic thermal esterification method to obtain unbranched aliphatic esters C4–C8. The effect of an audio frequency electric field instead of a catalyst on the esterification reaction between acetic acid and linear C4–C8 aliphatic alcohols was studied. The main goal of this study was to design and implement a lab-scale device for the synthesis of aliphatic esters in an environmentally sustainable manner using only specific raw materials and an audio frequency electric field at 3 and 6 kHz at 20 °C and 50 °C. A mechanism for the esterification reaction using an audio frequency electric field is also suggested. The proposed experimental device is designed to produce esters in a green and cost-effective manner and could be used on a large scale in the food, cosmetics, and pharmaceutical industries.

Feasibility of effective separation of NaCl and Na2SO4 after simultaneous crystallization from solution

The hetero-salt, a solid waste, is generated due to the simultaneous crystallization and agglomeration of two or more salts in the evaporative crystallization of multi-salt solution. However, the waste can be transformed into resource if the different crystalline particles can be separated effectively. In this study, NaCl and Na2SO4 were taken as examples and mixed in the solution. It was found that the agglomeration of the crystals occurred both in the drying and crystallization stage. But the crystals could be independent at certain concentration and evaporation time. Meanwhile, the morphological characteristics of NaCl and Na2SO4 crystals were quite different. Therefore, a lab-scale overflow device was prepared to separate the mixed crystals. The results showed that it was possible to separate the two kinds of crystals in simultaneous crystallization effectively. The purity of recovered NaCl was up to 97.58% at a flow velocity of 0.04 m/s.

β-Ni(OH)2 / WC for high-energy aqueous hybrid supercapacitor

This study focuses on synthesizing tungsten carbide incorporated β-Ni(OH)2 composite as a positive electrode in asymmetric supercapacitor applications. The composite was prepared for different concentrations of WC (5,10, and 15 wt.%). The bare β-Ni(OH)2 and β-Ni(OH)2/WC composites were tested in the three-electrode system using a KOH electrolyte. The characteristics performances were optimized based on the electrochemical performance of the three electrode configurations. The typical lab-scale asymmetric supercapacitor device delivered a maximum specific energy of 66.78 Wh kg−1 at ⁓0.3 A g−1 in a 2 M KOH electrolyte medium. Further, the pouch-type supercapacitor was fabricated using a PVA-KOH hydrogel electrolyte. The pouch cell delivers a specific energy of 18.69 Wh kg−1 at a specific power of 3.282 kW kg−1 at 1 A g−1. The supercapacitor also shows a capacitance retention of 76 % even after 17,000 cycles at 1.25 A g−1. Thus, it is evident that an optimum composition of the β -Ni(OH)2 / WC(5 wt.%) composite will be an effective positive electrode in an asymmetric supercapacitor for obtaining high specific energy.

A sustainable integrated anoxic/aerobic bio-contactor process for simultaneously in-situ deodorization and pollutants removal from decentralized domestic sewage

The integration of anoxic filter and aerobic rotating biological contactor shows promise in treating rural domestic sewage. It offers high efficiency, low sludge production, and strong shock resistance. However, further optimization is needed for odor control, pollutant removal, and power consumption. In this study, the investigation on a one-pump-drive lab-scale device of retention anoxic filter (RAF) integrated with hydraulic rotating bio-contactor (HRBC) and its optimal operation mode were conducted. During the 50-day operation, optimal operation parameters were investigated. These parameters included a 175 % reflux ratio (RR), 5-h hydraulic retention time in the RAF (HRTRAF), and 2.5-h hydraulic retention time in the HRBC (HRTHRBC). Those conditions characterized a micro-aerobic environment (DO: 0.6–0.8 mg/L) in RAF, inducing improved deodorization (89.3 % sulfide removal) and denitrification (85.9 % nitrate removal) simultaneously. During the operation period, 84.79 ± 3.87 % COD, 82.71± 2.06 % NH4+-N, 74.83 ± 2.06 % TN, 91.68± 2.12 % S2−, and 89.04 ± 1.68 % TON were removed in RAF-HRBC. Based on large amount of operational data, organic loading rate curves of RAF-HRBC were validated and calibrated as a crucial reference to aid in full-scale designs and applications. The richness of microbial community was improved in both RAF and HRBC. In the RAF, the autotrophic sulfide-oxidizing nitrate-reducing bacteria (a-son) and heterotrophic sulfide-oxidizing nitrate-reducing bacteria (h-son) were selectively enriched, which intensified the sulfide removal and denitrification process. In the two-stage HRBC system, the 1st stage RBC was primarily composed of organics degraders, while the 2nd stage RBC consisted mainly of ammonium oxidizers. Overall, the integrated RAF-HRBC process holds significant potential for simultaneously improving pollutant removal and in-situ odor mitigation in decentralized domestic sewage treatment. This process specifically contributes to enhancing environmental sustainability and operational efficiency.

Selective production of levoglucosenone from catalytic pyrolysis of regenerated cellulose from a H3PO4-H2O system

A series of regenerated cellulose (RC) were prepared by a H3PO4-H2O system with different H3PO4 concentrations. The effects of H3PO4 concentrations on the physicochemical properties of RCs were studied, including crystallinity index (CrI), hydrogen bond energy (EH), accessibility, and degree of polymerization (DP). The catalytic pyrolysis experiments of RCs were executed with a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) instrument and a lab-scale device, to investigate the regulatory function of cellulose structure on the LGO formation. The results indicated that the H3PO4-H2O system could transform the cellulose crystal form from Ⅰ to amorphous form, reduce its CrI and EH significantly, improve its accessibility, while had slight effects on the DP. These changes made RC more appropriate for the selective preparation of LGO, and the corresponding optimal catalyst loading and pyrolytic temperature were also decreased significantly. With phosphoric acid activated carbon as the catalyst, the highest yield of LGO from RC in Py-GC/MS experiments reached 21.50 wt% at catalyst/cellulose (Cat/Cel) ratio of 1/5 and 270 °C, which was much higher than the 18.16 wt% of LGO gained from untreated cellulose at Cat/Cel ratio of 1/3 and 300 °C. In the lab-scale device, the maximum LGO yield from RC was 17.09 wt% at 270 °C and Cat/Cel ratio of 1/6.

Patch-healed grain boundary strategy to stabilize perovskite films for high-performance solar modules

The industrialization of organic-inorganic hybrid perovskite photovoltaic devices needs to be further promoted, while the efficiency and stability modules should be seriously considered. We have developed an on-surface conversion patch healing strategy for polycrystalline perovskite films via 1,3-diisopropyl-4,5-difluorobenzimidazolium iodide ion-based one-dimensional lead-iodide structure. Fluorine atom can interact with another benzimidazolium generating F···H hydrogen bond network to accelerate the charge extraction and transfer in intermolecular region. And, fluorine bonded with formamidinium (FA) ions and immobilized FA to improve the polycrystalline film durability. Attributed to the 1D structure stable chemical properties and specific electronic structure, the lab-scale device gained high efficiency of 24.05% in FACs-based perovskite system. The unsealed cell maintained 94.6% of its initial efficiency over 500 h under AM 1.5 G illumination in N2 atmosphere. And the large-area perovskite modules with high efficiencies (20.56% and 17.7% for the total areas of 36 cm2 and 100 cm2, respectively) fabricated by blade coating process, and the 1D-patch-based modules maintain 92.9% of the initial values after 2200 h of storage in 30% RH and 25 °C, which demonstrated the great application potential of this novel 1D patch healing in the perovskite photovoltaics.

Lab-scale transport and activation of peroxydisulfate for phenanthrene degradation in soil: A comprehensive assessment of the remediation process, soil environment and microbial diversity

Electrokinetic transport followed by electrical resistance heating activation of peroxydisulfate is a novel in situ soil remediation method. However, the strategy of electrokinetic transport coupled with electrical resistance heating and the comprehensive evaluation of restored soil need to be further explored. In this study, a lab-scale simulation device for in situ electrokinetic transport coupled with electrical resistance heating activation of peroxydisulfate was constructed to monitor the transport and transfer of peroxydisulfate, target pollutants, and process parameters, and the physicochemical properties and bacterial community of treated soil were evaluated. The results showed that adding 10 wt% peroxydisulfate to both the anode and cathode resulted in the optimized transfer rate and cumulative concentration of peroxydisulfate under electrokinetics. After 8 h, the cumulative concentration of peroxydisulfate reached 66.15– 166.29 mmol L−1, which was attributed to the migration of a large amount of S2O82− from the cathode to the soil under electromigration. Additionally, the anodic interfacial electric potential was improved, which was more conducive to electroosmotic transport of peroxydisulfate from the anode chamber. By alternating electrokinetic transport and electrical resistance heating activation of peroxydisulfate for two cycles, the phenanthrene degradation efficiency in four evenly distributed wells between electrodes reached 75.4 %, 87.6 %, 92.3 %, and 94.4 %. With slight variations in soil morphology and structure, the electrokinetic transport coupled with electrical resistance heating activation of peroxydisulfate elevated the soil fertility index. The abundance and diversity of bacterial communities in treated soil recovered to above the original soil level after 15 days. Our findings may support the application of electrokinetic transport coupled with electrical resistance heating activation of peroxydisulfate as a promising green ecological technology for the in situ remediation of organic-contaminated soil.

Pengembangan Alat Desalinasi Air Laut dengan Teknologi Thermal Energy Storage

The need for clean water in household life is very important because humans cannot live without it. The composition of seawater consists of 96.5% pure water and 3.5% other materials, namely salts, dissolved gases, and others. Indonesia is one of the countries that has the second-longest coastline in the world, so the potential for utilizing sea water is very large, one of which can be through the desalination process. Distillation itself is distillation, and its by-product is salt when seawater is heated using a heat energy source with a concentrated solar power (CSP) system. Based on research that has been done previously, the tool is a lab-scale seawater desalination device, but the process of making a lab-scale seawater desalination tool is not optimal. Then design the construction of a lab-scale seawater desalination device with the Multi Stage Flash (MSF) type, and the aim is to determine the performance and functionality of the MSF-type lab-scale seawater desalination device. The results show that the results of the coil heat exchanger development obtained an inlet temperature of 85.9°C and an outlet temperature of 67.8°C, and the room temperature in the chamber can be maintained at a temperature of 68.9°C. As for the components being developed, such as sea water pumps, hoses, tees, and sprayers, a sea water debit of 53.78 liters per hour has been obtained.

Desalination performance of shale gas produced water by flow-electrode capacitive deionisation process

The cost-effective desalination of shale-gas produced water (PW) has long been an industrial research hotspot. Flow-electrode capacitive deionisation (FCDI), a recently developed electrochemical desalination technology, may be a novel option for PW disposal because of its attractive advantages. However, reports on the desalination test of actual high-salinity industrial wastewater by FCDI are lacking. In this study, a laboratory-scale FCDI device with an online monitoring system was used to desalinate shale-gas PW. FCDI achieved relatively stable desalination efficiency for pretreated PW with a salinity of 2.65 % and reached an energy-normalised salt removal of 0.479 mg/J. The flow electrode chemically activated by KOH increased the FCDI average desalination rate by 98.5 % for the pretreated saline PW. Electrochemical impedance spectroscopy analysis revealed that the majority of fouling accumulated on the anion-exchange membrane (AEM) side. Residual pollutants were adsorbed by the flow electrode in the AEM chamber, which destroyed the optimal ion-transport path and electric double-layer structure. Results showed that FCDI was more suitable for PW’s reverse-osmosis (RO) permeate desalination to form an RO–FCDI hybrid. This study provided a practical experimental case on the electrochemical desalination of saline PW by FCDI.

Multi-Objective Optimization of a Bi-Metal High-Temperature Recuperator for Application in Concentrating Solar Power

Abstract Supercritical CO2 closed Brayton cycles are a major candidate for future power cycle designs in concentrating solar power applications, with high-temperature recuperators playing an essential role in realizing their high thermal efficiency. Printed circuit heat exchangers (PCHEs) are often chosen for this role due to their thermal-hydraulic and mechanical performance at high temperatures and pressures, all while remaining compact. However, PCHEs can be costly because of the high-performance materials demanded in these applications, and the heat exchanger internal geometry is restricted by their manufacturing process. Additively manufactured heat exchangers can address both of these shortcomings. This work proposes a modular bi-metal high-temperature recuperator with integrated headers to be produced with additive manufacturing. Beginning with existing PCHE channel geometries, a 1D heat exchanger model is developed. Then, multi-objective optimization is used to maximize the heat transfer effectiveness of a lab-scale device while limiting its size. Two distinct channel geometries emerge from the optimization. Optimal designs achieve up to 88% effectiveness with negligible pressure drop. Deterioration of effectiveness due to axial conduction of heat in the heat exchanger walls is found to be a notable problem for lab-scale PCHEs, and the optimal designs obtained here minimize its detrimental effects. A sensitivity analysis reveals that the effectiveness of the recuperator is much less sensitive to variation in mass flowrate in off-design operation when axial conduction is significant, while increasing the length of the device easily increases effectiveness.

Fundamentals of thin film depth profiling by glow discharge optical emission spectroscopy

Glow discharge optical emission spectroscopy (GDOES) is a useful technique for qualitative plasma characterization. It also enables depth profiling of solid materials upon exposure of samples to energetic positively charged ions from gaseous plasma, providing specifics of both surface- and gas-phase collision phenomena that are considered. The early stages of developing GDOES useful for the determination of surface composition and depth profiling of solid materials are reviewed and analyzed, stressing the contribution of early authors. The advantages as well as drawbacks of the GDOES technique are presented and discussed. The recent applications of this technique for depth profiling of various materials are presented, and the directions for constructing a laboratory-scale device are provided.

Systematic covalent crosslinking of graphene oxide membranes using 1,3,5 triazine 2,4,6 triamine for enhanced structural intactness and improved nanofiltration performance

From its physicochemical characteristics, graphene oxide (GO) is a promising versatile next generation membrane material. Its unique characteristics like ultrafast permeation and hydrophilicity makes it a favourable separation membrane nanomaterial in water purification. However, a fundamental problem in the use of GO in nanofiltration is decreased performance overtime due to the pore size widening phenomenon. This paper explored the use of an amine group containing compound, 1,3,5 triazine, 2,4,6 triamine (melamine) to covalently interlink the GO nanosheets to counteract this swelling phenomenon. Prior to membrane fabrication, covalent interactions between GO and the crosslinker, melamine were successfully confirmed through thermogravimetric analysis (TGA), x-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy characterisations. Following these characterisations, crosslinked membranes were successfully fabricated and enhanced nanofiltration performance was confirmed. Resultantly, the surface morphology of the membranes was recorded via Scanning Electron Microscopy (SEM) characterisations while a lab-scale nanofiltration device was constructed for flux and rejection analysis. Evidently, performance improvement with covalent crosslinking was imminent as an up to a 100% rejection of methylene blue was achieved for the crosslinked membranes. Structural integrity of GO membranes has indeed been improved through crosslinking.

Microbead-based extracorporeal immuno-affinity virus capture: a feasibility study to address the SARS-CoV-2 pandemic

In this paper, we report on the utilization of micro-technology based tools to fight viral infections. Inspired by various hemoperfusion and immune-affinity capture systems, a blood virus depletion device has been developed that offers highly efficient capture and removal of the targeted virus from the circulation, thus decreasing virus load. Single-domain antibodies against the Wuhan (VHH-72) virus strain produced by recombinant DNA technology were immobilized on the surface of glass micro-beads, which were then utilized as stationary phase. For feasibility testing, the virus suspension was flown through the prototype immune-affinity device that captured the viruses and the filtered media left the column. The feasibility test of the proposed technology was performed in a Biosafety Level 4 classified laboratory using the Wuhan SARS-CoV-2 strain. The laboratory scale device actually captured 120,000 virus particles from the culture media circulation proving the feasibility of the suggested technology. This performance has an estimated capture ability of 15 million virus particles by using the therapeutic size column design, representing three times over-engineering with the assumption of 5 million genomic virus copies in an average viremic patient. Our results suggested that this new therapeutic virus capture device could significantly lower virus load thus preventing the development of more severe COVID-19 cases and consequently reducing mortality rate.Graphical

Chemical addition to wet webs using foam application

In papermaking, the conventional way to add chemicals to the web is to dose them into the fiber stock and form the paper afterwards. However, in many cases, adding chemicals directly to the stock is challenging. For example, strength aids tend to increase flocculation in the stock, which limits the addition amounts of those aids. The need for better performance of paper (and paperboard) products has given rise to the need for functionalization of paper. Adding such functional chemicals to the stock is usually rather inefficient. Hence, novel methods are needed to add chemicals to the paper bulk. One such method is dosing chemicals to the wet web via foam application. In this study, we built a laboratory-scale sheetfed dynamic foam application device and utilized it to study addition of starch to wet bleached chemithermomechanical pulp (BCTMP) paper handsheets. The impact of parameters such as vacuum level, the amount of added chemical, and the viscosity of the foaming liquid on the penetration of starch into the wet web was explored. Starch penetration into wet webs was measured via iodine-potassium iodide staining, followed by image analysis. According to our results, controlling the viscosity of the foaming liquid gives the best possibility to control the penetration.

Micromixing and Co-Precipitation in Continuous Microreactors with Swirled Flows and Microreactors with Impinging Swirled Flows

One of the promising methods for process intensification for micromixing, co-precipitation, and crystallization in continuous reactors is the use of vigorous vortices. A combination of the high intensity of the kinetic energy input with the small volume of the micromixing volume allows to concentrate the energy dissipation rate up to 104 W/kg and more. As the embodiment of such an idea, four new types of microreactors with intensively swirled flows were created and studied as a tool for continuous co-precipitation and crystallization. A correlation between residence time and segregation index was found: the smaller residence time, the higher energy dissipation rate and better quality of micromixing. A method for the synthesis of oxides of a number of transition metals in microreactors with intensively swirled flows with subsequent thermal treatment of co-precipitation products has been developed. This method was used to obtain ensembles of nanosized particles of zirconium oxides, as well as calcium and strontium fluorides. In comparison with the currently widely used hydro- and solvothermal methods, the proposed method has high productivity (around 10 m3/day for lab scale device), can significantly reduce the duration of the process, provides low energy consumption, does not require a large number of labor-intensive operations, is technologically advanced and easily scalable.

Roadway Embedded Smart Illumination Charging System for Electric Vehicles

Inspired by the fact that there is an immense amount of renewable energy sources available on the roadways, such as mechanical pressure, this study presents the development and implementation of an innovative charging technique for electric vehicles (EVs) by fully utilizing the existing roadways and state-of-the-art nanotechnology and power electronics. The developed Smart Illuminative Charging is a novel wireless charging system that uses LEDs powered by piezoelectric materials as the energy transmitter source and thin film solar panels placed at the bottom of the EVs as the receiver, which is then poised to deliver the harvested energy to the vehicle’s battery. The piezoelectric materials were tested for their mechanical-to-electrical energy conversion capabilities and the relatively large-area EH2N samples (2 cm × 2 cm) produced high output voltages of up to 52 mV upon mechanical pressure. Furthermore, a lab-scale prototype device was developed to testify the proposed mechanism of illuminative charging (i.e., “light” coupled pavement and vehicle as a wireless energy transfer medium).

Calculation and analysis of the flamelet library for numerical modelling of the non-premixed combustion of natural gas in a pilot burner

The flamelet modelling concept has been employed for numerical simulation of the non-premixed combustion of natural gas in a pilot burner of novel type. This prospective laboratory-scale burner device is featured by axial supply of high-speed jet of flue gases, while the fuel (natural gas) and the oxidizer (air) are supplied radially and separately inside the burner chamber. With the use of chemical kinetics mechanism for natural gas (62 species, 398 reactions) the flamelet library has been generated, from its analysis the flame quenching has been determined at the scalar dissipation rate limit of 42 (1/s). From this library the lookup-table of thermochemical solution has been pre-calculated with the presumed beta-function pdf averaging. On this basis the numerical simulation of aerodynamics, heat transfer and the natural gas combustion processes, including soot formation and its effect on radiative heat transfer, has been performed in the considered pilot burner run at the thermal load of 8.8 kW and air excess coefficient of 0.85 (inside the burner body). The distributions of gas species are presented. The predicted NOx emission in exhaust gases is 48.8 mg/m3 for the studied burner regime.

Quantifying and rationalizing polarization curves of Zn-air fuel-cells: A simple enabling contribution to device-scale analysis and monitoring

Zinc-air fuel cells (ZAFCs) with flowing particulate Zn anode are gaining momentum with respect to cognate and competing flow-battery technologies, such as zinc-air batteries with immobilized zinc anode zinc-bromine, zinc-cerium and zinc-vanadium flow-batteries, owing to better energy storage flexibility and control of recharge, as well as environmental compatibility. Notwithstanding its appeal, the ZAFC concept still exhibits several operational aspects that warrant dedicated studies, mainly regarding the impact of operating conditions on anode passivation and air cathode degradation. To this aim, systematic experimentation with real devices and simple, but robust electroanalytical approaches, that would enable quantitative handling of large corpora of experimental data, are highly desirable. The literature available to date, is mainly concerned with specific issues regarding device engineering or cathode materials, while systematic and quantitative work on the electrochemical response of the device is missing. This work contributes to bridging this gap, proposing a simple and physically transparent method to follow the variations of cell response to changes in operating conditions, through the measurement of polarization curves and their fitting with a very simple, but original and robust macro-electrokinetic equation, enabling a clear correlation between overvoltage components and cell state. In addition to original measurements with a self-built laboratory-scale device, we fitted and analysed all ZAFC polarization curves reported in the literature. Parametric analysis of the model is complemented by materials-science data, targeting selected observables, relevant to polarization curve analysis.