Energy Separation Research Articles

Numerical and experimental study of dynamic gas–liquid separator with various viscosities

The gas–liquid separation process is important in various industries, such as electric power, aerospace, and petroleum. This study introduces an innovative, dynamic gas–liquid separator (DGLS) in which a cyclonic flow pattern is induced by blade rotation. This cyclonic flow enhances the efficiency of gas and liquid phase separation while also imparting energy to facilitate the transport of the separated fluid. Numerical simulations are used to analyze the internal flow dynamics, power requirements, and separation efficiency of this DGLS. A comparison with experimental results is conducted to validate the reliability of the numerical model. The effects of liquid-phase viscosity on the internal energy consumption and separation performance of the DGLS are explored at various flow rates. The simulation results indicate that for a given viscosity, the degassing rate of the separator decreases while the liquid removal rate increases as the inlet flow rate rises. Furthermore, it is observed that higher viscosity leads to poorer separation performance, with a decrease in turbulent kinetic energy near the rotating axis and an increase in turbulence intensity near the wall. At lower flow rates, the effectiveness of liquid-phase outlet pressurization improves with increasing viscosity. However, at higher flow rates, increasing viscosity leads to a substantial decline in energy performance and a reduction in liquid-phase outlet pressurization. The increment in turbulent kinetic energy is greater than the square of the mean velocity, indicating a positive correlation between turbulence intensity and turbulent kinetic energy. These findings not only provide a theoretical basis for the prediction of flow losses within a DGLS and the efficient design of these separators, but also provide guidance for industrial applications involving high-viscosity fluids.

Tetrahedral shape and Lambda impurity effect in $^{80}$Zr with a multidimensionally constrained relativistic Hartree-Bogoliubov model

Abstract This study investigates the tetrahedral structure in $^{80}$Zr and Lambda ($\Lambda$) impurity effect in $^{81}_{~\Lambda}$Zr using the multidimensionally constrained relativistic Hartree-Bogoliubov model.
 The ground states of both $^{80}$Zr and $^{81}_{~\Lambda}$Zr exhibit a tetrahedral configuration, accompanied by prolate and axial-octupole shape isomers. 
 Our calculations reveal there are changes in the deformation parameters $\beta_{20}$, $\beta_{30}$ and $\beta_{32}$ upon $\Lambda$ binding to $^{80}$Zr, except for $\beta_{32}$ when $\Lambda$ occupies $p$-orbits. 
 Compared to the two shape isomers, the $\Lambda$ particle exhibits weaker binding energy in the tetrahedral state when occupying the $1/2^+[000](\Lambda_s)$ or $1/2^-[110]$ single-particle states. In contrast, the strongest binding occurs for the $\Lambda$ particle in the $1/2^-[101]$ state with tetrahedral shape. A large $\Lambda$ separation energy may not necessarily correlate with a significant overlap between the density distributions of the $\Lambda$ particle and the nuclear core, particularly for tetrahedral hypernuclei.

Simulation-Based Design for Inlet Nozzle of Vortex Tube to Enhance Energy Separation Effect

The vortex tube, also known as the Ranque–Hilsch vortex tube, is a mechanical device that separates compressed gas into hot and cold streams. It offers a reliable and cost-effective solution to a wide range of cooling applications, as it operates without moving parts, electricity, or refrigerants. Research on vortex tubes has primarily focused on understanding the mechanisms of energy separation and optimizing cooling performance by altering geometric operational parameters. In this study, a Computation Fluid Dynamics (CFD) analysis was conducted to enhance the prediction of energy separation performance and improve the overall energy efficiency of the vortex tube. First, the geometry of the experimental device was modeled to closely match its actual shape, unlike the simplified geometries commonly used in previous CFD studies. Simulations were then carried out with variation in grid systems and turbulence models, and the results demonstrated improved agreement with experimental data compared to those reported in previous studies. Finally, simulations with a modified shape of the inlet nozzle shape were performed, revealing that the energy separation effect of the vortex tube could be enhanced by approximately 15% with an increased inlet expansion ratio (ϵ) while maintaining a constant nozzle length.

SnS2/ZIF-67 nanocomposite: a novel bifunctional, highly efficient, and reusable photocatalyst for enhanced visible-light-assisted biodiesel production and degradation of tinidazole

Herein, a novel bifunctional, highly efficient and reusable visible-light active SnS2/ZIF-67 nanocomposite was fabricated for improved photodegradation of tinidazole (TDZ) and photocatalytic biodiesel production from soyabean oil. An improved photocatalytic performance was ascribed to the enhanced separation of charges and narrow-bandgap energy of the photocatalyst by synergistic- interaction between SnS2 and ZIF-67. Within 60 min of irradiation, more than 96.31± 1.62 % of 15 ppm TDZ could be removed by 0.3 mM H2O2, 0.4 g/L of prepared photocatalyst under mild-conditions. The appraisal of photocatalytic activity of SnS2/ZIF-67 nanocomposite for photocatalytic degradation of TDZ under actual wastewater conditions was studied by introducing various co-existing ions and water matrices. The SnS2/ZIF-67 photocatalyst showed biodiesel yield of 91.25 ± 1.58 % at photocatalyst loading of 3 wt.% and methanol-to-oil ratio of 10:1 within 50 min of light-irradiation. The current research highlighted the potential of metal-sulphides for water remediation and biodiesel production under light-irradiation.

Multi-energy CT and iodinated contrast

Spectral CT acquires images with the emission or detection of two separate energy spectra. This enables material decomposition due to the photoelectric effect (prevalent in low-energy photons) and Compton scattering (prevalent in high-energy photons).Iodine and other materials with high atomic numbers appear more hyperdense on low-energy monoenergetic images because of the direct relation between the photoelectric effect and the Z value.Given the way iodine behaves on spectral maps, radiologists can optimise the use of contrast media in these CTs, thus allowing lower doses of radiation and lower volumes of contrast media while achieving the same CT values and even enabling lower contrast flow rates, which is especially helpful in patients with poor vascular access. Moreover, in suboptimal diagnostic cases caused by poor contrast opacification, the resolution can be improved, thus avoiding the need to repeat the study.

Local maximum synchrosqueezing adaptive transformation for cross-instantaneous frequencies analysis

Abstract To overcome the shortcomings of existing time-frequency (TF) analysis (TFA) methods in analyzing signals containing cross-instantaneous frequencies (IFs), this paper proposes an adaptive TFA technique combined with image processing methods based on local maximum synchrosqueezing transform. The core idea of the proposed algorithm is to localize the filtering of signals containing several different IF components using kernel functions containing several different directions, respectively, to achieve energy separation at the crossing frequencies. In turn, the local maximum synchrosqueezing transform is used to rearrange the TF energy to the true IF ridges of the signal to improve the TF energy concentration. Simulation data demonstrates that the proposed algorithm has higher energy aggregation and better noise immunity, especially for signals with cross-IFs. Applying the proposed method to animal acoustic and radar wave signals of pedestrians can accurately describe the differences in the frequency change patterns and the temporal distribution of energy in the signals, thereby providing a judgment basis for effectively identifying and classifying the signals.

Valence-band hybridization in sulphides.

The hybridization state in solids often defines the critical chemical and physical properties of a compound. However, it is difficult to spectroscopically detect and evaluate hybridization beyond just general fingerprint signatures. Here, the valence-band hybridization of metal d-derived bands (short: "metal d bands") in selected metal sulphides is studied with a combined spectroscopic and theoretical approach to derive deeper insights into the fundamental nature of such compounds. The valence bands of the studied sulphides are comprised of hybrid bands derived from the metal d, S 3s, and S 3p states. Employing S K and L2,3 X-ray emission spectroscopy and spectra calculations based on density functional theory, the degree of hybridization (i.e., the covalency) of these bands can be directly probed as a function of their relative energies. We find that the relative intensity of the "metal d band" features in the spectra scales with the inverse square of the energy separation to the respective sulfur-derived bands, which can be analytically derived from a simple two-orbital model. This study demonstrates that soft X-ray emission spectroscopy is a powerful tool to study valence state hybridization, in particular in combination with hard X-ray emission spectroscopy, promising a broad impact in many research fields.

System size effects on the free energy landscapes from molecular dynamics of phase-separating bilayers.

The "lipid raft" hypothesis proposes that cell membranes contain distinct domains of varying lipid compositions, where "rafts" of ordered lipids and cholesterol coexist with disordered lipid regions. Experimental and theoretical phase diagrams of model membranes have revealed multiple coexisting phases. Molecular dynamics (MD) simulations can also capture spontaneous phase separation of bilayers. However, these methods merely determine the signof the free energy change upon phase separation-whether or not it is favorable-but not the amplitude. Recently, we developed a workflow to compute the free energy of phase separation from MD simulations using the weighted ensemble method. However, while theoretical treatments generally focus on infinite systems and experimental measurements on mesoscopic to macroscopic systems, MD simulations are comparatively small. Therefore, if we are to put the results of these calculations into the appropriate context, we need to understand the effects the finite size of the simulation has on the computed free energy landscapes. In this study, we investigate this phenomenon by computing free energy profiles for a model phase-separating system as a function of system size, ranging from 324 to 10 110 lipids. The results suggest that, within the limits of statistical uncertainty, bulk-like behavior emerges once the systems contain roughly 4000 lipids.

Jahn-Teller and pseudo-Jahn-Teller effects on the vibronic structure of the photoionized spectrum of cyanopropyne.

Nonadiabatic quantum dynamics are carried out to illustrate the photoionized spectrum of the cyanopropyne (CH3-C≡C-C≡N) as reported in recent experimental measurements [Lamarre et al., J. Mol. Spectrosc. 315, 206 (2015)]. A detailed electronic structure calculation is performed to analyze the topographical details of the first five ionized states, of which three are degenerate states (X̃2E, B̃2E, and C̃2E) and two are non-degenerate states (Ã2A1 and D̃2A1). The degenerate E states of the C3V symmetry molecule are prone to Jahn-Teller (JT) instability, and in addition, symmetry allowed A1 - E vibronic coupling, i.e., pseudo-Jahn-Teller (PJT), effects are expected to have a significant impact in the detailed vibronic structure of these electronic states. The JT splittings of X̃2E and B̃2E degenerate states are small, whereas it is quite large at three high frequencies in the C̃2E electronic states. The large energy separation of X̃2E from the other states and the non-zero PJT coupling of the B̃2E state with the close-lying Ã2A1 state indicate the uncoupled nature of the X̃, Ã, and B̃ vibronic bands of C4H3N. The intersection minima of B̃ and C̃ states with the D̃ state nearly coincide with the energetic minimum of D̃ state. Therefore, the PJT couplings among these states will lead to a strong vibronic interaction to shape the respective band structure. To completely understand the JT and PJT interactions in the photoionized spectrum of C4H3N, the vibronic coupling model Hamiltonian was constructed to perform nuclear dynamics studies for these electronic states. The vibrational progressions in each vibronic band are identified and compared with the available experimental data in the literature. The impacts of JT and PJT effects in the first five ionized states of cyanopropyne are investigated and discussed in detail.

Programmable adhesion through triangular and hierarchical cuts in metamaterial adhesives.

Metamaterial design approaches, which integrate structural elements into material systems, enable the control of uncommon behaviours by decoupling local and global properties. Leveraging this conceptual framework, metamaterial adhesives incorporate nonlinear cut architectures into adhesive films to achieve unique combinations of adhesion capacity, release, and spatial tunability by controlling how cracks propagate forward and in reverse directions during separation. Here, metamaterial adhesive designs are explored with triangular cut features while integrating hierarchical and secondary cut patterns among primary nonlinear cuts. Both cut geometry and secondary cut features tune adhesive force capacity and energy of separation. Importantly, the size and spacing of cut features must be designed around a critical length scale. When secondary cut features are greater than a critical length, cracks can be steered in multiple directions, going both forward and backwards within a primary attachment element. This control over crack dynamics enhances the work of separation by a factor of 1.5, while maintaining the peel force relative to a primary cut. If hierarchical cut features are too small or too compliant, they interact and do not distinctly modify crack behaviour. This work highlights the importance of adhesive length scales and stiffness for crack control and attachment characteristics in adhesive films.This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'.

Numerical investigation of dynamic gas–liquid separator by population balance model

Dynamic gas–liquid separator (DGLS) can efficiently separate gas and liquid phases and are widely used in aerospace, chemical, and petroleum engineering. The energy loss and separation efficiency within the DGLS are studied through the combination of numerical simulations and experiments. Three-dimensional transient Reynolds-Averaged Navier–Stokes equations were solved to analyze the fluid dynamics within the DGLS. The bubble aggregation and breakup in oil were simulated by using the population balance model. Experimental data were meticulously compared with numerical results to validate the accuracy and reliability of the numerical methods. The findings revealed a direct correlation between the inlet flow rate and various performance metrics of the DGLS. Specifically, as the inlet flow rate increased, the energy loss within the DGLS escalated, resulting in higher power consumption. The degassing rate of the DGLS exhibited a decreasing trend with increasing inlet flow rate, while the de-oiling rate showed an inverse relationship. The optimal performance of the separator was observed at an inlet flow rate of 140 m3·d−1, with ηg* and ηl* reaching 0.94 and 0.99, respectively. The relationship between the Qo and the η* and Po was fitted by a second-order polynomial. Moreover, the rotational speed of the DGLS demonstrated a positive correlation with energy consumption, accompanied by an increase in power output. However, the separation efficiency of the DGLS exhibited a non-linear relationship with rotational speed, peaking at a specific value before marginally declining. The optimization of degassing and dewatering rates occurred at a rotational speed of 2500 r·min−1. These findings underscore the importance of carefully adjusting operational parameters to achieve optimal performance and energy efficiency within DGLS.

Vacancy defect and piezoelectric field assisted photocatalytic performance of BiO(Cl1/3Br1/3I1/3)x for the degradation of organic pollutants

Semiconductor photocatalysts have been widely researched in wastewater treatment of organic dyes, among which bismuth halide semiconductors have shown great application prospects due to their unique layered structure and diverse micromorphology. As for photocatalysis, high concentration of photo-generated carriers and their effective separation are considered to be the key to obtain excellent photocatalytic performance. In view of the common issues of high bandgap energy and low carrier separation rate in bismuth halide, in this paper, the BiO(Cl1/3Br1/3I1/3)x catalysts with different proportions of Bi3+ and (Cl1/3Br1/3I1/3)- were designed and synthesized by hydrothermal method, through constructing hybrid energy levels and thus accomplishing by multi-halogen doping to widen the light absorption range. For another, the efficient separation of electrons and holes was achieved in BiO(Cl1/3Br1/3I1/3)x in virtue of a built-in field stemmed from the intrinsic piezoelectric effect, and band tilting. Meanwhile, more active sites were induced by Vo•• and VBiʹʹʹ due to the directional impact of the built-in field. Ultimately, BiO(Cl1/3Br1/3I1/3)5/7 demonstrated the optimum catalytic performance under the combined light irradiation and ultrasonic vibration, with the degradation efficiency of MB reaching 91.28% in 60 min and the k of 0.0360 min-1, and 97.44% degradation efficiency of Rh B within 18 min and the k of 0.1565 min-1 together with excellent cycling stability. The prepared BiO(Cl1/3Br1/3I1/3)5/7 catalyst has a huge application potential for the degradation of wastewater, taking full advantage of environmental vibration energy and light energy.

Shower separation in five dimensions for highly granular calorimeters using machine learning

To achieve state-of-the-art jet energy resolution for Particle Flow, sophisticated energy clustering algorithms must be developed that can fully exploit available information to separate energy deposits from charged and neutral particles. Three published neural network-based shower separation models were applied to simulation and experimental data to measure the performance of the highly granular CALICE Analogue Hadronic Calorimeter (AHCAL) technological prototype in distinguishing the energy deposited by a single charged and single neutral hadron for Particle Flow. The performance of models trained using only standard spatial, energy and charged track position information from an event was compared to models trained using timing information available from AHCAL, which is expected to improve sensitivity to shower development and, therefore, aid in clustering. Both simulation and experimental data were used to train and test the models and their performances were compared. The best-performing neural network achieved significantly superior event reconstruction when timing information was utilised in training for the case where the charged hadron had more energy than the neutral one, motivating temporally sensitive calorimeters. All models under test were observed to tend to allocate energy deposited by the more energetic of the two showers to the less energetic one. Similar shower reconstruction performance was observed for a model trained on simulation and applied to data and a model trained and applied to data.

Substitution of blast furnace slag by melting furnace slag as active component in green concrete application

Blast furnace slag (BFS), a commonly used substitute for cement clinker, is in large demand and gradually increasing in price. Melting furnace slag (MFS), a by-product of the co-disposal of waste incineration fly ash and metallurgical dust sludge, has potential hydration properties, and its large accumulation also poses a serious threat to the environment. In this study, we focus on the effect of MFS replacing BFS on concrete properties and its hydration mechanism. Results showed that MFS significantly enhanced the compressive strength at the later stage of hydration, and the 28-d compressive strength of MSD concrete was 15.15 % higher than BSD concrete. MFS enriched with a large amount of amorphous silica and alumina played a key role in the hydration process. This is mainly shown as the increase in the fluctuation of Si-O and Al-O bond strengths and the decrease in the energy separation between Ca 2p and Si 2p levels. In addition, the increased substitution of aluminum for silicon in MSD results in the formation of C-A-S-H gels, which are tightly bonded with ettringite to form a composite structure. Subsequent durability assessments indicate that the incorporation of MFS diminishes the permeability to chlorides and sulfates, while also bolstering the concrete’s resistance to carbonation. These findings imply a positive impact on the concrete’s enduring service life.

Inner Side Chain Modification of Small Molecule Acceptors Enables Lower Energy Loss and High Efficiency of Organic Solar Cells Processed with Non-halogenated Solvents.

Organic solar cells (OSCs) processed with non-halogenated solvents usually suffer from excessive self-aggregation of small molecule acceptors (SMAs), severe phase separation and higher energy loss (Eloss), leading to reduced open-circuit voltage (Voc) and power conversion efficiency (PCE). Here, we designed and synthesized two SMAs L8-PhF and L8-PhMe by introducing different substituents (fluorine for L8-PhF and methyl for L8-PhMe) on the phenyl end group of inner side chains of L8-Ph, and investigated the effect of the substituents on the intermolecular interaction of SMAs, Eloss and performance of OSCs processed with non-halogenated solvents. It is found that compared with L8-PhF, which possesses strong intermolecular interactions but downgraded molecular packing order, L8-PhMe exhibits more effective non-covalent interactions, which improves the tightness and order of molecular packing. When blending the SMAs with PM6, the OSCs based on L8-PhMe shows reduced non-radiative energy loss, and enhanced Voc than the devices based on the other two SMAs. Consequently, the L8-PhMe based device processed with o-xylene and using 2PACz as the hole transport layer shows an outstanding PCE of 19.27%. This study highlights that the Eloss of OSCs processed with non-halogenated solvents could be decreased through regulating the intermolecular interactions of SMAs by inner side chain modification.

High-efficiency microplastic removal in water treatment based on short flow control of hydrocyclone: Mechanism and performance

Microplastics have been identified as a potentially emerging threat to water environment and human health. Therefore, there is a pressing demand for effective strategies to remove microplastics from water. Hydrocyclone offers a rapid separation and low energy consumption alternative but require reduction of microparticle entrainment by short flow, which limits the effectiveness for small density differentials and ultralow concentrations separation. We proposed an enhanced mini-hydrocyclone with overflow microchannels (0.72 mm width) based on the active control of short flow in hydrocyclone for microplastic removal from water. The overflow microchannels effectively redirect the particles that would typically be entrained by the short flow, leading to higher separation efficiency. Simulation results show overflow microchannels effectively reduced short flow to 0.7 %, a reduction of up to 94 % compared to conventional hydrocyclones. The hydrocyclone with overflow microchannel demonstrated a removal efficiency exceeding 98 % for 8 μm plastic microbeads at ultralow concentrations (10 ppm), which is a 33.7 % improvement over conventional hydrocyclone. Compared with other methods (e.g., filtration, adsorption, coagulation) for microplastic removal, this work achieves rapid separation capability and long period operation, highlighting hydrocyclone as a promising approach for microplastic removal in industry-scale water treatment.

Mirror corrections in predictions of nucleon separation energies for nuclei near the proton drip line

Mirror corrections in predictions of nucleon separation energies for nuclei near the proton drip line

Extraction of sustainable and low-emission hydrogen from hydrogen-blended natural gas driven by multi-product sequential separation

Blending hydrogen in natural gas, taking advantage of the readily available pipeline transportation, is considered as a highly promising means of sustainable hydrogen deployment on a vast scale. However, re-obtaining hydrogen from the mixture for end users via conventional separation technologies could pose practical challenges both energetically and economically, due primarily to the relatively low blending ratio (<30 vol%). In contrast to the commonly adopted pressure swing adsorption (PSA) separation, we propose a thermochemical approach of deriving hydrogen with synergistic capture of CO2 by steam reforming of the mixture to tackle such challenges. The process is simulated by a two-dimensional model validated by experimental data. Three typical scenarios with hydrogen blending ratios of 0–30 vol% are investigated in the operating temperature range of 300–400 °C and natural gas pipeline pressure of ≤ 40 bar. Results show that in all scenarios the amount of hydrogen recovered can exceed the amount of renewable hydrogen initially blended and additional hydrogen could be contributed thermochemically, all at relatively low energy cost. Thermochemical methods increase the partial pressure of target products, reducing separation energy and increasing yield. For the typical 10 vol% blending ratio (widely adopted), when considering the separation of hydrogen at the end user and compressing the separated off-gas before transporting it to the next end user, the hydrogen separation cost, after counterbalancing with the revenue from carbon dioxide, is only 1.33$/kgH2 with the new approach. This corresponds to a decrease by over 70.2 % as compared with that of the PSA separation cost (4.45$/kgH2). The captured CO2 in its high-purity form helps to reduce the final cost of hydrogen by a maximum of 0.33$/kgH2. The new route shows great potential for integrated hydrogen production, hydrogen purification and carbon capture for the promotion of renewable energy, green hydrogen and related technologies.

Investigation of the sustainable production of ethylene oxide by electrochemical conversion: Techno-economic assessment and CO2 emissions

Ethylene oxide (EO) is a pivotal intermediate in the chemical industry owing to its versatility and high demand. Currently, direct oxidation is the most important technical process to produce EO. This conventional process, in which ethylene is partially oxidized with air or oxygen, has limited selectivity for EO of 65–90%, leading to significant CO2 emissions. This study explores an alternative method involving the electrochemical selective oxidation of ethylene powered by renewable electricity. The electrochemical oxidation technology is expected to reduce CO2 emitted during EO production. Process models were developed based on existing literature data. A techno-economic evaluation and sensitivity analysis focusing on the electrochemical cell variables were conducted. In this assessment, the investment and production costs of the electro-oxidation process for EO production were compared with those of the conventional process. This assessment also compared processes producing of mono-ethylene glycol and ethylene carbonate from EO. These analyses reveal that the separation energy has a significant impact on the carbon footprint. While current economic and environmental benefits are not favorable, this study identifies key descriptors of the technology for further reducing the carbon footprint. Based on the evaluation results, this study demonstrates the potential to cut CO2 emissions in half compared to conventional plants by utilizing the electro-oxidation of ethylene via a direct route.

Ab initio study of Z(N) = 6 magicity* *This work is partially supported by the National Natural Science Foundation of China (Grant Nos. 12175280, 12250610193, 12375143, 11975282, 11705240, 11435014), the Natural Science Foundation of Gansu Province, China (Grant Nos. 20JR10RA067, 23JRRA675), the Chinese Academy of Sciences "Light of West China" Program, the Key Research Program of the Chinese Academy of

The existence of magic numbers of protons and neutrons in nuclei is essential for understanding the nuclear structure and fundamental nuclear forces. Over decades, researchers have conducted theoretical and experimental studies on a new magic number, Z(N)=6, focusing on observables such as radii, binding energy, electromagnetic transition, and nucleon separation energies. We performed ab initio no-core shell model calculations for the occupation numbers of the lowest single particle states in the ground states of Z(N)=6 and Z(N)=8 isotopes (isotones). The results of our calculations do not support Z(N)=6 as a magic number over a range of atomic numbers. However, 14C and 14O exhibit the characteristics of double-magic nuclei.