Development Of Advanced Processes Research Articles

Constructing a 3D ordered macroporous cobalt monoatomic catalyst for efficient SMX degradation via PMS activation

The cobalt monoatomic catalyst with 3D ordered macropores structure (3DOM Co/NC) was prepared using the crystalline porous material ZIF-67 and SiO2 as the precursor and template, and used to investigate the effect of its activation with peroxymonosulfate (PMS) on sulfamethoxazole (SMX) removal. The mesoporous structure mostly retained after ZIF-67 carbonisation, and the formation of new homogeneous macropores after the removal of the SiO2 template, which greatly increases the surface area of the catalyst (429 m2 g-1) and promotes long-range mass transfer. Additionally, Co monoatomic sites were formed in the porous skeleton, providing electrons that were utilised for the activation of PMS. This distinctive structure enables it to almost completely degrade of 20 ppm SMX within 3min and show excellent catalytic degradation efficiency in a wide pH range (3.0-9.0) and high-salinity simulated wastewater (10-100mM). In addition, the main ROS in the catalytic degradation process were explored as 1O2 and O•2-. Combined with the results of DFT calculations and product analyses, the active sites of SMX were predicted and the degradation pathways and mechanisms were inferred, confirming that the degradation process of SMX poses a low risk of toxicity to the environment. This study reveals that the addition of 3DOM Co/NC was more favourable for the activation of PMS for SMX degradation, which contributes to the development and improvement of advanced oxidation processes for environmental remediation.

Electrochemical Methods for Nutrient Removal in Wastewater: A Review of Advanced Electrode Materials, Processes, and Applications

In response to the increasing global water demand and the pressing environmental challenges posed by climate change, the development of advanced wastewater treatment processes has become essential. This study introduces novel electrochemical technologies and examines the scalability of industrial-scale electrooxidation (EO) methods for wastewater treatment, focusing on simplifying processes and reducing operational costs. Focusing on the effective removal of key nutrients, specifically nitrogen and phosphorus, from wastewater, this review highlights recent advancements in electrode materials and innovative designs, such as high-performance metal oxides and carbon-based electrodes, that enhance efficiency and sustainability. Additionally, a comprehensive discussion covers a range of electrochemical methods, including electrocoagulation and electrooxidation, each evaluated for their effectiveness in nutrient removal. Unlike previous studies, this review not only examines nutrient removal efficiency, but also assesses the industrial applicability of these technologies through case studies, demonstrating their potential in municipal and industrial wastewater contexts. By advancing durable and cost-effective electrode materials, this study emphasizes the potential of electrochemical wastewater treatment technologies to address global water quality issues and promote environmental sustainability. Future research directions are identified with a focus on overcoming current limitations, such as high operational costs and electrode degradation, and positioning electrochemical treatment as a promising solution for sustainable water resource management on a larger scale.

Attention Based Energy Demand Forecasting in Smart Grid Environments

The smart grid is a crucial aspect of the modern energy landscape, providing a reliable, efficient, and sustainable way of meeting the growing energy demands. However, the vast amounts of data generated by smart grid technology necessitate the development of advanced data processing and analysis techniques. In this paper, we propose an attention-based time series workflow that combines dilated convolution and attention mechanisms for time series forecasting in smart grid applications. This workflow extracts temporal features from time series data using dilated convolutions and emphasizes significant temporal points in the hidden states using attention mechanisms. Experimental evaluations showed up to an 8% better performance for energy demand forecasting compared to commonly used deep learning-based methods. Our workflow achieved this gain by requiring 1/3 of the training time other models took. We also improved performance by 42% in various domains, demonstrating the adaptability of our approach across different areas. This study may assist researchers in constructing accurate forecasting models for smart grid environments. Furthermore, it highlights that the attention-based approach can be employed to promote sustainable energy and optimize smart grid environments.

Electrochemical generation of H*-•OH redox pair for rapid removal of refractory nitro-organic micropollutants

This study developed an innovative reduction-oxidation coupling process for treatment of refractory organic wastewater. We constructed a series of N5-coordinated transition metals (TMs) (TMs = Mn, Fe, Co, Ni, Cu) single-atom sites supported on nitrogen-rich carbon nitride (SA-TM-C3N5) for electrochemical generation of the surface-adsorbed hydrogen atom (H*) and hydroxyl radical (•OH). The SA-Co-C3N5 exhibited the highest activity for production of the H*-•OH redox pair, which effectively degraded refractory nitro-organic micropollutants via the parallel reduction-oxidation pathways. The SA-Co-C3N5-mediated electro-Fenton-like system showed high removal efficiency (99 %) and mineralization capacity (78 %) toward metronidazole (MNZ) with low energy consumption (0.019 kWh (g TOC)–1). The trifunctional properties of the H* have contributed to the reduction of nitro compounds, the 2e– ORR for H2O2 production and the Fenton-like catalysis for •OH generation. This work sheds lights on the development of advanced reduction-oxidation coupling process for green and sustainable water purification.

Explore synergistic catalytic ozonation by dual active sites of oxygen vacancies and defects in MgO/biochar for atrazine degradation

The design of highly efficient and sustainable catalytic materials is highly desirable for the development of advanced oxidation process (AOPs) used in water treatment. This study used waste litchi shells as precursors to prepare biochar (BC). The composite material (BC@MgO) was synthesized upon loading magnesium oxide (MgO) on BC and used for the heterogeneous catalytic ozonation (HCO) of atrazine (ATZ). BC@MgO exhibited an ATZ degradation rate of 92.8 % over 30 min under the optimal degradation conditions and maintained its good catalytic performance over four cycles, exhibiting excellent catalytic activity and stability. Characterization and experimental results revealed the synergistic effect of oxygen vacancies (OVs) and BC defects on the adsorption and decomposition of ozone molecules. The exposure of the surface magnesium ions was promoted in the presence of OVs on MgO, allowing water molecules to dissociate on the surface magnesium sites to form surface hydrated hydroxyl groups. Biochar defects accelerated the adsorption of ozone molecules by virtue of its higher surface energy. These active sites led to the substantial generation of reactive oxygen species (ROS), which possessed strong oxidizing ability and thereby participated in the degradation of ATZ. In addition, the possible degradation pathways and toxicity of ATZ were evaluated. Overall, this design provided a novel approach to the comprehensive utilization of waste lychee shells, as well as an efficient, stable, and green catalyst for the development of AOPs used in water treatment.

UV-activated calcium peroxide system enables simultaneous organophosphorus degradation, phosphate recovery, and carbon fixation

Advanced oxidation processes are a desirable technology for treatment of contaminants of emerging concern. Nevertheless, conventional advanced oxidation of organophosphorus compounds releases inorganic phosphate, posing downstream concerns related to eutrophication. For this reason, we evaluated the ultraviolet light-activated calcium peroxide (UV/CaO2) system for effective treatment of organophosphorus compounds and concurrent capture of the mineralization products, phosphate. The degradation mechanisms, reaction kinetics, and mineralizations were assessed to determine the overall efficiency and performance of the UV/CaO2 process. Knowledge gaps related to photocatalysis in the UV/CaO2 system were not only addressed, but also leveraged to identify unique advantages for removal of organophosphorus compounds and their degradation products. Experimental results confirmed that the UV/CaO2 system effectively mineralized organophosphorus compounds and recovered inorganic phosphate; additionally, collaborative carbon fixation performance of the system reveals the potential of carbon utilization. These outcomes were facilitated by the alkaline environment generated by CaO2. The recovered solids contained most of the phosphorus and carbon from the parent compounds. Ultimately, these findings provide transformative, new insights into the development and application of advanced oxidation processes that prevent downstream concerns related to mineralization products, especially inorganic phosphorus and carbon.

Biogenic Synthesis Based on Cuprous Oxide Nanoparticles Using Eucalyptus globulus Extracts and Its Effectiveness for Removal of Recalcitrant Compounds

Recalcitrant compounds resulting from anthropogenic activity are a significant environmental challenge, necessitating the development of advanced oxidation processes (AOPs) for effective remediation. This study explores the synthesis of cuprous oxide nanoparticles on cellulose-based paper (Cu2O@CBP) using Eucalyptus globulus leaf extracts, leveraging green synthesis techniques. The scanning electron microscopy (SEM) analysis found the average particle size 64.90 ± 16.76 nm, X-ray diffraction (XRD) and Raman spectroscopy confirm the Cu2O structure in nanoparticles; Fourier-transform infrared spectroscopy (FTIR) suggests the reducing role of phenolic compounds; and ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis DRS) allowed us to determine the band gap (2.73 eV), the energies of the valence band (2.19 eV), and the conduction band (−0.54 eV) of Cu2O@CBP. The synthesized Cu2O catalysts demonstrated efficient degradation of methylene blue (MB) used as a model as recalcitrant compounds under LED-driven visible light photocatalysis and heterogeneous Fenton-like reactions with hydrogen peroxide (H2O2) using the degradation percentage and the first-order apparent degradation rate constant (kapp). The degradation efficiency of MB was pH-dependent, with neutral pH favoring photocatalysis (kapp = 0.00718 min−1) due to enhanced hydroxyl (·OH) and superoxide radical (O2·−) production, while acidic pH conditions improved Fenton-like reaction efficiency (kapp = 0.00812 min−1) via ·OH. The reusability of the photocatalysts was also evaluated, showing a decline in performance for Fenton-like reactions at acidic pH about 22.76% after five cycles, while for photocatalysis at neutral pH decline about 11.44% after five cycles. This research provides valuable insights into the catalytic mechanisms and supports the potential of eco-friendly Cu2O nanoparticles for sustainable wastewater treatment applications.

A novel combination of wetland plants (Eichhornia crassipes) and biochar derived from palm kernel shells modified with melamine for the removal of paraquat from aqueous medium: a green and sustainable approach

Herbicide contamination in aquatic systems has become a global concern due to their long- term persistence, accumulation and health risks to humans. Paraquat, a widely used and cost-effective nonselective herbicide, is frequently applied in agricultural fields for pest control. Consequently, the removal of paraquat from contaminated water is crucial. This research presents a sustainable and environmentally benign method for paraquat removal from aqueous system by integrating wetland plants (Eichhornia crassipes) with biochar derived from melamine-modified palm kernel shells. The prepared biochar was characterized by using various analytical techniques. The effectiveness of biochar in enhancing phytoremediation was evaluated through a series of experiments, showing significant paraquat removal efficiencies of 99.7, 98.3, and 82.8% at different paraquat concentrations 50, 100, and 150 mg L−1, respectively. Additionally, present study examined the impact of biochar on the growth of E. crassipes, highlighting its potential to reduce the toxic effects of paraquat even present at higher concentrations. The paraquat removal mechanism was elucidated, focusing on the synergistic role of biochar adsorption and phytoremediation capability of E. crassipes. This innovative approach is an effective, feasible, sustainable and eco-friendly technique that can contribute to the development of advanced and affordable water remediation processes for widespread application.

A Change from Negative to Positive of Later Adoption Using the Innovation Decision Process to Imply Sustainability for HR Chatbots of Private Companies in Thailand

The current adoption of human resource (HR) chatbots has created problems within organizations, such as stilted conversational flow and a limited range of queries and responses. This paper presents an analysis of the factors affecting these issues by employing a new conceptual model. The instances of rejection and acceptance of an HR chatbot were analyzed in this study using the innovation decision process. A survey of 251 employees from private companies in Thailand was conducted, scrutinizing their experiences of using HR chatbots. Then, the innovation decision process was utilized to identify the critical factors that influenced the shift in attitude from rejection to acceptance. The survey identified three key findings affecting employees’ negative attitudes towards the HR chatbot, namely, hesitation concerning the perceived ease-of-use (HPEOU), word of mouth (WoM), and personal innovation (PI). Additionally, our research also revealed that the way people perceive the level of risk associated with using the HR chatbot directly affects their intention to reject. This highlighted the significance of organizational development for facilitating the re-engagement of employees with the HR chatbot, and specifically, a focus on the elements of people (PP), processes (PC), technology (TE), and policy (PL). This study demonstrated the advances in process development within an organization and its corresponding policies. The validation of HR chatbots was influenced by a distinct corporate vision. This study provides guidelines for the implementation of HR chatbots for employees in private corporations in Thailand. The findings can assist in enhancing operational performance and the subsequent adoption of HR chatbots, resulting in the sustainable development of an efficient acceptance evaluation model of change from negative to positive. This model uses the innovation decision process to foster the sustainability of HR chatbots in private companies in Thailand.

Insight into the sulfite activation by Fe-rich sludge-derived biochar for efficient organic contaminant degradation: The role of iron species

Sulfate radical-based advanced oxidation processes driven by sulfite [S(IV)] activation offer a sustainable and cost-effective approach for environmental remediation. The utilization of abundant iron oxide species in Fe-rich sludge for S(IV) activation presents a cost-effective and eco-friendly solution, making it an attractive option for Fe-rich sludge disposal and water treatment. Herein, an efficient S(IV) activation system was developed by using Fe-rich sludge-derived biochar (FBC) for the first time. The performance of S(IV) activation by different pyrolyzed FBCs was evaluated in terms of tetracycline (TC) degradation. The highest degradation efficiency of TC was achieved 95.0 % in the S(IV)/FBC700 under the optimum conditions. The reactive radical species responsible for TC degradation in the system were confirmed to be SO4•−. The present work opens up new possibilities for the development of novel advanced oxidation processes utilizing the waste Fe-rich sludge.

Recent advances in robust and ultra‐thin Li metal anode

AbstractLi metal batteries have been widely expected to break the energy‐density limits of current Li‐ion batteries, showing impressive prospects for the next‐generation electrochemical energy storage system. Although much progress has been achieved in stabilizing the Li metal anode, the current Li electrode still lacks efficiency and safety. Moreover, a practical Li metal battery requires a thickness‐controllable Li electrode to maximally balance the energy density and stability. However, due to the stickiness and fragile nature of Li metal, manufacturing Li ingot into thin electrodes from conventional approaches has historically remained challenging, limiting the sufficient utilization of energy density in Li metal batteries. Aiming at the practical application of Li metal anode, the current issues and their initiation mechanism are comprehensively summarized from the stability and processability perspectives. Recent advances in robust and ultra‐thin Li metal anode are outlined from methodology innovation to provide an overall insight. Finally, challenges and prospective developments regarding this burgeoning field are critically discussed to afford future outlooks. With the development of advanced processing and modification technology, we are optimistic that a truly great leap will be achieved in the foreseeable future toward the industrial application of Li metal batteries.

Effects of homogenization and deep cryogenic treatments on microstructure and mechanical property of D2 tool steel fabricated by laser direct energy deposition

The integration of laser direct energy deposition (L-DED) for manufacturing high-hardness D2 tool steel components presents a promising avenue for addressing the increasing complexity of product geometries demanded by modern industry. However, the inherent variability in microstructure and mechanical properties induced by L-DED across the build height necessitates the employment of post-processing techniques to achieve material homogeneity. This study explores the synergistic application of homogenization and deep cryogenic treatment (DCT) as a novel post-processing strategy aimed at mitigating microstructural inhomogeneities and enhancing the mechanical properties of L-DED-fabricated D2 tool steel. Initial analysis of the as-built samples revealed a microstructure characterized by a fine network of eutectic carbides enveloping an FCC matrix, which imposed constraints on martensite transformation during DCT. Homogenization was found to effectively alleviate these constraints, promoting compositional and microstructural uniformity and enabling a more consistent transformation to martensite across the samples upon subsequent DCT. The strategic combination of homogenization and DCT resulted in achieving uniformly distributed high hardness levels exceeding 750 HV throughout the entire sample, regardless of their initial positions within the build. This study demonstrates the potential of combining homogenization with DCT as an effective approach to enhance the structural integrity and mechanical performance of L-DED-fabricated D2 tool steel, offering valuable insights for the development of advanced manufacturing processes for alloyed materials.

Boosting peroxymonosulfate activation over partial Zn-substituted Co3O4 for florfenicol degradation: Insights into catalytic performance, degradation mechanism and routes

Florfenicol (FLO) is a broad-spectrum halogenated antibiotic (containing F and Cl atoms), and the discharged FLO in wastewater exhibits potential biotoxicity. Peroxymonosulfate (PMS) activation can generate reactive oxygen species (ROSs) to realize efficient degradation of organic pollutants. Herein, Zn-substituted Co3O4 (ZnxCo) catalysts were prepared and applied in PMS activation for FLO degradation. The physicochemical properties were systematically studied by combining experiments and density functional theory (DFT) calculation. The Zn partial substitution induced electron rearrangement and promoted oxygen vacancy (OV) formation in Co3O4. Zn0.03Co catalyst exhibited superior FLO removal, achieving a higher reaction rate of 0.112 min−1 than Co3O4 (0.053 min−1). The FLO degradation was highly dependent on the factors of PMS/Zn0.03Co/FLO dosage, temperature, initial pH, and coexisting inorganic anions. The Zn0.03Co also displayed outstanding performance in PMS activation for degradation of various typical organic pollutants. Electron paramagnetic resonance (EPR) spectra and quenching experiments indicated that both radical species (·OH, SO4·-, and ·O2-) and nonradical species (1O2) contribute to FLO removal. The redox cycle of Co3+/Co2+ and OVs played an essential role in PMS activation. The electron structure of FLO and parameters of PMS adsorbed on ZnxCo were calculated. The longer length of CoO and OO bonds for the adsorbed PMS could enhance its activation to generate ROSs. The intermediates were detected, and five degradation pathways were proposed. The acute and chronic toxicities of intermediates suggested that the dechlorination process is important for the toxicity attenuation of FLO. This study clarified the performance enhancement mechanism of Zn substitution on FLO degradation by PMS activation using Co3O4 based catalyst, which favors the development of PMS-based advanced oxidation processes for wastewater treatment.

Understanding the pivotal role of ubiquitous Yellow River suspend sediment in efficiently degrading metronidazole pollutants in water environments

Sulfite-based advanced oxidation technology has received considerable attention for its application in organic pollutants elimination. However, the potential of natural sediments as effective catalysts for sulfite activation has been overlooked. This study investigates a novel process utilizing suspended sediment/sulfite (SS/S(IV)) for degradation of metronidazole (MNZ). Our results demonstrate that MNZ degradation efficiency can reach to 93.1 % within 90 min with 12.0 g SS and 2.0 mM sulfite. The influencing environmental factors, including initial pH, SS dosage, S(IV) concentration, temperature, and co-existing substances were systematically investigated. Quenching experiments and electron paramagnetic resonance analyses results indicate that SO3•− is the primary active substance responsible for MNZ degradation, with involvement of SO4•−, SO5•−, and •OH. X-ray photoelectron spectroscopy and Mössbauer spectra reveal that Fe (III)-silicates play a crucial role in activating S(IV). Furthermore, analysis of degradation intermediates and pathways of MNZ is conducted using liquid chromatography with mass spectrometry (LC -MS). The toxicity of MNZ and its intermediates were also systematically evaluated by the T.E.ST. program and wheat seeds germination test. This study offers valuable insight into the activation of sulfite by natural sediments and could contribute to the development of SS-based advanced oxidation processes (AOPs) for the in-situ remediation of antibiotics-contaminated water environments.

Enhanced tensile strength of TiAl/Ti2AlNb diffusion bonding joint by a novel post-bonded hot deformation

Dissimilar TiAl-based alloys weld by solid-state bonding, also known as diffusion bonding (DB), usually show brittle intermetallic compounds, high interfacial stress, and poor properties. A novel post-bonded process strategy, slight deformation in the direction of stress parallel to the bonding interface, was developed in the post-bonded treatment of the TiAl/Ti2AlNb joint. The effect of post-bonded processes on the interfacial microstructure, element diffusion, fracture characteristics and mechanical properties were systematically investigated. The results showed that the post-bonded hot deformation (PBHD), compared to the traditional post-bonded heat treatment (PBHT), can effectively increase the major elements diffuse and the growth of the reaction layer, as well as promote the precipitates which distribute uniformly in the reaction layer, finally resulting in superior tensile strength. Compared with the DB samples, the ultimate tensile strength of the PBHD joint increased by 45.58%. In addition, the fracture behavior was further analyzed based on the microfracture morphology and crack propagation path. These findings will facilitate the development of advanced manufacturing processes of blisk for high-temperature light alloys.

An assessment of the role of geophysics in future U.S. geologic carbon storage projects

Geologic carbon storage (GCS) is ramping up worldwide as a viable component of carbon capture, utilization, and storage (CCUS) projects aimed at reducing greenhouse pollution to limit climate change. GCS may be a growth opportunity for the application of geophysics in reservoir characterization and monitoring. Federal and state government financial incentives are the economic motivators of the CCUS business in the United States, and recent increases in these incentives have triggered a large number of U.S. Environmental Protection Agency Class VI permit applications to inject CO2 for GCS. The applications indicate that almost all such projects propose using geophysical technology for monitoring. We assessed the GCS geophysical market in the United States based on an intensive analysis of recently filed Class VI permit applications. The analysis shows that reprocessing of existing seismic data will be the primary geophysical activity for reservoir characterization prior to CO2 injection. For monitoring, verification, and recording of CO2 injection, time-lapse vertical seismic profiling and 3D seismic imaging will be the dominant technologies followed by 2D time-lapse seismic imaging and some nonseismic methods. Passive seismic monitoring is planned for the majority of CCUS projects to reduce the risk of induced seismicity. If assumptions related to the United States meeting its current climate goals by 2050 are met, then geophysical activity will increase over the next 30 years. An estimate of the seismic crew count needed to support the projects suggests that the scale of GCS-related seismic acquisition by 2050 may reach the current level of onshore oil and gas geophysics crews in the United States. While the economic incentives of a regulation-driven market will press for the minimization of geophysical sensing in GCS, there is also the potential for growth in geophysical activity with the development of advanced processing and analysis tools, multiphysics data interpretation, and cost-effective continuous monitoring.

Light-driven ammonia synthesis under mild conditions using lithium hydride.

Photon-driven chemical processes are usually mediated by oxides, nitrides and sulfides whose photo-conversion efficiency is limited by charge carrier recombination. Here we show that lithium hydride undergoes photolysis upon ultraviolet illumination to yield long-lived photon-generated electrons residing in hydrogen vacancies, known as F centres. We demonstrate that photon-driven dehydrogenation and dark rehydrogenation over lithium hydride can be fulfilled reversibly at room temperature, which is about 600 K lower than the corresponding thermal process. As light-driven F centre generation could provide an alternative approach to charge carrier separation to favour chemical transformations that are kinetically or thermodynamically challenging, we show that light-activated lithium hydride cleaves the N≡N triple bond to form a N-H bond under mild conditions. Co-feeding a N2/H2 mixture with low H2 partial pressure leads to photocatalytic ammonia formation at near ambient conditions. This work provides insights into the development of advanced materials and processes for light harvesting and conversion.

Dark and sunlight-driven dye degradation over a TiO2–dibenzoylmethane hybrid xerogel

The pursuit of sustainable and inexpensive systems for the degradation of organic aquatic pollutants working under sunlight or even without irradiation is still open. Herein, an amorphous titanium oxide modified with dibenzoylmethane, an aromatic diketone, is proposed as a solar photocatalyst showing oxidative activity also in the dark. Ti(IV)-dibenzoylmethanate (dbm) complexes form during the sol-gel synthesis and are dispersed throughout the oxide gel structure. This ligand-to-metal charge transfer complex plays a dual role: it enables visible light absorption, narrowing the apparent band gap, and provides localized surface charge, promoting the spontaneous formation and stabilization of superoxide radical ions by reduction of O2. The activity of the TiO2-dbm hybrid was assessed in the removal of methylene blue from aqueous solution. The results demonstrated a rather stable photocatalytic activity under natural sunlight, exceeding 80% dye removal after 1 h in four subsequent tests, a value that was mostly recovered after a mild regeneration. Considerable efficiencies were also achieved in the dark, owing to the immobilized superoxide radicals acting as initiators of degradation pathways. Finally, the influence of the operating conditions (pH, illumination, mixing method, water contact) on the efficiency and durability of the performances was evaluated to survey the long-term utilization in water decontamination. The behaviour of this hybrid material resembles a “photocatalytic memory” effect and may widen the perspectives for the development of heterogeneous advanced oxidation processes.

The effect of size and shape of annular centrifugal contactors upon hydrodynamics and mass transfer using HNO3-TBP/OK

Annular centrifugal contactors (ACCs) are process intensification equipment for liquid-liquid extraction (also known as solvent extraction) that use centrifugal force that 200x greater than traditional gravity settling (Baker et al., 2022a). The size and throughput of ACCs have been denoted by their increasing rotor diameter (RD), from 10 mm up to 1330 mm. In this work a multiscale ACC platform has been commissioned, (consisting of 10, 25, 40 mm RD ACCs), to collect the physical liquid-holdup and mass transfer across several sizes to inform future computation modelling flowsheets of liquid-liquid extraction (LLE).Experimental studies have been performed with nitric acid with tributyl phosphate in odourless kerosene (TBP/OK) relevant to the development of advanced PUREX processes for recovery of actinides from spent fuel. Hydrodynamic trials determined the minimum Relative Centrifugal Force (RCF) required to separate extreme solvent/aqueous (S/A) feed ratios and total throughputs across the three sizes of ACC. The novel 'stepped stop' method has provided understanding of the actual liquid holdups within the two distinctly different regions (mixing annulus and separating rotor) ACC during operation to provide accurate residence times. These values were subsequently used to calculate the mass transfer and stage efficiency of aqueous nitric acid with tributyl phosphate in odourless kerosene. The smallest contactor was determined to be distinct and likely under-predicting performance of larger contactors. Ultimately the geometry and the aspect ratio supersedes using rotor diameter for defining scale-up of annular centrifugal contactors.

FEATURES OF NATURAL GAS DEMETHANIZATION PROCESS

Today, a significant part of the raw materials used in industry consists of natural gas. Thus, an important and urgent task for the further development of the industry is the development of more advanced processes aimed at natural gas treatment and processing of. Low temperature processes in gas processing are widespread due to the increasing demand for individual hydrocarbons and the growing demand for liquefied gases. Low temperature distillation remains the most important method for separating gas mixtures, especially when high throughput is required. The demethanization process is an industrially important example of such a process, which involves the interaction of separation, cooling and heat recovery systems.This article discusses a number of basic methods for low-temperature gas separation, such as condensation, rectification, absorption and separation, as well as the features of their application. Low-temperature separation is carried out in two stages in column-type apparatuses, the first of which demethanization is carried out with methane and C2+ fractions release. An overview of the demethanization process currently used for natural gas refining is given, and the key features of the demethanizer operation are described. The technological design of the process of low-temperature distillation, the design features of the installations are considered, a typical scheme of the demethanization process is given. Various technological schemes of demethanization proposed in patents are analyzed. A comparative analysis of the use of tray and packed contact devices and criteria for choosing a mass transfer column apparatus are given. The demethanization column arrangement is shown, the internal devices of the column, the feed input system, as well as the method of supplying heat to the demethanizer are described.