Mass Transfer Kinetics Research Articles

Mercury removal from aqueous media by aminated polyacrylonitrile beads impregnated with nano-urchin bismuth sulfide particles: Experimental and theoretical analysis under batch and continuous mode

The present study encompasses a thorough analysis of aqueous Hg (II) adsorption using aminated polyacrylonitrile beads incorporated with high-capacity surfactant assisted bismuth sulfide nanoparticles. The porous beads provided effective contact between aqueous Hg and the inorganic nano-adsorbent (PBS2) that was encapsulated in the matrix. The macro-sized beads served as suitable packing material for designing a fixed bed adsorption column for continuous mode analysis without significant pressure build up and offered an easy solid–liquid separation after treatment. A marginal negative zeta potential of the adsorbent beads improved the interaction with Hg2+ facilitating the sorption. The incorporation of amine groups into the polymeric bead surface via amination increased the adsorption capacity further from 83.30 mg/g to 130.00 mg/g (∼56.00%) at 303 K. The associated parameters of batch kinetics (effective pore diffusivity and mass transfer coefficient) were determined using a first principle-based model available in literature. Mercury was chemisorbed via synergistic lone pair interactions of S and N atoms with Hg, leading to formation of coordination bonds (Hg-S and Hg-N). An established mass transfer model was utilized to generate simulated breakthrough curves for the continuous analysis using synthetic feed. Additionally, the adsorption column showed comparable performance using both synthetic and real water samples (synthetically spiked) maintaining high selectivity. The optimized values of axial dispersion coefficient (Ez) and fixed bed mass transfer coefficient (kfb) were estimated and subsequently used for the scale up studies to predict column life. The adsorbent beads were regenerated using 0.05 M EDTA aqueous solution and showed good reusability (>95.00%) after 5 cycles of operation. Overall, this work highlights a reusable Hg adsorbent possessing good selectivity and capacity and simultaneously demonstrating real-field applicability.

Numerical study of thermal and concentration transport in Sisko ternary-nanofluid

The study of the behavior of generalized Newtonian fluid flows and heat transfer has practical implications. In this study, attention is paid to examining the dynamics of flow, heat, and mass transfer in a siskofluid containing multi-nanoparticles. The governing partial differential equations can be turned into ordinary differential equations using the transformations. FEM numerical scheme is used for the solutions of problems. A free study is performed, and the validity of the results is given. The solutions, that are convergent and mesh-free, are used to explore the facts regarding heat and mass. Both shear-thinning and shear-thickening fluids experience less skin friction as the material parameter is increased. The wall heat transfer rate in ternary nanofluids has the highest value in comparison with that in hybrid and mono nanofluids. Similarly, the wall mass flux in the case of ternary nanofluid is the highest in comparison with that in hybrid and mono nanofluid.

Characterization of freeze-dried ginger slices with carboxymethyl cellulose as potential coating material prior to osmotic dehydration

Edible coating prior to osmotic dehydration has been studied extensively to enhance the performance of drying in food products. In this study, the effectiveness of carboxymethyl cellulose (CMC) coating before osmotic dehydration of ginger slices on the mass transfer was studied. The samples were then dried using a freeze dryer, and the changes in colour, structural, and chemical components were determined. Coated ginger showed a minimised solute gain without affecting the water loss performance. The mass transfer kinetics were fitted successfully using the Magee model. After the freeze-drying process, the combination of CMC and osmotic dehydration as a pre-treatment influenced the colour properties and the microstructure without altering the functional groups. From these findings, it shows that CMC coated ginger slices and osmotic dehydration prior to freezedrying can be an alternative to meet the demands of current consumers, and thus be a promising route for obtaining dried ginger.

An Engineering Method of Analyzing the Dynamics of Mass Transfer during Concrete Corrosion Processes in Offshore Structures.

The environment of an underground structure is much more complex than the above-ground environment. Erosion processes are underway in soil and groundwater; groundwater seepage and soil pressure are also typical for underground environments. Alternating layers of dry and wet soil have a strong effect on concrete, and they reduce its durability. Corrosion of cement concretes is caused by the diffusion of free calcium hydroxide, located in the pores of concrete, from the volume of the cement stone to its surface, bordering on an aggressive environment, and the further transition of the substance through the phase boundary solid (concrete)-soil-aggressive environment (liquid). Due to the fact that all minerals in cement stone exist only in saturated or close-to-saturated solutions of calcium hydroxide, a decrease in the content of which in the pores of concrete as a result of mass transfer processes causes a change in the phase and thermodynamic equilibrium in the body of concrete and leads to the decomposition of highly basic compounds of cement stone and, consequently, to the deterioration of the mechanical properties of concrete (reduction in strength, modulus of elasticity, etc.). A mathematical model of mass transfer in a two-layer plate imitating the "reinforced concrete structure-layer of the soil-coastal marine area" system is proposed as a system of nonstationary partial derivative differential equations of the parabolic type with Newmann's boundary conditions inside the building and at the interface between the soil and the marine environment and with conjugating boundary conditions at the interface between the concrete and the soil. When the boundary problem of mass conductivity in the "concrete-soil" system is solved, expressions are obtained to determine the dynamics of the concentration profiles of the target component (calcium ions) in the volumes of the concrete and soil. As a result, one can select the optimum composition of concrete, having high anticorrosion properties, to extend the durability of the concrete constructions of offshore marine structures.

Tannic Acid-Mediated Layered Double Hydroxide Hybridizing PVDF Superwetting Catalytic Membranes Constructed via Ion Diffusion-Induced Interfacial Self-Assembly for Boosting Water Purification

It is a great challenge to fabricate superwetting catalytic membranes with intrinsic self-cleaning capacity for highly stable and effective water purification by simple, mild and energy-efficient manufacturing technologies. Herein, diffusion-induced interfacial self-assembly and polyphenol-mediated strengthening strategies were employed to fabricate tannic acid -mediated layered double hydroxide hybridizing PVDF superwetting catalytic membranes (named as TA@CoFe-LDH@PVDF). The simultaneous phase transformation/in-situ synthesis of CoFe-LDH nanosheets and subsequent coordination assembly with tannic acid (TA) was implemented. Superhydrophilic and underwater-superoleophobic properties were achieved through the cooperation effect of the rough microstructures of CoFe-LDH nanosheets and the strong hydration ability of TA molecules. This enabled efficient separation of various oil-in-water emulsions with more than 99 % separation efficiency and permeation flux up to 593.9 L m-2h−1 bar−1 in cross-flow filtration. Furthermore, due to the reducibility of TA molecules that promoted the Mn+1/Mn+ cycle, TA@CoFe-LDH@PVDF membrane exhibited high static degradation efficiency and kinetics (nearly 100 % in 5.0 min) toward methylene blue by PMS activation. The degradation rate constant (1.04 min−1) was 2.67 times compared to that of CoFe-LDH@PVDF. Surprisingly, it was found that the dynamic mass transfer process in the membrane significantly accelerated the catalytic kinetics, resulting in a degradation rate in dead-end filtration was 23.89 times higher than that under static conditions. Additionally, it was proved that assembled TA could inhibit and reduce metal ion leaching during the catalytic and separation process. This simple manufacturing process of multifunctional membranes with superior performances offers a high application potential in wastewater treatment.

3D-Printed Hydrodynamic Focusing Lab-on-a-Chip Device for Impedance Flow Particle Analysis

Particles analysis, such as cell counting and differentiation, are widely used for the diagnosis and monitoring of several medical conditions, such as during inflammation. Three-dimensional-printed lab-on-a-chip (LOC) devices, which can utilize one of the cell counting methods, can bring this technology to remote locations through its cost-efficient advantages and easy handling. We present a three-dimensional-printed LOC device with integrated electrodes. To overcome the limited resolution of a 3D printer, we utilized a flow-focusing design. We modeled and simulated the mass transfer and flow dynamics in the LOC by incorporating a flow-focusing design and reached an optimal channel diameter of 0.5 mm, resulting in a flow-focusing distance of <60 µm. We also used electrochemical impedance spectroscopy to enable the dependence of the electrode–solution interface on the flow-focusing properties. Finally, we highlighted the proof-of-concept detection of microspheres (6 µm diameter), which model biological cells that flow in the channel, by recording the electrochemical impedance at 10 kHz, thus showing the potential of a future point-of-care (POC) device.

Hydrophobic dual metal silicate nanotubes for higher alcohol synthesis

Herein, a hydrophobic CuCoSNTs-c catalyst with hollow tubular structure and mesoporous wall was synthesized successfully for higher alcohol synthesis (HAS). The tubular CuCoSNTs-c was constructed with elaborately designed hydrophobic and aerophilic properties to suppress the formation of C1 molecules and enhance the CO conversion and C2+OH selectivity. The mesoporous wall exposed the active sites sufficiently, and the macroscopic tubular channel improved the mass transfer kinetics and accelerated the desorption of alcohol products. Moreover, the hydrophobic and aerophilic tube wall could modulate the local microenvironment of CuCoSNTs-c, that is, enriching the H2 and CO molecules around the CuCo active sites and rapidly desorbing the in-situ produced water molecules in HAS. The hydrophobic multifunctional CuCoSNTs-c catalyst suppressed the selectivity of CO2 to less than 1.2%, while achieving a C2+OH selectivity of up to 66.6% at a CO conversion of 80.4%. This catalyst demonstrated excellent stability for 360 h without obvious activity loss.

Specific Ion Effect on the “Water Bridge” Interaction at an Interface: A New Understanding into the Extraction and Separation Selectivity Based upon Competitive Diffusion and Adsorption

Understanding the essence of a specific ion effect on the intermolecular interaction at the near-interface boundary layer during solvent extraction is crucial for developing new approaches to achieve enhanced extraction and separation of various valuable metals from complex aqueous solutions. The present work aims to detect the microscopic effect from competitive diffusion and adsorption of various salt cations in the near-interface boundary layer on their interaction with amphiphilic model molecules, 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (P507), at the air–water interface by using the Langmuir–Blodgett (LB) monolayer technique. It was found that the interaction between cations and P507 molecules through a long-range hydrogen bond “water bridge” confined in the near-interface boundary layer plays a crucial role in determining the difference in the diffusion mass transfer rate of ions with different hydration abilities. Conventional understanding about competitive extraction of various metal cations controlled mainly by their thermodynamic difference in the interaction intensity with the P–O and P═O groups in P507 molecules cannot explain such a kind of specific ion effect on the mass transfer kinetics via ion hydration. Molecular dynamics simulation revealed that the hydration ability of ions is the key factor determining the mass transfer rate and interaction intensity. In the low salt concentration region, the interaction intensity of salt cations with the P–O and P═O groups in P507 molecules is one of the determinants of the competitive adsorption behavior at the interface. However, in a higher salt concentration region, the specific ion salting-out effect via ion hydration becomes significant, causing a decrease in hydration of the target salt cation; therefore, it dominated the diffusion mass transfer rate of ions. This work provides a new insight to understand the kinetic role of competitive diffusion and adsorption of ions in the near-interface boundary layer and their effect on extraction and separation selectivity. It lays the foundation for achieving controllable separation of target metal ions by adjusting the coexisting ion species and their concentrations.

Effects of channel wall wettability on gas–liquid dynamics mass transfer under Taylor flow in a serpentine microchannel

The wall wettability of microchannels plays an important role in the gas–liquid mass transfer dynamics under Taylor flow. In this study, we regulated the contact angle of the wall surface through surface chemical grafting polymerization under controlled experimental conditions. The dynamic changes of CO2 bubbles flowing along the microchannel were captured by a high-speed video camera mounted on a stereo microscope, whilst a unit cell model was employed to theoretically investigate the gas–liquid mass transfer dynamics. We quantitatively characterized the effects of wall wettability, specifically the contact angle, on the formation mechanism of gas bubbles and mass transfer process experimentally. The results revealed that the gas bubble velocity, the overall volumetric liquid phase mass transfer coefficients (kLa), and the specific interfacial area (a) all increased with the increase of the contact angle. Conversely, gas bubble length and leakage flow decreased. Furthermore, we proposed a new modified model to predict the gas–liquid two-phase mass transfer performance, based on van Baten's and Yao's models. Our proposed model was observed to agree reasonably well with experimental observations.

Catalytic CO2 Capture via Ultrasonically Activating Dually Functionalized Carbon Nanotubes.

High energy consumption and high cost have been the obstacles for large-scale deployment of all state-of-the-art CO2 capture technologies. Finding a transformational way to improve mass transfer and reaction kinetics of the CO2 capture process is timely for reducing carbon footprints. In this work, commercial single-walled carbon nanotubes (CNTs) were activated with nitric acid and urea under ultrasonication and hydrothermal methods, respectively, to prepare N-doped CNTs with the functional group of -COOH, which possesses both basic and acid functionalities. The chemically modified CNTs with a concentration of 300 ppm universally catalyze both CO2 sorption and desorption of the CO2 capture process. The increases in the desorption rate achieved with the chemically modified CNTs can reach as high as 503% compared to that of the sorbent without the catalyst. A chemical mechanism underlying the catalytic CO2 capture is proposed based on the experimental results and further confirmed by density functional theory computations.

Ion exchange resin – Bipolar membrane electrodialysis hybrid process for reverse osmosis permeate remineralization: Cation exchange resins equilibria and kinetics

Reverse osmosis (RO) membrane technology is widely used for producing high-quality drinking water. Yet RO permeate is by itself acidic (pH = 5.5 to 6.0), unbuffered and has low mineral content, therefore post treatment i.e., remineralization is mostly required. An ion exchange resin – bipolar membrane electrodialysis hybrid process was developed for sustainable RO permeate remineralization. Fundamental phenomena in the recovery of calcium and magnesium by ion exchange to remineralize reverse osmosis permeate were investigated. Sorption equilibrium and mass transfer kinetics were investigated for weakly acidic (Amberlite IRC747, Amberlite IRC748, Lewatit S8227) and strongly acidic (DOWEX Marathon MSC) cation exchange resins. Most suitable resin for the remineralization process should have high selectivity for calcium and magnesium and low selectivity for monovalent ions to avoid adding undesired ions to the remineralised water downstream as well as relatively fast mass transfer kinetics. The isotherms were correlated with the stoichiometric ion exchange isotherm and the Langmuir-Freundlich (Sips) isotherm. All resins showed high selectivity for ions with higher valence, but weakly acidic cation exchange (WAC) resins showed significantly lower selectivity towards monovalent ions than the strongly acidic cation exchange resin. The influence of each resin functional group, charge density and degree of protonation was shown to have a major effect on the resin selectivity. Amberlite IRC748 had the lowest selectivity (KNH4+/Na+ = 0.77 ± 0.19) and removal (46%) for ammonium in a single-component system. The mass transfer rate was found to be controlled by intraparticle diffusion rather than film diffusion. Amberlite IRC748 is recommended for use in a remineralization process where divalent ions are present because of its favourable sorption and higher mass transfer kinetics (Ks = 8.65 ± 0.58 × 10−12, 7.95 ± 0.38 × 10−12 m2/s for calcium and magnesium, respectively).

Mass transfer dynamics of single CO2 bubbles rising in monoethanolamine solutions: Experimental study and mathematical model

Carbon dioxide (CO2) absorption into amine-based absorbents is a widely used method for carbon emission reduction to deal with global warming problems. The intensification of the absorption process relies on an in-depth understanding of the mass transfer mechanisms between CO2 gas and the reaction media. However, the influence of products of a chemical reaction on mass transfer dynamics is usually underestimated. In this study, we perform research studies on the absorption process of single CO2 bubbles rising in monoethanolamine (MEA) solutions. Firstly, we perform an experimental study to visualize and measure the spatial position and the diameter of the bubbles using the high-speed camera. We observe a special phenomenon that the CO2 bubble diameter rapidly decreases to a nearly constant value in MEA solutions, and the terminal bubble diameter increases with the MEA concentration. Based on the phenomenon, we divide the absorption process into two stages. One is the mass transfer enhancement stage, where the bubble diameter decreases rapidly. The other is the mass transfer deterioration stage, where the bubble diameter remains almost constant. Furthermore, we propose an elaborate mass transfer dynamics model considering the combined effect of chemical reaction kinetics and reaction-induced bubble surface contamination. Finally, a well-predictive performance by the mass transfer dynamics model is validated by experiment. The findings of this study are of theoretical and practical significance for the mass transfer in gas–liquid reactive flow and multiphase reactor design.

Comprehensive analysis of lithium-ion cells and their aging trajectory toward nonlinear aging

More than 30 years after the market introduction of lithium-ion batteries, research still struggles to understand the complex interplay of different aging mechanisms that can lead to a sudden drop in usable capacity. Understanding this nonlinear aging behavior is important to develop optimal strategies regarding the cell design and operation. In this work, we present an extensive analysis of a cycle aging test comprising 62 commercial large-scale pouch-bag type cells in a constant force bracing. The dataset includes eight cells, which exhibit nonlinear aging. Nondestructive methods, such as differential voltage analysis, reveal that the capacity loss is limited by the loss of lithium inventory, which is not homogeneous within the cell . With destructive post-mortem analysis we observe that aging is focused toward the center of the anode. Occurring lithium-plating seems to intensify with aging at high temperatures. Our results point toward a two-step mechanism, where elevated temperatures drive SEI-growth at the electrodes’ center, which, in turn, impair mass transfer kinetics and lead to the deposition of metallic lithium. Ultimately, our work can help to identify the most relevant mechanisms and interactions that provoke nonlinear aging.

Targeted Energy Delivery and Heat-Mass Transfer Processes in Systems with Nano-, Micro-, and Macroelements

Introduction. The production of modern technologies should take into account a comprehensive analysis of energy, biotechnological and thermophysical phenomena. The main processes in food technologies are the processes of heat and mass transfer, which need to be intensified. Aim of the Article. The aim of the work is studying the mechanisms and modeling the kinetics of heat and mass transfer in the microware field in the technologies for complex processing of food raw materials. Materials and Methods. The combination of thermal, hydrodynamic and diffusion driving forces with their coordinated action is able to solve problematic issues of processing raw materials, primarily food. Using the principles of the similarity theory, there is proposed a dimensionless complex – the number of energy action, which reflects the influence of the electromagnetic field. Results. Direct, targeted energy supply to the liquid phase of raw materials makes it possible to obtain a solid phase in the apparatus. These are fundamentally new features for the dehydration process. Boil-off rates at constant electromagnetic field intensity depend only on the solvent type. As a result of processing all experimental points, a criterion equation was obtained, it establishes the dependence of the energy action number on the dimensionless pressure and the dimensionless heat of the phase transition. Discussion and Conclusion. There are developed a new class of heat and mass exchange equipment ‒ electrodynamic apparatuses. The experimental results suggest that the flow from capillaries and nano-capillaries is initiated much faster when organizing the processes of targeted energy delivery with the involvement of pulsed microware field. An important advantage of electrodynamic extractors is the possibility of obtaining polyextracts. Food technologies with targeted energy delivery during evaporating, drying and extracting are resource- and energy-efficient and ensure full preservation of raw material potential.

Pulsed electric field using the needle–needle electrodes for improving the salt diffusion of pork brine salting

Pulsed electric field (PEF), as an emerging nonthermal processing technology, has attracted extensive attention and research in food processing. In the present study, PEF has been approved that has the potential to enhance salt diffusion in pork. In this study, pork lions were pretreated with PEF before being immersed in the brine (5% NaCl [w/w]) at 4°C to investigate the effect of needle-needle PEF pretreatment on pork brine salting. The changes in the weight, moisture, and salt content were detected during the salting process. The effective diffusion coefficient (De) and mass transfer kinetics were calculated.Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were subsequently used to analyze the microstructure of the pork and the secondary structure of myofibrillar proteins (MPs). The outcomes demonstrated that after brining for 8h with PEFpretreatment, the weight, moisture, and salt changes increased significantly. The central salt content achieved by 12h brining after PEF treatment (4.5kV) is equivalent to that achieved by brining for 20h without any treatment. The De was raised to 4.0×10-10 (PEF) from 3.1×10-10 (control).SEM and FTIR results revealed that PEF altered the microstructure of pork and the secondary structure of MP.Our study demonstrated that PEF generated by needle-needle electrodes could effectively promote salt diffusion and shorten salting processing.

Simulation Study of Xylitol-Mediated Effect on NaCl Diffusion Behavior in Cured Pork Tenderloin.

Polyhydroxy alcohol-mediated curing has great potential for producing low-salt cured meat products. This study investigated the mass transfer kinetics and the one-way diffusion simulation of sodium chloride (NaCl) during the curing process. Furthermore, Fick's second law determined the NaCl diffusion coefficient (De) of xylitol-mediated cured pork tenderloin. The results demonstrated that adding xylitol could reduce the De of NaCl. The De of NaCl, calculated using the one-way model, was 1.29 × 10-9 m2·s-1, 1.22 × 10-9 m2·s-1, 1.2 × 10-9 m2·s-1, and 1.15 × 10-9 m2·s-1 when the amount of xylitol added was 0%, 4%, 8%, and 12% (w/w), respectively. This result agrees with the predicted values from the power function time-varying model. Moreover, a three-dimensional simulating model of mass transfers constructed using COMSOL Multiphysics was developed to evaluate the NaCl diffusion in pork tenderloin during the curing process. This model has high accuracy and can be used to describe the diffusion of NaCl in curing. Overall, this study provided a foundation for NaCl diffusion and distribution during the curing process.

Unusual hcp Ni with metal and non-metal dual doping modulation to realize boosted urea oxidation

Modulating cost-competitive metallic Ni-based electrocatalysts with favorable surface electronic configuration to boost urea oxidation reaction (UOR) is crucial to urea-related technologies, yet dauntingly challenging due to limited tailoring methods. Herein we put forward a novel N-doping induced phase transfer strategy to construct anomalous metastable hcp Ni with metal Co and non-metal N dual doping engineering (hcp-CoNi-N/C) for manipulating electronic state and catalytic response toward the UOR. Impressively, the hcp-CoNi-N/C can deliver prominent UOR performance with an exceptionally low potential of 1.310 V vs. RHE to attain 10 mA cm−2 and fast reaction kinetics (34.0 mV dec–1), standing out among the best UOR catalysts reported to date. The combined experimental analysis and theoretical calculations disclose that unconventional hcp phase design coupled with metal and non-metal dual doping engineering enables electron density manipulation and creates a charge-polarized surface favorable for urea adsorption and C–N bond cleavage, thereby substantially promoting urea decomposition. Meanwhile, such synergistic phase and doping engineering can boost mass transfer kinetics via tailoring the wetting characteristics. This study offers a new paradigm to craft advanced metallic Ni-based UOR catalysts through unusual metastable phase design synergistic with multiple doping engineering.

Isobutanol to isobutene: Processes and catalysts

The present review aims at summarizing the scientific literature data and patents concerning the isobutanol, preferably from a fermentation process, selective dehydration reaction to produce isobutene (isobutylene). The benefits and drawbacks of the conditions used on the process design and catalyst performances are illustrated, analyzed and discussed with much objectivity. Thermodynamic equilibria of the various reactants and products are provided together with the limiting step rate. Isobutanol selective dehydration to isobutene can be done under low or high pressure conditions. This choice impacts not only the downstream recovery and purification of isobutene, but also the stability of the catalyst and the reactor volume. Due to the strong inhibition of the alumina catalysts by steam, the reaction under pressure requires longer contact times and catalyst volume. The alumina catalysts need to have a good hydrothermal stability to avoid a rapid deactivation. Isobutene purification is also addressed. The impact of the water partial pressure on the catalytic dehydration is described and shown to affect the side reactions. Mass transfer limitations and kinetics of the reaction are well documented. Relevant advices are provided to perform the reaction without undesired products.

Gas–Liquid Transport Behaviors and Mass Transfer Mechanism During Oxygen Dissolution and Evolution Processes in a Micropump

Abstract On-orbit refueling and space circulation technologies involve the use of a space micropump to transport gas–liquid mixed fluids, which affects the gas–liquid mass transfer and dynamic behaviors. To predict dynamic mass transfer processes, our proposed dissolved and released models were applied to space micropump calculation after the verification of dissolved oxygen concentration and micropump energy characteristics. The mass transfer characteristics and gas–liquid states were investigated by combining the correlation analyses. The results show that the dissolved concentration and the volume fraction are considered to be strongly related to the mass transfer rate, and the effect of turbulence kinetic energy cannot be ignored particularly in the impeller and volute. Based on this, the gas–liquid state parameters are focused on unidirectional dissolved and bidirectional released-dissolved conditions. The released gas occupied the head of the suction surface of the long blades and developed downstream, and its presence causes a significant gas increase downstream. According to the mass-transfer characteristics comparisons, the oxygen increment decreases as the inlet dissolved oxygen concentration increases, exhibiting the similarity of the two-film theory. In addition, the evolution increases the fluctuation in the gas volume fraction and the total hydraulic loss. The current study guides the fueling gas–liquid mixed delivery status, and the dissolved gas concentration must be controlled strictly to avoid the evolution of gas to ensure safety and decrease the flow loss.

CFD Modelling of Gas-Solid Reactions: Analysis of Iron and Manganese Oxides Reduction with Hydrogen

Metallurgical processes are characterized by a complex interplay of heat and mass transfer, momentum transfer, and reaction kinetics, and these interactions play a crucial role in reactor performance. Integrating chemistry and transport results in stiff and non-linear equations and longer time and length scales, which ultimately leads to a high computational expense. The current study employs the OpenFOAM solver based on a fictitious domain method to analyze gas-solid reactions in a porous medium using hydrogen as a reducing agent. The reduction of oxides with hydrogen involves the hierarchical phenomena that influence the reaction rates at various temporal and spatial scales; thus, multi-scale models are needed to bridge the length scale from micro-scale to macro-scale accurately. As a first step towards developing such capabilities, the current study analyses OpenFOAM reacting flow methods in cases related to hydrogen reduction of iron and manganese oxides. Since reduction of the oxides of interest with hydrogen requires significant modifications to the current industrial processes, this model can aid in the design and optimization. The model was verified against experimental data and the dynamic features of the porous medium observed as the reaction progresses is well captured by the model.