Secondary Liquid Phase Research Articles

Oiling-Out: Insights from Gibbsian Surface Thermodynamics by Stability Analysis.

The crystallization process is a significant stage in the pharmaceutical industry. During the process of crystallization with cooling, it is possible for a secondary liquid phase to appear before the formation of crystals. This phenomenon is called "oiling out" or liquid-liquid phase separation (LLPS). In this article, we explore the oiling-out phenomenon in a binary system of water and vanillin using stability analysis based on Gibbsian surface thermodynamics. To obtain the full picture of oiling out, we investigated three cases: droplet-solute-lean liquid equilibrium (DLE), crystal-solute-rich liquid equilibrium (CL'E), and crystal-solute-lean liquid equilibrium (CLE). The phase diagram of the system is plotted using the NRTL model for activity coefficients, along with considering the effect of the interfacial curvature on the phase diagram. From the phase boundaries and free-energy diagram of each case, we showed that the occurrence of the oiling-out phenomenon is justified based on the lower energy barrier of the droplet formation compared to that of the crystal formation. However, the energy level of a stable crystal is significantly lower and hence more stable than that of a stable droplet. Finally, we have determined different regions for droplet and crystal formation in the metastable phase diagram based on their supersaturation and provide insight for the oiling-out phenomenon.

Two-stage reaction rates in transesterification of palm oil with methanol catalysed by anion-exchange resin with tetrahydrofuran as a co-solvent

Several heterogeneous catalysts have been proposed as recoverable catalysts for transesterification in place of homogeneous hydroxide or methoxide. Anion-exchange resin is a potential recoverable and reusable catalyst but its industrial use is still barred by its low catalytic activity. Transesterification of refined palm oil with methanol catalysed by anion-exchange resin was studied. A phenomenon limiting the reaction rates was discovered and is presented. Two types of anion-exchange resins were used as the catalysts: dense IRA402 and macroporous A26. With IRA402, an oil conversion of only 6.1 % was obtained from 4 h transesterification at 60 °C with a methanol-to-oil molar ratio of 9.5:1 and 4 cm3 resin per 42 cm3 reaction mixture. Severe mass transfer resistance in this three-phase system appeared to be the limiting factor. Addition of tetrahydrofuran (THF) as a co-solvent helped form a single liquid phase. The oil conversion was improved to 19.3 %. The reaction between oil and adsorbed methoxide at resin’s ion-exchange sites seemed to be the rate-determining step. When A26 was used, the rate of FAME production was boosted due to the porous nature of the resin. Nevertheless, the reaction rate fell sharply after a while into a slower second stage. The formation of a secondary liquid phae in resin pores triggered by glycerol generation was proposed as the cause of this drop in the reaction rate. A higher oil conversion of 63.4 % was obtained. Diluting the reaction mixture with more THF eliminated the slower second stage and sustained the firststage’s faster reaction rate. An oil conversion of 84.7 % was achieved from 3 h transesterification. A finite-volume model was developed to simulate the reaction and internal mass transport in A26 resin beads. The proposed secondary liquid phase formation and a branching pore structure in resin beads were required in the model to reproduce experimental data. The findings suggested improvement directions for anion-exchange resin as a catalyst for transesterification.

Deformation behavior of heterogeneous lamellar Cu-Fe-P immiscible alloys with enhanced strength and ductility produced by laser powder bed fusion

Cu-Fe-P immiscible alloys characterized by heterogeneous lamellar structure were manufactured by laser powder bed fusion (LPBF) and the deformation behavior of LPBF-produced immiscible alloys was investigated systematically. When the linear energy density of 133 J/m is adopted during LPBF, the immiscible alloy exhibits the highest compressive strength (∼1 GPa) and engineering strain (∼27%). The high strength of the LPBF-produced immiscible alloy is attributed to the heterogeneous lamellar structure including the interconnected Fe2P layer and nano-Fe2P particles as “hard” phase dispersed in the ε-Cu matrix as the “soft” phase. Moreover, the good ductility is attributed to the fine ε-Cu grains as “soft” phase precipitated within the lamellar Fe2P due to the secondary liquid phase separation (SLPS). This “soft-hard-soft” heterogeneous microstructure can effectively delay crack growth to exhibit excellent mechanical properties in the LPBF-produced immiscible alloys.

Electric Field‐Induced Microstructural Evolution in Polycrystalline Bi2O3‐Doped ZnO in Presence of a Secondary Liquid Phase

Herein, a spectrum of electric field–induced microstructural evolution phenomena are observed in polycrystalline Bi2O3‐doped ZnO, and the underlying mechanisms are revealed. An applied electric field can drive the migration of bismuth (Bi) toward the negative electrode (including the motion of the charge‐neutral Bi‐rich liquid phase via electrochemical coupling), which produces a Bi‐free zone near the anode. The field‐induced migration of Bi creates a junction between electron‐conducting ZnO and ion‐conducting Bi2O3‐doped ZnO (via Bi2O3‐enriched liquid‐like intergranular films [IGFs]), where an oxygen ion current is converted to an electron current while generating O2 gas, generating a porosity belt. Aberration‐corrected electron microscopy further reveals the formation of three distinct types of grain boundaries (GBs). “Clean” ZnO GBs are observed near the anode, where Bi is depleted by the electric field. Bi2O3‐enriched liquid‐like IGFs (disordered GBs) are observed in the middle section. Near the cathode, electrochemical reduction induces an GB disorder–order transition to form fast‐moving Bi2O3‐enriched ordered GBs, which causes abnormal grain growth. Herein, several new field–matter interaction phenomena are discovered and an exemplar of field effects on microstructural evolution are established at multiple length scales in the presence of GB complexion (phase‐like) transitions.

Multiple ultrasounds assisted phase separation and monotectic solidification of liquid ternary Al81.5Cu14.7Bi3.8 immiscible alloy

Multiple power ultrasounds were employed to investigate the phase transition process of ternary Al81.5Cu14.7Bi3.8 immiscible alloy by various exerting modes. As the ultrasonic sources increased, the liquid phase separation pattern transformed from (Bi)-rich layered macrosegregation into the uniform distribution of secondary (Bi) droplets. Meanwhile, the primary (Al) phase evolved from coarse dendrites into plenty of small spherical grains and also tended to be uniformly dispersed. The subsequently formed ternary (Al) + (Al2Cu) + (Bi) monotectic structure, featured by the alternative (Al) and (Al2Cu) lamellar structure with fine (Bi) grains distributed, was coarsened first and then refined. Numerical simulations showed that the transient cavitation and the acoustic streaming strength were significantly enhanced by increasing ultrasonic beams, with the fourfold ultrasounds producing the most prominent effects on the phase separation process. The intensive and enlarged cavitation areas greatly accelerated the nucleation of both the secondary liquid phase and primary solid phase, which refined the growing (Bi) droplets and (Al) dendrites. The strength and morphology of acoustic streaming were the key factors in offsetting Stokes motion and carrying the growing grains to various regions, resulting in a uniform microstructure. Furthermore, increasing ultrasonic sources improved the friction and wear properties of the solidified alloy, which indicated that the Al81.5Cu14.7Bi3.8 immiscible alloy may become an excellent wear-resistant material owing to the uniform monotectic structure fabricated by the fourfold ultrasounds.

Enhanced adsorption performance of La(III) and Y(III) on kaolinite by oxalic acid intercalation expansion method

This paper reported a new method to enhance adsorption performance of La(III) and Y(III) on kaolinite by enlarging the interlayer space of kaolinite. The intercalation method could enlarge the interlayer space of kaolinite effectively in previous research literatures, whereas there were few studies on utilizing further reaction of intercalators to expand and exfoliate kaolinite by generating gas. The expanded kaolinite (EKH) involved in this study could enhance adsorption performance of La(III) and Y(III) significantly. The EKH in a state between extended and exfoliated was obtained undergoing two steps. Firstly, H2C2O4 was inserted into the kaolinite layers through the secondary substitution liquid phase intercalation method. Secondly, the Kaol-H2C2O4 (KH) intercalation complex was rapidly calcined with H2C2O4 and Na2CO3, the power provided by the neutralization reaction promoted the thermal decomposition of H2C2O4 between the kaolinite layers to produce a large amount of gas. XRD showed that the interlayer space of the KH intercalation complex expanded from 0.717 nm to 1.112 nm. The specific surface area and total pore volume of the EKH were 1.5 and 2.2 times higher than unmodified kaolinite respectively. The surface of EKH possessed higher zeta potential with more negative charges. The results of batch adsorption experiments showed that the adsorption capacity (101.5 mg/g and 78.9 mg/g) of EKH to La(III) and Y(III) was much higher than that of kaolinite (17.1 mg/g and 9.8 mg/g). Pseudo-second-order model and Langmuir model manifest the adsorption kinetics and isotherm. Therefore, the EKH prepared by the intercalation expansion method could be prospectively applied to the treatment of La(III) and Y(III) in industrial wastewater.

Microstructure and properties of Y2O3/Cu composites fabricated by a novel liquid phase in situ reactive synthesis process

Cu–Y2O3 composites were prepared by a secondary mechanical ball milling process and liquid phase in situ reaction and then sintered by the spark plasma sintering (SPS) consolidation technique. The microstructure and mechanical properties were studied using an X-ray powder diffractometer, scanning electron microscope, tensile tester, and Vickers hardness tester. The results showed that the added yttrium was converted into Y2O3, and the obtained Y2O3 nano-particles were uniformly distributed in the copper matrix, their mean size was 5.0 nm, and the cubic Y2O3 phase was coherent with the copper matrix, which indicated (422)Y2O3// (1‾11) Cu and [011‾] Y2O3// [11‾2] Cu orientation relationship. With the addition of Y, the mechanical properties of the composite materials were improved, and the hardness of 10 vol% Y2O3 was increased by 192.0%. Its tensile strength increased by 168.2% compared to pure copper.

Comparison of Atmospheric Monocarboxylic and Dicarboxylic Acids in Xi’ an, China, for Source Apportionment of Organic Aerosols

To investigate the characteristic distributions and formation mechanism of the polar organic components in atmospheric aerosols, atmospheric particulates were simultaneously sampled at three typical sites in urban(U), suburban(S) and rural(R) of Xi’an in summer and winter. Organic compositions, including dicarboxylic acids (DCAs), monocarboxylic acids (MCAs) were emphatically analyzed to explore the seasonal, spatial, and other variations. The results showed that total concentrations of DCAs and MCAs in winter were higher than those in summer. Athough the total content of DCAs in PM10 in winter is lower than that of MCAs, the total concentration of DCAs in PM2.5 and PM10 in summer are higher than that of MCAs. The total concentration of DCAs in PM2.5 in winter and summer were 1878 ± 1425 ng/m3 and 1334 ± 493 ng/m3, 1294 ± 943 ng/m3 and 728 ± 477 ng/m3 in PM10. While the total concentration of MCAs in PM2.5 in winter and summer were 1193 ± 1142 ng/m3 and 541 ± 367 ng/m3, 1659 ± 1162 ng/m3 and 492 ± 424 ng/m3 in PM10. Urban subtotal concentrations of DCAs from PM2.5 were the highest, and mass of organic acids in sunny days were significantly lower than the hazy days. Strong correlations were observed among the DCAs with ambient oxidants and precursors. Moreover, DCAs concentrations were vulnerable to the environmental factors, such as light intensity and relative humidity. Comparisons demonstrated that MCAs mainly comes from coal combustion, vehicle exhaust and other primary emissions, while the secondary photochemistry and liquid phase oxidation are the main sources of DCAs.

Microstructure and properties of homogeneous Cu90Fe10 immiscible composites with nanotwins by laser powder deposition: Effect of spot size

To select the reasonable spot size during laser powder deposition (LPD), the homogeneous Cu90Fe10 immiscible composites were produced by LPD with different spot sizes (2 mm and 4 mm in diameter). The LPD-produced Cu90Fe10 immiscible composites deposited with different spot sizes display a similar microstructure composed of α-Fe/γ-Fe and ε-Cu phases. A large amount of nanoscale Fe-rich particles is uniformly embedded within the Cu-rich matrix and the Cu-rich particles with nanotwins are distributed within the Fe-rich particles due to secondary liquid phase separation (SLPS). Moreover, some nanoscale FeCr grains (∼20 nm) are precipitated within the Fe-rich particles. Both the averaged diameter and grain size of Fe-rich particles reduce with decreasing the spot size due to higher cooling rate. The immiscible composite produced with spot size of 2 mm exhibits higher microhardness and elastic modulus (1.9 GPa and 143.5 GPa respectively) than the corresponding ones for the counterpart with spot size of 4 mm (1.8 GPa and 142.6 GPa respectively) and Brass. As a result, the LPD-produced Cu90Fe10 immiscible composite deposited with spot size of 2 mm exhibits higher wear and corrosion resistance compared to that deposited with spot size of 4 mm.

Automated System for Small-Population Single-Particle Processing Enabled by Exclusive Liquid Repellency.

Exclusive liquid repellency (ELR) describes an extreme wettability phenomenon in which a liquid phase droplet is completely repelled from a solid phase when exposed to a secondary immiscible liquid phase. Earlier, we developed a multi-liquid-phase open microfluidic (or underoil) system based on ELR to facilitate rare-cell culture and single-cell processing. The ELR system can allow for the handling of small volumes of liquid droplets with ultra-low sample loss and biofouling, which makes it an attractive platform for biological applications that require lossless manipulation of rare cellular samples (especially for a limited sample size in the range of a few hundred to a few thousand cells). Here, we report an automated platform using ELR microdrops for single-particle (or single-cell) isolation, identification, and retrieval. This was accomplished via the combined use of a robotic liquid handler, an automated microscopic imaging system, and real-time image-processing software for single-particle identification. The automated ELR technique enables rapid, hands-free, and robust isolation of microdrop-encapsulated rare cellular samples.

Resíduo de mármore como atenuador de efluente ácido

Dimension stones are worldwide used as building and finishing material, reason why the environmental problems inherent to this productive sector became relevant in various countries. One of these problems is the production of large amounts of wastes during the sawing of rocky blocks and polishing of plates. The waste generated by cutting marble with diamond wire consists of fine particles of calcium and magnesium carbonate dispersed in water. This mud has basic character, and it is destined to drying beds or open pit deposits. In parallel, many production processes generate hazardous acidic effluents, which disposal is a serious and global problem. The pH of these solutions must be neutralized or, at least, raised to levels that are considered safe by environmental regulations. In this work, a strong acid solution was treated with varying amounts of marble waste coming from the dimension stone industry. The treatment generated secondary solid and liquid phases that were analyzed to determine the feasibility of their disposal in landfills. The waste raised the pH of the acid solution from near 1.0 to values between 5.0 and 6.0, which are acceptable levels for non-dangerous effluents. Besides that, loss of up to 50% in mass occurred, diminishing the amount of the primary solid waste. By the other hand, the levels of total dissolved solids (TDS), Cu, chlorides and nitrates on the liquid phase of the effluent remained higher than that allowed by environmental legislation for discharge into water bodies. Nevertheless, their characteristics correspond to non-hazardous and non-inert wastes, which, after dried, can be discarded in ordinary waste landfills.

Capillary Structured Suspensions from In Situ Hydrophobized Calcium Carbonate Particles Suspended in a Polar Liquid Media.

We demonstrate that capillary suspensions can be formed from hydrophilic calcium carbonate particles suspended in a polar continuous media and connected by capillary bridges formed of minute amounts of an immiscible secondary liquid phase. This was achieved in two different polar continuous phases, water and glycerol, and three different oils, oleic acid, isopropyl myristate, and peppermint oil as a secondary liquid phase. The capillary structuring of the suspension was made possible through local in situ hydrophobization of the calcium carbonate particles dispersed in the polar media by adding very small amounts of oleic acid to the secondary liquid phase. We observed a strong increase in the viscosity of the calcium carbonate suspension by several orders of magnitude upon addition of the secondary oil phase compared with the same suspension without secondary liquid phase or without oleic acid. The stability and the rheological properties of the obtained capillary structured materials were studied in relation to the physical properties of the system such as the particle size, interfacial tension between the primary and secondary liquid phases, as well as the particle contact angle at this liquid-liquid interface. We also determined the minimal concentrations of the secondary liquid phase at fixed particle concentration as well as the minimal particle concentration at fixed secondary phase concentration needed to form a capillary suspension. Capillary suspensions formed by this method can find application in structuring pharmaceutical and food formulations as well as a variety of home and personal care products.

Thermally Responsive Capillary Suspensions.

We demonstrate that stimulus-responsive capillary-structured materials can be formed from hydrophobized calcium carbonate particles suspended in a non-polar phase (silicone oil) and bridged by very small amounts of a hydrogel as the secondary aqueous phase. Inclusion of thermally responsive polymers into the aqueous phase yielded a capillary-structured suspension whose rheology is controlled by a change in temperature and can increase its complex modulus by several orders of magnitude because of the gelation of the capillary bridges between the solid particles. We demonstrate that the rheology of the capillary suspension and its response upon temperature changes can be controlled by the gelling properties as little as 0.1 w/w % of the secondary aqueous phase containing 2 wt % of the gelling carbohydrate. Doping the secondary (aqueous) phase with methyl cellulose, which gels at elevated temperatures, gave capillary-structured materials whose viscosity and structural strength can increase by several orders of magnitude as the temperature is increased past the gelling temperature of the methyl cellulose solution. Increasing the methyl cellulose concentration from 0 to 2 w/w % in the secondary (aqueous) phase increases the complex modulus and the yield stress of the capillary suspension of 10 w/w % hydrophobized calcium carbonate in silicone oil by 2 orders of magnitude at a fixed temperature. By using an aqueous solution of a low melting point agarose as a secondary liquid phase, which melts as the temperature is raised, we produced capillary-structured materials whose viscosity and structural strength can decrease by several orders of magnitude as the temperature is increased past the melting temperature of the agarose solution. The development of thermally responsive capillary suspensions can find potential applications in structuring of smart home and personal care products as well as in temperature-triggered change in rheology and release of flavors in foods and actives in pharmaceutical formulations.

Microstructure evolution of phase separated Fe-Cu-Cr-C composite coatings by laser induction hybrid cladding

To investigate the cooling rate on the microstructure evolution of phase separated Fe-Cu composite coatings by laser induction hybrid cladding (LIHC), the different laser scanning speed is adopted to estimate the temperature profiles and cooling rate of the molten pool. When the low laser scanning speed is adopted during LIHC, the Cu-rich spherical particles are embedded dispersedly in the Fe-rich interdendrites at the bottom of coating, while the nanostructured Fe-rich dendrites and the Fe-rich particles are distributed simultaneously in the Cu-rich matrix at the top of coatings. However, the increasing of laser scanning speed can decrease the temperature of the molten pool and increase the cooling rate of the molten pool. This in turn leads to an increase in dynamic supercooling and solute trapping of Cu in the enhanced Fe-rich dendritic refinement, but a decrease in size of Fe- and Cu-rich particles as well as a reduction in size of nanostructured Cu-rich grains inside the Fe-rich particles due to the secondary liquid phase separation.

Particle agglomeration studies in a slurry bubble column due to liquid bridging: Effects of particle size and sparger design

Particle agglomeration can occur in heavy oil upgrading hydroprocessors due to the formation of carbonaceous mesophase, a secondary liquid phase which results from an increased rate of thermal cracking relative to the hydrogenation rate. A cold-flow slurry bubble column operated at atmospheric pressure with an internal diameter of 0.152m was used to examine particle agglomeration behavior and the overall fluid dynamics in a gas-liquid-liquid-solid system. The experimental system consisted of biodiesel (organic continuous phase), aqueous glycerol solutions (immiscible secondary phase), glass beads and nitrogen. The impacts of the secondary liquid loading, secondary liquid viscosity, and particle diameter on the fluid dynamics were established. Particle agglomeration was studied by measuring the axial solid holdup profiles while varying the superficial gas velocity and secondary liquid loading. Enhanced particle agglomeration was observed when increasing the secondary liquid loading, based on the increased solid holdups at the bottom of the column. Three sparger designs (six-legged spider sparger, perforated plate and conical perforate plate) were compared. Following the glycerol addition, the spider sparger was less effective based on the particle sedimentation at lower liquid/solid ratios when compared to the other sparger designs. A Revolution Powder Analyzer (RPA) was also used for complementary measurements to examine whether operational difficulties due to particle agglomeration can be anticipated using a simplified system.

Homogeneous granular microstructures developed by phase separation and rapid solidification of liquid Fe-Sn immiscible alloy

Liquid Fe41.5Sn58.5 alloy was containerlessly solidified under the free-fall microgravity condition inside drop tube. Conspicuous liquid phase separation took place in the broad miscibility gap of 325 K and formed the dispersed pattern microstructures of Fe-rich phase distributed in the matrix of Sn-rich phase. Although the equilibrium phase constitution includes only FeSn and FeSn2 compounds in the phase diagram, the high cooling rate and large undercooling lead to the formation of four new metastable phases αFe, Fe3Sn, (Sn)1 and (Sn)2 respectively. The granular patterns of Fe3Sn phase dominates the droplet solidification process. Phase field simulation reveals that the granular microstructure experiences three evolution stages during liquid phase separation: the nucleation, aggregation, or coalescence and Ostwald ripening of secondary liquid phase, which agrees well with the experimental results. Meanwhile, two kinds of Marangoni migrations play an important role to develop the homogeneous granular structures. EDS analysis shows that the solute contents of various phases increase with the decrease of alloy droplet diameter, while the primary αFe phase is found to contain as much as 18.07 at.% Sn at droplet diameter 73 μm owing to the significant solute trapping during rapid solidification.

The Influences of Carbon and Molybdenum on the Progress of Liquid Phase Sintering and the Microstructure of Boron-Containing Powder Metallurgy Steel

Boron is an optimal alloying element for liquid phase sintering (LPS) of powder metallurgy (PM) Fe-based materials. However, the influences of various alloying elements on the progress of LPS are still undetermined. The aim of this study was to clarify the effects of carbon and molybdenum on the LPS and microstructure of boron-containing PM steel. The results showed that adding 0.5 wt pct C and 1.5 wt pct Mo, and particularly the former, promotes the LPS and increases the sintered density. With the addition of 0.5 wt pct C, liquid can be generated in two distinct regions, and the secondary liquid improves the densification. After 1523 K (1250 °C) sintering, the increases in sintered densities of Fe-0.4B, Fe-0.4B-1.5Mo, Fe-0.4B-0.5C, and Fe-0.4B-1.5Mo-0.5C steels were 0.33, 0.47, 0.56, and 0.64 g/cm3, respectively. Thermodynamic simulation also demonstrated that the increases in sintered densities were correlated with the liquid volumes formed at 1523 K (1250 °C). In conclusion, adding 0.5 wt pct C to B-containing PM steels facilitates the formation of a secondary liquid phase and higher liquid volume, resulting in better densification.

Micro Structural Investigations and Mechanical Properties of Macro Porous Ceramic Materials from Capillary Suspensions

Recently, we have introduced a novel, material‐independent processing method for producing macro porous ceramics with capillary suspensions as a stable precursor. A capillary suspension is a three‐phase system where a small amount of an immiscible secondary liquid is added to a suspension resulting in the formation of a sample spanning particle network. This technology provides open porosities well above 50% and pore sizes ranging from 0.5–100 μm. Here we focus on microstructure formation in the capillary suspensions and its impact on mechanical strength of the corresponding sintered parts. Based on the rheological data and SEM‐images, three regimes (I, II, III) are identified with distinctly different flow properties of the wet suspension and characteristic structural features of the sintered ceramic parts depending on the amount of added secondary liquid phase. The average pore size increases and the pore size distribution changes from monomodal (I) to bimodal (II) and broad multimodal (III) with increasing amount of secondary liquid phase. A clear correlation between the yield stress of the wet suspension and the porosity and pore size is observed for regime (I) and (II). Compressive and flexural strength as well as the Young's modulus monotonically decrease with increasing amount of the secondary liquid phase. Absolute values are mainly determined by the porosity and are well predicted by the Gibson & Ashby model for samples corresponding to regime (I) and (II). The broad pore size distribution in regime (III) results in a significantly lower mechanical strength.

On the phase and interface behavior along the three-phase line of ternary Lennard-Jones mixtures: a collaborative approach based on square gradient theory and molecular dynamics simulations.

This work focuses on the application of a two-way approach, where Molecular Dynamics (MD) simulations and the Square Gradient Theory (SGT) have been used for describing the phase and interface behavior of binary and ternary Lennard-Jones (LJ) mixtures, along a condition of three-phase equilibrium. The unequivocal correspondence between MD and SGT has been achieved by using the global phase diagram of binary mixtures composed by equally sized Lennard-Jones molecules, from which representative molecular parameters for Type-I, Type-II, and Type-III systems have been determined. The so selected binaries have been used then to scale the behavior of a ternary mixture characterized by complex phase equilibrium patterns. For the case of the theoretical SGT approach applied to the Lennard-Jones equation of state was used for predicting phase equilibrium and interfacial properties. In addition the corresponding MD simulations of these macroscopic properties have been conducted for the LJ potential by using equivalent molecular parameters and conditions than in the theoretical approach. Excellent agreement has been observed between the predictions obtained from theory and simulations. Particularly, our results concerning the characterization of the three phase line of a binary Type-III mixture indicate that the bulk liquid (α) and the bulk gas (G) regions are sharply separated by a bulk liquid region (β) for all the explored temperature, pressure, and concentration conditions. The structural analysis of these bulk phases reveals that a secondary liquid phase (β) perfectly wets the liquid-gas interface (α-G), as previously found for Type-II mixture [A. Mejía and L. F. Vega, J. Chem. Phys. 124, 244505 (2006)]. The exploration along the three-phase line for the ternary mixture shows good agreement between SGT and MD. Particularly, we observed the specific influence of a third component in the phase and interface behavior. From all the previous results, we conclude that the SGT applied to an EoS with appropriate mixing rules produces reliable predictions of the properties of ternary mixtures.

Particle agglomeration in gas-liquid-solid fluidized beds with a dispersed immiscible liquid: Study on particle size, shape and material

The formation of a denser and more viscous secondary liquid phase may impact the fluid dynamic behaviour of industrial ebullated bed reactors such as hydroprocessors. This study investigates the effects of particle size, shape and material on the global fluid dynamic behaviour of gas-liquid-liquid-solid fluidized beds subject to particle agglomeration. Ebullated bed experiments were carried out in a 152.4mm diameter column at atmospheric conditions with biodiesel as the continuous liquid, 5wt.% of glycerol as the denser and more viscous dispersed liquid, and nitrogen. Glass spheres with diameters of 4 and 1.5mm were compared to aluminum cylinders with equivalent volume to surface area ratios, where the sphericity of both larger and smaller cylinders was approximately 0.8. In a liquid-solid fluidized bed, the previous particles were in the intermediate settling flow regime (0.2<ReLT∞<500) in biodiesel; nonetheless, coalescing and dispersed bubble flow regimes were obtained with the smaller and larger particles, respectively, at the introduction of gas. Liquid-liquid-solid fluidized bed results established that particle size, shape and material had considerable impacts on agglomeration behaviour. In the gas-liquid-liquid-solid ebullated bed, the 1.5mm glass beads transitioned from coalesced to dispersed bubble flow due to increased particle inertia from agglomeration. Larger glass beads experienced a reduced bed expansion due to agglomeration since the bubble flow regime remained constant. The studied aluminum cylinders did not agglomerate to the same extent as the glass beads due to differing material wetting properties, where negligible clustering occurred with the larger cylinders and an axial agglomerate size distribution was observed with the smaller cylinders. Preliminary experiments in a slurry bubble column using 100 to 150μm glass beads were inoperable at a relatively low glycerol concentration of 0.7wt.% due to considerable sedimentation on the distributor. Interparticle forces relevant to gas-liquid-liquid-solid fluidized beds are discussed, with an emphasis on the relation between fluid and particle properties with respect to attractive forces due to liquid bridging.