Water Phase Research Articles

Humidity dependence of AE activity in sheared quartz gouges and its implication for the micromechanics of friction

Abstract The micromechanics of friction has been investigated from the viewpoint of the healing of real contacts. In this study, the underlying processes of friction are discussed from the viewpoint of the contact junction deformation and failure by measuring the acoustic emission (AE) activity associated with the frictional sliding. Sliding-rate step tests of synthetic quartz gouges sandwiched between metal forcing blocks are conducted using a low-speed (< 700 μm/s) rotary shear apparatus. Humidity is controlled to be dry (~ 5%RH), room (~ 40%RH), humid (100%RH), or wet (saturated without pore pressure control). The frictional behavior is modeled by the rate- and state-dependent friction (RSF) law with two state variables. Shorter critical slip distances of the state evolution would be about the contact junction size, while longer critical slip distances are close to the average diameter of gouge particles. The AE activities are evaluated by AE rate that is the number of AE events per unit sliding distance and the m-value that characterizes the amplitude distribution. As variations in AE activities and the evolution term ( $${b}_{1}$$ b 1 ) with the shorter critical slip distance highly correlate, AE activity may reflect the state of contact junction. While $${b}_{1}$$ b 1 increases with increasing water vapor from dry to humid, AE rate and the m-value are decreased. This may be caused by an increase in inelasticity of the contact junction deformation. Under wet conditions, $${b}_{1}$$ b 1 is similar to that under the humid condition, AE rate is further decreased but the m-value becomes significantly large. This is probably because the failure process of the contact junction changes to less brittle one, implying the impact of phase of water (vapor or liquid) on the brittleness of the failure processes of contact junction. Graphical Abstract

Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs

The understanding of the mechanisms that govern water spontaneous imbibition in mixed wetting capillary channels plays a significant role in operating the oil extraction and energy replenishment for the tight oil reservoirs. In this work, the conservative form phase-field model together with the Navier–Stokes equation is employed to investigate the influence of the mixed wetting distribution and the wetting degree on the imbibition oil recovery effects and microscopic flow characteristics. Results indicate that there exist different oil detachment modes of spontaneous imbibition, and these modes are determined by the coupled effect of mixed wetting fraction and contact angle size. For the mixed wetting capillary with strong oil wetting, when fw is low, spontaneous imbibition can only partially detach the oil. Low fw slows down the fluid flow velocity and leads to the small imbibition oil recovery rate. After that, the influence of the surface contact angle size of the mixed wetting capillary is discussed. For the complete detachment mode, the capillary tube presents a form of water phase saturated filling, achieving the optimal imbibition oil recovery effect. For the mixed wetting capillary tube with the combination of weak water wetting and strong oil wetting (i.e., θw = 75° and θo = 165°), local spontaneous imbibition turbulence can only detach very little oil at the inlet of the water wetting area, ultimately achieving a recovery efficiency of less than 10%. This work illuminates the spontaneous imbibition oil recovery mechanisms and flow potentiality for the different mixed wetting capillary channels.

Spontaneous Bubble Growth Inside High-Saturation-Vapor-Pressure and High-Air-Solubility Liquids and Emulsion Droplets.

Spontaneous bubble growths in liquids are usually triggered by rapid changes in pressure or temperature that can lead to liquid gas supersaturation. Here, we report alternative scenarios of the spontaneous growths of bubbles inside a high-saturation-vapor-pressure and high-air-solubility perfluorocarbon liquid (PP1) that were observed under ambient quiescent conditions. First, we investigate spontaneous bubble growth inside the single PP1 phase, which was left to evaporate freely. The bubble growth is explained by the difference in the PP1 vapor pressure inside the bubble and that above the freely evaporating PP1 interface. Next, we study the bubble growth inside the liquid PP1 covered with a layer of a second air-saturated immiscible liquid: low-air-solubility water or higher-air-solubility ethanol. In both cases, the bubble growth rates were accelerated, indicating mass transfer of air from the water or ethanol phases to the PP1 phase. The bubble growth rates significantly increase for bubbles trapped at the PP1-water or PP1-ethanol interfaces due to faster air diffusion through the thin PP1 liquid films separating the bubbles from the upper phases. Finally, we consider the case of bubbles inside millimeter-sized PP1 emulsion droplets in water or ethanol. The bubble growth inside the droplet leads to an increase in the PP1 droplet's effective buoyancy and to the detachment of the droplets from the substrate. The observed bubble growth rate in the case of emulsion droplets was much faster for PP1 droplets in ethanol than for PP1 droplets in water (minutes vs hours). The underlying physical mechanism of the increase of bubble volumes is the spontaneous mass transfer of both air and PP1 vapor to the bubbles produced by a colloidal diffusion pump effect.

Analysis of the NMR Parameters Shielding and Spin-Spin Coupling Constants of Glycine Conformers.

In this study, we worked at the CCSD/aug-cc-pVTZ level to obtain the conformers of glycine in its neutral and zwitterionic forms in the gas and water phases. We then computed the NMR properties (spin-spin coupling constants and nuclear magnetic shieldings) at the SOPPA/aug-cc-pVTZ-J level. We attempt to elucidate the apparent discrepancy arising from two previous works by Valverde et al. [J. Chem. Phys., 2018, 148, 024305] and Caputo and Provasi [Sci, 2021, 3, 41]. Our optimized structures align with previous theoretical predictions, although some geometries were not found. Additionally, our results suggest that in the gas phase the Δ 1J(O,C) = 1J(Ocis,CO) - 1J(Otrans,CO) is positive when the acid group is in the trans conformation and negative in the cis conformation; however, this trend is not well reproduced in water. From magnetic shielding calculations, we cannot distinguish between an O-H in the cis or trans conformation.

Insight Into the Film‐Forming Properties of Pea Protein Isolate Improved by Cellulose Nanocrystals From the Perspective of Water Phase Stabilization

ABSTRACTThis study is dedicated to explore the effect of cellulose nanocrystal (CNC) on the film formability of pea protein isolate (PPI) and propose the regulation mechanism from the perspective of water phase stabilization. Compared with PPI film, the CNC‐PPI composite films showed the improvement in mechanical properties and barrier properties of water/air. CNC reduced the proportion of free water in the PPI film and induced its conversion to immobilized water. From the microscopic observation of the films, it could be found that 0.25%–0.75% CNC made the dispersion of PPI more uniform, and formed more compact film structure. Meanwhile, the exposure of tyrosine and tryptophan in PPI molecules and the increase in the content of β‐sheet resulted in the improvement of film‐forming properties of PPI. The enhanced stability of water phase induced by CNC restrained the formation of water channels, thus improving the structural integrity of gel network and the film‐forming properties of PPI. This work provided a theoretical reference for regulation of the film‐forming properties of PPI with CNC, which was expected to improve the product performance of PPI films and enrich the application scenarios of PPI.

Ambient-pressure selective hydrogenation of unsaturated aldehydes and ketones into unsaturated alcohols in the water phase.

A universal and green catalytic system for the hydrogenation of unsaturated aldehydes and ketones into the corresponding alcohols with the CC bonds retained under atmospheric hydrogen pressure in the water phase was realized by N-functionalized amino ligand-stabilized ruthenium complexes (o-PPh2C6H4NHMe)[(CH2NHR)2]RuCl2 (R = H, Me, Et) and (o-PPh2C6H4NMe2)[(CH2NHEt)2]RuCl2 with wide substrate compatibility and excellent functionality tolerance. The structural synergism between o-PPh2C6H4NHMe and (CH2NHEt)2 achieves the enhanced performance, with a positive correlation with the electron density of the amino ligand.

Electrostatic spraying encapsulation of probiotic-loaded W/O/W emulsion in sodium alginate microspheres to enhance probiotic survival stability

Water-oil-water (W/O/W) double emulsions have been widely studied and applied in probiotic encapsulation. However, challenges remain in enhancing emulsion stability, protecting encapsulated probiotics from adverse environmental conditions, and improving their viability. This study aimed to optimize the functional components of each phase of the W/O/W emulsion to address these issues. First, the prebiotic fructooligosaccharide, which promotes bacterial growth, was incorporated into the inner water phase. The oil phase (O) was composed of sunflower oil, polyglyceryl polyricinoleate, and different proportions of cocoa butter to investigate the critical role of cocoa butter in maintaining emulsion stability. The effect of varying ratios of whey protein isolate and gum arabic complexes in the outermost water phase on emulsion stability was also systematically investigated. Finally, combined with electrostatic spraying technology, sodium alginate was used as the encapsulating wall material for the probiotic-encapsulated emulsion, and the stability of the system during in vitro gastrointestinal digestion was evaluated. This study utilized electrostatic spray technology to create a protective “armor” around the emulsion encapsulating probiotics. The combination of emulsion encapsulation and electrostatic spray encapsulation significantly improved the survival stability of probiotics, providing a method for maintaining high viability in complex food media.

Pristine and Alkaline Earth Metal‐Decorated C24N24 Fullerenes as Potential Sensors for Halomethanes: A Comparative DFT Investigation

AbstractIn this paper, attempts were made to investigate the adsorption potential of pristine and alkaline earth metal (AEM)‐decorated C24N24 fullerenes toward the halomethanes (XCH3, where X═F, Cl, and Br). By means of DFT calculations, the XCH3⋯C24N24 and ⋯AEM@C24N24 complexes (AEM═Be and Mg) were adequately examined. Upon energetic features, the FCH3⋯Mg@C24N24 complex exhibited the most negative adsorption and interaction energies with values of −21.01 and −22.61 kcal/mol, respectively. From thermodynamic analysis, spontaneous and exothermic natures of XCH3⋯Mg@C24N24 interactions were affirmed, unveiling favorable role of Mg decoration in enhancing the adsorption process. From SAPT analysis, the electrostatic forces dominated the interactions within the XCH3⋯C24N24 and ⋯Be/Mg@C24N24 complexes. Upon FMOs analysis, notable alterations in the distribution of molecular orbitals of studied fullerenes were noticed, indicating the effect of XCH3 adsorption on the electronic features of the studied fullerenes. Further, the Egap values were decreased after the adsorption process which enhanced electrical conductivity of studied fullerens. From DOS plots, the capacity of the C24N24 and Be/Mg@C24N24 to adsorb the XCH3 molecules was affirmed. Solvation energies demonstrated the favorability of the studied adsorption process in the water phase. The present findings established C24N24 and AEM@C24N24 fullerenes as potential effective candidates for detecting halomethanes.

Enhancing the survival of Lactobacillus plantarum via the rational design of whey protein isolate-high acyl gellan gum gelled water-in-oil emulsions

In the present study, single whey protein isolate (WPI) gel, high acyl gellan gum (HG), and WPI-HG composite gels at various WPI concentrations in the water phase within W/O emulsions were prepared, to explore the effects of different gel structures on the stability of the emulsion system and the survival of encapsulated Lactobacillus plantarum. The results indicated that the WPI-HG composite gel had a superior effect to the single WPI or HG gel in the stabilization of the W/O emulsion, because of the decrease in droplet size and increase in viscoelasticity. When the WPI concentration was greater than 4.0wt.%, the WPI-HG gel in the internal aqueous phase contributed to a tremendous improvement in the survival rate of Lactobacillus plantarum during the 6-month storage period. The strengthened network structure and lower water activity in the composite gel help improve the probiotics the viability against the thermal damage and harsh gastrointestinal conditions.

Development of polarizable and hydration-focused water models for the Martini 3 force field

Coarse-grained simulations have been increasingly employed in many fields of molecular chemistry. These models enable the evaluation of complex molecular structures by simplifying their description compared to all-atoms models. Specifically, the Martini 3 force field has been developed to describe biomolecular structures such as proteins, lipids, and carbohydrates. Their “building block” approach has been successfully used in modeling complex systems ranging from carbohydrate solutions, biological membranes, and even deep eutectic solvents. However, one main issue arises when considering interfacial systems: water is represented as a single particle with no effect of electrostatic interactions. In this work, we developed a polarizable water model for the Martini 3 force field, introducing charged particles to model the electrostatic interactions present in water systems accurately. Gaussian Processes were trained with simulation data for both bulk water and cross-interaction parameterization to consistently explore the parameter space and fine-tune our model to the target properties. The developed model showed good performance in reproducing the density and dielectric constant of bulk water. Regarding cross-interaction with other beads, two different sets of parameters were developed. The first, called the polarizable model, is parameterized to reproduce the hydration free energies of the original Martini 3 organic beads. This allows for a good description of free energies of transfer between water and organic phases, the main target property for the Martini 3 force field. The second, called the polarizable-hydration model, is parameterized to match the experimental hydration free energy of selected molecules. This allows for more accurate evaluation of hydration properties, which can be useful for water solutions. In particular, we show that the partitioning and interfacial behavior of nonionic surfactants is improved by the polarizable-hydration model when compared to the standard Martini 3 water model.

Radionuclide transport and retardation in uplifting granitic rocks: Part 2 – Modelling coupled processes in uplift scenarios

Uplifting fractured granitic rocks occur in substantial areas of countries such as Japan. Some of these areas might be considered when siting a deep geological repository for radioactive wastes. A repository site would be selected in such an area only if it is possible to make a safety case, accounting for the changing conditions during uplift. The safety case must include robust arguments that chemical processes in the rocks around the repository will contribute sufficiently to minimise radiological doses to biosphere receptors. Numerical modelling is an important aspect of making these arguments. To provide confidence in the safety arguments, numerical models need to be sufficiently realistic, but also parameterised conservatively (pessimistically). However, model development is challenging because uplift involves many complex couplings between groundwater flow, chemical reactions between water and rock, and changing rock properties. The couplings would affect radionuclide mobilisation and retardation, by influencing diffusive radionuclide fluxes between groundwater flowing in fractures and effectively immobile porewater in the rock matrix (rock matrix diffusion, RMD) and radionuclide partitioning between water and solid phases, via: (i) mineral precipitation/dissolution; (ii) mineral alteration; and (iii) sorption/desorption. It is difficult to represent all this complexity in numerical models while showing that they are parameterised conservatively. Here we present a modelling approach, illustrated by simulation cases for some exemplar radioelements, to identify realistically conservative process conceptualisations and model parameterisations.

A possible origin of life in nonpolar environments.

Explaining the emergence of life is perhaps the central and most challenging question in modern science. We are proposing a new hypothesis concerning the origins of life. The new hypothesis is based on the assumption that during the emergence of life, evolution had to first involve autocatalytic systems which only subsequently acquired the capacity of genetic heredity. Additionally, the key abiotic and early biotic molecules required in the formation of early life, like cofactors, coenzymes, nucleic bases, prosthetic groups, polycyclic aromatic hydrocarbons (PAHs), some pigments, etc. are poorly soluble in aqueous media. To avoid the latter concentration problem, the new hypothesis assumes that life could have emerged in the nonpolar environments or low water systems, or at the interphase of the nonpolar and polar water phase, from where it was subsequently transferred to the aqueous environment. To support our hypothesis, we assume that hydrocarbons and oil on the Earth have abiotic origins.

Estimating Phase Transition Rates in Shallow Cumulus Clouds from Mass Flux. Part II: Vertically Dependent Formulation

Abstract This work continued the investigation of the relationship between phase transition rates and mass flux in trade wind cumulus clouds. The latter was simulated by an LES model initialized with soundings from the Rain in Cumulus over the Ocean (RICO) field project. In Part I, we demonstrated that a very high correlation exists between integral phase transition rates and upward mass flux. In this study, we focused on the vertically dependent variables and showed that a similar high correlation exists between the condensation rate and the upward mass flux . Based on condensation theory, we showed that under quasi-steady approximation condensation rates can be calculated by a linear function of with the slope coefficient dependent only on temperature and pressure. The model data showed that the error of such approximation is less than a few tenths of a percent. The parameterization of the evaporation process is more complex, mostly because of the slow evaporation of raindrops as they fall through the cloud’s unsaturated areas. Nevertheless, it was possible to define the fraction of the evaporation to condensation rate as a function of vertical coordinate z and cloud thickness H. This function can be quite accurately approximated by the third-order polynomials of z and H. It is suggested that the proposed formulation of evaporation together with the quasi-steady formulation of condensation can serve as a parameterization of water phase transition rates in shallow cumulus clouds. Significance Statement This study investigated condensation/evaporation processes in tropical cumulus clouds. The energy exchanged during these processes is an important driving force behind a wide range of atmospheric phenomena. It was found that the vertical distribution of this energy source can be expressed as a linear function of cloud updrafts. This finding suggests a new approach to calculate cloud energy transformations in numerical weather prediction models.

MODELING OF WATER-OIL FLOW IN SHALE POROUS STRUCTURES: EFFECT OF WETTABILITY AND CAPILLARY NUMBERS

Shale oil reservoirs are characterized by dense, extremely low permeability, and poorly developed natural fractures. Hydraulic fracturing technology is often used in extraction to improve recovery. It is important to clarify the mechanism and influence mechanism of displacement in complex porous media coupled with fractures and matrix to enhance oil recovery. In this study, based on the lattice Boltzmann method (LBM) utilizing the fracture-matrix pore coupling model, the authors carried out a study of displacement in organic and inorganic pore space. They systematically investigated the influence mechanisms of wettability and capillary numbers on the oil recovery rate. It was found that the stronger the wettability of the water phase, the higher the oil recovery rate, the lower the residual oil in the form of adsorbed oil film, the larger the capillary numbers, and the higher the oil recovery rate. Oil in organic pore space is more difficult to discharge compared with that in inorganic pore space, and the recovery rate of oil in organic pore space can be effectively improved by increasing the driving pressure and enhancing the properties of the water phase (fracturing fluid).

Investigating the absorption and biodegradation of spilled oil on water using expanded perlite loaded with oil-eating bacteria

ABSTRACT Oil spills in aquatic environments subject to severe ecological consequences, including toxicity, mutagenicity, potential carcinogenicity and disruption of life cycles. The present research aimed to scrutinize the efficacy of expanded perlite as an oil absorbent and its potential for remediating oil spills by incorporating oil-degrading microorganisms. Three types of adsorbents were examined: a control group without microbes, perlite loaded with bacteria and expanded perlite laden with microbes. The expanded perlite, characterized by its large surface area and low density, provided an optimal environment for microbial growth and proliferation. The results indicated that the presence of microbes significantly enhanced both oil absorption and removal and achieved an increase of 58% and 80.45%, respectively, compared to the pre-expansion state. Furthermore, microbial activity played an important role in mitigating oil contamination by reducing the surface tension between water and oil. This effect was attributed to the production of surface-active substances by the oil-degrading bacteria. The reduced surface tension facilitated the separation of residual oil from the water phase. These findings highlight the potential of expanded perlite modified with oil-degrading bacteria as a promising strategy to improve the remediation of oil spills in aquatic ecosystems. The combination of the high surface area of the expanded perlite and the enhanced oil-degrading capabilities of the microorganisms is promising to mitigate the detrimental effects of oil spills on the environment.

Numerical simulation of oil-water separation in sedimentation tank based on CFD-PBM model

ABSTRACT A significant amount of wastewater has been produced from the oilfield extractive fluid with the development of oilfields in recent decades. Settling is the first process in the treatment of oilfield wastewater. As one of the most crucial devices in oilfield wastewater treatment, the vertical sedimentation tank has been widely utilized in the precipitation process. This work aims to explore the properties of vertical sedimentation tanks for oil-water separation and analyze related variables in the separation. First, we utilize the for-profit software Fluent for computational fluid dynamics, in which the RNG k-ε model, the multiphase flow mixing model, and the PBM model are used to simulate the internal flow field distribution in the vertical sedimentation tank under various boundary conditions. Then, the implication of changing the boundary conditions on the vertical sedimentation tanks is analyzed. It is demonstrated that by replacing the PBM model for the homogeneous particle size, the simulation of oil-water two-phase flow in sedimentation tanks is more correctly measured. The findings demonstrate that raising the operating temperature increases the oil content at the output and dewatering rate of the sedimentation tanks by 73.1%; however, above 44°C, the effect of oil removal gradually tends to deteriorate; the longer hydraulic retention time within the 8-h range, the better the effect of oil-water separation, with the best effect occurring at 8 h; and the more viscous the oil phase, the more resistance of the oil droplets to float, increasing the water phase oil-carrying capacity, resulting in a 36.5% reduction in oil content at the outlet and dewatering rate of the settling tanks. The simulation in this paper can provide theoretical direction and conference for the design of vertical sedimentation tanks, as well as improve the performance of oily wastewater treatment facilities.

Separation of Highly Pure Semiconducting Single-Wall Carbon Nanotubes in Alkane Solvents via Double Liquid-Phase Extraction.

This study delves into the distinctive selective property exhibited by a non-conjugated cholesterol-based polymer, poly(CEM11-b-EHA7), in sorting semiconducting single-walled carbon nanotubes (s-SWCNTs) within isooctane. Comprised of 11 repeating units of cholesteryloxycarbonyl-2-hydroxy methacrylate (CEM) and 7 repeating units of 2-ethylhexyl acrylate (EHA), this non-conjugated polymer demonstrates robust supramolecular interactions across the sp2 surface structure of carbon nanotubes and graphene. When coupled with the Double Liquid-Phase Extraction (DLPE) technology, the polymer effectively segregates s-SWCNTs into the isooctane phase (nonpolar) while excluding metallic SWCNTs (m-SWCNTs) in the water phase (polar). DLPE proves particularly efficient in partitioning larger-diameter s-SWCNTs (0.85-1.0 nm) compared to those dispersed directly in isooctane by poly(CEM11-b-EHA7) using direct liquid-phase exfoliation (LPE) techniques for diameters ranging from 0.75 to 0.95 nm. The DLPE method, bolstered by poly(CEM11-b-EHA7), successfully eliminates impurities from s-SWCNT extraction, including residual metallic catalysts and carbonaceous substances, which constitute up to 20% of raw HiPCO SWCNTs. DLPE emerges as a scalable and straightforward approach for selectively extracting s-SWCNTs in nonpolar, low-boiling-point solvents like alkanes. These dispersions hold promise for fabricating fast-drying s-SWCNT inks, which are ideal for printed and flexible thin-film transistors.

Oscillatory Motion of a Camphor Disk on a Water Phase with an Ionic Liquid Sensitive to Transition Metal Ions.

We investigated oscillatory motion of a camphor disk floating on water containing 5 mM hexylethylenediaminium trifluoroacetate (HHexen-TFA) as an ionic liquid (IL). The frequency of the oscillatory motion increased with increasing concentrations of the transition metal ions Cu2+ and Ni2+ but was insensitive to Na+, Ca2+, and Mg2+, the typical metal ions in the water phase. The surface tension of the water phase containing 5 mM HHexen-TFA also increased with increasing concentrations of Cu2+ and Ni2+ but was insensitive to Na+, Ca2+, and Mg2+. Based on density functional theory, metal-ion species-dependent frequency response is discussed with regard to surface tension as the force of self-propulsion and complex formation between HHexen-TFA and metal ions. These results suggest that complex formation between the transition metal ions (Cu2+, Ni2+) and the ethylenediamine group in the IL increases the surface tension around the camphor disk, resulting in an increase in the frequency of oscillatory motion with increasing concentrations of Cu2+ or Ni2+. The present study suggests that the nature of self-propulsion can be created by complexation, which changes the force of self-propulsion.

CFD simulation of turbulent mass transfer of H2S and O2 in a stirring tank.

This study explores the computational fluid dynamics (CFD) simulation of oxygen (O2) and hydrogen sulfide (H2S) mass transfer in a highly turbulent stirring tank. Using the open-source software OpenFOAM, we extended three-dimensional two-phase flow solvers with a rotating mesh feature to model the mass transfer processes between the water and air phases. The accuracy of these simulations was validated against experimental data, demonstrating a strong agreement in the mass transfer rates of H2S and O2. The investigation highlights the impact of turbulence on mass transfer coefficients, confirming the reliability of the solvers for predicting mass transfer in turbulent conditions. The results suggest that these CFD models can serve as effective tools for understanding and optimizing sewer system designs. Additionally, the study highlights the potential of numerical simulations to reduce the need for extensive and potentially hazardous laboratory experiments.

Analisis Retention Time Terhadap Pemisahan Fasa Pada Three Phase Separator di Unit Lube Oil Complex (LOC) III

This research analyzes the retention time of the three phase separator in separating oil, water, and gas phases at PT Pertamina refinery unit IV Cilacap. With an initial retention time ranging from 31 - 34 minutes, there are phases that are still not separated in the separator. This study aims to provide recommendations for retention time based on unseparated phases and how to apply them to the separator at the refinery. This study involves three types of lube oil analyzed, namely DAO, MMO, and LMO. The results show that there is still a difference between the phases at the inlet and outlet which indicates that the phase separation at the initial retention time is still not optimal so that new retention time recommendations need to be made. In the type of DAO lube oil with a retention time of 33 minutes with the largest difference at the inlet and outlet of 0.040. In the type of MMO lube oil with a retention time of 31.2 minutes with the largest difference of 0.037. In the type of LMO lube oil with a retention time of 34.2 minutes with the largest difference of 0.036. After making retention time recommendations based on the results of the difference between inlet and outlet, the retention time recommendations for DAO are 54.6 minutes, MMO is 51.6 minutes, and LMO is 55.8 minutes. The application of retention time recommendations for the separator can be done by optimizing the flow rate at 432,439 m3/day or adding new separator facilities that can accommodate operational volumes of up to 60.4 m3.