Hydrocarbon Droplets Research Articles

Investigation of thermodynamic state evolution, phase transition and mixing of the hydrocarbon droplet in convective supercritical environments

Liquid alkane droplets transit to supercritical fluids under supercritical conditions. However, the subsequent thermodynamic state evolution, phase transition, and mixing in this case, which directly influences combustion in actual diesel engines, need further investigation. We studied the thermodynamic state evolution, phase transition, and mixing of n-heptane droplets in supercritical laminar nitrogen streams through a set of conservation equations. Non-ideal thermodynamic and transport properties were calculated to incorporate the dramatic variation of physical properties in the supercritical regime. We focus on the effects of Reynolds number, ambient pressure, and droplet size on the thermodynamic state evolution, phase transition and mixing of droplets. Results showed that increasing the Reynolds number can accelerate the evolution of thermodynamic states, which leads to the faster transition of droplets from the liquid phase and supercritical fluids to gas-phase mixtures. With the increased Reynolds number, the phase transition rate is increased and the mixing homogeneity is improved due to the enhanced mass transfer. Caused by the negative correlation between mass transfer and ambient pressure, in higher pressure, droplets after the supercritical transition require more time to transition from supercritical fluids to vapor-phase mixtures. Increasing ambient pressure inhibited the droplet phase transition process and deteriorated the mixing homogeneity, but no significant influence was shown on the droplet dynamic evolution process. Smaller droplets transition faster from liquid phase and supercritical fluids to vapor-phase mixtures. The faster thermodynamic state evolution and faster dynamic evolution process of the smaller droplet leads to its more rapid homogeneous mixing with ambient gasses, but the mode of dynamics is independent of the droplet size.

Nusselt and Sherwood correlations of multi-component hydrocarbon droplet in rotating natural convection

The study focused on examining the effect of rotation and high temperatures on the evaporation of multiple components of hydrocarbon droplets in natural convection. It analyzed the Nusselt and Sherwood correlations associated with this phenomenon. The study demonstrates consistent and reliable agreement in both the qualitative and quantitative aspects. The correlations consider rotational phenomenon and enhance the transfers in the vapor phase of mixtures containing multiple components (Heptane, Octane and Decane). They are developed considering the variability of thermophysical and transport properties, as well as the evaporation phenomenon and the heat and mass transfers of the rotating multicomponent hydrocarbon liquid droplet. For a frequency varying between 5 s−1 and 40 s−1, and an ambient temperature varied from 150 °C to 400 °C, the average Nusselt & Sherwood correlations are determined for Prandtl and Schmidt numbers varying between 0.7 < Pr < 0.97, and 1.58 < Sc < 3.13 respectively. The rise of the droplet rotational velocity indicates an augmentation that favors the prevalence of the convection phenomenon over conduction, and elucidating that vapor diffusion due to rotational motion surpasses the significance of the convection phenomenon. the enhancement of Nusselt and Sherwood correlations through the incorporation of rotational motion contributes to the improvement of the evaporation process for hydrocarbon droplets in combustion engines.

Fused silica as an anti-fouling material for oil sands optical instruments

Optical instruments have application in many chemical industries for use in inline observation, measurement, and process control for product and waste streams. Typically, these instruments are fitted with sapphire windows which offer extreme hardness, optical transparency and inertness but can be susceptible to fouling with hydrocarbons in the streams. This work explored the potential of fused silica as an alternative anti-fouling material for optical instrument windows for use in aqueous streams containing hydrocarbons. The advantage of fused silica is that it offers adequate hardness and transparency while retaining chemically reactive silanol groups on its surface. Closed loop experiments conducted with oil sands mature fine tailings (MFT) containing residual bitumen, a hydrocarbon known to cause severe fouling of optical windows, demonstrated no fouling issue on fused silica. The hydrophilicity of the optical surface increased following exposure to the mildly alkaline MFT. We hypothesized that in alkaline aqueous streams the silanol groups are deprotonated to create a negatively charged surface, thereby introducing a repulsive force between the surface and the negatively charged hydrocarbon droplets and increasing the hydrophilicity of both materials. Contrarily, the relatively inert sapphire is limited in its capacity to form negative surface charges and consistently fouled with bitumen. When silanol groups on the fused silica were removed via fluoro-functionalization, it resulted in complete fouling of the optical surface. Finally, bitumen fouling was observed on both fused silica and sapphire surfaces in neutral aqueous environments compared to none on the fused silica in an alkaline environment.

Extraction and manipulation of hydrocarbon droplets by ultrasound radiation

Acoustic tweezers are a method of using sound radiation forces to trap and manipulate objects. Previously, we demonstrated an acoustic tweezer capable of first creating the objects, droplets of CCl4 from a reservoir, before trapping and manipulating them. We achieved this using a single transducer whose field was modified by a low-profile fraxicon (Fresnel axicon) lens exhibiting specific near-field trapping zones and far-field Bessel beam behavior which enable the trapping process. Here, we extend the method to include another class of fluids, complex hydrocarbons, using conventional SAE30 motor oil in water. Furthermore, with the higher power levels used in this study we demonstrate the discovery of a second trapping region in the field generated by our transducer. The non-contact extraction and manipulation of organic and hydrocarbon fluid samples could have significant biological and environmental applications where a container would contaminate, destroy, or otherwise change the samples under investigation.

Floating Liquid Droplets on the Surface of Cryogenic Liquids: Implications for Titan Rain.

Saturn's moon, Titan, has a hydrocarbon-based hydrologic cycle with methane and ethane rainfall. Because of Titan's low gravity, "floating liquid droplets" (coherent droplets of liquid hydrocarbons that float upon a liquid surface) may form on the surface of Titan's hydrocarbon lakes and seas during rainfall. Floating liquid droplets, however, have not been investigated in the laboratory under conditions appropriate for the surface of Titan (cryogenic, hydrocarbon, liquids). We conducted a set of experiments to simulate methane and ethane rainfall under Titan surface conditions (89-94 K, 1.5 bar nitrogen atmosphere) and find that floating ethane droplets form in a wide range of bulk liquid compositions, yet floating methane droplets only form in a narrow compositional range and impact velocity. We find droplet formation is independent of the liquid density and hypothesize that dissolved atmospheric nitrogen in the bulk liquid may repel liquid ethane droplets at the surface. We propose that liquid droplets will form in Titan's methane-rich lakes and seas during ethane rainfall with a droplet radius of ≤3 mm and an impact velocity of ≤0.7 m/s. The presence of these droplets on Titan's lakes may result in a liquid surface layer that is dominated in rainfall composition.

Spontaneous aqueous foaming with fluorosurfactants from a hydrocarbon liquid at ambient conditions

Aqueous foams are ubiquitous in nature and have important applications in enhanced oil recovery, food industry, pharmaceuticals, and firefighting. Foams are intrinsically metastable and degrade quickly to form water when exposed to hydrocarbons. Contrary to the hydrocarbon-induced foam degradation, we describe spontaneous foam generation from a thin layer of immiscible, volatile, hydrocarbon liquid floating on an aqueous fluorosurfactant solution at quiescent, ambient, conditions in a 17-cm diameter vessel. Foaming occurs at under-saturation and is different from the spontaneous foam generation from boiling liquids or cavitation or effervescence of dissolved gases at over-saturated conditions. By varying parameters, we reveal the underlying processes and conditions and quantify their effects on foam volume. We also quantify the unique ability of fluorosurfactants to spontaneously form foams unlike fluorine-free surfactants. This is because the hydrocarbon evaporation drives foam generation and foam-degradation simultaneously, and the degradation dominates for fluorine-free surfactants. To understand the mechanisms of foaming, experiments with a single hydrocarbon droplet floating on the aqueous solution are performed. They show that the vapor formed by the evaporating drop diffuses directly into ambient air below its boiling point but some of it nucleates bubbles at the surfactant laden drop-aqueous-air interface. As the vapor diffuses and accumulates into bubbles, the bubbles grow, rupture, and re-nucleate at the interface. Increased hydrocarbon volatility increases the bubble growth rates. The bubbles trap the hydrocarbon vapors with potential benefits in applications including firefighting and oil spills. Also, the fluorine-free surfactants could be made to foam spontaneously by varying the process parameters identified here and could be important in designing environmentally friendly alternatives to per- and poly- fluoroalkyl substances (PFAS). TeaserFluorosurfactants can self-foam from volatile hydrocarbon liquids under specific conditions, which could be adapted to form spontaneous foams from fluorine-free alternatives. Data and Materials AvailabilityAll data is available in the manuscript or the supplementary materials.

Investigation of supercritical transition and evaporation process of a hydrocarbon droplet under diesel engine-relevant conditions

Fuel spray supercritical transition in the diesel engine has been concerned widely, especially supercharged ones, however, whether the transition can significantly affect the fuel–air mixing under diesel engine-relevant conditions is an issue that still needs evaluating carefully. Thus, the transition and evaporation of individual n-heptane droplets in a nitrogen environment under various ambient conditions were investigated through a high-pressure evaporation model. The influence of ambient pressures on droplet lifetime (τlife) and evaporation rate constant (K) varies with ambient temperature. When Tr < 0.98, with increasing pressure, τlife first increases and then decreases, and K decreases. When 0.98 < Tr < 1.28, as pressure increases, τlife would increase even if K increases, because the increment of initial heat-up periods exceeds the decrease in quasi-steady evaporation periods. When Tr > 1.28, with increasing pressure, τlife decreases, and K increases. As the droplet heats up, the droplet interface is where the binary mixture would reach the critical mixing state if ambient conditions are high enough. Increasing ambient density decreases the minimum ambient temperature (Tm) required for the transition to occur. Above the Tm, transitions occur earlier with the increasing energy density of ambient gas. Increasing ambient density decreases the minimum ambient temperature required for diffusive fuel-gas mixing modes to dominate the mixing process. For droplets large enough to ignore gas–liquid interfacial thickness, the Tm required for the attainment of critical mixing states is almost independent of droplet diameter.

Mass transfer characterization for hydrocarbon liquid–particle collision based on sensitive tracing of fluorescent probe

AbstractThe heat and mass transfer characteristics during the collision process of hydrocarbon droplets and polyethylene particles in a liquid‐containing gas–solid polyethylene fluidized bed reactor significantly affect the product quality. In this work, the mass transfer process of single‐component hydrocarbon and bi‐component hydrocarbon liquid films on the polyethylene particle surface were quantitatively characterized by a newly developed experimental approach, based on a novel synthesized hydrocarbon liquid soluble fluorescent probe for sensitive tracing of hydrocarbon liquid diffusion. It was found that the boiling point and surface tension of the liquid as well as the surface temperature of the particle are the key factors affecting the mass transfer properties of the liquid film. Marangoni convection was observed and characterized on the particle surface. The critical time for the onset of Marangoni flow is between 4 and 8 s.

Ultrasonic near-field based acoustic tweezers for the extraction and manipulation of hydrocarbon droplets

Radiation pressure from acoustic and electromagnetic fields can generate forces sufficient to trap and manipulate objects. In most cases, the objects are pre-existing, but it is also possible for the forces to essentially create the target objects. Recently, we reported on the ability of high power ultrasound to extract and controllably manipulate droplets from the organic solvent CCl4 using a near-field type of acoustic tweezers [Lirette et al., Phys. Rev. Appl. 12, 061001 (2019)]. The extraction used a fraxicon lens which produced trapping zones in the near-field. With the addition of extraction to trapping and manipulation, the process can be considered a form of contact-free pipetting. In the present work, we demonstrate the capability of this system to co-axially extract two droplets of SAE30ND motor oil (between 70%–80% liquid hydrocarbon) at a water interface against a positive radiation pressure. In the experiments with oil, several differences in the process have been observed relative to the CCl4 study: a second near-field trapping zone is revealed; the surface deformation is small and opposite to the direction of extraction; the extraction and trapping forces are sufficient to overcome both interfacial tension and buoyancy; and the target liquid has distinct physical properties, such as density, viscosity, and acoustic impedance. Non-contact and label-free extraction of oil droplets remotely in an aqueous environment could have significant biological and environmental applications. Finding that the process works with two distinct liquids demonstrates its more general applicability and broadens its potential uses.

A study of ignition and combustion of liquid hydrocarbon droplets in premixed fuel/air mixtures in a rapid compression machine

The combustion of two fuels with disparate reactivity such as natural gas and diesel in internal combustion engines has been demonstrated as a means to increase efficiency, reduce fuel costs and reduce pollutant formation in comparison to traditional diesel or spark-ignited engines. However, dual fuel engines are constrained by the onset of uncontrolled fast combustion (i.e., engine knock) as well as incomplete combustion, which can result in high unburned hydrocarbon emissions. To study the fundamental combustion processes of ignition and flame propagation in dual fuel engines, a new method has been developed to inject single isolated liquid hydrocarbon droplets into premixed methane/air mixtures at elevated temperatures and pressures. An opposed-piston rapid compression machine was used in combination with a newly developed piezoelectric droplet injection system that is capable of injecting single liquid hydrocarbon droplets along the stagnation plane of the combustion chamber. A high-speed Schlieren optical system was used for imaging the combustion process in the chamber. Experiments were conducted by injecting diesel droplet of various diameters (50 µm < do < 400 µm), into methane/air mixtures with varying equivalence ratios (0 < ϕ < 1.2) over a range of compressed temperatures (700 K < Tc < 940 K). Multiple autoignition modes was observed in the vicinity of the liquid droplets, which were followed by transition to propagating premixed flames. A computational model was developed with CONVERGE™, which uses a 141 species dual-fuel chemical kinetic mechanism for the gas phase along with a transient, analytical droplet evaporation model to define the boundary conditions at the droplet surface. The simulations capture each of the different ignition modes in the vicinity of the injected spherical diesel droplet, along with bifurcation of the ignition event into a propagating, premixed methane/air flame and a stationary diesel/air diffusion flame.

Surface crystallization mechanism of n-hexane droplets

Revealing the crystallization mechanism of alkane molecules is of great significance to promote the development of the natural gas liquefaction industry. Although many efforts have been made on the crystallization of chain molecules, the surface crystallization mechanism of short-chain alkanes has not yet been solved. In this paper, molecular dynamics simulations were employed to investigate the surface crystallization process of n-hexane nanodroplets and elucidate the surface crystallization mechanism. The results show that the crystallization process of supercooled heavy hydrocarbon droplets can be divided into two stages. The reduction of torsion energy and Lennard‒Jones energy makes important contributions to the droplet crystallization process. The molecules at the vapor-liquid interface tend to be arranged in an orderly manner, and the molecular principal axes are perpendicular to the interface. The molecules at the vapor-solid interface fluctuate strongly along their molecular axes. In addition, the entropy change value for the overall crystalline layer of n-hexane is approximately 1.4 times higher than that of the surface crystalline layer. It is proven that there is a significant energy gain in the surface crystalline layer, which is an important driving force for n-hexane crystallization.

Effect of temperature on heavy hydrocarbon crystallization in natural gas

Understanding the mechanisms of nucleation and crystallization of heavy hydrocarbons in natural gas is significant for controlling alkane crystals, improving nucleation theory, and developing new processing technologies. However, the mechanism of heavy hydrocarbon crystallization at different temperatures is unknown. In this study, the effects of temperature on heavy hydrocarbon crystallization were investigated thermodynamically and kinetically using molecular dynamics simulations. Furthermore, the temperature dependence of the nucleation pathway was elucidated. The results suggest that a crystalline monolayer will first form on the supercooled heavy hydrocarbon droplet surface, followed by layer-by-layer bulk crystallization. As subcooling increases, the droplets and potential energy indicate four states: frustrated crystallization, rapid crystallization, surface crystallization, and vitrification. A temperature range of 130–110 K is ideal for heavy hydrocarbon droplet nucleation. Furthermore, bulk crystallization is determined by the competition between induced nucleation by the initial surface crystalline layer and homogeneous nucleation based on internal nucleation sites. And this depends on the degree of supercooling and determines the final morphology and molecular orientation distribution of crystals. The pathway of heavy hydrocarbon nucleation shifts from a non-classical two-step to a classical process as supercooling increases.

Oxygen droplet combustion in hydrogen under microgravity conditions

The combustion of single liquid oxygen droplets in gaseous hydrogen is investigated experimentally under microgravity conditions to shed light on spray combustion processes in rocket engines. Using a drop tower apparatus, experiments are performed varying the ambient pressure between 0.1–5.7 MPa, which corresponds to a reduced pressure of oxygen pr between 0.02–1.12. The combustion is investigated using high-speed shadowgraph imaging to track the droplet shape and OH-chemiluminescence to identify the flame zone. At low pressures (pr<0.15), the droplet shape is found to change significantly during combustion likely due to the formation of a water ice layer around the droplet. Small jets of oxygen appear to break out of this ice layer, leading to an observed increase in linear and angular momentum of the droplet. At higher pressures, the visible effect of ice formation near the droplet surface decreases. The combustion process at different pressures in the subcritical and the supercritical regime is compared and discussed. The pressure has a limited influence on the flame standoff ratio, whereas it influences the burning rate constant substantially. Specifically, the experimental data suggest a maximum of the burning rate constant near the critical pressure, which is consistent with several experiments on hydrocarbon droplet combustion.

A molecular dynamic study of evaporation/supercritical-transition inter-relationship and multicomponents interaction for alkane/alcohol droplets

The behavior of droplets going through trans-critical conditions from subcritical to supercritical exhibits different features. The influence of multicomponent droplets on the relationship between supercritical transition and evaporation has not been determined. In the present work, molecular dynamic simulations for both single-component and two-component hydrocarbon droplets comprising alkanes (heptane, dodecane, and hexadecane, which are abbreviated to C7, C12, and C16, respectively, in present paper) and alcohol (n-butanol, which is abbreviated to BuOH), whose diameters are 30 nm, are conducted under various trans-critical conditions. To ensure efficiency and accuracy, the simulations are conducted under nitrogen atmosphere. The supercritical transition rate of droplets is quantified by the temporal declining of the maximum fuel mole fraction, and the evaporation rate is measured by the reduction of their radius. The inter-relationship between the supercritical transition and evaporation is mainly influenced by the ambient pressure, where the supercritical transition of droplets becomes more dominant under conditions with higher pressure. Furthermore, the separate phase-change processes and spatial stratification phenomena are discovered for trans-critical n-butanol/hexadecane droplets. Ultimately, by comparing the supercritical transition regions of the binary droplets and the corresponding unary droplets, the influence of intercomponent interaction on the phase-change process of binary droplets is discussed.

Investigation of Supercritical Transition and Evaporation Process of a Hydrocarbon Droplet Under Diesel Engine-Relevant Conditions

Investigation of Supercritical Transition and Evaporation Process of a Hydrocarbon Droplet Under Diesel Engine-Relevant Conditions

A novel strategy for comprehensive optimization of structural and operational parameters in a supersonic separator using computational fluid dynamics modeling

In this study, the effects of several structural and operational parameters affecting the separation efficiency of supersonic separators were investigated by numerical methods. Different turbulence models were used and their accuracies were evaluated. Based on the error analysis, the V2-f turbulence model was more accurate for describing the high swirling turbulent flow than other investigated turbulence models. Therefore, the V2-f turbulence model and particle tracing model were selected to optimize the structure of the convergence part, the diffuser, the drainage port, and the swirler. The cooling performance of three line-type in the convergent section were calculated. The simulation results demonstrated that the convergent section designed by the Witoszynski curve had higher cooling depth compared to the Bi-cubic and Quintic curves. Furthermore, the expansion angle of 2° resulted in the highest stability of fluid flow and therefore was selected in the design of the diffuser. The effect of incorporating the swirler and its structure on the separation performance of supersonic separator was also studied. Three different swirler types, including axial, wall-mounted, and helical, were investigated. It was observed that installing the swirler significantly improved the separation efficiency of the supersonic separator. In addition, the simulation results demonstrated that the separation efficiency was higher for the axial swirler compared to the wall-mounted and helical swirlers. Therefore, for the improved nozzle, the swirling flow was generated by the axial swirler. The optimized axial swirler was constructed from 12 arced vanes each of which had a swirl angle of 40°. For the optimized structure, the effects of operating parameters such as inlet temperature, pressure recovery ratio, density, and droplet size was also investigated. It was concluded that increasing the droplet size and density significantly improved the separation efficiency of the supersonic separator. For hydrocarbon droplets, the separation efficiency improved from 4.6 to 76.7% upon increasing the droplet size from 0.1 to 2 µm.

Crystallization and nucleation mechanism of heavy hydrocarbons in natural gas

In natural gas liquefaction process, the pre-crystallization of heavy components contributes to the heterogeneous nucleation of methane, which may provide insights for the optimization of traditional processing and liquefaction process. However, the crystallization mechanism of heavy hydrocarbons has not been solved yet and the applicability of existing nucleation models to heavy hydrocarbons remains unclear. To tackle this mystery, molecular dynamics simulations were conducted to examine the crystallization of heavy hydrocarbons thermodynamically and kinetically, and explore the nucleation pathway directly related to the crystallization kinetics. The results indicate that the energy cost of heavy hydrocarbon crystallization is the reduction of Lennard-Jones energy and torsion angle energy, and the crystallization is intrinsically a process of orientational symmetry breaking in heavy hydrocarbon structure. Besides, the orientational symmetry breaking is found to be strongly size-dependent and it is more marked for droplets with less than 1000 molecules. A unified picture was proposed for the crystallization pathway, as manifest in the preordering of surface molecules, surface crystallization and internal layer-by-layer crystallization, respectively. Further, the occurrence of internal crystallization and the orientational symmetry breaking are coupled and competitive. Moreover, a non-classical two-step model for the homogeneous nucleation of heavy hydrocarbon droplets was established.

Droplet evaporation and phase transition modes in supercritical environment by molecular dynamic simulation

The phase change process of a single hydrocarbon droplet in a supercritical environment has different features compared with subcritical evaporation. In this study, droplets surrounded by supercritical nitrogen are investigated by molecular dynamic simulation. Dodecane droplets are considered in order to reproduce the phase change process of actual fuel, and the radius ranges from 10 nm to 25 nm under various subcritical, transcritical, and supercritical conditions. The emphasis is to describe the entire phase change process and distinguish its different stages. Under supercritical conditions, traditional D2-law theory is invalid and the radius of droplets increases dramatically accompanied by huge fluctuation after a special time. Based on analysis toward fluid properties crossing this time point, the phases classification for supercritical mixture is provided and three phase change stages are distinguished in order, which can be divided by the onset time of supercritical transition, the disappearance of surface tension, and one-phase diffusion, respectively. Additionally, gas/liquid-like features have been observed in the supercritical binary dodecane–nitrogen coexisting system and the defined pseudo-boiling mole fraction (Xpb) is introduced to clarify such deviation in properties of supercritical mixture. At last, by judging whether supercritical transition and undroplet phenomenon will happen, three phase transition modes are summarized for droplets under supercritical conditions.

Efficient removal of acid from sulfuric acid alkylation reaction products by fiber coalescence technique: Lab-scale and industrial experiments

Removing acid from sulfuric acid alkylation reaction products through fiber media is a new and challenging process in the industry. In this paper, a filler braided from stainless-steel fiber and polytetrafluoroethylene fiber is used to separate the acid-hydrocarbon emulsion. The selected filler characteristics (fiber diameter is 50 μm, bed porosity is 58.3%) and operation condition (superficial velocity is 37.5 m/h) based on lab-scale experiments were applied in the industrial tests, and a good acid-hydrocarbon separation performance was obtained. The separation efficiency was 99.82% and the pressure drop was 43.4 kPa at the superficial velocity of 37.5 m/h. In addition, through the study of fiber wettability, the coalescence mechanism was revealed, which is that the special braided structure induces acid droplets and hydrocarbon droplets to move in different directions, and the droplets on the fiber continue to migrate, coalesce and grow up, thereby achieving the rapid separation of acid and hydrocarbon phases. These findings can facilitate further applications of the sulfuric acid alkylation technology and significantly improve environmental benefits.

Coral reefs and watersheds of the Gulf of Mexico in Veracruz: Hydrocarbon pollution data and bioremediation proposal

Coral reefs and watersheds are important ecosystems. Reefs provide many services to coastal communities, including services such as recreation and commercial fisheries. Watersheds support diverse life forms and provide clean domestic water. Hydrocarbon pollution threatens these ecosystems. Sources of hydrocarbon pollution in Veracruz, Mexico include the petroleum industry as well as tourism and maritime activities. The aim of this study was to evaluate hydrocarbon pollution in reefs and watersheds in the Gulf of Mexico along the coast of Veracruz and to propose effective bioreactor conditions for hydrocarbon bioremediation. We found more than 0.7 ppm of octane and more than 1.8 ppm of nonane in April 2018; and longer-chain and aromatic hydrocarbon in July 2018 including phenanthrene, dotriacontane, tetratriacontane, hexatriacontane, octatriacontane, tetracontane and tetratriacontane. Hydrocarbons concentration in water bodies exceeded the limit for discharge of produced waters of the oil industry of 15 ppm in fresh water and 40 ppm in sea water. A microbial consortium composed of Acinetobacter bouvetti, Defluvibacter lusatiensis, Xanthomonas and Shewanella was cultivated in a bioreactor with 20 gL−1 of diesel and gasoline as only carbon source. The results show that 91.39 ± 1.32% of diesel was degraded in a sea water medium and 97.55 ± 0.74% in a mineral medium after 14 days. Furthermore, 95.05 ± 4.75% of gasoline was degraded in a sea water medium and 98.79 ± 1.19% in a mineral medium over the same time period. Biomass production and hydrocarbon degradation were smaller when the culture medium was based on sea water, probably due to the salt concentration. Some microorganisms produce bioemulsifiers. These compounds increase the availability of hydrocarbons and allow the microorganisms to remediate them in the form of emulsified droplets. In all the experiments, consortium showed that emulsifier activity increased and the diameter of hydrocarbon droplets decreased with time.