Experimental Test Setup for Deoiling Hydrocyclones Using Conventional Pressure Drop Ratio Control

Summary Produced water is a major challenge in the oil and gas industry, especially with the aging of oil fields. Proper treatment of produced water is important in reducing the environmental footprint of oil and gas production. On offshore platforms, hydrocyclones are commonly used for produced-water treatment. However, maintaining the efficiency of hydrocyclones subjected to plant disturbances is a difficult task owing to their compact nature. This paper describes a new experimental test rig built at the Department of Mechanical and Industrial Engineering at the Norwegian University of Science and Technology for testing industrial-scale hydrocyclones. The test setup can emulate first-stage separation and create plant disturbances, such as changes in flow rate, oil concentration, and oil droplet distribution at the inlet of the hydrocyclones. Also, the setup is capable of testing different control algorithms, which helps to maintain the efficiency of hydrocyclones in the presence of such disturbances. The test rig is equipped with various instruments that can monitor such parameters as pressure, flow, temperature, and oil concentration. A typical pressure drop ratio (PDR) control scheme for hydrocyclones is tested in the test rig, which can control the disturbances in the inflow rate. The PDR control scheme does not detect disturbances in the inlet oil concentration and changes in droplet distribution, and these scenarios are shown experimentally in this paper.

Degradation of Rhodococcus erythropolis SY095 modified with functional magnetic Fe 3 O 4 nanoparticles

Alkali-surfactant-polymer flooding technology is widely employed to extract crude oil to enhance its production. The bacterial strain Rhodococcus erythropolis SY095 has shown high degradation activity of alkane of crude oil. In the past, many treatment strategies have been implemented to reduce oil concentration in wastewater. Previous studies mainly focused on the extracellular products of Erythrococcus rather than its degradation properties. In the current study, we designed an immobilization method to modify the surface of R. erythropolis SY095 with functional Fe 3 O 4 nanoparticles (NPs) for biodegradation of crude oil and separation of the immobilized bacteria after degradation. We characterize the synthesized NPs through various methods, including scanning electron microscope energy-dispersive spectrometer, Fourier transform infrared spectroscopy, X-ray diffraction (XRD) and a vibrating sample magnetometer. We found that the size of the synthesized NPs was approximately 100 nm. Our results showed that R. erythropolis SY095 was successfully coated with functional magnetic NPs (MNPs) that could be easily separated from the solution via the application of an external magnetic field. The coated cells had a high tolerance for heavy metals. Our findings demonstrated that the immobilization of MNPs to bacterial surfaces is a promising approach for the degradation of crude oil.

Application of Cogon Grass (Imperata cylindrica) as Biosorbent in Diesel-Filter System for Oil Spill Removal

Imperata cylindrica, often known as cogon grass, is a low-cost and useful sorbent for absorbing oil and optimising processes. The effects of temperature, time, packing density and oil concentration on oil absorption efficiency were investigated and optimised utilising one-factor-at-a-time (OFAT) and response surface methodology (RSM) approaches. Temperature and oil concentration are two important variables in the oil absorption process. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis were used to characterise cogon grass. After treatment and oil absorption, the FTIR method indicated new formation and deformation of functional groups, while SEM revealed changes in the surface and texture of cogon grass, including a roughened and jagged surface. Validation of the RSM model yielded 93.54% efficiency with 22.45 mL oil absorbed at 128 °C temperature and 36 (v/v)% oil concentration while keeping packing density and time constant at 30 min and 0.20 g/cm3, respectively. This study may provide an insight into the usefulness of a statistical approach to maximise the oil absorption of cogon grass as an oil sorbent.

Emulsion Microstructure and Dynamics

<p>Emulsions are kinetically stabilised mixtures of two immiscible fluids (e.g. oil and water). They are encountered in many industrial applications including cosmetics, food, road, drug delivery and paint technology. Despite their wide spread use, the formulation of emulsions remains largely empirical. The nature of the relationships between ingredients, composition, emulsification method and energy input, defining the microstructure (e.g. droplet size distribution and surfactant packing at the oil/water interface), the dynamics (e.g. interdroplet exchange) and the lifetime of emulsions, is still poorly understood. In particular, little work has focused on the mutual interactions between emulsifier and oil molecules and how these affect the properties of the interfacial domain and emulsion dynamics. The emulsion system oil/Triton X-100/water was investigated, where Triton X-100 is a commercially available non ionic surfactant and the oil is one of toluene, p-xylene or octane. The microstructure and the dynamics of these oil/Triton X-100/water emulsions were monitored upon varying oil type, oil concentration, emulsion age and ionic strength while maintaining the oil-to-surfactant weight ratio, temperature, energy input and emulsification method constant. For this purpose, laser scanning confocal microscopy, cryo scanning electron microscopy (cryo-SEM), pulsed field gradient NMR (PFG-NMR), macroscopic phase separation and light scattering techniques were used as experimental techniques. The occurrence of an oil exchange between oil droplets that is not coupled to droplet growth and emulsion destabilization is reported for the three oil systems: toluene, p-xylene or octane. The mixture of two separately stained emulsions, using green and red fluorescing dye molecules, leads to all droplets emitting yellow fluorescence under the confocal microscope within ∼10 min of mixing due to the interdroplet exchange of the two water insoluble dyes. Furthermore, the PFG-NMR data for both toluene and p-xylene systems indicate that, for long observation times, Δ, the echo attenuation of the oil signal decays as a single exponential upon increasing the diffusion parameters. In other words the individual motions of the droplets and oil molecules are described by a unique diffusion coefficient belying the system polydispersity and indicative of a dynamic process occurring on a time scale faster than the observation time. One way to explain this outcome is to consider a motional averaging of the oil diffusion arising from either oil permeation upon droplet collision or reversible coalescence of the droplets. These two mechanisms are supported by the extensive droplet contact observed by cryo-SEM. Such an oil transfer occurring in three distinct oil systems, independently of emulsion destabilization, has not been reported previously. Upon decreasing the NMR observation time below a specific value, Δswitch, a switch of the echo attenuation data was detected between a single exponential and a multiexponential decay, the latter indicative of the emulsion droplet size distribution. The time scale of the oil transfer, Δswitch, was probed upon varying oil type, oil concentration, emulsion age and ionic strength. In particular, the time scale of the oil exchange is an increasing function, spanning from ~300 ms to ~3 s, of droplet concentration in toluene emulsions despite the concomitant increase of the droplet collision frequency. Upon increasing the toluene content and decreasing the mean interdroplet spacing, the oil droplets are kinetically stabilized by the enhancement of the surfactant packing at the oil/water interface. In addition to the surfactant packing at the surface of the oil droplets, ionic strength and droplet size, the rate of oil exchange is controlled by the mutual interactions between oil and Triton X-100 molecules. The rate of oil transfer is a decreasing function from toluene to p-xylene to octane. The increase of the mean droplet size in the same order cannot solely account for the observed slowdown of the oil exchange. The macroscopic phase separation data indicate that the Triton X-100 layer is increasingly robust with respect to oil transfer from toluene to p-xylene to octane. This can be compared with the oil exchange process and explained in terms of oil penetration effects into the surfactant layer and energy cost for hole nucleation.</p>

Emulsion Microstructure and Dynamics

<p>Emulsions are kinetically stabilised mixtures of two immiscible fluids (e.g. oil and water). They are encountered in many industrial applications including cosmetics, food, road, drug delivery and paint technology. Despite their wide spread use, the formulation of emulsions remains largely empirical. The nature of the relationships between ingredients, composition, emulsification method and energy input, defining the microstructure (e.g. droplet size distribution and surfactant packing at the oil/water interface), the dynamics (e.g. interdroplet exchange) and the lifetime of emulsions, is still poorly understood. In particular, little work has focused on the mutual interactions between emulsifier and oil molecules and how these affect the properties of the interfacial domain and emulsion dynamics. The emulsion system oil/Triton X-100/water was investigated, where Triton X-100 is a commercially available non ionic surfactant and the oil is one of toluene, p-xylene or octane. The microstructure and the dynamics of these oil/Triton X-100/water emulsions were monitored upon varying oil type, oil concentration, emulsion age and ionic strength while maintaining the oil-to-surfactant weight ratio, temperature, energy input and emulsification method constant. For this purpose, laser scanning confocal microscopy, cryo scanning electron microscopy (cryo-SEM), pulsed field gradient NMR (PFG-NMR), macroscopic phase separation and light scattering techniques were used as experimental techniques. The occurrence of an oil exchange between oil droplets that is not coupled to droplet growth and emulsion destabilization is reported for the three oil systems: toluene, p-xylene or octane. The mixture of two separately stained emulsions, using green and red fluorescing dye molecules, leads to all droplets emitting yellow fluorescence under the confocal microscope within ∼10 min of mixing due to the interdroplet exchange of the two water insoluble dyes. Furthermore, the PFG-NMR data for both toluene and p-xylene systems indicate that, for long observation times, Δ, the echo attenuation of the oil signal decays as a single exponential upon increasing the diffusion parameters. In other words the individual motions of the droplets and oil molecules are described by a unique diffusion coefficient belying the system polydispersity and indicative of a dynamic process occurring on a time scale faster than the observation time. One way to explain this outcome is to consider a motional averaging of the oil diffusion arising from either oil permeation upon droplet collision or reversible coalescence of the droplets. These two mechanisms are supported by the extensive droplet contact observed by cryo-SEM. Such an oil transfer occurring in three distinct oil systems, independently of emulsion destabilization, has not been reported previously. Upon decreasing the NMR observation time below a specific value, Δswitch, a switch of the echo attenuation data was detected between a single exponential and a multiexponential decay, the latter indicative of the emulsion droplet size distribution. The time scale of the oil transfer, Δswitch, was probed upon varying oil type, oil concentration, emulsion age and ionic strength. In particular, the time scale of the oil exchange is an increasing function, spanning from ~300 ms to ~3 s, of droplet concentration in toluene emulsions despite the concomitant increase of the droplet collision frequency. Upon increasing the toluene content and decreasing the mean interdroplet spacing, the oil droplets are kinetically stabilized by the enhancement of the surfactant packing at the oil/water interface. In addition to the surfactant packing at the surface of the oil droplets, ionic strength and droplet size, the rate of oil exchange is controlled by the mutual interactions between oil and Triton X-100 molecules. The rate of oil transfer is a decreasing function from toluene to p-xylene to octane. The increase of the mean droplet size in the same order cannot solely account for the observed slowdown of the oil exchange. The macroscopic phase separation data indicate that the Triton X-100 layer is increasingly robust with respect to oil transfer from toluene to p-xylene to octane. This can be compared with the oil exchange process and explained in terms of oil penetration effects into the surfactant layer and energy cost for hole nucleation.</p>

Optimizing breeding strategy of Melaleuca cajuputi subsp. cajuputi for a multiple-trait selection: considering the economic weight of traits for oil yield productivity

Melaleuca cajuputi breeding in Indonesia is entering the advanced generation cycle and improvements have been achieved for oil concentration and 1.8 cineole-content. In commercial plantations, the total oil yield is an important factor to ensure the sustainability and continuity of oil production. This variable is calculated based on oil concentration, survival rate, and leaf biomass. However, to date, biomass productivity is maintained through silviculture practices rather than genetics. Therefore, genetic improvement for other traits related to leaf biomass is necessary. This study aimed to optimize the breeding strategy of M. cajuputi for a multiple-trait selection using the economic weight of traits related to oil yield. The economic weight was derived by combining selection results in the past generation breeding population and the assessment in genetic gain trials. The study revealed that leaf biomass should be prioritized as selection criteria for oil concentration in the advanced generation breeding based on the current baseline of the achieved gain. The implication of the economic weight to further generation breeding selection for improving oil yield productivity is that the major traits affecting the oil yield should be incorporated simultaneously for selection in the breeding strategy of M. cajuputi. The leaves biomass could be more weighted than other traits in constructing the index for the multiple-trait selection considering the correlation among the three traits observed.

The Separation of Emulsified Water/Oil Mixtures through Adsorption on Plasma-Treated Polyethylene Powder

This work addresses the preparation and characterization of efficient adsorbents for tertiary treatment (oil content below 100 ppm) of oil/water emulsions. Powdered low-density polyethylene (LDPE) was modified by radio-frequency plasma discharge and then used as a medium for the treatment of emulsified diesel oil/water mixtures in the concentration range from 75 ppm to 200 ppm. Plasma treatment significantly increased the wettability of the LDPE powder, which resulted in enhanced sorption capability of the oil component from emulsions in comparison to untreated powder. Emulsions formed from distilled water and commercial diesel oil (DO) with concentrations below 200 ppm were used as a model of oily polluted water. The emulsions were prepared using ultrasonication without surfactant. The droplet size was directly proportional to sonication time and ranged from 135 nm to 185 nm. A sonication time of 20 min was found to be sufficient to prepare stable emulsions with an average droplet size of approximately 150 nm. The sorption tests were realized in a batch system. The effect of contact time and initial oil concentrations were studied under standard atmospheric conditions at a stirring speed of 340 rpm with an adsorbent particle size of 500 microns. The efficiency of the plasma-treated LDPE powder in oil removal was found to be dependent on the initial oil concentration. It decreased from 96.7% to 79.5% as the initial oil concentration increased from 75 ppm to 200 ppm. The amount of adsorbed oil increased with the increasing contact time. The fastest adsorption was observed during the first 30 min of treatment. The adsorption kinetics for emulsified oils onto sorbent followed a pseudo-second-order kinetic model.

Formulation Optimization and Characterization of Spray-Dried Medium Chain Triglycerides-Rich Oil

Medium chain triglycerides (MCT) are important substrates of the energy metabolism and anabolic processes in mammals. In this study, MCT-rich oil was encapsulated in the mixing ratios of maltodextrin and protein by spray drying to produce spray-dried MCT-rich oil (SMCT). Spray-dried conditions were an inlet temperature of 200 °C, an outlet temperature of 90 °C, and a flow rate of 0.70 L/h. Box–Behnken experimental design and response surface methodology were applied for modeling the influence of formulation variables on powder recovery of SMCT. The key variables were concentration of maltodextrin (10-30% W/W), total protein (5–15% w/w), and MCT-rich oil (5–15% w/w). The microparticles were characterized in terms of particle morphology, yield, Carr's index, moisture content, flowability, hygroscopicity, and powder diffraction. The highest yield of SMCT was 41.19% obtained under the optimized conditions (maltodextrin concentration of 15% w/w, total protein concentration of 8% w/w, MCT-rich oil concentration of 15%). Experimentally obtained values were consistent with those predicted by the model, indicating the suitability of the employed model and the success of the model in optimizing the formulation.

Mechanical properties of bulk Sylgard 184 and its extension with silicone oil

Due to its simple curing and very good mechanical properties, Sylgard 184 belongs to the most widely and frequently used silicones in many industrial applications such as microfluidics and microengineering. On top of that its mechanical properties are further controllable through the curing temperature, which may vary from ambient temperature up to 200 °C; the lower the curing temperature the lower the mechanical properties (Johnston et al. in J Micromech Microeng 24:7, 2014. 10.1088/0960-1317/24/3/035017). However, certain specialised application may require even a softer binder than the low curing temperature allows for. In this study we show that this softening can be achieved with the addition of silicone oil into the Sylgard 184 system. To this end a series of Sylgard 184 samples with varying silicone oil concentrations were prepared and tested (tensile test, rotational rheometer) in order to determine how curing temperature and silicone oil content affect mechanical properties. Curing reaction of the polymer system was found to observe 2nd order kinetics in all cases, regardless the oil concentration used. The results suggest that within the tested concentration range the silicone oil addition can be used to soften commercial silicone Sylgard 184.

Combining cellulose nanofibrils and galactoglucomannans for enhanced stabilization of future food emulsions

The use of wood-derived cellulose nanofibrils (CNFs) or galactoglucomannans (GGM) for emulsion stabilization may be a way to obtain new environmentally friendly emulsifiers. Both have previously been shown to act as emulsifiers, offering physical, and in the case of GGM, oxidative stability to the emulsions. Oil-in-water emulsions were prepared using highly charged (1352 ± 5 µmol/g) CNFs prepared by TEMPO-mediated oxidation, or a coarser commercial CNF, less charged (≈ 70 µmol/g) quality (Exilva forte), and the physical emulsion stability was evaluated by use of droplet size distributions, micrographs and visual appearance. The highly charged, finely fibrillated CNFs stabilized the emulsions more effectively than the coarser, lower charged CNFs, probably due to higher electrostatic repulsions between the fibrils, and a higher surface coverage of the oil droplets due to thinner fibrils. At a constant CNF/oil ratio, the lowest CNF and oil concentration of 0.01 wt % CNFs and 5 wt % oil gave the most stable emulsion, with good stability toward coalescence, but not towards creaming. GGM (0.5 or 1.0 wt %) stabilized emulsions (5 wt % oil) showed no creaming behavior, but a clear bimodal distribution with some destabilization over the storage time of 1 month. Combinations of CNFs and GGM for stabilization of emulsions with 5 wt % oil, provided good stability towards creaming and a slower emulsion destabilization than for GGM alone. GGM could also improve the stability towards oxidation by delaying the initiation of lipid oxidation. Use of CNFs and combinations of GGM and CNFs can thus be away to obtain stable emulsions, such as mayonnaise and beverage emulsions.