Fresh Emulsion Research Articles

Physical stability, flow properties and droplets characteristics of Balangu(Lallemantia royleana) seed gum / whey protein stabilized submicron emulsions

Balangu (Lallemantia royleana) seed contains valuable gum (BSG) which has good thickening property. The influence of L. royleana seed gum (0–0.3%) on characteristics of soybean oil (20–50%) in water emulsions stabilized by whey protein concentrate (WPC) (0.5–5%) was investigated using response surface methodology. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Increasing the gum concentration to a critical level decreased droplet particle size, creaming index and zeta potential while increased the emulsion polydispersity index and viscosity. Although WPC improved the fresh emulsion characteristics while after 28 of storage it had no stabilizing properties. Optimum formulation for a stable emulsion was found to be 0.15% BSG, 5% WPC and 50% oil content. At this point emulsion had lower particle size and creaming index.

Rheology of fresh cement asphalt emulsion pastes

The rheology of fresh CA pastes of different asphalt emulsion to cement mass ratio (AE/C) with different particle volume fraction was studied. A modified Herschel–Bulkley model was proposed to fit the flow curve of CA pastes and calculate the yield stress and special viscosity (minimum apparent viscosity) of CA pastes. According to the fitted viscosities and yield stresses, a viscosity model was employed to establish the relationship between viscosity and particle volume fraction of CA pastes, and a yield stress model was employed to study the relationship between yield stress and particle volume fraction of CA pastes. Based on the two relations, maximum particle packing density of CA pastes was calculated and the relation between yield stress and viscosity was established to study the rheology of grouting CA pastes. Results indicate CA pastes with different AE/C have significant different relation of viscosity with particle volume fraction and relation of yield stress with particle volume fraction. In the condition of the same viscosity, the yield stress of CA pastes decreases quickly with the increasing AE/C from 0 to 0.4, and then increases slightly with AE/C from 0.4 to 1.0. The yield stress of CA pastes is very low and should be improved for grouting. These works can well reveal the rheology of CA pastes.

Demulsification process of asphalt emulsion in fresh cement-asphalt emulsion paste

The demulsification process of asphalt emulsion in fresh cement asphalt emulsion (CA) paste was investigated by measuring the viscosity and the particle size distribution of CA paste. The morphology evolution of asphalt droplets was also observed by optical microscope. Superplasticizer was used to adjust different demulsifying speed of asphalt emulsion in CA paste. Results indicate that the viscosity development of CA paste can reflect the demulsification process of asphalt emulsion in CA paste. The demulsification process of asphalt emulsion in CA paste has two main stages under the continual induction effect of cement hydration. Asphalt droplets in CA paste are firstly coalesced to big droplets, and then recover their adhesive force. In the first stage, the viscosity of CA paste increases little with the changing particle size distribution. However, the viscosity of CA paste increases sharply in the second stage.

Biopolymer-Based Structuring of Liquid Oil into Soft Solids and Oleogels Using Water-Continuous Emulsions as Templates

Physical trapping of a hydrophobic liquid oil in a matrix of water-soluble biopolymers was achieved using a facile two-step process by first formulating a surfactant-free oil-in-water emulsion stabilized by biopolymers (a protein and a polysaccharide) followed by complete removal of the water phase (by either high- or low-temperature drying of the emulsion) resulting in structured solid systems containing a high concentration of liquid oil (above 97 wt %). The microstructure of these systems was revealed by confocal and cryo-scanning electron microscopy, and the effect of biopolymer concentrations on the consistency of emulsions as well as the dried product was evaluated using a combination of small-amplitude oscillatory shear rheometry and large deformation fracture studies. The oleogel prepared by shearing the dried product showed a high gel strength as well as a certain degree of thixotropic recovery even at high temperatures. Moreover, the reversibility of the process was demonstrated by shearing the dried product in the presence of water to obtain reconstituted emulsions with rheological properties comparable to those of the fresh emulsion.

Factors influencing rheological properties of fresh cement asphalt emulsion paste

As a grouting material, the flow ability and uniformity of fresh cement asphalt emulsion mortar (hereinafter abbreviated as CA mortar) are governed by its rheological properties. The rheological properties of fresh cement asphalt paste were investigated, in which influencing factors, such as type of asphalt emulsion, superplasticizer dosage, and water to cement ratio, were discussed. Results indicate that CA paste with plain asphalt emulsion has too low yield stress to resist segregation, while it has good yield stress when employing asphalt emulsion modified by viscosity modifying agent. Superplasticizer can reduce the initial yield stress and plastic viscosity, however, its water-reducing effect is not obvious for the water-reducing effect of emulsifier in asphalt emulsion. The stability of asphalt emulsion affects the growth rate of plastic viscosity of CA paste, and superplasticizer dosage affects the growth rate of yield stress, which both affects the retention ability of good fluidity. Therefore, a well stable asphalt emulsion modified with viscosity modifying agent, and high superplasticizer dosage (1% recommended in here) are preferred to produce CA mortar.

Effect of Incorporation of whey Protein Concentrate on Quality Characteristic of Buffalo Meat Emulsion Sausage

Incorporation of whey protein concentrate (WPC) at a level of 1, 2, 3 and 4% in buffalo meat was investigated for production, quality characteristic of emulsion sausage (ES). Quality of emulsion sausage was evaluated in terms physicochemical characteristics like moisture content, pH, protein content, water holding capacity (WHC), Extract release volume (ERV), microbiological characteristics like total plat count (TPC) and Yeast and mold count, and sensory characteristic including instrumental colour measurement. It was found that moisture content, protein content, ERV and WHC were significantly (P<0.05) increased in emulsion sausage as result of incorporation of 1-4% of WPC. Addition of 1-2% WPC decreased the pH. However 3-4% addition of WPC caused no change in pH and it remained comparable the pH of the control sample. TPC of ES was found in range of 6.23-6.37 log cfu/g. Emulsion sausage incorporated with whey protein concentrate was acceptable to the panelist. The numerical value of ‘L’ for the samples in fresh condition found in the range of 29.50%- 33.25%. Thus sample had 33.25 % of maximum lightness as compared to 66.75% darkness. The sample of fresh emulsion sausages was greyish brown colour in appearance.

Using PXRD and PONKCS to Determine the Kinetics of Crystallisation of Highly Concentrated NH4NO3 Emulsions

A technique that is known as PONKCS (Partial or no known crystal structure) has become useful in the quantitative determination of solid phases in powder samples that have no known crystal structure, or that have poorly determined crystal structures. This technique was shown to be useful with commercial software, such as Topas®, to quantitatively determine the amorphous phase content of powdered samples that contain a number of crystalline phases within the bulk material. In this study, the method of analysis was applied to the crystallization process of highly concentrated emulsions of ammonium nitrate (HCE of AN) composed of a supersaturated salt solution within a continuous hydrocarbon phase that was stabilized with a variety of surfactants and additives. These emulsions are thermodynamically unstable, and would with time crystallize into the crystalline room temperature phase IV of AN. It was found that by applying slightly different mixing times during the preparation steps, emulsions with different droplets sizes would be obtained. Powder X-ray diffraction was shown to be a useful tool in studying the crystallization process of HCE of AN, where the fresh emulsion would have a characteristic amorphous halo that over time, would then show typical diffraction peaks to appear that correspond with the solid phases of crystalline AN. An assumption was made that the emulsion crystallizes close to about 80 % solid content, thereby allowing for a relative quantification to be made over time. The change with time in the degree of crystallization of the emulsions prepared with different droplet sizes could then be modeled with the well-known Johnson–Mehl–Avrami–Kolmogorov kinetic equation. A crystallization time-related constant and an empirical exponent that reflects the type of nucleation that occurred during the process was determined. The results showed that for a set of emulsions that were prepared by varying only the mixing times and their effective droplet sizes, that the emulsion with the smaller droplet had higher crystallization stability.

Developing environmentally friendly rolling lubricants

Swerea MEFOS pilot mill has been used as a rolling lubricant development tool. The objectives were to improve the lubrication during rolling and thereby improve the operation of the rolling mills. This was done taking into account both the technological aspect, rolling mill output, and the ecological aspect, investigating ways to use rolling lubricants that are more ecologic sustainable, i.e. alternatives to oil-based lubricants as well as the recycling/recovering of oil-based lubricants. Oil-in-water emulsions and an aqueous solution, by the producer termed a conditional emulsion, were tested where the lubricant formulation was altered to optimize the performance for hot rolling of aluminium. Cold-rolling tests were also run on steel coils, where the presence of rust protective oil was studied as well as the influence of aged emulsion behaviour compared with fresh emulsion. Finally, Sapa developed a vacuum evaporator system for recovering oil from dumped emulsion generated during aluminium hot rolling, followed by separation, centrifugation, and flocculation. The cleaned concentrates were reconditioned for reuse. The recycled and recovered emulsion was tested and compared with the original fresh emulsion in Swerea MEFOS pilot mill with results as good as the fresh emulsion.

Recovery of process water from spent emulsions generated in copper cable factory

Treatment of waste emulsions generated in the cable factory from copper wire drawing was investigated using the integrated membrane processes: ultrafiltration (UF) and nanofiltration (NF). The application of UF tubular membranes (MWCO 100kDa) resulted in 98% retention of oil and lubricants, whereas the degree of passage of copper ions (the major component of effluents from cable factory) was 99%. The average permeate flux amounted to 45l/m2h for the transmembrane pressure of 3.5bar during the UF pretreatment of waste emulsions. The Silt Density Index (SDI) values of UF permeates were appropriate for the application of spiral wound membranes in the NF process. The complete removal of oil and lubricants was achieved in NF process and the content of TOC was reduced by more than 90%. The rejection of copper ions in the NF process was 90% and 98% for NF270 and NF90 membranes (FILMTEC), respectively. The quality of NF permeates allows a direct reuse of treated water for the preparation of fresh emulsion.

Purification and Biochemical Characterization of Digestive Lipase in Whiteleg Shrimp

Penaeus vannamei lipase was purified from midgut gland of whiteleg shrimp. Pure lipase (E.C. 3.1.1.3) was obtained after Superdex 200 gel filtration and Resource Q anionic exchange. The pure lipase, which is a glycosylated molecule, is a monomer having a molecular mass of about 44.8kDa, as determined by SDS-PAGE analysis. The lipase hydrolyses short and long-chain triacylglycerols and naphthol derivates at comparable rates. A specific activity of 1787U mg(-1) and 475U mg(-1) was measured with triolein and tributyrin as substrates, respectively, at pH 8.0 and 30°C in the absence of colipase. The lipase showed a K (m, app) of 3.22mM and k (cat, app)/K (m, app) of 0.303 × 10(3) mM(-1) s(-1) using triolein as substrate. Natural detergents, such as sodium deoxycholate, act as potent inhibitors of the lipase. This inhibition can be reversed by adding fresh oil emulsion. Result with tetrahydrolipstatin, an irreversible inhibitor, suggests that the lipase is a serine enzyme. Peptide sequences of the lipase were determined and compared with the full-length sequence of lipase which was obtained by the rapid amplification of cDNA ends method. The full cDNA of the pvl was 1,186bp, with a deduced protein of 362 amino acids that includes a consensus sequence (GXSXG) of the lipase superfamily of α/β-hydrolase. The gene exhibits features of conserved catalytic residues and high homology with various mammalian and insect lipase genes. A potential lid sequence is suggested for pvl.

Membrane processes used for separation of effluents from wire productions

AbstractMetal wires are produced from different metals using drawing methods. The metal used influences both the technology applied and the composition of effluents generated during wires production. Ultrafiltration and nanofiltration are used for the separation of waste emulsions from cable factories. Membrane distillation was proposed for the treatment of acidic saline wastewater generated during steel wire manufacturing (etching). The possibility of the previously mentioned processes application for water reuse is presented. The application of poly(vinylidene fluoride) (PVDF) membranes (FP 100) with the molecular weight cut-off (MWCO) of 100 kDa in the ultrafiltration process resulted in the reduction of 99 % of oil and lubricants in the treated emulsions and allowed complete removal of suspended solids and colloidal substances. Such pre-treated emulsion was subsequently purified by nanofiltration (NF-90-2540) and a 98 % rejection of copper ions was achieved, resulting in a decrease of the permeate electrical conductivity from 3200 μS cm−1 to 260 μS cm−1. The obtained permeate was suitable for preparation of fresh oil emulsion utilized for lubrication in the wire drawing process. The spent etching baths (from steel wire production), which mainly contained FeSO4 and about 1 mass % of sulfuric acid, were separated by membrane distillation. The obtained permeates were: clean water with electrical conductivity at a level of 3–5 μS cm−1. Concentrates (190–200 g of Fe per L) from the MD process were cooled to 295 K, which enabled the FeSO4 crystallization. Application of the above-mentioned membrane processes allows producing high quality product water, over 90 % of water was recovered from the treated wastewaters.

Destabilization‐Enhanced Centrifugation of Metalworking Oil‐in‐Water Emulsions: Effect of Demulsifying Agents

AbstractThe effect of a commercial flocculant (Alpacon® WS009) and two coagulant salts (CaCl2 and AlCl3) on the stability of metalworking oil‐in‐water (O/W) emulsions was examined. Two O/W emulsions were tested: a fresh emulsion, prepared in the laboratory from a commercial concentrate, and a waste metalworking emulsion, provided by a local waste management company, with initial oil concentrations of 32900 and 16900 mg/L, respectively. The emulsion stability was studied at different demulsifier concentrations, temperatures and pH through centrifugation tests, zeta potential and multiple light scattering measurements. Emulsion breakdown is explained by electrostatic repulsion of oil droplets and steric interactions. The former was observed for the laboratory emulsion, while the latter was observed for the waste emulsion. Aluminum chloride was the only effective agent for demulsifying both emulsions.

Recycling of oily ultrafiltration permeates to reformulate O/W emulsions

The feasibility of using ultrafiltration permeates to reformulate oil-in-water (O/W) emulsions was evaluated. In order to optimize the ultrafiltration process the effect of the operating conditions (crossflow velocity, transmembrane pressure and temperature) on permeate flux and chemical oxygen demand (COD) using two tubular ceramic membranes of 20 nm and 100 nm of pore size was studied. Moreover, the critical flux was determined for all operating conditions and for both membranes. Pumping energy consumption was calculated and optimum operating conditions for both membranes were chosen taking into account the minimum energy consumption at a transmembrane pressure well-below the critical pressure in order to minimize membrane fouling. The O/W emulsion was reformulated using the ultrafiltration permeate obtained at these optimum conditions and its properties (surface tension, contact angle, zeta potential, droplet size distribution, stability and foamability) were compared with those of the fresh emulsion. It may be concluded that the ultrafiltration permeate can be used to reformulate the O/W emulsion, taking into account its surfactant content.

Performance Appraisals of Gas/Oil Separation Plants

Summary Produced crude oil typically is processed at a wet-crude-handling facility (WCHF) or a gas/oil separation plant (GOSP). Most of the crude is commingled with water and produced in the form of emulsions that are separated at the GOSP using demulsifiers. In general, the emulsions at the inlet of Saudi Aramco GOSPs are tight, and no free water is observed in the feed stream. This paper describes the performance appraisal of several Saudi Aramco GOSPs. It also discusses the evaluation of these facilities and the efforts undertaken to reduce and optimize the costs of oil/water separation. The most important effort was the characterization of emulsions from various fields. It shows the relative tightness of emulsions and the associated causes of tightness. It has become a diagnostic tool in the quest to understand the causes and treatment of emulsions. The inlet emulsions were characterized by conducting field tests at each of the GOSPs using fresh emulsion samples. The factors associated with the tightness of emulsions include the amount of fine solids such as asphaltenes and scales in the crude, water cuts, temperature, brine chemistry, and shear. Another aspect of oil-water separation investigated was the effect of processing equipment and vessel retrofitting. These included the conversion of two-phase (gas/liquid) separators into three-phase (gas/oil/water) separators, installation of coalescer packs, demulsifier injection strategies, and use of online analyzers. An innovative approach to optimizing oil/water separation is described. The paper provides operational data including demulsifier-treatment costs per barrel of oil, invaluable experience, and many "lessons learned" that are applicable to other crude-oil-treating facilities.

Modelling the yield and texture of comminuted pork products using color and temperature. Effect of fat/lean ratio and starch

Practices to control the processing of finely comminuted meat products are proposed. The objective was to test the practical value of both temperature and light reflection measurements made during emulsification as potential indicators of cooking losses and resulting gel texture in pork sausages emulsified within a wide range of temperatures and starch and fat levels. Prior to cooking, pork batters were chopped for different times to ensure final emulsion temperatures ranging from 5 to 50 °C. The effects of the fat/lean ratio (0.25 and 0.67) and starch addition (0.8 and 3.2% w:w) on temperature and optical reflection were also investigated. The chopping increased the temperature and decreased the light reflection of fresh meat emulsion. There was no relevant loss of emulsifying capacity at emulsion temperature below 30 °C and lightness values over 70 CIE units. The losses and textural parameters of cooked emulsions could be predicted by means of non-linear regression equations based on the temperature and color of the raw emulsion. The determination coefficients obtained ranged from 0.89 to 0.99. The prediction models needed to be fitted to each batter formulation, especially in the presence of reduced levels of gelation agents (meat protein and starch). Lightness was a better predictor than chromaticity, since it decreased constantly with chopping in the range of final emulsion temperatures studied (5–50 °C). This confirms previous studies that lightness could be used for monitoring emulsion stability in meat batters.

The oily wastewater treatment using the nanofiltration process

The oily wastewater treatment using the nanofiltration process The objective of this work was to investigate the possibility of oily wastewater treatment using the nanofiltration (NF) process. The NF studies were carried out with a permeate obtained from ultrafiltration (UF) (used for the treatment of the oily wastewater from metal industry). The influence of transmembrane pressure on a permeate flux, the degree of the rejection of oil and inorganic compounds was investigated. The studies on the NF treatment of oily wastewater demonstrated a high effectiveness of the rejection of oil and inorganic compounds. The permeate obtained from the treatment was free of oil. Moreover, the retention coefficient of the inorganic compounds was higher than 75% for all the cations examined (Na+, K+, Mg2+, Ca2+, Zn2+, Cu2+) and higher than 95% for sulphates. Therefore, the permeate obtained in the NF process can be reused for fresh emulsion preparation.

Regeneration of an oil-in-water emulsion after use in an industrial copper rolling process

The stability of two oil-in-water emulsions ( smoothing emulsion and finishing emulsion) used as lubricants and coolants in an industrial copper rolling process was studied as a function of time. Four parameters were measured: droplet size distribution, zeta potential, surface tension and contact angle. Experimental results show that zeta potential ( ξ) is the main indicator of emulsion stability: for ξ values higher than −10 mV the emulsion is completely destabilized and it is not suitable for the rolling process. Furthermore, emulsion regeneration is only possible for zeta potential values around −20 mV. For this reason, a sample from the finishing emulsion with a zeta potential value of −16.7 mV was chosen to check the suitability of seven nonionic surfactants in order to try its regeneration. No relevant variation was observed between the surface tension and droplet size distribution of the regenerated and the original emulsion. Likewise, zeta potential was lowered to values around −40 mV for all tests, close to the zeta potential of the fresh emulsion. Contact angles over a copper surface show different behavior depending on the surfactant. Though all surfactants decrease the initial contact angle (44.4°), the final values obtained after surfactant addition varied from 24.1° (lowest value) to 40.1° (highest one). In spite of its high foaming ability, compared to the other surfactants tested, Cremophor ® EL was found be the most suitable surfactant for emulsion regeneration.

Microbial deterioration of surface paint coatings.

Bacterial and fungal species associated with the normal and deteriorated painted surface in Owerri, Imo State were isolated and identified. The bacteria genera isolated were Pseudomonas, Bacillus, Micrococcus, Staphylococcus, Enterobacter and Streptomces, whereas the fungal genera isolated were Rhizopus, Penicillium, Cladosporium,. Aspergillus, Alternaria, Fusarium, and Curvularia. More bacterial and fungal isolates were obtained from biodeteriorated surfaces than normal painted surfaces. The occurrence of these microbial isolates in normal : deteriorated painted surfaces were found to be Pseudomonas (90:100%), Bacillus (80:100%), Rhizopus (60:100%) and Aspergillus flavus (50:90%) Penicillium, Staphylococcus, Enterobacter, Aspergillus niger, Cladosporium, Alternaria Streptococcus, Fusarium, Curvularia and Micrococcus occurred only between 20 and 70%in the biodeteriorated samples. Bacillus sp., Pseudomonas sp., Rhizopus sp. and Aspergillus niger were isolated from undeteriorated (normal) painted surfaces. Besides the organisms isolated from normal pain, Penicillium sp., Cladosporium, Aspergillus flavus, Alternaria sp., Fusarium sp., Micrococcus sp., Staphylococcus aureus Enterobacter sp., and Streptococcus sp. were isolated in the deteriorated paint. None of the isolates was able to grow on fresh emulsion paint films. This study has established the microbial flora of deteriorated painted surfaces in the tropics. Global Jnl Pure and Applied Sciences Vol.10(4) 2004: 485-490

The rheological characterization and pipeline flow of high concentration water-in-oil emulsions

The rheological and transport properties of highly concentrated inverse phase (water-in-oil, w/o) emulsions were studied. The concentration of the aqueous (disperse) phase was 94%. The flow curve of fresh emulsion is described by the Cross equation. Aging leads to changes in the rheological behavior of the emulsion: the Newtonian flow domain disappears, the apparent viscosity increases and typical yielding is observed. The flow curve of this “aged” emulsion is described by the Hershel–Bulkley equation. Preliminary deformations lead to a slight dilatant effect. Shearing the emulsion through a transition stress threshold of approximately 300 Pa leads to radical changes in the rheological behavior, including loss of stability in tube flow. Stable invert, highly concentrated emulsions have elastic moduli that do not depend on stress and are not affected by transition through the yield limit. Their storage modulus is stable with respect to the deformation amplitude up to 10% strain, while the loss modulus is very sensitive to deformation amplitude. The rheological properties of samples taken from a pipeline are close to the properties of ‘’aged” samples. Experimental data obtained in a rheometer can be used successfully for the prediction of the transport characteristics of the emulsion in pipelines for pipes of large diameter. The choice of the flow curve parameters is not crucial for the results of calculations of transport characteristics of the emulsion.

Treatment of spent emulsion from a cable factory by an integrated UF/NF membrane system

The potential of using the integrated membrane system based on ultrafiltration (UF) and nanofiltration (NF) in purification of effluents from a cable factory was investigated. The UF experiments were performed using tubular membranes taking into consideration the composition of the treated effluents. The UF process was carried out within the range of parameters recommended for oil emulsion. The application of UF membranes with MWCO of 100 kDa results in the complete rejection of suspended solids and the retention of oil and lubricants at a level of 99%. The UF membranes employed exhibit a 96% passage of copper ions, which is the major component of spent emulsion. The average permeate flux during the UF pretreatment of wastewater produce during copper wire drawing amounts 45 l/m 2h for the transmembrane pressure of 2 bar. The resulting UF permeate was further purified by NF to achieve the retention of remaining pollutants (oil and lubricants) and to reduce the content of copper ions. As a result of the NF process, the content of organic compounds in the permeate determined as TOC was below 1 mg/dm 3, and the rejection of copper ions obtained with the AFC30 membrane was at a level of 92%. The quality of permeate obtained by the application of an UF/NF integrated membrane system allows the direct reuse of treated water for fresh emulsion top up.