Demulsification Effect Research Articles

Broadening of appropriate demulsifier dosage range for latex-containing wastewater by sulfate addition

Investigation of demulsification of polybutadiene latex (PBL) wastewater by polyaluminum chloride (PAC) indicated that there was an appropriate dosage range for latex removal. The demulsification mechanism of PAC was adsorption-charge neutralization and its appropriate dosage range was controlled by zeta potential. When the zeta potential of the mixture was between -15 and 15 mV after adding PAC, the demulsification effect was good. Decreasing the latex concentration in chemical oxygen demand (COD) from 8.0 g/L to 0.2 g/L made the appropriate PAC dosage range narrower and caused the maximum latex removal efficiency to decrease from 95% to 37%. Therefore, more accurate PAC dosage control is required. Moreover, adding 50 mg/L sulfate broadened the appropriate PAC dosage range, resulting in an increase in maximum latex removal efficiency from 37% to 91% for wastewater of 0.2 g COD/L. The addition of sulfate will favor more flexible PAC dosage control in demulsification of PBL wastewater.

Demulsification of dilute O/W emulsion by DC electric field

ABSTRACTIn this article, the effect of demulsification of dilute O/W emulsion in DC electric field and its mechanism are investigated. The results show that the demulsification process of dilute O/W emulsion is divided into three stages: water layer formation, re-emulsification with transverse diffusion and uplift-stabilization of O/W emulsion. There is a critical current in the electro-demulsification of dilute O/W emulsion. Some evidences confirm that O/W emulsion system with surfactant produces a surface tension gradient in the height direction during the stratification process. The critical current together with the surface tension gradient causes different demulsification processes and current variation for different emulsions.

Effect of Demulsification for Crude Oil-in-Water Emulsion: Comparing CO2 and Organic Acids

Acidic substances (naphthenic acids) were found in crude oil, which provides favorable conditions for the formation of surfactants. N,N-Dimethylcyclohexylamine (DMCHA) can activate the naphthenic acid in the crude oil to form the surfactant by noncovalent bonding. This process has an unusual meaning for the crude oil pipelines transportation by the method of forming a low-viscosity oil-in-water emulsion. At the same time, CO2 can be used as a demulsifier to separate crude oil and water at the end of pipeline transportation because the surfactant has a CO2 stimulus response characteristic. In our study, it was found that crude oil-in-water emulsion can be formed and has very good stability. CO2 has a high demulsification efficiency in emulsions with lower crude oil content. For high oil content conditions, the emulsion cannot be demulsified completely by CO2. Since sulfuric acid, hydrochloric acid, and the like are liquid and corrosive, this is not conducive to its application as a demulsifier in crude oil...

Experimental Study on the Effect of pH on the Flocculation Demulsification Efficiency

40 mg/L of artificial emulsified oil water was processed with Al2 (SO4)3, FeCl3 and PAC and PAM as flocculants. Determined the feasible dosage and settling time of each flocculant, researched the effect of pH on the demulsification of different flocculants. The results showed that the demulsification effect of four kinds of flocculants is all affected by pH, and the effect of inorganic flocculant was significantly affected by pH. The maximum removal rates of aluminium sulphate and polyaluminium chloride were 62.0% and 80.7% at pH 7. However, the maximum removal rates of Iron trichloride and polyacrylamide were 77.6% and 85.2% at pH 8.

A Comparative Research of Microwave, Conventional-Heating, and Microwave/Chemical Demulsification of Tahe Heavy-Oil-in-Water Emulsion

Summary We consider the emulsion stabilized by organic base and compound surfactants too stable to separate automatically. To obtain an efficient demulsification technique, the influences of microwave-radiation, conventional-heating, and microwave/chemical methods on the demulsification of heavy-oil-in-water (O/W) emulsions were investigated separately. The results showed that as microwave-radiation time increased, the water-separation rate increased initially and then decreased; with increasing microwave-radiation power, the water-separation rate increased sharply first and then increased moderately; and for both microwave and conventional heating, a higher temperature did not imply a better demulsification effect. In addition, the demulsification efficiency was higher and the separated water was clearer by use of the microwave/chemical approach, which needs less demulsifier in a shorter time for O/W emulsion.

Optimization of vanadium (IV) extraction from stone coal leaching solution by emulsion liquid membrane using response surface methodology

In order to further improve the vanadium (IV) extraction from stone coal leaching solution in one step and reduce the reagent consumption by emulsion liquid membrane (ELM), the experiments using response surface methodology (RSM) was investigated. The liquid membrane was composed of paraffin as membrane stabilizer, D2EHPA as mobile carrier, span80 as surfactant and H2SO4 as stripping solution. Emulsification speed and emulsification time in emulsion formation was optimized to obtain a stable emulsion. An orthogonal 24 Box–Behnken design (BBD) having five replicates at the center point was used to estimate the coefficients of the response function. The linear effects, square effects and interactive effects of the parameters were analyzed by ANOVA. In addition, the signification of the parameters was also ranked. In the further study, the effect of electric demulsification and membrane recycle ability were studied under the optimized parameters. All of the results revealed that RSM was successfully used to optimize the extraction of V (IV) via ELM and indicated the potential industrially application for vanadium concentration and purification in one step from stone coal acid leaching solution.

Research on Crude Oil Demulsification Using the Combined Method of Ultrasound and Chemical Demulsifier

In this paper, experiments of crude oil demulsification using ultrasound, chemical demulsifier, and the combined method of ultrasound and chemical demulsifier, respectively, at different temperatures (40°C, 60°C, and 70°C) are carried out. The photos of water droplet distribution in crude oil, taken with microscopic imaging system, before and after demulsification using the above methods at 70°C are given. Research results show that the combined method of ultrasound and chemical demulsifier has the best demulsification effect, followed by chemical demulsifier. Ultrasound without using chemical demulsifier has the least demulsification effect. Furthermore, the impact of ultrasonic power, treatment time, and temperature on crude oil demulsification using the combined method of ultrasound and chemical demulsifier is studied. Results indicate that the final dehydration rate increases with the increase of temperatures and ultrasonic power and almost does not change with the increase of ultrasonic treatment time. These important conclusions will provide the foundation for an extensive application of the combined method of ultrasound and chemical demulsifier.

A novel 3D porous modified material with cage-like structure: fabrication and its demulsification effect for efficient oil/water separation

A modified 3D porous material with cage-like structure for efficient oil/water and emulsion separation.

Treatment of emulsified oil wastewaters by using chitosan grafted magnetic nanoparticles

In this study, a class of chitosan (CS)-grafted magnetic nanoparticles (MNPs) was synthesized for treating emulsified oil wastewaters. Fe3O4 MNPs were synthesized by using a solvothermal method, followed by coating with aminopropyl-functionalized silica (APFS) to form a surface for further grafting of CS molecular chains. The synthesized MNPs were characterized by various technologies and their demulsification performances were evaluated under various conditions. Results showed that synthetic Fe3O4 MNPs showed negligible demulsification effect, however, under both acidic and neutral conditions, APFS-coated MNPs (Fe3O4@APFS MNPs) exhibited good demulsification effect via electrostatic attraction. It was also found that demulsification performance could be further enhanced upon CS grafting, especially under alkaline condition. Results showed that, under both acidic and neutral conditions, CS-grafted MNPs (Fe3O4@APFS-G-CS MNPs) could efficiently flocculate oil droplets mainly via electrostatic attraction, thereby facilitating magnetic separation; while under alkaline condition, MNPs could overcome electrostatic repulsion and be absorbed onto oil droplet surface via hydrophobic interaction, thereby exhibiting certain demulsification effect under magnetic field. Moreover, under both acidic and neutral conditions, synthesized MNPs could be recycled up to 7 cycles without showing significant loss in demulsification efficiency. In conclusion, CS-grafted MNPs can be easily synthesized and recycled, providing a potential promising approach for efficient treatment of emulsified oil wastewater.

INVESTIGATION ON ENHANCED MICROWAVE DEMULSIFICATION USING INORGANIC SALTS

While the formation of water-in-crude oil (W/O) emulsion is identified to cause serious problems in petroleum industry such as decreasing the oil recovery efficiency, increasing pumping cost, and generating pipeline corrosion, much of its treatment has been focused mostly on gravity separation by mechanical/chemical technology. As an integral part in the process of oil production and transportation, crude oil demulsification has become a significant research attention. Microwave has also long been employed to crude oil demulsification based on the fact that microwave heating can dissipate heat in aqueous medium and raise the energy of the molecules rapidly. However, the research on salts-assisted microwave demulsification has been limited to salts mostly identified in produce-water. The aim of this work is to carry out a comprehensive research on the effect of microwave demulsification and the influence of a variety of inorganic salts to the microwave process. Also, a comparative study on microwave demulsification between heavy oil and light oil were conducted. The obtained results revealed water separation of 47% between irradiated and non-irradiated emulsion for heavy crude oil compared to 13% for light crude oil. Also the effect of different inorganic salts and its optimum amount to promote demulsification were identified.

Ceramic membrane fouling during ultrafiltration of oil/water emulsions: roles played by stabilization surfactants of oil droplets.

Oil/water (O/W) emulsion stabilized by surfactants is the part of oily wastewater that is most difficult to handle. Ceramic membrane ultrafiltration presently is an ideal process to treat O/W emulsions. However, little is known about the fouling mechanism of the ceramic membrane during O/W emulsion treatment. This paper investigated how stabilization surfactants of O/W emulsions influence the irreversible fouling of ceramic membranes during ultrafiltration. An unexpected phenomenon observed was that irreversible fouling was much less when the charge of the stabilization surfactant of O/W emulsions is opposite to the membrane. The less ceramic membrane fouling in this case was proposed to be due to a synergetic steric effect and demulsification effect which prevented the penetration of oil droplets into membrane pores and led to less pore blockage. This proposed mechanism was supported by cross section images of fouled and virgin ceramic membranes taken with scanning electron microscopy, regression results of classical fouling models, and analysis of organic components rejected by the membrane. Furthermore, this mechanism was also verified by the existence of a steric effect and demulsification effect. Our finding suggests that ceramic membrane oppositely charged to the stabilization surfactant should be applied in ultrafiltration of O/W emulsions to alleviate irreversible membrane fouling. It could be a useful rule for ceramic membrane ultrafiltration of oily wastewater.

Study on Stability and Treatment of Surfactant/Polymer Flooding Waste Water

Surfactant is mainly responsible for the stability of oil droplets in surfactant/polymer flooding waste water compared with polymer, decreasing oil-water interfacial tension, and zeta potential on the surface of the oil droplets. Flocculation and demulsification were conducted to remove the stable oil droplets. Demulsifier reverse phase demulsifer-E (RPDE) together with flocculant cationic polyacrylamide is effective in accelerating the coalescence of small oil droplets in surfactant/polymer flooding waste water due to synergistic effect of demulsification and flocculation.

Microwave Demulsification Mechanism and Effect on Petrol Oil Sludge

In the experiments of microwave radiation sludge, the method of air floating, settlement and centrifugal separation are employed to research the demulsification effect of sludge comparative. Results show that: A perfect demulsification effect can be obtained when the radiation intensity is 2w/g, sludge PH value is 2, radiation time is 3-4min, slurry ratio is 1:3 and the oil sludge is processed by microwave.

Demulsification of Crude Oil Emulsion via Ultrasonic Chemical Method

Lots of water and surfactants are poured into the oil well to enhance the exploiting efficiency, so the crude-oil emulsions exploited by this technology contain much water, which is very hard to be separated at present. The demulsifying and separating experiments of the crude-oil emulsion were conducted by using the thermal chemical method and the ultrasonic chemical method separately. The crude oil emulsion samples were provided by the Dagang oil field of China and the water content was 35% volume/volume (v/v). The key influencing factors on demulsification effect were explored by changing the ultrasonic output power, the irradiating time, and the demulsifier amount in the experiments. The dehydrating ratios were compared among the self-made emulsions of different water content with the ultrasonic chemical method. The demulsifying velocity and dehydrating ratio for the high water content crude-oil emulsion was better than that of the emulsion with lower water content in the demulsifying experiments with the ultrasonic chemical method. For the crude-oil emulsion used in this experiment, the result was a dehydrating ratio of 97.7% under the condition of 100 W of ultrasonic output power, 10 min of irradiating time, 50 mg/L of demulsifier, and 75°C of water bath temperature.

Study on Demulsification of Crude Oil Emulsions by Microwave Chemical Method

The demulsifying and separating experiments of crude oil emulsion were performed by using the heating method, the thermal chemical method, the microwave radiating method, and the microwave chemical method separately. The water content of this emulsion was 78 v/v%, and the type was water‐in‐oil (w/o). The influence tendencies of the key factors on demulsification effect were explored by changing the heating temperature, the demulsifier amount used and the microwave radiating time in this paper. With the microwave chemical experiments on the self‐made emulsions of different water content, the demulsification rate and separation efficiency were explored. The type of these emulsions were oil‐in‐water (o/w), water‐in‐oil (w/o) and the multiple type, related to the water content scopes which were less than 30 v/v%, more than 70 v/v% and between them, respectively. The separation effect by the microwave chemical method for the high water content crude oil emulsion was better than that of emulsion with lower water content. For the crude oil used in this experiment, the result could be obtained that the separation efficiency was about 95 v/v% under the conditions of 50 ppm of demulsifier, 10 seconds radiation time, and 1 minute settling time for the microwave chemical method.

DEMULSIFYING DISPERSANT FOR AN EXTENDED WINDOW OF USE

ABSTRACT Recent data with a modern demulsifying oil spill dispersant (Corexit 9500) challenge old viscosity limits for the window of opportunity for dispersant use on viscous oils and emulsions. The demulsification capability of the dispersant to reverse and significantly reduce the viscosity of emulsified oil was demonstrated. This demulsification effect is a prelude to dispersion of the oil. In addition, high effectiveness was demonstrated on no. 6 fuel oil fractions with viscosities over 40,000 cP, well beyond previous indicated limits.