DESTABILIZATION OF WATER IN BITUMEN EMULSION BY WASHING WITH WATER

In order to get more information about the mechanism of stabilization of water-in-diluted-bitumen emulsion, bitumen diluted with toluene (10%, 25%, and 50% in volume) was “washed” using different amounts of water (0.20% in volume). The washing water was emulsified and then separated by high-speed ultra-centrifugation. The supernatant was then used to create a second w/o emulsion with the addition of new water. Stability of the new emulsion was measured in terms of the water separation rate under a low centrifugal force

It has been found that a very stable w/o emulsion was obtained in original diluted bitumen. However, after the diluted bitumen was pre-washed with a few per cent of water, the second emulsion became unstable. This indicates a significant effect of pre-washing with water on emulsion stability, possibly through the removal of emulsion stabilizing agents. Based on analytical results such as surface tension, and FTIR spectra, it appears that a small fraction of bitumen, mostly polar compounds such as carbonic acids and other oxygen-containing compounds, are responsible for the emulsion stabilization. Emulsion stability decreases with increasing volume of washing water but increases with the bitumen concentration.     

Preparation of an SBS Latex–Modified Bitumen Emulsion and Performance Assessment

Abstract

For resolving the contradiction of the stability between styrene-butadiene-styrene (SBS)-modified bitumen emulsion and the concentration of SBS, a method of preparing SBS latex is provided in this article. Results showed that SBS latex had good stability properties and performance. The effect of emulsifier concentration on the storage stability showed that the maximum stability of SBS latex–modified bitumen emulsion (SBS-LMBE) was obtained at emulsifier weight concentration 1.0% and addition of SBS latex to bitumen emulsion enhanced the difficulty of emulsification. The effects of SBS latex on bitumen properties showed the penetration decreased, whereas the softening point and ductility at 5°C increased, which means that SBS latex plays a role in improving the properties of bitumen. Compared to the base bitumen, saturate and aromatic of evaporation residue of SBS-LMBE decreased. However, resin and asphaltene increased. Analysis of the relationship between the components and properties of bitumen showed that the components change caused by SBS latex was beneficial to the properties of bitumen. The colloidal index (CI) showed that SBS latex also made the colloidal system more stable.     

MINERAL MATTER AND CLAY-ORGANIC COMPLEXES IN OIL SANDS EXTRACTION PROCESSES

ABSTRACT

Differences in oil sands processability and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailings as well as carry over of water and mineral matter with the bitumen product. The nature of the organic component of clay-organic complexes extracted from various streams in an oil sands recovery process is discussed in relation to the stability of both water-in-oil and oil-in-water emulsions formed.

The samples were obtained from Suncor's oil sands extraction plant located in Fort McMurray, Alberta. Samples were obtained from throughout the extraction process from the primary froth through to the final diluted bitumen product. These samples have been studied with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) as well as with other techniques such as interfacial tension measurements. The data indicates that high water content products originate, to a great extent, from the presence of a very hydrophilic organic matrix attached to the surface of the clay and heavy metal minerals.     

VISCOSITY OF WATER IN OIL EMULSIONS

ABSTRACT

Increase in water cut in oil fields generally calls for an increase in the capacity of transport pipelines. Proper design and operation of the latter requires good knowledge of the thermophysical properties of flow resistance of crude-oil water mixtures. An experimental program aimed at measurements of oil-water emulsion viscosity for water cuts prior to the inversion point was conducted.

The present work reports on measurements of Nimr crude oil-water mixtures viscosity for different water cuts and a typical range of temperatures representative of field conditions (20°-50°C). Three mixing intensities of 10⁶, 5×10⁶ and 15×10⁶ erg/cm-sec generated by a dynamic coalescer and directly relevant to field conditions were used.

The results suggest that the inversion point occurs around a value of water cut of 35%. Both Newtonian and non-Newtonian (pseudo-plastic) behaviour were observed, and the ASTM viscosity model is found to be applicable to the emulsions. The effect of the mixing intensity on the resulting emulsion viscosity was found to be important at low temperatures and decreased at high temperatures. The experimental data fitted the available correlations in the literature.     

Effects of the compound system of alkali and alkyl glycosides on the stability of oil-in-water emulsions

Abstract

The effects of Na₂CO₃, nonionic surfactant octyldecyl glucoside (APG0810), and inorganic salt addition on the water separation ratio and apparent viscosity of oil-in-water (O/W) emulsions were investigated. The influences of this compound system on the stability of the emulsion and its synergistic mechanism were also analyzed. Results revealed that in the first compound situation, when APG was selected as the main surfactant and had a concentration of 0.1%, the mass concentration of Na₂CO₃ was 0.4%, the emulsion exhibited the strongest stability, and the water separation ratio at 30?°C for 120?min was 20.3%. In the second compound situation, when Na₂CO₃ was used as the main surfactant and had a concentration of 0.1%, the mass concentration of APG was 0.4%, the emulsion displayed the strongest stability, and the water separation ratio at 30?°C for 120?min was 57.8%. The stability of the O/W emulsion increased with increased NaCl addition, and a higher salt concentration corresponded to a lower water separation ratio. After CaCl₂ addition, the apparent viscosity of the emulsion increased sharply, and the O/W emulsion underwent phase inversion to become an water-in-oil (W/O) emulsion. Within the set mass concentration range, increased salt concentration caused the apparent viscosity of the W/O emulsion measured at 50?°C and 30?rpm to decrease gradually but still exceeded 1500?mPa·s.     

THE DETERMINATION OF WATER IN BIOMASS-DERIVED LIQUID FUELS

ABSTRACT

The Dean and Stark distillation is an appropriate method for the determination of water in coal tar, bitumen and petroleum-like products. This article shows, however, that a direct application of the Dean and Stark method for the determination of water in biomass-derived liquid fuels results in incorrect estimates. Inaccuracies are due to the presence of soluble organics in the aqueous phase, which apparently form azeotropic mixtures with water and xylene and which condense and are trapped as distillate in the graduated cylinder. Instead, a Karl Fischer determination of water is recommended in the case of biomass-derived liquid fuels     

Characterization of Asphaltenes and Resins Separated from Water-in-Oil Emulsions

Abstract

Knowledge of the properties and behavior of asphaltenes and resins is indispensable for the design of preventive and curative measure for emulsion problems created by the presence of asphaltene, resins, and other organic and inorganic solids. In order to understand the phenomena of water-oil emulsions formed in Kuwaiti oil fields and determine the factors involved in the stabilization of these emulsions, the role of asphaltenes, resins and wax separated from various samples of oil field emulsions formed in Burgan oil field have been evaluated. Physicochemical properties of asphaltenes, resins, wax, and de-asphalted de-resined (DADR) oil samples have been studied via FT-IR, ¹H, and ¹³C NMR, elemental analysis, and differential scanning calorimetry (DSC). These emulsion samples contain different amounts of water ranges from 24 to 35%, asphaltene content ranges from 0.9 to 1.7%, and resin content from 3.7 to 4.6%. IR-FT spectra were performed to identify the various functional groups which have an effect on the stability of water-oil emulsions. The freezing behavior of an emulsion was characterized by differential scanning calorimetry to determine whether the water in the emulsion is free water or emulsified water.     

Water-in-Crude Oil Emulsion Stability Investigation

Abstract

The water-in-crude oil emulsion has great importance in the oil industry. The stability of water-in-crude oil emulsion is investigated over a wide range of parameters. These parameters are water concentration (10–50%), surfactant concentration (0.1–1%), mixing speed (500–2, 000 rpm), salt concentration (0–5%), polymer concentration (0–1, 000 ppm), and temperature (13–40^○C). The physical properties of water-in-crude oil emulsion in terms of density, viscosity, and interfacial tension are measured by Pycnometer, Ostwald viscometer, and spinning drop tensiometer, respectively. The stability of water-in-crude oil emulsion is studied for each case in details. This investigation shows that the presence of the emulsifying agent is necessary for stable emulsion, and stability gradually decreases with water concentration. The presence of 5% NaCl or 1, 000 ppm of Alcoflood polymer provides 100% stable emulsion. Emulsion stability reduces with temperature. Impeller type has a strong effect on the emulsion stability. S-curved blade impeller provides 100% stable emulsion for more than 2 days.     

ISOLATION AND CHARACTERIZATION OF NATURAL SURFACTANTS FROM CHINESE OIL SAND BITUMENS

Abstract

Natural surfactants(NS) have been isolated from four Chinese oil sand bitumens (NNY,NSY,SNE,SUG) using the method of solvent extraction. These compounds were analyzed by IR and their interfacial tension (γ) against pH were measured. The results were compared with these obtained for fractions separated from the bitumen by conventional methods. The factors of NS to the extraction of bitumen from oil sand by hot water were investigated.     

Investigation of Kinetic and Rheological Properties for the Demulsification Process

Chemical demulsification process is the most widely applied method of treating water in crude oil emulsions and involves the use of chemical additives to accelerate the emulsion breaking process. Hence, five demulsifiers were prepared in two steps. In the first step, the nonyl phenol was polymerized with formaldehyde to obtain five different molecular weights polymers. In the second step, the resulting polymers were ethoxylated with 50 ethylene oxide units and propoxylated with 10 propylene oxide units, yielding (D₁–D₅). The demulsification efficiency of these demulsifiers was investigated. The influence of viscosity on the droplet diameter for water-in-crude oil emulsion with three different ratios; 30:70, 50:50 and 70:30 (v/v) w/o emulsions were examined. The results showed that, the viscosity of w/o emulsion was strongly augmented by increasing volume of water before reaching the inversion point. The yield point which is required to start the flow decreases with decreasing water percent. The coalescence rate increases with increasing drop size for D₅ as a representative sample. Results show that, the droplet size increases with increasing water content. The efficiency of water separation increases as the molecular weight increase.     

A PHYSICAL CHEMICAL EXPLANATION FOR DETERIORATION IN THE HOT WATER PROCESSABILITY OF ATHABASCA OIL SAND DUE TO AGING

ABSTRACT

The oxidation of sulphide minerals during storage of Athabasca oil sands causes solubilization of inorganic salts which affect recovery of bitumen during hot water extraction. DLVO and Ionizable Surface Group Model theories accurately predict that the level of soluble salts produced is sufficient to cause coagulation of the fine particles during the process which leads to a deterioration in froth quality and loss of bitumen recovery. The rate of aging is specific to each oil sand but storage of oil sands under an inert atmosphere in air-tight container at sub-zero temperatures will minimize oxidation.     

The Kinetics and Inhibition of Chloride Hydrolysis in Canadian Bitumen

Abstract

Chloride salts in heavy oils can cause significant corrosion and fouling of refinery equipment, because desalting is not completely effective. The kinetics of the reaction of chloride salts with steam in diluted bitumen at 250°C was affected by reaction and diffusion in the solid salt particles. Four inhibitors based on alkaline–earth compounds were effective in reducing the initial rate of hydrolysis, thereby offering potential protection to refinery equipment. Chlorides were retained by the inhibitors even at 550°C. The physical association between salt particles and the inhibitors suspended in the crude oil was important for effective trapping of released chloride.     

Stability of Water-in-Crude Oil Emulsions: Effect of Oil Aromaticity,Resins to Asphaltene Ratio,and pH of Water

Abstract

The formation of tight water-in-oil emulsions during production and transport of crude oils is a great problem challenging the petroleum industry. Tremendous research works are directed to understanding the mechanism of formation, stabilization, and controlling of oil field emulsions. This article presents experimental results of some of the factors controlling the formation and stabilization of water-in-crude oil emulsions. In this study, asphaltenes and resins separated from emulsion samples collected from Burgan oil field in Kuwait have been used to study emulsion stability. Model oils of resin to asphaltene ratio of 5:1 and toluene-heptane mixtures have been used to study the effect of oil aromaticity on emulsion stability. Results indicate that at low toluene content (below 20%) or high content (above 40%) less stable emulsions are formed. At a threshold value of 30% toluene, a very tight model oil emulsion is formed. The effect of resins to asphaltene (R/A) ratio on stability of model oil has also been investigated. Results reported in this paper show that as the R/A increases the emulsions become less stable. The effect of pH on stability of model oil emulsion made of 50/50 heptane-toluene mixture having R/A ratio of 5:1 have been studied. Experimental results revealed that as the pH of the aqueous phase of model oil increased from 2 to 10, the emulsion became less stable. At high pH, the asphaltene particles are subjected to complete ionization leading to destruction of the water-oil interface and eventually breakdown of the emulsion.     

Demulsification of Crude Oil Emulsion via Ultrasonic Chemical Method

Abstract

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 OF COMPOSITION OF NIGERIAN TAR SAND BITUMEN

Abstract

Compositional characterization techniques developed for high-boiling heavy ends of petroleum have been applied to Nigerian tar sand bitumen. The bitumen was subjected to ion-exchange and ferric chloride coordination chromatography to separate acids, bases and neutral nitrogen compounds. The remaining Hydrocarbon plus fraction was separated into saturates, monoarmatics, diaromatics and polyaromatic plus polar compounds on dual packed column of silica - alumina gels. Simulated distillation data were also obtained for the bitumen and were used to plot a boiling point distribution curve.

Results of the characterization are compared with results in literature for tar sand bitumens and petroleum. Comparison of the results with the Utah and the Athabasca bitumens provides a basis for the evaluation of the Nigerian bitumen because considerable information about the processing characteristics of the Athabasca bitumen have been reported by many researchers.

Simulated distillation and chromatographic separation data indicate that the bitumen used in this present study closely resembles the Athabasca and the Utah tar sand bitumens with respect to hydrocarbon/non-hydrocarbon distribution, and the high-boiling petroleum fraction with respect to non-distilling portion. Information about the composition of bitumens and heavy oils is needed because of the prospect of using heavy oils including bitumens as energy sources.     

EFFECT OF ASPHALTENE AND RESINS ON THE STABILITY OF WATER-IN-WAXY OIL EMULSIONS

ABSTRACT

Asphaltene, resins and paraffin waxes, their mutual interactions and their influence on the stability of water-in-oil emulsions have been studied. 20 wt % paraffin wax dissolved in decalin was used to model the waxy crude oil. Asphaltene and resins separated from a crude oil were used to stabilize the water-in-oil emulsions. Synthetic formation water was utilized as the aqueous phase of the emulsion. The emulsion stability increased with increasing the concentration of asphaltene with a subsequent decrease in the average particle size distribution of the emulsion. Resins alone are not capable of stabilizing the emulsion, however, in the presence of asphaltene they form very stable emulsions. Dynamic viscosity and pour point measurements provided evidence for resins-paraffin waxes interactions. Asphaltene in the form of solid aggregates form suitable nuclei for the wax crystallites to build over with a mechanism similar to that of paraffin wax crystal-modifiers. As asphaltene are polar in nature they are derived at the oil/water interface which was proved by the ability of asphaltene to reduce oil/water interfacial tension. Consequently, nucleation of the wax crystallites by asphaltene and resins at the interface will add to the thickness of the oil-water interfacial film and hence increase the stability of the emulsion.     

Influencing factors governing paraffin wax deposition of heavy oil and research on wellbore paraffin remover

Abstract

Wax deposition is harmful to oil wells, especially for waxy heavy oils at low temperature. The influencing factors on wax deposition of heavy oil were studied and a kind of O/W emulsion type wellbore wax remover was investigated. The results showed that the wax deposition rate of Jinghe heavy oil increased with the increasing wax content and asphaltenes content but decreased with the increasing water content. The oil in water emulsion type paraffin remover was prepared and it showed both good wax dissolution and paraffin prevention ability and can save large quantities of solvent. The results of this study provides a possible way for waxy heavy oils to dissolve wax, to prevent wax deposition and reduce the viscosity of heavy oils by emulsification together, which is helpful to reduce the frequency of hot washing and enhance oil recovery for waxy heavy oils.     

Stability of oil-in-water emulsions by SDS compound

Abstract

Surfactants are often required to reduce emulsion viscosity and heavy-oil flow resistance in pipelines, thereby forming a stable oil-in-water emulsion under shear stress. This study aimed to quantitatively discuss and analyze the stability of oil-in-water emulsions and characterize them through the initial viscosity change rate K. The value of K was obtained based on the oil-rich-phase viscosity curves of oil-in-water emulsions comprising sodium dodecyl sulfate (SDS), heavy oil, and water at different time points. Results showed that a smaller K corresponded to a more stable emulsion according to analysis of the effect of the compound system on emulsion stability and the synergistic mechanism. We then combined with 1-pentanol and octyldecyl glucoside (APG0810) with SDS. Results showed that the K values of the emulsions decreased from 19.457 to 6.284, and 19.457 to 5.834, respectively, after mixing 6% 1-pentanol and 0.4% APG, respectively, with 0.14% SDS. Then, 0.14% SDS was compared with 1.2% a mass fraction of each of the three additives to form a compound system, and the K values were found to follow the trend K_{1-pentanol/SDS} > K_APG/SDS. Thus, the stability of APG/SDS oil-in-water emulsion was better than that of 1-pentanol/SDS emulsion.     

PARTITIONING OF ALKYLPYRIDINES BETWEEN SHALE-DERIVED MIDDLE DISTILLATE FUEL AND WATER

ABSTRACT

A nitrogen-rich shale-derived middle distillate fuel was selected for the study of the partitioning of alkyl pyridines with water of pH 5. This particular middle distillate fuel, was found to contain acid extractable compounds composed mainly, about 90%, of alkyl substituted pyridines. The pyridine content of the extracts was determined by combined capillary column GC/HS. The partitioning was observed to be acid dependent.