Fine Solids Research Articles

Chemical, Magnetic and X-Ray Diffraction Studies of the Sediments from Oil Field in Argentina

Chemical, magnetic, and phase composition analysis of deposits taken from sedimentation tank from oil plant in Argentina was carried out. Energy dispersive spectroscopy indicates iron as a main sediment component with the site dependent fraction ranging from 11% to 78% (weight percentage). Moreover, large fractions of sulfur (4%‐33%), oxygen (8%‐28%), calcium (1%‐14%), and silicon (1%‐11%) were found. The chemical analysis performed with wet chemical methods also indicated Fe as a main component (about 35%), additionally a large fraction (… 15%) of the sulfur and under 10% fractions of calcium (… 7%), carbon (… 6%), and silicon (… 5%) were found in the sample. The phase composition studies performed using X-ray diraction showed magnetite — Fe3O4, goethite — fi-FeOOH, lepidocrocite — ∞-FeOOH, siderite — FeCO3, and iron‐sulfur compounds (mackinawite — FeS, stoichiometric FeS, greigite — Fe3S4) and other compounds like aragonite — CaCO3, calcite — CaCO3, anorthite — CaAl2Si2O8, quartz — SiO2 and barium sulphate Ba(SO3)0:3(SO4)0:7. Studies performed by the Mossbauer spectroscopy, confirmed presence of majority of compounds identified by X-ray diraction. Magnetic AC susceptibility measurements show that magnetite is a main component of the studied deposit. High concentration of the magnetic compounds deposited in the sedimentation tank points to the advisability to install the magnetic device designed to support water treatment processes, i.e.: flocculation, coagulation, sedimentation, and filtration. This device could simultaneously inhibit microbiological and chemical corrosion. The oil structurally trapped in a typical reservoir (a rock formation that contains hydrocarbons) can be produced either under its own pressure (a primary production process) or under applied external pressure by water injection (a secondary production process). Because of low productivity of the primary recovery process, the secondary recovery technologies are essential. In the water flooding recovery technique the oil is displaced by water from the reservoirs and moved via porous rock formation towards the wells. The obtained water-in-oil emulsion contains dispersed fine solids which penetrate the oil during production process. The production stream is passed through separation equipment to separate oil, gas, water, and suspended solids. The separated oil is recovered and the separated water is reinjected into the reservoir rocks as additional flooding water. The suspended solids are deposited in the sedimentation tank. Not suciently purified water (containing dispersed solids) can be responsible for the loss of the rock permeability caused by particles trapped in small pores [1]. Water injection stimulates the productivity of oil reservoirs, but a consequence may be an increase of microbiological and chemical corrosion. The mixture of oil and water provides favorable growth conditions for sulphate

The Multi-Sized Slurry Flows in Horizontal Pipes : Innovated Models and Verification

Although multi-sized particles slurries are transported in practical pipelines, most reported correlations were proposed for single-size slurries. If the average diameter of solids is used to estimate the drag coefficient of multi-sized particles slurries, the hydraulic gradients with these correlations lead to considerable scatter of data . Kazanskij , Moro , and STSJ (Slurry Transport Society of Japan) [4] summarised some empirical equations of hydraulic gradient of slurry flow with experimental data. The Wasp method [5] recommended by Liu [6] has been used by designers of pipeline systems for predicting hydraulic gradient of compound slurries of homogeneous and heterogeneous flows. However, the method is limited for application to a wide range of transport conditions. Kaushal et al. [7] also discussed the limitations and attempted to modify the method. They concluded that the Wasp method provided reasonable accurate results at limited low concentrations. The purpose of this paper is to discuss the limitations of application of other researchers' correlations and to develop innovated models, based on the single-size slurry model of Seitshiro et al. [8] The analytical models depend on particle size distribution: (1) coarse-coarse model; for a slurry consisting of two fine particles in high concentration. The fine solids are defined as particles with sizes smaller than the critical diameter [9] in this study. For both models, it is assumed that the coarse solids in the slurry do not hinder each other's movements. Experiments were performed in a 1-inch transparent pipe with sand-bakelite mixed slurries. The data of Shook et al. , Boothroyde et al. , and that of this study were used to verify the application of the models. The analytical results suggest that the innovated models can be effective for designing slurry pipelines.

Fish meal replacement by plant protein substitution and guar gum addition in trout feed. Part II: Effects on faeces stability and rheology

In the explosively growing aquaculture industry, the challenge of sustainability includes a requirement to produce more fish than are consumed by stock. A promising avenue of research is the substitution of the fish meal in feeds with plant protein. However, there are inherent risks in the development of such feeds, and serious consideration should be given not only to nutritional content, but also to the mechanical quality of resulting faecal wastes. The present study uses a plate on plate rheometer running in different flow modes (creep, oscillation) to assess the rheological properties of wastes resulting from different diets.All faeces were shown to be thixotropic in nature, independent of diet composition. Details of dietary composition influence the consistency and the characteristic stresses at which faecal structure changes from a viscoelastic solid into a viscoelastic liquid. Furthermore, in linking active food components with mechanical properties of chyme faeces, rheological studies may be used to understand and counteract some problematic properties. Substituting 100% of fish meal with plant proteins leads to faeces that rapidly disintegrate into very fine solids which threaten the viability of aquacultural operations. Adding just 0.3% of the rapidly hydrating non-starch polysaccharide, guar gum (GG), significantly increased the viscosity and elastic modulus of the faeces. These mechanical improvements increase the size of the resulting particles and the effectiveness with which they can be removed, thereby leading to optimized water quality. GG addition was sufficiently effective to counter the stability and particle size effects of a 50% substitution of fish meal, but could not mitigate those of a 100% substitution, wherein dissolution effects of an unknown emulsifier are suspected.

Sample Preparation Method for Characterization of Fine Solids in Athabasca Oil Sands by Electron Microscopy

This study introduces a new sample preparation method for characterization of fine solids in Athabasca oil sands using electron microscopy. The method uses a combination of microtome and focused io...

Role of Dissolving Carbon Dioxide in Densification of Oil Sands Tailings

Carbon dioxide (CO2) was shown as a promising alternative for oil sands tailings treatment with economical and environmental benefits. This study aims to understand the role of CO2 addition in densification of oil sands tailings. In this study, CO2 was pressurized into two industrial whole tailings provided by Syncrude Canada Ltd. and Canadian Natural Resource Ltd. The optimal initial settling rate, supernatant clarity and solids content of sediment were achieved at a CO2 partial pressure of about 100 kPa. The improvement on densification of oil sands tailings by CO2 was mainly attributed to pH reduction under various CO2 partial pressures. The zeta potential of fines became less negative with decreasing pH, enhancing coagulation of fine solids. On the other hand, CO2 bubbles formed by dissolved gas under supersaturation pressure led to a less clear supernatant by disturbing the formed sediments. Supersaturation with nitrogen was applied to the oil sands tailings to verify the influence of dissolved gas o...

Improving Oil Sands Processability Using a Temperature-Sensitive Polymer

A temperature-sensitive polymer, poly(N-isopropylacrylamide), was tested as a process aid to process a low-grade, high-fines oil sand ore. Two sets of bitumen extraction tests were carried out. In test set I, both oil sands slurry conditioning and bitumen flotation were conducted at 23 °C. In test set II, the slurry was conditioned at 23 °C, and, however, the bitumen flotation step was carried out at 40 °C. It was found that the use of the polymer in test set I imposed a negative impact on both bitumen recovery and bitumen froth quality. In test set II, the addition of the polymer at the bitumen extraction step improved bitumen recovery and significantly accelerated solids settling of the tailings but deteriorated the bitumen froth quality. The improvement in bitumen recovery and tailings settling at the higher operating temperature was attributed to the change of the polymer from a long, extended structure to a coiled configuration, resulting in the formation of compacted floccules of fine solids. Atomic force microscopy (AFM) was used to directly measure the long-range interaction and adhesion forces of fine solids-bitumen in industrial process water. Results from the AFM force measurements indicated potential slime coating of fine solids on bitumen, thus providing a scientific basis on the reduced bitumen froth quality with the polymer addition.

The Influence of Initial Carbonate Concentration on the Folin-Ciocalteu Micro-Method for the Determination of Phenolics with Low Concentration in the Presence of Me-thanol: A Comparative Study of Real-Time Monitored Reactions

During the Folin Ciocalteu (F-C) micro-assay for the determination of phenolics in the presence of methanol, fine solids can form. In a previous paper, we hypothesized that the interference from alcohol on the F-C reaction can be minimized depending on the particular procedure used to reach the alkalinity condition. In order to demonstrate our hypothesis we studied, by spectrophotometrically monitoring, the time-behaviour of the reactions carried out in the presence of different methanol concentrations at the same alkalinity condition from two protocols. The results showed that the interfering effect of methanol on the F-C micro-method can be affect and even prevented depending on working conditions. In particular, the formation of fine solids can be delayed, slowed down and prevented depending on the initial carbonate concentration used. We have explained why the initial carbonate concentration, used to reach the final alkalinity condition, plays an important role in the F-C reaction carried out in the presence of methanol. Moreover, the results from real-time monitoring showed that, differently from traditional F-C procedure, our procedure allows us to carry out the F-C micro method in the presence of 6% methanol, as an extreme concentration, reading the absorbance at real time 24 min. The real-time monitoring of absorbance can be considered as a useful means to explore the effect of other parameters on precipitate formation caused by the presence of methanol in the F-C reaction.

Iron-rich Oklahoma clays as a natural source of chromium in monitoring wells

Water samples, drawn from groundwater monitoring wells located southeast of Oklahoma City, OK, were found to contain elevated concentrations of total chromium with an apparent source localized to the area surrounding each well. Since these monitoring wells are located in areas with no historic chromium usage, industrial sources of chromium were ruled out. Water testing was performed on twelve monitoring wells in the area that historically had elevated total chromium concentrations ranging from 10-4900 micrograms per litre. Filtered water samples were found to be free of chromium contamination, indicating that the source of the chromium is the suspended solids. Analysis of these solids by acid digestion and a sequential extraction technique revealed that the chromium was primarily associated with iron-containing solids. X-ray diffraction identified goethite, an iron oxide hydroxide, as the dominant iron-containing phase in the suspended solids. The mineralogy in this region is dominated by interbedded red-bed sandstone and mudstone whose mineral content includes mixed-layer illite-smectite, hematite, goethite, gypsum and dolomite. Elemental analysis of soil samples collected as a function of depth in the locale of the monitoring wells indicated that the iron rich clays contain a natural source of chromium. The elevated levels of total chromium are most likely due to the dissolution of silica and alumina from the chromium containing iron clays in the basic well water, resulting in the release of fine suspended solids that naturally have high chromium concentrations. These results should be applicable to other areas containing iron-rich clays.

Concentration of Liquid Feed in Hydrocyclone to Reduce Drying Energy Use

The use of a hydrocyclone is proposed to concentrate the liquid feed such as slurry or diluted suspension prior to thermal drying. The hydrocyclone of special design, called a CANMET hydrocyclone, allows partial separation of three-phase systems such as fine solids suspended in an oil–water emulsion. Thus, when combined with a dryer, preconcentration of the solid–liquid suspension in a hydrocyclone makes it possible to reduce thermal load to the dryer and therefore to lower energy consumption for water evaporation, which translates into reduced emissions of greenhouse gases. This article presents the design characteristics and operational features of the CANMET hydrocyclone and evaluates drying energy savings in a hybrid system built on this hydrocyclone and a convective dryer.

Use of carbon dioxide stripping for struvite crystallization to save caustic dosage: performance at pilotscale operationPaper submitted to the Journal of Environmental Engineering and Science.

The feasibility of stripping CO2 from anaerobic digester centrate (generated in a sludge dewatering process) to raise pH, and therefore reduce the cost of caustic chemical(s) dosage for similar operation in a struvite-recovery system, was investigated. A cascade CO2 stripper was installed in a pilot-scale, struvite-recovery reactor system at the Lulu Island Wastewater Treatment Plant, Richmond, British Columbia, Canada, as a replacement of part of (about 1/3) the reactor downpipe. Centrate was used as the process feed. Both the influent and the effluent from the struvite reactor were analyzed for pH, temperature (°C), and concentrations of Mg, NH4-N, and PO4-P. Results indicated that, by adding the CO2 stripper, caustic chemical savings was as much as 46%–65%. Moreover, because of the capability of the stripper in providing a more gradual pH increase, fewer fine solids were produced in the reactor than when caustic solution was used to raise the pH of the reactor.

Sintering of Fine Particles in Suspension Plasma Sprayed Coatings.

Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating’s microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. Previous experimental studies carried out for plasma sprayed titanium oxide and hydroxyapatite coatings enabled us to observe either a finely grained microstructure or, when a different suspension injection mode was used, to distinguish two zones in the microstructure. These two zones correspond to the dense zone formed from well molten particles, and the agglomerated zone formed from fine solid particles that arrive on the substrate in a solid state. The present paper focuses on the experimental and theoretical analysis of the formation process of the agglomerated zone. The experimental section establishes the heat flux supplied to the coating during deposition. In order to achieve this, calorimetric measurements were made by applying experimental conditions simulating the real coatings’ growth. The heat flux was measured to be in the range from 0.08 to 0.5 MW/m2, depending on the experimental conditions. The theoretical section analyzes the sintering during the coating’s growth, which concerns the fine particles arriving on the substrate in the solid state. The models of volume, grain boundary and surface diffusion were analyzed and adapted to the size and chemistry of the grains, temperature and time scales corresponding to the suspension plasma spraying conditions. The model of surface diffusion was found to best describe the sintering during suspension plasma spraying. The formation of necks having the relative size equal to 10% of particle diameter was found to be possible during the thermal cycles occurring at the coatings’ deposition. Transmission electron microscopic observations of the agglomerated zone hydroxyapatite coating confirm the sintering of some of the fine grains.

Mechanical properties of suspension plasma sprayed hydroxyapatite coatings submitted to simulated body fluid

Home synthesized (HA) powder was formulated with water and alcohol to obtain a suspension used to plasma spray coatings onto titanium substrate. The deposition process was optimized and the resulting coatings were soaked in simulated body fluid (SBF) for the periods of 3, 7, 14, 28, and 60 days at controlled temperature of 37 °C. The microstructural research enabled to find in the as-sprayed deposits two characteristic zones: (i) dense zone corresponding to the lamellas, observed usually in thermally sprayed coatings; (ii) sintered zone containing fine hydroxyapatite grains corresponding to the fine solids from initial suspension. The sintered zone disappears after soaking in SBF and the pores get filled by the reprecipitated calcium phosphates. The adhesion of the soaked coatings to the substrate was characterized by the critical load in the scratch test and was about 10 to 12 N. The Young modules of the coatings were determined with help of depth-sensing indentation test by the use of the technique developed by Oliver and Pharr. The modules were not depending on the time of soaking and their mean values were 15.6 and 28.4 GPa, depending on the coating operational parameters. The scratch test enables to determine the hardness of the coatings, which remained fairly constant during the time of soaking in the range of 3 to 5 GPa. This hardness was compared to that the Martens microhardness which doubled with time of soaking to reach up to 1 GPa.

Waxy Crude Oil Emulsion Gel: Impact on Flow Assurance

In oilfield operations, the formation of crude oil emulsions is very common and can cause significant flow assurance problems during oil production. These emulsions can be very stable as a result of the presence of polar compounds, such as asphaltenes and resins, that play the role of natural surfactants and also because of the occurrence of many types of fine solids that can form resistant films at the crude oil/water interface. Gelled waxy crude oil flows have been largely studied, and the effect of dispersed water on crude oil rheology has been well-characterized; however, little attention has been given to the potential impact of waxy crude oil emulsion gel formation. In this study, it is shown that in some waxy crude oils the presence of water above a threshold value could promote gel formation, significantly changing the viscosity of the mixture. The rheological properties of waxy crude oils were determined at different water cuts, temperatures, and shear rates, and also a chemical characterization ...

Phase evolution of hydroxapatite coatings suspension plasma sprayed using variable parameters in simulated body fluid

Abstract Fine, hydroxyapatite (HA) powder, synthesized using calcium nitrate and diammonium nitrate was formulated with water and alcohol to obtain a suspension used to plasma spray coatings onto titanium substrates. The deposition process was optimized using statistical design of 2 n experiments with two variables: spray distance and electric power input to arc plasma. The sprayed coatings were soaked in simulated body fluid (SBF) for the periods of 3, 7, 14, 28, and 60 days at controlled temperature of 37 °C. The reference intensity ratio (RIR) method basing onto X-ray diffraction (XRD) data was used to determine quantitatively the phase composition of as-sprayed and soaked deposits. Electron probe microanalysis (EPMA) enabled to make the profiles of calcium to phosphorus atomic ratio along a line though the coatings' cross sections. Raman spectroscopy of selected samples enabled to localize the different crystal phases in sprayed coatings. The coatings included some porosity and have two characteristic zones: (i) dense zone corresponding to the lamellas, observed usually in thermally sprayed coatings; (ii) sintered zone containing fine hydroxyapatite grains which correspond to the fine solids from the suspension which were agglomerated in the cold regions of plasma jet and sintered on the substrate. The soaking in SBF homogenizes the morphology of coatings. The sintered zone disappears and the pores get filled by the reprecipitated calcium phosphates.

EVIDENCE FOR DUST CLEARING THROUGH RESOLVED SUBMILLIMETER IMAGING

Mid-infrared spectrophotometric observations have revealed a small sub-class of circumstellar disks with spectral energy distributions (SEDs) suggestive of large inner gaps with low dust content. However, such data provide only an indirect and model-dependent method of finding central holes. Imaging of protoplanetry disks provides an independent check of SED modeling. We present here the direct characterization of three 33-47 AU radii inner gaps, in the disks around LkHa 330, SR 21N and HD 135344B, via 340 GHz (880 micron) dust continuum aperture synthesis observations obtained with the Submillimeter Array (SMA). The large gaps are fully resolved at ~0\farcs3 by the SMA observations and mostly empty of dust, with less than 1 - 7.5 x 10^-6 Msolar of fine grained solids inside the holes. Gas (as traced by atomic accretion markers and CO 4.7 micron rovibrational emission) is still present in the inner regions of all three disks. For each, the inner hole exhibits a relatively steep rise in dust emission to the outer disk, a feature more likely to originate from the gravitational influence of a companion body than from a process expected to show a more shallow gradient like grain growth. Importantly, the good agreement of the spatially resolved data and spectrophotometry-based models lends confidence to current interpretations of SEDs, wherein the significant dust emission deficits arise from disks with inner gaps or holes. Further SED-based searches can therefore be expected to yield numerous additional candidates that can be examined at high spatial resolution.

Understanding weathering of oil sands ores by atomic force microscopy

AbstractEffect of weathering on colloidal interactions between bitumen and oil sands solids was studied by atomic force microscopy (AFM). The change in bitumen chemistry due to weathering was found to have a negligible effect on the interactions of bitumen with solid particles. However, the increase in solid surface hydrophobicity due to ore weathering reversed the long‐range interaction forces between bitumen and solids from repulsive to attractive with a corresponding increase in adhesion force. The measured force profiles between bitumen and various solids can be well fitted with the extended DLVO theory by considering an additional attractive force. The attractive long‐range force and increased adhesion force make the separation of bitumen from solids more difficult and the attachment of fine solids on liberated bitumen easier, thereby leading to poor bitumen liberation and lower aeration efficiency. Such changes account for the observed poor processability of the weathered ores. © 2009 American Institute of Chemical Engineers AIChE J, 2009

Problems affecting nitrification in commercial RAS with fixed-bed biofilters for salmonids in Chile

The present case study focused on the problems that affect the nitrification process at three commercial recirculating aquaculture systems (RAS) for salmonids with fixed-bed biofilters operating in Chile, where the main factors were found to be management problems: (1) large variations in daily feeding, which results in unstable nitrogenous compounds (TAN, NO2−, NO3−) concentration; (2) variable daily water exchange, producing unstable culture conditions (variations in pH and temperature); (3) high densities of culture, which results in overall bad culture conditions (high CO2 concentration, high amount of fine solids, high oxygen consumption). When properly managed, the RAS have proven to tolerate up to 15% of daily variation in feeding, as low as 10% of daily “new” water inlet, and densities as high as 60kgfish/m3 without showing any nitrification problems. The results from this study demonstrates that maintaining good water quality is essential to secure an efficient growth of both the target species and the nitrifying bacteria, therefore, the production strategies should consider both the target species and the nitrification process requirements.

Interaction of Chloride Salts and Kaolin Clay in the Hydrolysis of Emulsified Chloride Salts at 200–350°C

The hydrolysis of chloride salts is an increasing problem in the refining of heavy crude oils and bitumens. The contributions of kaolin clay as a potential contaminant were evaluated by steaming mixed chloride salts and kaolin clay in a base oil. The amount of chloride released from the oil mixture increased from 1.21% to 4.50% with addition of clay. The same trends were observed with pure salts. By providing a large surface for deposition of salts from emulsified brine droplets, the fine solids in the oil increased the extent of reaction of chloride salts with steam.

Effect of Solid Wettability on Processability of Oil Sands Ores

The wettability of mineral solids and bitumen isolated from nine different Athabasca oil sands ores was determined to establish its role in water-based extraction of bitumen from oil sands. The processability of oil sands ores was determined using Denver flotation tests. The contact angle of a water drop on a bitumen-coated silica wafer was measured using the sessile drop method. For fine solids (<45 μm), the water drop penetration time was measured on a surface of a compressed disk of fine solids. For coarse solids (106−250 μm), the wettability of solids was evaluated by determining the partitioning of the solids between an oil and a water phase. It was found that the processability of different oil sands ores varies significantly in term of bitumen recovery, bitumen froth quality, and bitumen froth morphology. The wettability of bitumen, on the other hand, does not significantly depend on the source of oil sands ores. However, the wettability of the fine and coarse mineral solids is ore-dependent, which...

Composition and particle size of superparamagnetic corrosion products in tap water

Chemical analyses, magnetization, Mössbauer spectrum, and x-ray diffraction measurements were made on solids removed from tap water by means of membrane filters. The taps from which this water was obtained had previously been unused for prolonged periods of time. When these taps were reactivated and water was first drawn, it was observed that the quantity of coarse solids in the water gradually decreased with flow, while at the same time the quantity of fine solids gradually increased. The magnetization, Mössbauer spectra, and x-ray diffraction patterns of the solids showed the presence of a significant number of superparamagnetic particles of magnetite. In the temperature range of our measurements (77 K < T < 300 K), paramagnetic iron-based species, particularly lepidocrocite, were also present in the solids. Contaminants such as Pb, Cu, and As were observed to be present in significant amounts, and it is shown that these are adsorbed to the magnetic nanoparticles. It was observed that almost all of the solid particles could be removed by means of 5-μm filters. This removal process can be explained by means of a model which assumes that initial deposition of coarse aggregates of corrosion products on the filters forms a coating, rich in extremely fine iron oxides. The coating has a high capacity for sorption of very small individual particles.