Analysis of Solvent‐Diluted Bitumen from Oil Sands Froth Treatment Using NIR Spectroscopy

Process control and optimization of bitumen froth treatment during oil sands processing require rapid analysis of asphaltene content in bitumen, solvent‐tobitumen ratio (S/B), and the density of solvent‐diluted bitumen. NIR spectroscopy was employed to meet this requirement. The NIR system comprised a spectrometer with no moving parts coupled with a double‐pass transflectance probe via a fiber‐optic cable. Quantitative calibration models were established using partial leastsquares regression in latent variables. The standard errors of calibration were 0.20 wt% for 0 to 20 wt% asphaltenes in bitumen, 1.1 wt% for 20 to 100 wt% asphaltenes in bitumen, 0.1 for S/B of solvent‐diluted bitumen, and 0.0017 g/mL for density of solvent‐diluted bitumen. It was shown that the process conditions could be monitored through the spectral scores from principal component analysis.     

Clay minerals in nonaqueous extraction of bitumen from Alberta oil sands: Part 1. Nonaqueous extraction procedure

A non-aqueous bitumen extraction process was studied where only toluene and heptane, with no water additions, were used to extract bitumen from two Alberta oil sands ore samples. One sample had a high bitumen (13.5 wt.%) and low fines (5.3 wt.% < 45 μm) contents, while the other sample had an intermediate bitumen (10.5 wt.%) and high fines (23.3 wt.%) contents. Bitumen recovery and product quality were measured under different process conditions such as the ratio of toluene to heptane and settling time. The Dean Stark procedure was used to determine the solids, bitumen and water contents of the extraction products. In addition, the water content was determined by the Karl Fischer titration method. High bitumen recovery was obtained for both oil sands ore samples although the high fines ore sample was more sensitive to the extraction conditions, especially the toluene to heptane ratio. A product with high purity, containing more than 99.5 wt.% bitumen on a solvent-free basis, was produced at room temperature under the optimum extraction conditions tested. The optimum settling time to achieve a pure product was less than 10 min, based on solids and water contents in the supernatant.     

Effect of weathering on oil sands processability

Effect of weathering on oil sand processability was studied using a good processing ore, a laboratory weathered ore and a naturally weathered ore. The laboratory weathered ore was prepared by weathering the good processing ore in an oven under controlled conditions to study the nature of ore weathering. It was found that the bitumen recovery, bitumen flotation rate, and bitumen froth quality were greatly reduced due to ore weathering. It was also observed that the fresh bitumen coating on a silicon surface could recede and liberate from the silicon surface easily even in a warm water of 35°C. However, after weathering of the bitumen coating, its liberation became more difficult and effective liberation of bitumen from the silicon surface could only occur at higher temperature of 65°C. The current study further confirms that weathering enhanced adhesion of bitumen with solids, causing difficulties for bitumen liberation from sand grains and hence poor processability of weathered ores.     

Solvent extraction of athabasca oil-sand in a rotating mill Part 1. Dissolution of bitumen

Solvent extraction of bitumen from oilsands in a rotating contactor is described. A mass transfer model, derived by Phillips et al., has been used to calculate relative mass transfer coefficients under different operating conditions. Bitumen derived hydrocarbon fractions, such as naphtha and kerosene, have been found to be adequate solvents only when partially preloaded with bitumen. This improved solvency may be ascribed to an enhanced aromatic content as a result of the bitumen addition. Under appropriate conditions complete solution of bitumen, even in weak solvents, can be made to occur in less than two minutes.     

Solvent screening for non‐aqueous extraction of Alberta oil sands

Non‐aqueous extraction of bitumen from oil sands has the potential to reduce fresh water demand of the extraction process and eliminate tailings ponds. In this study, different light hydrocarbon solvents, including aromatics, cycloalkanes, biologically derived solvents and mixtures of solvents were compared for extraction of bitumen from Alberta oil sands at room temperature and ambient pressure. The solvents are compared based on bitumen recovery, the amount of residual solvent in the extracted oil sands tailings and the content of fine solids in the extracted bitumen. The extraction experiments were carried out in a multistage process with agitation in rotary mixers and vibration sieving. The oil sands tailings were dried under ambient conditions, and their residual solvent contents were measured by a purge and trap system followed by gas chromatography. The elemental compositions of the extraction tailings were measured to calculate bitumen recovery. Supernatants from the extraction tests were centrifuged to separate and measure the contents of fine solid particles. Except for limonene and isoprene, the tested solvents showed good bitumen recoveries of around 95%. The solvent drying rates and residual solvent contents in the extracted oil sands tailings correlated to solvent vapour pressure. The contents of fine solids in the extracted bitumen (supernatant) were below 2.9% for all solvents except n‐heptane‐rich ones. Based on these findings, cyclohexane is the best candidate solvent for bitumen extraction, with 94.4% bitumen recovery, 5 mg of residual solvent per kilogram of extraction tailings and 1.4 wt% fine solids in the recovered bitumen. © 2012 Canadian Society for Chemical Engineering     

A novel method for the management of sulfone-rich waste produced in the oxidative desulfurization (ODS) process

The oxidative desulfurization (ODS) process is one of the new desulfurization processes for the production of clean fuels. Despite the benefits of the ODS process, this process faces several important challenges. One of the most important challenges of this process is the management of a waste which is rich of sulfone compounds. In the present study, a new strategy which is the addition of waste to the bitumen with other solid waste such as high density polyethylene (HDPE) waste has been investigated. The experimental design method was applied to investigate the effect of addition of the sulfone and HDPE wastes to the properties of the bitumen blends including degree of penetration, softening point, and mass loss. It was found that the sulfone waste can be added to the bitumen as a softener. The results showed that several grades of bitumen including 50/60, 60/70, 85/100 can be produced through the addition of sulfone waste along with the HDPE waste to the base 60/70 bitumen. In general, the application of simple processes such as mixing the wastes with the bitumen can reduce the cost of waste management, considerably.     

印尼油砂沥青的净化工艺

溶剂萃取法分离油砂制得油砂沥青中含大量机械杂质,影响沥青的品质及后期加工利用。通过XRD和激光粒度仪表征了机械杂质的矿物组成和粒度分布等特性。针对机械杂质的特性,开发了复配试剂,通过稀释剂降黏沥青、复配试剂净化沥青、稀释剂回收再生及循环利用3个操作单元对油砂沥青进行了脱杂净化实验,并分析了净化机理。结果表明：降黏过程,温度70℃、时间10min、稀释剂与沥青比0.3g/g,稀释沥青70℃黏度为3.2Pa·s;净化过程,6%盐酸与稀释沥青比0.2mL/g、CaCl₂与稀释沥青比0.01g/g,温度70℃,混合时间10min,沉降时间20min,机械杂质脱除率可达到93.5%;回收及循环过程,稀释剂回收率为98%,循环使用5次,机械杂质脱除率仍92%以上。该工艺具有沉降时间短、机械杂质脱除彻底的优点。     

A novel method for the management of sulfone-rich waste produced in the oxidative desulfurization (ODS) process

The oxidative desulfurization (ODS) process is one of the new desulfurization processes for the production of clean fuels. Despite the benefits of the ODS process, this process faces several important challenges. One of the most important challenges of this process is the management of a waste which is rich of sulfone compounds. In the present study, a new strategy which is the addition of waste to the bitumen with other solid waste such as high density polyethylene (HDPE) waste has been investigated. The experimental design method was applied to investigate the effect of addition of the sulfone and HDPE wastes to the properties of the bitumen blends including degree of penetration, softening point, and mass loss. It was found that the sulfone waste can be added to the bitumen as a softener. The results showed that several grades of bitumen including 50/60, 60/70, 85/100 can be produced through the addition of sulfone waste along with the HDPE waste to the base 60/70 bitumen. In general, the application of simple processes such as mixing the wastes with the bitumen can reduce the cost of waste management, considerably.     

Impact of fines content on a warm slurry extraction process using model oilsands

Natural oilsands deposits are composed of a complex mixture of sand, silt, clay, water and bitumen. The bitumen content and silt fraction, or fines (<44 μm), have traditionally been used as primary measures of ore processability. However, it is now known that this rule of thumb is not always applicable. In fact, the variability of oilsands, in terms of both quality and composition, makes it difficult to determine the unbiased effect of any individual component on bitumen extraction from mined ore. To address this problem, a model oilsands (MOS) system has been devised to determine how the interactions of oilsands components affect bitumen recovery. In this preliminary work, the effects of bitumen and fines contents, connate water pH and sodium hydroxide (NaOH) dosages on primary bitumen recovery were determined under the conditions extant in the warm slurry extraction process (WSEP). A three-factor Box-Behnken experimental design was used to quantify the effects. Prior to incorporation into the model oilsands system, each component was characterized to ensure quality control between tests. For the simple model studied in this work, the fines content and sodium hydroxide addition were the most important parameters affecting primary bitumen recovery. Although a small amount of fines was required to recover bitumen in the absence of process aids, an excess of fines was always detrimental to bitumen recovery.     

水辅助溶剂法提取油砂中的沥青

开发了一种水辅助溶剂法从油砂中提取沥青的技术。该方法通过在油砂固相与有机溶剂间介入水层提取油砂中的沥青。以内蒙古扎赉特旗油砂矿为研究对象,考察了温度、剂砂质量比、提取时间、甲苯在复合溶剂中的含量及溶剂的种类与性质对沥青回收率高低的影响,结果表明：最佳提取条件为提取温度50℃,剂砂质量比1∶1,提取时间25min。沥青回收率与提取溶剂的性质紧密相关,水层介入有效降低了固体微粒组分在有机相中的含量,且便于后续的有机相与泥砂相的分离。通过对各种溶剂提取的沥青进行组分分析,发现各种溶剂对沥青提取能力的差异性源于溶剂的化学组成和结构不同。本文相关研究结果对溶剂法提取油砂中沥青技术及溶剂种类的选择具有指导作用。     

Synthesis and Properties of Fumaric Copolymers as Potential Bitumen Modifiers

New copolymers of dioctyl fumarate (DOF) and styrene (S) were synthetized by radical polymerization and used to modify bitumen. The poly(dioctyl fumarate-co-styrene) copolymers, PFS, were characterized by ¹H-NMR and FTIR spectroscopies and size exclusion chromatography (SEC) in order to determine their monomer composition and weight average molecular weights, respectively. The polymer-bitumen blending conditions were optimized and the samples analyzed by different methodologies. Fluorescence microscopy, rotational viscosity and differential scanning calorimetry (DSC) were used to study the morphological changes of blends during their manufacturing and the rheological and thermal behavior, respectively. All modified bitumen (MB) exhibited higher viscosity than the based bitumen (BB) under studied conditions and this effect was more evident for the MB containing the higher molecular weight polymer. The addition of polymers to BB enhances the bitumen viscosity and thus increased the energy required for the flowing (activation energy calculated by Arrhenius equation). Thermal and morphological analysis showed that all MB exhibited good polymer- bitumen compatibility, which could be consider as a good starting point for a potential applications of this new material in road engineering.     

Processibility of Athabasca Oil Sand Using a Laboratory Hyd ro t ransport Extraction System (LHES)

A novel laboratory scale apparatus has been developed and used to assess the extraction performance of oil sands under conditions analogous to current industrial processes. The apparatus can be used to investigate independently, the liberation of bitumen from the sand as well as air‐bitumen attachment and bitumen recovery. Experiments show that lower operating temperatures have a detrimental effect on bitumen recovery and controlled air addition is beneficial for recovery. The liberation of bitumen from sand grains has been found to proceed faster than air attachment and bitumen recovery, making the flotation the ratelimiting step in the extraction process. The potential benefit of staged air injection into hydrotransport pipelines as a possible process aid is discussed.     

Recovery of the molybdenum catalyst for fossil fuel hydrogenation

The composition and the properties of molybdenum-containing residues remaining after catalytic hydrogenation of coals and bitumen were studied. The chemical and the mineralogical composition of the products and the forms of molybdenum compounds were established. The techniques of concentration of molybdenum compounds (flotation, magnetic separation, and oxidative sublimation of MoO₃) were considered.     

Structure and artificial ageing behavior of organo montmorillonite bitumen nanocomposites

This paper studied the structure and ageing behaviors of bitumen modified with organo montmorillonite (OMt). Two OMt with different surfactants were used to modify one base bitumen using a laboratory high-shear mixer. The rolling thin film oven test and the pressure air oven test were performed to simulate the short term (ST) and long term (LT) ageing on the bitumen, respectively. The structures of OMt were determined by X-ray diffraction, fluorescence microscopy and computed tomography (CT) scanning. The ageing behaviors were evaluated with a dynamic shear rheometer. The intercalated structure of both OMt was observed in the bituminous matrix. This structure improved the ST ageing behaviors of bitumen. With respect to the LT ageing, an automatic accumulation of OMt particles took place under the tough artificial ageing conditions, and consequently led to a less improvement in the ageing behavior.     

油砂沥青超声波减粘工艺研究

油砂沥青粘度较大,自然状态下不易流动,严重影响了管道输送及加工,针对目前油砂沥青研究中存在的问题,采用超声波进行了减粘的实验研究。实验综合考察了超声波作用时间、温度、超声波频率、超声波功率等因素对减粘效果的影响。实验结果表明,在适当的超声作用时间(20 min)、适宜的温度(30℃)、适宜的超声波频率(20 kHz)和超声波功率(250 W)的条件下,油砂沥青的减粘率可达80%以上。经超声波处理后的油砂沥青粘度略有恢复,但仍远低于处理前的粘度,超声波减粘效果良好。     

基于废旧轮胎胶粉的热塑性弹性体的制备及发泡性能研究

通过沥青改性胶粉及采用相容剂与聚丙烯共混制备了性能优良的热塑性弹性体(TPE)材料,并以超临界流体为发泡剂对其发泡性能进行了研究。实验结果表明,胶粉通过沥青改性后,可以明显地提高TPE的拉断伸长率,并且发泡TPE的泡孔平均直径增大,泡孔密度减少,相对密度减小,但是随着沥青用量的增加,材料的粘度降低,从而出现泡孔破裂和塌陷现象,最后导致泡孔平均直径和泡孔密度减小,相对密度增加。相容剂苯乙烯嵌段共聚物接枝马来酸酐(SEBS-g-MA)可以提TPE的拉断伸长率并改善泡孔结构。温度的升高和饱和压力的增大,都导致了发泡弹性体的泡孔增大,泡孔密度和相对密度减小。     

The effect of bitumen molecular fractions on diffusivity and rheology of bitumen under high-temperature conditions: Molecular dynamics (MD) simulation study

Heavy oil and bitumen play an incredible role in Canada's energy resources. The main processes that have already been applied to produce heavy oil and bitumen are in-situ thermal methods. The primary mechanism of production in these reservoirs is a reduction in heavy oil and bitumen viscosities via heat transfer. Having deep knowledge about the rheological behaviour of heavy oil and bitumen is crucial to designing a more accurate and efficient in-situ thermal recovery method. In this work, molecular dynamics (MD) simulation was used to model the rheological behaviour of bitumen under different temperatures. According to MD outputs, the highest diffusion coefficient between bitumen fractions belongs to saturate fractions. On the other hand, the lowest diffusion coefficient belongs to asphaltene fractions. The size of asphaltene, its polarity, and the polarity of a resin fraction affect the diffusion coefficient of asphaltene in a bitumen sample and its rheological behaviour. The MD simulation aims to provide molecular insights and essential information about the rheological trend of bitumen under different thermodynamic conditions. The results of the current work provide essential information about the effect of bitumen fractions on its rheological behaviour.     

Rheological properties of bitumen modified with ethylene butylacrylate glycidylmethacrylate

This article presents experimental results related to rheological viscoelastic properties of polymer modified bitumens, PmBs. Experiments were performed by a dynamical shear rheometer before and after thermo‐oxidative aging. Two types of bitumens with different asphaltene contents were modified by the addition of two types of reactive ethylene terpolymers, Elvaloy AM, and Elvaloy 4170, with a different percentage of reactive functional group, glycidylmethacrylate, GMA. Results of the investigation indicate that the degree of reactive polymer modification is a function of bitumen type, bitumen‐polymer compatibility, and polymer concentration. Polymer modification improves the following physical properties of the base bitumen: penetration, softening point, temperature susceptibility, and elastic recovery. Reactive polymers are effective binder modifiers that improve the susceptibility to high temperature of asphalt mixes, and also their rutting resistance, contribute to their good storage stability and make them less sensitive to aging. This is a result of the formation of a chemical bond between the polymer and molecules of asphaltenes. POLYM. ENG. SCI., 54:1056–1065, 2014. © 2013 Society of Plastics Engineers     

Role of mineral flotation technology in improving bitumen extraction from mined Athabasca oil sands: I. Flotation chemistry of water‐based oil sand extraction

The role of surface hydrophobicity in water‐based oil sand extraction is examined from the perspective of mineral flotation separation. Although anionic carboxylates (sulphonates) released from bitumen are helpful for charging bitumen and liberating bitumen from sand grains, their presence in oil sand slurries tends to make bitumen and bubbles less hydrophobic. In addition, solid hydrophobization under oil sand extraction conditions can occur through different mechanisms of carboxylate adsorption. It is the hydrophobized fine solids that present challenges for achieving a high bitumen recovery with a good froth quality, due to their competition with bitumen for attachment to bubbles. While chemisorption of carboxylates contributes to hydrophobization of heavy minerals present in oil sands, carboxylate adsorption activated by hydrolyzed metal cations alters silica and clays from hydrophilic to hydrophobic. Different adsorption mechanisms of calcium on silica, clays, and other minerals are analyzed to explain why fine solids of varying mineralogy in combination with calcium affect bitumen extraction differently. Metal ions that activate solid hydrophobization under oil sand extraction conditions are identified from dynamic attachment of solids from mature fine tailings (MFT) to bitumen. To mitigate the effect of fines on oil sand extraction, selective flocculation of fine solids is recognized as especially feasible for bitumen flotation recovery from oil sand middling streams. Future research in reducing or eliminating caustic addition, understanding the role of inorganic anions, and searching for feasible techniques for treating MFT based on different mineralogy and surface properties, are briefly discussed.

     

Supercritical fluid extraction of bitumens from Utah oil sands

The supercritical fluid extraction (SFE) of bitumens from four major Uinta Basin (Utah) oil sand deposits was studied with propane solvent. The deposits studied included Whiterocks, Asphalt Ridge, PR Spring and Sunnyside. The bitumens from these deposits differed widely in physical and chemical properties. The volatilities (components with boiling point <811 K) were 46.6, 53.5, 45.4 and 40.9 wt.%; the molecular weights were 653, 426, 670 and 593 kg/kg mol; and the asphaltene contents (n-pentane insolubles) were 2.9, 6.8, 19.3 and 23.6 wt.% for the Whiterocks, Asphalt Ridge, PR Spring and Sunnyside bitumens, respectively. The SFE experiments were carried out at five conditions, combinations of three different pressures (5.6 MPa, 10.4 MPa, and 17.3 MPa) and three temperatures (339 K, 380 K and 422 K). The cumulative extraction yield increased with increase in solvent density at all operating conditions for the four bitumens. A maximum yield of 45 wt.% was obtained at the highest solvent density with the Whiterocks bitumen. The extraction products were significantly upgraded liquids relative to the bitumens. Comparatively lighter fractions were extracted in the earlier stages of extraction for all the four bitumens, whereas heavier extracts were obtained at higher extraction-solvent densities. The asphaltene contents of the residual fractions were significantly higher than the asphaltene contents predicted on a prorated basis for all four bitumens. This trend was due to the extraction of cosolubilizing components that kept the asphaltenes in suspension in the bitumen. It was concluded that solute polarity played a significant role in the extraction yields of the four bitumens. The Whiterocks bitumen, which was the least polar bitumen based on asphaltenes content, gave higher extraction yields compared to the bitumens from the other three deposits at all five operating conditions. The Sunnyside bitumen with the highest asphaltene content gave the lowest extraction yield at all five conditions. The Asphalt Ridge and PR Spring bitumens with intermediate polarity (based on asphaltene content) gave intermediate extraction yields with the Asphalt Ridge bitumen extraction yields higher than the PR Spring bitumen. Preliminary modeling of the extraction process using the Peng–Robinson cubic equation of state and a pseudocomponent lumping scheme provided a reasonable match with the experimental data for Whiterocks and PR Spring bitumens.