不同有机溶剂对新疆油砂沥青的组成性质影响

油砂作为一种非常规石油资源,越来越受到人们的重视。油砂沥青的含量和性质对其开发有着重要的影响。有机溶剂抽提可以测定油砂沥青的含量。本文研究了3种溶剂对新疆油砂的抽提能力,并对不同溶剂抽提得到的新疆油砂沥青进行了性质分析。结果表明,新疆油砂含油率（甲苯测）为11.75%,属于中品位油砂矿;甲苯、氯仿和石油醚3种不同溶剂对新疆油砂沥青进行抽提,发现3种溶剂抽提能力的大小关系为氯仿＞甲苯＞石油醚;抽提过程中,氯仿表现出对胶质和沥青质较强的萃取能力,而石油醚对沥青质的萃取能力几乎为0,采用氯仿可以更准确地测定油砂沥青的含量。氯仿抽提得到新疆油砂沥青及其组分的杂原子含量和分子量高于甲苯和石油醚抽提的。由红外谱图发现,氯仿抽提得到的油砂沥青的含氧、含硫官能团的吸收峰强度大于甲苯和石油醚抽提的,表明氯仿对油砂沥青中极性物质的抽提能力更强。     

Effect of molecular weight and charge density on the performance of polyacrylamide in low‐grade oil sand ore processing

The effect of charge density and molecular weight (MW) of partially hydrolyzed polyacrylamide (HPAM) polymers on their performance in processing low‐grade oil sand ores was investigated. Bitumen extraction and tailings settling tests were carried out and an atomic force microscope (AFM) was used to directly measure the bitumen‐solid and solid‐solid interaction forces. It was found that HPAM polymers with a low MW acted as dispersants in the bitumen extraction process, resulting in low bitumen recovery and slow tailings settling but improved froth quality. In contrast, the use of HPAM polymers with a high MW improved both bitumen recovery and tailings settling but deteriorated froth quality. To achieve high bitumen recovery and fast tailings settling, a HPAM polymer must have a low to medium charge density (～30%) and a high MW (17.5 million Daltons). A stronger clay‐bitumen adhesion force normally resulted in a lower bitumen recovery. Fast tailings settling was achieved in the presence of a strong solid‐solid adhesion force.     

Effect of clays and calcium ions on bitumen extraction from athabasca oil sands using flotation

A novel approach, based on the doping of rich estuarine oil sands with calcium and/or clays, was developed to study bitumen extraction. The batch flotation tests showed that the addition of either calcium ions up to 40 p.p.m., or kaolinite, illite and montmorillonite clays at 1 wt% of oil sands processed had marginal effect on bitumen recovery from the estuarine ores. A sharp reduction in bitumen recovery was observed only when calcium ions greater than 30 p.p.m. and 1 wt% montmorillonite clays were added together. While bitumen recovery correlated well with changes in water/air/bitumen contact angle, no correlation was found between bitumen recovery and measured zeta potential of clays or surface tension of the supernatants from the flotation slurry. The wettability of bitumen was identified as a key element in determining bitumen recovery. The aqueous solution analysis for calcium ions showed that most of the added calcium ions disappeared from the solution when montmorillonite clays were present. The addition of illite or kaolinite clays changed the calcium ion concentration in the slurry only marginally. Stronger adsorption of calcium ions on montmorillonite than on either kaolinite or illite is considered to be responsible for the increased bitumen wettability, and hence reduced bitumen recovery.     

Novel polymer aids for low‐grade oil sand ore processing

In the present study, a hybrid Al(OH)₃‐polyacrylamide (Al‐PAM) was synthesized and used in combination with a partially hydrolyzed polyacrylamide (HPAM) to process a low‐grade oil sand ore. It was found that Al‐PAM was capable to improve bitumen froth quality and tailings settling. But it led to deterioration in bitumen recovery due to the formation of large bitumen lumps during the bitumen extraction process. To resolve this problem, HPAM was added in combination with Al‐PAM as a dual system. The use of the dual system at a low dosage achieved a holistic improvement in bitumen recovery, froth quality, and tailings settling. To understand the role of Al‐PAM and the dual system in the bitumen extraction process, bitumen‐clay, bitumen‐bitumen, and clay‐sand interaction and adhesion forces were directly measured using an atomic force microscope (AFM). The measured forces indicate that bitumen recovery and tailings settling are controlled by the colloidal interaction and adhesion forces between the oil sand components.     

Comparative study of three laboratory methods for the extraction of bitumen from oil sands

Measurements of total organic content and extractable bitumen for a number of different grade oil sands were used to obtain the extraction efficiency of several common bench-scale bitumen recovery techniques. The hot-water process was inefficient for feeds of moderate to high fines content. Soxhlet extraction and spherical agglomeration were found to be of similar efficiency for most grades of feed. For these two processes the efficiency is limited by the mineral fines content, probably because of surface absorption of bitumen components.     

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     

油砂沥青质对油砂沥青中甲苯残留的影响

利用热重质谱联用仪（TG-MS）分析了三种油砂沥青（印尼油砂沥青、伊朗油砂沥青、加拿大油砂沥青）中的甲苯残留以及油砂沥青质含量对油砂沥青中甲苯残留的影响,并在此基础上,进一步研究了油砂沥青质中的甲苯残留。结果发现,不同油砂沥青中甲苯残留量存在一定差异,其中印尼油砂沥青中的甲苯残留量最多。进一步对沥青质质量分数分别为10%、19%、30%的油砂沥青样品进行热重质谱实验,发现随着油砂沥青中沥青质含量的增加,甲苯的残留量会成倍增加。以加拿大油砂沥青质为例,研究了油砂沥青质对溶剂残留的影响,发现油砂沥青质具有对甲苯分子的夹带能力,导致甲苯分子在超过自身沸点40℃以上才能从沥青质中分离出来。油砂沥青中其他组分的存在也会加剧沥青质对甲苯的夹带作用。此外,研究还发现,在350~650℃时,油砂沥青质可以热解产生甲苯,而且油砂沥青中的沥青质含量越高,热解生成的甲苯越多。     

Kinetics of bitumen extraction from oil sands using organic solvents

The kinetic study of bitumen extraction from oil sands is significant for efficiency improvement and reactor design in industrial applications. Here, an improved pseudo-first-order kinetic model was established with the assumption of a constant Sherwood number, which took into account the mass transfer area. Five organic solvents were used for the extraction kinetics of the prepared bitumen microbeads. The improved pseudo-first-order kinetic model exhibited excellent fitting effects. Petroleum ether/dichloromethane was proved to be the best solvent. The results also showed an exponential decrease in the diameter of the bitumen microbeads and a linear increase in mass transfer coefficients with time for all the solvents. The kinetics of bitumen extraction from oil sands using different solvents were predicted according to the corresponding average mass transfer coefficients. The experimental results confirmed that the improved kinetic model was capable of describing the mass transfer process of bitumen extraction from oil sands.     

离子液体促进溶剂萃取油砂沥青

传统水洗法和溶剂萃取法萃取油砂沥青时,存在沥青中含有沙土和残沙中含有油等缺点。为解决上述缺点,本文采用不同比例的乙酸甲酯/正庚烷复合溶剂萃取油砂沥青,研究了离子液体（1-丁基-3-甲基咪唑四氟硼酸盐,[Emim]BF4）对该溶剂萃取体系的萃取率和分离洁净程度的影响。采用红外光谱仪和扫描电镜对萃取后的残沙和沥青的洁净程度进行了定性分析,并结合元素分析仪和电感耦合等离子体发射光谱仪获得萃取后残沙和沥青的洁净程度的定量结果。实验结果表明：当复合溶剂体积比为2∶3时,[Emim]BF4促使沥青回收率达到最大值94.20%,比单纯复合溶剂萃取体系的最大萃取率高7.92%;通过上述测试方法的定性和定量分析,证明了[Emim]BF4能有效解决沥青夹带沙土和残沙中含油的问题。     

水基提取技术用于油砂分离的研究进展

油砂作为一种重要的非常规油气资源,其分离技术的研究近些年来引起了国内科研工作人员的重视。介绍了目前世界上最重要的油砂分离技术--水基提取技术的基本原理及影响油砂分离的重要影响因素,阐述了油砂结构、特性与水基提取分离的重要关系及分离条件对沥青回收率的重要影响作用,同时探讨了原子力显微镜用于油砂水基分离过程中相关微观机理研究的重要应用,最后对水基提取技术用于油砂工业生产的流程进行了简单介绍。     

Determination of clay content in Canadian oil sands using x-ray florescence spectroscopy for diagnosis of ore processability

In this study, a simple and robust method based on the use of x-ray fluorescence (XRF) spectroscopy to measure potassium content as an indicator of illite in oil sands was proposed and tested. The XRF results of illite determination were compared with those determined using the conventional methylene blue titration (MBT) method. To test the suitability of the XRF method for determining illite content in various streams of oil sands processing as a diagnosis tool, a toluene-diluted-bitumen solution was used to contaminate solid surfaces prior to their analysis by the XRF and MBT methods. In order to remove the organic matter from the bitumen-contaminated solids for evaluating the XRF and MBT method, toluene washing and low temperature ashing were applied to the bitumen-contaminated solids prior to their analysis. The robustness of the XRF analysis in comparison with the MBT method was further confirmed by analyzing the solids extracted from bitumen froth and tailings stream. The results show that the XRF method was more tolerant to surface contamination and therefore more reliable in determining illite content in oil sands and relevant processing streams. It was also found that the potassium contents measured by the XRF method on solids from 10 ores show a strong correlation with the corresponding fines contents of these ores, indicating that the XRF method can potentially be used to determine the fines content of oil sands and related processing streams.     

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。     

Bitumen Recovery with Oily Air Bubbles

Air‐kerosene bubbles were used in a novel laboratory scale pipeline loop to assess the extraction performance of poor processing oil sand ores. The addition of kerosene to air, whereby producing oily bubbles, substantially enhanced bitumen recovery from poor processing oil sand ores. The oily bubbles were added in a pipeline loop during bitumen liberation from the sand grains. The bitumen recovery from poor processing ores with the addition of the oily bubbles to the conditioning slurry becomes comparable to that of good processing ores. The present findings can be of substantial benefit to the oil sands industry.     

Bitumen—sand interaction in oil sand processing

Bitumen—sand interaction was studied as a function of pH, particle size, temperature and solvent addition to bitumen. Sand particles can be easily detached from the bitumen surface at pH> 6. At pH < 6, strong attachment between bitumen and sand is observed. The bitumen—sand interaction is also particle-size dependent: the finer the particles, the stronger the attachment. The detachment of coarse particles from bitumen can be achieved by increasing the alkalinity of the solution, but not for fine particles, indicating that the particle size is one of the critical factors affecting liberation of bitumen from sand. Increasing temperature has two effects: it is not only reduces the viscosity to facilitate bitumen liberation, but also increases the electrostatic repulsion between sand and bitumen. This is confirmed by the DLVO theory and is in agreement with the batch extraction results on real oil sands.     

Conical filtering centrifuge for separation of solvent-diluted bitumen from oil sand mineral particles

The development of a continuous process for the separation of solvent-diluted bitumen from mineral particles is an important step for the development of solvent-based extraction technology of bitumen from mined oil sands. In this work, a custom-made conical filtering centrifuge is used to separate toluene-diluted bitumen from oil sand mineral particles. Compositions of wet granular samples are analyzed before and after centrifugation for three different oil sand ores. Results suggest that conical filtering centrifuges could be used for continuous separation of solvent-diluted bitumen from oil sand ores with relatively coarse particles.     

加拿大油砂沥青部分改质技术综述

介绍了加拿大油砂资源情况、主要性质、改质技术现状和原油外输能力,重点调研了有工业应用潜力的部分改质技术,包括工艺技术现状、核心流程、技术特点和存在问题等。从部分改质产品性质、改质深度、改质过程的碳排放强度、是否存在副产品等多种维度,分析油砂沥青部分改质技术的未来发展趋势。其中对油砂沥青进行缓和热裂解,或缓和热裂解结合沥青质脱除技术是油砂沥青部分改质的技术核心;目标是在满足加拿大管道要求的前提下,尽可能减少稀释剂用量、保证部分改质产品的稳定性,降低改质工艺过程的碳排放强度。