油砂沥青溶剂提取回收组合工艺

采用有机溶剂提取-超临界CO2回收溶剂这一组合方法对加拿大Athabasca油砂进行了提取分离及溶剂回收实验,通过实验筛选出最佳抽提溶剂为重整汽油。溶剂提取的最佳工艺条件:提取温度80℃,溶剂流量60mL/min,提取时间60min。在此条件下油砂沥青提取率达到92.74%。对超临界CO2-重整汽油体系的相行为进行研究,并通过实验综合考察了温度、压力、CO2流量以及回收时间等工艺操作条件对溶剂回收的影响。结果表明:在回收温度50℃,回收压力13MPa,溶剂与CO2分离温度70℃,压力5MPa,CO2流量7.5L/h,时间1h的条件下,重整汽油的回收率为98.71%。     

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。     

Displacement of bitumen from reconstituted oil sands by aqueous solutions

A simple method has been developed for modelling the recovery of bitumen from packed beds of oil sand by water or caustic solution displacement. Batches of reconstituted oil sand were prepared by intimately mixing predetermined amounts of sand, water, and bitumen, thereby permitting the composition of the oil sand to be controlled and varied within a wide range. Dilution of the bitumen with hexadecane facilitated the mixing process and allowed experiments to be performed at low temperatures while maintaining oil-water viscosity ratios comparable to those prevailing at the higher temperatures encountered during hot water or steam displacements in the field. The effects of a wide range of compositional and operational variables were studied using a two-level fractional factorial design technique and the findings are discussed. Of particular interest are the observations that the density and initial connate water saturation of the oil sand exert significantly more effect on bitumen recovery efficiency for the case of water displacement than for caustic solution displacement.     

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。     

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。     

On bitumen liberation from oil sands

Laboratory experiments were performed to investigate the effect of pH on (a) bitumen film thinning and film rupture process (b) bitumen/water contact line displacement and (c) the static contact angle of bitumen on a glass surface in the presence of an aqueous medium. A coated bitumen film on a glass surface was found to thin down and rupture spontaneously when a few drops of water having a pH of 11 was placed on it. In another experiment, a bitumen coated glass plate was submerged in water. The contact line of an initially circular bitumen film on the glass surface displaced in the inward direction to take the shape of a droplet. Measurement of the dynamic contact angle of bitumen with time showed that the bitumen/water contact line displacement was faster at a pH of 3 than at a pH of 11. However, the static contact angle of bitumen on the glass surface was found to be large at the high pH of 11, a condition conducive to easy detachment of bitumen droplet from the glass surface. The above observations suggest that a pH cycle might be desirable in bitumen liberation from oil sands.     

Wettability of fine solids extracted from bitumen froth

Production of synthetic crude oil from oil sands deposits in northern Alberta involves open pit mining, mixing the mined ore with water, extraction of aerated bitumen from the slurry, removal of water and solids from the froth formed, and upgrading heavy bitumen to liquid hydrocarbons. The success of the froth treatment operation, aimed at removal of fine solids and water from the bituminous froth, depends on the control of wettability of fine solids by the aqueous phase. Fine solids were extracted from bitumen froth by heptane. The partition of the extracted solids in aqueous, organic, and interphases was measured, and the wettability of the solids by water in various diluents was evaluated from contact angle measurements. The effect of diluent composition, sample drying, and surface washing on the wettability and fine particle partition was examined. The partition of fine particles correlated well with their wettabilities, and the results were found to be useful for interpreting the observations from froth treatment practice.     

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.     

加拿大油砂溶剂抽提分离工艺的研究

对加拿大油砂进行了溶剂抽提分离试验,考察了石油醚、石脑油、甲苯、环己烷以及重整汽油对提取效果的影响,确定重整汽油为最佳抽提溶剂.综合考察了提取温度、溶剂与油砂体积比、提取时间以及搅拌速度等工艺操作条件对油砂沥青提取的影响,结果表明,在提取温度500℃,溶剂和油砂的体积比为1∶1,提取时间60 min,搅拌速度为80 r/min的条件下,油砂沥青提取率达到92.57%.     

Study of fines in bitumen extracted from oil sands by heat-centrifugation

The temperature dependence of, first, the yield of bitumen extracted from oil sands and, second, of the coextracted solid particles in the bitumen was studied. Centrifugal extractions were performed in an argon (inert) atmosphere at temperatures ranging from 30 °C to 150 °C. The co-extracted solid particles were investigated through digital image analysis, instrumental neutron activation analysis and ash yield. The yield of bitumen increases with extracting temperature and is also dependent on the grade and origin of the oil sand. The quantity of fines, e.g. clay minerals or fine sand particles is dependent on the grade and origin of the oil sand. The total amount of co-extracted solid particles is found to be independent of the extracting temperature.     

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。     

表面活性剂强化重质油矿溶剂萃取残渣中残留溶剂鼓泡分离

针对重质油矿溶剂萃取残渣中残留溶剂的回收和去除问题,本文在鼓泡分离工艺的基础上提出了表面活性剂强化鼓泡分离工艺,探究了表面活性剂种类对于鼓泡分离过程的影响,并研究了阴离子表面活性剂十二烷基硫酸钠（SDS）对于鼓泡分离过程的动力学。结果表明,表面活性剂种类对去除效果具有重要影响：SDS可以通过降低甲苯-水界面张力和增加固体表面的亲水性,促进甲苯液层从固体颗粒表面的脱离,进而强化鼓泡分离过程,该过程符合一级动力学模型。然而,阳离子表面活性剂十四烷基三甲基溴化铵（C₁₄TAB）和双亲性表面活性剂月桂基甜菜碱（SB-12）则通过增加固体表面的疏水性,促使颗粒离开溶液体系,抑制了鼓泡分离的进行,但由于SB-12对固体表面改性的程度弱于C₁₄TAB,SB-12的抑制作用弱于C₁₄TAB,且随鼓泡时间的延长,SB-12对甲苯-水界面张力的改变成为影响鼓泡分离效果的主要因素,SB-12对鼓泡分离过程的影响由抑制转为强化,但C₁₄TAB在鼓泡分离过程中始终呈现抑制作用。上述结果对于类似的固相溶剂萃取后残留溶剂去除或回收具有一定的理论指导意义。     

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.     

Behaviour of the clay/bitumen/water sludge system from oil sands extraction plants

Rational waste management for large mineral extraction operations requires behavioural information and a clear understanding of processes. The behaviour of the clay/water/bitumen/sand systems at Syncrude Canada Ltd. is being studied. The macroscopic behaviour is becoming well understood, particularly with respect to the role of bitumen. The bitumen aids settlement, but hinders consolidation. Clay mineral behaviour in the presence of bitumen is unclear and remains worthy of detailed study, particularly with respect to the nature of the mineral/bitumen interface in the presence of various ions.Data are presented on system rheology, gel strength of sand/sludge mixes, the void ratio to permeability relationships for sludge, and the void ratio/effective stress relationship for sludge. Of considerable interest are the data at extremely low stresses, less than 1.0 kPa, as the great majority of water is expelled below this stress value.     

Distribution of clay minerals in the process streams produced by the extraction of bitumen from Athabasca oil sands

This study investigates the affinity of clay minerals in oil sands for the water‐continuous tailings and hydrocarbon‐continuous froth streams produced from the extraction of bitumen from oil sands. Clay minerals in oil sands processing impact bitumen flotation in separation vessels, emulsion formation during froth treatment, and fine tailings behaviour. X‐ray diffraction of oriented clay slides and random powder samples were used to quantify the clay minerals in the oil sands ore and process streams. Particle size distribution and clay activity balances were also conducted around the extraction process. The degree of partitioning during the conditioning and flotation stages in a batch extractor was determined by the surface properties of the clay minerals present. The water‐continuous tailings stream was further separated into fine and coarse tailings fractions through sedimentation. The bulk of the clay minerals reported to the fine tailings stream. Illite and mixed layered illite‐smectite partitioned less to the hydrocarbon‐continuous froth than kaolinite. Also, the illite‐smectite in the froth stream appeared to be different from the illite‐smectite in the water continuous streams.