Understanding bitumen partial upgrading through process modelling and simulation

Partial upgrading is an emerging direction in the processing of Canadian oil sands bitumen in response to the economic and environmental challenges in the oil sands industry. Partial upgrading aims to improve bitumen quality only to the level at which pipeline specifications are met without use of diluent. Given that partial upgrading technologies have not yet reached commercial deployment, there is a lack of technical data to assess the expected benefits in terms of energy input and greenhouse gas emissions reduction. In this study, we present an assessment of a partial upgrading scheme using detailed process simulation. We developed a conceptual process scheme considering visbreaking, solvent deasphalting, and naphtha hydrotreating as the core partial upgrading processes. Reactor models were assembled using experimental data from CanmetENERGY's pilot plant facilities and from the literature and integrated into a plant‐wide simulation model. Simulations allowed the examination of trends in partial upgrader product yields and quality and enabled a comparison with traditional bitumen upgrading.     

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。     

A new kinetic model for pyrolysis of Athabasca bitumen

Pyrolysis of bitumen is a key contributor to gas production in in situ combustion and in situ gasification recovery processes, yet a detailed reaction scheme, that includes a breakdown of products into the most abundant gas components, that is simple enough to be used in detailed thermal‐reactive simulation models, does not exist. Here, we present a novel reaction scheme for pyrolysis of Athabasca bitumen that was developed and calibrated against four experimental data sets (65 data points) over a temperature range from 130 to 422°C. The new model was then verified by comparing its thermogravimetric behaviour against published literature. © 2012 Canadian Society for Chemical Engineering     

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.     

浆态床重油改质技术新进展

浆态床加氢工艺是一种重要的劣质重油/渣油轻质化技术,随着原油的劣质化和产品的清洁化,其重要性凸显,各大石油公司均大力研究和开发。本文重点介绍了典型浆态床加氢工艺(包括Eni公司的EST、Chevron公司的VRSH、UOP公司的UniflexTM等)的技术特征和进展情况。在详细分析浆态床加氢反应机理的基础上,指出了其未来的研究方向:研究重油反应过程的胶体稳定性以控制生焦;开发新型高效催化剂以降低成本;研究浆态床反应器流体力学和传质特性以指导工程放大。     

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。     

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.     

天然沸石基微介孔复合催化剂的制备及其油砂沥青减黏改质性能

利用水热稳定性高的天然斜发沸石为铝源,水玻璃为硅源,Na OH为碱源,十六烷基三甲基溴化铵为模板剂,稀硫酸调节p H,再经过老化、晶化、烘干和焙烧等制备具有微介孔复合结构、良好水热稳定性和高比表面积的clin/MCM-41催化剂。将p H=10和硅铝物质的量比100条件下制得的催化剂应用于蒸汽辅助重力泄油技术开采的加拿大油砂沥青改质反应。在剂油质量比1∶10和310℃反应30 min条件下,减黏率超过90%,同时大量胶质和沥青质非烃被催化裂化为轻质油,表明clin/MCM-41催化剂是优异的油砂沥青中低温减黏催化剂。     

Thermo‐physical properties of n‐pentane/bitumen and n‐hexane/bitumen mixture systems

The gravity drainage as a result of viscosity reduction is the main governing mechanism of the solvent‐aided thermal bitumen recovery processes. Therefore, the density and viscosity of the diluted or heated bitumen are essential to predict the oil production rate. In this paper, we report thermo‐physical properties of n‐pentane/bitumen and n‐hexane/bitumen mixtures. The density and viscosity of Athabasca bitumen diluted with n‐pentane and n‐hexane were measured at different temperatures (30 to 190 °C), pressures (2 to 8 MPa), and solvent mass fractions (0.05 to 0.5). Various correlations and mixing rules proposed in the literature were examined to calculate the density and viscosity of the diluted bitumen. This study proposes appropriate mixing rules and generalized parameters for predicting the density and viscosity of solvent‐bitumen systems. Our findings will find applications in the design and simulation of heavy oil and bitumen solvent‐aided thermal recovery processes.     

Phase behaviour modelling of Athabasca bitumen for in situ combustion applications

Phase behaviour modelling of reservoir fluid is a fundamental step for reservoir simulation. Furthermore, as the complexity of the recovery process increases, the fluid model plays a more important role in the reliability of the simulation outputs. Although the in situ combustion enhanced oil recovery method (ISC) is one of the most complex recovery techniques available in the petroleum engineering literature, for most of the simulation jobs related to this elaborate process only simple and rudimentary fluid characterization layouts are considered. In this work, the principal fluid properties of Athabasca bitumen with regard to the ISC process are recognized, extracted from the literature, validated for consistency, and used for the development of an inclusive and accurate fluid model. Then the fluid model is fully developed while considering the ISC reaction kinetics so that the model has both accuracy, indispensable for phase behaviour modelling, and consistency, essential for the reactions definitions.     

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.     

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。     

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。     

Organic coated solids in athabasca bitumen: Characterization and process implications

Bitumen, separated from oil sands by the hot water extraction process, contains ultra‐fine (< 200 nm), inorganic solids (BS). Surfaces of BS particles are coated with toluene insoluble organic matter (TIOM). This organic material is polar and aromatic with contributions from both humic and asphaltene‐like components. Although the surfaces of BS particles are dominated by TIOM, the coverage is patchy rather than continuous. As a result, these solids are capable of stabilizing fine water emulsions in the bitumen phase. The nature of the organic matter on the surfaces of the particles is such that it has a high propensity to form coke. Therefore, these particles can also play a role in fouling on equipment and catalysts.     

Ethyl acetate as a bio-based solvent to reduce energy intensity and CO2 emissions of in situ bitumen recovery

We introduce ethyl acetate (EA), a bio-based chemical, as a potential solvent for bitumen recovery through comprehensive phase behavior and numerical simulation studies. Phase behavior and thermophysical properties of EA/live bitumen are measured at temperatures and pressures up to 190°C and 4 MPa, respectively. Experimental studies suggested that coinjection of EA with steam can reduce the bitumen viscosity by several orders of magnitude. Our numerical simulations show that coinjection of 2–8 mol% EA with steam can significantly reduce the steam-oil-ratio (SOR) by almost 0.9 units while increasing the bitumen production rate. This reduction in SOR can be translated to significant energy saving of ~2.2 GJ, emission reduction of ~120 kg of CO₂, and wastewater reduction of ~120 m³ per ton of the produced bitumen, which are almost 20–25% lower than the steam-assisted gravity drainage (SAGD) process.     

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。     

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.     

Modelling and parameter estimation of ultra-dispersed in situ catalytic upgrading experiments in a batch reactor

In situ catalytic upgrading of heavy oil and bitumen has been suggested and tested in the laboratory for utilization of heavy oil resources. Experimental observations have demonstrated potential, so this innovative recovery technique may have a role in the development of large resources of heavy oil and bitumen. Accurate analytical and numerical modelling is necessary in order to correctly interpret experimental measurements of the in situ upgrading, leading to a better understanding and design of field-scale processes. In this paper, we present modelling and parameter estimation for ultra-dispersed catalytic upgrading experiments conducted in a batch reactor. The Monte Carlo simulation technique was used to estimate the most appropriate reaction parameters. The combination of an analytical batch reactor model and the Monte Carlo simulation technique allows for the fast generation of a large number of upgrading experiment realizations. Comparisons of analytical modelling results with the experimental measurements of the upgrading experiments at different temperatures are in close agreement. Results reveal that ultra-dispersed catalytic upgrading in a batch reactor results in a fairly high residue conversion and can potentially increase the API gravity of the produced oil.