Process intensification for heavy oil upgrading using supercritical water

Demand for light hydrocarbons has been steadily increasing in the market with a corresponding decrease in heavy hydrocarbon demand. Therefore, there is a need to develop environmentally friendly and efficient technologies for conversion of heavy molecular weight hydrocarbons. Supercritical fluids (SCF) are attracting increased attention as solvents for green chemistry and among those supercritical water (SCH₂O) is promising for the upgrading of heavy hydrocarbons. Because of a sharp decrease in its dielectric constant, water loses its polarity when brought to the supercritical conditions and its properties starts to resemble the properties of hydrocarbons and becomes an excellent solvent for organic compounds. Moreover, increased ionic product of water leads to an increasing [H₃O⁺] concentration and thus promotes the reactions requiring the addition of an acid. Solvation power enables the extraction of lighter compounds while increased [H₃O⁺] concentration makes the reactive extractions of heavy hydrocarbons possible. As a result of its favorable properties, a wide variety of process intensification studies have been carried out using near critical or SCH₂O such as combined distillation-cracking-fractionation and in some cases even without the utilization of catalysts and/or hydrogen. In this review, recent advances on reactions of hydrocarbons occurring in a SCH₂O environment will be highlighted. Fundamental aspects of these reactions including their thermodynamics and kinetics will be discussed. Experimental and theoretical developments on phase equilibria of relevant water–hydrocarbons systems will be presented.     

Preparation of Co–Mo supported multi-wall carbon nanotube for hydrocracking of extra heavy oil

In this study, multi-wall carbon nanotube (MWCNT) supported Co–Mo nanocatalysts with changes in synthesis steps, one and two-step, were prepared through impregnation to be used in extra heavy oil hydrocracking process. In both of the synthesized nanocatalysts, the Co/Mo weight ratio was 1/3. The nanocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and accelerated surface area and porosimetry (ASAP) methods. The results showed that the nanocatalysts prepared through a two-step impregnation method had higher surface area and pore volume than the other synthesized nanocatalysts.The nanocatalysts were used in hydrocracking process under mild operating conditions, 260–300 °C and at H₂ initial pressure of 5 MPa. Hydrocracking of extra heavy oil was conducted in an autoclave reactor. The results indicated that both nanocatalysts were capable of hydrocracking heavy oil at mild operating conditions. However, the nanocatalysts synthesized through the two-step impregnation exhibited higher performance, better heavy oil to light oil conversion, and better sulfur removal than the other methods. This superiority is due to the nanocatalyst's structure and better distribution of metal clusters on the support.     

埕北稠油催化改质降粘实验研究

室内评价埕北稠油催化改质降粘的实验效果,筛选出最优改质降粘催化剂,考察催化剂用量、反应温度、反应时间、供氢剂种类及用量对稠油改质降粘的影响。结果表明,采用有机酸锰催化剂和甲苯供氢剂,在催化剂用量为稠油质量的0.10%、反应温度240 ℃、反应时间24 h、水油质量比1∶3和甲苯用量为稠油质量的5%条件下,稠油粘度由2 740 mPa·s降至780 mPa·s,改质降粘率达到71.5%。     

Review of processes for downhole catalytic upgrading of heavy crude oil

Unlike conventional refinery processing, downhole upgrading involves implementing catalytic processes in oil-bearing geologic formations. In this way impurities contained in heavy crude oil can possibly be left in the ground or easily separated during oil production, providing an improved crude oil feed for refineries. Additionally, value or viability can be added to an otherwise uneconomic or remote heavy oil deposit. In order to successfully produce improved quality oil via a downhole upgrading project, several processing steps are anticipated: placement of catalysts into an appropriate downhole location, mobilization of reactants over the catalyst bed, and creation of processing conditions necessary to achieve a reasonable degree of catalytic upgrading. Each of these steps has been proven by past application; their combination into a unified below-ground process remains problematic. Downhole processing differs from surface processing in that brine, high steam partial pressures and low hydrogen partial pressures need to be accommodated in the downhole setting. There are no reports of significant downhole catalytic upgrading of crude oil, although examples of thermal upgrading are noted. However, available technology should be amenable to conducting a successful process. Upgrading of heavy crude oil at anticipated downhole processing conditions has been successfully proven in the laboratory. Recently published literature with immediate pertinence to the problems of downhole catalytic upgrading is reviewed with the goal of stimulating research and providing directions for future investigations.     

Pyrolysis oil upgrading by high pressure thermal treatment

High pressure thermal treatment (HPTT) is a new process developed by BTG and University of Twente with the potential to economically reduce the oxygen and water content of oil obtained by fast pyrolysis (pyrolysis oil), properties that currently complicate its co-processing in standard refineries. During the HPTT process, pyrolysis oil undergoes a phase split yielding a gas phase, an aqueous phase and an oil phase. In this study, HPTT experiments were carried out at different operating conditions in a continuous tubular reactor. Experimental results showed that, with increasing temperature and residence time, the release of gases (mainly CO₂) and the production of water increased, reducing the oxygen content of the oil phase and hence increasing the energy content (from 14.1 to 28.4 MJ/kg) having the temperature a larger effect when compared to the residence time. Using gel permeation chromatography (GPC), an increase of the molecular weight of the oil phase, probably due to polymerisation of the sugars present in pyrolysis oil, was observed. When water was added as solvent to dilute the feed oil, a decrease of the molecular weight of the resulting oil phase was observed. This indicated that the concentration of organic components had a direct effect on the formation of high molecular weight components. In conclusion, during HPTT an oil with lower oxygen and water content with higher energy value was produced, but adverse formation of high molecular weight components was also detected.     

Pipeline flow behaviour of heavy crude oil emulsions

Pipeline transportation of heavy oils as oil-in-water emulsions has been proposed as an alternative to blending the crude oil with natural gas condensate or other diluent. An 18 m long, 0.02 m I.D. closed loop was constructed to investigate the behaviour of an emulsified Cold Lake crude oil under pipeline flow. Pressure drop was measured as a function of flow rate for freshly produced emulsions to establish correlations of friction factor versus Reynolds number. Stability was observed for long term pipeline flow. The time at which the emulsion breakdown occurred was found to be a function of oil concentration and shear rate. The breakdown of the emulsion was clearly indicated by a simultaneous change in the system variables of pressure drop, temperature and power required to turn the pump at constant speed.     

供氢剂辅助重油热改质技术研究进展

重油高黏度和高密度的特点给重油开采、集输和加工带来极大不便,一般都要先对其进行降黏处理。供氢热裂化是在传统减黏裂化基础上加入供氢剂,以改善减黏裂化加工深度不大、装置易生焦、产品安定性差等问题的一种高效重油改质降黏技术。文章首先介绍了重油管输技术基本类型,然后从供氢剂的供氢机理、供氢剂加入的作用、供氢剂的基本类型、供氢剂可供氢量的计算方法和供氢剂的运用等方面进行了综述。对于供氢剂的选择需要根据工艺条件和供氢剂性质等方面综合分析。指出在不生焦的前提下,尽可能提高改质苛刻度可有效提升重油改质效果,而影响生焦和抑制结焦的关键在于来自供氢剂的活泼氢能否及时封闭沥青质自由基。     

稠油地下改质开采技术及发展趋势

稠油作为全球重要的非常规原油资源,是保障我国能源安全、重大工程需求的重要资源。目前常规的热采稠油油藏陆续进入开采后期,高能耗、高污染、高成本问题日趋严重,亟需依靠技术换代实现开发方式升级。稠油地下改质是通过向油藏中注入改质催化剂,使其与稠油发生化学反应,实现稠油地下不可逆降黏并高效采出的一种开采方式,是近十年来最受瞩目的下一代稠油开采技术之一。本文从技术机理、改质催化剂及开采效果影响因素三方面阐述了技术内涵,通过系统调研国内外相关学者和企业的代表性成果,按照催化剂种类、反应温度和降黏效果等进行综合性分类统计,对比了现有矿场试验的开采方式和采油效果,指出制约技术应用的两个关键问题,并展望了技术未来发展方向。     

稠油石油酸盐及其对稠油乳化降粘应用研究

以辽河稠油为原料,采用脱酸剂法,对稠油中的石油酸进行抽提,然后分离出石油酸盐回注到稠油中,进行乳化降粘。考察了复合萃取剂用量、抽提相分离温度、相分离时间、脱酸剂油比、碱酸摩尔比及萃取次数等因素对抽提酸效果的影响。确定了抽提酸的最佳工艺条件:复合萃取剂用量60%,碱酸摩尔比1.0,剂油比2.0,80℃保温分相2 h,在该条件下,分三级萃取,环烷酸抽提效率达到92.20%,脱酸剂收率可达96.18%;并测试了石油酸盐对稠油的乳化降粘性能,结果表明,稠油石油酸盐与其它表面活性剂进行简单复配,对辽河稠油和渤海稠油等环烷基或中间基稠油有明显的乳化降粘效果,降粘率分别达到90%和80%以上,具有较好的适用性。     

Effect of extra virgin olive oil on glycaemia in healthy young subjects

In this approach we studied the glycaemia levels in 20 healthy young volunteers (26 ± 2 years), before and after a 30‐day intake of 50 mL of extra virgin olive oil (EVOO). We selected an oil rich in phenolic compounds (523 mg/L) with a high content of secoiridoidic derivatives (over 94.5%). The findings from our study reveal a significant decrease of glycaemia from 89.6 ± 6.8 to 82.7 ± 10.3 mg/dL (p<0.05), related to a long term daily intake of the study EVOO, as the only added fat. A significant increment of the HDL cholesterol, from 68.7 ± 11.5 to 75.2 ± 4.9 mg/dL, was also highlighted. Total cholesterol, LDL, VLDL, triglycerides, and blood pressure did not show significant variation after the 30‐day consumption of this EVOO. So far, few articles have described the influence of EVOO consumption, on plasma glucose levels in humans. This effect is observed in a group of healthy young humans. Moreover, we confirm that the level of free hydroxytyrosol (OH‐Tyr) in plasma increased up to fourfold (p<0.05) after the 30‐day intake of this EVOO. In addition, the excretion in urine of the main metabolite of OH‐Tyr, homovanillic acid (HVA), significantly increased.     

微波作用下二硫代氨基甲酸盐脱除重质原油中的镍钒

研究了微波强化作用下二硫代氨基甲酸盐NS系列化合物对新疆重质原油的脱镍钒效果.合成了具有—CSS—配位基团的NS系列化合物,该系列产物分子结构中—CSS—配位基团,可以与原油中的镍和钒发生配位反应形成水溶性化合物从而从原油中脱除.对于原油脱镍钒效果为NS3 >NS2 >NS4 >NS1,在微波强化作用下NS3脱镍钒剂对原油脱镍钒的实验表明,NS3加入量为200mg/L,微波时间为3min,微波功率为700W,反应温度为90℃和反应时间为20min的条件下,原油中镍和钒的脱除率分别为79.8%和82.4%,微波强化作用后原油的脱镍钒效率增加.     

草浆黑液降低稠油粘度的研究

将碱法制浆黑液与稠油混合，可明显降低稠油的粘度．用均匀设计法设计试验，讨论了黑液浓度、稠油酸值、水油比（体积）、温度及水的矿化度对稠油降粘作用的影响．结果表明，黑液浓度为5％～15％，酸值为3～4.5mg／g（KOH／油）时，体系粘度最低，在试验范围内，水油比越大，温度越高，矿化度越小体系的粘度越低．     

塔河油田超稠油水溶性减阻降粘剂的研究与应用

针对塔河稠油高粘及油田地层水高矿化度的特点,研制了耐盐型稠油减阻降粘剂,考察了药剂浓度、矿化度、油水比例以及破乳效果等对稠油降粘效果的影响。结果表明,在A剂加量为3 200 mg/L,B剂加量为800 mg/L,w(油)∶w(水)=6∶4时,降粘剂最佳适用矿化度为9×104mg/L左右,对破乳基本无影响。现场试验结果表明,稠油减阻降粘剂能满足50℃时原油粘度在50×104mPa.s以下的稠油降粘,其对矿化度敏感,最佳矿化度使用范围在7×104~12×104mg/L,耐盐型稠油减阻降粘剂应用于电泵型油井降粘试验效果较好。     

Characterization of medium and heavy crude oils using thermal analysis techniques

This study focused on the characterization of heavy and medium grade crude oils in limestone matrix using differential scanning calorimeter (DSC) and thermogravimetry (TG-DTG). DSC and TG-DTG curves produced for two different crude oils + limestone mixtures indicate that the crude oil undergoes two major transitions when subjected to an oxidizing and constant rate environment known as low- and high-temperature oxidation. Kinetic analysis in the low- and high-temperature oxidation regions were performed using two different kinetic methods. Throughout the study, it was observed that the activation energy values of the samples are varied between 2.40-10.62 and 42.3-181.9 kJ/mol in low- and high-temperature oxidation regions respectively.     

Crystallization and melting properties of extra virgin olive oil studied by synchrotron XRD and DSC

Crystallization and melting properties of triacylglycerols in extra virgin olive oil were studied by using synchrotron X‐ray diffraction (XRD) and differential scanning calorimetry (DSC). The phase transitions were monitored by cooling and heating the samples at 2°C/min from 60 to ?60°C and vice versa. Upon cooling, a first DSC endothermic peak was recorded at ?9.6°C followed by one at ?33.5°C. These thermal events were associated to the formation of two different structures: a triple‐chain length (3L) having a c parameter of about 58.38 Å and a quadruple chain length structure (4L) with a c parameter of about 89.99 Å, respectively. Both structures evidenced a cell packing arrangement ascribable to a β′ form. During heating, part of the metastable β′ crystals rearranged into the more thermodynamically stable β form. Then, upon further heating, the sequential melting of the two crystal structures was observed. The melting was completed at 10.7°C. Beside this interpretation of XRD data, a model considering a cell with a c parameter of about 170 Å and a hexagonal crystal system was proposed. Even if more research is needed to validate this approach, it allowed all XRD events recorded during the experiments to be described. See commentary by Chiavaro [p. 267–269], http://dx.doi.org/10.1002/ejlt.201200415     

稠油降粘输送室内研究

应用注蒸汽开采稠油中的水热裂解反应及稠油的降粘机理,将它应用到稠油集输过程中,通过实验找出较好的催化剂,从当中得出一些结论,可能被油田使用。     

注蒸汽条件下供氢催化改质稠油及其沥青质热分解性质

利用CWYF-Ⅰ型高压反应釜模拟热采条件下,以甲酸作为供氢体.以自制的油溶性有机镍盐为催化剂进行的稠油水热裂解反应.考察了供氢体的加入对催化水热裂解反应前后稠油黏度、族组成及硫含量的影响,并采用TG-DTA分析法对供氢催化改质反应前后稠油中沥青质的热转化行为进行了分析.结果表明,随着加入供氢体质量分数增加,供氢催化水热裂解后稠油降黏率增大,饱和烃、芳香烃含量增加,胶质,沥青质含量降低,同时硫含量下降.供氢催化水热裂解反应后的稠油中沥青质TG-DTA曲线分析表明,供氢催化水热裂解反应后稠油中沥青质失重量高于催化水热裂解反应前稠油中含有的沥青质的失重量.经过供氢催化水热裂解反应,稠油中沥青质的稳定性下降.     

Use of a dispersed iron catalyst for upgrading extra-heavy crude oil using methane as source of hydrogen

The use of an iron dispersed catalyst, derived from Fe₃(CO)₁₂, for extra-heavy crude oil upgrading using methane as source of hydrogen was studied. The upgrading reactions were carried out batchwise in a stainless-steel 300 ml Parr reactor with 250 ppm of Fe at a temperature of 410-420 °C, a pressure of 11 MPa of CH₄, and a residence time of 1 h. In the presence of Fe₃(CO)₁₂, the reaction of Hamaca extra-heavy crude oil led to a reduction of two orders of magnitude in the viscosity (from 500 to 1.3 Pa s), 14% reduction in sulfur content, and 41% conversion of the >500 °C fraction in the upgraded product with respect to the original crude. The iron catalyst was isolated from the coke produced from the upgrading reaction and was analyzed by XPS, EDAX, and Mössbauer spectroscopy. The results indicated the presence of a Fe-V mixed sulfide species with a composition ca. (Fe_0.6V_0.4)_zS, where z is in the range 0.8-0.9.