Concentrations and modes of occurrence of platinum group elements in the Shengli River oil shale, northern Tibet, China

The Shengli River–Changshe Mountain oil shale zone, located in the North Qiangtang depression, northern Tibet plateau, represents a potentially large marine oil shale resource in China. Twenty-one samples including oil shale, micritic limestone and marl were collected from the Shengli River area to determine the contents, distribution patterns and modes of occurrence of platinum group elements (PGEs) in marine oil shale. Oil shale samples from the Shengli River area have high ash yield (61.86–67.48%) and total organic carbon content (8.02–13.67%) with low total sulfur content (0.76–1.39%) and intermediate shale oil content (3.60–16.30%). The total PGE content in oil shale samples is very low (average 1.749 ng/g), approximately half the mean value of Chinese coals, but higher than that of USA coals. PGEs in oil shale samples from the Shengli River area are characterized by high Pd (average 0.82 ng/g), Os (average 0.15 ng/g) and Pt (average 0.66 ng/g) contents compared with Ru (average 0.05 ng/g), Rh (average 0.05 ng/g) and Ir (average 0.02 ng/g). Distribution patterns of individual PGEs are not uniform in the Shengli River oil shale section. The lower marl layer is characterized by the highest Ru and Rh concentrations, whereas the upper marl layer is characterized by the highest Os and Ir concentrations. The highest Pt and Pd concentrations are found in the lower and upper parts of oil shale seams, respectively.The individual PGEs in the oil shale samples from the Shengli River area exhibit various modes of occurrence. Ru is mainly present in P-bearing minerals and partly associated with the clay and Ca-bearing minerals. Rh is mainly controlled by clay minerals and partly present in the form of apatite. Os occurs mainly in clay minerals and, to a lesser extent, in pyrite and apatite. Pd and Ir are mainly associated with Ca-bearing minerals and apatite. Pt is mainly present in Ca-bearing minerals and partly related to organic matter and apatite.     

油页岩矿物质催化半焦燃烧特性及机理

利用微型流化床反应分析仪（MFBRA）研究了油页岩矿物质催化半焦燃烧特性,重点考察了半焦内部矿物质和外部页岩灰床料对半焦燃烧的催化作用,揭示了流化床反应器中半焦燃烧过程和机理。结果表明：内部矿物质和外部床料对半焦燃烧均具有明显催化作用,而两者共同催化效果最为显著。矿物质中CaO和Fe₂O₃对半焦燃烧具有催化活性,CaO催化作用强于Fe₂O₃。油页岩半焦燃烧反应活化能在60.41~78.97 kJ/mol之间,矿物质的催化作用会明显降低反应活化能。流化床反应器中,矿物质对半焦燃烧的催化作用主要表现在四个反应,即：挥发分裂解和燃烧、半焦表面炭燃烧、半焦内部炭燃烧以及一氧化碳燃烧。     

Characteristics and mechanism of catalytic effect of inner minerals on combustion of oil shale coke

The micro fluidized bed reaction analyzer (MFBRA) was used to study the combustion characteristics of oil shale mineral catalytic semi-coke. This study compared the effect of minerals inside char and bed material (oil shale ash) outside char on char combustion, and the process and mechanism of char combustion in the fluidized bed were further revealed. Both of minerals inside char and bed material outside char had a marked catalysis for char combustion and their combined catalysis was most notable. It is found that the CaO and Fe₂O₃ were the major active components in oil shale minerals for catalytic combustion of char, and the catalysis of CaO was stronger than that of Fe₂O₃. The activation energy of char combustion ranged from 60.41 kJ/mol to 78.97 kJ/mol, and it would significantly decrease with presence of the catalysis by minerals in oil shale. For char combustion in a fluidized bed, the contribution of minerals to catalytic combustion was mainly reflected in four reactions, such as volatiles cracking and combustion, surface carbon combustion, internal carbon combustion and CO combustion.     

Mineral and trace element composition of the Lokpanta oil shales in the Lower Benue Trough, Nigeria

The concentrations of minerals and trace elements in the Lokpanta oil shale from the Lower Benue Trough, Nigeria have been determined by X-ray diffraction (XRD) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), respectively. X-ray diffraction data were evaluated using the SIROQUANT™ interactive data processing system based on Rietveld interpretation methods. A new method of trace element determination in oil shale, involving LA-ICP-MS analysis of glass beads prepared by fusing oil shale ash on an iridium strip heater was used, and the accuracy of the method was assessed by including a standard shale reference material (SGR-1b) in the analysis program.The minerals in the raw oil shales are mainly quartz, calcite and clay minerals, with the latter being represented by kaolinite and interstratified illite/smectite. Ashes of the oil shale samples prepared at 815 °C have quartz and (in some cases) illite as the dominant mineral phases, along with a significant proportion of amorphous materials. The Lokpanta oil shales are highly enriched in some potentially hazardous trace elements, including V, Cr and Ni, when compared with oil shales from other deposits around the world. The results obtained for the trace elements in the reference material show that the LA-ICP-MS method described in this study is very accurate and precise for the determination of a wide range of trace elements in oil shales.     

固有碳酸盐和硅酸盐对太姥油页岩热解产物的影响

通过逐级酸洗脱除新疆太姥油页岩中的碳酸盐和硅酸盐矿物,采用铝甑炉对油页岩原样和脱矿样进行热解,分析油气产物的组成性质,基于产物产率和性质考察了固有矿物质对油页岩热解的影响。结果表明,碳酸盐能促进热解生油,且使页岩油中含氮、氧化合物含量增大,硅酸盐则抑制热解生油,并抑制含氧化合物的生成,二者均使页岩油的H/C降低。硅酸盐可促进烷基自由基与氢自由基的结合,使页岩油中烷烃含量升高、烯烃含量降低,且使H₂产率减小,并能催化长链脂肪烃的裂解,使页岩油中长链烃含量降低、短链烃含量升高,且使烃类气体产率增大,而碳酸盐则抑制自由基的结合和长链脂肪烃的裂解。     

Effect of demineralization of El-lajjun Jordanian oil shale on oil yield

The effect of demineralization on oil yield and mineral composition of Jordanian oil shale was investigated. A standard digestion procedure using a range of inorganic and organic acids including HCl, HNO₃, HF, and CH₃COOH was used to enhance the oil recovery of oil shale samples collected from the El-lajjun area. The total yield of the digested samples, as determined by Fischer Assay, has shown a maximum value (two folds the untreated sample) obtained when using CH₃COOH. The kaolin in the treated oil shale with a high concentration of CH₃COOH is believed to have transformed to illite as found in the XRD analysis. The treatment of oil shale using HCl has shown an increased ratio of oil to gas as a result of the digestion of calcite in the oil shale. At higher concentrations of HNO₃, the acid is believed to react with the kerogen in the oil shale resulting in high levels of low molecular weight compounds. Therefore, the amount of non-condensable gases produced by Fischer assay after treatment with a high concentration of HNO₃ is relatively high. HF is believed to drive off water from the oil shale by dissolving the clay minerals leading to increased oil to gas ratio.     

Characterisation of some Australian oil shale using thermal, X-ray and IR techniques

Thermogravimetric analysis (TGA), Diffuse Reflectance Infrared Fourier Transforms Spectroscopy (DRIFTS) and X-ray diffraction (XRD) were used in conjunction to characterise oil shale samples from an Australian Tertiary oil shale deposit. Results from these techniques were compared with conventional Modified Fisher Assay (MFA) data. DRIFTS and TGA results showed clear correlations with each other as well as with the MFA values. DRIFTS results indicated that most of the kerogen is in aliphatic hydrocarbon form. It was evident from TGA analysis that the weight loss in the 450-550 °C temperature region has a strong and direct correlation with the amount of oil in the samples, as determined by the MFA method. Calibration curves were generated in which oil content can be predicted from TGA and DRIFTS data. The combination of TGA and DRIFTS is mostly useful in examining organic matter in oil shale while DRIFTS and XRD combination is useful in examining the minerals phases. XRD and DRIFTS showed good agreement in identifying the presence of minerals such as quartz, clay and carbonates. Combination of these three techniques can provide an alternative and inexpensive method to the MFA analysis in determining the kerogen content, while overcoming the limitations of each other.     

Secondary coking and cracking of shale oil vapours from pyrolysis or hydropyrolysis of a Kentucky Cleveland oil shale in a two-stage reactor

It is widely recognized that secondary reactions which are mainly associated with minerals during oil shale retorting have a marked influence on the product yields and compositions. To understand these phenomena more clearly, the secondary reactions of shale oil vapours from the pyrolysis (or hydropyrolysis) of Kentucky Cleveland oil shale were examined in a two-stage, fixed-bed reactor in flowing nitrogen or hydrogen at pressures of 0.1–15 MPa. The vapours from pyrolysis (first stage) were passed through a second stage containing combusted shale, upgrading catalyst or neither. Carbon conversion to volatile products in the first stage increased from 49% during thermal pyrolysis to 81% at 15 MPa H₂ partial pressure. During thermal pyrolysis, total pressure had only a slight effect on carbon removal from the raw shale and subsequent deposition on to the porous solids in the second stage. Carbon deposition on to the combusted shale in the second stage was reduced to zero at 15 MPa H₂ partial pressure. The n-alkane distributions of the oils as determined by gas chromatography clearly demonstrated that higher hydrogen pressure, contact with combusted shale, or both contributed to lower-molecular-weight products.     

Effect of acid dissolution on the mineral matrix and organic matter of Zefa EFE oil shale

Kerogen of the Israeli Zefa oil shale was isolated and the changes which occur in the initial organic matter during the removal of the inorganic matrix were investigated. Benzene-methanol extraction dissolved the bitumens, hydrochloric acid and hydrofluoric acid dissolution removed the carbonate and silicate minerals and lithium aluminium hydride treatment destroyed pyrite mineral which was unaffected by the attack of acids. X-ray diffractograms and FTIR spectra of the original oil shale and its demineralized products were measured. Benzene-methanol extraction of the oil shale increased the resolution of peaks in the X-ray diffractograms X-ray diffractograms and FTIR spectra indicated the presence of calcite, α-quartz, kaolinite, illite and pyrite in the mineral matrix of the shale. Hydrochloric and hydrofluoric acid dissolution did not cause hydrolysis and oxidation of the organic matter. Lithium aluminium hydride treatment reduced the carbonyl functionalities to newly formed hydroxyl groups, therefore the kerogen isolated seemed to have a chemical composition different from that of the original oil shale.     

油页岩的成矿机理研究

油页岩的沉积环境有很多种,而且组成各不相同。油页岩可按照组成（例如方解石等碳酸盐矿物质或石英、粘土等碎屑矿物质）或沉积环境（海相,湖相和陆相）进行分类。油页岩中的大多数有机质起源于藻类,少数起源于陆上维管植物的残骸。有机质的三种主要类型是结构藻类体、层状藻类体和沥青质体。某些油页岩也包括金属钒、锌、铜和铀等。大多数油页...     

Method for determining the kinetics of cracking and coking of shale oil vapours in fluidized beds

The secondary cracking and coking of oil vapours produced from oil shale retorting have been previously shown to depend upon the nature and temperature of the substrate over which these reactions occur. To realistically examine the kinetics of these reactions during fluidized bed retorting, an apparatus has been developed which permits shale oil vapours generated in one fluidized bed to pass over selected substrates in a second fluidized bed. Substrates can be fed as a batch or continuously. In the batch mode, the substrate is heated to reaction temperature and is then exposed to shale oil vapours for a chosen period of time. Carbon deposition onto the solid is monitored in real-time by combusting the pyrolysis products and measuring the oxides of combustion with an on-line mass spectrometer. The extent of carbon uptake is also determined by elemental analysis of the substrate following reaction. These two methods of analysis were shown to correspond well under all the conditions investigated. In the continuous mode, substantial amounts of product oil can be collected so the effects of cracking may be evaluated. The rates of carbon deposition onto processed shales and pure minerals have been measured.     

油页岩气体热载体干馏过程模拟

运用Aspen Plus软件,将油页岩定义为常规物流、非常规物流和常规惰性固体物流的混合物流,结合油母质热解机理、总包一级热解动力学模型,建立了油页岩气体热载体干馏炉模型。在干馏炉正常运行温度下,对油页岩中有机质及其热解产物页岩油、热解气体、半焦等物质的质量进行了计算和分析,并对不同温度下有机质及其热解产物的质量进行了计算和分析。模拟结果与干馏炉设计运行参数符合较好,能方便的对不同温度下热解产物的质量进行预测。     

Quantitative study of the carboxylic acids in Green River oil shale bitumen

Bitumen fractions were extracted by a benzene/methanol reflux of Green River oil shale (GROS) before and after treatment with HCl, HF, and HCl/HF. Acid leaching released 80% more bitumen than could be extracted without acid treatment. This additional bitumen had greater concentrations of carboxylic acids and their salts than the untreated oil shale bitumen. The carboxylic acids were separated from all bitumen fractions (untreated, post HCI, post HF, and post HF/HCl) and individual acids were identified and quantified by gas chromatography—mass spectrometry and high resolution mass spectrometry. The same types of acids were present in all four bitumen fractions but showed significant differences in their relative abundances. These carboxylic acids and salts were present in the original GROS and were not formed during the treatment. The post-HCl bitumen fraction contained Mg and Fe salts of long-chain aliphatic carboxylic acids with carbon numbers in the range of 21–38. Significantly, even though calcium is the major cation in the carbonate minerals of GROS, no Ca was present in the ash of these carboxylic acid salts. These results indicate that there is a strong interaction between carboxylic acids present in GROS and its mineral matrix (especially carbonate minerals). These carboxylic acids are possible coupling agents that ‘glue’ mineral and organic material together. The treatment of the oil shale also resulted in the formation of highly purified kerogen, low in ash yield (2 wt %) which had undergone only very mild acid treatment.     

Treatment of Green River oil shale by carbon dioxide and water: evidence for association of bitumen and carbonate materials

The use of CO₂ under pressure to disaggregate the mineral matrix of Green River oil shale has been studied. The degree of disaggregation was measured by changes in particle size distribution and the amount and constituency of the bitumen released after treatment. Although the effectiveness of this technique was minimal, it did afford greater insight into the physical and chemical characteristics of Green River oil shale, and provided further evidence for the strong association of bitumen, kerogen, and minerals through carboxylic acids, acting as coupling agents.     

Removal of hydrogen sulphide by combusted Rundle oil shale: sulphidation of iron oxides

Oil shale from the Rundle deposit of Queensland, Australia, after retorting and combustion in air, contains haematite and magnetite. Studies of the reactions of hydrogen sulphide with this combusted shale, and with the individual iron oxides, showed the sulphidation kinetics to be first order with respect to hydrogen sulphide, with activation energies of 35 ± 1, 59 ± 3 and 66 ± 2 kJ mol⁻¹ respectively for haematite, magnetite and combusted shale. Under dry conditions the shale trapped 36 mg of hydrogen sulphide per gram of combusted shale. With steam present, the iron oxides did not trap hydrogen sulphide and the combusted shale was also ineffective because, apart from negligible sulphidation of its iron oxide minerals, another sulphur-trapping mineral, calcium oxide, had effectively been removed by silication during combustion. The potential to control hydrogen sulphide (produced during steam retorting of shale) by recycled combusted Rundle shale is therefore poor, but a characteristic of this shale during pyrolysis is that most hydrogen sulphide is released above 500 °C, so that by minimizing retort temperatures, consistent with appropriate oil recovery, substantial control of hydrogen sulphide should be possible.     

油页岩中矿物质对挥发分不凝气释放过程的影响

对桦甸油页岩（OS-R）采用HCl/HF/HNO3处理,分别得到去碳酸盐样品（OS-C）、去碳酸盐及硅酸盐样品（OS-F）以及有机质样品（OS-N）,用XRD鉴别其矿物组成,然后通过TG-FTIR-MS研究有机质脱挥发分机理及不同矿物质对挥发分不凝气释放过程的影响。结果表明：黄铁矿的存在使挥发分不凝气体释放的初始温度明显降低,反应更易进行,且使生成的不凝气产量更高,尤其是对不凝气中H2O生成促进作用更显著;硅铝酸盐的存在使不凝气体产量明显减少,提高了不凝气释放的初始温度,减少了不凝气释放的过程时间。然而碳酸盐的存在能增加不凝气产量,使CO2脱出的初始温度更低。     

Pyrolysis kinetics for Green River oil shale from the saline zone

The nature of the organic and mineral reactions during the pyrolysis of Saline-zone Colorado oil shale containing large amounts of nahcolite and dawsonite has been determined. Results reported include a material-balanced Fischer assay and measurements of gas evolution rate of CH₄, C₂H_x, H₂, CO and CO₂, Stoichiometry and kinetics of the organic pyrolysis reactions are similar to oil shale from the Mahogany zone. X-ray diffraction and thermogravimetric analysis results are used to help determine the characteristics of the mineral reactions. Kinetic expressions are reported for dawsonite decomposition, and it is demonstrated that the temperature of dolomite decomposition is substantially lower than for Mahogany-zone shale because of the presence of the sodium minerals.     

Iron partitioning in oil shale of the Green River Formation,Colorado: A preliminary Mössbauer study

Oil shale of the Green River Formation (Eocene) in the Piceance Creek Basin, Colorado contains seven major iron-bearing minerals: pyrite, marcasite, pyrrhotite, Mg-siderite, Fe-dolomite, ankerite and Ca-ankerite. Only recently have workers recognized that these rocks contain large quantities of iron-bearing carbonate minerals. Preliminary Mössbauer spectroscopy analysis of four oil-shale and two marlstone samples from the Green River Formation shows that the dominant iron-bearing compound is usually an iron-carbonate mineral, generally Ca-ankerite or Fe-dolomite. The second most abundant iron-bearing phase is an iron sulphide, generally pyrite. In the samples studied, the iron partitioning is variable between the carbonate and sulphide phases. Lower grades of oil shale and marlstone also have an iron-bearing silicate phase, which is perhaps an iron-bearing phyllosilicate, possibly chlorite.     

窑街油页岩粉末成型的工业干馏试验分析

采用河南理工大学研制的HPU-B黏结剂,将窑街油页岩粉末在甘肃窑街油页岩综合利用公司现场加工成型200 t页岩球,并于神木三江SJ型干馏方炉中完全取代块岩进行工业试验。结果显示：干馏炉运行完全正常,半焦能从熄焦池中顺利刮出,除页岩球半焦中残油率偏高外,油页岩粉末成型制备的页岩球完全可满足干馏工艺要求,通过对成型工艺和干馏炉参数进一步优化和调整后,页岩球完全可以替代块岩进行干馏。     

小颗粒油页岩热裂解制取页岩油试验研究

针对中国小颗粒油页岩的利用现状,在实验室条件下,利用自行研制的流化床热裂解装置进行了小颗粒油页岩制取页岩油的试验研究,通过正交试验优化出了热裂解制取页岩油的最优工艺参数。实验结果表明,在最优工艺条件下,产油率在5%左右。因此流化床热裂解技术是一种有效的小颗粒油页岩加工制油的新方法。