Trace elements in Nigerian oil sands and extracted bitumens

The Nigerian oil sands are very extensive with an estimated in place reserves of bitumen/heavy oil of over 30 billion barrels. Instrumental Neutron Activation Analysis (INAA) has been used to determine the trace and minor elements in the raw oil sands and bitumens. About 43 trace elements in the raw oil sands and 30 in bitumen extracts were determined. The results are compared with values of Canadian bitumens and some Nigerian conventional light crude oils. In general, the Nigerian bitumens has higher hydrocarbon concentration than the Athabasca bitumen but slightly lower than in the Nigerian crude oils. The sulphur, vanadium and nickel contents of the Nigerian bitumens and crude oils are appreciably lower than those of Athabasca bitumen, thus indicating that the extraction and refining of Nigerian tar sand oil would pose less technological and environmental problems than the Athabasca syncrude.     

Microwve induced catalytic reactions of carbon dioxide and water: mimicry of photosynthesis

In an attempt to emulate the highly successful photosynthetic recycling of CO₂ to form energetically useful fuels in nature this study investigates the microwave induced reaction of carbon dioxide and water in a continuous flow system using a supported nickel catalyst and 2.45 GHz microwave radiation with an average incident power of 2.2 kW. The major reaction products were methane, ethane, methanol, acetone, C₃ and C₄ alcohols. The yields of methane, C₃ and C₄ alcohols reached maximum values after 30 s of irradiation, while the yields of ethane, methanol and acetone were proportional to the irradiation time within the investigated range.     

Thermogravimetric characterization of some iraqi bitumens

The thermogravimetric analysis of various Iraqi bitumens was conducted by heating them in a stream of nitrogen or oxygen gas from room temperature to 800°C at a rate of 20°C mm^?1 while recording the partial weight loss at 100°C intervals in addition to the total weight loss Isothermal measurements in nitrogen gas were also performed by heating the bitumens from room temperature to 165°C and holding isothermally at this level for 250 min. The resulting thermogravimetric curves provided well-defined data for the characterization and identification of the bitumens studied.     

Thermal analysis of coals,oil shales and oil sands

Instances where differential scanning calorimetry and thermogravimetry have been applied to the study of coals, oil shales and oil sands are reviewed. Work carried out in this laboratory and model studies culled from the literature are used as examples to illustrate a particular application. The topics covered include characterization, assay, thermal stability determination and simulation of processing conditions.     

Geochemical characterisation of heavily biodegraded tar sand bitumens by catalytic hydropyrolysis

Catalytic hydropyrolysis was used to release the aliphatic biomarkers covalently bound within the asphaltene structure of highly biodegraded Nigerian tar sand bitumens. Unlike the free aliphatic hydrocarbons extracted from the bitumen, the hydropyrolysis products of the asphaltenes afford aliphatic biomarkers having the characteristics of the initial unaltered oil, which had been trapped within the asphaltene matrix of the bitumen and protected from biodegradation processes. The biomarker profiles obtained allow proper characterisation of the bitumen in terms of source and thermal maturity. Catalytic hydropyrolysis is also capable of releasing aromatic hydrocarbons that can be used in the geochemical characterisation of the bitumen.     

Formaldehyde-volatilization method for the decomposition of sands, quartzites etc

Summary For the decomposition of sands, quartzite etc. a method is recommended, in which the sample is treated with nitric and hydrofluoric acids and evaporated to dryness. The nitrates so formed are decomposed with formaldehyde at 750° C. In the first stage nitrites are formed, which are subsequently decomposed to oxides. Silica is determined from the weight difference. The oxides are brought into solution with hydrofluoric and perchloric acids and from this solution other major, minor and trace constituents may be determined.

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Zusammenfassung Zum Aufschluß von Sand, Quarzit und ähnlichen Material wird empfohlen, die Probe mit Salpeter- und Flußsäure zu behandeln und nach dem Eindampfen die gebildeten Nitrate mit Formaldehyd bei 750° C zu zersetzen. Hierbei werden zunächst Nitrite, anschließend Oxide gebildet. Der Silicatgehalt wird aus der Gewichtsdifferenz bestimmt. Die Oxide werden mit Fluß- und Perchlorsäure gelöst, und aus dieser Lösung können andere Bestandteile bestimmt werden.

     

扎赉特旗油砂在氮气气氛下的热解制油研究

油砂是一种含有沥青或其他重质石油的沉积岩,主要用于提取油砂沥青,以生产合成原油。中国拥有相当数量的油砂资源,目前还未开采,仅处于初步研究阶段。加拿大在20世纪初期就展开了油砂的开采及制油研究工作,并于20世纪70年代由加拿大合成油公司实现了工业化生产。油砂生产的沥青和合成油已占其石油总产量的1／4以上。     

Pulsed microwave catalytic decomposition of olefins

The application of the recently developed, versatile and economic technique of microwave assisted catalysis to the reactions of olefinic hydrocarbons, principally ethylene, propylene and 1-pentene is discussed. The reactions are believed to involve free radical intermediates and can result in efficient conversions to selected aliphatic and aromatic hydrocarbons.     

Interaction forces in bitumen extraction from oil sands

Water-based extraction process (WBEP) has been successfully applied to bitumen recovery from Athabasca oil sand ore deposits in Alberta. In this process, two essential steps are involved. The bitumen first needs to be "liberated" from sand grains, followed by "aeration" with air bubbles. Bitumen "liberation" from the sand grains is controlled by the interaction between the bitumen and sand grains. Bitumen "aeration" is dependent, among other mechanical and hydrodynamic variables, on the hydrophobicity of the bitumen surface, which is controlled by water chemistry and interactions between bitumen and fine solids. In this paper, the interaction force measured with an atomic force microscope (AFM) between bitumen-bitumen, bitumen-silica, bitumen-clays and bitumen-fines is summarized. The measured interaction force barrier coupled with the contacted adhesion force allows us to predict the coagulative state of colloidal systems. Zeta potential distribution measurements, in terms of heterocoagulation, confirmed the prediction of the measured force profiles using AFM. The results show that solution pH and calcium addition can significantly affect the colloidal interactions of various components in oil sand extraction systems. The strong attachment of fines from a poor processing ore on bitumen is responsible for the corresponding low bitumen flotation recovery. The identification of the dominant non-contact forces by fitting with the classical DLVO or extended DLVO theory provides guidance for controlling the interaction behavior of the oil sand components through monitoring the factors that could affect the non-contact forces. The findings provide insights into megascale industrial operations of oil sand extraction.     

Recent progress in catalytic NO decomposition

Recent progress in catalytic direct NO decomposition is overviewed, focusing on metal oxide-based catalysts. Since the discovery of the Cu-ZSM-5 catalyst in the early 1990s, various kinds of catalytic materials such as perovskites, C-type cubic rare earth oxides, and alkaline earth based oxides have been reported to effectively catalyze direct NO decomposition. Although the activities of conventional catalysts are poor in the presence of coexisting O₂ and CO₂, some of the catalysts reviewed in this article possess significant tolerance toward these coexisting gases. The active sites for direct NO decomposition are different depending on the types of metal oxide-based catalysts. In the case of perovskite type oxides, oxide anion vacancies act as catalytically active sites on which NO molecules are adsorbed. C-type cubic rare earth oxides contain oxide anion vacancies with large cavity space, enabling easy access of NO molecules and their subsequent adsorption. Surface basic sites on alkaline earth based oxides participate in NO decomposition as active sites on which NO molecules are adsorbed as NO₂⁻ species. The reaction mechanisms of direct NO decomposition are also discussed.     

Thermooxidative decomposition of oil shales

The thermooxidative decomposition of four oil shale samples from Estonia, Jordan, Israel and Morocco and one sample of Estonian oil shale derivative, semicoke, was studied with the aim to determine the characteristics of the process and the differences of it related to the origin of oil shale. The experiments with a Setaram Setsys 1750 thermoanalyzer coupled to a Nicolet 380 FTIR Spectrometer were carried out under non-isothermal conditions up to 1000 °C at the heating rates of 1, 2, 5, 10 and 20 °C min⁻¹ in an oxidizing atmosphere. A model-free kinetic analysis approach based on the differential isoconversional method of Friedman was used to calculate the kinetic parameters. The results of TG–DTA–FTIR analyses and the variation of activation energy E along the reaction progress α indicated the complex character of thermooxidative decomposition of oil shale and semicoke, being at that the most complicated for Estonian and Jordanian oil shale characterized by higher content of organic matter as compared to the other samples studied.     

Thermal decomposition of some hexaborates

Thermal decomposition of iron(II) and cobalt(II) hexaborates has been investigated. The methods applied to investigate the process were differential thermal analysis, derivatography, crystallooptics and x-ray study. The following iron(II) hexaborate hydrates, FeO · 3B₂O₃ · 7.5H₂O, FeO · 3B₂O₃ · 5H₂O, FeO · 3B₂O₃ · 0.5H₂O; iron(III) borates, Fe₂O₃ · 6B₂O₃ and 2Fe₂O₃ · B₂O₃; cobalt(II)hexaborate hydrates CoO · 3B₂O₃ · 7.5H₂O, CoO · 3B₂O₃ · 5H₂O, CoO · 3B₂O₃ · 0.5H₂O, CoO · 3B₂O₃ and the decomposition product 2CoO · 3B₂O₃ have been isolated. Hepta- and semihydrates of cobalt(II) and iron(II) hexaborates have been proved to be isomorphous. It has been established that in the case of cobalt and iron hexaborates the exothermic maximum refers to a decomposition reaction and to the formation of a borate containing a smaller proportion of boron and boric anhydride.     

Kinetics of the catalytic decomposition of dichloromethane and trichloromethane

The kinetics of the catalytic decomposition of dichloromethane and trichloromethane in a single row plug flow reactor at 400–500°C has been studied. Dichloromethane decomposes into carbon and hydrogen chloride (presumably via the intermediate formation of monochlorocarbene). Trichloromethane decomposes mainly into carbon, hydrogen chloride and tetrachloromethane (presumably via the intermediate formation of dichlorocarbene).     

Pyrolysis and combustion model of oil sands from non-isothermal thermogravimetric analysis data

Thermogravimetric (TG) data of oil sand obtained at Engineering Research Center of Oil Shale Comprehensive Utilization were studied to evaluate the kinetic parameters for Indonesian oil sand samples. Experiments were carried out at heating rates of 5, 15, and 25 °C min^?1 in nitrogen, 10, 20, and 50 °C min^?1 in oxygen atmosphere, respectively. The extent of char combustion was found out by relating TG data for pyrolysis and combustion with the ultimate analysis. Due to distinct behavior of oil shale during pyrolysis, TG curves were divided into three separate events: moisture release, devolatilization, and evolution of fixed carbon/char, where for each event, kinetic parameters, based on Arrhenius theory, were calculated. Coats–Redfern method, Flynn–Wall–Ozawa method, and distributed activation energy model method have been used to determine the activation energies of degradation. The methods are compared with regard to their characteristics and the ease of interpretation of the thermal kinetics. Activation energies of the samples were determined by three different methods and the results are discussed.     

The modes of decomposition of some rare-earth-metal tropolonates and activation energies of decomposition

The modes of decomposition of some rare-earth-metal tropolonates were studied by the use of DT, TG and DTG techniques. The volatile products and residueswere identified. The activation energies of decompositions were calculated.The rare-earth-metal tropolonates decompose in two steps: the first yielding a basic tropolonate and the second a basic carbonate for Sm and Eu tropolonates and the normal trioxides for La, Nd, Er, Tm and Yb tropolonates. The activation energies of decomposition of these tropolonates vary from 21.0 to 96.5 kcals/mole and is environment-sensitive.

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Zusammenfassung Die Zersetzungsarten der Tropolonate einiger Seltener Erden wurden an Hand von DTA-, TG- und DTG-Techniken untersucht und die flüchtigen Produkte und Rückstände identifiziert. Die Aktivierungsenergien der Zersetzungsvorgänge wurden errechnet.Die Tropolonate der Seltenen Erden werden in zwei Stufen zersetzt: die erste ergibt ein basisches Tropolonat und die zweite ein basisches Carbonat für Sm- und Eu-Tropolonate und die normalen Trioxide für La, Nd, Sr, Ta und Yb-Tropolonate. Die Aktivierungsenergien der Zersetzungsreaktion dieser Tropolonate variieren zwischen 21.0 und 96.5 kcal/mol und sind umgebungsempfindlich.

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Résumé On a étudié par ATD, TG et TGD le mécanisme de la décomposition des tropolonates de quelques terres rares. On a identifié les produits volatils, ainsi que les résidus. On a calculé les énergies d'activation.Les tropolonates de terres rares se décomposent en deux étapes: la première fournit un tropolonate basique et la seconde un carbonate basique dans le cas des tropolonates de Sm et d'Eu et les sesquioxydes correspondants pour La, Nd, Er, Tm et Yb. Les énergies d'activation de la décomposition de ces tropolonates varient de 21.0 à 96.5 kcal/mol et dépendent du milieu environnant.

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, . . . : , Sm Eu, , La, Nd, Er, Tm Yb . 21,0–96,5 /.

     

Thermal decomposition of some metal sulphates

The thermal decomposition temperatures of some metal sulphates (iron, copper, cobalt, nickel, zinc and lead sulphates) have been investigated by TG and DTA. The mechanism of decomposition of these sulphates is discussed, making use of additional information obtained from isothermal studies and X-ray diffraction measurements. The activation energies of these reactions were calculated and found to increase, with almost the same increments, in the order Zn<Fe<Co<Ni<Cu.     

Thermal decomposition of some diuretic agents

Thermogravimetry-derivativc thermogravimetry and differential scanning calorimetry were used to study the thermal behaviour of furosemide, hydrochlorothiazide, spironolactone, and amiloride hydrochloride. The results revealed the extents of their thermal stability and also permitted interpretations concerning their thermal decompositions.The authors thank FAPESP (Proc. 90/2932-4) and CNPq for financial support, and Hoechst of Brazil, Prodome Química e Farmaceutica Ltda, Campinas, Brazil, and Biolab. Industrias Farmaceuticas, Brazil, for supplying the diuretic agents used in this study.     

Thermal decomposition of some analgesic agents

Thermogravimetry, derivative thermogravimetry (TG, DTG) and differential scanning calorimetry (DSC), were used to study the thermal behaviour of mefenamic acid, ibuprofen, acetaminophen, sodium diclofenac, phenylbutazone, dipyrone and salicylamide. The results led to thermal stability data and also to the interpretation concerning the thermal decomposition.The authors thank the FAPESP (Proc. 90/2933-4) and Biogalenica Quimica e Farmaceutica Ltda, Merrel Lepetit Farmaceutica Ltda, Roche Quimicos e Farmaceuticos S.A., Rhodia S.A. and Aché Laboratorios Farmaceuticos S.A., for supplying the analgesic agents.     

Thermal decomposition of some metal-organic precursors

In this paper we present a study on the synthesis of Fe(III) oxide, by thermal decomposition of some complex combinations of Fe(III) with carboxylate type ligands, obtained in the redox reaction between some polyols (ethylene glycol (EG), 1,2-propane diol (1,2PG), 1,3-propane diol (1,3PG) and glycerol (GL)) and NO₃ ^– ions (from ferric nitrate). Fe₂O₃ was obtained by thermal decomposition of the synthesized metal-organic precursors at low temperatures. γ-Fe₂O₃ was obtained as nanoparticles at 300°C, while at higher temperatures α-Fe₂O₃ starts to crystallize and becomes single phase at ~500°C. The formation of the metal-organic precursors and their thermal decomposition were studied by thermal analysis and FTIR spectroscopy.