Kinetic study of heavy crude oils by thermal analysis

The present work investigates the thermal behavior and kinetic of four types of petroleum samples: a medium crude oil—P1, one heavy oil—P2, and two extra heavy oils—P3 and P4 by TG, DTG, and DSC methods. Thus, this study may contribute to the characterization of petroleum with different °API values.     

A study of a New Zealand oil shale by differential thermal analysis

The heats of combustion of 95 samples of oil shale from the Nevis Valley have been determined from DTA peak areas obtained by combustion in 1.5 atm oxygen. The heats of combustion of the oil shale ranged from 0.2 to 8.5 MJ kg⁻¹, with an average of 2.6 MJ kg⁻¹, while that of the kerogen was calculated to be 34.2 MJ kg⁻¹. Up to four peaks were obtained in the DTA combustion curve, suggesting that different parts of the kerogen molecule were being oxidised at different temperatures.

In nitrogen, DTA endotherms were observed due to decarbonation of siderite (ca. 455°C), and dehydroxylation of kaolinite (ca. 570°C) and chlorite (ca. 760°C), and an exotherm due to formation of mullite (ca. 980°C).     

The determination of trace elements in crude oil and its heavy fractions by atomic spectrometry

A literature review on the determination of trace elements in crude oil and heavy molecular mass fractions (saturates, aromatics, resins and asphaltenes) by ICP-MS, ICP OES and AAS is presented. Metal occurrences, forms and distributions are examined as well as their implications in terms of reservoir geochemistry, oil refining and environment. The particular analytical challenges for the determination of metals in these complex matrices by spectrochemical techniques are discussed. Sample preparation based on ashing, microwave-assisted digestion and combustion decomposition procedures is noted as robust and long used. However, the introduction of non-aqueous solvents and micro-emulsions into inductively coupled plasmas is cited as a new trend for achieving rapid and accurate analysis. Separation procedures for operationally defined fractions in crude oil are more systematically applied for the observation of metal distributions and their implications. Chemical speciation is of growing interest, achieved by the coupling of high efficiency separation techniques (e.g., HPLC and GC) to ICP-MS instrumentation, which allows the simultaneous determination of multiple organometallic species of geochemical and environmental importance.     

A study of the mixture of coal and residue of the vacuum distillation of crude oil by thermal analysis

Thermal analysis was used for investigating the effect of the addition of the residue obtained from crude oil vacuum distillation on the carbonization process of brown coal. The kinetic analysis of the experimental TG curves was carried out by using the Coats-Redfern equation and then to select the most likely mechanism (functiong (α)) for particular decomposition stages of brown coal and its mixture with the residue. In the brown coal carbonization process the nucleation of a new solid phase is predominant. In the temperature range of the decomposition of coal (620–820 K) the addition of residue results a change in the mechanism of the thermal decomposition process — in the mixture three-dimensional diffusion processes and one-dimensional diffusion occur, depending on the composition. Above 730 K (secondary carbonation processes) the most likely mechanism involves the nucleation of a new solid phase as well as diffusion processes.     

A thermogravimetric method for distinguishing Alaskan crude oil from that of other world sources

A method for “fingerprinting” crude petroleum to determine the country of origin by thermogravimetry has been developed. Twenty-nine crude oil samples from various sources, both foreign and domestic, have been examined. Comparison of the thermogravimetric data, both graphically and numerically, yield a set of parameters which are useful in distinguishing between crude oil from the Alaskan Prudhoe Bay field and that of fields in other regions of the world.     

A differential thermal analysis (dta) and thermogravimetric analysis (tga) study of some organic acids. part II

The differential thermal analysis and thermogravimetric analysis curves of l6 organic acids are presented. The “procedural weight-loss temperatures” for the anhydrous acids ranged from 115° for salicylhydroxamic acid to 250° for 5-aminosalicylic acid. The DTA curves were characterized by endothermic and exothermic peaks which were caused by fusion, vaporization, sublimation, and decomposition reactions.     

重度原油注空气低温氧化过程研究(英文)

低温氧化反应对现场燃烧(ISC)技术点火的成功有十分重要的影响.采用高压氧化管,研究了不同温度压力下,新疆克拉玛依重度原油的低温氧化过程.结果表明,温度和压力的变化对低温氧化反应的放热程度、持续时间以及气体产物有明显影响.适合油样低温氧化反应的温度和压力分别为150℃和10MPa.此外,采用纯组分替代原油族组分进行低温氧化实验,研究低温氧化反应对原油族组分(饱和烃、芳香烃、胶质、沥青质)含量的影响.结果表明,原油所含族组分中,芳香烃组分最易被氧化,其含量由氧化前的19.17%减少到12.38%(150℃)和9.51%(250℃).随着低温氧化过程的进行,结构复杂的族组分(胶质、沥青质)的含量明显增加.实验数据对油藏实施注空气技术,以及该技术现场实施条件的确定有十分重要的指导意义.     

Studies on use of differential thermal and thermogravimetric techniques for checking compositions of some drug formulations

The suitability of the differential thermal and thermogravimetric techniques for the determination of compositions of solid and soft drug formulations has been studied. A total of 117 pharmaceutical preparations have been examined, including powders, dusting powders, capsules, granulates, tablets, tablets for sucking, effervescent tablets, dragees, suppositories and ointments. Both techniques have been shown to be applicable for identification of pharmaceutical preparations. A specification has been made of thermal processes which can be employed for assaying the main components of the preparations. A rough estimate of the relative errors has been given.

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Zusammenfassung Die Eignung der differentialthermoanalytischen und thermogravimetrischen Methoden zur Bestimmung der Zusammensetzung fester und weicher ArzeneiprÄparate wurde studiert. Eine Gesamtzahl von 117 pharmazeutischen PrÄparaten, einschliesslich Pulver, Streupulver, Kapseln, Granulate, Tabletten, Saugtabletten, Brausetabletten, Dragees, Suppositorien und Salben wurde untersucht. Beide Methoden erwiesen sich als anwendbar zur Identifizierung pharmazeutischer PrÄparate. Eine Spezifizierung der zur Bestimmung der Hauptkomponenten der PrÄparate geeigneten thermischen Prozesse wurde durchgeführt. Eine grobe SchÄtzung der relativen Fehler wurde gegeben.

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Résumé On a étudié l'utilité des techniques ATD et TG pour déterminer la composition des préparations pharmaceutiques solides et molles. On a soumis à l'examen un total de 117 préparations pharmaceutiques comprenant des poudres, des talcs, des capsules, des granulats, des tablettes, des tablettes à sucer, des tablettes effervescentes, des dragées, des suppositoires et des onguents. Les deux techniques se sont montrées applicables à l'identification des préparations pharmaceutiques. On a effectué une spécification des processus thermiques qui se prÊtent au dosage des composants essentiels des préparations. On a donné une évaluation approximative des erreurs relatives.

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A differential thermal analysis study of homoionised bentonites

Homoionised bentonites were prepared from commercial bentonites with hydrochloric acid. The Atterberg limits and the DTA curves were determined for the homoionised and commercial bentonites. This study shows that DTA can be used as a method for differentiation between clays containing mono- and divalent cations.The authors thank Prof. K. S. Sankaran, Department of Civil Engineering, I. I. T., Madras, for his encouragement during the course of this work.     

Combustion characteristics of lignite and oil shale samples by thermal analysis techniques

In this research thermal analysis and kinetics of ten lignite's and two oil shale samples of different origin were performed using a TA 2960 thermal analysis system with thermogravimetry (TG/DTG) and differential al analysis (DTA) modules. Experiments were performed with a sample size of ~10 mg, heating rate of 10°C min^-1. Flow rate was kept constant (10 L h^-1) in the temperature range of 20-900°C. Mainly three different reaction regions were observed in most of the samples studied. The first region was due to the evaporation of moisture in the sample. The second region was due to the release of volatile matter and burning of carbon and called as primary reaction region. Third region was due to the decomposition of mineral matter in samples studied. In kinetic calculations, oxidation of lignite and oil shale is described by first-order kinetics. Depending on the characteristics of the samples, the activation energy values are varied and the results are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

A new quick method of determining the group hydrocarbon composition of crude oils and oil heavy residues based on their oxidative distillation (cracking) as monitored by differential scanning calorimetry and thermogravimetry

A calorimetric-thermogravimetric method is described of determining mass percent contents of distillate fractions, paraffins, base oils, resins, asphaltenes and carbines in various crude oils. The method is based on recording DSC curves of a 10–15 mg sample heated in air in a calorimetric-cell at a rate of 40–50 °C/min. Additionally, weight loss of sample is found at temperatures before and after the reaction. At temperatures from 220 °C or higher distillation of the hydrocarbon mixture starts to be accompanied by its exothermic oxidation, thereby making possible monitoring the distillation (oxidation) of consecutive HC fractions by simple calorimetric-techniques. Differential scanning calorimeter “Thermodat” of high-calorimetric-resolution and sensitivity equipped with dedicated software was used for conducting the experiments and performing all the calculations. Percent contents of the main constituents in a number of heavy and light crude oils were determined and formulas for establishing paraffinic, base oil and coke-forming potentials of crude oils and oil residues derived. One full analysis of a sample takes no longer than 1.0–1.5 h. The method can be used for on-line quality control of various petroleum products, such as atmospheric and vacuum oil residues, cracking residues, lubricants, ceresins and paraffins.     

The study of hydrothermal processes by the differential thermal analysis method

A DTA apparatus has been developed which can operate up to pressures of 500 atm and temperatures of 500°C. A coated thermocouple (thermocoax) is used for the measurement of temperature differences. Thermograms for the dehydration of gypsum, hydration of cement paste and hydrothermal synthesis of calcium silicates hydrates are shown to demonstrate the capability of the apparatus.     

Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis

Journal of Thermal Analysis and Calorimetry - Although micrites (abiotic limestone) and thrombolites (typical biotic limestone), according to the sedimentation and biological action, can be...     

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.     

Analytical study of various heavy oil residues using a transalkylation reaction

Summary Various atmospheric residues of crude oil [Boscan (Venezuela), Maya (Mexico), Kirkouk (Iraq), Safanyia (Saudi Arabia), Arabian Light (Algeria)] have been analyzed by GC/MS coupling after transalkylation. The transalkylation of atmospheric residues from the aromatic matrix to a light aromatic acceptor was performed after optimization of the reaction, using an acidic catalyst/light aromatic acceptor couple: AlBr₃ slightly hydrated/benzene. The reaction time was about four hours and the temperature 60°C. These conditions allow the best compromise between a maximal transfer of alkyl chains and their minimal degradation, which is necessary in an analytical study.The results presented here demonstrate that heavy oil residues from different sources give qualitatively similar GC chromatograms, and that only the amounts of phenylalkanes obtained after transalkylation may vary. Under these conditions, the transfer yields of alkyl chains (defined as the mass of alkylated light aromatics obtained from 100g of oil fraction treated) are significantly different and are thus proposed as a new characteristic of heavy crude oil fractions and of petroleum residues.A thorough quantiative study of the phenyl alkanes identified indicates that in every residue, the amount of compounds containing ramified alkyl chains is constant, whereas linear alkyl chain amounts were observed to vary. Yields of diphenylalkanes are quite different for each residue. This result suggests that the reticulation of the aromatic matrix is a function of the nature of the oil residue.     

A multidimensional gas chromatography method for the analysis of hydrogen sulfide in crude oil and crude oil headspace

Two‐dimensional heart‐cutting gas chromatography is used to analyze dissolved hydrogen sulfide in crude samples. Liquid samples are separated first on an HP‐PONA column, and the light sulfur gases are heart‐cut to a GasPro column, where hydrogen sulfide is separated from other light sulfur gases and detected with a sulfur chemiluminescence detector. Heart‐cutting is accomplished with the use of a Deans switch. Backflushing the columns after hydrogen sulfide detection eliminates any problems caused by high‐boiling hydrocarbons in the samples. Dissolved hydrogen sulfide is quantified in 14 crude oil samples, and the results are shown in this work. The method is also applicable to the analysis of headspace hydrogen sulfide over crude oil samples. Gas hydrogen sulfide measurements are compared to liquid hydrogen sulfide measurements for the same sample set. The chromatographic system design is discussed, and chromatograms of representative gas and liquid measurements are shown.