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.     

Nuclear-physical methods of analysis in oil geology and industry of Kazakstan

Methods and results of elemental analysis of hydrocarbons performed by nuclear-physical methods are presented. It is shown that activation analysis (AA), X-ray fluorescent (XRF) analysis and atomic-emission spectroscopy with inductively-coupled plasma (AES-ISP) allow determination of up to 30 elements in oils and bitumens and up to 40 elements in petroleum cokes, in oil-bitumen rocks, in oil and coal shales. Presented are the results of scientific and practical applications of the developed techniques.     

Modified Paving Bitumens Based on Tar and Petroleum Polymeric Resins

Modification of tar with petroleum polymeric resins yields paving-grade bitumens with enhanced cohesion. With respect to the heat resistance and other parameters, these bitumens meet the requirements of GOST (State Standard) for BND 90/130 paving bitumens.     

Thermal and structural characterization of bitumen by modulated differential scanning calorimetry

Journal of Thermal Analysis and Calorimetry - This paper presents the results of investigation of model bitumens, prepared by mixing of individual fractions of bitumen (saturates, aromatics, waxes,...     

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.     

Melting and glass transitions in paraffinic and naphthenic oils

Naphthenic and paraffinic oils were analyzed by modulated differential scanning calorimetry (MDSC). The results showed several improvements in the analysis of thermal properties when compared with standard DSC. The glass transition temperature (T_g), the enthalpy relaxation at T_g, and the melting endotherms could be deconvoluted, and reversible melting could be identified. This allowed for an easier interpretation of the thermal properties of the oils. With MDSC, the T_gs in mineral oils were found to coincide with endothermic enthalpy relaxation, which is generally regarded as a melting endotherm with standard DSC. A decrease in heat capacity after T_g was attributed to the existence of rigid amorphous material. From Δc_p at T_g and the oil molecular weight, the number of repeat units in the oil chains was estimated at less than 20. The T_g of a hypothetical pure aromatic oil was found to be similar to that for petroleum asphaltenes, and that for a naphthenic oil of infinite molecular weight to be similar to that of petroleum resins.     

Differential scanning calorimetry characterization of water-in-oil emulsions from Mexican crude oils

A simplified equation relating water droplet size distribution to crystallization temperature, determined from differential scanning calorimetry (DSC) curves of aqueous emulsions of petroleum is reported in this article. A series of water-in-oil (W/O) emulsions was prepared by dispersion of water in different Mexican crude oils; in a classical DSC experiment, these emulsions were submitted to a regular heating and cooling cycle within temperatures including freezing and heating of dispersed water. The Z-average diameters of the water drops (D _dz) were estimated this way and correlated with petroleum composition.     

Characterization of hydrocarbon waxes and polyethylenes by DSC

Thermal analysis, originally the technique of DTA, and more recently that of DSC, has been proposed as a means of characterizing waxes. Alternative methods of analysis (refractive index, infrared spectroscopy, etc.) give only a limited amount of information when applied to hydrocarbon waxes. DSC, on the other hand, not only offers a means of distinguishing between microcrystalline, paraffinic, Fischer—Tropsch synthetic, and polyethylene waxes, but offers a scheme by which various hydrocarbon waxes may be fingerprinted. Good agreement between DSC data and the TAPPI system, which utilizes melting point and refractometry, is demonstrated.     

Effect of the Solvent Composition on the Content of the Crystalline Phase and Melting Temperature of Paraffin Waxes

Russian Journal of Applied Chemistry - The results of a study of melting the commercial waxes in the composition of asphaltene-resin-paraffin deposits and for comparison of petroleum waxes in...     

Prediction of the Quality of Petroleum Tars and Bitumens by Infrared Spectroscopic and X-ray Diffraction Methods

The degree of aromaticity of petroleum tars, bitumens, and their fractions is characterized by infrared spectroscopy and X-ray diffraction.     

高熔点蜡合成技术的研究进展

高熔点蜡(熔点 > 80 ℃)具有高熔点、高稳定性、低针入度、低迁移率以及耐磨坚硬等特点,在食品化妆、材料加工、电子机械、国防航空以及医疗领域有着重要的应用。但目前市场上的蜡产品熔点(50–70 ℃)较低。而我国高熔点蜡和特种蜡的需求量日益增加,预计缺口将突破70万吨。本文详细综述国内外合成高熔点蜡(熔点 > 80 ℃)的技术和工艺,包括聚乙烯蜡、费托蜡和生物质基蜡等,尤其对工艺涉及的催化剂和反应机理等进行了分析。聚乙烯裂解制备具有成本低、可以有效解决“白色污染”等优点,并且可以直接利用现有的催化裂化装置。但这一过程需要在高温的苛刻条件下进行,得到的蜡产品碳数分布较广、杂质较多,性能和色泽等方面不如直接乙烯聚合工艺的蜡产品。乙烯聚合蜡工艺则主要受限于复杂的工艺和昂贵的茂金属及非茂金属的配合物催化剂。高熔点费托蜡虽然性能优异并且技术也逐渐成熟,但其不同熔点的产品是通过不同长度碳链的精馏得到,产品是混合碳链的烷烃,仍然存在相对较宽的熔程。虽然生物质基蜡的合成研究刚起步,但其产物碳数单一,具有更窄的熔程;在合成过程中可根据需求选取特殊官能团的生物质平台小分子,还可根据特殊的使用场景对产品进行官能团化等。更重要的是,生物质基高熔点蜡更加契合世界各国的能源绿色可再生化和低碳化政策。展望了高熔点合成蜡的未来发展趋势,以期促进新的工艺和技术路线的涌现。     

高熔点蜡合成技术的研究进展

High-melting hydrocarbon waxes (melting point: > 80 ℃), consisting of saturated alkanes with carbon numbers greater than 40, exhibit unique features including high melting points, high stability, low penetration, high viscosity, as well as good wear resistance and hardness. These features make high-melting waxes suitable for use in foods, cosmetics, materials processing, electronic machinery, national defense, aviation, medical fields, etc. Considering the fast growth of technology and the electronics industry, the world's economy relies on the production and utilization of high-quality high-melting waxes. However, most waxes in the world's current markets are prepared from mineral oils, and such commercial waxes have melting points in the range of 50–70 ℃. Considering the rapid consumption of high-melting waxes and specialty waxes, their supply insufficiency is anticipated to exceed 700000 t. High-melting waxes are divided into polyethylene (PE) wax and Fischer-Tropsch synthesis (FTS) wax, based on synthesis methodology. PE wax can be obtained via the polymerization of ethylene and can also be prepared via the thermal or catalytic cracking of plastics. PE cracking to form waxes, with the advantage of low cost, can effectively solve the problem of "white pollution" and make use of existing catalytic cracking units. However, this process results in high energy consumption to achieve waste polymer depolymerization and exhibits some drawbacks, such as a wide carbon number distribution and high impurity content in the obtained PE waxes. However, there are some new methods for synthesizing PE waxes, such as cross alkane metathesis. The FTS, which uses carbon monoxide and hydrogen as raw materials, realizes the synthesis of waxes through carbon chain growth. Although the high-melting FTS waxes display excellent performance and the technology is gradually maturing, FTS waxes with different melting points are produced by rectification of products with various carbon chain lengths. Nonetheless, PE and FTS waxes are widely used in various industries because of their excellent properties. However, their synthesis is based on petroleum and coal-derived chemical products. Biomass-derived waxes have a narrow melting range due to their precise carbon chain growth process. Based on different application demands, small biomass platform molecules can be functionalized to fabricate biomass-derived waxes with special functions. More importantly, the biomass-based synthesis route is sustainable and in-line with the global values for mitigating carbon dioxide emissions and achieving carbon neutrality. This review discusses the recent advances in the synthesis techniques for high-melting waxes, including PE waxes, FTS waxes, and biomass-derived waxes. Furthermore, the catalysts and reaction mechanisms involved in the synthesis of high-melting waxes are discussed in detail. Finally, the perspectives and trends of high-melting waxes are reviewed to promote the emergence of new processes and technical routes.      

Comparative methods in the determination of wax content and pour points of crude oils

In this research, differential scanning calorimetry (DSC) and gas chromatography is used to determine the wax content of fourteen crude oils of different sources. Different empirical equations were applied to compare the wax content of crude oils. For the fourteen crude oil samples with the wax content ranging from 7.5 to 43.8 mass%, it was observed that the results of empirical equations were in good agreement with those determined by DSC and GC. Accordingly, a correlation between ASTM pour point and the temperature at which 2 mass% of wax has precipitated out from crude oil is developed.     

Lubricant properties of Moringa oil using thermal and tribological techniques

The increasing application of biobased lubricants could significantly reduce environmental pollution and contribute to the replacement of petroleum base oils. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates for use as base fluids in formulation of environment friendly lubricants. Although many vegetable oils have excellent lubricity, they often have poor oxidation and low temperature stability. Here in, we report the lubricant potential of Moringa oil, which has 74% oleic acid content and thus possess improved oxidation stability over many other natural oils. For comparison, Jatropha oil, cottonseed oil, canola oil and sunflower oil were also studied. Among these oils, Moringa oil exhibits the highest thermo-oxidative stability measured using PDSC and TG. Canola oil demonstrated superior low temperature stability as measured using cryogenic DSC, pour point and cloud point measurements. The friction and wear properties were measured using HFRR. Overall, it was concluded that Moringa oil has potential in formulation of industrial fluids for high temperature applications. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

High temperature gas chromatography for the analysis of fossil fuels: A review

For the past two or three decades geochemists have been concerned with the analyses and characterization of compounds, generally hydrocarbons, ranging from C₁? C₄₀. Significant amounts of information have resulted from these studies which have been extremely useful in many geochemical and environmental studies. However, in the past two or three years the commercial development and availability of high temperature gas chromatography columns has lead to the investigation of the occurrence and distribution of high molecular weight hydrocarbons (HMWHC), and other compounds, in the carbon number range C₄₀? C₁₀₀, present in oils, waxes, bitumens and rock extracts. The ability to study these compounds represents a major advance in organic geochemistry. In some samples these compounds may represent the bulk of the organic components but prior to development of the high temperature columns it was impossible to study their distributions. This paper will review advances that have occurred in terms of the application of high temperature gas chromatography (HTGC) to the analyses of fossil fuel samples and discuss the possible origin and significance of these compounds that have been identified. In addition, some of the potential problems involved in the analyses of these compounds will also be discussed.     

Effect of Inorganic Solids,Wax to Asphaltene Ratio,and Water Cut on the Stability of Water-in-Crude Oil Emulsions

The formation of stable water-in-crude oil emulsions during petroleum production and refinery may create sever and costly separation problems. It is very important to understand the mechanism and factors contributing to the formation and stabilization of such emulsions for both great economic and environmental development. This article investigates some of the factors controlling the stability of water-in-crude oil emulsions formed in Burgan oil field in Kuwait. Water-in-crude oil emulsion samples collected from Burgan oil filed have been used to separate asphaltenes, resins, waxes, and crude oil fractions. These fractions were used to prepare emulsion samples to study the effect of solid particles (Fe₃O₄) on the stability of emulsions samples. Results indicate that high solid content lead to higher degree of emulsion stability. Stability of emulsion samples under various waxes to asphaltenes (W/A) ratios have also been tested. These tests showed that at low W/A content, the emulsions were very stable. While at a wax to asphaltene ratio above 1 to 1, the addition of wax reduced emulsion stability. Stability of emulsion samples with varying amount of water cut has also been investigated. Results indicated that stability and hence viscosity of emulsion increases as a function of increasing the water cut until it reaches the inversion point where a sharp decline in viscosity takes place. This inversion point was found to be approximately at 50% water cut for the crude oils considered in this study.     

A novel infrared spectrophotometric method for the rapid determination of petroleum hydrocarbons, and animal and vegetable oils in water

To determine the concentrations of total oils,petroleum hydrocarbons,and animal and vegetable oils in water,the conventional analytical methods involve two scans as well as a step of magnesium silicate adsorption to remove the animal and vegetable oils in water samples.In this study,a novel analytical method was developed to determine the above oils in wastewater samples through just one scan—the concentration of animal and vegetable oils,and that of total oils were determined by measuring the absorbance of the >C=O bond in the peak area between 1750 cm and 1735 cm^-1,and of the C-H bond at 2930 cm^-1,2960 cm,and 3030 cm^-1,respectively.The concentration of petroleum hydrocarbons was then calculated by subtracting the concentration of animal and vegetable oils from that of total oils.Compared with the well-known analytical method GB/T 16488-1996,the novel approach displayed similar accuracy in the quantitative determination of oils in wastewater samples,but significantly reduced material cost and operation time.     

Polypropylene as a potential matrix for the creation of shape stabilized phase change materials

Phase change materials, based on isotactic polypropylene (PP) blended with soft and hard Fischer−Tropsch paraffin wax respectively, were studied in this paper. DSC, DMA, TGA and SEM were used to determine the structure and properties of the blends. While paraffin waxes in the blend changed state from solid to liquid, the PP matrix kept the material in a compact shape. Strong phase separation was observed in both cases, which was more pronounced in the case of soft paraffin wax. Despite the fact that both grades of paraffin wax are not miscible with PP due to different crystalline structures, it was shown that the hard Fischer−Tropsch paraffin wax is more compatible with PP than the soft one. Both waxes plasticized the PP matrix. TGA showed that PP blended with the hard Fischer−Tropsch wax degrades in just one step, whereas blends containing soft paraffin wax degrade in two distinguishable steps. SEM exposed a completely different morphology for the two paraffin waxes and confirmed the lower compatibility of PP and soft paraffin wax. The soft and hard characters of the waxes were manifested in the viscoelastic properties, where the blends containing soft paraffin wax exhibited a lower elastic modulus than pure polypropylene, whereas the hard Fisher−Tropsch paraffin wax solidified the matrix. However, both kinds of blends were able to sustain the dynamic forces applied by the DMA within five cycle runs implying good shape stability.     

The effect of sample mass and heating rate on DSC results when studying the fractional composition and oxidative stability of lube base oils

The method of dynamic microdistillation instrumented through DSC has been further elaborated and validated using distillate and residual base oils as model systems. The two major experimental factors of the method—sample mass and heating rate were varied to determine the optimal (standard) experimental conditions for better fraction resolution and thus more reliable quality assessment of petroleum products (lube oils). If these are increased, the fraction resolution ability of the method is reduced—the lighter fractions evaporate at temperatures close to those of the heavier ones, and generally all the fractions evaporate/oxidize at higher temperatures. Two major types of reactions in the heated sample were identified—the one occurring on the metal surface of the crucible leading to a polymer (lacquer) film formation and the other the oxidative cracking in the bulk of the sample leading to the formation of gaseous products. The extent of the lacquer film formation on the crucible metal surface can be reduced by increasing the heating rate and/or the sample mass, while their reduction results in better fraction resolution.     

Thermogravimetric investigations on the thermal degradation of bixin,derived from the seeds of annatto (<Emphasis Type=”Italic”>Bixa orellana L.</Emphasis>)

Conventional methods have been proposed to determine thermal properties of edible vegetable oils. The evaluation of the applicability of DSC and microwave oven (MO) methods to determine the specific heat capacities of the edible vegetable oils was performed. It was observed that the specific heat capacities of each edible oil increased as a function of the saturation of the fatty acids.