New method for obtaining the distillation curves of petroleum products and coal-derived liquids using a small amount of sample

Based on thermogravimetric principles a new distillation method for petroleum products and coal-derived liquids has been developed. The boiling point distributions of five petroleum fractions (kerosene; 128–228 °C; light gas oil, 178–298 °C; middle gas oil, 200–360 °C; vacuum gas oil, 268–565 °C; and high vacuum gas oil, 305–604 °C) and one highly aromatic coal-tar fraction (wash oil, 180–310 °C) were obtained. The results are in good agreement with those obtained by standard (ASTM) distillation methods. The amount of sample required is very small (≈10 mg) and can be solid or liquid. The experiments at normal pressure were carried out using a specially designed sample holder made of quartz. In the case of high-boiling-point fractions (distillation under reduced pressure) a normal sample holder can be used. The results are automatically recorded as temperature versus weight loss.     

Estimation of total aromatics in kerosene fractions by infrared spectroscopy: I

A faster and accurate infrared method for estimating total aromatics in petroleum samples boiling in the kerosene range (140–250°C) was developed using pure aromatic concentrate from kerosene as reference material. The limitations of a synthetic mixture of pure compounds used as reference are also discussed. The accuracy of results is found to be dependent on the closeness of the average absorptivity at a characteristic wave number (1600 cm^?1) of an unknown sample and kerosene used as reference. The results obtained from the proposed method on kerosene fractions of Bombay High are compared, as an illustration, with those obtained by FIA.     

Structural characterization of Saudi Arabian heavy crude oil by n.m.r. spectroscopy

Saudi Arabian heavy crude oil was separated into six fractions, including five distillate fractions (<93, 93–204, 204–260, 260–343 and 343–454 °C) and a >454 °C distillation residue. Each fraction was analysed by ¹H and ¹³C n.m.r. spectroscopy, and combined gained information from these analyses provided reliable average structural parameters. These included estimation of aliphatic and aromatic content, average paraffinic chain length, and estimation of hydrogen, methyl and alkyl bearing aromatic carbons for each of the six fractions. The extent of branching in paraffinic chains and amount of aromatic bridgehead carbons were also calculated.     

Intensification of the processes of dehydrogenation and dewaxing of middle distillate fractions by redistribution of hydrogen between the units

The dehydrogenation and dewaxing of hydrocarbons of middle-distillate fractions, which proceed in the hydrogen medium, are of great importance in the petrochemical and oil refining industries. They increase oil refining depth and allow producing gasoline, kerosene, and diesel fractions used in the production of hydrocarbon fuels, polymer materials, synthetic detergents, rubbers, etc. Herewith, in the process of dehydrogenation of hydrocarbons of middle distillate fractions (C₉–C₁₄) hydrogen is formed in the reactions between hydrocarbons, and the excess of hydrogen slows the target reaction of olefin formation and causes the shift of thermodynamic equilibrium to the initial substances. Meanwhile, in the process of hydrodewaxing of hydrocarbons of middle distillate fractions (C₅–C₂₇), conversely, hydrogen is a required reagent in the target reaction of hydrocracking of long-chain paraffins, which ensures required feedstock conversion for production of low-freezing diesel fuels. Therefore, in this study we suggest the approach of intensification of the processes of dehydrogenation and dewaxing of middle distillate fractions by means of redistribution of hydrogen between the two units on the base of the influence of hydrogen on the hydrocarbon transformations using mathematical models. In this study we found that with increasing the temperature from 470 °C to 490 °C and decreasing the hydrogen/feedstock molar ratio in the range of 8.5/1.0 to 6.0/1.0 in the dehydrogenation reactor, the production of olefins increased by 1.45–1.55%wt, which makes it possible to reduce hydrogen consumption by 25,000 Nm³/h. Involvement of this additionally available hydrogen in the amount from 10,000 to 50,000 Nm³/h in the dewaxing reactor allows increasing the depth of hydrocracking of long-chain paraffins of middle distillate fractions, and, consequently improving low-temperature properties of produced diesel fraction. In such a way cloud temperature and freezing temperature of produced diesel fraction decrease by 1–4 °C and 10–25 °C (at the temperature of 300 °C and 340 °C respectively). However, when the molar ratio hydrogen/hydrocarbons decreases from 8.5/1.0 to 6.0/1.0 the yield of side products in the dehydrogenation reactor increases: the yield of diolefins increases by 0.1–0.15%wt, the yield of coke increases by 0.07–0.18%wt depending on the feedstock composition, which is due to decrease in the content of hydrogen, which hydrogenates intermediate products of condensation (the coke of amorphous structure). This effect can be compensated by additional water supply in the dehydrogenation reactor, which oxidizes the intermediate products of condensation, preventing catalyst deactivation by coke. The calculations with the use of the model showed that at the supply of water by increasing portions simultaneously with temperature rise, the content of coke on the catalyst by the end of the production cycle comprises 1.25–1.56%wt depending on the feedstock composition, which is by 0.3–0.6%wt lower that in the regime without water supply.     

Characterization of the highest optically active fraction of shale oil

A shale oil sample from an above-ground 150 ton retort, designed to simulate the in-situ retort process, was vacuum distilled to obtain narrow distillate fractions. The optical rotation was measured for each distillate cut. The fraction with the highest optical rotation (470 °–485 °C) was subjected to elution chromatography using hexane, benzene and methanol, respectively. The resulting saturated fraction (hexane cut) was investigated by computerized gas chromatography-mass spectrometry. Three steranes, four pentacyclic triterpanes and five normal alkanes were identified, and the partial structures of two other compounds have been suggested.     

Fractionation of squalene from amaranth seed oil

Amaranth seed oil was fractionated in a bench-scale short-path distillation unit to obtain fractions rich in squalene. Fractionations were conducted with degummed amaranth oil, alkali-refined amaranth oil, and simulated amaranth oil. Squalene concentration was increased about sevenfold with a squalene recovery of 76.0% in the distillate when degummed amaranth oil was fractionated at 180°C and 3 mtorr vacuum. Free fatty acids codistilled with squalene, lowering the squalene content of the distillate, and resulted in a semisolid distillate at room temperature. Alkali-refining was subsequently used to reduce the free fatty acid content before fractionation. A simulated oil (7% squalene/93% soybean oil) and alkali-refined amaranth oil were fractionated at three temperatures (160, 170, and 180°C) and five vacuum settings (10, 100, 200, 400, and 600 mtorr). The highest squalene recoveries from simulated oil and alkali-refined amaranth oil were 73.4 and 67.8%, respectively, both at 180°C and 100 mtorr, which translates to 12.1-and 9.2-fold increases in squalene concentration, respectively. The squalene recovery of the alkali-refined amaranth oil at 180°C was not significantly different at 10 mtorr vs. 100 mtorr. The results of this study can be used as a component to assess the economic feasibility of fractionating amaranth seed for starch, oil, meal, and squalene.     

Solvent Crystallization of the Fat and Fatty Acids of Schleichera trijuga Seed

The crystallizations of the kusum oil and the mixed fatty acids thereof were studied from several solvents at various temperatures (+10° C to ?60° C). The results indicate in general that in the range of temperatures studied, petroleum ether as a single solvent is comparable in efficiency to methanol and superior to both acetone and ethanol in respect of separation of the saturated and unsaturated components of the fatty acid mixture. The saturated and unsaturated fractions of the oil also are better separated by petroleum ether than acetone. Further, oleic acid essentially free from linoleic acid is obtainable by a preliminary crystallization of the fatty acid mixture from petroleum ether at ca. ?12° C, followed by two additional crystallizations from acetone at ca. ?55° C.     

Liquid fuels fromMesua ferrea L. seed oil

Mesua ferrea L. seed oil consists of triglycerides of linoleic, oleic, palmitic and stearic acids. These acids were pyrolyzed separately in the presence of different amounts of solid sodium carbonate. Pyrolysis experiments revealed that linoleic and oleic acids can be converted to hydrocarbons of a wide range of molecular weights by pyrolyzing them with even 1% by wt of sodium carbonate up to a temperature of 500°C, whereas palmitic and stearic acids can be converted to hydrocarbons only by pyrolyzing them with equivalent amounts or more of sodium carbonate up to a temperature of about 650°C. The fractions of boiling range 60–320°C of all of the pyrolytic oils were analyzed for their hydrocarbon types by the method of fluorescent indicator adsorption (FIA). The aromatic contents of the pyrolytic oils of linoleic and oleic acids were found to be much higher than those of palmitic and stearic acids. GS and GC-MS analyses of all the saturate fractions indicated mainly normal alkanes with a carbon number range of 6 to 17.     

Chemical composition of the distillate fractions of coal tar from OAO Altai-Koks

The chemical composition of the distillate fractions with boiling points of to 180, 180–230, and 230–280°C separated from undehydrated coal tar from OAO Altai-Koks was studied by gas chromatography-mass spectrometry. A list of identified aromatic compounds (including N-, O-, and S-containing compounds) and their alkyl derivatives is given. It was found that, upon the complete processing of tar with the recirculation of residual raw materials at the stage of coking and its hydrogenation refining in the presence of suspended Mo- and Ni-containing catalysts and a hydrogen donor (tetralin), the yields of chemical products were the following (wt %): coke, 50–55; absorption oil, 9–12; benzene, naphthalene, tetralin, dimethylnaphthalenes, and other hydrocarbons, 25–30; BTX fraction 4–5; and C₁-C₄ and CO₂, 10–12.     

Structural characteristics of petroleum sludge

The structural characteristics of dewatered petroleum sludge and the fraction boiling above 350°C are compared, on the basis of physicochemical research methods. The structure of the residue boiling above 350°C is more aromatic than the initial sludge and resembles that of heavy petroleum residues. This suggests that hydroconversion of the >350°C fraction and the heavy petroleum residues will also be similar. Hence, the sludge component boiling above 350°C may prospectively be processed by hydroconversion in the presence of ultrafine catalysts.     

A procedure for quantitative 13c-n.m.r. application to the characterisation of the naphtha fraction of petroleum crude

A method for optimising the conditions for the quantitative ¹³C-n.m.r. measurement is suggested and has been applied to the compositional studies of naphtha fractions (50–100°C and 100–150°C) of Darius crude oil. The novelty of the method is that we can pre-estimate the pulse repetition time for unknown samples. It has been shown that the various compositional parameters thus obtained are in satisfactory agreement with those obtained from the elemental analysis, fluorescent indicator adsorption (FIA) and ¹H-n.m.r. spectrometry.     

Isolation and Evaluation of Stearin and Olein Fractions from Rice Bran Oil Fatty Acid Distillate by Detergent Fractionation and Conversion into Neutral Glycerides by Autocatalytic Esterification Reaction

Detergent fractionation (Lanza process) offers a valuable separation process for edible oils that contain varying amounts of saturated and unsaturated fatty acids. The rice bran oil fatty acid distillate (RBOFAD), obtained as a major byproduct of rice bran oil deacidification refining process, was fractionated by detergent solution into a fatty acid mixture as follows: low-melting (19.00 °C) fraction of fatty acids as olein fraction (44.50 g/100 g) and high-melting (49.00 °C) fatty acids as stearin fraction (37.15 g/100 g). A high amount of palmitic acid (42.75 wt%) is present in stearin fraction, while oleic acid is higher (48.21 wt%) in the olein fraction. The stearin and olein fractions of RBOFAD with very high content of free fatty acids are converted into neutral glycerides by autocatalytic esterification reaction with a theoretical amount of glycerol at high temperatures (130–230 °C) and at a reduced pressure (30 mmHg). Acid value, peroxide value, saponification value, and unsaponifiable matters are important analytical parameters to identity for quality assurance. These neutral glyceride-rich stearin and olein fractions, along with unsaponifiable matters, can be used as nutritionally and functionally superior quality food ingredients in margarine and in baked goods as shortenings.     

Short‐path distillation of palm olein and characterization of products

Short‐path distillation (SPD) has been a technique used to purify products containing monoacylglycerols (MAG), diacylglycerols (DAG), etc. Palm oil and its fractions contain high contents of DAG, typically 5–8%, some of which have significant effects on the crystallization behavior of the fats. A possible way of reducing the DAG to lower levels using SPD is evaluated. Distillation of refined, bleached and deodorized palm olein was performed at different temperatures (220–250 °C) and flow rates (500 and 1000 g/h). Feed oil, residue oil and distillates were characterized in terms of composition and melting and cooling behavior. The DAG content of the feed oil was 6.5%. At high evaporating temperatures, the free fatty acid (FFA) concentration in the residue oil and the distillate oil decreased for the same flow rate. Increasing the feed flow rate while maintaining constant temperature led to a greater FFA concentration in both streams. The DAG content in the distillate increased at higher temperature, reaching 68% at 250 °C, while the residue oil achieved a level of 2.8% at lower flow feeding rates. Melting and cooling behavior were influenced by the composition of DAG and triacylglycerols. Thus, the distillate oils had higher melting profiles in contrast to the feed oil and the residue oil, which had similar profiles despite the removal of higher‐melting components.     

Reduction of Polycyclic Aromatic Hydrocarbons from Thermal Clay Recycled Oils Using Technical Adsorbents

In Italy recycled oils are obtained by treating exhaust oils by deasphaltation, redistillation and subsequent thermal clay processing. PAH concentrations of intermediate and finished products were found to be 1200, 285, 420, and 275, 126 and 60 A. U. (FDA method, sun test), respectively for light, medium and heavy distillation fractions of intermediate and finished products. The polynuclear fractions of all intermediate products and of the light fraction of finished products from exhaust oils exceeded HSE (Health, Safety, Environment) standards. Because the light distillate intermediate product gave the highest FDA value (1200 A. U.), laboratory purification tests were carried out on it using four technical adsorbing substances (two active carbons, alumina, silica gel) with an adsorbent/oil ratio of 5/100. No reduction of the PAH fraction was found after oil percolation at room temperature (26°C). Oil treatment as indicated above for 30 minutes at 100°C gave a reduction of FDA values for the light distillate of about 50% using several vegetal active carbons, PAH content were found to be less reduced with silica gel and alumina (32% and 12% reduction, respectively). In any case, the FDA values of active carbon treated oils remained >200 A.U˙˙ The light product which had already undergone thermal clay processing was treated using between 0.5% and 3% of adsorbent in the mix, at 120–265 C, with oil/adsorbent contact times of up to 2 hours. After treatment, the FDA values of most oils fell to below 200 A.U, and the best PAH reduction (about 70%) was obtained with 3% active carbon at temperatures between 120 and 200°C. On the basis of these results, the light oil fraction obtained from thermal clay processing and its 6 samples after treatment with active carbon were tested for compliance with Health Safety Environment standards (viz, FDA <200 A. U., PAF<2%, Total PAH<100 ppm and M.I.<1.0). The best conditions for reducing residual PAH in light fraction of recycled oils are the treatment with active carbon at concentrations between 1% and 3% with 120 °C temperature contact time of about 1 hour.     

Thermocatalytic treatment of petroleum residues in the presence of zeolites and oil shale

Thermolysis of atmospheric and vacuum residua in the presence of both organomineral activators and zeolites, solid Broñsted acids, was studied. It was shown that the thermolysis of heavy petroleum residues is a thermocatalytic process that occurs under relatively mild conditions (415–425°C). Oil shale and/or zeolite admixtures act as both a catalyst for the process and a coke adsorbent. Under optimal conditions (415–425°C, 50 min, 10–12% shale), light petroleum fractions boiling in the motor-gasoline and diesel ranges can be obtained from atmospheric and vacuum residua with a yield up to 60 wt %.     

Die Dünnschicht-Chromatographie in der Wachsanalytik: Die Identifizierung der Wachsalkohole und -säuren

Thin-layer Chromatography in the Wax Analysis: The Identification of Wax Alcohols and Acids A thin-layer chromatographic method employing the following conditions has been developed for the separation of wax alcohols and acids. Adsorbent: Kieselgur G; impregnating solution: 0.5 vol% silicon oil + 10 vol% tetradecane in petroleum ether; stationary phase: tetradecane-silicon oil (Bayer PN 1000); C₁₄ to C₂₄: temperature 42° C; mobile phase: 90 vol% acetic acid, which is completely saturated with pure tetradecane at 42° C; C₂₂ to C₄₀: temperature 60° C; mobile phase: 96 vol% acetic acid, which is completely saturated with pure tetradecane at 60° C; detecting agent: 10% aqueous sodium hydroxide solution mixed with an equal volume of 0.1 molar (1.6%) aqueous potassium permanganate solution.     

Composition of petroleum heavy ends. 3. Comparison of the composition of high-boiling petroleum distillates and petroleum >675 °C residues

Three ‘heavy ends’ fractions of petroleum are compared and defined as 370–535 °C distillates, 535–675 °C distillates, and >675 °C residues. The distributions of classes of compounds, compound types, molecular weights, and heteroatom content of individual molecules in the heavy ends fractions are discussed.     

Composition of oily components in the liquid products of the supercritical fluid extraction of oil shale from the Chim-Loptyugskoe deposit

The compositions of hydrocarbon and heteroorganic compounds in the oily components of the liquefaction products of oil shale sampled from the Chim-Loptyugskoe deposit have been investigated in benzene under supercritical conditions in temperature ranges up to 200, 200–300, and 300–400°C. It has been found that they consisted of normal and branched-chain alkanes, including unsaturated isoprenoids; alkenes, saturated and unsaturated naphthenes; mono-, bi-, tri-, tetra-, and pentacyclic aromatic hydrocarbons; compounds from the thiophene and benzo-, dibenzo-, and naphthobenzothiophene series; and aliphatic esters and ketones.     

Catalytic hydroliquefaction of Barzass liptobiolitic coal in a petroleum residue as a solvent

Hydrogenation of liptobiolitic coal from the Barzas Pit (Russia) in a petroleum residue as a solvent was investigated in the presence of an iron containing ore catalyst at 400–430 °C and working pressure 7.1 MPa. Near 94–97% of the coal organic mass was converted into gaseous and liquid products. The addition of the catalyst in amount of 5% to the coal mass increases the degree of the coal conversion by 21–23 wt%. Under these conditions, the yield of hydrocarbon light liquid products (bp<200 °C) was increased up to 24–28 wt%. The distillate products consist mainly of paraffins, while most part of the aromatic hydrocarbons are alkylbenzenes.     

Identification of Sulfur‐Containing Impurities in Biodiesel Produced From Brown Grease

Fatty acid methyl esters (FAME) from waste grease usually contain higher concentrations of sulfur (S) than allowed to meet the specified quality standard for biodiesel (<15 ppm). Brown grease lipid‐derived FAME was produced and fractionated by two passes through a wiped‐film evaporator (WFE) to produce three fractions: (1) a 120 °C pass distillate, (2) a 170 °C pass distillate, and (3) a heavy residue. Solid phase extraction (SPE) was used to concentrate the S species from the distillate fractions so that they could be detected by a gas chromatography–pulsed flame photometric detector (GC–PFPD) and GC–mass spectrometry (MS). The ethyl acetate and methanol (MeOH) fractions obtained by SPE of the 120 °C WFE distillate and methyl tert‐butyl ether and acetone fractions obtained by SPE of the 170 °C WFE distillate had the highest concentration of S and were, therefore, the best candidates for GC–PFPD analysis. GC–PFPD methods were developed to separate the S species adequately enough for those peaks to be analyzed by GC–MS which matched fragmentation patterns identified by the MS chemical library as tetrahydrothiophenes, dithiolanes, and thiophenes. MS fragmentation patterns were used to identify other, larger, S‐bearing species as sulfides and disulfides cross‐linking between two FAME molecules. The results obtained from this study provide a foundation for developing effective purification methods to remove S‐containing impurities from waste grease‐derived biodiesel.