CHARACTERIZATION OF VARIOUS BITUMEN SAMPLES FROM TAR SANDS

We have investigated twenty three bitumen samples obtained using different separation methods such as: ultracentrifugation, Dean-Stark extraction, solvent extraction employing vigorous agitation, hot water separation and the Solvent Extraction Spherical Agglomeration technique. These samples were extracted from oil sand feedstocks of different grades, Suncor sludge pond tailings and mineral agglomerates obtained from the Solvent Extraction Spherical Agglomeration process. All of the bitumen samples were examined on a comparative basis using various analytical techniques. These included: fractionation into asphaltenes and maltenes; elemental analyses; molecular weight determination using vapour pressure osmometry and gel permeation chromatography, infrared, proton and 13C nuclear magnetic resonance spectroscopy. Proton and ¹³C n.m.r. spectroscopic data were used to determine the distribution of various types of hydrogens and carbons in the samples. These data were also used to derive various molecular parameters in order to investigate average molecular structures of different bitumen samples and some of their asphaltene fractions.     

13NMR CHARACTERIZATION OF HUMIC MATTER PRESENT IN DIFFERENT OIL SANDS

ABSTRACT

Insoluble organic matter (humic matter) present in oil sands can alter the wettability of the inorganic matrix and thereby cause serious problems during bitumen recovery.

Using a cold water agitation test, solids rich in organic matter were isolated from various oil sands which were chosen to reflect different behavior in the hot water extraction process.¹³C NMR examination of these separated solids showed significant structural variations between samples isolated from different oil sands. Humic matter from Utah oil sand appeared to be more aliphatic than that derived from Athabasca oil sand.

Humic acids extracted from organic rich solids as a result of prolonged treatment with 2% NaOH show remarkable similarity in their ¹³C NMR spectra. Humins differ substantially in the relative contribution of the terrestrial and marine source material. There was apparent correspondence between poor bitumen separation and the presence of humin with highly paraffinic structures.     

MINERAL MATTER AND CLAY-ORGANIC COMPLEXES IN OIL SANDS EXTRACTION PROCESSES

ABSTRACT

Differences in oil sands processability and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailings as well as carry over of water and mineral matter with the bitumen product. The nature of the organic component of clay-organic complexes extracted from various streams in an oil sands recovery process is discussed in relation to the stability of both water-in-oil and oil-in-water emulsions formed.

The samples were obtained from Suncor's oil sands extraction plant located in Fort McMurray, Alberta. Samples were obtained from throughout the extraction process from the primary froth through to the final diluted bitumen product. These samples have been studied with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) as well as with other techniques such as interfacial tension measurements. The data indicates that high water content products originate, to a great extent, from the presence of a very hydrophilic organic matrix attached to the surface of the clay and heavy metal minerals.     

The Comparison of Bitumens from Oil Sands with Different Recovery Profiles

Abstract

It has been proposed that, regardless of origin, the recovery of bitumen from oil sands is related to its viscosity. Asphaltene and resin contents are known to affect the viscosity of bitumen. In this article we compare the composition of solvent-extracted bitumens from several Athabasca oil sands with very different recovery profiles. After careful removal of any associated mineral matter by ultra-centrifugation, each bitumen sample was separated into saturate, aromatic, resin, and asphaltene (SARA) fractions by an enhanced SARA technique. The individual components were then characterized by several complementary analytical techniques, including carbon, nitrogen, nitrogen, sulfur, size exclusion chromatography molecular weight (MW_n) plus proton and ¹³C nuclear magnetic resonance spectroscopy. Based on this comparison, we see no correlation between the recovery of bitumen and its composition.     

ANALYSIS AND PHYSICO-CHEMICAL CHARACTERIZATION ON CHINESE OIL SAND BITUMENS

Abstract

The extraction of four Chinese oil sands from Sinjiang and Inner Mongolia Autonomous Regions with Dean-Stark extractor were investigated. The mineral composition and sand grain distribution were determined and the bitumens were separated into saturates, aromatics, resin-I and resin-II, asphaltenes. The structure parameters and molecular model were made for the bitumens. Elemental analysis, molecular weight, FTIR, 1H-NMR were made for the bitumen fractions. The results show that the molecular structure of Mongolia bitumens have more polycyclic aromatics than that of Sinjiang bitumen. It is believed that the extraction of Sinjiang oil sand bitumen by hot alkaline water is much easier than Mongolia oil sand due to the difference of the viscosity of bitumen, the molecular structure and other physico-chemical properties of the bitumens.     

ISOLATION AND CHARACTERIZATION OF NATURAL SURFACTANTS FROM CHINESE OIL SAND BITUMENS

Abstract

Natural surfactants(NS) have been isolated from four Chinese oil sand bitumens (NNY,NSY,SNE,SUG) using the method of solvent extraction. These compounds were analyzed by IR and their interfacial tension (γ) against pH were measured. The results were compared with these obtained for fractions separated from the bitumen by conventional methods. The factors of NS to the extraction of bitumen from oil sand by hot water were investigated.     

Novel Impact of Wet Dosages of NMP in Extraction for Production of High BMCI Carbon Black Feedstocks

Abstract

In separation sciences, “Solvent Extraction” is one of the most important unit operations, a very widely used process, next only to distillation. In the petroleum refining industry, solvent extraction is commonly widely applied to produce a number of specialty products such as BTX, lube base oils, waxes, etc. There are many solvents used in various separation processes, like sulfolane, phenol, furfural, ketones, and N-methyl pyrollidone (NMP). NMP in particular is an environmentally benign, new generation solvent, which can be tailored for specific separations by using it in conjunction with small doses of water. In recent years, researchers are re-looking at the separation processes and their modifications to exploit these for producing high-value industrial products from low-value refinery streams. The present study deals with the production of high-quality carbon black feedstocks (CBFS) from clarified oils. The study shows the beneficial effect of using NMP in combination with different dosages of water as extraction solvent to extract low-value clarified oil, a cracked material from the FCC unit of an operating Indian refinery. In the present study, water ranging from 0.3 wt% to 10 wt% was used with NMP to produce aromatic extract of BMCI (Bureau of Mines Correlation Index) up to 146 through liquid-liquid equilibrium and mass transfer studies on clarified oil (CLO). The effect of solvent-to-feed ratio at constant temperature on solvent extraction was also studied. The addition of water in NMP alters the “selectivity” of solvent, which can be exploited for producing aromatic extracts of a wide range of BMCI for different end-use applications. The major users of such high BMCI extracts are carbon black and electrode pitch manufacturers. Regression analysis was also done to develop correlations between water percentage in NMP and targeted BMCI of aromatic extract. Presently, CLO is blended with fuel oil and sold as a very low value product in refinery. Since the demand of CBFS is increasing continuously and current short-fall in India is met through imports from China, Korea, and Japan, it is desirable that such studies are undertaken and will lead to production of high-value CBFS from low-value refinery streams through separation processes.     

The Use of Microscopic Bitumen Froth Morphology for the Identification of Problem Oil Sand Ores

Abstract

Oil sand, which is found in various deposits around the world, consists mostly of sand, surrounded by up to 18 wt% bitumen. The largest deposits known are situated in northern Alberta, Canada, where reserves of bitumen are estimated to be 1.7 trillion barrels. Bitumen is similar to heavy oil, but with much higher viscosity and density. The two main commercial oil sand operations in Alberta are surface mines and use aqueous flotation of the bitumen to separate it from the rest of the oil sand. Under optimal conditions up to 95% of the bitumen can be recovered, but occasionally ores are mined that create problems in extraction, and recovery can drop to 70% or less. This article discusses the microscopic morphologies of various bitumen and heavy oil streams and their relationship to processing problems. The results of extensive microscopic work have demonstrated that the bitumen in an oil sand ore is the phase most susceptible to oxidation and that the resulting changes manifest themselves in particular microscopic structures. The presence and type of these structures can be related to the processing behavior of oil sand ores. Morphological features found in froths from commercial operations are similar to those found in froths from laboratory-prepared samples. The morphological features found in froths of oxidized ores have been categorized and quantified for a variety of samples and are referred to as degraded bitumen structures. Experiments in which fresh oil sand ores were subjected to low-temperature oxidation showed that bitumen froth morphology changed dramatically compared to that of nonoxidized ores for identical bulk compositions and extraction water chemistries.     

QUANTIFICATION OF BITUMEN PARTICLES IN AEROSOL AND SOIL SAMPLES USING HP-GPC

ABSTRACT

A method for identifying and quantifying bitumen particles, generated from the wear of roadway asphalts, in aerosol and soil samples has been developed. Bitumen is found to be the only contributor to airborne particles containing organic molecules with molecular weights larger than 2000 g pr. mol. These are separated and identified using High Performance Gel Permeation Chromatography (HP-GPC) with fluorescence detection. As an additional detection method Infra Red spectrometry (IR) is employed for selected samples, The methods have been used on aerosol, soil and other samples.     

VISCOSITY AND SOLUBILITY OF MIXTURES OF BITUMEN AND SOLVENT

Abstract

The solubilities of three bitumen samples (Suncor, Syncrude and Lloydminster) in five solvents were examined and prediction on the various bitumen-solvent mixture viscosities were made with Cragoe equation. By calculating the Cragoe constant ‘a’ for each mixture and using the average value in the Cragoe equation the prediction accuracy of the equation was improved by over 60%. Bitumen-naphtha mixtures showed the best viscosity prediction characteristics.

The solubility of the asphaltenes in the bitumen was highest in toluene among the five solvents However, naphtha, showed a moderate solvating power, which negligibly varied over the range of composition studied. Therefore naphtha, a solvent derived from bitumen was recommended as the most appropriate solvent for reducing the viscosity bitumen.     

13NMR CHARACTERIZATION OF HUMIC MATTER PRESENT IN DIFFERENT OIL SANDS

Insoluble organic matter (humic matter) present in oil sands can alter the wettability of the inorganic matrix and thereby cause serious problems during bitumen recovery.

Using a cold water agitation test, solids rich in organic matter were isolated from various oil sands which were chosen to reflect different behavior in the hot water extraction process.¹³C NMR examination of these separated solids showed significant structural variations between samples isolated from different oil sands. Humic matter from Utah oil sand appeared to be more aliphatic than that derived from Athabasca oil sand.

Humic acids extracted from organic rich solids as a result of prolonged treatment with 2% NaOH show remarkable similarity in their ¹³C NMR spectra. Humins differ substantially in the relative contribution of the terrestrial and marine source material. There was apparent correspondence between poor bitumen separation and the presence of humin with highly paraffinic structures.     

MANAGEMENT OF OIL SANDS TAILINGS

ABSTRACT

In Alberta, oil sands bitumen is utilized for synthetic crude oil (SCO) production by surface mining, bitumen extraction followed by primary (coking) and secondary (catalytic hydrotreating) upgrading processes. SCO is further refined in specially designed or slightly modified conventional refineries into transportation fuels. Oil sands tailings, composed of water, sands, silt, clay and residual bitumen, is produced as a byproduct of the bitumen extraction process. The tailings have poor consolidation and water release characteristics. For twenty years, significant research has been performed to improve the consolidation and water release characteristics of the tailings. Several processes were developed for the management of oil sands tailings, resulting in different recovered water characteristics, consolidation rates and consolidated solid characteristics. These processes may affect the performance of the overall plant operations. Apex Engineering Inc. (AEI) has been developing a process for the same purpose. In this process oil sands tailings are treated with Ca(OH)₂ lime and CO₂ and thickened using a suitable thickener. The combination of chemical treatment and the use of a thickener results in the release of process water in short retention times without accumulation of any ions in the recovered water. This makes it possible to recycle the recovered water, probably after a chemical treatment, as warm as possible, which improves the thermal efficiency of the extraction process. The AEI Process can be applied in many different fashions for the management of different fractions of the tailings effluent, depending on the overall plant operating priorities.     

CHARACTERIZATION OF OIL SANDS MINERAL COMPONENTS AND CLAY-ORGANIC COMPLEXES

ABSTRACT

Differences in oil sands processability and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailings as well as carry over of water and mineral matter with the product. The nature of the organic component of clay-organic complexes extracted from various streams in an oil sands recovery process is discussed in relation to the stability of both water-in-oil and oil-in-water emulsions formed. These samples have been studied with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) as veil as with other techniques such as interfacial tension measurements.     

DEMINERALIZATION OF PETROLEUM COKES AND FLY ASH SAMPLES OBTAINED FROM THE UPGRADING OF ATHABASCA OIL SANDS BITUMEN

ABSTRACT

Ash reduction of the cokes and fly ash samples derived from the Athabasca oil sands bitumen was attempted by dissolving the mineral matter in acids. The samples used for this investigation included Syncrude fluid coking coke, Suncor delayed coking coke and the two fly ash samples obtained from the combustion of these cokes. All samples were analyzed for C,H,N,0 and S before and after acid demineralization and the analyses results compared. Further, the ash from the samples before and after acid demineralization was analyzed for silica, alumina, iron, titanium, nickel and vanadium to assess the acid leaching of these elements. CP/ MAS, ¹³C NMR spectroscopic study of the demineralized coke and fly ash samples was also attempted     

CHARACTERIZATION AMD POTENTIAL UTILIZATION OF WHITEROCKS (DTAB) TAR SAND BITUMEN II. PYROLYSIS MASS SPECTROMETRY AND NUCLEAR MAGNETIC RESONANCE ANALYSES

ABSTRACT

The proton and carbon-13 nuclear magnetic resonance characteristics of the native Whiterocks bitumen were determined by comparing the spectra of the samples to literature assignments. The tentative structural assignments of pyrolysis products were also obtained from the spectra of Curie-point low voltage mass spectrometric analysis. The results obtained from proton and carbon-13 nuclear magnetic resonance and pyrolysis-mass spectrometry analysis suggested that the native bitumen consists mostly of short- and long-chain (i.e., normal and isoprenoid chains) alkylsubstituents attached to polycyclic naphthenic, naphtheno-aromatic and/or aromatic moieties.     

Role of Structure and Acidic Nature on Catalytic Behavior of Nickel Supported H-mordenite,H-ZSM-5, and γ–alumina Catalysts

Abstract

Nickel metal was loaded in different percentages (7, 10, and 13% w/w) on different supports (H-mordenite, H-ZSM-5, and γ–alumina). The prepared catalyst samples were tested in cyclohexane conversion using microreactor pulse technique. Structure was followed up by XRD analysis. Chemisorption of tert-butylamine (TBA) was adopted for estimating the number of surface acid sites. It was found that all prepared samples displayed cracking activity, being mostly related to the fraction of acid sites remaining on the surface after coverage with supported Ni atoms. H-mordenite-supported samples exhibited mainly isomerization functionality by showing a larger portion of surface acid sites. H-ZSM-5-supported samples showed higher dehydrogenation activity. Agglomeration seemed to be responsible for lower activity of the sample of higher Ni content. The formed NiOOH phase was suggested to be responsible for increased dehydrogenation activity on H-ZSM-5 samples and increased cracking activity on γ–alumina-supported samples of higher Ni content.     

The effect of different solvents on the density of undersaturated athabasca bitumen: Application in VAPEX and ES-SAGD

Predicting the density of bitumen after solvent injection is highly required in solvent-based recovery techniques like expanding solvent-steam assisted gravity drainage (ES-SAGD) and vapor extraction (VAPEX) in order to estimate the cumulative oil recovery by these processes. Using experimental procedures for this purpose is so expensive and time-consuming; therefore, it is crucial to propose a rapid and accurate model for predicting the effect of various solvents on the dilution of bitumen. In this study, an adaptive neuro-fuzzy interference system is introduced to estimate the effect of methane, ethane, propane, butane, carbon dioxide, and n-hexane on the density of undersaturated Athabasca bitumen in wide ranges of operating conditions. The obtained results were in an excellent agreement with experimental data with coefficients of determination (R²) of 0.99997 and 0.99948 for training and testing datasets, respectively. Statistical analyses illustrate the superiority of the proposed model in predicting the bitumen density at different conditions.     

CHARACTERIZATION OF SOLVENT-INSOLUBLE ORGANIC MATTER ASSOCIATED WITH MINERAL MATTER FROM OIL SANDS∗

ABSTRACT

Considerable quantities of insoluble organic matter (IOM) are known to be associated with certain solid fractions found in oil sands. This organic matter is believed to be partly responsible for the intractability of the sludge generated by the hot water process used for the extraction of bitumen from Alberta oil sands. In previous investigations we had attempted to enrich the insoluble organic matter by dissolving the minerals in concentrated HCl/HF mixtures. As a result of this severe acid treatment the inorganic material is decomposed, but the organic constituents are also likely to undergo significant changes. In the present work we have used a milder HCl/HF treatment for mineral dissolution. The results from the current investigation are compared with the results of the previous study to assess the chemical alterations of the organic matter resulting from the two treatments.

The fractions obtained from the mild acid treatment were analyzed using solid state ¹³C NMR spectroscopy and elemental analysis. Latter results have been discussed in terms of a van Krevelen diagram which is derived by plotting the atomic H/C ratios against O/C. The NMR data were used to calculate the aromaticities of the various organic fractions. Based on the elemental compositions and the NMR data, it is suggested that the IOM associated with the sludge solids is derived from terrestrial sources.     

Spectroscopic Characterization of Asphaltene Fraction of Nigerian Bitumen

This research article offers data on the spectroscopic elucidation of the asphaltene fraction of Nigerian bitumen in order to establish its features that might aid the developmental processes of the fossil fuel. Bitumen was extracted from the oil sands obtained from six locations where there were oil sand out-crops in Southwestern Nigeria using toluene via Soxhlet extraction and then deasphalted using n-pentane. The organic components of the precipitated asphaltenes were investigated using Fourier transform infrared spectrometry, while the elemental contents were determined using Inductively coupled plasma atomic emission spectroscopy and carbon/nitrogen analyzer. The results revealed that the average content (29.15 wt%) of Nigerian bitumen asphaltenes was less than that of Athabasca (40.10 wt%) but slightly higher than that of Cold Lake bitumen (24.40 wt%). The IR spectra of the asphaltenes indicated the presence of various organics and heteroatoms corroborating that asphaltenes composed of high molecular weight polycyclic constituents comprising of nitrogen, sulfur, and oxygen heteroatoms. The results indicated that the values of Cr, Cu, Fe, Mn, Ni, S, V, and Zn were comparatively higher in the asphaltenes than the parent bitumen due to the presence of comparatively high levels of porphyrins in the asphaltenes than the bitumen, while the concentrations of all the elements were higher in the Nigerian bitumen asphaltene than Nigerian crude oil asphaltene (except S and C). Cross plot analysis result between the asphaltenes and bitumen using their elemental mean concentrations as variables indicates that significant and positive correlation (R² = 0.975) exists between them, indicating very strong interelement and geochemical relationships between them. The elements showed close clustering, indicating similar sources because the elements were known to associate with petroleum hydrocarbon formation. Also, apart from N, S, and C, other elements are transition metals with similar chemical affinity.     

A DIMENSIONAL ANALYSIS OF DISSOLUTIONS OF A BITUMEN CONCENTRATE DERIVED FROM UTAH TAR SAND

ABSTRACT

Dissolution of bitumen concentrate derived from Utah tar sand by hot-water separation was studied in a stirred-tank reactor. The dissolution constitutes an important step in the bitumen concentrate clean-up process. A dimensional analysis was performed for the system which was utilized to construct a number of bitumen concentrate dissolution maps from the experimental data.