Canadian Oil Sand Bitumen Research Articles

Fundamental study of the integrated process of heavy oil pyrolysis and coke gasification. Part Ⅰ: Effect of CO and H2 in syngas atmosphere on heavy oil pyrolysis

An integrated process of heavy oil pyrolysis and coke gasification was proposed to realize the in-situ gasification of coke and provide syngas (CO/H2) atmosphere for heavy oil pyrolysis to obtain high-quality liquid products. To reveal the reaction mechanism of syngas (CO/H2) on heavy oil pyrolysis, the pyrolysis characterizations of three heavy oils including Dagang slurry oil (DG-SO), Qingdao vacuum residue (QD-VR) and Canadian oil-sands bitumen (CA-OB) were evaluated at different atmospheres (N2, CO, CO/H2, and H2). The results showed that compared with QD-VR and CA-OB, DG-SO with high content of aromatics but high Conradson carbon residue (CCR) value was not suitable for the integrated process of heavy oil pyrolysis and coke gasification. Compared with the N2 atmosphere, the pyrolysis oil yields of DG-SO, QD-VR, and CA-OB increased in turn under CO, CO/H2, and H2 atmospheres. On the contrary, their coke and gas yields decreased in turn. Furthermore, the contents of CH4, C2-C5, and CO2 in pyrolysis gases all decreased in turn, while the contents of their alkane, olefin, aromatic hydrocarbon, and oxygen /nitrogen/sulfur compounds in pyrolysis oil increased in turn. The change of oil and gas composition indicated that compared with N2, both CO and H2 could inhibit further decomposition of liquid products. The reactivity of coke showed that CO and H2 could reduce the degree of condensation of coke to increase its reactivity, but the effect of CO was not as good as that of H2.

Impact of co-feeding cracked light products on visbreaking of vacuum residue deasphalted oil

The impact of co-feeding light cracked products on thermal conversion was investigated due to reports that indicated suppression of coking and other benefits during such operation. Specific attention was paid to n-pentane insoluble asphaltenes content and formation. In this study all reactions were performed at 400 °C and 2 MPa initial nitrogen pressure, using a vacuum residue deasphalted oil obtained from Canadian oilsands bitumen. The impact of co-feeding distilled cracked naphtha and kerosene at 5 to 15 wt% was studied. Control reactions included self-reactions of all materials and reactions where the vacuum residue deasphalted oil was replaced by naphthalene. The presence of the distilled cracked naphtha and kerosene did not cause an observable change in the progression of the thermal reaction and no conclusive evidence was found that the development of n-pentane insoluble material in the products was reduced. The reactions products showed no relationship between n-pentane insoluble content, vacuum residue conversion and free radical content. In control experiments the conversion of distilled cracked naphtha and kerosene in naphthalene caused the formation on n-pentane insoluble material, which was not observed during self-reaction of these materials. The results suggested that some of the naphthalene was directly thermally alkylated at 400 °C and that at least some of the resulting products became n-pentane insoluble.

Visbreaking of heavy oil with high metal and asphaltene content

The visbreaking of Canadian oil sands bitumen (OSB) and Tahe atmospheric residue (AR) with high metal and asphaltene content was studied to deepen the understanding of the utilization of ultra-inferior heavy oil. The total content of nickel and vanadium in the asphaltenes contained in Canadian OSB reaches 1300 ppm, promoting large-scale aggregation of asphaltenes. Driven by high asphaltene content of 19.3 wt% and large-scale aggregation of asphaltenes, Canadian OSB with an initial boiling point (IBP) of 500 °C exhibits rapid condensation during visbreaking. Furthermore, those asphaltenes with the highest metal content participate in condensation first, producing metallic nickel in the formed coke. By changing cutting strategy, the group composition and metal distribution of Canadian OSB can be adjusted. A viscosity reduction rate above 99 % is obtained during the visbreaking of Canadian OSB with an IBP of 350 °C, similar to the visbreaking of Tahe AR with an asphaltene content of 15.4 wt% and a total metal content of 300 ppm.

Structure-Solubility Relationship of CO Dispersion in Model Hydrocarbon Liquids and Heavy Oil Fractions.

The solubility of CO in heavy oils is an important parameter for designing and optimizing the partial upgrading process of heavy oil under CO/syngas and water. To study the structure–solubility relationship of CO dispersion in organic liquids, the solubility of CO in hydrocarbons (n-hexane, n-octane, n-hexadecane, cyclohexane, toluene, and 1-methylnaphthalene), petroleum distillates, and residues from Canadian oil sand bitumen was measured at different temperatures and pressures. The dispersion behavior of CO in different molecules was simulated by the molecular dynamics calculation. The role of water on CO dispersion in these systems was also explored. Experimental data show that the increase of both paraffinic chain length and aromaticity of molecules could hinder the dissolution of CO. By theoretical calculation, it is found that n-hexadecane and 1-methylnaphthalene present the strongest self-aggregation tendency, resulting in the low interaction with CO. The intermolecular forces of hydrocarbons appear to be the key factor determining the CO solubility. The dissolved H2O molecules could weaken the intermolecular forces of hydrocarbons and thus increase the CO solubility. Based on the model system study, the solubility of CO in complex petroleum distillates and heavy residues is rationalized by their molecular composition, which is mainly dependent on the relative proportion of paraffins to aromatics.

Fuel consumption analysis and cap and trade system evaluation for Canadian in situ oil sands extraction

A better understanding of fuel use and greenhouse gas (GHG) emissions resulting from Canadian oil sands (bitumen) extraction can help to meet the global carbon budget and design effective climate policies. To date, no studies have published actual fuel use data, analyzed drivers for the decline of emission intensities (EIs) from in situ oil sands extraction, and evaluated the effectiveness of the cap and trade system in Alberta that aims to control GHG emissions for the world's fourth largest oil production region. This study retrieved operating fuel use data from a public database for 18 in situ oil sands extraction schemes. From 2015 to 2019, the weighted average of fuel use was 0.23 103 m3/m3 undiluted bitumen. The weighted averages of fuel use for the schemes using Steam Assisted Gravity Drainage (SAGD) and Cyclic Steam Stimulation (CSS) were 0.20 103 m3 fuel/m3 of undiluted bitumen and 0.34 103 m3 fuel/m3 of undiluted bitumen, respectively. The average EIs for SAGD ranged from 0.25 metric ton (t) CO2e/m3 to 0.98 t CO2e/m3, and the average EIs for CSS ranged from 0.61 t CO2e/m3 to 1.18 t CO2e/m3. In addition, the study pointed out that production ramping up and maturity of reservoirs contributed to the decline in EIs. The study concluded that the current Alberta cap and trade system is not effective to control GHG emissions from in situ oil sands extraction. Some operations were rewarded for emission credits because of production increases, rather than actual emission reductions. An industry-wide benchmark (cap) should be considered to encourage competition. An absolute emission cap should be imposed to prevent facilities from simply increasing production to drive down EI values.

Determination of Carbonyl Functional Groups in Heavy Oil Using Infrared Spectroscopy

In this study, we examined carbonyl functional groups in Canadian oil sand bitumen using Fourier transform infrared spectroscopy (FTIR). FTIR spectra of a bromoform solution of the bitumen fraction...

Viscosity Mixing Rule and Viscosity–Temperature Relationship Estimation for Oil Sand Bitumen Vacuum Residue and Fractions

Removing heavy components through solvent separation is a potential routine for the viscosity reduction of Canadian oil sand bitumen. The mixing rule for the viscosity of extracted fraction is the basis of process simulation and optimization. In this study, supercritical fluid extraction fractionation was applied to separate Canadian oil sand bitumen vacuum residue (VR) into various fractions. The viscosity blending behavior of extracted fractions was experimentally evaluated. Several available viscosity mixing rules were tested. To predict the viscosity–temperature profile of derived fractions at different blending ratio, we proposed a new mixing rule based on empirical equation parameters. We also correlated the viscosity–temperature parameters to conventional bulk property, providing a method for the rapid viscosity estimation for VR, extracted fractions, and their mixtures.

Upgrading of Canadian Oil Sand Bitumen via Cracking and Coke Gasification: Effect of Catalyst and Operating Parameters

Canadian oil sand bitumen was stepwise converted via an integrated cracking and coke gasification (ICCG) process. The cracking behaviors of oil sand bitumen were investigated in a fluidized bed reactor with FCC and bifunctional (BFC) catalysts, respectively. The BFC catalyst specialized for the ICCG process was designed with both cracking and gasification activities. The results showed that the liquid yield of 78 wt % and conversion ratio of 87% of oil cracking could be simultaneously realized over hydrothermally treated catalysts (A-FCC and A-BFC) at 510 °C. The cracking performance of catalysts was closely related with their acidity, as indicated by NH3-TPD analysis. Coke deposit on the catalyst could lead to severe pore blockage. Catalyst regeneration via coke gasification could recover its pore structures and meanwhile produce high-quality syngas with the sum of H2 and CO up to 80 vol %. Comparing with FCC catalysts, the regeneration (coke gasification) time over BFC catalysts was shortened by about 3...

Transformation of Petroporphyrins-Enriched Subfractions from Atmospheric Residue during Noncatalytic Thermal Process under Hydrogen by Positive-Ion Electrospray Ionization FT-ICR Mass Spectrometry

Nickel and vanadyl porphyrins were separated from atmospheric residue of Canadian oil sand bitumen by solvent extraction and column chromatography and then subjected to noncatalytic thermal process under hydrogen. The petroporphyrins before and after thermal process were characterized by UV–vis spectroscopy and positive-ion electrospray ionization FT-ICR mass spectroscopy to probe their structural transformation. Three main vanadyl porphyrins, including N4VO, N4VOS, and N4VO2 and a fraction of N5VO2 are identified in the feed fraction. With time increasing, the relative abundance of CnH2n–28N4VO (DBE = 17) increases initially and then decreases, in contrast with CnH2n–26N4VO (DBE = 18). It suggests the hydrogenation and rapid hydrogenolysis of petroporphyrins. The carbon number shifts to the lower mass range with increased process severity, indicating extensive thermal cracking reactions of petroporphyrins have occurred. N4VOS porphyrins show very similar variation of DBE and carbon number distribution as N4VO. A considerable proportion of new types of N4VO2, N4VO3 and N5VO2 are identified in the product after 30 min by accurate mass measurement and isotopic distribution. Under more severe conditions, these new species gradually diminish. It is inferred that the new species could most possibly derive from disassociation of large molecules in addition to chemical transformation. H2S and high hydrogen pressure could promote the hydrogenation of petroporphyrins. H2S can also enhance their thermal cracking reaction while high hydrogen pressure inhibits it. Nickel porphyrins present almost the same phenomena with vanadyl porphyrins, though with low content. Analysis of the petroporphyrins at the molecular level reveals their behavior and transformation during thermal process under hydrogen and could also benefit the catalysts design in HDM process.

Review on catalysis related research at CanmetENERGY

AbstractCanada's oil sands and heavy oil represent a major North American energy source. However, many technological, economic, and environmental challenges must be overcome in order to improve the effectiveness and efficiency required for converting these unconventional oils into clean and high‐quality transportation fuels that meet the ever‐increasing social licence associated with these energy resources. In oil sands bitumen and heavy oil upgrading, and petroleum refining, over 70 % of the processes involve catalysts and catalytic technologies. To advance new catalysts and catalytic technology development for bitumen upgrading and refining, fundamental and applied research has been conducted at CanmetENERGY on hydroprocessing (including catalyst development, reaction mechanism and kinetics, and process/reactor modelling and simulation), fluid catalytic cracking evaluation of bitumen‐derived feedstocks, and other related subjects. In addition, research collaborations have been established and maintained with a number of national and international universities, research organizations, and industrial companies to promote new upgrading and refining technology development. These research efforts have resulted in important impacts on academic R&D and industrial practice for catalytic conversion of Canadian oil sands bitumen and heavy oil. At the same time, reliable technical data and information have been generated to help government agencies in developing and implementing policies and regulations for oil sands development.

Asphaltene Aggregation Behavior in Bromobenzene Determined By Small-angle X-ray Scattering

Small-angle X-ray scattering (SAXS) analyses of an asphaltene (a heptane-insoluble fraction in Canadian oil sand bitumen (CaAs)) at various concentrations in bromobenzene (BB) were performed at a synchrotron facility. BB is the first trial medium in which the aggregation behavior of asphaltenes has been elucidated, and is considered to be one of the “best” pure solvents for CaAs when determining the Hansen solubility parameters (HSP). Although the aggregation behavior of the CaAs in toluene (TL) and toluene–pentane mixed solvent (TL-PT10, containing 10% pentane on a volume basis) was confirmed to be similar to that reported in previous SAXS studies, the behavior in BB was markedly different. The results indicated that aggregates with a soft boundary of ∼30–60 A in the radius of gyration (Rg), which were observable in TL and TL-PT10, disappeared in BB and larger aggregates with a clear boundary appeared simultaneously. This phenomenon supported a colloidal aggregation model, with HSP analyses suggesting th...

Characterization of Vanadyl and Nickel Porphyrins Enriched from Heavy Residues by Positive-Ion Electrospray Ionization FT-ICR Mass Spectrometry

Petroporphyrins were enriched and purified from atmospheric residues of two typical heavy oils, Canadian oil sand bitumen (OSAR: Ni, 80 ppm; V, 190 ppm; S, 3.97 wt %) and Chinese Liaohe heavy oil (LHAR: Ni, 68.7 ppm; V, 1.81 ppm; S, 0.36 wt %) by silica-gel chromatography. The separation and purification were confirmed by atomic absorption spectroscopy (AAS) combined with UV–vis spectroscopy, and the petroporphyrins were characterized by positive-ion electrospray ionization (ESI) Fourier transform–ion cyclotron resonance mass spectrometry (FT-ICR MS). Vanadyl and nickel porphyrins in OSAR are simultaneously identified by mass measurement and isotopic fine structure. Vanadyl porphyrins with structures of N4VO, N4VO2, and N4VOS are all detected as protonated analyte ([M + H]+). Both molecular ion (M+•) and protonated analyte ([M + H]+) as well as their corresponding isotopes are observed for N4Ni porphyrins in OSAR and LHAR with an average mass resolving power of over 400000 (m/Δm50%). This is rarely detected by FT-ICR MS using ESI technique previously. Formation of molecular ion can be attributed to the low oxidation potential of nickel porphyrins, the effect of oil matrix on the solution conductivity, and the relatively low flow rate of solution into the capillary. Three more highly unsaturated types of N4VO porphyrins were identified in addition to the six well-documented structures. Compared to N4VO porphyrins, N4VOS porphyrins present higher DBE ranging from 21 to 27 while N4VO2 porphyrins show lower DBE ranging from 18 to 20 and narrower carbon number distribution, suggesting possible different origins of sulfur (pyrolysis of kerogen) and oxygen (diagenesis of chlorophyills). Ni/V and the ratio of relative abundance of ETIO porphyrins to DPEP porphyrins (∑ETIO/∑DPEP) for nickel porphyrins indicate that Liaohe oil and Canadian oil sand bitumen are continental and marine sediments, respectively, and Liaohe oil has a higher maturity. Enrichment by the simple chromatographic method facilitates the mass spectral identification of nickel porphyrins even for heavy residue with low content of nickel and high content of sulfur.

Mapping the Degree of Asphaltene Aggregation, Determined Using Rayleigh Scattering Measurements and Hansen Solubility Parameters

The degree of asphaltene aggregation (Dagg) over a wide range of concentrations in various solvents under ambient conditions was examined using a quantitative index derived from Rayleigh scattering measurements by ultraviolet–visible spectrometry and the Hansen solubility parameter (HSP). The source of asphaltene was Canadian oil sand bitumen. The target concentration was ≤10%, and the source of the solvent was organic solvents having Δδ ≤ 5.5 MPa0.5 of the HSP distance between each solvent and the asphaltene, such as toluene (TL), bromobenzene (BB), and toluene–pentane (TL–PT), toluene–bromobenzene (TL–BB), and toluene–quinoline (TL–QL) mixed solvents. Through these measurements, the effects of the concentration and solvent on Dagg were examined quantitatively, which enabled the mapping of Dagg. The Dagg map obtained facilitates estimation of Dagg under desired conditions, understanding of asphaltene aggregation behavior, and creation of a reasonable aggregation model.

Adsorption Kinetics of Nickel Etioporphyrin on VTB-Asphaltene in N-Pentane Solution

It is important to find out how to strengthen the interaction between nickel porphyrins and asphaltene in the alkane solvents of the low molecular weight for raising the removal rate of nickel in the solvent deasphalting process. Therefore, the adsorption kinetics, which describes how the nickel etioporphyrins are adsorbed on asphaltene (the vacuum residue of Canadian oil sands bitumen (VTB)) in the n-pentane solvent, are investigated. The results show that a certain amount of nickel porphyrins is absorbed on the asphaltene of VTB, which means there is a certain adsorption between asphaltene and nickel porphyrins. The adsorption rate is affected by the dosage of asphaltene, the concentration of the n-pentane solution containing nickel porphyrins and the temperature. A comparison in the four kinds of kinetic models on the overall adsorption rate shows that adsorption process can be perfectly described by the pseudo second-order equation.

Catalytic Cracking Reaction of Heavy Oil in the Presence of Cerium Oxide Nanoparticles in Supercritical Water

Catalytic cracking of Canadian oil sand bitumen in supercritical water was performed to clarify the effect of CeO2 nanoparticles. The cracking was performed at 723 K to promote a redox reaction between the water, bitumen, and catalyst for the production of hydrogen and oxygen. As the catalyst, CeO2 with two different morphologies was employed because the redox reaction of CeO2 with water and organics is expected and its activity can be controlled by its structure. In this study, two roles of water were considered as well. Water is attractive as a high potential medium with low dielectric constant and density at near the critical point (374 °C, 22.1 MPa) that allows formation of highly crystalline smaller metal oxides particles. However, the chemical effects of water are investigated with heavy oil catalytic cracking. Transmission electron microscopy images indicated that CeO2 nanoparticles with cubic and octahedral shape were synthesized using a plug-flow reactor under hydrothermal conditions. The particles sizes were 8 and 50 nm for cubic and octahedral CeO2, respectively. At 773 K, it was found that the oxygen storage capacity (OSC) of the cerium oxide nanoparticles with cubic {100} facets was nearly 3.4 times higher than that of the cerium oxide nanoparticles with octahedral {111} facets. Heavy oil fractions of bitumen were cracked in a batch-type reactor at 723 K in order to produce as much light oil as possible, and the effect of the catalyst loading and reaction conditions on the conversion rate and coke formation were investigated. As a result, it was demonstrated that it is possible to obtain a high conversion rate by increasing the exposed surface area and reducing the particle size of the catalyst. The highest conversion was obtained in the presence of 20 mg loading of cubic CeO2 nanoparticles (8 nm) with reaction time of 1 h.

Effects of experimental conditions on the molecular composition of maltenes and asphaltenes derived from oilsands bitumen: Characterized by negative-ion ESI FT-ICR MS

A vacuum topped Canadian oilsands bitumen (VTB) was subjected to solvent precipitation and subsequently characterized by elemental analysis, gel permeation chromatograph (GPC), 1H-NMR spectroscopy and negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Effects of experimental conditions such as solvent types (n-C5, n-C6, and n-C7), solvent purity, and solvent washing time on asphaltenes yields, bulk composition, and molecular composition of detectable heteroatom compounds in ESI source were determined. Elemental nitrogen and sulfur were enriched in asphaltenes while elemental oxygen had comparable content in maltenes and asphaltenes. Molecular composition of asphaltenes varies with separation conditions. The N1 and O1 species identified by ESI FT-ICR MS were enriched in maltenes. The O2 species exhibited two different double bond equivalents (DBE) distributions and solubility in normal paraffin solvents, indicating two types of molecular structures. Multi oxygen atom containing compounds mainly detected in asphaltenes. Compound class distributions are similar for maltenes derived from n-C5, n-C6, and n-C7, as well as for asphaltenes. The cyclic paraffin impurities in normal paraffin solvents had a significant influence on asphaltenes yields and heteroatom molecular composition. A portion of neutral N1 species and acidic O2 species adsorbed on asphaltenes could be dissolved by increasing washing time. Cautions should be exercised when interpreting the properties and composition of asphaltenes obtained with different experimental conditions.

Production of Light Oil by Oxidative Cracking of Oil Sand Bitumen Using Iron Oxide Catalysts in a Steam Atmosphere

Catalytic cracking of Canadian oil sand bitumen was performed using zirconia−alumina−iron oxide catalysts at 450−500 °C in a steam atmosphere. The heavy-oil fraction of bitumen was oxidatively cracked to produce light oil, corresponding to gasoline, kerosene, and gas oil, with a boiling point of <350 °C. However, some coke was generated after the reaction of bitumen, whereas coke was not generated from conventional residual oil at the same reaction conditions. To suppress the coke generation, reaction conditions were changed on the basis of the reaction mechanism. When the time factor (ratio of the catalyst weight/feedstock flow rate) increased, large amounts of active oxygen species were generated from steam and these species suppressed the coke formation. The largest yield of light oil was approximately 50 mol % C with no coke formation for reaction conditions of a time factor of 3.6 h at 450−500 °C and 2.0 h at 500 °C.

Effect of supercritical water on upgrading reaction of oil sand bitumen

The advantages of supercritical water (SCW) as a reaction medium for upgrading oil sand bitumen were investigated through a comprehensive analysis of the output product, which includes gaseous products, middle distillate, distillation residue, and coke. Canadian oil sand bitumen mined by the steam assisted gravity drainage method was treated in an autoclave at 420–450 °C and 20–30 MPa for up to 120 min with three kinds of reaction media: SCW, high-pressure nitrogen, and supercritical toluene. The yields of gaseous products indicated that a very small amount of water was involved in the upgrading reaction. The analytical results of the middle distillate fractions were almost the same using water and nitrogen at 450 °C. The distillation residues produced in SCW had lower molecular weight distributions, lower H/C atomic ratios, higher aromaticities, and consequently more condensed structures compared to those produced in nitrogen. The coke produced using SCW also had lower H/C values and higher aromaticities. Judging from all the analytical results, the upgrading of bitumen by SCW reaction was primarily considered to be physical in nature. As a result, it is possible to highly disperse the heavy fractions by SCW. This dispersion effect of SCW led to intramolecular dehydrogenation of the heavier component and prevention of recombination reactions, and consequently gave the highest conversion.

Characterization of Sulfur Compounds in Oilsands Bitumen by Methylation Followed by Positive-Ion Electrospray Ionization and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Sulfur compounds in Canadian oilsands bitumen were reacted with methyl iodide in the presence of silver tetrafluoroborate and converted to methylsulfonium salts. The methylsulfonium salts were characterized by positive-ion electrospray ionization (ESI) and Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS). Heteroatoms were characterized by their class (number of nitrogen, oxygen, and sulfur heteroatoms), type [rings plus double bonds (DBE)], and carbon number distribution. The S1, S2, S3, O1S1, O1S2, O2S1, and N1S1 sulfur-containing class species were identified in bitumen-derived methylsulfonium salts. The molecular weights of the sulfur compounds were varied from 200 to 700 Da. The Sx class species were the predominant heteroatom compounds. The S1, S2, and S3 class species comprised 74%, 11%, and 1%, respectively, of the total identified species. As the sulfur atom number increased, the DBE of the abundant Sx class species shifted to a higher value. Sulfur species identified from...

Catalytic Pyrolysis of Gas Oil Derived from Canadian Oil Sands Bitumen

The catalytic pyrolysis behaviors of gas oil derived from Canadian oil sands bitumen over catalyst CEP-1 in a confined fluidized bed reactor have been investigated in the present paper. The effect of reaction temperature, catalyst-to-oil weight ratio, steam-to-oil weight ratio, and residence time of oil gas on product distribution was researched. The results show that the optimal reaction temperature, weight ratios of catalyst to oil and steam to oil, and residence time of oil gas are about 660 °C, 15, 0.55, and 2 s, respectively. Under the optimal operating conditions, the yield of total light olefins exceeds 38.0 wt %. A new five-lump kinetic model is developed for the catalytic pyrolysis of gas oil, and a catalyst deactivation model based on the coke content is also presented. Rate constants and apparent activation energies were estimated with the least-squares method. The effect test shows that the five-lump kinetic model can predict the yields of gasoline, light olefins, light alkanes, and coke very ...