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This paper is in honor of Michael (Mike) T. Klein, and his contributions to the modeling of thermal conversion are highlighted within the context of this study. The question that was posed is wheth...

The catalytic cracking of visbreaker naphtha under industrial conditions has been investigated, aiming the production of an olefin-rich gas stream and high-quality gasoline suitable to be used in t...

Thermal conversion of bitumen by visbreaking is an important technology for partial upgrading of bitumen to pipeline transportable oil. The product from visbreaking of bitumen will likely spend a l...

In this study, the effect of gamma alumina-based molybdenum oxide nanoparticles, on the viscosity reduction of extra-heavy crude oil in a catalytic cracking process in atmospheric pressure and at 250–350 °C investigated for the first time. Molybdenum oxide nanoparticles synthesized using the polyol method and heating by microwave radiation. According to the dynamic light scattering (DLS) analysis, obtained nanoparticles have an average size of 6 nm. These nanoparticles coated on gamma-alumina powder using the novel method of per-vaporation, and through this method, 0.011 g of molybdenum oxide nanoparticles coated over per 1 g of catalyst, during 14 days. The performance of the synthesized catalysts in the cracking process of extra-heavy crude oil investigated. Statistical design of the experiment (DOE) used to study the effect of catalyst concentration and process temperature on product viscosity and to obtain optimal value of these factors. Based on the central composite design (CCD) method, the cubic model developed to correlate the catalyst wt% and temperature for upgraded oil viscosity. By applying the synthesized nanocatalyst in the range of 0.59–4 wt%, the viscosity reduction from 32 to 86% was observed. The highest viscosity reduction happened at 350 °C and 2% weight percent of nanocatalysts, in which the viscosity reduced from 20,000 cp to 2800 cp.

The formation of new heavier material during thermal processing has long been known, and under typical visbreaking conditions, vacuum conversion of deasphalted oil is described using a first-order ...

The inlet temperature of the Vacuum Gas Oil (VGO) hydrotreating reactor of a refinery is analyzed with the integration of multiple series reactors and hydrogen network considered. The effect of the inlet temperature (T1) on hydrogen sinks/sources and the product output is analyzed systematically based on the simulation of the series reactors, including VGO hydrotreating reactor, hydrocracking reactor, fluid catalytic cracking reactor and visbreaking reactor. The general relation between the Hydrogen Utility Adjustment (HUA) and multiple pairs of varying sinks and sources is deduced, and correlations between varying streams and T1 are linearly fitted. Based on this, the quantitative equation between HUA and T1 is derived, and corresponding diagram is constructed. The T1 corresponding the minimum hydrogen consumption is identified to be 345 °C.

The review deals with extraction refining of straight-run diesel fractions, atmospheric gasoil, gasoils from secondary oil refining processes (decelerated coking, visbreaking, catalytic cracking), and light and heavy vacuum gasoils to remove heteroatomic sulfur- and nitrogen-containing compounds, polycyclic arenes, and resins using selective organic solvents and extraction systems with a nonpolar solvent. Possible methods for extraction regeneration and extract application fields are considered.

The description of the stability index of the residue marine fuels, whose technology of production is based on the compounding visbreaking residue, light cycle gas oil, and ultralow sulfur diesel b...

The present study aims at investigating the evolution of the rheological properties of a primary bitumen with ageing (first service life), hot recycling (50/50 blending of virgin and aged bitumen, ...

The visbreaking of heavy oil in supercritical benzene (SCbenzene) was investigated. By introducing SCbenzene, the visbreaking originally occurring in the oil phase is transferred into SCbenzene. The superior diffusivity in SCbenzene improves the efficiencies of the initiation and propagation of visbreaking network, by which the reaction could be run in the desired tandem structure. By mitigating diffusion limitation to reaction kinetics, the cracking of alkyl substitutes of aromatics vital to viscosity reduction is accelerated. Being the secondary reaction of the cracking, condensation could be terminated promptly at the shortened reaction time necessary for visbreaking. A comparison between the visbreaking in SCbenzene and supercritical water (SCH2O) confirms the effectiveness of improving diffusion for the optimization on heavy oil visbreaking. Nevertheless, the optimal operating conditions involved must be determined experimentally because of the complicated interaction between phase structure and reac...

The time-dependent thermal conversion of vacuum residue deasphalted oil was studied at 280, 320, 360, and 400 °C. The vacuum residue deasphalted oil was an industrial product produced by vacuum distillation of Athabasca bitumen followed by solvent deasphalting using n-pentane. This type of visbreaking process was of interest for partial upgrading of bitumen to facilitate pipeline transport. Practically useful cracking conversion and viscosity reduction for upgrading were found only at 360 and 400 °C. The viscosity measured at 40 °C could be reduced by 3 orders of magnitude from 3720 Pa s in the feed to 2–5 Pa s in the product. The density of the product was not reduced by much, despite vacuum residue cracking conversions of 34% at 360 °C and 45–47% at 400 °C before the onset of coking. The liquid yield was 88–89%. A heavier product fraction was formed during thermal conversion. The heavy material was not necessarily asphaltenes, but an increase in n-pentane-insoluble material was also found that appeared ...

Tube furnaces are equipment widely used in many processes, especially in the oil and gas, petrochemical, and oil refining industries. The most vulnerable furnace element is the coil, in which coke and other compounds are deposited and ultimately lead to its burnout and an emergency. The coil technical condition is mandatorily checked by non-destructive testing during scheduled preventive maintenance but is not controlled during the TBR period. The paper proposes a system for automated diagnostics of internal deposits in the visbreaking tube furnace coil. The real-time coil condition diagnostics is performed by ten criteria. These criteria include the main process parameters of the furnace and auxiliary criteria as ratios of certain values, e.g., the ratio of the fuel gas flow rate to the coil wall temperature in the heating section. For each of these criteria, mathematical models have been built and the values corresponding to the normal and abnormal modes rated based on statistical data. The diagnostics algorithm proposed allows determining the normal coil operating mode, the loss of communication with the measuring instruments, and the process mode violation with localizing a specific section.

In this article existing approaches to intensify the visbreaking process are considered and the imperfections in the proposed schemes are analyzed. As a result, the study has been concluded to identify a methodology for the visbreaking process that covers all these aspects. The analysis has revealed the most vulnerable parts of the system and it has developed the corrective actions to minimize the risks identified. The research proposes to complete the technological scheme with an air-preheat unit, a flash tower and thermogravimetric analysis sensors, and to use by-products as fuel for the unit. In support of the research, economic calculation results have been obtained, that proved the efficiency of the investment project.

Bitumen extracted from Canada’s oil sands resources is an abundant, unconventional crude oil used to produce liquid fuels. To permit its transportation by transmission pipelines from production sites to upgraders and refineries, the highly-viscous bitumen must first be blended with up to 50 vol% of light oil (“diluent”) to produce a diluted bitumen (DB) with sufficiently low viscosity and density. Diluents occupy substantial pipeline capacity, and are relatively expensive, so Canada is developing “partial upgrading” processes to reduce the diluent content of pipeline-transportable bitumen products. Such processes lower bitumen’s density and viscosity by removing some portion of its heaviest, asphaltene-rich fraction by, for instance, solvent-induced separation and/or thermochemical conversion. Thus, processed bitumen products (PBPs) require less diluent to meet specifications for transmission pipeline transportation. We compare the minimum diluent content requirements of several PBPs meeting such specifications for density (≤ 940 kg/m3 at 15.0 °C) and viscosity (≤ 350 cSt at a pipeline temperature of 10.6 °C, selected on the basis of DB viscosity measurements). In this work, PBPs meeting pipeline transportation specifications are prepared by visbreaking and/or solvent-deasphalting of bitumen followed by dilution with 32–47 wt% less diluent than the corresponding unprocessed DB. Public concern about environmental risks associated with spillage of emerging PBPs during transportation has spurred investigations of these products’ interactions with water. With little currently known about their aquatic behaviours, we evaluate the emulsification and dispersion tendencies of pipeline-transportable PBPs after mixing these with fresh water following a reported protocol, and compare these results with those for DB, bitumen-derived synthetic crude (SC) oil, and conventional crude (CC) oil. The characteristics of floating water-in-oil emulsions are shown to depend upon the oil’s asphaltene content and thermochemical process history. At high mixing energy, dispersed oil content within the water column is seen to increase with oil resin-to-asphaltene ratio. In the aquatic system employed, oil content of the water column is greatest for SC, followed by solvent-deasphalted products and DB, followed by only-vis-broken product and CC. These results may aid in the development of oil spill behaviour models and response plans needed for transporting PBPs.

The results of the calculation of the reactivity descriptors of structurally different polyaromatic hydrocarbons (PAHs), which act as starting compounds in condensation and polymerization reactions and the subsequent formation of coke occurring on the heating of hydrocarbon raw materials in the course of visbreaking in tube furnaces are presented. The activation energies and preexponential factors of chemical reactions of hydrogen atom removal from PAH molecules, which simulate the local environment of a coke layer, as a result of their interaction with the radical ⋅CH3 were calculated using quantum chemical methods.

Performance predictions of the In-Situ Combustion (ISC) process is a challenge as it involves complicated chemical reactions, fluids movement, phase changes, and heat and mass transfer. This study investigates how oil type and water presence can affect the ISC performance, based on using a combination of combustion tube and Thermogravimetric Analysis and Differential Scanning Calorimetry (TGA/DSC) experiments. Combustion tube experiments were conducted with two different crude oil without water (Swi = 0%) and with the presence of water (Swi = 34%). Experimental conditions were kept constant (3 L/min air injection rate and 100 psig pack pressure) for all four experiments conducted with two different oil samples. To determine the chemical reactions that occurred during combustion tube experiments, the initial crude oil samples and their Saturates, Aromatics, Resins, and Asphaltenes (SARA) fractions were subjected to TGA/DSC experiments under air injection at two constant heating rates with and without water addition. Because two heating rates were observed during combustion tube experiments, 5 °C/min was used to represent the slow heating region (Steam Plateau, Evaporation and Visbreaking) and 20 °C/min was used to mimic the rapid heating region (Cracking Region and Combustion Zone). To better understand the complicated mutual interactions of functional groups in crude oil, TGA/DSC experiments were repeated on normal-decane (an alkane), decanal (an aldehyde), decanone (a ketone), and decanol (an alcohol) which represent the low temperature oxidation (LTO) products. Note that these chemicals have a constant carbon number (C10). The combustion tube experiments showed that Oil 1 was able to burn for both conditions (with and without water), while Oil 2 could only sustain combustion with water. To determine the reason for this difference, the burning behavior of the crude oils and their individual SARA fractions with and without water additions was studied through TGA/DSC experiments. At the high heating rate (20 °C/min), heat generation does not vary for both crude oil samples. However, at the low heating rate (5 °C/min), Oil 1 generates a higher amount of energy at high temperature oxidation (HTO) zone. We observed similarities between the decanone (a ketone) burning behaviors with aromatics fractions for Oil 1 which indicates that the aromatics fraction may contain ketone functional groups as LTO products. Upon burning, ketones generate higher energy than any LTO products. Therefore, Oil 1 may have functional groups in its structure more like ketones which promotes its combustion more than Oil 2. While presence of water does not change the burning behavior of Oil 1, we observed that the aromatics fraction of Oil 2 in the presence of water generates components similar to decanol (an alcohol) burning behavior. Note that alcohols generate more heat than aldehydes upon burning which explains the enhancement of Oil 2 burning behavior in the presence of water. However, aldehydes produced less energy than ketones. As a result, the combustion performance of Oil 2 was poorer than Oil 1. These results suggest that the chemical structure of the aromatics fraction is critical for the success of ISC. Water and aromatics fraction interaction at elevated temperature favors ISC reactions.

This paper presents an optimization model of inspection and replacement planning for a refinery plant under the consideration of corrosion in terms of cost. The management of corrosion is an essential task for processes that operate over several years without a shutdown. This is because corrosion can cause severe failures by thinning the wall thickness and eventually cause pipes or equipment to burst. However, required safety measures, such as the corrosion management, involve costly inspection and replacement. Therefore, a cost-effective safety-action strategy is proposed in this paper. The developed model presents an optimal combination of steel grade, design wall thickness, inspection number, and inspection timing under a given corrosion rate to minimize the cost of design, inspection, replacement, and failure. Three case studies using sensitivity analyses are applied to three major processes in a refinery plant: a crude distillation unit, visbreaker, and hydrocracker.

In view of the worsening quality of crude oil, the use of unconventional petroleum feedstocks (heavy oils, bitumens, residues, etc.) in processing is becoming increasingly important. The processing of heavy oil feedstocks (HOF) requires the development of new effective techniques that will lead to an increase in the yield of light fractions, suppression of coke formation, and saturation of liquid products with hydrogen. At the same time, the capital and operating costs of the process should be minimized because the cost of production and transportation for HOF is several times higher than for light and middle oils. The present review summarizes the results of studies of the catalytic steam cracking of HOF—a potential alternative to conventional HOF upgrading based on carbon rejection (thermal cracking, visbreaking, catalytic cracking) or hydrogen addition (hydrocracking). The main differences of this process from HOF upgrading with water (aqueous pyrolysis in sub- or supercritical water), the peculiarities of the catalytic steam cracking depending on the process conditions and the type of catalyst, and possible mechanisms of water participation in the process were discussed.

Initiator is used in the aquathermolysis visbreaking of heavy oil combined with catalyst and other additives. The results show that viscosity reduction ratio goes up from 61.4% to 72.7% after adding 0.2 wt% di-tert-butyl peroxide at 220°C. Initiator is an effective addictive and can further enhance the level of thermal cracking, surprisingly leading to a decent viscosity reduction ratio 69.0% under a relatively low reaction temperature of 150°C. Oil samples are analyzed before and after the reaction, with results showing that the contents of saturate and aromatic increased, while the contents of resin and asphaltene decreased. In addition, the average molecular weight value of each component decreased after the reaction. Elemental analysis of both resin and asphaltene shows that hydrogen to carbon atomic ratio increases slightly. The contents of sulfur decreased remarkably, yet the contents of nitrogen decreased slightly. This phenomenon indicates that sulfur plays a remarkably important role during the aquathermolysis. The HAU/CA of both resin and asphaltene increases. The results above imply that with the help of catalyst and hot water, the cracking reaction of heavy oil occurs, and initiator strengthens the process. Asphaltene and resin suffer a deeper level of cracking into lighter fractions, leading to a substantial viscosity reduction and then an improvement of the flow properties of heavy oil, which also contributes to the improvement of the quality of heavy oil.

The visbreaking of heavy oil under high-pressure N2 or supercritical water (SCW) environment was experimentally investigated. Despite the difference in the reaction media, the visbreaking follows the same mechanism, that is, dealkylation and condensation of aromatics. The presence of SCW makes it possible that the visbreaking of heavy oil is transferred to the SCW phase with superior diffusivity by which the visbreaking tends to be controlled by intrinsic reaction kinetics rather than by diffusion. Accordingly, dealkylation occurring in the SCW phase, which is vital to the viscosity reduction of heavy oil, responds sensitively to the increase in reaction temperature. Being the secondary reaction of dealkylation at moderate temperatures, condensation is effectively suppressed with reduced reaction time required for dealkylation. By the introduction of SCW and the adoption of an appropriate reaction temperature, the visbreaking efficiency could be drastically improved together with guaranteed stability of v...

Determination of stability of high-viscosity marine fuel from the point of colloid chemistry concept of oil disperse systems and the need for inclusion of this parameter in the current requirements are expounded. High-viscosity marine fuels produced from residual fuel oil, visbreaking residue, and catcracking light gas oil were taken as the objects of the study. The stability of the obtained samples was determined via xylene equivalent. Also determined was the effect of dispersing additives based on hydroxyethylated amines and alkyl naphthalenes on the stability of the obtained samples of high-viscosity marine fuels.

Deterioration of the quality of oilstock makes it an urgent problem to use non-traditional hydrocarbon materials (heavy oil, bitumen, residues etc.). Processing of heavy oilstock (HOS) needs new methods that would be effective for the yields of light fractions, suppression of coke formation, and saturation of the liquid products with hydrogen. At the same time, expenses of HOS extraction and transportation are several times as high as those of light and middle oils that makes it necessary to minimize the capital and operational costs for the process. The review paper integrates for the first time the results of the studies of catalytic steam reforming of HOS as a potential alternative of the traditional processes for HOS upgrading based on decreasing the carbon content (thermal cracking, visbreaking, catalytic cracking) or on the saturation of liquid products with hydrogen (hydrocracking). Under discussion are main distinctions of the process from HOS upgrading with water (hydropyrolysis in sub- or supercritical water) as well as specific features of the catalytic steam cracking as dependent on the process parameters and catalysttype and putative mechanisms of the participation of water in the process.

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.

To understand the reaction behavior of heavy oil visbreaking with reduced diffusion limitation, the visbreaking of an atmospheric residual oil in the solvent of supercritical benzene (SCbenzene) was applied, followed by a reaction kinetics analysis based on a hybrid lumping with combination of boiling point distribution and group composition of oil components. The visbreaking under SCbenzene environment was found to be much faster than that under nitrogen environment, proceeding effectively even at a temperature lower to 350 °C. Although the dealkylation-based lumped reactions responsible for light component production and viscosity reduction are supposed to dominate the visbreaking, a competition between dealkylation and condensation exists throughout the visbreaking. Because of the reduced diffusion limitation to reaction kinetics, the condensation-based lumped reactions with a higher activation energy up to 306 kJ.mol−1 respond more sensitively to the variation of reaction temperature, greatly shortening the reaction time window for the visbreaking at high temperatures.

This work presents characterization data and viscosity of 34 secondary vacuum gas oils (H-Oil gas oils, visbreaker gas oils, and fluid catalytic cracking slurry oils) with aromatic content reaching up to 100 wt.%. Inter-criteria analysis was employed to define the secondary VGO characteristic parameters which have an effect on viscosity. Seven published empirical models to predict viscosity of the secondary vacuum gas oils were examined for their prediction ability. The empirical model of Aboul-Seud and Moharam was found to have the lowest error of prediction. A modification of Aboul-Seoud and Moharam model by separating the power terms accounting for the effects of specific gravity and average boiling point improves the accuracy of viscosity prediction. It was discovered that the relation of slope of viscosity decrease with temperature enhancement for the secondary vacuum gas oil is not a constant. This slope increases with the average boiling point and the specific gravity augmentation, a fact that has not been discussed before.

Today science and engineering are concerned with maximising profit while maintaining minimum air emissions from chemical plants such as oil refineries. Air emissions, such as NO2, when exists in large amounts, it could cause different types of serious diseases and illnesses. This research focuses on studying NO2 emissions from oil refineries while maintaining a maximum profit and the desired final products quality such as sulphur contents in fuel or octane number for gasoline. This paper aims to analyse the cost-profit of an oil refinery with the inclusion of Visbreaker unit. Visbreaker unit contribution to the revenue of oil refinery was not included in previous literature. The Economic power of Visbreaking unit in an oil refinery is given a good chance, for the first time in research work; to be evaluated economically and show its strength and money return to the plant with other product and NO2 constraints. The objectives of visbreaking are to reduce the viscosity of the feed stream, reduce the amount of residual fuel oil produced by a refinery and increase the proportion of middle distillates in the refinery output. In addition, the aim of the study is to find how to reduce NO2 emissions from oil refineries using different technologies while maintaining profit at maximum possible level using mathematical modeling approach. The three methods being used for NO2 reduction are; balancing, fuel switching and use of technology for NO2 reduction. NO2 emissions will be reduced by using the above three methods to reach different reduction percentage ranging from 20% to 80%. The profit of the oil refinery for each reduction target of NO2 was analysed and looked at closely. For example, at the 20% of NO2 reduction target, profits were $720 million. At the 80% reduction target, profits dropped down to $701 million. The contribution of Visbreaker to final products was calculated. For example, Visbreaker was responsible for adding 60,000 bbl of light and heavy naphtha to final products with total sales of around $6.0 million per year for this contribution. The model is mixed integer nonlinear (MINLP) and GAMS package is used to run a case study to validate the developed model. In addition to maximising profits, maintaining good quality products, reducing NO2 emissions and focus on Visbreaker products contributions is investigated deeply.

The yields of gasoline, light and vacuum gas oils, and gas fraction in thermal cracking of heavy oil residues (visbreaking) were mathematically modeled. Calculation formulas with high statistical characteristics were obtained.

Solvent deasphalting and visbreaking are two important technologies in the development of processes for partial upgrading of oilsands-derived bitumen to improve oil fluidity for pipeline transport. This work investigated the impact of the process sequence, solvent deasphalting followed by visbreaking (SDA-Vis) compared to visbreaking followed by solvent deasphalting (Vis-SDA). Thermal conversion during visbreaking was performed at 380 °C for 85 min, and solvent deasphalting was performed with n-pentane. Using this combination of processes in either sequence changed bitumen from a viscosity-limited fluid to a density-limited fluid with respect to pipeline specifications. The density and viscosity of the oil products from SDA-Vis and Vis-SDA were comparable. It was found that SDA-Vis achieved 2 wt % higher liquid yield than Vis-SDA. Conversely, Vis-SDA produced an oil product with higher hydrogen to carbon ratio compared to SDA-Vis. This difference could be explained in terms of hydrogen transfer during the...

The interaction of hydrogen peroxide aqueous solutions with crude oil and high-boiling refined products, such as fuel oil and vacuum gas oil, in the presence of an oxidative cracking catalyst in the form of iron oxide nanosized particles is studied. This study is aimed at modeling processes occurring in the case of using hydrogen peroxide solutions in the catalytic cracking of crude oil. It is found that, in the presence of iron particles, the reaction of hydrogen peroxide decomposition causes the cracking of petroleum hydrocarbons. This process may be accompanied by reduction in the viscosity and density of crude oil and refined products. The reaction of catalytic cracking performed under these conditions leads to a marked increase in the fraction of light hydrocarbons in the composition of crude oil and high-boiling refined products.

The process of the atmospheric-oxygen-induced cracking of heavy oils of various nature and compositions in a continuous flow reactor has been studied. The process variables for conversion of heavy oils into gasoline and diesel fractions have been determined that ensure the maximum yield of the above fractions with simultaneous production of marketable heavy residues. The developed technology can be applied in industry upon minor upgrading of the operating thermal cracking or visbreaking units. This upgrade will result in a considerable increase in the oil refining depth.

This study evaluates the economic viability of various post-production upgrading techniques for heavy oil. Heavy oils represent 60% of overall crude oil resources, worldwide. However, there are challenges associated with all phases of operation chain owing to high viscosity and low API. In this study, we present a comparative study of five post-production processing techniques in terms of their recovery factors, and economics. We use five different techniques to study post-production processing of heavy oil: 1) dilution with lighter crude, 2) partial upgrading via visbreaking, and 3) wellsite mini-refinery with three various configurations. Two heavy oil samples are selected based on API gravity and sulfur content. Simulations have been conducted to study various processes for the chosen oil samples. Key parameters controlling each technique have been identified and impact of each parameter have been analyzed with sensitivity studies. Advantages and disadvantages of each process are compared to assess the performance at different operational conditions, including oil price. Results indicate an overall net margin of $1 per barrel for blending, between $7 to $9 per barrel for partial upgrading technique, and between $13 and $20 per barrel for mini-refinery. Moreover, when production rate or the crude price is low, blending yields the best performance as it requires the lowest capital cost. Mini-refinery becomes profitable when production exceeds 20,000 barrel per day or oil price surpasses $ 50 per barrel. In addition, for dilution process operation cost has the largest impact on NPV calculations whereas interest rate and capital cost are most dominant factors for visbreaking and mini-refinery techniques. The main contribution of this work is an economical comparison of different post-production heavy oil processing technologies to identify the optimal process under different conditions.

The quality and properties of asphalt binders are one of the most important factors that affect lifetime of asphalt roads. In refineries, visbreaking residues (VFCRs) are sometimes added to asphalt binders in variable ratios. VFCR addition can affect the overall properties of the manufactured binder, in particular resistance against aging. Using selected laboratory tests, this paper analyzes the effects of adding VFCRs to paving bitumens with a gradation of 160/220 on its properties (needle penetration, softening point, complex shear modulus and phase angle and creep stiffness and m-values). Also the effect of simulated aging of binders containing VFCRs on their properties has been tested. It was found that by increasing the VFCR content and the extent of aging, the binder stiffness increases. At higher VFCR ratios, the binder is more affected by aging at higher temperatures. Increased amount of VFCR also negatively affects low-temperature properties of the binder, which is related to its higher stiffness.

Thermal cracking processes such as visbreaking are used in the petroleum industry to reduce the viscosity of heavy feedstocks, such as atmospheric and vacuum residues, without forming coke or unstable asphaltenes. Thermal cracking offers a potential method to reduce the viscosity of heavy oils and bitumen, enabling their pipeline transportation with less solvent addition. Viscosity is the most important property for transportation of crude oils, but this property also has a highly non-linear dependence on temperature and composition. In this work, we used a lumped-kinetic model, based on boiling point pseudo-components, coupled with a fluid property model, to correlate the viscosity of two heavy oils subjected to thermal cracking reactions at different severities, and assess the impact of the chemical transformations on the behavior of the heaviest fraction. The properties of these pseudo-components were estimated by validated correlations, and tuned with experimental values. By assuming that after the reactions these properties remained invariable in each boiling point pseudo-component, we could estimate the viscosity of the liquid products from the recombination of these individual properties using mixing rules available in literature. The results indicated that the vacuum residue fractions (>524 °C) undergo chemical transformations that alter their fluid properties. By using adjusting factors dependant on conversion, we were able to make estimations of viscosities at different temperatures with absolute average deviations lower than 25%.

Some bituminous binders currently available on the Central European market contain a certain ratio of visbreaking residues, obtained during non-catalytic thermal cracking of atmospheric or vacuum crude oil residues. This paper deals with a potential presence of visbreaking residues in commercially available paving grade bitumens, and their impact on the thermooxidative properties of the bitumen. The presence of visbreaking residues can be possibly indicated by the compromised chemical compatibility of the bituminous binder that can be determined by Heithaus titration. However, Heithaus titration is a relatively complicated process. It is therefore sufficient to use a simplified alternative in practice – single-point precipitation titration using isooctane. All of the tested bitumens were submitted to the accelerated ageing procedure. The changes in parameters caused by the ageing process were determined by means of a dynamic shear rheometer and bending beam rheometer. The obtained data were subsequently c...

Catalytic steam cracking (CSC) of heavy hydrocarbons is seen as an alternative for further improvement upon conventional thermal cracking performance. In this work, upgrading of an industrial deasphalted vacuum residue via CSC was assessed in a bench-scale pilot plant resembling a visbreaking unit. The performance of a 400 ppm of Ni and 300 ppm K ultradispersed catalyst (UDC) formulation previously used for CSC of vacuum residue was evaluated for this nonasphaltene containing fraction. Reactivity experiments were conducted at temperatures within 435–445 °C and liquid hourly space velocities (LHSV) of 3–5.5 h–1 and operating pressure of 300 psig. A preliminary reactivity evaluation using isotopic water spanning temperatures between 423 and 445 °C was carried out to determine the conditions at which water splitting was occurring. Finally, lumped kinetic modeling including asphaltenes generation in the process was evaluated, and results were compared with previously reported thermal cracking experiments. Ope...

A data-mining and Bayesian learning approach is used to model the reaction network of a low-temperature (150–400 °C) visbreaking process for field upgrading of oil sands bitumen. Obtaining mechanistic and kinetic descriptions for the chemistry involved in this process is a significant challenge because of the compositional complexity of bitumen and the associated analytical challenges. Lumped models based on a preconceived reaction network might be unsatisfactory in describing the key conversion steps of the actual process. Fourier transform infrared spectra of products produced at different operating conditions (temperature and time of processing) of the visbreaking process were collected. Bayesian agglomerative hierarchical cluster analysis was employed to obtain groups of pseudospecies with similar spectroscopic properties. Then, a Bayesian structure-learning algorithm was used to develop the corresponding reaction network. The final reaction network model was compared to the anticipated reaction netwo...

Refineries process a number of gas oils such as straight run gas oil (SRGO), light cycle gas oil, coker gas oil and visbreaker gas oil for producing a common gas oil pool to be used as a transportation fuel. Considering stringent sulfur standards, new strategies and design modifications are being evaluated for desulfurization of these gas oils with minimum loss of oil during the desulfurization process. In this review, developments in solvent extractive desulfurization of gas oil have been discussed from both fundamental and applied point of views. Various performance indicators used for solvent evaluation/screening in computational and experimental studies are discussed. Particular emphasis has been given on latest developments in performance evaluation of organic and ionic liquid solvents for desulfurization of SRGO and other gas oils. Various possible designs of solvent recovery section to remove solvent from raffinate and extract phases for solvent recycling have been reviewed. Various potential optio...

In this short communication, vacuum residue, bitumen, and pyrolized fuel oil were analyzed using matrix-assisted laser desorption/ionization – time of flight (MALDI-TOF) analysis to investigate the molecular weight distribution (MWD) variation of heavy oil during visbreaking. The visbreaking of vacuum residue was carried out at 350 °C, 400 °C and 450 °C. Vacuum residue products were studied based on MWD obtained by MALDI-TOF analysis. The separation of MWD was carried out in 8 sections, and each area of the range was calculated. According to our study, the cracking reaction dominated, even though condensation and polymerization were carried out simultaneously. It was noted that the relatively high molecular ranges of 3 and 4 were shifted to the light molecular range of 2. The MWD separation method obtained by MALDI-TOF is a potential analytical tool for investigating the MWD variation of heavy oil.

Fracturing wastewater is often highly emulsified, viscous, and has a high chemical oxygen demand (COD), which makes it difficult to treat and recycle. Ferrate(VI) is a green oxidant that has a high redox potential and has been adopted for the efficient oxidation of fracturing wastewater to achieve triple effects: demulsification, visbreaking, and COD removal. Firstly, optimal conditions were identified to build a model for fast and efficient treatment. Secondly, wastewater treatment using ferrate oxidation was investigated via demulsification, visbreaking, and COD removal. Finally, a mechanism for ferrate oxidation was proposed for the three effects using Fourier-transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The theoretical and experimental data demonstrated that the ferrate oxidation achieved the three desired effects. When ferrate was added, the demulsification efficiency increased from 56.2% to 91.8%, the total viscosity dropped from 1.45 cp to 1.10 cp, and the total removal rate of COD significantly increased to 74.2%. A mechanistic analysis showed that the strongly-oxidizing ferrate easily and efficiently oxidized the O/W interfacial film materials, viscous polymers, and compounds responsible for the COD, which was a promising result for the triple effects.