Browsing by Author "Dinkov R."
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Item Alternative Options for Ebullated Bed Vacuum Residue Hydrocracker Naphtha Utilization(2023-12-01) Stratiev D.; Shishkova I.; Ivanov M.; Dinkov R.; Toteva V.; Angelova D.; Kolev I.; Tavlieva M.; Yordanov D.The vacuum residue hydrocracker naphtha (VRHN) is a chemically unstable product that during storage changes its colour and forms sediments after two weeks. It cannot be directly exported from the refinery without improving its chemical stability. In this research, the hydrotreatment of H-Oil naphtha with straight run naphtha in a commercial hydrotreater, its co-processing with fluid catalytic cracking (FCC) gasoline in a commercial Prime-G+ post-treater, and its co-processing with vacuum gas oil (VGO) in a commercial FCC unit were discussed. The hydrotreatment improves the chemical stability of H-Oil naphtha and reduces its sulphur content to 3 ppm. The Prime-G+ co-hydrotreating increases the H-Oil naphtha blending research octane number (RON) by 6 points and motor octane number (MON) by 9 points. The FCC co-cracking with VGO enhances the blending RON by 11.5 points and blending MON by 17.6 points. H-Oil naphtha conversion to gaseous products (C1–C4 hydrocarbons) in the commercial FCC unit was found to be 50%. The use of ZSM 5 containing catalyst additive during processing H-Oil naphtha showed to lead to FCC gasoline blending octane enhancement by 2 points. This enabled an increment of low octane number naphtha in the commodity premium near zero sulphur automotive gasoline by 2.4 vol.% and substantial improvement of refinery margin. The processing of H-Oil naphtha in the FCC unit leads also to energy saving as a result of an equivalent lift steam substitution in the FCC riser.Item Commercial Ebullated Bed Vacuum Residue Hydrocracking Performance Improvement during Processing Difficult Feeds(2023-03-01) Georgiev B.E.; Stratiev D.S.; Argirov G.S.; Nedelchev A.; Dinkov R.; Shishkova I.K.; Ivanov M.; Atanassov K.; Ribagin S.; Nikolov Palichev G.; Nenov S.; Sotirov S.; Sotirova E.; Pilev D.; Stratiev D.D.The Urals and Siberian vacuum residues are considered difficult to process in the ebullated bed hydrocracking because of their increased tendency to form sediments. Their achievable conversion rate reported in the literature is 60%. Intercriteria analysis was used to assess data from a commercial vacuum residue hydrocracker during processing blends from three vacuum residues: Urals, Siberian Light, and Basra Heavy. The analysis revealed that the main contributors to conversion enhancement is hydrodemetallization (HDM) and the first reactor ΔT augmentation. The increase of HDM from 40 to 98% and the first reactor ΔT (ΔT(R1)) from 49 to 91 °C were associated with a vacuum residue conversion enhancement of 62.0 to 82.7 wt.%. The developed nonlinear regression prediction of conversion from HDM and ΔT(R1) suggests a bigger influence of ΔT(R1) enhancement on conversion augmentation than the HDM increase. The intercriteria analysis evaluation revealed that the higher first reactor ΔT suppresses the sediment formation rate to a greater extent than the higher HDM. During processing Basrah Heavy vacuum residue, a reduction in hydrodeasphaltization (HDAs) from 73.6 to 55.2% and HDM from 88 to 81% was observed. It was confirmed that HDM and HDAs are interrelated. It was found that the attainment of conversion of 80 wt.% and higher during processing Urals and Siberian Light vacuum residues is possible when the HDM is about 90% and LHSV ≤ 0.19 h−1.Item Commercial Investigation of the Ebullated-Bed Vacuum Residue Hydrocracking in the Conversion Range of 55-93%(2020-12-29) Stratiev D.; Nenov S.; Shishkova I.; Georgiev B.; Argirov G.; Dinkov R.; Yordanov D.; Atanassova V.; Vassilev P.; Atanassov K.The LUKOIL Neftohim Burgas vacuum residue hydrocracking has increased the vacuum residue conversion from 55 to 93% as a result of a proper feed selection, optimal catalyst condition, and the use of a Mo nanodispersed catalyst. It was found that the feed colloidal instability index estimated from the feed saturates, aromatics, resins, and asphaltenes (SARA) data negatively correlated with the conversion. Correlations based on the use of the nonlinear least-squares method, which relates the density to the aromatic structure contents for the straight run and hydrocracked vacuum residues, were developed. Intercriteria analysis was applied to evaluate the relations between the different properties of the straight run and the hydrocracked vacuum residual oils. The density of the hydrocracked vacuum residue measured by dilution with toluene was found to strongly correlate with the conversion, Conradson carbon content, softening point, and Fraasss breaking point.Item Correlations of HTSD to TBP and Bulk Properties to Saturate Content of a Wide Variety of Crude Oils(2023-02-01) Stratiev D.; Dinkov R.; Tavlieva M.; Shishkova I.; Nikolov Palichev G.; Ribagin S.; Atanassov K.; Stratiev D.D.; Nenov S.; Pilev D.; Sotirov S.; Sotirova E.; Simeonov S.; Boyadzhieva V.Forty-eight crude oils with variations in specific gravity (0.782 ≤ SG ≤ 1.002), sulphur content (0.03 ≤ S ≤ 5.6 wt.%), saturate content (23.5 ≤ Sat. ≤ 92.9 wt.%), asphaltene content (0.1 ≤ As ≤ 22.2 wt.%), and vacuum residue content (1.4 ≤ VR ≤ 60.7 wt.%) were characterized with HTSD, TBP, and SARA analyses. A modified SARA analysis of petroleum that allows for the attainment of a mass balance ≥97 wt.% for light crude oils was proposed, a procedure for the simulation of petroleum TBP curves from HTSD data using nonlinear regression and Riazi’s distribution model was developed, and a new correlation to predict petroleum saturate content from specific gravity and pour point with an average absolute deviation of 2.5 wt.%, maximum absolute deviation of 6.6 wt.%, and bias of 0.01 wt.% was developed. Intercriteria analysis was employed to evaluate the presence of statistically meaningful relations between the different petroleum properties and to evaluate the extent of similarity between the studied petroleum crudes. It was found that the extent of similarity between the crude oils based on HTSD analysis data could be discerned from data on the Kw characterization factor of narrow crude oil fractions. The results from this study showed that contrary to the generally accepted concept of the constant Kw characterization factor, the Kw factors of narrow fractions differ from that of crude oil. Moreover, the distributions of Kw factors of the different crudes were different.Item Different nonlinear regression techniques and sensitivity analysis as tools to optimize oil viscosity modeling(2021-10-01) Stratiev D.; Nenov S.; Nedanovski D.; Shishkova I.; Dinkov R.; Stratiev D.D.; Stratiev D.D.; Sotirov S.; Sotirova E.; Atanassova V.; Atanassov K.; Yordanov D.; Angelova N.A.; Ribagin S.; Todorova-Yankova L.Four nonlinear regression techniques were explored to model gas oil viscosity on the base of Walther’s empirical equation. With the initial database of 41 primary and secondary vacuum gas oils, four models were developed with a comparable accuracy of viscosity calculation. The Akaike information criterion and Bayesian information criterion selected the least square relative errors (LSRE) model as the best one. The sensitivity analysis with respect to the given data also revealed that the LSRE model is the most stable one with the lowest values of standard deviations of derivatives. Verification of the gas oil viscosity prediction ability was carried out with another set of 43 gas oils showing remarkably better accuracy with the LSRE model. The LSRE was also found to predict better viscosity for the 43 test gas oils relative to the Aboul Seoud and Moharam model and the Kotzakoulakis and George.Item Empirical Modeling of Viscosities and Softening Points of Straight-Run Vacuum Residues from Different Origins and of Hydrocracked Unconverted Vacuum Residues Obtained in Different Conversions(2022-03-01) Stratiev D.; Nenov S.; Nedanovski D.; Shishkova I.; Dinkov R.; Stratiev D.D.; Stratiev D.D.; Sotirov S.; Sotirova E.; Atanassova V.; Ribagin S.; Atanassov K.; Yordanov D.; Angelova N.A.; Todorova-Yankova L.The use of hydrocracked and straight-run vacuum residues in the production of road pavement bitumen requires a good understanding of how the viscosity and softening point can be modeled and controlled. Scientific reports on modeling of these rheological properties for hydroc-racked and straight-run vacuum residues are scarce. For that reason, 30 straight-run vacuum residues and 33 hydrocracked vacuum residues obtained in a conversion range of 55–93% were investigated, and the characterization data were employed for modeling purposes. An intercriteria analysis was applied to investigate the statistically meaningful relations between the studied vacuum residue properties. It revealed that the straight-run and hydrocracked vacuum residues were completely different, and therefore their viscosity and softening point should be separately modeled. Through the use of nonlinear regression by applying CAS Maple and NLPSolve with the modified Newton iterative method and the vacuum residue bulk properties the viscosity and softening point were modeled. It was found that the straight-run vacuum residue viscosity was best modeled from the molecular weight and specific gravity, whereas the softening point was found to be best modeled from the molecular weight and C7-asphaltene content. The hydrocracked vacuum residue viscosity and softening point were modeled from a single property: the Conradson carbon content. The vacuum residue viscosity models developed in this work were found to allow prediction of the asphaltene content from the molecular weight and specific gravity with an average absolute relative error of 20.9%, which was lower of that of the model of Samie and Mortaheb (Fuel. 2021, 305, 121609)—32.6%.Item Experience in Processing Alternative Crude Oils to Replace Design Oil in the Refinery(2024-06-01) Stratiev D.; Shiskova I.; Toteva V.; Georgiev G.; Dinkov R.; Kolev I.; Petrov I.; Argirov G.; Bureva V.; Ribagin S.; Atanassov K.; Nenov S.; Sotirov S.; Nikolova R.; Veli A.A comprehensive investigation of a highly complex petroleum refinery (Nelson complexity index of 10.7) during the processing of 11 crude oils and an imported atmospheric residue replacing the design Urals crude oil was performed. Various laboratory oil tests were carried out to characterize both crude oils, and their fractions. The results of oil laboratory assays along with intercriteria and regression analyses were employed to find quantitative relations between crude oil mixture quality and refining unit performance. It was found that the acidity of petroleum cannot be judged by its total acid number, and acid crudes with lower than 0.5 mg KOH/g and low sulphur content required repeated caustic treatment enhancement and provoked increased corrosion rate and sodium contamination of the hydrocracking catalyst. Increased fouling in the H-Oil hydrocracker was observed during the transfer of design Urals crude oil to other petroleum crudes. The vacuum residues with higher sulphur, lower nitrogen contents, and a lower colloidal instability index provide a higher conversion rate and lower fouling rate in the H-Oil unit. The regression equations developed in this work allow quantitative assessment of the performance of crucial refining units like the H-Oil, fluid catalytic cracker, naphtha reformer, and gas oil hydrotreatment based on laboratory oil test results.Item INHIBITING SEDIMENT FORMATION IN AN EXTRA LIGHT CRUDE OIL AND IN A HYDROCRACKED ATMOSPHERIC RESIDUE BY COMMERCIAL CHEMICAL ADDITIVES(2022-01-01) Stratiev D.; Shishkova I.; Tavlieva M.; Kirilov K.; Dinkov R.; Yordanov D.; Yankova L.; Toteva V.; Nikolova R.Extra light crude oil from Kazahstan and hydrocracked atmospheric residue from a commercial ebullated bed vacuum residue hydrocracker were investigated to reduce their sediment formation rate by employing 13 commercial chemical additives. Ten of the studied additives were based on the organic acid derivatives. Asphaltene dispersion test was applied in this study to define the most appropriate chemical additive and the optimum treating rate. The additives demonstrated different performance with the distinct oils. All organic acid derivative additives were capable of suppressing the sedimentation in the hydrocracked atmospheric residue, while not all of them were effective in decreasing the sediment formation in the extra light petroleum. The phosphoric acid and poly-iso-butylene succinimide based additives were effective in suppressing the sedimentation in the hydrocracked atmospheric residue while they promoted the formation of sediments in the extra light petroleum. The additive based on 1,2,4-trimethylbenzene was ineffective in decreasing the sedimentation in the hydrocracked atmospheric residue and slightly effective in the suppression of sediment formation in the extra light petroleum.Item Intercriteria Analysis to Diagnose the Reasons for Increased Fouling in a Commercial Ebullated Bed Vacuum Residue Hydrocracker(2022-01-01) Stratiev D.; Shishkova I.; Dinkov R.; Kolev I.; Argirov G.; Ivanov V.; Ribagin S.; Atanassova V.; Atanassov K.; Stratiev D.; Nenov S.; Pilev D.; Yordanov D.The intercriteria analysis developed on the base of intuitionistic fuzziness and index matrices was applied to evaluate processing data of the LUKOIL Neftohim Burgas H-Oil ebullated bed vacuum residue hydrocracker with the aim of revealing the reasons for increased fouling registered during the 3rd cycle of the H-Oil hydrocracker. It was found that when the ratio of the δT of the 1st reactor to the δT of the 2nd reactor gets lower than 2.0, an excessive H-Oil equipment fouling occurs. The fouling was also found to be favored by processing of lower Conradson carbon content vacuum residual oils and increased throughput and depressed by increasing the dosage of the HCAT nanodispersed catalyst. The fouling in the atmospheric tower bottom section is facilitated by a lower aromatic content in the atmospheric tower bottom product. The addition of FCC slurry oil not only increases aromatic content but also dissolves some of the asphaltenes in the atmospheric residual hydrocracked oil and decreases its colloidal instability index. The fouling in the vacuum tower bottom section is facilitated by a higher saturate content in the VTB. Surprisingly, it was found that the asphaltene content in the VTB depresses the fouling rate. No relation was found of the sediment content in the hydrocracked residual oils measured by hot filtration tests and by the centrifuge method to the equipment fouling of the H-Oil hydrocracker.Item Predicting Petroleum SARA Composition from Density, Sulfur Content, Flash Point, and Simulated Distillation Data Using Regression and Artificial Neural Network Techniques(2024-08-01) Shiskova I.; Stratiev D.; Sotirov S.; Sotirova E.; Dinkov R.; Kolev I.; Stratiev D.D.; Nenov S.; Ribagin S.; Atanassov K.; Yordanov D.; van den Berg F.The saturate, aromatic, resin, and asphaltene content in petroleum (SARA composition) provides valuable information about the chemical nature of oils, oil compatibility, colloidal stability, fouling potential, and other important aspects in petroleum chemistry and processing. For that reason, SARA composition data are important for petroleum engineering research and practice. Unfortunately, the results of SARA composition measurements reported by diverse laboratories are frequently very dissimilar and the development of a method to assign SARA composition from oil bulk properties is a question that deserves attention. Petroleum fluids with great variability of SARA composition were employed in this study to model their SARA fraction contents from their density, flash point, sulfur content, and simulated distillation characteristics. Three data mining techniques: intercriteria analysis, regression, and artificial neural networks (ANNs) were applied. It was found that the ANN models predicted with higher accuracy the contents of resins and asphaltenes, whereas the non-linear regression model predicted most accurately the saturate fraction content but with an accuracy that was lower than that reported in the literature regarding uncertainty of measurement. The aromatic content was poorly predicted by all investigated techniques, although the prediction of aromatic content was within the uncertainty of measurement. The performed study suggests that as well as the investigated properties, additional characteristics need to be explored to account for complex petroleum chemistry in order to improve the accuracy of SARA composition prognosis.Item Prediction of Molecular Weight of Petroleum Fluids by Empirical Correlations and Artificial Neuron Networks(2023-02-01) Stratiev D.; Sotirov S.; Sotirova E.; Nenov S.; Dinkov R.; Shishkova I.; Kolev I.V.; Yordanov D.; Vasilev S.; Atanassov K.; Simeonov S.; Palichev G.N.The exactitude of petroleum fluid molecular weight correlations affects significantly the precision of petroleum engineering calculations and can make process design and trouble-shooting inaccurate. Some of the methods in the literature to predict petroleum fluid molecular weight are used in commercial software process simulators. According to statements made in the literature, the correlations of Lee–Kesler and Twu are the most used in petroleum engineering, and the other methods do not exhibit any significant advantages over the Lee–Kesler and Twu correlations. In order to verify which of the proposed in the literature correlations are the most appropriate for petroleum fluids with molecular weight variation between 70 and 1685 g/mol, 430 data points for boiling point, specific gravity, and molecular weight of petroleum fluids and individual hydrocarbons were extracted from 17 literature sources. Besides the existing correlations in the literature, two different techniques, nonlinear regression and artificial neural network (ANN), were employed to model the molecular weight of the 430 petroleum fluid samples. It was found that the ANN model demonstrated the best accuracy of prediction with a relative standard error (RSE) of 7.2%, followed by the newly developed nonlinear regression correlation with an RSE of 10.9%. The best available molecular weight correlations in the literature were those of API (RSE = 12.4%), Goosens (RSE = 13.9%); and Riazi and Daubert (RSE = 15.2%). The well known molecular weight correlations of Lee–Kesler, and Twu, for the data set of 430 data points, exhibited RSEs of 26.5, and 30.3% respectively.Item Prediction of Refractive Index of Petroleum Fluids by Empirical Correlations and ANN(2023-08-01) Palichev G.N.; Stratiev D.; Sotirov S.; Sotirova E.; Nenov S.; Shishkova I.; Dinkov R.; Atanassov K.; Ribagin S.; Stratiev D.D.; Pilev D.; Yordanov D.The refractive index is an important physical property that is used to estimate the structural characteristics, thermodynamic, and transport properties of petroleum fluids, and to determine the onset of asphaltene flocculation. Unfortunately, the refractive index of opaque petroleum fluids cannot be measured unless special experimental techniques or dilution is used. For that reason, empirical correlations, and metaheuristic models were developed to predict the refractive index of petroleum fluids based on density, boiling point, and SARA fraction composition. The capability of these methods to accurately predict refractive index is discussed in this research with the aim of contrasting the empirical correlations with the artificial neural network modelling approach. Three data sets consisting of specific gravity and boiling point of 254 petroleum fractions, individual hydrocarbons, and hetero-compounds (Set 1); specific gravity and molecular weight of 136 crude oils (Set 2); and specific gravity, molecular weight, and SARA composition data of 102 crude oils (Set 3) were used to test eight empirical correlations available in the literature to predict the refractive index. Additionally, three new empirical correlations and three artificial neural network (ANN) models were developed for the three data sets using computer algebra system Maple, NLPSolve with Modified Newton Iterative Method, and Matlab. For Set 1, the most accurate refractive index prediction was achieved by the ANN model, with %AAD of 0.26% followed by the new developed correlation for Set 1 with %AAD of 0.37%. The best literature empirical correlation found for Set 1 was that of Riazi and Daubert (1987), which had %AAD of 0.40%. For Set 2, the best performers were the models of ANN, and the new developed correlation of Set 2 with %AAD of refractive index prediction was 0.21%, and 0.22%, respectively. For Set 3, the ANN model exhibited %AAD of refractive index prediction of 0.156% followed by the newly developed correlation for Set 3 with %AAD of 0.163%, while the empirical correlations of Fan et al. (2002) and Chamkalani (2012) displayed %AAD of 0.584 and 0.552%, respectively.Item Relation of the Content of Sustainable Components (HEFAs) in Blends with Hydrotreated Straight-Run Kerosene to the Properties of Aviation Fuel(2024-06-01) Dinkov R.; Stratiev D.; Andreev I.; Georgiev G.; Angelova M.; Dimitrova R.Z.; Toteva V.An expected increase in the demand for aviation transport service will result in the deterioration of the environment and human health, respectively, due to extra greenhouse gas (GHG) emissions. Concerns from EU institutions about the issue have led to legislation initiatives and, later, to development of Regulation (EU) 2023/2405 for the reduction of GHG emissions via the substitution of fossil kerosene with an increasing share of sustainable components. Hydroprocessed esters and fatty acids (HEFAs) are the most commercially acceptable sustainable alternative but their influence on aviation fuel properties needs to be further evaluated in terms of all required and extended properties, as per ASTM D1655. The main properties, together with the rarely reported upon existent gum, water separation, corrosion, and the electrical conductivity of HEFAs and their blends with fossil kerosene were quantitatively evaluated in this study. For every increase of 10% (v/v) of HEFAs, the following fuel properties improve: the freezing point decreases by 1.3 °C, the smoke point increases by an average of 3 mm, and the specific net energy increases by 0.08 MJ/kg. The acidity of HEFAs are an order of magnitude higher than that of conventional aviation fuel and, thus, close to the limit. The existent gum of the studied SAF is higher than that of fossil kerosene due to, most probably, the presence of non-evaporated residual material.Item Role of Catalyst in Optimizing Fluid Catalytic Cracking Performance during Cracking of H-Oil-Derived Gas Oils(2021-03-23) Stratiev D.; Shishkova I.; Ivanov M.; Dinkov R.; Georgiev B.; Argirov G.; Atanassova V.; Vassilev P.; Atanassov K.; Yordanov D.; Popov A.; Padovani A.; Hartmann U.; Brandt S.; Nenov S.; Sotirov S.; Sotirova E.Three H-Oil gas oils, heavy atmospheric gas oil (HAGO), light vacuum gas oil (LVGO), heavy vacuum gas oil (HVGO), and two their blends with hydrotreated straight run vacuum gas oils (HTSRVGOs) were cracked on two high unit cell size (UCS) lower porosity commercial catalysts and two low UCS higher porosity commercial catalysts. The cracking experiments were performed in an advanced cracking evaluation fluid catalytic cracking (FCC) laboratory unit at 527 °C, 30 s catalyst time on stream, and catalyst-to-oil (CTO) variation between 3.5 and 7.5 wt/wt The two high UCS lower porosity catalysts were more active and more coke selective. However, the difference between conversion of the more active high UCS lower porosity and low UCS higher porosity catalysts at 7.5 wt/wt CTO decreased in the order 10% (HAGO) > 9% (LVGO) > 6% (HVGO) > 4% (80% HTSRVGO/20% H-Oil VGO). Therefore, the catalyst performance is feedstock-dependent. The four studied catalysts along with a blend of one of them with 2% ZSM-5 were examined in a commercially revamped UOP FCC VSS unit. The lower UCS higher porosity catalysts exhibited operation at a higher CTO ratio achieving a similar conversion level with more active higher UCS lower porosity catalysts. However, the higher UCS lower porosity catalysts made 0.67% Δcoke that was higher than the maximum acceptable limit of 0.64% for this particular commercial FCC unit (FCCU), which required excluding the HVGO from the FCC feed blend. The catalyst system containing ZSM-5 increased the LPG yield but did not have an impact on gasoline octane. It was found that the predominant factor that controls refinery profitability related to the FCCU performance is the FCC slurry oil (bottoms) yield.Item Roles of Catalysts and Feedstock in Optimizing the Performance of Heavy Fraction Conversion Processes: Fluid Catalytic Cracking and Ebullated Bed Vacuum Residue Hydrocracking(2024-09-01) Stratiev D.; Shishkova I.; Argirov G.; Dinkov R.; Ivanov M.; Sotirov S.; Sotirova E.; Bureva V.; Nenov S.; Atanassov K.; Stratiev D.; Vasilev S.Petroleum refining has been, is still, and is expected to remain in the next decades the main source of energy required to drive transport for mankind. The demand for automotive and aviation fuels has urged refiners to search for ways to extract more light oil products per barrel of crude oil. The heavy oil conversion processes of ebullated bed vacuum residue hydrocracking (EBVRHC) and fluid catalytic cracking (FCC) can assist refiners in their aim to produce more transportation fuels and feeds for petrochemistry from a ton of petroleum. However, a good understanding of the roles of feed quality and catalyst characteristics is needed to optimize the performance of both heavy oil conversion processes. Three knowledge discovery database techniques—intercriteria and regression analyses, and artificial neural networks—were used to evaluate the performance of commercial FCC and EBVRHC in processing 19 different heavy oils. Seven diverse FCC catalysts were assessed using a cascade and parallel fresh catalyst addition system in an EBVRHC unit. It was found that the vacuum residue conversion in the EBVRHC depended on feed reactivity, which, calculated on the basis of pilot plant tests, varied by 16.4%; the content of vacuum residue (VR) in the mixed EBVRHC unit feed (each 10% fluctuation in VR content leads to an alteration in VR conversion of 1.6%); the reaction temperature (a 1 °C deviation in reaction temperature is associated with a 0.8% shift in VR conversion); and the liquid hourly space velocity (0.01 h-1 change of LHSV leads to 0.85% conversion alteration). The vacuum gas oil conversion in the FCC unit was determined to correlate with feed crackability, which, calculated on the basis of pilot plant tests, varied by 8.2%, and the catalyst ΔCoke (each 0.03% ΔCoke increase reduces FCC conversion by 1%), which was unveiled to depend on FCC feed density and equilibrium FCC micro-activity. The developed correlations can be used to optimize the performance of FCC and EBVRHC units by selecting the appropriate feed slate and catalyst.Item Validation of Diesel Fraction Content in Heavy Oils Measured by High Temperature Simulated Distillation and Physical Vacuum Distillation by Performance of Commercial Distillation Test and Process Simulation(2022-11-01) Stratiev D.; Shishkova I.; Ivanov M.; Dinkov R.; Argirov G.; Vasilev S.; Yordanov D.A gas chromatography high temperature simulation distillation (HTSD: ASTM D 7169), and physical vacuum distillation (ASTM D 1160) were employed to characterize H-Oil vacuum distillates, straight run vacuum distillates, and hydrotreated vacuum distillates with the aim to determine their content of diesel fraction and evaluate the possible higher extraction of diesel fraction from the heavy oils. The ASTM D 7169 reported about six times as high diesel fraction content in H-Oil heavy distillates as that reported by the ASTM D 1160 method. Performing a commercial distillation column test along with a simulation of the column operation using data of both ASTM methods and a software process simulator revealed that the HTSD is the more valid method for proper determination of the diesel fraction content in heavy oils. The software process simulation of the commercial distillation column operation suggests that the HTSD could be considered as a true boiling point distillation method for heavy oils. The separation of the diesel fraction from the H-Oil heavy distillates quantified by the HTSD could deliver oil refining profit improvement in the amount of six digits USD per year.