E. Ivashkina, E. Ivanchina, I. Dolganov, V. Chuzlov, A. Kotelnikov, I. Dolganova, R. Khakimov
H2SO4-catalysed isobutane alkylation with alkenes is an important industrial process used to obtain high-octane alkylate. In this process, the concentration of H2SO4 is one of the main parameters. For alkylation, sulphuric acid containing 88%–98% monohydrate is typically used. However, only a H2SO4 concentration of 95%–96% enables alkylate with the maximum octane number to be obtained. Changes in H2SO4 concentration due to decontamination are the main cause of process variations. Therefore, it is necessary to maintain the reactor acid concentration at a constant level by regulating the supply of fresh catalyst and pumping out any spent acid. The main reasons for the decrease in the H2SO4 concentration are accumulation of high-molecular organic compounds and dilution by water. One way to improve and predict unsteady alkylation processes is to develop a mathematical model that considers catalyst deactivation. In the present work, the formation reactions of undesired substances were used in the description of the alkylation process, indicating the sensitivity of the prediction to H2SO4 activity variations. This was used for calculation the optimal technological modes ensuring the maximum selectivity and stability of the chemical–technological system under varying hydrocarbon feedstock compositions.
{"title":"Nonsteady-state mathematical modelling of H2SO4-catalysed alkylation of isobutane with alkenes","authors":"E. Ivashkina, E. Ivanchina, I. Dolganov, V. Chuzlov, A. Kotelnikov, I. Dolganova, R. Khakimov","doi":"10.2516/OGST/2021017","DOIUrl":"https://doi.org/10.2516/OGST/2021017","url":null,"abstract":"H2SO4-catalysed isobutane alkylation with alkenes is an important industrial process used to obtain high-octane alkylate. In this process, the concentration of H2SO4 is one of the main parameters. For alkylation, sulphuric acid containing 88%–98% monohydrate is typically used. However, only a H2SO4 concentration of 95%–96% enables alkylate with the maximum octane number to be obtained. Changes in H2SO4 concentration due to decontamination are the main cause of process variations. Therefore, it is necessary to maintain the reactor acid concentration at a constant level by regulating the supply of fresh catalyst and pumping out any spent acid. The main reasons for the decrease in the H2SO4 concentration are accumulation of high-molecular organic compounds and dilution by water. One way to improve and predict unsteady alkylation processes is to develop a mathematical model that considers catalyst deactivation. In the present work, the formation reactions of undesired substances were used in the description of the alkylation process, indicating the sensitivity of the prediction to H2SO4 activity variations. This was used for calculation the optimal technological modes ensuring the maximum selectivity and stability of the chemical–technological system under varying hydrocarbon feedstock compositions.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77232189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Farhad Fazlollahi, Sajjad Asadizadeh, Milad Ahmadi Khoshooei, M. R. S. Birjandi, M. Sarkari
Hydrogen sulfide exists mostly as a detrimental byproduct in the gas processing units as well as refineries, and it must be eliminated from natural gas streams. In a Sulfur Recovery Unit (SRU), hydrogen sulfide is converted into the elemental sulfur during the modified Claus process. Efficiency of sulfur recovery units significantly depends on the reaction furnace temperature. In this work, the effect of oxygen and acid gas enrichment on the reaction furnace temperature and accordingly on sulfur recovery is studied, using both numerical modeling and process simulation. Then, simulation and numerical model are benchmarked against the experimental data of an SRU unit. The validated model provides spotlight on optimizing the upstream sulfur removal unit as well as the oxygen purification process. Two cases of acid gas streams with low and high H2S content, 30% and 50%, are studied to investigate the effect of operating parameters on the overall recovery. Finally, average errors of the models are presented. According to the absolute difference with experimental values, the developed numerical model shows great potential for accurately estimating overall efficiency of the recovery unit.
{"title":"Investigating efficiency improvement in sulfur recovery unit using process simulation and numerical modeling","authors":"Farhad Fazlollahi, Sajjad Asadizadeh, Milad Ahmadi Khoshooei, M. R. S. Birjandi, M. Sarkari","doi":"10.2516/OGST/2020093","DOIUrl":"https://doi.org/10.2516/OGST/2020093","url":null,"abstract":"Hydrogen sulfide exists mostly as a detrimental byproduct in the gas processing units as well as refineries, and it must be eliminated from natural gas streams. In a Sulfur Recovery Unit (SRU), hydrogen sulfide is converted into the elemental sulfur during the modified Claus process. Efficiency of sulfur recovery units significantly depends on the reaction furnace temperature. In this work, the effect of oxygen and acid gas enrichment on the reaction furnace temperature and accordingly on sulfur recovery is studied, using both numerical modeling and process simulation. Then, simulation and numerical model are benchmarked against the experimental data of an SRU unit. The validated model provides spotlight on optimizing the upstream sulfur removal unit as well as the oxygen purification process. Two cases of acid gas streams with low and high H2S content, 30% and 50%, are studied to investigate the effect of operating parameters on the overall recovery. Finally, average errors of the models are presented. According to the absolute difference with experimental values, the developed numerical model shows great potential for accurately estimating overall efficiency of the recovery unit.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77310846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reservoir simulation is a powerful technique to predict the amount of produced hydrocarbon. After a solid representation of the natural fracture geometry, an accurate simulation model and a physical reservoir model that account for different flow regimes should be developed. Many models based on dual-continuum approaches presented in the literature rely on the Pseudo-Steady-State (PSS) assumption to model the inter-porosity flow. Due to the low permeability in such reservoirs, the transient period could reach several years. Thus, the PSS assumption becomes unjustified. The numerical solution adopted by the Multiple INteracting Continua (MINC) method was able to simulate the transient effects previously overlooked by dual-continuum approaches. However, its accuracy drops with increasing fracture network complexity. A special treatment of the MINC method, i.e., the MINC Proximity Function (MINC–PF) was introduced to address the latter problem. And yet, the MINC–PF suffers a limitation that arises from the existence of several grid-blocks within a studied cell. In this work, this limitation is discussed and two possible solutions (transmissibility recalculation/adjusting the Proximity Function by accounting for nearby fractures) are put forward. Both proposed methods have demonstrated their applicability and effectiveness once compared to a reference solution.
{"title":"The MINC proximity function for fractured reservoirs flow modeling with non-uniform block distribution","authors":"N. Farah, Ali Ghadboun","doi":"10.2516/OGST/2020099","DOIUrl":"https://doi.org/10.2516/OGST/2020099","url":null,"abstract":"Reservoir simulation is a powerful technique to predict the amount of produced hydrocarbon. After a solid representation of the natural fracture geometry, an accurate simulation model and a physical reservoir model that account for different flow regimes should be developed. Many models based on dual-continuum approaches presented in the literature rely on the Pseudo-Steady-State (PSS) assumption to model the inter-porosity flow. Due to the low permeability in such reservoirs, the transient period could reach several years. Thus, the PSS assumption becomes unjustified. The numerical solution adopted by the Multiple INteracting Continua (MINC) method was able to simulate the transient effects previously overlooked by dual-continuum approaches. However, its accuracy drops with increasing fracture network complexity. A special treatment of the MINC method, i.e., the MINC Proximity Function (MINC–PF) was introduced to address the latter problem. And yet, the MINC–PF suffers a limitation that arises from the existence of several grid-blocks within a studied cell. In this work, this limitation is discussed and two possible solutions (transmissibility recalculation/adjusting the Proximity Function by accounting for nearby fractures) are put forward. Both proposed methods have demonstrated their applicability and effectiveness once compared to a reference solution.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78039475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of nanocatalyst composition and calcination parameters on the performance of the Fe–Mn–Ce ternary nanocatalysts supported on alumina granules in a laboratory fixed bed microreactor have been evaluated. Nanocatalysts were synthesized by incipient wetness impregnation under vacuum method (simultaneous impregnation of metal species). The samples used for hydrogenation of carbon monoxide via Fischer-Tropsch synthesis. The optimum nanocatalyst composition for production of light olefins (C=2 – C=4) from synthesis gas is 75 wt%Fe–20 wt%Mn–5 wt%Ce. The calcination parameters (temperature, time and atmosphere) were investigated and their effects on the structure and performance of the nanocatalysts were determined. The maximum ratio of olefins/(methane + paraffin) and the best activity and selectivity belonged to the nanocatalyst which was calcined in static air at 500 °C for 7 h. The nanocatalyst precursors and calcined samples (fresh and used) were characterized by XRD, N2 physisorption, FE‒SEM, EDAX, MAP, TG, DSC, and H2–TPR. The present study results confirm that the structural, morphological and physic-chemical properties of the nanocatalyst have been impressed with metal species and calcination parameters.
{"title":"Assessment of composition and calcination parameters in Fischer-Tropsch synthesis over Fe–Mn–Ce/γ-Al2O3 nanocatalyst","authors":"Reza Roknabadi, A. Mirzaei, H. Atashi","doi":"10.2516/OGST/2020089","DOIUrl":"https://doi.org/10.2516/OGST/2020089","url":null,"abstract":"The effects of nanocatalyst composition and calcination parameters on the performance of the Fe–Mn–Ce ternary nanocatalysts supported on alumina granules in a laboratory fixed bed microreactor have been evaluated. Nanocatalysts were synthesized by incipient wetness impregnation under vacuum method (simultaneous impregnation of metal species). The samples used for hydrogenation of carbon monoxide via Fischer-Tropsch synthesis. The optimum nanocatalyst composition for production of light olefins (C=2 – C=4) from synthesis gas is 75 wt%Fe–20 wt%Mn–5 wt%Ce. The calcination parameters (temperature, time and atmosphere) were investigated and their effects on the structure and performance of the nanocatalysts were determined. The maximum ratio of olefins/(methane + paraffin) and the best activity and selectivity belonged to the nanocatalyst which was calcined in static air at 500 °C for 7 h. The nanocatalyst precursors and calcined samples (fresh and used) were characterized by XRD, N2 physisorption, FE‒SEM, EDAX, MAP, TG, DSC, and H2–TPR. The present study results confirm that the structural, morphological and physic-chemical properties of the nanocatalyst have been impressed with metal species and calcination parameters.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81820820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new oil–gas Minimum Miscibility Pressure (MMP) calculation algorithm is developed in this work based on the classic cell-to-cell simulation model. The proposed algorithm couples the effects of capillary pressure and confinement in the original cell-to-cell simulation model to predict the oil–gas MMPs in a confined space. Given that the original cell-to-cell algorithm relies on the volume predictions of the reservoir fluids in each cell, a volume-translated Peng-Robinson Equation of State (PR-EOS) is applied in this work for improved accuracy on volume calculations of the reservoir fluids. The robustness of the proposed algorithm is examined by performing the confined MMP calculations for four oil–gas systems. The tie-line length extrapolation method is used to determine the oil–gas MMP in confined space. The oil recovery factor calculated by the proposed MMP calculation algorithm is then used to validate the results. First, to achieve stable modeling results for all four examples, a total cell number of 500 is determined by examining the variations in the oil recovery as a function of cell number. Then, by calculating the oil recovery factor near the MMP region, it is found that the MMP determined by tie-line length method is slightly lower than the inflection point of the oil recovery curve. Through the case studies, the effects of temperature, pore radius, and injection gas impurity on the confined oil–gas MMP calculations are studied in detail. It is found that the oil–gas MMP is reduced in confined space and the degree of this reduction depends on the pore radius. For all the tested pore radii, the confined MMP first increases and then decreases with an increasing temperature. Furthermore, compared to pure carbon dioxide (CO2) injection, the addition of methane (CH4) in the injection gas increases the oil–gas MMP in confined nanopores. Therefore, it is recommended to control the content of CH4 in the injection gas in order to achieve a more efficient gas injection design.
{"title":"A modified cell-to-cell simulation model to determine the minimum miscibility pressure in tight/shale formations","authors":"Hao Sun, H. Li","doi":"10.2516/ogst/2021031","DOIUrl":"https://doi.org/10.2516/ogst/2021031","url":null,"abstract":"A new oil–gas Minimum Miscibility Pressure (MMP) calculation algorithm is developed in this work based on the classic cell-to-cell simulation model. The proposed algorithm couples the effects of capillary pressure and confinement in the original cell-to-cell simulation model to predict the oil–gas MMPs in a confined space. Given that the original cell-to-cell algorithm relies on the volume predictions of the reservoir fluids in each cell, a volume-translated Peng-Robinson Equation of State (PR-EOS) is applied in this work for improved accuracy on volume calculations of the reservoir fluids. The robustness of the proposed algorithm is examined by performing the confined MMP calculations for four oil–gas systems. The tie-line length extrapolation method is used to determine the oil–gas MMP in confined space. The oil recovery factor calculated by the proposed MMP calculation algorithm is then used to validate the results. First, to achieve stable modeling results for all four examples, a total cell number of 500 is determined by examining the variations in the oil recovery as a function of cell number. Then, by calculating the oil recovery factor near the MMP region, it is found that the MMP determined by tie-line length method is slightly lower than the inflection point of the oil recovery curve. Through the case studies, the effects of temperature, pore radius, and injection gas impurity on the confined oil–gas MMP calculations are studied in detail. It is found that the oil–gas MMP is reduced in confined space and the degree of this reduction depends on the pore radius. For all the tested pore radii, the confined MMP first increases and then decreases with an increasing temperature. Furthermore, compared to pure carbon dioxide (CO2) injection, the addition of methane (CH4) in the injection gas increases the oil–gas MMP in confined nanopores. Therefore, it is recommended to control the content of CH4 in the injection gas in order to achieve a more efficient gas injection design.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85842434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kaituo Jiao, Peng Wang, Yi Wang, Boyu Yu, B. Bai, Qianqian Shao, Xin-ran Wang
The development of natural gas pipeline network towards larger scale and throughput has urged better reliability of the pipeline network to satisfy transportation requirement. Previously, studies of optimizing natural gas pipeline network have been mainly focused on reducing operating cost, with little concern on the reliability of pipeline network. For a natural gas pipeline network with a variety of components and complicated topology, a multi-objective optimization model of both reliability and operating cost is proposed in this study. Failure of each component and the state of pipeline network under failure conditions are taken into account, and minimum cut set method is employed to calculate the reliability of the pipeline network. The variables to be determined for the optimization objectives are the rotating speed of compressors and the opening of valves. Then the solving procedure of the proposed model is presented based on Decoupled Implicit Method for Efficient Network Simulation (DIMENS) method and NS-saDE algorithm. The validity of the optimization model is ascertained by its application on a complicated pipeline network. The results illustrate that the optimization model can depict the relative relationship between reliability and operating cost for different throughput, by which the operation scheme with both satisfying reliability and operating cost can be obtained. In addition, the customer reliability and the impact of the failure of each pipeline on the whole network can be evaluated quantitatively to identify the consumers and pipelines of maintenance priority. The pipeline network reliability can be improved through proper monitoring and maintenance of these consumers and pipelines.
{"title":"Study on the multi-objective optimization of reliability and operating cost for natural gas pipeline network","authors":"Kaituo Jiao, Peng Wang, Yi Wang, Boyu Yu, B. Bai, Qianqian Shao, Xin-ran Wang","doi":"10.2516/OGST/2021020","DOIUrl":"https://doi.org/10.2516/OGST/2021020","url":null,"abstract":"The development of natural gas pipeline network towards larger scale and throughput has urged better reliability of the pipeline network to satisfy transportation requirement. Previously, studies of optimizing natural gas pipeline network have been mainly focused on reducing operating cost, with little concern on the reliability of pipeline network. For a natural gas pipeline network with a variety of components and complicated topology, a multi-objective optimization model of both reliability and operating cost is proposed in this study. Failure of each component and the state of pipeline network under failure conditions are taken into account, and minimum cut set method is employed to calculate the reliability of the pipeline network. The variables to be determined for the optimization objectives are the rotating speed of compressors and the opening of valves. Then the solving procedure of the proposed model is presented based on Decoupled Implicit Method for Efficient Network Simulation (DIMENS) method and NS-saDE algorithm. The validity of the optimization model is ascertained by its application on a complicated pipeline network. The results illustrate that the optimization model can depict the relative relationship between reliability and operating cost for different throughput, by which the operation scheme with both satisfying reliability and operating cost can be obtained. In addition, the customer reliability and the impact of the failure of each pipeline on the whole network can be evaluated quantitatively to identify the consumers and pipelines of maintenance priority. The pipeline network reliability can be improved through proper monitoring and maintenance of these consumers and pipelines.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80079010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A methodology is suggested for the explicit computation of the absolute permeability and Knudsen diffusion coefficient of tight rocks (shales) from pore structure properties. The pore space is regarded as a pore-and-throat network quantified by the statistical moments of bimodal pore and throat size distributions, pore shape factors, and pore accessibility function. With the aid of percolation theory, analytic equations are developed to express the nitrogen (N2 ) adsorption/desorption isotherms and mercury (Hg) intrusion curve as functions of all pertinent pore structure parameters. A multistep procedure is adopted for the successive estimation of each set of parameters by the inverse modeling of N2 adsorption–desorption isotherms, and Hg intrusion curve. With the aid of critical path analysis of percolation theory, the absolute permeability and Knudsen diffusion coefficient are computed as functions of estimated pore network properties. Application of the methodology to the datasets of several shale samples enables us to evaluate the predictability of the approach.
{"title":"A methodology to predict the gas permeability parameters of tight reservoirs from nitrogen sorption isotherms and mercury porosimetry curves","authors":"C. Tsakiroglou, A. Hinai, R. Rezaee","doi":"10.2516/OGST/2021013","DOIUrl":"https://doi.org/10.2516/OGST/2021013","url":null,"abstract":"A methodology is suggested for the explicit computation of the absolute permeability and Knudsen diffusion coefficient of tight rocks (shales) from pore structure properties. The pore space is regarded as a pore-and-throat network quantified by the statistical moments of bimodal pore and throat size distributions, pore shape factors, and pore accessibility function. With the aid of percolation theory, analytic equations are developed to express the nitrogen (N2 ) adsorption/desorption isotherms and mercury (Hg) intrusion curve as functions of all pertinent pore structure parameters. A multistep procedure is adopted for the successive estimation of each set of parameters by the inverse modeling of N2 adsorption–desorption isotherms, and Hg intrusion curve. With the aid of critical path analysis of percolation theory, the absolute permeability and Knudsen diffusion coefficient are computed as functions of estimated pore network properties. Application of the methodology to the datasets of several shale samples enables us to evaluate the predictability of the approach.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78177781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Ivanchina, Ekaterina Chernyakova, Inna Pchelintseva, D. Poluboyartsev
Catalytic naphtha reforming is extensively applied in petroleum refineries and petrochemical industries to convert low-octane naphtha into high-octane gasoline. Besides, this process is an important source of hydrogen and aromatics obtained as side products. The bifunctional Pt-catalysts for reforming are deactivated by coke formation during an industrial operation. This results to a reduction in the yield and octane number. In this paper modeling and optimization of a semi-egenerative catalytic reforming of naphtha is carried out considering catalyst deactivation and a complex multicomponent composition of a hydrocarbon mixture. The mathematical model of semi-egenerative catalytic reforming considering coke formation process was proposed. The operating parameters (yield, octane number, activity) for different catalysts were predicted and optimized. It was found that a decrease in the pressure range from 1.5 to 1.2 MPa at the temperature 478–481 °C and feedstock space velocity equal to 1.4–1 h induces an increase in the yield for 1–2 wt.% due to an increase in the aromatization reactions rate and a decrease in the hydrocracking reactions rate depending on the feedstock composition and catalyst type. It is shown that the decrease in pressure is limited by the requirements for the catalyst stability due to the increase in the coke formation rate. The criterion of optimality is the yield, expressed in octanes per tons.
{"title":"Mathematical modeling and optimization of semi-regenerative catalytic reforming of naphtha","authors":"E. Ivanchina, Ekaterina Chernyakova, Inna Pchelintseva, D. Poluboyartsev","doi":"10.2516/ogst/2021041","DOIUrl":"https://doi.org/10.2516/ogst/2021041","url":null,"abstract":"Catalytic naphtha reforming is extensively applied in petroleum refineries and petrochemical industries to convert low-octane naphtha into high-octane gasoline. Besides, this process is an important source of hydrogen and aromatics obtained as side products. The bifunctional Pt-catalysts for reforming are deactivated by coke formation during an industrial operation. This results to a reduction in the yield and octane number. In this paper modeling and optimization of a semi-egenerative catalytic reforming of naphtha is carried out considering catalyst deactivation and a complex multicomponent composition of a hydrocarbon mixture. The mathematical model of semi-egenerative catalytic reforming considering coke formation process was proposed. The operating parameters (yield, octane number, activity) for different catalysts were predicted and optimized. It was found that a decrease in the pressure range from 1.5 to 1.2 MPa at the temperature 478–481 °C and feedstock space velocity equal to 1.4–1 h induces an increase in the yield for 1–2 wt.% due to an increase in the aromatization reactions rate and a decrease in the hydrocracking reactions rate depending on the feedstock composition and catalyst type. It is shown that the decrease in pressure is limited by the requirements for the catalyst stability due to the increase in the coke formation rate. The criterion of optimality is the yield, expressed in octanes per tons.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79210193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Mascle, E. Rosenberg, Berit Roboele, E. Kowalewski, S. Youssef
In this work, unstable displacements were conducted using special equipment designed to run in-situ CT-scanner experiments. All the displacements were conducted on a homogeneous Bentheimer sandstone plug, of 10 cm in diameter and 40 cm in length. Digitations (or fingering) have been observed under varying conditions of injection flowrate, displaced fluid viscosity, and core wettability. They have been characterized at both the core scale, using the core average oil saturation and the water breakthrough; and at the local scale, using the local saturations and had-hoc image processing analysis. It was found that the effect of the different flowing conditions on the front digitations could not be interpreted independently. The oil recovery at brine breakthrough showed a good correlation with the viscous fingering number for the water-wet case. However, a different scaling was observed for the oil-wet case. The interplay of the different flowing conditions mitigates the possibility of constructing a unique scaling number to account for all experimental condition. The local saturation monitoring has provided a new insight to characterize the finger shapes and analyze the production mechanisms. It allowed to distinguish two independent contributions to early breakthrough: viscous dominated digitations and capillary dominated digitations. A two-phases diagram has been constructed to plot and compare these contributions for all flowing conditions. Their evolutions show the main production mechanisms during the flooding. We observed that the viscous digitations were not causing phase trapping at core scale: the core is completely swept after breakthrough. For the water-wet case, we found that the local oil recovery of swept zone remained constant before and after breakthrough while for the oil-wet case it is improving during all the water flooding process.
{"title":"Investigation of waterflood front digitations during immiscible displacements in porous media","authors":"M. Mascle, E. Rosenberg, Berit Roboele, E. Kowalewski, S. Youssef","doi":"10.2516/ogst/2021053","DOIUrl":"https://doi.org/10.2516/ogst/2021053","url":null,"abstract":"In this work, unstable displacements were conducted using special equipment designed to run in-situ CT-scanner experiments. All the displacements were conducted on a homogeneous Bentheimer sandstone plug, of 10 cm in diameter and 40 cm in length. Digitations (or fingering) have been observed under varying conditions of injection flowrate, displaced fluid viscosity, and core wettability. They have been characterized at both the core scale, using the core average oil saturation and the water breakthrough; and at the local scale, using the local saturations and had-hoc image processing analysis. It was found that the effect of the different flowing conditions on the front digitations could not be interpreted independently. The oil recovery at brine breakthrough showed a good correlation with the viscous fingering number for the water-wet case. However, a different scaling was observed for the oil-wet case. The interplay of the different flowing conditions mitigates the possibility of constructing a unique scaling number to account for all experimental condition. The local saturation monitoring has provided a new insight to characterize the finger shapes and analyze the production mechanisms. It allowed to distinguish two independent contributions to early breakthrough: viscous dominated digitations and capillary dominated digitations. A two-phases diagram has been constructed to plot and compare these contributions for all flowing conditions. Their evolutions show the main production mechanisms during the flooding. We observed that the viscous digitations were not causing phase trapping at core scale: the core is completely swept after breakthrough. For the water-wet case, we found that the local oil recovery of swept zone remained constant before and after breakthrough while for the oil-wet case it is improving during all the water flooding process.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79970075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Well placement planning is one of the challenging issues in any field development plan. Reservoir engineers always confront the problem that which point of the field should be drilled to achieve the highest recovery factor and/or maximum sweep efficiency. In this paper, we use Reservoir Opportunity Index (ROI) as a spatial measure of productivity potential for greenfields, which hybridizes the reservoir static properties, and for brownfields, ROI is replaced by Dynamic Measure (DM), which takes into account the current dynamic properties in addition to static properties. The purpose of using these criteria is to diminish the search region of optimization algorithms and as a consequence, reduce the computational time and cost of optimization, which are the main challenges in well placement optimization problems. However, considering the significant subsurface uncertainty, a probabilistic definition of ROI (SROI) or DM (SDM) is needed, since there exists an infinite number of possible distribution maps of static and/or dynamic properties. To build SROI or SDM maps, the k-means clustering technique is used to extract a limited number of characteristic realizations that can reasonably span the uncertainties. In addition, to determine the optimum number of clustered realizations, Higher-Order Singular Value Decomposition (HOSVD) method is applied which can also compress the data for large models in a lower-dimensional space. Additionally, we introduce the multiscale spatial density of ROI or DM (D2ROI and D2DM), which can distinguish between regions of high SROI (or SDM) in arbitrary neighborhood windows from the local SROI (or SDM) maxima with low values in the vicinity. Generally, we develop and implement a new systematic approach for well placement optimization for both green and brownfields on a synthetic reservoir model. This approach relies on the utilization of multi-scale maps of SROI and SDM to improve the initial guess for optimization algorithm. Narrowing down the search region for optimization algorithm can substantially speed up the convergence and hence the computational cost would be reduced by a factor of 4.
{"title":"Generalized Multi-Scale Stochastic Reservoir Opportunity Index for enhanced well placement optimization under uncertainty in green and brownfields","authors":"F. Vaseghi, M. Ahmadi, M. Sharifi, M. Vanhoucke","doi":"10.2516/OGST/2021014","DOIUrl":"https://doi.org/10.2516/OGST/2021014","url":null,"abstract":"Well placement planning is one of the challenging issues in any field development plan. Reservoir engineers always confront the problem that which point of the field should be drilled to achieve the highest recovery factor and/or maximum sweep efficiency. In this paper, we use Reservoir Opportunity Index (ROI) as a spatial measure of productivity potential for greenfields, which hybridizes the reservoir static properties, and for brownfields, ROI is replaced by Dynamic Measure (DM), which takes into account the current dynamic properties in addition to static properties. The purpose of using these criteria is to diminish the search region of optimization algorithms and as a consequence, reduce the computational time and cost of optimization, which are the main challenges in well placement optimization problems. However, considering the significant subsurface uncertainty, a probabilistic definition of ROI (SROI) or DM (SDM) is needed, since there exists an infinite number of possible distribution maps of static and/or dynamic properties. To build SROI or SDM maps, the k-means clustering technique is used to extract a limited number of characteristic realizations that can reasonably span the uncertainties. In addition, to determine the optimum number of clustered realizations, Higher-Order Singular Value Decomposition (HOSVD) method is applied which can also compress the data for large models in a lower-dimensional space. Additionally, we introduce the multiscale spatial density of ROI or DM (D2ROI and D2DM), which can distinguish between regions of high SROI (or SDM) in arbitrary neighborhood windows from the local SROI (or SDM) maxima with low values in the vicinity. Generally, we develop and implement a new systematic approach for well placement optimization for both green and brownfields on a synthetic reservoir model. This approach relies on the utilization of multi-scale maps of SROI and SDM to improve the initial guess for optimization algorithm. Narrowing down the search region for optimization algorithm can substantially speed up the convergence and hence the computational cost would be reduced by a factor of 4.","PeriodicalId":19424,"journal":{"name":"Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80024536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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