Kaiqiao Wu, Victor Francia, Shuxian Jiang, Marc-Olivier Coppens
Employing oscillatory gas flows to create ordered bubble dynamics in fluidized beds represents a promising approach in reactor design, enhancing efficiency, scalability, and control. This study reports an extensive experimental campaign that identifies the operational regime for structuring Geldart B fluidized beds, introducing a novel pattern recognition algorithm to quantify flow stability and distinguish between “structured” and “unstructured” oscillating beds. The analysis reveals the characteristic features of structured units, including enhanced scalability, homogeneity with narrower bubble size and separation distributions, controlled bubble dynamics, and compartmentalized solid mixing. A nondimensional bubble size, derived from natural frequency and two-phase theory, is proposed to describe the relationship between oscillation characteristics and bubble nucleation. This allows the formulation of a general map to fine-tune oscillating bed operations. The study provides the first comprehensive framework for real-time control of structured beds and sets the stage for further exploration in process intensification and scaling.
{"title":"An experimental flow regime map to dynamically structure gas–solid bubbling fluidized beds","authors":"Kaiqiao Wu, Victor Francia, Shuxian Jiang, Marc-Olivier Coppens","doi":"10.1002/aic.18681","DOIUrl":"https://doi.org/10.1002/aic.18681","url":null,"abstract":"Employing oscillatory gas flows to create ordered bubble dynamics in fluidized beds represents a promising approach in reactor design, enhancing efficiency, scalability, and control. This study reports an extensive experimental campaign that identifies the operational regime for structuring Geldart B fluidized beds, introducing a novel pattern recognition algorithm to quantify flow stability and distinguish between “structured” and “unstructured” oscillating beds. The analysis reveals the characteristic features of structured units, including enhanced scalability, homogeneity with narrower bubble size and separation distributions, controlled bubble dynamics, and compartmentalized solid mixing. A nondimensional bubble size, derived from natural frequency and two-phase theory, is proposed to describe the relationship between oscillation characteristics and bubble nucleation. This allows the formulation of a general map to fine-tune oscillating bed operations. The study provides the first comprehensive framework for real-time control of structured beds and sets the stage for further exploration in process intensification and scaling.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"30 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lithium is becoming increasingly important due to its indispensable role in lithium-ion batteries. The direct extraction of lithium from salt lakes, which are a main source of lithium, is challenging due to the coexistence of many interfering alkali and alkaline earth metals. In this work, we report that a synergistic solvent extraction (SSX) system containing 2,9-dialkyl-1,10-phenanthroline and a hydrophobic anion ([NTf2]−) could extract lithium selectively with a high lithium loading capacity from solutions containing both alkali (sodium, potassium) and alkaline earth metals (magnesium, calcium), enabling the direct recovery of lithium from complex salt lakes. The outstanding lithium extraction performance of the SSX system is unprecedented, to the best knowledge of the authors. Through various characterizations and X-ray diffraction of the complex crystals, the extraction mechanism has been revealed. This SSX system will potentially promote more efficient recovery of lithium from salt lakes.
由于锂离子电池中不可或缺的作用，锂正变得越来越重要。盐湖是锂的主要来源，从盐湖中直接萃取锂具有挑战性，因为盐湖中同时存在多种干扰碱金属和碱土金属。在这项工作中，我们报告了一种含有 2,9 二烷基-1,10-菲罗啉和疏水阴离子（[NTf2]-）的协同溶剂萃取（SSX）系统，该系统可以从含有碱金属（钠、钾）和碱土金属（镁、钙）的溶液中选择性地萃取锂，并具有较高的锂负载能力，从而实现了从复杂盐湖中直接回收锂。据作者所知，SSX 系统出色的锂萃取性能是前所未有的。通过对复杂晶体的各种表征和 X 射线衍射，萃取机理已被揭示。这种 SSX 系统将有可能促进从盐湖中更有效地回收锂。
{"title":"Highly selective lithium extraction by forming ion pairs using 2,9-Dialkyl-1,10-Phenanthrolines and a hydrophobic anion","authors":"Xiao Geng, Jianfeng Zhang, Benzheng Xia, Yuqiu Guan, Qiyu Meng, Zhuojun Jiang, Yifan Zhang, Bharat Prasad Sharma, Yufeng Liang, Liangrong Yang, Zheng Li","doi":"10.1002/aic.18704","DOIUrl":"https://doi.org/10.1002/aic.18704","url":null,"abstract":"Lithium is becoming increasingly important due to its indispensable role in lithium-ion batteries. The direct extraction of lithium from salt lakes, which are a main source of lithium, is challenging due to the coexistence of many interfering alkali and alkaline earth metals. In this work, we report that a synergistic solvent extraction (SSX) system containing 2,9-dialkyl-1,10-phenanthroline and a hydrophobic anion ([NTf<sub>2</sub>]<sup>−</sup>) could extract lithium selectively with a high lithium loading capacity from solutions containing both alkali (sodium, potassium) and alkaline earth metals (magnesium, calcium), enabling the direct recovery of lithium from complex salt lakes. The outstanding lithium extraction performance of the SSX system is unprecedented, to the best knowledge of the authors. Through various characterizations and X-ray diffraction of the complex crystals, the extraction mechanism has been revealed. This SSX system will potentially promote more efficient recovery of lithium from salt lakes.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"55 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amirsalar Bagheri, Thiago Oliveira Cabral, Davood B. Pourkargar
This paper presents an advanced machine learning-based framework designed for predictive modeling, state estimation, and feedback control of ammonia synthesis reactor dynamics. A high-fidelity two-dimensional multiphysics model is employed to generate a comprehensive dataset that captures variable dynamics under various operational conditions. Surrogate long short-term memory neural networks are trained to enable real-time predictions and model-based control. Additionally, a feedforward neural network is developed to estimate the outlet ammonia concentration and hotspot temperature using spatially distributed temperature readings, thereby addressing the challenges associated with real-time concentration and maximum temperature measurements. The machine learning-based predictive modeling and state estimation methods are integrated into a model predictive control architecture to regulate ammonia synthesis. Simulation results demonstrate that the machine learning surrogates accurately represent the nonlinear process dynamics with minimal discrepancy while reducing optimization costs compared to the high-fidelity model, ensuring adaptability and effective guidance of the reactor to desired set points.
{"title":"Integrated learning-based estimation and nonlinear predictive control of an ammonia synthesis reactor","authors":"Amirsalar Bagheri, Thiago Oliveira Cabral, Davood B. Pourkargar","doi":"10.1002/aic.18732","DOIUrl":"https://doi.org/10.1002/aic.18732","url":null,"abstract":"This paper presents an advanced machine learning-based framework designed for predictive modeling, state estimation, and feedback control of ammonia synthesis reactor dynamics. A high-fidelity two-dimensional multiphysics model is employed to generate a comprehensive dataset that captures variable dynamics under various operational conditions. Surrogate long short-term memory neural networks are trained to enable real-time predictions and model-based control. Additionally, a feedforward neural network is developed to estimate the outlet ammonia concentration and hotspot temperature using spatially distributed temperature readings, thereby addressing the challenges associated with real-time concentration and maximum temperature measurements. The machine learning-based predictive modeling and state estimation methods are integrated into a model predictive control architecture to regulate ammonia synthesis. Simulation results demonstrate that the machine learning surrogates accurately represent the nonlinear process dynamics with minimal discrepancy while reducing optimization costs compared to the high-fidelity model, ensuring adaptability and effective guidance of the reactor to desired set points.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"87 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142968595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The presence of aromatics in diesel oil significantly reduces its overall quality. Ionic liquids (ILs) combined with extraction technology were proposed to separate three typical bicyclic aromatics and two monocyclic aromatics from diesel oils. The solubility of IL in raffinate phase was introduced as a crucial factor in IL screening process. The accuracy of COSMO-RS model was evaluated using 2942 LLE data points. 1,3-dimethylimidazolium methylsulfate was considered a suitable extractive solvent. The optimal operating conditions were identified by varying the extraction temperatures, solvent ratios, and stages. Heptane was used as a back-extractive solvent to recover IL; the regenerative and humidity stability of selected IL were proven. The separation mechanisms were explored through molecular dynamic simulation and quantum chemistry calculation. Cation plays a more critical role in the extraction process than anion. The extraction performance mainly depends on the π–π stacking and C–H···O H-bond formed between BAHs molecules and IL.
{"title":"Experimental and molecular thermodynamics insights into separating bicyclic aromatics from diesel oil with ionic liquids","authors":"Qinghua Liu, Minghao Song, Fei Zhao, Chengmin Gui, Jichang Liu, Zhigang Lei, Guoxuan Li","doi":"10.1002/aic.18729","DOIUrl":"https://doi.org/10.1002/aic.18729","url":null,"abstract":"The presence of aromatics in diesel oil significantly reduces its overall quality. Ionic liquids (ILs) combined with extraction technology were proposed to separate three typical bicyclic aromatics and two monocyclic aromatics from diesel oils. The solubility of IL in raffinate phase was introduced as a crucial factor in IL screening process. The accuracy of COSMO-RS model was evaluated using 2942 LLE data points. 1,3-dimethylimidazolium methylsulfate was considered a suitable extractive solvent. The optimal operating conditions were identified by varying the extraction temperatures, solvent ratios, and stages. Heptane was used as a back-extractive solvent to recover IL; the regenerative and humidity stability of selected IL were proven. The separation mechanisms were explored through molecular dynamic simulation and quantum chemistry calculation. Cation plays a more critical role in the extraction process than anion. The extraction performance mainly depends on the π–π stacking and C–H···O H-bond formed between BAHs molecules and IL.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"86 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fragkiskos Tzirakis, Luis A. Diaz, Ioannis Chararas, Daniel Molina Montes de Oca, Zeyu Zhao, Panos Seferlis, Ioannis Tsivintzelis, Athanasios I. Papadopoulos
Solvent-based electrochemical CO2 reduction (CO2R) enables the production of chemicals or fuels using CO2 from a preceding absorption process. Employing previously tested CO2 capture solvents does not ensure their suitability for either CO2R or integrated CO2 absorption-reduction. We propose solvent selection criteria that include the CO2 solubility, kinetic constant, ionic conductivity, concentration of the bicarbonate, carbamate, and solvent cation in the CO2-loaded solution, and sustainability indicators. They are implemented for solvent selection (a) from novel, aqueous mixtures of N-methylcyclohexylamine (MCA) with piperazine (PZ), 2-amino-2-methyl-1-propanol (AMP), potassium hydroxide (KOH), and potassium chloride (KCl) and (b) from aqueous monoethanolamine (MEA), AMP, KOH, MCA, and PZ solutions. Versions of a modified Kent-Eisenberg model for strong bases, carbamate, and non-carbamate-forming amine solutions are developed and parameterized through experimental equilibrium measurements. CO2R experimental results are presented for solutions of KOH and MCA + KOH, as these indicate desired trade-offs for CO2 absorption and reduction.
{"title":"Selection of solvents for integrated CO2 absorption and electrochemical reduction systems","authors":"Fragkiskos Tzirakis, Luis A. Diaz, Ioannis Chararas, Daniel Molina Montes de Oca, Zeyu Zhao, Panos Seferlis, Ioannis Tsivintzelis, Athanasios I. Papadopoulos","doi":"10.1002/aic.18734","DOIUrl":"https://doi.org/10.1002/aic.18734","url":null,"abstract":"Solvent-based electrochemical CO<sub>2</sub> reduction (CO<sub>2</sub>R) enables the production of chemicals or fuels using CO<sub>2</sub> from a preceding absorption process. Employing previously tested CO<sub>2</sub> capture solvents does not ensure their suitability for either CO<sub>2</sub>R or integrated CO<sub>2</sub> absorption-reduction. We propose solvent selection criteria that include the CO<sub>2</sub> solubility, kinetic constant, ionic conductivity, concentration of the bicarbonate, carbamate, and solvent cation in the CO<sub>2</sub>-loaded solution, and sustainability indicators. They are implemented for solvent selection (a) from novel, aqueous mixtures of <i>N</i>-methylcyclohexylamine (MCA) with piperazine (PZ), 2-amino-2-methyl-1-propanol (AMP), potassium hydroxide (KOH), and potassium chloride (KCl) and (b) from aqueous monoethanolamine (MEA), AMP, KOH, MCA, and PZ solutions. Versions of a modified Kent-Eisenberg model for strong bases, carbamate, and non-carbamate-forming amine solutions are developed and parameterized through experimental equilibrium measurements. CO<sub>2</sub>R experimental results are presented for solutions of KOH and MCA + KOH, as these indicate desired trade-offs for CO<sub>2</sub> absorption and reduction.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"3 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A major challenge in the extractive denitrogenation (EDN) of fuel oils lies in achieving high nitrogen removal efficiency with minimal extractant usage. To address this, a series of Cu-based ionic liquids (ILs) ([Bmim]Cl/CuCl2-X) with different cation-to-anion ratios were synthesized and characterized. The cation-to-anion ratio was found to be crucial in determining the predominant anions present in the ILs. Among the synthesized Cu-based ILs, [Bmim]Cl/CuCl2-1 exhibited outstanding EDN performance, achieving 100% nitrogen removal with minimal ionic liquid consumption. The anion [CuCl3]− was identified as playing a key role in the EDN process, where the unoccupied orbitals of Cu and the chloridion in [CuCl3]− facilitate effective coordination with nitrogen atoms in organic nitrogen compounds. This coordination forms Lewis acid–base interactions, which are essential for deep EDN. The study not only introduces an efficient Cu-based ionic liquid but also provides insights into optimizing ionic liquid design for better extraction performance.
{"title":"Deep extractive denitrogenation with Cu-based ionic liquids and mechanistic insights","authors":"Peiwen Wu, Bangzhu Wang, Hongping Li, Shaojie Ma, Linlin Chen, Jixing Liu, Yanhong Chao, Wenshuai Zhu, Chunming Xu","doi":"10.1002/aic.18739","DOIUrl":"https://doi.org/10.1002/aic.18739","url":null,"abstract":"A major challenge in the extractive denitrogenation (EDN) of fuel oils lies in achieving high nitrogen removal efficiency with minimal extractant usage. To address this, a series of Cu-based ionic liquids (ILs) ([Bmim]Cl/CuCl<sub>2</sub>-<i>X</i>) with different cation-to-anion ratios were synthesized and characterized. The cation-to-anion ratio was found to be crucial in determining the predominant anions present in the ILs. Among the synthesized Cu-based ILs, [Bmim]Cl/CuCl<sub>2</sub>-1 exhibited outstanding EDN performance, achieving 100% nitrogen removal with minimal ionic liquid consumption. The anion [CuCl<sub>3</sub>]<sup>−</sup> was identified as playing a key role in the EDN process, where the unoccupied orbitals of Cu and the chloridion in [CuCl<sub>3</sub>]<sup>−</sup> facilitate effective coordination with nitrogen atoms in organic nitrogen compounds. This coordination forms Lewis acid–base interactions, which are essential for deep EDN. The study not only introduces an efficient Cu-based ionic liquid but also provides insights into optimizing ionic liquid design for better extraction performance.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"58 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ke Xue, Hai Liu, Peng Kou, Yan Zhou, Yan Zhang, Zhaoyou Zhu, Jianguang Qi, Yinglong Wang
Efficient and selective extraction of lithium from sodium-rich systems is crucial for meeting the growing demand for lithium and achieving green development goals. In this study, we synthesized three hydrophobic deep eutectic solvents (HDES) using trioctylphosphine oxide and β-diketones for the separation of alkali metal ions. Experimental results indicated that the chosen extractants exhibit excellent Li+ extraction capability under alkaline conditions, and the extraction capacity of HDES for Li+ is superior to that of their components. Thermodynamic function calculations revealed that the Li+ extraction reaction is exothermic. A study of the factors affecting Li+ extraction efficiency and separation coefficients, and the recyclability of HDES, was conducted, achieving efficient recovery of lithium from solutions. Additionally, Fourier-transform infrared spectroscopy analysis and quantum chemical calculations elucidated the extraction mechanism. This study aims to provide a theoretical basis and a green approach for the selective recovery of Li+ from high Na/Li aqueous solutions.
{"title":"Highly selective deep eutectic solvents for the recovery of lithium from high sodium concentration aqueous solutions","authors":"Ke Xue, Hai Liu, Peng Kou, Yan Zhou, Yan Zhang, Zhaoyou Zhu, Jianguang Qi, Yinglong Wang","doi":"10.1002/aic.18679","DOIUrl":"https://doi.org/10.1002/aic.18679","url":null,"abstract":"Efficient and selective extraction of lithium from sodium-rich systems is crucial for meeting the growing demand for lithium and achieving green development goals. In this study, we synthesized three hydrophobic deep eutectic solvents (HDES) using trioctylphosphine oxide and <i>β</i>-diketones for the separation of alkali metal ions. Experimental results indicated that the chosen extractants exhibit excellent Li<sup>+</sup> extraction capability under alkaline conditions, and the extraction capacity of HDES for Li<sup>+</sup> is superior to that of their components. Thermodynamic function calculations revealed that the Li<sup>+</sup> extraction reaction is exothermic. A study of the factors affecting Li<sup>+</sup> extraction efficiency and separation coefficients, and the recyclability of HDES, was conducted, achieving efficient recovery of lithium from solutions. Additionally, Fourier-transform infrared spectroscopy analysis and quantum chemical calculations elucidated the extraction mechanism. This study aims to provide a theoretical basis and a green approach for the selective recovery of Li<sup>+</sup> from high Na/Li aqueous solutions.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"28 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142935658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Long He, Hanguang Xie, Yuan Zong, Ling Zhao, Gance Dai
The twin-liquid film, which combines wall-bounded film supported by a solid wall and confined-free film through the opening window, has been investigated on a plate with multi-windows. The interaction of wall-bounded film and confined free film has been discussed and the optimal window configurations are obtained with consideration of mass transfer enhancement as well as film stability. The mass transfer rate of the opening window plate is increased by 1.9–2.6 times compared with the solid plate. The acceleration and thinning of the confined-free film are the primary causes of its mass transfer enhancement, with additional contributions from the thinning of the wall-bounded film. To achieve the highest mass transfer efficiency as viscosity increases and diffusion coefficient decreases, it is crucial to maximize the window size without compromising film formation. Twin-liquid films show promising applications in the reactors involving highly viscous fluids such as carbon capture and devolatilization.
{"title":"Enhancing interfacial mass transfer for high-viscosity fluids: Hydrodynamic and mass transfer by twin-liquid film","authors":"Long He, Hanguang Xie, Yuan Zong, Ling Zhao, Gance Dai","doi":"10.1002/aic.18708","DOIUrl":"https://doi.org/10.1002/aic.18708","url":null,"abstract":"The twin-liquid film, which combines wall-bounded film supported by a solid wall and confined-free film through the opening window, has been investigated on a plate with multi-windows. The interaction of wall-bounded film and confined free film has been discussed and the optimal window configurations are obtained with consideration of mass transfer enhancement as well as film stability. The mass transfer rate of the opening window plate is increased by 1.9–2.6 times compared with the solid plate. The acceleration and thinning of the confined-free film are the primary causes of its mass transfer enhancement, with additional contributions from the thinning of the wall-bounded film. To achieve the highest mass transfer efficiency as viscosity increases and diffusion coefficient decreases, it is crucial to maximize the window size without compromising film formation. Twin-liquid films show promising applications in the reactors involving highly viscous fluids such as carbon capture and devolatilization.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"28 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142935245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work examines natural convection effects in the non-vacuum-based dual insulation layers of liquid hydrogen storage tanks. Specifically, we consider a dual-layer insulation system in which the inner layer (near the cold boundary) is a hydrogen-filled porous material, while the outer layer (near the warm boundary) is a nitrogen-filled porous medium. We use linear instability theory to determine the critical Rayleigh number for the onset of convective motions, accounting for full physical property variation. We show that the highly unstable density stratification can lead to sub-critical bifurcations and the co-existence of conduction and convective states. We present computed bifurcation diagrams, along with flow patterns and temperature profiles of the emerging convective states. Due to sub-critical bifurcations, in order to avoid convective motions and minimize the boil-off rate, the insulation needs to be designed such that the Rayleigh number is below the limit point of the convective branch.
{"title":"Analysis of natural convection effects in non-vacuum-based insulation layers of large-scale liquid hydrogen tanks","authors":"Swapnil Sharma, Vemuri Balakotaiah","doi":"10.1002/aic.18725","DOIUrl":"https://doi.org/10.1002/aic.18725","url":null,"abstract":"This work examines natural convection effects in the non-vacuum-based dual insulation layers of liquid hydrogen storage tanks. Specifically, we consider a dual-layer insulation system in which the inner layer (near the cold boundary) is a hydrogen-filled porous material, while the outer layer (near the warm boundary) is a nitrogen-filled porous medium. We use linear instability theory to determine the critical Rayleigh number for the onset of convective motions, accounting for full physical property variation. We show that the highly unstable density stratification can lead to sub-critical bifurcations and the co-existence of conduction and convective states. We present computed bifurcation diagrams, along with flow patterns and temperature profiles of the emerging convective states. Due to sub-critical bifurcations, in order to avoid convective motions and minimize the boil-off rate, the insulation needs to be designed such that the Rayleigh number is below the limit point of the convective branch.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"73 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142924940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stepan Sibirtsev, Lukas Thiel, Andrey Kirsanov, Andreas Jupke
Dense-packed zones (DPZs) are crucial in designing equipment for liquid-liquid phase separation processes, as the DPZ height affects apparatus size. This article presents an open-access simulation approach to determine droplet contact numbers and probabilities, which are vital for modeling the deformation and coalescence of polydisperse droplets in a DPZ. The simulation is applied to three technical cases to assess how droplet size distribution (DSD) shapes impact contact numbers and probabilities. Sensitivity analysis reveals that broader DSDs and larger droplet classes lead to higher contact numbers. In contrast, contact probability is primarily determined by droplet class diameter and its number probability within the DSD, showing an almost linear relationship. These results highlight the significance of DSD shape and droplet class diameter in predicting droplet contact numbers and probabilities in DPZs, providing valuable insights for future modeling of liquid-liquid phase separation.
{"title":"Droplet contact numbers and contact probabilities in liquid-liquid dense-packed zones","authors":"Stepan Sibirtsev, Lukas Thiel, Andrey Kirsanov, Andreas Jupke","doi":"10.1002/aic.18723","DOIUrl":"https://doi.org/10.1002/aic.18723","url":null,"abstract":"Dense-packed zones (DPZs) are crucial in designing equipment for liquid-liquid phase separation processes, as the DPZ height affects apparatus size. This article presents an open-access simulation approach to determine droplet contact numbers and probabilities, which are vital for modeling the deformation and coalescence of polydisperse droplets in a DPZ. The simulation is applied to three technical cases to assess how droplet size distribution (DSD) shapes impact contact numbers and probabilities. Sensitivity analysis reveals that broader DSDs and larger droplet classes lead to higher contact numbers. In contrast, contact probability is primarily determined by droplet class diameter and its number probability within the DSD, showing an almost linear relationship. These results highlight the significance of DSD shape and droplet class diameter in predicting droplet contact numbers and probabilities in DPZs, providing valuable insights for future modeling of liquid-liquid phase separation.","PeriodicalId":120,"journal":{"name":"AIChE Journal","volume":"18 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142917652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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