Contraction-expansion (CE) static mixers can enable solid-liquid and liquid-liquid dispersion with low energy dissipation, low risk of obstruction, and without moving parts. In this work, the influence of CE elements of different geometries on the imposed turbulence of a flowing liquid has been assessed by a two-dimensional computational fluid dynamic (2D-CFD) simulation. The effect of CE on the dispersion of droplets of an immiscible liquid has also been analysed from simulations, using the volume of fluid (VOF) approach. Direct numerical simulation (DNS) performed by the open-source Gerris Flow Solver software was used to get the velocity fields and turbulence characteristics. Different ratios of CE diameters and lengths were analysed for liquid Reynolds numbers from 500 to 20,000. From simulations, the CE geometry that maximised the average root mean square velocity, as an indicator of turbulence, was determined for different liquid flow rates. It was found that the average RMS had a maximum for a wide range of liquid flow rates when the CE diameter ratio was between 0.55 and 0.59 and the length ratio was between 0.2 and 0.3. Then, a device with seven CE elements with geometrical features within this range was built and used for preparing an oil-in-water emulsion. The test system contained water and sunflower oil (5 % v/v) with the further addition of TritonX100 (0.5 % in volume of the solution) as surfactant. The stability of the emulsions was assessed by measuring the time evolution of turbidity (absorbance at 860 nm), to get the initial separation velocities. The emulsions prepared using the CE device showed initial phase separation rates lower than the one obtained in a stirred flask, evidencing the feasibility of using CE static mixers for preparing emulsions with relatively low energy consumption. Moreover, the emulsions obtained with the CE device, although dependent on the flow rate, showed similar features when obtained with 10, 100 and 250 passes through the CE static mixer.
收缩-膨胀（CE）静态混合器可以实现固液和液液分散，能量耗散小，阻塞风险低，并且没有移动部件。在这项工作中，通过二维计算流体动力学（2D-CFD）模拟评估了不同几何形状的 CE 元件对流动液体的外加湍流的影响。此外，还采用流体体积（VOF）方法，通过模拟分析了 CE 对不相溶液体液滴分散的影响。使用开源的 Gerris Flow Solver 软件进行的直接数值模拟（DNS）获得了速度场和湍流特性。针对 500 到 20,000 的液体雷诺数，分析了 CE 的不同直径和长度比例。通过模拟，确定了不同液体流速下平均均方根速度最大的 CE 几何形状，作为湍流的指标。结果发现，当 CE 直径比介于 0.55 和 0.59 之间，长度比介于 0.2 和 0.3 之间时，平均均方根速度在很大的液体流速范围内达到最大值。然后，制造了一个带有七个 CE 元件的装置，其几何特征在此范围内，并用于制备水包油型乳液。测试系统包含水和葵花籽油（体积分数为 5%），并添加了 TritonX100（溶液体积分数为 0.5%）作为表面活性剂。通过测量浊度（在 860 纳米波长处的吸光度）的时间变化来评估乳液的稳定性，从而获得初始分离速度。使用 CE 设备制备的乳液显示出的初始相分离速率低于在搅拌烧瓶中获得的速率，这证明了使用 CE 静态混合器以相对较低的能耗制备乳液的可行性。此外，使用 CE 设备制备的乳液虽然取决于流速，但通过 CE 静态混合器 10 次、100 次和 250 次后，乳液显示出相似的特征。
{"title":"CFD-aided contraction-expansion static mixer design for oil-in-water emulsification","authors":"María del Pilar Balbi, S. Fleite, M. Cassanello","doi":"10.1515/cppm-2023-0069","DOIUrl":"https://doi.org/10.1515/cppm-2023-0069","url":null,"abstract":"\u0000 Contraction-expansion (CE) static mixers can enable solid-liquid and liquid-liquid dispersion with low energy dissipation, low risk of obstruction, and without moving parts. In this work, the influence of CE elements of different geometries on the imposed turbulence of a flowing liquid has been assessed by a two-dimensional computational fluid dynamic (2D-CFD) simulation. The effect of CE on the dispersion of droplets of an immiscible liquid has also been analysed from simulations, using the volume of fluid (VOF) approach. Direct numerical simulation (DNS) performed by the open-source Gerris Flow Solver software was used to get the velocity fields and turbulence characteristics. Different ratios of CE diameters and lengths were analysed for liquid Reynolds numbers from 500 to 20,000. From simulations, the CE geometry that maximised the average root mean square velocity, as an indicator of turbulence, was determined for different liquid flow rates. It was found that the average RMS had a maximum for a wide range of liquid flow rates when the CE diameter ratio was between 0.55 and 0.59 and the length ratio was between 0.2 and 0.3. Then, a device with seven CE elements with geometrical features within this range was built and used for preparing an oil-in-water emulsion. The test system contained water and sunflower oil (5 % v/v) with the further addition of TritonX100 (0.5 % in volume of the solution) as surfactant. The stability of the emulsions was assessed by measuring the time evolution of turbidity (absorbance at 860 nm), to get the initial separation velocities. The emulsions prepared using the CE device showed initial phase separation rates lower than the one obtained in a stirred flask, evidencing the feasibility of using CE static mixers for preparing emulsions with relatively low energy consumption. Moreover, the emulsions obtained with the CE device, although dependent on the flow rate, showed similar features when obtained with 10, 100 and 250 passes through the CE static mixer.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140243813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Increasing environmental concerns have led to the development of alternative methods for the desulfurization of petroleum crude oil and liquid fuels. Phosphonium-based ionic liquids (PILs) have recently demonstrated promising potential for effective extractive desulfurization (EDS). The present study focuses on the synthesis and application of trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate [THTDP][D2EHP] for EDS of synthetic model fuels and real crude oils. The molecular confirmation and thermal stability of [THTDP][D2EHP] were investigated using FTIR and TGA analyses. In addition, the conductivity, solubility, and viscosity of the synthesized ionic liquid (IL) were analyzed. The impact of reaction time, temperature, and sulfur compounds, such as thiophene, benzothiophene, and dibenzothiophene (DBT), on the desulfurization efficiency from synthetic fuels was also investigated. The results indicated up to 63 and 57 % sulfur removal from DBT-based model fuels and Iranian crude oil, respectively. The optimum extraction conditions were found as 1:1 IL/fuel mass ratio, 35 °C, and 30 min. The findings of this study provide valuable insights into the synthesis and utilization of PILs as promising solvents for extractive desulfurization of crude oil and liquid fuels.
{"title":"Extractive desulfurization of crude petroleum oil and liquid fuels using trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate ionic liquid","authors":"Amin Solouki, Jamal Chaouki","doi":"10.1515/cppm-2023-0077","DOIUrl":"https://doi.org/10.1515/cppm-2023-0077","url":null,"abstract":"\u0000 Increasing environmental concerns have led to the development of alternative methods for the desulfurization of petroleum crude oil and liquid fuels. Phosphonium-based ionic liquids (PILs) have recently demonstrated promising potential for effective extractive desulfurization (EDS). The present study focuses on the synthesis and application of trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate [THTDP][D2EHP] for EDS of synthetic model fuels and real crude oils. The molecular confirmation and thermal stability of [THTDP][D2EHP] were investigated using FTIR and TGA analyses. In addition, the conductivity, solubility, and viscosity of the synthesized ionic liquid (IL) were analyzed. The impact of reaction time, temperature, and sulfur compounds, such as thiophene, benzothiophene, and dibenzothiophene (DBT), on the desulfurization efficiency from synthetic fuels was also investigated. The results indicated up to 63 and 57 % sulfur removal from DBT-based model fuels and Iranian crude oil, respectively. The optimum extraction conditions were found as 1:1 IL/fuel mass ratio, 35 °C, and 30 min. The findings of this study provide valuable insights into the synthesis and utilization of PILs as promising solvents for extractive desulfurization of crude oil and liquid fuels.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140261943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transient responses of reaction–desorption process were predicted from mathematical solutions of modeling equations for CSTR (continuously stirred tank reactor) containing core–shell adsorbent particles. Analytical solutions on the core–shell particles were derived for core–shell spherical, cylindrical, and slab-type morphologies, assuming inert-cores. Unlike continuous adsorber, CSTRs for reaction–desorption process containing spherical particles exhibited the slowest reduction rate of concentration of adsorbate, because the amount of adsorbed component on the particles is the largest among three kinds of particle shapes. Factors affecting the transient concentration in bulk medium of reaction–desorption process were investigated by adjusting inert-core thickness, inlet flow rate, initial concentration of reactant in inflow stream, amount of adsorbent, and Thiele modulus. Concentration profile inside the particles as well as average intra-particle concentration could be also predicted for comparison with bulk concentration of CSTR. For non-linear isotherm and non-linear reaction kinetics, concentration of active component could be predicted by solving non-linear coupled differential equation using finite element method. For connected CSTRs in series, systems of reaction-diffusion equations were solved by finite element method to study the effect of number of connected reactors. When the number of reactors was sufficiently large, the reactor system could be approximated to fixed bed reactor for reaction–desorption process.
{"title":"Modeling of reaction–desorption process by core–shell particles dispersed in continuously stirred tank reactor (CSTR)","authors":"Young-Sang Cho, H. Nguyen","doi":"10.1515/cppm-2023-0081","DOIUrl":"https://doi.org/10.1515/cppm-2023-0081","url":null,"abstract":"\u0000 Transient responses of reaction–desorption process were predicted from mathematical solutions of modeling equations for CSTR (continuously stirred tank reactor) containing core–shell adsorbent particles. Analytical solutions on the core–shell particles were derived for core–shell spherical, cylindrical, and slab-type morphologies, assuming inert-cores. Unlike continuous adsorber, CSTRs for reaction–desorption process containing spherical particles exhibited the slowest reduction rate of concentration of adsorbate, because the amount of adsorbed component on the particles is the largest among three kinds of particle shapes. Factors affecting the transient concentration in bulk medium of reaction–desorption process were investigated by adjusting inert-core thickness, inlet flow rate, initial concentration of reactant in inflow stream, amount of adsorbent, and Thiele modulus. Concentration profile inside the particles as well as average intra-particle concentration could be also predicted for comparison with bulk concentration of CSTR. For non-linear isotherm and non-linear reaction kinetics, concentration of active component could be predicted by solving non-linear coupled differential equation using finite element method. For connected CSTRs in series, systems of reaction-diffusion equations were solved by finite element method to study the effect of number of connected reactors. When the number of reactors was sufficiently large, the reactor system could be approximated to fixed bed reactor for reaction–desorption process.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140083600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nabil Bouarra, Soumaya Kherouf, Nawel Nadji, Loubna Nouri, A. Boudjemaa, Souad Djerad, K. Bacharı
QSPR is a powerful tool for elucidating the correlation between chemical structure and property for both natural and synthesized compounds. In the present work, the half-wave reduction potential for a set of aziridinylquinones (Anticancer Agents [AA]) is modelled using a quantitative structure-electrochemistry relationship (QSER) based on multilinear regression (MLR) and artificial neural network (ANN). Molecular descriptors introduced in this work were computed using the Dragon software (V5). Before the model’s generation, using the Kennard and Stone algorithm, the data set of 84 aziridinylquinones was divided into training and prediction sets consisting of 70 % and 30 % of data points. Quantitative Structure Electrochemistry Relationship (QSER) models were developed using the Genetic Algorithm Multiple Linear Regressions (GA-MLR) and an Artificial Neural Network (ANN). The coefficient of determination (R 2) and Root Mean Squared Error of prediction (RMSE) were mentioned to demonstrate the QSER model’s prediction abilities. Calculated R 2 and RMSEval values for the MLR model were 0.858 and 0.054, respectively. The R 2 and RMSEval values for the ANN training set were calculated to be 0.914 and 0.050, respectively. Findings show that GA is a powerful tool for selecting variables in QSER analysis. Comparing the two employed regression methods showed that ANN is superior to MLR in predictive ability.
{"title":"Quantitative structure-electrochemistry relationship modeling of a series of anticancer agents using MLR and ANN approaches","authors":"Nabil Bouarra, Soumaya Kherouf, Nawel Nadji, Loubna Nouri, A. Boudjemaa, Souad Djerad, K. Bacharı","doi":"10.1515/cppm-2023-0024","DOIUrl":"https://doi.org/10.1515/cppm-2023-0024","url":null,"abstract":"\u0000 QSPR is a powerful tool for elucidating the correlation between chemical structure and property for both natural and synthesized compounds. In the present work, the half-wave reduction potential for a set of aziridinylquinones (Anticancer Agents [AA]) is modelled using a quantitative structure-electrochemistry relationship (QSER) based on multilinear regression (MLR) and artificial neural network (ANN). Molecular descriptors introduced in this work were computed using the Dragon software (V5). Before the model’s generation, using the Kennard and Stone algorithm, the data set of 84 aziridinylquinones was divided into training and prediction sets consisting of 70 % and 30 % of data points. Quantitative Structure Electrochemistry Relationship (QSER) models were developed using the Genetic Algorithm Multiple Linear Regressions (GA-MLR) and an Artificial Neural Network (ANN). The coefficient of determination (R\u0000 2) and Root Mean Squared Error of prediction (RMSE) were mentioned to demonstrate the QSER model’s prediction abilities. Calculated R\u0000 2 and RMSEval values for the MLR model were 0.858 and 0.054, respectively. The R\u0000 2 and RMSEval values for the ANN training set were calculated to be 0.914 and 0.050, respectively. Findings show that GA is a powerful tool for selecting variables in QSER analysis. Comparing the two employed regression methods showed that ANN is superior to MLR in predictive ability.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140426105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Adithya Kashyap, Suresh Kumar Chiluka, Seshagiri Rao Ambati, G. U. Bhaskar Babu
Performance and robustness are essential characteristics for the application of unstable time-delayed systems. As tasks become more complex, traditional control methods cannot meet such demands for performance and robustness. The present work aims to develop fractional order-based controllers for enhanced Smith predictor-based unstable first-order plus time-delayed systems (FOPTD) with improved performance and robustness. In the current work, fractional order controllers using a Genetic Algorithm (GA) are designed with enhanced SP (Smith Predictor) structure to control unstable first-order time-delayed processes to improve performance. Furthermore, in the feedback path a fractional order (FO) filter is used to further improve robustness and performance. A systematic methodology is proposed for obtaining the optimum fractional order filter parameters based on the minimization of Integral Absolute Error (IAE). The recommended approach is beneficial to balance the necessary tradeoff between performance and robustness. Also, the proposed method provides flexibility in tuning the degree of freedom by adding a fractional order integrator, thus leading to robust performance. The efficacy of the recommended controller is analyzed by simulating numerical examples from the literature. The proposed controller provides enhanced performance and robustness compared to the literature.
{"title":"Smith predictor based fractional order controller design for improved performance and robustness of unstable FOPTD processes","authors":"A. Adithya Kashyap, Suresh Kumar Chiluka, Seshagiri Rao Ambati, G. U. Bhaskar Babu","doi":"10.1515/cppm-2023-0086","DOIUrl":"https://doi.org/10.1515/cppm-2023-0086","url":null,"abstract":"\u0000 Performance and robustness are essential characteristics for the application of unstable time-delayed systems. As tasks become more complex, traditional control methods cannot meet such demands for performance and robustness. The present work aims to develop fractional order-based controllers for enhanced Smith predictor-based unstable first-order plus time-delayed systems (FOPTD) with improved performance and robustness. In the current work, fractional order controllers using a Genetic Algorithm (GA) are designed with enhanced SP (Smith Predictor) structure to control unstable first-order time-delayed processes to improve performance. Furthermore, in the feedback path a fractional order (FO) filter is used to further improve robustness and performance. A systematic methodology is proposed for obtaining the optimum fractional order filter parameters based on the minimization of Integral Absolute Error (IAE). The recommended approach is beneficial to balance the necessary tradeoff between performance and robustness. Also, the proposed method provides flexibility in tuning the degree of freedom by adding a fractional order integrator, thus leading to robust performance. The efficacy of the recommended controller is analyzed by simulating numerical examples from the literature. The proposed controller provides enhanced performance and robustness compared to the literature.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140428185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The kinetic study on sophorolipids (SLs) production by Candida catenulata from glucose, raw sunflower soapstock was investigated at different initial concentrations ranging from 0 to 100 g L−1. The Monod model with a maximum specific growth rate (μ max) of 0.0167 h−1 and half-saturation coefficient (K S ) of 6.91 g L−1 best described the cell growth kinetics of C. catenulata on glucose. The best-fitted constants of the Monod model for raw sunflower soapstock were μ max = 0.0157 h−1 and K S = 16.01 g L−1. Determination of Luedeking-Piret constants indicated SLs mainly produced as an associated growth product in the systems. Dynamic features of the fermentation were modeled using the obtained constants and results showed the prediction power of the developed model in describing the behavior of the process. Also, a modified kinetic model was developed for the dynamic modeling of the dual carbon sources system.
在 0 至 100 g L-1 的不同初始浓度下，研究了以葡萄糖、生葵花皂素为原料的 catenulata 白色念珠菌生产槐脂（SLs）的动力学。莫诺模型的最大比生长速率（μ max）为 0.0167 h-1，半饱和系数（K S ）为 6.91 g L-1 ，该模型最准确地描述了白念珠菌在葡萄糖上的细胞生长动力学。莫诺模型对生葵花皂素的最佳拟合常数为 μ max = 0.0157 h-1 和 K S = 16.01 g L-1。对 Luedeking-Piret 常量的测定表明，SLs 主要是作为一种伴生产物在系统中产生的。利用所获得的常数对发酵的动态特征进行了建模，结果表明所建立的模型在描述过程行为方面具有很强的预测能力。此外，还为双碳源系统的动态建模建立了一个改进的动力学模型。
{"title":"Kinetic studies and dynamic modeling of sophorolipids production by Candida catenulata using different carbon sources","authors":"M. Nourouzpour, Alireza Habibi, Fariba Amiri","doi":"10.1515/cppm-2023-0078","DOIUrl":"https://doi.org/10.1515/cppm-2023-0078","url":null,"abstract":"\u0000 The kinetic study on sophorolipids (SLs) production by Candida catenulata from glucose, raw sunflower soapstock was investigated at different initial concentrations ranging from 0 to 100 g L−1. The Monod model with a maximum specific growth rate (μ\u0000 max) of 0.0167 h−1 and half-saturation coefficient (K\u0000 \u0000 S\u0000 ) of 6.91 g L−1 best described the cell growth kinetics of C. catenulata on glucose. The best-fitted constants of the Monod model for raw sunflower soapstock were μ\u0000 max = 0.0157 h−1 and K\u0000 \u0000 S\u0000 = 16.01 g L−1. Determination of Luedeking-Piret constants indicated SLs mainly produced as an associated growth product in the systems. Dynamic features of the fermentation were modeled using the obtained constants and results showed the prediction power of the developed model in describing the behavior of the process. Also, a modified kinetic model was developed for the dynamic modeling of the dual carbon sources system.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139958139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roushni Kumari, Bhaskar Kasina, Raghvendra Gupta, H. J. Pant, Rajesh Kumar Upadhyay
Abstract The flow generated in a gas-liquid stirred tank reactor highly depends on the design of the impeller and sparger. To better understand the contact between the phases and the mass and heat transfer rates, especially when the mass transfer is the limiting step, it is crucial to investigate the hydrodynamics generated by the impellers and its impact on the bubble size and their distribution, and gas volume fraction. In this work, experimental and numerical studies are performed with a novel mixed impeller in a pilot scale (T = 0.486 m) gas-liquid stirred tank reactor. The Sauter mean diameter, mean bubble diameter and bubble size distribution is determined at the different radial and axial regions by using high-speed imaging technique. Further, Euler-Euler simulations are performed to find the detailed flow field of novel mixed impeller used in the current study. Finally, the gassed power to impeller swept volume ratio is determined from the CFD and correlated with the Sauter mean diameter measured in the experiment in the impeller discharge region. It is found that the novel mixed impeller used in current work shows the similar behavior as the Rushton impeller in the impeller discharge region and it also provide good axial mixing.
{"title":"Effect of novel mixed impeller on local bubble size and flow regime transition in pilot scale gas-liquid stirred tank reactor","authors":"Roushni Kumari, Bhaskar Kasina, Raghvendra Gupta, H. J. Pant, Rajesh Kumar Upadhyay","doi":"10.1515/cppm-2023-0050","DOIUrl":"https://doi.org/10.1515/cppm-2023-0050","url":null,"abstract":"Abstract The flow generated in a gas-liquid stirred tank reactor highly depends on the design of the impeller and sparger. To better understand the contact between the phases and the mass and heat transfer rates, especially when the mass transfer is the limiting step, it is crucial to investigate the hydrodynamics generated by the impellers and its impact on the bubble size and their distribution, and gas volume fraction. In this work, experimental and numerical studies are performed with a novel mixed impeller in a pilot scale (T = 0.486 m) gas-liquid stirred tank reactor. The Sauter mean diameter, mean bubble diameter and bubble size distribution is determined at the different radial and axial regions by using high-speed imaging technique. Further, Euler-Euler simulations are performed to find the detailed flow field of novel mixed impeller used in the current study. Finally, the gassed power to impeller swept volume ratio is determined from the CFD and correlated with the Sauter mean diameter measured in the experiment in the impeller discharge region. It is found that the novel mixed impeller used in current work shows the similar behavior as the Rushton impeller in the impeller discharge region and it also provide good axial mixing.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139524907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work presents a superstructure for maximizing the annual profit of biodiesel production with Advanced Interactive Multidimensional Modeling System (AIMMS). The novelty features are the combination of pinch-based heat integration with a wide range of biodiesel feedstocks and the application of superstructure to evaluate the effect of uncertainties on the optimized design. The case study is a pilot refinery with the infeed capacity of 8000 tonnes feedstock per year. The biodiesel production route from tallow with reactive distillation technology and a heterogeneous acid catalyst has the highest total annual profit of 3.5 million USDs. The heating and cooling utilities can be reduced by 30 % with the heat integration. The result from the sensitivity analysis shows that the biodiesel and feedstock prices, and the production capacity have the most pronounced effects. From technical assessment, the reactive distillation process is the best choice for biodiesel production from different feedstocks.
{"title":"Development of a superstructure optimization framework with heat integration for the production of biodiesel","authors":"T. Huynh, M. Franke, Edwin Zondervan","doi":"10.1515/cppm-2023-0071","DOIUrl":"https://doi.org/10.1515/cppm-2023-0071","url":null,"abstract":"\u0000 This work presents a superstructure for maximizing the annual profit of biodiesel production with Advanced Interactive Multidimensional Modeling System (AIMMS). The novelty features are the combination of pinch-based heat integration with a wide range of biodiesel feedstocks and the application of superstructure to evaluate the effect of uncertainties on the optimized design. The case study is a pilot refinery with the infeed capacity of 8000 tonnes feedstock per year. The biodiesel production route from tallow with reactive distillation technology and a heterogeneous acid catalyst has the highest total annual profit of 3.5 million USDs. The heating and cooling utilities can be reduced by 30 % with the heat integration. The result from the sensitivity analysis shows that the biodiesel and feedstock prices, and the production capacity have the most pronounced effects. From technical assessment, the reactive distillation process is the best choice for biodiesel production from different feedstocks.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139612958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhiqiang Long, Buqing Zhang, Guoqing Liu, Zhengxin Wu, Qiang Yan
Abstract In the current essay, the numerical investigation of heat transfer in an exchanger containing nanofluid with Cu nanoparticles in the presence of a new inserter is carried out. The equations governing the turbulent fluid flow have been solved utilizing single-phase models with the aid of the finite volume method in ANSYS-FLUENT software using the k-ε turbulence model for the Re number ranging from 4000 to 8000. Furthermore, the influence of Reynolds number, nanoparticle volume fraction, and geometric characteristics of turbulator on the friction factor and Nusselt number have been scrutinized. Outcomes reveal that the newly introduced inserter performs well and increases the Nusselt number by roughly 34–54 times and the friction coefficient by approximately 1.8–3.2 times compared to the smooth tube. It is also observed that a 2 % increase in the nanoparticles volume fraction has resulted in a rise in the Nusselt number by around 92 %. To attain the optimal performance of the presented turbulator, the longitudinal distance between the inserters is recommended as S/D = 5.27, for which Performance evaluation criteria values in the range of 3.01–9.23 in the Reynolds range under investigation are acquired.
{"title":"Enhancing heat transfer in tube heat exchanger containing water/Cu nanofluid by using turbulator","authors":"Zhiqiang Long, Buqing Zhang, Guoqing Liu, Zhengxin Wu, Qiang Yan","doi":"10.1515/cppm-2023-0079","DOIUrl":"https://doi.org/10.1515/cppm-2023-0079","url":null,"abstract":"Abstract In the current essay, the numerical investigation of heat transfer in an exchanger containing nanofluid with Cu nanoparticles in the presence of a new inserter is carried out. The equations governing the turbulent fluid flow have been solved utilizing single-phase models with the aid of the finite volume method in ANSYS-FLUENT software using the k-ε turbulence model for the Re number ranging from 4000 to 8000. Furthermore, the influence of Reynolds number, nanoparticle volume fraction, and geometric characteristics of turbulator on the friction factor and Nusselt number have been scrutinized. Outcomes reveal that the newly introduced inserter performs well and increases the Nusselt number by roughly 34–54 times and the friction coefficient by approximately 1.8–3.2 times compared to the smooth tube. It is also observed that a 2 % increase in the nanoparticles volume fraction has resulted in a rise in the Nusselt number by around 92 %. To attain the optimal performance of the presented turbulator, the longitudinal distance between the inserters is recommended as S/D = 5.27, for which Performance evaluation criteria values in the range of 3.01–9.23 in the Reynolds range under investigation are acquired.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138971715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The present paper presents a numerical investigation of heat transfer in an exchanger fitted with a modified conical-shaped turbulator containing water/Fe2O3 nanofluid. The study aims to address the critical need for improved heat exchanger efficiency, a vital component in various industries, including the chemical, power generation, and food industries. The work focuses on achieving enhanced heat transfer performance within a smaller volume, a primary goal of modern technology and industrial processes. The innovation in this study lies in the design and analysis of a novel conical turbulator, which has not been explored extensively in the context of heat exchangers fitted with nanofluids. Unlike traditional methods, which often rely on active or semi-active means to enhance heat transfer, this research introduces a passive approach through the incorporation of turbulators. Specifically, the study investigates the use of perforated cone-shaped turbulators in conjunction with nanofluids to boost heat transfer performance. The research employs state-of-the-art computational fluid dynamics (CFD) models, allowing for a comprehensive evaluation of the turbulator’s performance across a wide range of Reynolds numbers (Re = 4000–20,000). It further examines the influence of various turbulator parameters, nanoparticle content, and geometry on heat transfer efficiency. Key findings indicate that the modified turbulator exhibits exceptional performance, increasing Nusselt numbers by 3.4–5.4 times and friction coefficients by 2.3–1.8 times compared to smooth pipes. Particularly noteworthy is the 92 % increase in the Nusselt number achieved with a mere 2 % increase in the Fe2O3 nanoparticle content. The present study introduces a novel passive heat transfer enhancement method using perforated cone-shaped turbulators and nanofluids, filling a significant gap in existing research. The innovative turbulator design and its substantial performance improvements offer promising prospects for achieving higher heat exchanger efficiency, making it a valuable contribution to thermal systems and heat transfer engineering.
{"title":"Enhancing heat exchanger efficiency with novel perforated cone-shaped turbulators and nanofluids: a computational study","authors":"Limin Wang, Junqiang Wang, Jiajia Tang, Xuliong Zho","doi":"10.1515/cppm-2023-0034","DOIUrl":"https://doi.org/10.1515/cppm-2023-0034","url":null,"abstract":"Abstract The present paper presents a numerical investigation of heat transfer in an exchanger fitted with a modified conical-shaped turbulator containing water/Fe2O3 nanofluid. The study aims to address the critical need for improved heat exchanger efficiency, a vital component in various industries, including the chemical, power generation, and food industries. The work focuses on achieving enhanced heat transfer performance within a smaller volume, a primary goal of modern technology and industrial processes. The innovation in this study lies in the design and analysis of a novel conical turbulator, which has not been explored extensively in the context of heat exchangers fitted with nanofluids. Unlike traditional methods, which often rely on active or semi-active means to enhance heat transfer, this research introduces a passive approach through the incorporation of turbulators. Specifically, the study investigates the use of perforated cone-shaped turbulators in conjunction with nanofluids to boost heat transfer performance. The research employs state-of-the-art computational fluid dynamics (CFD) models, allowing for a comprehensive evaluation of the turbulator’s performance across a wide range of Reynolds numbers (Re = 4000–20,000). It further examines the influence of various turbulator parameters, nanoparticle content, and geometry on heat transfer efficiency. Key findings indicate that the modified turbulator exhibits exceptional performance, increasing Nusselt numbers by 3.4–5.4 times and friction coefficients by 2.3–1.8 times compared to smooth pipes. Particularly noteworthy is the 92 % increase in the Nusselt number achieved with a mere 2 % increase in the Fe2O3 nanoparticle content. The present study introduces a novel passive heat transfer enhancement method using perforated cone-shaped turbulators and nanofluids, filling a significant gap in existing research. The innovative turbulator design and its substantial performance improvements offer promising prospects for achieving higher heat exchanger efficiency, making it a valuable contribution to thermal systems and heat transfer engineering.","PeriodicalId":9935,"journal":{"name":"Chemical Product and Process Modeling","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138603750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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