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Internal circulation in carrier phase slugs and its influence on the local hydrodynamics in reactive liquid-liquid segmented flow: Visualisation and PIV studies

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CHEMICAL ENGINEERING SCIENCE 2024年 295卷

作者： Koshy, A. Ray, S. Das, G. Natl Inst Technol Dept Chem Engn Raipur India BIT Mesra Dept Chem Engn Ranchi India Indian Inst Technol Dept Chem Engn Kharagpur India

Local velocity profiles and fluid circulation in liquid - liquid segmented flow significantly influence interphase mass transfer and associated chemical reactions in reduced dimensions. The present study considers a mass transfer-controlled pseudo first order reaction between iodine dissolved in toluene plugs (dispersed phase) and aqueous sodium hydroxide solution (carrier phase). The circulation patterns in the aqueous slugs observed during PIV experiments are correlated with the overall reaction rate. The extent of reaction is identified by decolourisation of the toluene plugs which is a result of iodine depletion. The experiments reveal that an increase in dispersed phase flow rate increases the circulation rate and local velocity within the carrier phase slugs. This is accompanied by propagation of reactant depletion zone from top to bottom within the organic plug and flattening of plug bottom. Nevertheless, the circulation remains axisymmetric with the stagnation region unchanged at r(0 similar to) 0.74R.

关键词： Liquid-liquid flow Mesoscale segmented flow PIV Internal circulation Stagnant zone

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segmented flow capillary microreactors for determination of kinetic rate constants of reactive zinc extraction system

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CHEMICAL ENGINEERING SCIENCE 2022年 247卷

作者： Zhang, Dong Fu, Longyang Xu, Guangze Zhang, Yadong Zhengzhou Univ Sch Chem Engn Zhengzhou 450001 Peoples R China Zhengzhou Univ Jiyuan Res Inst Jiyuan 459000 Peoples R China

Conventional techniques for kinetic rate constant acquisition are limited by diffusive transport, which can be well addressed by microfluidic techniques. segmented flow capillary microreactors were used for the first time in this study to obtain kinetic rate constants for a reactive zinc extraction system. The influences of initial zinc ion concentration, total flow velocity, pH of the aqueous phase, and ionic strength on the kinetic rate constant determination were investigated. The control regimes were determined with the ratio of reaction to total resistance R, and the Hatta number. The kinetic rate constants obtained at low initial zinc concentrations, low acidity and high flow velocities exhibited minor deviations, indicating that the zinc sulfate/D2EHPA system could be under the kinetic control regime with the capillary microreactors, which also demonstrated the viability of the segmented flow approach. The kinetic rate constant data obtained with the segmented flow capillary microreactor from this work were much higher than those obtained from previous studies, which may be attributed to the fact that the microreactor minimizes the influence of diffusive transport. The purpose of this work was to provide reliable kinetic data of the reactive zinc extraction system and to verify the efficiency and superiority of the segmented flow microreactor approach over other techniques. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： segmented flow Capillary microreactor Kinetic rate constant Zinc extraction Kinetic control regime

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Effect of Fluid flow on Crystallization in a segmented flow Microchannel

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JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 2021年第11期54卷 603-+页

作者： Yamasaki, Souta Sotowa, Ken-Ichiro Horikawa, Toshihide Univ Tokushima Grad Sch Technol Ind & Social Sci 2-1 Minamijosanjima Tokushima Tokushima 7708506 Japan Kyoto Univ Grad Sch Engn Nishikyo Ku Kyoto Kyoto 6158510 Japan

segmented flow crystallization has attracted the attention of engineers in the development of drug substance processes, because the crystallization behavior is different from that observed in conventional stirred tanks. Under segmented flow conditions, the crystal size distribution is narrower, and the crystallization rate is higher than that of batch crystallization. However, the phenomenological theory of segmented flow crystallization has not been clarified. The purpose of this study was to gain more insights into segmented flow crystallization phenomena. We focused on the influence of fluid behavior on crystallization. First, we analyzed the motion of crystals in a segmented flow using computational fluid dynamics. Under the assumption that the mass transfer is the rate-determining step of crystal growth, we evaluated how particle and flow conditions contribute to the mass transfer. The shear rate under segmented flow was found to be approximately 16 times greater than that in a stirred tank. The high shear rate induced a high mass transfer rate, which is often observed under segmented flow conditions.

关键词： Continuous Crystallization segmented flow Mass Transfer Computational Fluid Dynamics Shear Rate

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Aerobic oxidation of 2-tert-butyl phenol within gas-liquid segmented flow: Mass transfer characteristics and scale-up

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AICHE JOURNAL 2023年第7期69卷 e18057-e18057页

作者： Liu, Ping Zhang, Jiawei Liu, Kefeng Hu, Xuesheng Gao, Fei Du, Le Zhu, Jiqin Beijing Univ Chem Technol Coll Chem Engn State Key Lab Chem Resource Engn Beijing Peoples R China PetroChina Petrochem Res Inst Beijing Peoples R China

Quantifying the mass transfer of gas-liquid segmented flow in practical reactions is of significant for the scale-up design. However, there is a lack of theoretical guidance to predict operational conditions to meet required the mass transfer in a selective dimension-enlarged microreactor. Herein, the oxidation of 2-tert-butyl phenol (2-TBP) was performed in a selective dimension-enlarged capillary microreactor of 4.35 mm i.d. and optimal operation conditions were obtained. A high 2-tert-butyl-1,-4-benzoquinone (2-TBQ) yield of 73% was achieved within 6 min. Moreover, a quantitative method to assess the mass transfer of gas-liquid segmented flow in practical reaction was developed by introducing a circulation frequency, f(cir), which could provide theoretical guidance to predict operating conditions for the scale-up production. The 2-TBQ productivity is significantly increased from 0.0061 to 0.5068 kg/h, that is, an increase of 83 times, by selective dimension enlarging from 2 mm to 4.35 mm with predicted operating conditions.

关键词： aerobic oxidation circulation frequency mass transfer segmented flow selective dimension enlarging

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High throughput continuous synthesis of size-controlled nanoFe3O4 in segmented flow

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CHEMICAL ENGINEERING JOURNAL 2023年第1期471卷

作者： Jiang, Xiaoyang Li, Sihui Sotowa, Ken-Ichiro Tonomura, Osamu Oh, Tae Hoon Kyoto Univ Dept Chem Engn Nishikyo Ku Kyoto 6158510 Japan Kyoto Univ Dept Mat Chem Nishikyo Ku Kyoto 6158510 Japan

NanoFe3O4, a magnetic nanoparticle, boasts wide-ranging applications, from magnetic separation to imaging, labeling, and remote control of targeted drug delivery. However, the conventional nanoFe3O4 synthesis in a batch reactor is time-and energy-intensive. In the currently developed continuous synthesis strategies, the complexity of the rotating packed bed reactor and the low capacity of the microfluidic chip impedes the application of these devices for the fabrication of nanoFe3O4. Hence, for the continuous synthesis of nanoFe3O4, a simple and convenient device with high throughput is urgently required. Microfluidic technology presents promising approaches that can enhance mass and heat transfer in segmented flow, surpassing the limitations of conventional methods. In this study, continuous synthesis of nanoFe3O4 was achieved in segmented flow within a microchannel, utilizing the coprecipitation method. The influence of iron concentration, reaction temperature, and the Fe2+:Fe3+ ratio on the synthesis of nanoFe3O4 were investigated thoroughly. Based on the results, analyzed through X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), this segmented flow synthesis strategy was proved to be capable of fabricating nanoFe3O4 of approximately 6 nm. Moreover, by increasing the high-speed valve frequency, thus reducing the segment length, the size distribution range of nanoparticles was reduced and uniform nanoparticles were synthesized. The continuous synthesis method developed through our research offers significant advantages over other existing technologies in terms of productivity and manufacturing cost. Therefore, it offers a promising pathway for the industrial-scale continuous synthesis of nanoFe3O4.

关键词： Continuous synthesis High throughput Microchannel segmented flow

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Continuous enantiomeric separation using water-oil-water segmented flow system

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CHEMICAL ENGINEERING JOURNAL 2023年第1期469卷

作者： Muranaka, Yosuke Maki, Taisuke Nakayoshi, Daiki Asano, Shusaku Ikebata, Katsuya Nagaki, Aiichiro Ashikari, Yosuke Mandai, Kyoko Mae, Kazuhiro Kyoto Univ Dept Chem Engn Kyoto Japan Kyushu Univ Inst Mat Chem & Engn Fukuoka Japan Hokkaido Univ Fac Sci Sapporo Japan

The multiphase segmented flow, which consisted of the material, extraction, and recovery phases, was applied to the chiral separation. The use of simultaneous extraction and back-extraction with multiple phases aims to prevent the accumulation of target material in the extraction phase by efficiently removing it in the recovery phase, thereby enabling extraction performance beyond the equilibrium. This study demonstrated the chiral separation of an aqueous racemic amino acid derivative (3,5-dinitrobenzoyl-(R,S)-leucine) with a cinchona alkaloid chiral host. A droplet manipulation system comprising PFA manifolds and valves was utilized to alternately form an acidic material phase slug and a basic recovery phase slug in a 1-octanol oil phase containing the chiral host. Two aqueous phases were collected separately using valves controlled by an optical sensor signal. The manipulation system achieved stable operation across various conditions, including flow rate, residence time, and slug lengths. The enantiomeric excess, which represents the purity of the chirality, could be increased to 50 % through 200 s extraction in a one-step operation.

关键词： Extraction segmented flow Chiral chemical

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Continuous synthesis of 2-tert-butyl phenol oxidation in gas-liquid segmented flow and its kinetic investigation

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CHEMICAL ENGINEERING SCIENCE 2022年 248卷

作者： Liu, Ping Ge, Haowei Lu, Yuheng Wang, Yujun Du, Le Zhu, Jiqin Beijing Univ Chem Technol Coll Chem Engn State Key Lab Chem Resource Engn Beijing 100029 Peoples R China Tsinghua Univ Dept Chem Engn State Key Lab Chem Engn Beijing 100084 Peoples R China

The process to produce tert-butylhydroquinone from 2-tert-butyl phenol (2-TBP) is of great importance in the application of phenolic derivatives. However, the oxidation of 2-TBP to 2-tert-butyl-1,4-benzoquinone (2-TBQ) as the first step is usually performed in traditional batch reactors, suffering the disadvantages of mass transfer limitation and potential risk of explosion. Herein, a safer process to enhance the catalytic oxidation was developed by introducing gas-liquid segmented flow in a microchannel reactor. The 2-TBQ yield was approximately 70% within 29.02 min while the time was 8 h to obtained almost the same yield (65%) in batch systems. CFD simulation was conducted, confirming that secondary flow was formed in liquid slugs. The corresponding intensive convection ensured the con-tinuous and stable operation without particle sedimentation. On the basis of the enhanced mass transfer, the kinetics of 2-TBP oxidation was also investigated. The obtained reaction orders of 2-TBP and oxygen were 2.0948 and 0.4073, respectively. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： 2-TBP oxidation Kinetics segmented flow CFD simulation Heterogeneous catalysis

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Experimental and numerical studies of separation intensification in segmented flow microreactors

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CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION 2022年 176卷

作者： Zhang, Dong Cao, Ruimei Fu, Longyang Zhang, Yadong Zhengzhou Univ Sch Chem Engn Zhengzhou 450001 Peoples R China Zhengzhou Univ Ind Technol Sch Pharm & Chem Engn Zhengzhou 450001 Peoples R China Zhengzhou Univ Jiyuan Res Inst Jiyuan 459000 Peoples R China

Process intensification studies have already been well-established in continuous operations, particularly achieved by using microreactors. Separation intensification benefits from the application of process intensification and shows great potential, yet it is still not sufficiently studied. In this work, liquid-liquid two-phase segmented flow capillary microreactors and simulation models based on finite element method were used to perform experimental and numerical studies on the extractive separation intensification of the Zn-Cd-Mn system, respectively. The influence of hydrodynamics including metal ion concentration, plug velocity, and initial pH of the aqueous phase on the separation factor was explored. By regulating the hydrodynamic conditions, higher separation factors are obtained in shorter times to achieve separation intensification. The Damkhler number (Da) was introduced to clarify the rate-determining step and elaborate the separation mechanism. During the simulations, the results obtained from the model based on the finite element method agree well with the experimental ones. Taking advantage of the strong complementarity between numerical and experimental studies, separation intensification can be more deeply understood.

关键词： Separation intensification segmented flow Microreactor Numerical simulation

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Hydrodynamics and mass transfer in segmented flow small channel contactors for uranium extraction

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CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION 2020年 153卷

作者： Garciadiego-Ortega, Eduardo Tsaoulidis, Dimitrios Pineda, Miguel Fraga, Eric S. Angeli, Panagiota UCL Dept Chem Engn ThAMeS Multiphase London WC1E 7JE England

In this work, the extraction of U(VI) by tributyl phosphate (TBP) is studied in small channels of different sizes, operated in segmented flow. The variables analysed include the channel diameter (1-4 mm I.D.), mixture velocity (1.06 - 4.24 cm s(-1)), volume fraction of the continuous phase (between 0.200 and 0.500), and concentration of extractant (TBP 30% v/v in kerosene and TBP 100%). The hydrodynamic characteristics of the flow, such as plug and slug lengths, specific interfacial area, and dispersed phase holdup, were obtained experimentally using high-speed imaging, while the pressure drop was measured with a differential pressure transducer. These parameters were correlated to the studied variables. The concentration of uranium in the aqueous phase was measured with UV-vis spectroscopy, and the mass transfer coefficients were compared with the predictions of a numerical model of segmented flow developed in Comsol Multiphysics, with good agreement.

关键词： segmented flow Liquid-liquid extraction Interfacial mass transfer Pressure drop High-speed imaging

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Rapid Prostate Cancer Noninvasive Biomarker Screening Using segmented flow Mass Spectrometry-Based Untargeted Metabolomics

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JOURNAL OF PROTEOME RESEARCH 2020年第5期19卷 2080-2091页

作者： Pinto, Frederico G. Mahmud, Iqbal Harmon, Taylor A. Rubio, Vanessa Y. Garrett, Timothy J. Univ Florida Dept Pathol Immunol & Lab Med Clin & Translat Sci Inst Gainesville FL 32610 USA Univ Florida Southeast Ctr Integrated Metabol Clin & Translat Sci Inst Gainesville FL 32610 USA Univ Fed Vicosa Inst Ciencias Exatas & Tecnol BR-36570900 Vicosa MG Brazil Univ Florida Dept Chem Gainesville FL 32603 USA

Spectrometric methods with rapid biomarker detection capacity through untargeted metabolomics are becoming essential in the clinical cancer research. Liquid chromatography-mass spectrometry (LC-MS) is a rapidly developing metabolomic-based biomarker technique due to its high sensitivity, reproducibility, and separation efficiency. However, its translation to clinical diagnostics is often limited due to long data acquisition times (similar to 20 min/sample) and laborious sample extraction procedures when employed for large-scale metabolomics studies. Here, we developed a segmented flow approach coupled with high-resolution mass spectrometry (SF-HRMS) for untargeted metabolomics, which has the capability to acquire data in less than 1.5 min/sample with robustness and reproducibility relative to LC-HRMS. The SF-HRMS results demonstrate the capability for screening metabolite-based urinary biomarkers associated with prostate cancer (PCa). The study shows that SF-HRMS-based global metabolomics has the potential to evolve into a rapid biomarker screening tool for clinical research.

关键词： metabolomics segmented flow high-resolution mass spectrometry prostate cancer urine liquid biopsy noninvasive biomarker

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