Pub Date : 2022-11-03DOI: 10.3389/fceng.2022.1046627
G. Jang, Y. Zhang, J. Keum, Y. Bootwala, M. Hatzell, D. Jassby, C. Tsouris
In this work, neutron computed tomography (CT) is employed to investigate the dissolution of porous aluminum electrodes during electrocoagulation (EC). Porous electrodes were chosen in efforts to reduce electric power requirements by using larger surface-area electrodes, having both inner and outer surface, for the EC process. Neutron CT allowed 3D reconstruction of the porous electrodes, and image analysis provided the volume of each electrode vs. thickness, which can indicate whether the inner surface is effectively involved in EC reactions. For the anode, the volume decreased uniformly throughout the thickness of the electrode, indicating that both the outer and inner surface participated in electrochemical dissolution, while the volume of the cathode increased uniformly vs. thickness, indicating deposition of material on both the outer and inner surface. The attenuation coefficient vs. thickness, increased for both anode and cathode, indicating surface chemistry changes. For the anode, the attenuation coefficient increased slightly but uniformly, probably due to aluminum oxide formation on the surface of the anode. For the cathode, the attenuation coefficient increased more than for the anode and nonuniformly. The higher increase in the attenuation coefficient for the cathode is due to precipitation of aluminum hydroxide on the electrode surface, which added hydrogen. Image analysis also showed that, although the attenuation coefficient increased throughout the thickness of the electrode, most of the hydroxide deposition occurred on the outer surface. Energy analysis showed that porous electrodes can be used to reduce process energy requirements by as much as 4 times compared to solid electrodes.
{"title":"Neutron tomography of porous aluminum electrodes used in electrocoagulation of groundwater","authors":"G. Jang, Y. Zhang, J. Keum, Y. Bootwala, M. Hatzell, D. Jassby, C. Tsouris","doi":"10.3389/fceng.2022.1046627","DOIUrl":"https://doi.org/10.3389/fceng.2022.1046627","url":null,"abstract":"In this work, neutron computed tomography (CT) is employed to investigate the dissolution of porous aluminum electrodes during electrocoagulation (EC). Porous electrodes were chosen in efforts to reduce electric power requirements by using larger surface-area electrodes, having both inner and outer surface, for the EC process. Neutron CT allowed 3D reconstruction of the porous electrodes, and image analysis provided the volume of each electrode vs. thickness, which can indicate whether the inner surface is effectively involved in EC reactions. For the anode, the volume decreased uniformly throughout the thickness of the electrode, indicating that both the outer and inner surface participated in electrochemical dissolution, while the volume of the cathode increased uniformly vs. thickness, indicating deposition of material on both the outer and inner surface. The attenuation coefficient vs. thickness, increased for both anode and cathode, indicating surface chemistry changes. For the anode, the attenuation coefficient increased slightly but uniformly, probably due to aluminum oxide formation on the surface of the anode. For the cathode, the attenuation coefficient increased more than for the anode and nonuniformly. The higher increase in the attenuation coefficient for the cathode is due to precipitation of aluminum hydroxide on the electrode surface, which added hydrogen. Image analysis also showed that, although the attenuation coefficient increased throughout the thickness of the electrode, most of the hydroxide deposition occurred on the outer surface. Energy analysis showed that porous electrodes can be used to reduce process energy requirements by as much as 4 times compared to solid electrodes.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45043196","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}
Pub Date : 2022-11-03DOI: 10.3389/fceng.2022.838336
O. Tonomura, M. Noda, S. Hasebe
In the design of microreactors, the shape as well as the size is an important design factor for achieving high performance. Recent advances in computational fluid dynamics (CFD) enable us to know flow and temperature distributions in microreactors of various shapes and sizes without conducting experiments. However, it is often important to develop a simpler model than CFD to further reduce the computational time required for reactor design with iterative performance evaluations. In this research, a thermal-fluid compartment model-based approach is proposed for basic design of a multichannel microreactor. The proposed approach consists of two parts, i.e., thermal design and fluid design. In the thermal design part, two types of thermal compartments, which are used to discretize a reaction channel surrounded by wall and describe the mass and heat balances over the channel, are developed to optimize the channel shape. In the fluid design part, three types of fluid compartments, which are used to discretize the reactor and describe the mass and pressure balances over the reactor, are introduced to optimize manifold shape. The proposed approach is applied to a design problem and the results show that microchannels and manifolds with varying width are effective in realizing the uniform temperature and flow distributions, respectively. In addition to the proposed design approach, a transfer function-based compartment model is developed to estimate the residence time distribution of fluid in a microreactor without running time-dependent CFD simulation.
{"title":"Shape design of channels and manifolds in a multichannel microreactor using thermal-fluid compartment models","authors":"O. Tonomura, M. Noda, S. Hasebe","doi":"10.3389/fceng.2022.838336","DOIUrl":"https://doi.org/10.3389/fceng.2022.838336","url":null,"abstract":"In the design of microreactors, the shape as well as the size is an important design factor for achieving high performance. Recent advances in computational fluid dynamics (CFD) enable us to know flow and temperature distributions in microreactors of various shapes and sizes without conducting experiments. However, it is often important to develop a simpler model than CFD to further reduce the computational time required for reactor design with iterative performance evaluations. In this research, a thermal-fluid compartment model-based approach is proposed for basic design of a multichannel microreactor. The proposed approach consists of two parts, i.e., thermal design and fluid design. In the thermal design part, two types of thermal compartments, which are used to discretize a reaction channel surrounded by wall and describe the mass and heat balances over the channel, are developed to optimize the channel shape. In the fluid design part, three types of fluid compartments, which are used to discretize the reactor and describe the mass and pressure balances over the reactor, are introduced to optimize manifold shape. The proposed approach is applied to a design problem and the results show that microchannels and manifolds with varying width are effective in realizing the uniform temperature and flow distributions, respectively. In addition to the proposed design approach, a transfer function-based compartment model is developed to estimate the residence time distribution of fluid in a microreactor without running time-dependent CFD simulation.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46478767","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}
Pub Date : 2022-11-01DOI: 10.3389/fceng.2022.1059160
Kazem Adavi, A. Amini, M. Latifi, Jaber Shabanian, J. Chaouki
Microwave (MW) heating is rapid, selective, and volumetric, and it is a compelling non-conventional heating approach for driving chemical reactions. The effect of MW irradiation on the kinetics of thermal/catalytic reactions is still under debate. A group of researchers reported that the effect of MW heating on reaction kinetics is highlighted through the non-thermal effects of MWs on kinetic parameters and reaction mechanisms in addition to the thermal effect. However, another group attributed the observations to the thermal effect only. In the present work, we summarized and critically synthesized available information in the literature on the subject. It can be concluded that MW heating has solely the thermal effect on gas-solid reactions, and the variations of kinetic parameters are related to the direct and indirect impacts of that. Temperature measurement limitations, physical structure variation, and non-uniform temperature distribution are the primary sources of the discrepancy in previous studies. In ionic liquid-solid reactions, the presence of electromagnetic fields can affect the movement of ions/polar molecules which can be considered a non-thermal effect of MWs. However, the effect of MW absorption by solid/catalyst, and the formation of hot spots must be taken into account to avoid potential discrepancy. Therefore, further theoretical/experimental studies are required to clarify the effect of MWs on liquid-solid reactions. In addition, developing reliable temperature measurement methods and isothermal reaction domain are required for an accurate kinetic study during MW irradiation.
{"title":"Kinetic study of multiphase reactions under microwave irradiation: A mini-review","authors":"Kazem Adavi, A. Amini, M. Latifi, Jaber Shabanian, J. Chaouki","doi":"10.3389/fceng.2022.1059160","DOIUrl":"https://doi.org/10.3389/fceng.2022.1059160","url":null,"abstract":"Microwave (MW) heating is rapid, selective, and volumetric, and it is a compelling non-conventional heating approach for driving chemical reactions. The effect of MW irradiation on the kinetics of thermal/catalytic reactions is still under debate. A group of researchers reported that the effect of MW heating on reaction kinetics is highlighted through the non-thermal effects of MWs on kinetic parameters and reaction mechanisms in addition to the thermal effect. However, another group attributed the observations to the thermal effect only. In the present work, we summarized and critically synthesized available information in the literature on the subject. It can be concluded that MW heating has solely the thermal effect on gas-solid reactions, and the variations of kinetic parameters are related to the direct and indirect impacts of that. Temperature measurement limitations, physical structure variation, and non-uniform temperature distribution are the primary sources of the discrepancy in previous studies. In ionic liquid-solid reactions, the presence of electromagnetic fields can affect the movement of ions/polar molecules which can be considered a non-thermal effect of MWs. However, the effect of MW absorption by solid/catalyst, and the formation of hot spots must be taken into account to avoid potential discrepancy. Therefore, further theoretical/experimental studies are required to clarify the effect of MWs on liquid-solid reactions. In addition, developing reliable temperature measurement methods and isothermal reaction domain are required for an accurate kinetic study during MW irradiation.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42460140","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}
Pub Date : 2022-10-31DOI: 10.3389/fceng.2022.1012754
E. Ahmetovic, I. Grossmann, Z. Kravanja, François M. A. Maréchal, J. Klemeš, L. Savulescu, Hongguang Dong
Faculty of Technology, University of Tuzla, Tuzla, Bosnia and Herzegovina, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States, Faculty of Chemistry and Chemical Engineering, University of Maribor, Maribor, Slovenia, Swiss Federal Institute of Technology Lausanne, Lausanne, Switzerland, Sustainable Process Integration Laboratory—SPIL, NETME Centre, Faculty of Mechanical Engineering, Brno University of Technology—VUT BRNO, Brno, Czechia, CanmetENERGY, Natural Resources Canada, Varennes, QC, Canada, School of Chemical Engineering, Dalian University of Technology, Dalian, China
{"title":"Editorial: Combined water and heat integration in the process industries","authors":"E. Ahmetovic, I. Grossmann, Z. Kravanja, François M. A. Maréchal, J. Klemeš, L. Savulescu, Hongguang Dong","doi":"10.3389/fceng.2022.1012754","DOIUrl":"https://doi.org/10.3389/fceng.2022.1012754","url":null,"abstract":"Faculty of Technology, University of Tuzla, Tuzla, Bosnia and Herzegovina, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States, Faculty of Chemistry and Chemical Engineering, University of Maribor, Maribor, Slovenia, Swiss Federal Institute of Technology Lausanne, Lausanne, Switzerland, Sustainable Process Integration Laboratory—SPIL, NETME Centre, Faculty of Mechanical Engineering, Brno University of Technology—VUT BRNO, Brno, Czechia, CanmetENERGY, Natural Resources Canada, Varennes, QC, Canada, School of Chemical Engineering, Dalian University of Technology, Dalian, China","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41430869","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}
Pub Date : 2022-10-28DOI: 10.3389/fceng.2022.1056122
L. Chiang, M. Reis, Bo Shuang, Benben Jiang, Stéphanie Valleau
In the Industry 4.0 era, chemical process industry is embracing the broad adoption of Artificial Intelligence (AI) and Machine Learning (ML) methods and algorithms. This Research Topic aims to highlight state-of-the-art research in the fields of R&D, Manufacturing, and Supply Chain management. The papers demonstrate how AI/ML developments are contributing to speed up the product development cycle and how the industry is operating towards breakthrough performances in safety, reliability, and sustainability. The Research Topic is composed by four papers, covering different corners of the spectra of methodologies, processes and problems, as can be appreciated by the following short descriptions of each contribution. Webb et al., addressed the problem of exploring process databases to make robust diagnosis of the relevant modes, which can either be different operational conditions or faults. The authors explore dimensionality reduction (PCA, UMAP) and clustering methods (K-means, DBSCAN, and HDBSCAN). The article is therefore aligned with the current interest in exploiting data for improving process operations. In a similar application domain, Ma et al., demonstrated how nonlinear methods (such as LSTM neural networks) can integrate with linear methods (such as PCA) to optimize the decoking frequency in an industrial cracking furnace. The article is a testimony of successful AI and ML applications in manufacturing. In the scope of industrial process monitoring, Ji et al., designed and demonstrated a multiscale method based on time-frequency analysis (wavelet packet decomposition) and feature fusion (support vector data description). This work goes beyond the use of single scale features, OPEN ACCESS
{"title":"Editorial: Recent advances of AI and machine learning methods in integrated R&D, manufacturing, and supply chain","authors":"L. Chiang, M. Reis, Bo Shuang, Benben Jiang, Stéphanie Valleau","doi":"10.3389/fceng.2022.1056122","DOIUrl":"https://doi.org/10.3389/fceng.2022.1056122","url":null,"abstract":"In the Industry 4.0 era, chemical process industry is embracing the broad adoption of Artificial Intelligence (AI) and Machine Learning (ML) methods and algorithms. This Research Topic aims to highlight state-of-the-art research in the fields of R&D, Manufacturing, and Supply Chain management. The papers demonstrate how AI/ML developments are contributing to speed up the product development cycle and how the industry is operating towards breakthrough performances in safety, reliability, and sustainability. The Research Topic is composed by four papers, covering different corners of the spectra of methodologies, processes and problems, as can be appreciated by the following short descriptions of each contribution. Webb et al., addressed the problem of exploring process databases to make robust diagnosis of the relevant modes, which can either be different operational conditions or faults. The authors explore dimensionality reduction (PCA, UMAP) and clustering methods (K-means, DBSCAN, and HDBSCAN). The article is therefore aligned with the current interest in exploiting data for improving process operations. In a similar application domain, Ma et al., demonstrated how nonlinear methods (such as LSTM neural networks) can integrate with linear methods (such as PCA) to optimize the decoking frequency in an industrial cracking furnace. The article is a testimony of successful AI and ML applications in manufacturing. In the scope of industrial process monitoring, Ji et al., designed and demonstrated a multiscale method based on time-frequency analysis (wavelet packet decomposition) and feature fusion (support vector data description). This work goes beyond the use of single scale features, OPEN ACCESS","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42838087","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}
Pub Date : 2022-10-25DOI: 10.3389/fceng.2022.1000064
Tabea Stadler, Laila J. Bender, P. Pfeifer
This work presents the dynamic simulation of a novel sorption-enhanced water-gas shift reactor used for synthesis gas production from pure CO in an e-fuels synthesis process. Due to the intended decentralized plant installation associated with fluctuating feed, process intensification and a compact reactor system is required. An optimized operating procedure was obtained by simulation-driven process design to maximize the sorbent loading and operate the process as efficient as possible. The process simulation is based on a simplified heterogeneous packed bed reactor model. The model accounts for simultaneous water-gas shift (WGS) reaction on a Cu-based catalyst and CO2 adsorption on a K-impregnated hydrotalcite-derived mixed oxide as well as subsequent desorption. An empirical rate expression was chosen to describe the water-gas shift reaction according to experimental data at 250°C. Breakthrough experiments were performed and used to adapt kinetic adsorption (pressure: 8 bar) and desorption (pressure: 1 bar) parameters. The experimental CO2 sorption equilibrium isotherm was fitted with the Freundlich model. The reactor model was extended to a complex hybrid system scale model for the pilot plant reactor consisting of six individually accessible reaction chambers. Cyclic operation with automatized switching time adjustment was accomplished by a finite state machine. A case study exploited the benefits of a serial process configuration of reaction chambers. It could be shown that the sorbent loading can be remarkably increased through optimized operating strategies depending on the process conditions. Hence, the development of the hybrid model marks a crucial step towards the planned pilot plant operation and control.
{"title":"Dynamic simulation of a compact sorption-enhanced water-gas shift reactor","authors":"Tabea Stadler, Laila J. Bender, P. Pfeifer","doi":"10.3389/fceng.2022.1000064","DOIUrl":"https://doi.org/10.3389/fceng.2022.1000064","url":null,"abstract":"This work presents the dynamic simulation of a novel sorption-enhanced water-gas shift reactor used for synthesis gas production from pure CO in an e-fuels synthesis process. Due to the intended decentralized plant installation associated with fluctuating feed, process intensification and a compact reactor system is required. An optimized operating procedure was obtained by simulation-driven process design to maximize the sorbent loading and operate the process as efficient as possible. The process simulation is based on a simplified heterogeneous packed bed reactor model. The model accounts for simultaneous water-gas shift (WGS) reaction on a Cu-based catalyst and CO2 adsorption on a K-impregnated hydrotalcite-derived mixed oxide as well as subsequent desorption. An empirical rate expression was chosen to describe the water-gas shift reaction according to experimental data at 250°C. Breakthrough experiments were performed and used to adapt kinetic adsorption (pressure: 8 bar) and desorption (pressure: 1 bar) parameters. The experimental CO2 sorption equilibrium isotherm was fitted with the Freundlich model. The reactor model was extended to a complex hybrid system scale model for the pilot plant reactor consisting of six individually accessible reaction chambers. Cyclic operation with automatized switching time adjustment was accomplished by a finite state machine. A case study exploited the benefits of a serial process configuration of reaction chambers. It could be shown that the sorbent loading can be remarkably increased through optimized operating strategies depending on the process conditions. Hence, the development of the hybrid model marks a crucial step towards the planned pilot plant operation and control.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46141155","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}
Pub Date : 2022-10-20DOI: 10.3389/fceng.2022.1031395
Qiang Li, Ying Pan, Ling Han, Yakun Yang, Xinran Wu, Y. Lei
Human pluripotent stem cells (hPSCs) are ideal “raw materials” for making various human cell types for regenerative medicine and are needed in large numbers. 3D suspension culturing (e.g., stirred-tank bioreactor or STR), which suspends and cultures cells in an agitated medium, has been extensively studied to scale up hPSC production. However, a significant problem with 3D suspension is the uncontrolled spheroid agglomeration. It leads to cell growth arrest, cell apoptosis, and inhomogeneity in cell purity and quality. We propose that i) inhibiting the spheroid adhesion can prevent spheroid agglomeration and ii) the inhibition can be achieved via coating spheroids with biocompatible anti-adhesion molecules. We used PEG-lipids as model anti-adhesion molecules to successfully demonstrate the concept. PEG-lipids anchor to the spheroid surface through the interactions between their lipid chains and the cell membrane lipids. The flexible and hydrophilic PEG chains act as a dynamic barrier to prevent spheroid adhesion. We showed that the coating eliminated spheroid agglomeration, leading to homogenous spheroid size distribution and significant improvements in cell growth rate and volumetric yield. This novel approach is expected to impact large-scale hPSC production significantly. Furthermore, the approach can be generalized for culturing other human cell types.
{"title":"Improving three-dimensional human pluripotent cell culture efficiency via surface molecule coating","authors":"Qiang Li, Ying Pan, Ling Han, Yakun Yang, Xinran Wu, Y. Lei","doi":"10.3389/fceng.2022.1031395","DOIUrl":"https://doi.org/10.3389/fceng.2022.1031395","url":null,"abstract":"Human pluripotent stem cells (hPSCs) are ideal “raw materials” for making various human cell types for regenerative medicine and are needed in large numbers. 3D suspension culturing (e.g., stirred-tank bioreactor or STR), which suspends and cultures cells in an agitated medium, has been extensively studied to scale up hPSC production. However, a significant problem with 3D suspension is the uncontrolled spheroid agglomeration. It leads to cell growth arrest, cell apoptosis, and inhomogeneity in cell purity and quality. We propose that i) inhibiting the spheroid adhesion can prevent spheroid agglomeration and ii) the inhibition can be achieved via coating spheroids with biocompatible anti-adhesion molecules. We used PEG-lipids as model anti-adhesion molecules to successfully demonstrate the concept. PEG-lipids anchor to the spheroid surface through the interactions between their lipid chains and the cell membrane lipids. The flexible and hydrophilic PEG chains act as a dynamic barrier to prevent spheroid adhesion. We showed that the coating eliminated spheroid agglomeration, leading to homogenous spheroid size distribution and significant improvements in cell growth rate and volumetric yield. This novel approach is expected to impact large-scale hPSC production significantly. Furthermore, the approach can be generalized for culturing other human cell types.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49017950","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}
Pub Date : 2022-10-20DOI: 10.3389/fceng.2022.1021416
S. Seidel, R. Maschke, M. Kraume, R. Eibl, D. Eibl
Optimizing bioprocesses requires an in-depth understanding, from a bioengineering perspective, of the cultivation systems used. A bioengineering characterization is typically performed via experimental or numerical methods, which are particularly well-established for stirred bioreactors. For unstirred, non-rigid systems such as wave-mixed bioreactors, numerical methods prove to be problematic, as often only simplified geometries and motions can be assumed. In this work, a general approach for the numerical characterization of non-stirred cultivation systems is demonstrated using the CELL-tainer bioreactor with two degree of freedom motion as an example. In a first step, the motion is recorded via motion capturing, and a 3D model of the culture bag geometry is generated via 3D-scanning. Subsequently, the bioreactor is characterized with respect to mixing time, and oxygen transfer rate, as well as specific power input and temporal Kolmogorov length scale distribution. The results demonstrate that the CELL-tainer with two degrees of freedom outperforms classic wave-mixed bioreactors in terms of oxygen transport. In addition, it was shown that in the cell culture version of the CELL-tainer, the critical Kolmogorov length is not surpassed in any simulation.
{"title":"CFD modelling of a wave-mixed bioreactor with complex geometry and two degrees of freedom motion","authors":"S. Seidel, R. Maschke, M. Kraume, R. Eibl, D. Eibl","doi":"10.3389/fceng.2022.1021416","DOIUrl":"https://doi.org/10.3389/fceng.2022.1021416","url":null,"abstract":"Optimizing bioprocesses requires an in-depth understanding, from a bioengineering perspective, of the cultivation systems used. A bioengineering characterization is typically performed via experimental or numerical methods, which are particularly well-established for stirred bioreactors. For unstirred, non-rigid systems such as wave-mixed bioreactors, numerical methods prove to be problematic, as often only simplified geometries and motions can be assumed. In this work, a general approach for the numerical characterization of non-stirred cultivation systems is demonstrated using the CELL-tainer bioreactor with two degree of freedom motion as an example. In a first step, the motion is recorded via motion capturing, and a 3D model of the culture bag geometry is generated via 3D-scanning. Subsequently, the bioreactor is characterized with respect to mixing time, and oxygen transfer rate, as well as specific power input and temporal Kolmogorov length scale distribution. The results demonstrate that the CELL-tainer with two degrees of freedom outperforms classic wave-mixed bioreactors in terms of oxygen transport. In addition, it was shown that in the cell culture version of the CELL-tainer, the critical Kolmogorov length is not surpassed in any simulation.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41422555","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}
Pub Date : 2022-10-20DOI: 10.3389/fceng.2022.883502
Shuo Wang, Xinbin Wu, Yuhan Liang, Yushuai Xu, Shundong Guan, Kaihua Wen, Xiang Miao, Ying Liang, H. He, Yuanhua Lin, Yang Shen, C. Nan
Bromine-rich lithium argyrodite electrolytes with high ionic conductivity and low cost are promising for the replacement of flammable liquid electrolytes and separators in lithium-ion batteries. However, the synthesis process of argyrodite electrolytes is usually complex and time-consuming. We use a facile solid-state reaction method to obtain a highly Li-ion conductive Li5.5PS4.5Br1.5 (LPSB). The influence of annealing temperature on the phase and ionic conductivity of the LPSB was investigated for the first time. High ionic conductivity of 5.21 × 10−3 S cm−1 at room temperature for the LPSB with minor LiBr impurity was achieved by direct annealing at 430°C for 8 h. The In/InLi | LPSB | LiCoO2@ LiNb0.5Ta0.5O3 (LCO(coated))-LPSB cell with 8.53 mg cm−2 LCO loading shows a discharge capacity of 102 mAh g−1 with high-capacity retention of 93% after 70 cycles at 0.5 mA cm−2 at 30°C.
富含溴的高离子导电性、低成本的亚硝酸锂电解质有望取代锂离子电池中的易燃液体电解质和隔膜。然而，银石电解质的合成过程通常是复杂和耗时的。我们使用简单的固态反应方法获得了高Li离子传导性的Li5.5PS4.5Br1.5（LPSB）。首次研究了退火温度对LPSB相和离子电导率的影响。具有少量LiBr杂质的LPSB在室温下通过在430°C下直接退火8小时获得5.21×10−3 S cm−1的高离子电导率。具有8.53 mg cm−2 LCO负载的In/InLi|LPSB|LiCoO2@LiNb0.5Ta0.5O3（LCO（涂层））-LPSB电池在30°C下0.5 mA cm−2下70次循环后显示出102 mAh g−1的放电容量和93%的高容量保持率。
{"title":"Facile synthesis of lithium argyrodite Li5.5PS4.5Br1.5 with high ionic conductivity for all-solid-state batteries","authors":"Shuo Wang, Xinbin Wu, Yuhan Liang, Yushuai Xu, Shundong Guan, Kaihua Wen, Xiang Miao, Ying Liang, H. He, Yuanhua Lin, Yang Shen, C. Nan","doi":"10.3389/fceng.2022.883502","DOIUrl":"https://doi.org/10.3389/fceng.2022.883502","url":null,"abstract":"Bromine-rich lithium argyrodite electrolytes with high ionic conductivity and low cost are promising for the replacement of flammable liquid electrolytes and separators in lithium-ion batteries. However, the synthesis process of argyrodite electrolytes is usually complex and time-consuming. We use a facile solid-state reaction method to obtain a highly Li-ion conductive Li5.5PS4.5Br1.5 (LPSB). The influence of annealing temperature on the phase and ionic conductivity of the LPSB was investigated for the first time. High ionic conductivity of 5.21 × 10−3 S cm−1 at room temperature for the LPSB with minor LiBr impurity was achieved by direct annealing at 430°C for 8 h. The In/InLi | LPSB | LiCoO2@ LiNb0.5Ta0.5O3 (LCO(coated))-LPSB cell with 8.53 mg cm−2 LCO loading shows a discharge capacity of 102 mAh g−1 with high-capacity retention of 93% after 70 cycles at 0.5 mA cm−2 at 30°C.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43201455","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}
Pub Date : 2022-10-19DOI: 10.3389/fceng.2022.1035348
A. Beugholt, K. Büchner, D. Geier, T. Becker
When confronted with environmental stress, yeast cell reacts, among others, by modifying the expression of specific genes. In this study, gene expression was analyzed via RT-qPCR to quantify the oxidative stress of Saccharomyces pastorianus during yeast propagation as a reaction to different aeration levels. Target genes were identified, and a reference gene system was developed. Fermentation experiments were conducted in shaking flasks, applying different shaking speeds to generate various aeration efficiencies. The cells were sampled at different propagation stages and, additionally to the expression study, analyzed by flow cytometry after staining with dihydroethidium (DHE) to quantify reactive oxygen species (ROS) inside the cells. The results indicate that high oxygen fermentation conditions led to an increased expression of the catalase-A gene CTA1 during propagation. Furthermore, the determination of cell internal ROS shows increasing oxidative stress over the process in accordance with the RT-qPCR measurements.
{"title":"Quantification of oxidative stress in Saccharomyces pastorianus propagation: Gene expression analysis using quantitative reverse transcription polymerase chain reaction and flow cytometry","authors":"A. Beugholt, K. Büchner, D. Geier, T. Becker","doi":"10.3389/fceng.2022.1035348","DOIUrl":"https://doi.org/10.3389/fceng.2022.1035348","url":null,"abstract":"When confronted with environmental stress, yeast cell reacts, among others, by modifying the expression of specific genes. In this study, gene expression was analyzed via RT-qPCR to quantify the oxidative stress of Saccharomyces pastorianus during yeast propagation as a reaction to different aeration levels. Target genes were identified, and a reference gene system was developed. Fermentation experiments were conducted in shaking flasks, applying different shaking speeds to generate various aeration efficiencies. The cells were sampled at different propagation stages and, additionally to the expression study, analyzed by flow cytometry after staining with dihydroethidium (DHE) to quantify reactive oxygen species (ROS) inside the cells. The results indicate that high oxygen fermentation conditions led to an increased expression of the catalase-A gene CTA1 during propagation. Furthermore, the determination of cell internal ROS shows increasing oxidative stress over the process in accordance with the RT-qPCR measurements.","PeriodicalId":73073,"journal":{"name":"Frontiers in chemical engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42297275","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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