Ivan Pokatilov, Valentina Gritsenko, Alexey Zhokh, Peter Strizhak
ZSM-5/γ-Al2O3 composites are synthesized using multiwall carbon nanotubes as a pore-forming agent. The as-prepared composites are characterized by nitrogen adsorption, X-ray diffraction, X-ray fluorescence, TEM, SEM, FT-IR spectroscopy, and pyridine adsorption. The as-prepared composites exhibit significantly different physicochemical properties depending on the synthesis technique. The catalytic activity of the as-prepared composites toward methanol dehydration to dimethyl ether is investigated. The as-prepared composites demonstrate the methanol conversion close to the equilibrium one with 100% selectivity toward dimethyl ether. The kinetic parameters of the process are measured highlighting the effect of the textural and acidic properties of the composites on their catalytic performance.
{"title":"ZSM-5/γ-Al2O3 Catalysts for Methanol Dehydration: Tuning Pore Structure by Carbon Nanotubes as a Pore-Forming Agent","authors":"Ivan Pokatilov, Valentina Gritsenko, Alexey Zhokh, Peter Strizhak","doi":"10.1155/2023/6629794","DOIUrl":"https://doi.org/10.1155/2023/6629794","url":null,"abstract":"ZSM-5/<i>γ</i>-Al<sub>2</sub>O<sub>3</sub> composites are synthesized using multiwall carbon nanotubes as a pore-forming agent. The as-prepared composites are characterized by nitrogen adsorption, X-ray diffraction, X-ray fluorescence, TEM, SEM, FT-IR spectroscopy, and pyridine adsorption. The as-prepared composites exhibit significantly different physicochemical properties depending on the synthesis technique. The catalytic activity of the as-prepared composites toward methanol dehydration to dimethyl ether is investigated. The as-prepared composites demonstrate the methanol conversion close to the equilibrium one with 100% selectivity toward dimethyl ether. The kinetic parameters of the process are measured highlighting the effect of the textural and acidic properties of the composites on their catalytic performance.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"97 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139054389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The finned-tube heat exchanger is the core part of an air conditioning system. Its heat exchange performance directly affects the energy consumption and efficiency of the air conditioner. The shortage and rising price of copper have led to increasing replacement of copper tubes with aluminum tubes in finned-tube heat exchangers. This paper studies two kinds of such heat exchangers, one consisting of copper tubes and aluminum fins and the other consisting of aluminum tubes and aluminum fins. The influences of the different base tube materials on heat transfer are compared and analyzed in terms of heat transfer strength and cost per unit heat transfer. The results show that the heat transfer and heat transfer coefficient increase with increasing inlet wind speed. Under different inlet wind speeds, the heat transfer and heat transfer coefficient of the finned-tube heat exchanger with aluminum tubes are 4%–12% and 7%%–9% lower than those of an identically structured heat exchanger with copper tubes, respectively. The aluminum-aluminum exchanger achieves 67% higher heat transfer than that of the copper-aluminum exchanger at only 8% of the cost. These results are significant for guiding the development and application of finned-tube heat exchangers.
{"title":"Comprehensive Evaluation of the Performances of Heat Exchangers with Aluminum and Copper Finned Tubes","authors":"Fang Wang, Yunding Li, Mengwei Liu, Dongqing Pang, Weifeng Du, Yichi Zhang, Xiaoqian Cheng, Tangtang Gu, Wenliang Guo","doi":"10.1155/2023/6666947","DOIUrl":"https://doi.org/10.1155/2023/6666947","url":null,"abstract":"The finned-tube heat exchanger is the core part of an air conditioning system. Its heat exchange performance directly affects the energy consumption and efficiency of the air conditioner. The shortage and rising price of copper have led to increasing replacement of copper tubes with aluminum tubes in finned-tube heat exchangers. This paper studies two kinds of such heat exchangers, one consisting of copper tubes and aluminum fins and the other consisting of aluminum tubes and aluminum fins. The influences of the different base tube materials on heat transfer are compared and analyzed in terms of heat transfer strength and cost per unit heat transfer. The results show that the heat transfer and heat transfer coefficient increase with increasing inlet wind speed. Under different inlet wind speeds, the heat transfer and heat transfer coefficient of the finned-tube heat exchanger with aluminum tubes are 4%–12% and 7%%–9% lower than those of an identically structured heat exchanger with copper tubes, respectively. The aluminum-aluminum exchanger achieves 67% higher heat transfer than that of the copper-aluminum exchanger at only 8% of the cost. These results are significant for guiding the development and application of finned-tube heat exchangers.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"73 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138820587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nazar Oudah Mousa Alyaseen, Salem Mehrzad, Mohammad Reza Saffarian
Recent years have seen considerable advancement in cryogenic technology. Air separation devices have used the cold box with heat exchanger plate-fin (PFHE) in numerous applications. Cryogenic technologies are used in many industrial processes to recover heat and reduce energy consumption. The multistream plate-fin heat exchanger (MSPFHE) is heavily utilized in the air separation plant’s (ASU) design. The plate-fin heat exchanger, one of the most important applications in the cryogenic industry, is the focus of the current investigation. The air entering this operation has been cooled by utilizing energy from streams originating from the distillation tower in the air separation unit (ASU) to reduce energy usage. The project aims to develop and create a multistream plate-fin heat exchanger (MSPFHE) that may be used in the cold box of an air separation unit practically and without limitations. The pinch technique, a method based on the usage of composite curves, was used in the creation of MSPFHE. With pinch technology, it is possible to divide a multistream exchanger into block portions that represent enthalpy intervals and identify the entry and departure sites for the streams. The correlations used in the MSPFHE thermal design model were first modeled and compared to earlier models as part of this effort. This model has been turned into MATLAB code and utilized in two case studies to yield acceptable results during the sizing step. Calculations of thermodynamic properties, heat transfer, pressure drop, choice of fin type, and final heat exchanger size were all part of the design of the MSPFHE. Finally, based on the software’s ability to reproduce the identical environmental conditions nature produces, the case study results have been validated using Aspen EDR. These findings were matched to findings from the literature and determined to be reliable and consistent.
{"title":"Modeling and Design of a Multistream Plate-Fin Heat Exchanger in the Air Separation Units by Pinch Technology","authors":"Nazar Oudah Mousa Alyaseen, Salem Mehrzad, Mohammad Reza Saffarian","doi":"10.1155/2023/9204268","DOIUrl":"https://doi.org/10.1155/2023/9204268","url":null,"abstract":"Recent years have seen considerable advancement in cryogenic technology. Air separation devices have used the cold box with heat exchanger plate-fin (PFHE) in numerous applications. Cryogenic technologies are used in many industrial processes to recover heat and reduce energy consumption. The multistream plate-fin heat exchanger (MSPFHE) is heavily utilized in the air separation plant’s (ASU) design. The plate-fin heat exchanger, one of the most important applications in the cryogenic industry, is the focus of the current investigation. The air entering this operation has been cooled by utilizing energy from streams originating from the distillation tower in the air separation unit (ASU) to reduce energy usage. The project aims to develop and create a multistream plate-fin heat exchanger (MSPFHE) that may be used in the cold box of an air separation unit practically and without limitations. The pinch technique, a method based on the usage of composite curves, was used in the creation of MSPFHE. With pinch technology, it is possible to divide a multistream exchanger into block portions that represent enthalpy intervals and identify the entry and departure sites for the streams. The correlations used in the MSPFHE thermal design model were first modeled and compared to earlier models as part of this effort. This model has been turned into MATLAB code and utilized in two case studies to yield acceptable results during the sizing step. Calculations of thermodynamic properties, heat transfer, pressure drop, choice of fin type, and final heat exchanger size were all part of the design of the MSPFHE. Finally, based on the software’s ability to reproduce the identical environmental conditions nature produces, the case study results have been validated using Aspen EDR. These findings were matched to findings from the literature and determined to be reliable and consistent.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"70 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study examined the phenomenon of particle segregation in lean-phase binary mixtures, with a specific focus on the effect of particle size variations while flowing over a continuous liquid fluidized bed (LFB). The experimental configuration included a cylindrical column with a 72 mm internal diameter and 3 m vertical height. The binary mixture considered for this investigation was made up of solid materials that were rich in flotsam and jetsam. The study encompassed various factors, including liquid velocity, solid feed rate, and feed composition, in order to examine the separations containing flotsam and jetsam. A segregation index was calculated for each of the various combinations. On the other hand, the fluidization of the blend consisting of two solid components displayed notable differences in its behavior when compared to the reported effects of particle separation in any of the mixtures. Empirical correlations have been employed to establish relationships between variables, particularly with respect to solid entrainment and top and bottom product purity levels.
{"title":"An Experimental Analysis of Lean Binary Mixture Segregation in a Continuous Liquid Fluidized Bed","authors":"S. Narasimha Reddy, M. Venkata Ratnam","doi":"10.1155/2023/7756174","DOIUrl":"https://doi.org/10.1155/2023/7756174","url":null,"abstract":"This study examined the phenomenon of particle segregation in lean-phase binary mixtures, with a specific focus on the effect of particle size variations while flowing over a continuous liquid fluidized bed (LFB). The experimental configuration included a cylindrical column with a 72 mm internal diameter and 3 m vertical height. The binary mixture considered for this investigation was made up of solid materials that were rich in flotsam and jetsam. The study encompassed various factors, including liquid velocity, solid feed rate, and feed composition, in order to examine the separations containing flotsam and jetsam. A segregation index was calculated for each of the various combinations. On the other hand, the fluidization of the blend consisting of two solid components displayed notable differences in its behavior when compared to the reported effects of particle separation in any of the mixtures. Empirical correlations have been employed to establish relationships between variables, particularly with respect to solid entrainment and top and bottom product purity levels.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135291407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Milan Phuyal, Uttam Budhathoki, Durga Bista, Shailendra Shakya, Rajan Shrestha, Ashwinee Kumar Shrestha
The present study is focused on the availability of microbial sources capable of producing xylanase, a hemicelluloses-degrading enzyme with multiple modes of action along with specificity, and their real-world applications. For the accumulation of suitable data, article surfing was carried out using multiple search engines viz. Hinari and PubMed; irrelevant and duplicate articles were discarded and articles were summarized in a narrative way herein. This review article was written aiming to bridge the recent research activities with the commercial activities of xylanase going on around the globe. The readers would be able to acknowledge themselves with the basic idea of the hydrolytic enzyme xylanase, their classification representing their different families, presenting the affinity of different families at the structural level, the sources, and the commercial implications that have been going on alone and in combination. The major hemicellulose, Xylan is digested with the help of combination other enzymes such as alpha-amylase, subtilisin, protease, and endo-1,3(4)-β-glucanase along with xylanase. Xylanase has a diverse applications such as pharmaceutical, food and feed, bakery, paper and pulp, textile, and bio-refinery industries. The objective of this review article is to compile microbial sources of this enzyme and its application for betterment of human kind.
{"title":"Xylanase-Producing Microbes and Their Real-World Application","authors":"Milan Phuyal, Uttam Budhathoki, Durga Bista, Shailendra Shakya, Rajan Shrestha, Ashwinee Kumar Shrestha","doi":"10.1155/2023/3593035","DOIUrl":"https://doi.org/10.1155/2023/3593035","url":null,"abstract":"The present study is focused on the availability of microbial sources capable of producing xylanase, a hemicelluloses-degrading enzyme with multiple modes of action along with specificity, and their real-world applications. For the accumulation of suitable data, article surfing was carried out using multiple search engines viz. Hinari and PubMed; irrelevant and duplicate articles were discarded and articles were summarized in a narrative way herein. This review article was written aiming to bridge the recent research activities with the commercial activities of xylanase going on around the globe. The readers would be able to acknowledge themselves with the basic idea of the hydrolytic enzyme xylanase, their classification representing their different families, presenting the affinity of different families at the structural level, the sources, and the commercial implications that have been going on alone and in combination. The major hemicellulose, Xylan is digested with the help of combination other enzymes such as alpha-amylase, subtilisin, protease, and endo-1,3(4)-β-glucanase along with xylanase. Xylanase has a diverse applications such as pharmaceutical, food and feed, bakery, paper and pulp, textile, and bio-refinery industries. The objective of this review article is to compile microbial sources of this enzyme and its application for betterment of human kind.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"61 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135221135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marcell S. Deus, Katherine C. O. Deus, Daniel S. Lira, Jackson A. Oliveira, Carlos E. A. Padilha, Domingos F. S. Souza
Although biodiesel production is undoubtedly a mature technology, there are still ways to improve it, especially through process intensification. The present study investigated the esterification of oleic acid with ethanol for biodiesel production in a nonconventional atomization reactor. The effects of the oleic acid flow rate (1.3, 2.6, and 3.9 g/min), atomization pressure (50, 100, and 150 kPa), and temperature (323, 333, and 343 K) were evaluated by a complete factorial experimental design. The size of droplets was determined by computational image processing. A mathematical model was also developed to describe the conversion of oleic acid to ethyl ester as a function of molar concentration of components and operating conditions of the reactor. A hybrid estimation of parameters (pre-exponential factor, activation energy, and equilibrium and solubility constants) was performed using particle swarm optimization followed by the Broyden–Fletcher–Goldfarb–Shanno method. The Pareto analysis has shown that the increase in temperature in the reactor and the increase in atomization pressure have improved the conversion of oleic acid. Higher pressure values in the atomization nozzle led to the generation of small oleic acid droplets, which accelerated reagent consumption during the reaction. On the other hand, conversion values were reduced by increasing the oleic acid flow rate. The highest conversion of oleic acid (86.7%) was obtained under the following reaction conditions: temperature of 343 K, atomization pressure of 150 kPa, oleic acid flow rate equal to 1.3 g/min using 0.7% sulfuric acid (mol of sulfuric acid/mol of oleic acid), and 2 h of reaction time. The simulations showed that esterification is governed by temperature, but it is possible to observe that the atomization pressure affects more conversion of oleic acid under a low temperature (<323 K).
{"title":"Esterification of Oleic Acid for Biodiesel Production Using a Semibatch Atomization Apparatus","authors":"Marcell S. Deus, Katherine C. O. Deus, Daniel S. Lira, Jackson A. Oliveira, Carlos E. A. Padilha, Domingos F. S. Souza","doi":"10.1155/2023/6957812","DOIUrl":"https://doi.org/10.1155/2023/6957812","url":null,"abstract":"Although biodiesel production is undoubtedly a mature technology, there are still ways to improve it, especially through process intensification. The present study investigated the esterification of oleic acid with ethanol for biodiesel production in a nonconventional atomization reactor. The effects of the oleic acid flow rate (1.3, 2.6, and 3.9 g/min), atomization pressure (50, 100, and 150 kPa), and temperature (323, 333, and 343 K) were evaluated by a complete factorial experimental design. The size of droplets was determined by computational image processing. A mathematical model was also developed to describe the conversion of oleic acid to ethyl ester as a function of molar concentration of components and operating conditions of the reactor. A hybrid estimation of parameters (pre-exponential factor, activation energy, and equilibrium and solubility constants) was performed using particle swarm optimization followed by the Broyden–Fletcher–Goldfarb–Shanno method. The Pareto analysis has shown that the increase in temperature in the reactor and the increase in atomization pressure have improved the conversion of oleic acid. Higher pressure values in the atomization nozzle led to the generation of small oleic acid droplets, which accelerated reagent consumption during the reaction. On the other hand, conversion values were reduced by increasing the oleic acid flow rate. The highest conversion of oleic acid (86.7%) was obtained under the following reaction conditions: temperature of 343 K, atomization pressure of 150 kPa, oleic acid flow rate equal to 1.3 g/min using 0.7% sulfuric acid (mol of sulfuric acid/mol of oleic acid), and 2 h of reaction time. The simulations showed that esterification is governed by temperature, but it is possible to observe that the atomization pressure affects more conversion of oleic acid under a low temperature (<323 K).","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"800 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136019435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multiphase flows and mixing in partially filled conveying elements of twin-screw extruders (TSEs) were simulated by using smoothed-particle hydrodynamics (SPH). A validation of SPH using experiment from the literature for a co-rotating twin-cam mixer indicated good agreement. A two-phase Poiseuille flow was also used to validate the accuracy of our approach. The results of two-phase flow in TSE show that the viscosity ratio significantly affects the flow and mixing of two-phase fluids. The symmetry of flow field is broken with different parameters. In the full filled case, the pressure squeezes particles into the gap, which is conducive to improve the performance of mixing of fluids. On the contrary, in the partially filled case, because there is no background pressure, particles tend to bypass the gap and flow to the cavity of the chamber. This work laid a foundation for further study of polymer blending by simulation.
{"title":"Simulation of Multiphase Flow and Mixing in a Conveying Element of a Co-Rotating Twin-Screw Extruder by Using SPH","authors":"Tianwen Dong, Jianchun Wu, Yufei Ruan, Jiawen Huang, Shiyu Jiang","doi":"10.1155/2023/8383763","DOIUrl":"https://doi.org/10.1155/2023/8383763","url":null,"abstract":"Multiphase flows and mixing in partially filled conveying elements of twin-screw extruders (TSEs) were simulated by using smoothed-particle hydrodynamics (SPH). A validation of SPH using experiment from the literature for a co-rotating twin-cam mixer indicated good agreement. A two-phase Poiseuille flow was also used to validate the accuracy of our approach. The results of two-phase flow in TSE show that the viscosity ratio significantly affects the flow and mixing of two-phase fluids. The symmetry of flow field is broken with different parameters. In the full filled case, the pressure squeezes particles into the gap, which is conducive to improve the performance of mixing of fluids. On the contrary, in the partially filled case, because there is no background pressure, particles tend to bypass the gap and flow to the cavity of the chamber. This work laid a foundation for further study of polymer blending by simulation.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"19 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Retracted: Photocatalytic Performance Study of Organophosphorus-Doped Tungsten Trioxide and Composite Materials","authors":"International Journal of Chemical Engineering","doi":"10.1155/2023/9826309","DOIUrl":"https://doi.org/10.1155/2023/9826309","url":null,"abstract":"<jats:p />","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper addresses the problem of parameter estimation for the microbial continuous fermentation of glycerol to 1,3-propanediol. A nonlinear dynamical system is first presented to describe the microbial continuous fermentation. Some mathematical properties of the dynamical system in the microbial continuous fermentation are also presented. A parameter estimation model is proposed to estimate the parameters of the dynamical system. The proposed estimation model is a large-scale, nonlinear, and nonconvex optimization problem if the number of experimental groups is large. A sequential geometric programming (SGP) method is proposed to efficiently solve the parameter estimation problem. The results indicated that our proposed SGP method can yield smaller errors between the experimental and calculated steady-state concentrations than the existing seven methods. For the five error indices considered, that is, the concentration errors of biomass, glycerol, 1,3-propanediol, acetic acid, and ethanol, the results obtained using the proposed SGP method are better than those obtained using the methods in the literature (Xiu et al., Gao et al., Sun et al., Sun et al., Li and Qu, Wang et al., and Zhang and Xu), with improvements of approximately 71.86–95.03%, 52.08–94.87%, 99.70–99.98%, 5.39–90.29%, and 12.67–80.83%, respectively. This concludes that the established dynamical system can better describe the microbial continuous fermentation. We also present that our established dynamical system has multiple positive steady states in some fermentation conditions. We observe that there are two regions of multiple positive steady states at relatively high values of substrate glycerol concentration in feed medium.
研究了微生物连续发酵甘油制1,3-丙二醇的参数估计问题。首次提出了描述微生物连续发酵过程的非线性动力系统。给出了微生物连续发酵过程中动力系统的一些数学性质。提出了一种参数估计模型来估计动力系统的参数。所提出的估计模型是一个大规模的、非线性的、非凸的优化问题。为了有效地解决参数估计问题，提出了序列几何规划(SGP)方法。结果表明，与现有的7种方法相比，我们提出的SGP方法在实验和计算稳态浓度之间的误差更小。对于生物质、甘油、1,3-丙二醇、乙酸、乙醇等5个误差指标，采用SGP方法得到的结果优于文献方法(Xiu et al.、Gao et al.、Sun et al.、Sun et al.、Li and Qu .、Wang et al.、Zhang and Xu .)，分别提高了约71.86-95.03%、52.08-94.87%、99.70-99.98%、5.39-90.29%和12.67-80.83%。由此可见，所建立的动力学系统能较好地描述微生物连续发酵过程。我们还证明了所建立的动力系统在某些发酵条件下具有多个正稳态。我们观察到，在饲料培养基中相对较高的底物甘油浓度值下，有两个区域存在多个正稳态。
{"title":"Sequential Geometric Programming Method for Parameter Estimation of a Nonlinear System in Microbial Continuous Fermentation","authors":"Gongxian Xu, Zijia Liu","doi":"10.1155/2023/8072920","DOIUrl":"https://doi.org/10.1155/2023/8072920","url":null,"abstract":"This paper addresses the problem of parameter estimation for the microbial continuous fermentation of glycerol to 1,3-propanediol. A nonlinear dynamical system is first presented to describe the microbial continuous fermentation. Some mathematical properties of the dynamical system in the microbial continuous fermentation are also presented. A parameter estimation model is proposed to estimate the parameters of the dynamical system. The proposed estimation model is a large-scale, nonlinear, and nonconvex optimization problem if the number of experimental groups is large. A sequential geometric programming (SGP) method is proposed to efficiently solve the parameter estimation problem. The results indicated that our proposed SGP method can yield smaller errors between the experimental and calculated steady-state concentrations than the existing seven methods. For the five error indices considered, that is, the concentration errors of biomass, glycerol, 1,3-propanediol, acetic acid, and ethanol, the results obtained using the proposed SGP method are better than those obtained using the methods in the literature (Xiu et al., Gao et al., Sun et al., Sun et al., Li and Qu, Wang et al., and Zhang and Xu), with improvements of approximately 71.86–95.03%, 52.08–94.87%, 99.70–99.98%, 5.39–90.29%, and 12.67–80.83%, respectively. This concludes that the established dynamical system can better describe the microbial continuous fermentation. We also present that our established dynamical system has multiple positive steady states in some fermentation conditions. We observe that there are two regions of multiple positive steady states at relatively high values of substrate glycerol concentration in feed medium.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"223 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136294045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yefan Wang, Shan Gao, Haoying Li, Yang Cao, Yijie Zhai, Niezheng Chen, Zequn Yang
A critical challenge that impedes the application of photocatalytic techniques for organic dye degradation from polluted industrial effluents is that traditional powdery photocatalysts exposed limited photo-absorption sites and exhibited inefficient recyclability. To overcome these challenges, this study designed a one-step process to synthesize a monolithic copper selenide (CuSe)-based photocatalyst. The characterization results fully supported that the maintenance of the copper foam during the selenization process was the prerequisite for the monolithic photocatalyst to keep its structural integrity in photocatalytic reactions. The surface of the monolithic photocatalyst fully covered by active CuSe is crucial for the exposure of photocatalytically active sites and the efficient degradation of methylene blue (MB). It was found that the CuSe-based monolithic photocatalyst exhibited excellent MB degradation performances under harsh pH conditions and high MB concentrations. From these perspectives, it is reasonable to conclude that the CuSe-based monolithic photocatalyst as prepared is a promising alternative to traditional powdery photocatalysts for organic dye degradation and industrial effluent cleaning.
{"title":"Copper Selenide (CuSe) Monolith Fabricated by Facile Copper Foam Selenization for Efficient Photocatalytic Degradation of Methylene Blue","authors":"Yefan Wang, Shan Gao, Haoying Li, Yang Cao, Yijie Zhai, Niezheng Chen, Zequn Yang","doi":"10.1155/2023/2360674","DOIUrl":"https://doi.org/10.1155/2023/2360674","url":null,"abstract":"A critical challenge that impedes the application of photocatalytic techniques for organic dye degradation from polluted industrial effluents is that traditional powdery photocatalysts exposed limited photo-absorption sites and exhibited inefficient recyclability. To overcome these challenges, this study designed a one-step process to synthesize a monolithic copper selenide (CuSe)-based photocatalyst. The characterization results fully supported that the maintenance of the copper foam during the selenization process was the prerequisite for the monolithic photocatalyst to keep its structural integrity in photocatalytic reactions. The surface of the monolithic photocatalyst fully covered by active CuSe is crucial for the exposure of photocatalytically active sites and the efficient degradation of methylene blue (MB). It was found that the CuSe-based monolithic photocatalyst exhibited excellent MB degradation performances under harsh pH conditions and high MB concentrations. From these perspectives, it is reasonable to conclude that the CuSe-based monolithic photocatalyst as prepared is a promising alternative to traditional powdery photocatalysts for organic dye degradation and industrial effluent cleaning.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134885944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：