Long Ding, Hexi Zhao, Yafei Li, Yi-fan Wang, Hongming Long
The challenges posed by volatile organic compound (VOC) emissions in iron ore sintering flue gas are significant. La-based perovskite catalysts offer a promising solution for efficiently degrading VOCs. In this study, a series of LaBO3 (B = Cu, Fe, Cr, Mn, Co) perovskite catalysts were synthesized using the sol-gel method. The influence of various B-site elements on the catalyst’s structure and surface chemical properties was thoroughly examined. Simulations were conducted to assess the VOC reduction capabilities of these catalysts under conditions mimicking sintering flue gas composition. It was found that the crystallite size of the perovskite catalyst decreases as the ionic radius of the B-site elements increases, while the specific surface area, total pore volume, and average pore size increase correspondingly. Notably, LaCoO3 and LaMnO3 demonstrated exceptional activity, attributed primarily to their elevated surface oxygen concentration and oxygen migration capability, positioning them as highly promising materials for further development. Furthermore, a proposed mechanism elucidates the La-based perovskite catalytic reduction of toluene, wherein lattice oxygen and adsorbed oxygen undergo mutual conversion during the oxidation process. This mechanism aligns with the L-H and M-v-K models, providing a comprehensive understanding of the catalytic process.
铁矿烧结烟气中的挥发性有机化合物（VOC）排放带来了巨大挑战。La 基包晶催化剂为有效降解挥发性有机化合物提供了一种前景广阔的解决方案。本研究采用溶胶-凝胶法合成了一系列 LaBO3（B = Cu、Fe、Cr、Mn、Co）包晶催化剂。研究深入考察了各种 B 位元素对催化剂结构和表面化学性质的影响。在模拟烧结烟气成分的条件下，对这些催化剂的挥发性有机化合物还原能力进行了模拟评估。研究发现，随着 B 位元素离子半径的增大，过氧化物催化剂的结晶尺寸减小，而比表面积、总孔体积和平均孔尺寸则相应增大。值得注意的是，LaCoO3 和 LaMnO3 表现出了优异的活性，这主要归功于它们较高的表面氧浓度和氧迁移能力，使它们成为极有潜力进一步开发的材料。此外，还提出了一种机制，阐明了 La 基包晶石催化还原甲苯的机制，其中晶格氧和吸附氧在氧化过程中发生了相互转化。该机理与 L-H 和 M-v-K 模型相吻合，为催化过程提供了全面的理解。
{"title":"VOCs (toluene) removal from iron ore sintering flue gas via LaBO3 (B = Cu, Fe, Cr, Mn, Co) perovskite catalysts: experiment and mechanism","authors":"Long Ding, Hexi Zhao, Yafei Li, Yi-fan Wang, Hongming Long","doi":"10.1515/ijcre-2024-0081","DOIUrl":"https://doi.org/10.1515/ijcre-2024-0081","url":null,"abstract":"\u0000 The challenges posed by volatile organic compound (VOC) emissions in iron ore sintering flue gas are significant. La-based perovskite catalysts offer a promising solution for efficiently degrading VOCs. In this study, a series of LaBO3 (B = Cu, Fe, Cr, Mn, Co) perovskite catalysts were synthesized using the sol-gel method. The influence of various B-site elements on the catalyst’s structure and surface chemical properties was thoroughly examined. Simulations were conducted to assess the VOC reduction capabilities of these catalysts under conditions mimicking sintering flue gas composition. It was found that the crystallite size of the perovskite catalyst decreases as the ionic radius of the B-site elements increases, while the specific surface area, total pore volume, and average pore size increase correspondingly. Notably, LaCoO3 and LaMnO3 demonstrated exceptional activity, attributed primarily to their elevated surface oxygen concentration and oxygen migration capability, positioning them as highly promising materials for further development. Furthermore, a proposed mechanism elucidates the La-based perovskite catalytic reduction of toluene, wherein lattice oxygen and adsorbed oxygen undergo mutual conversion during the oxidation process. This mechanism aligns with the L-H and M-v-K models, providing a comprehensive understanding of the catalytic process.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"19 8","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141266707","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}
Pooja P. Sanap, Amit M. Katariya, Yogesh S. Mahajan
In this work, production of ethyl acetate (EtAc) using Fischer esterification between acetic acid (AcOH) and ethyl alcohol (EtOH) is presented. Batch kinetics was developed with EtOH as the limiting reactant to avoid the problems associated with unreacted ethanol in the final product. Regression was performed to estimate the parameters of the Langmuir Hinshelwood type kinetic equation. Reaction mass obtained during kinetics was subjected to separation and purification. Molecular sieves (MS) were used to remove water. Distillation (simple and extractive distillation – with entrainer, dimethyl sulfoxide, DMSO) was used to obtain almost pure AcOH, EtOH, EtAc and DMSO. Future work in reactive separation environment is indicated. Use of EtOH as the limiting reactant, use of MS for water removal and complete separation sequence are important features of this work.
{"title":"Ethyl acetate production by Fischer esterification: use of excess of acetic acid and complete separation sequence","authors":"Pooja P. Sanap, Amit M. Katariya, Yogesh S. Mahajan","doi":"10.1515/ijcre-2024-0019","DOIUrl":"https://doi.org/10.1515/ijcre-2024-0019","url":null,"abstract":"\u0000 In this work, production of ethyl acetate (EtAc) using Fischer esterification between acetic acid (AcOH) and ethyl alcohol (EtOH) is presented. Batch kinetics was developed with EtOH as the limiting reactant to avoid the problems associated with unreacted ethanol in the final product. Regression was performed to estimate the parameters of the Langmuir Hinshelwood type kinetic equation. Reaction mass obtained during kinetics was subjected to separation and purification. Molecular sieves (MS) were used to remove water. Distillation (simple and extractive distillation – with entrainer, dimethyl sulfoxide, DMSO) was used to obtain almost pure AcOH, EtOH, EtAc and DMSO. Future work in reactive separation environment is indicated. Use of EtOH as the limiting reactant, use of MS for water removal and complete separation sequence are important features of this work.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"51 5","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141098240","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}
Ailin Deng, Qiqi Ma, Yunxiang Hu, Xin Zhang, S. Yang, Nianhua Song, Wuji Sun, Xuejun Liu, Jianbing Ji
Tributyl aconitate is a new type of alternative plasticizer to phthalates. Amberlyst-15 was used to catalyze the esterification of aconitic acid and n-butanol for the preparation of tributyl aconitate in a cyclic fixed-bed reactor. The influence of the reaction conditions on the conversion was investigated. The results showed that the conversion of aconitic acid increased significantly with the rise of temperature and catalyst loading. The reaction conditions were optimized as: temperature: 115 °C; initial mass ratio of AA and n-butanol: 1:4; catalyst loading: 25 %; reaction absolute pressure: 85 kPa; volume flow rate: 30 mL min−1. Thermodynamics and kinetics of the reaction was studied. The non-ideality of the reaction system was rectified using the UNIFAC group contribution method. The kinetic process was simulated using the pseudo-homogeneous (PH) model, Eley-Rideal (E-R) model, and Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. The results revealed that the E-R model exhibited superior suitability in simulating the kinetic process.
丙酮酸三丁酯是邻苯二甲酸酯的一种新型替代增塑剂。在循环固定床反应器中，使用 Amberlyst-15 催化了乌头酸和正丁醇的酯化反应，以制备丙酸三丁酯。研究了反应条件对转化率的影响。结果表明，随着温度和催化剂装填量的增加，乌头酸的转化率显著提高。反应条件优化为：温度温度：115 °C；AA 和正丁醇的初始质量比：1:4；催化剂装填量：25 %；反应绝对压力：85 °C：25 %；反应绝对压力：85 kPa；体积流量：30 mL min-1：30 mL min-1。对反应的热力学和动力学进行了研究。使用 UNIFAC 组贡献法纠正了反应体系的非理想性。使用伪均质（PH）模型、Eley-Rideal（E-R）模型和 Langmuir-Hinshelwood-Hougen-Watson （LHHW）模型模拟了动力学过程。结果表明，E-R 模型在模拟动力学过程中表现出更优越的适用性。
{"title":"Thermodynamic and kinetic study on the catalysis of tributyl aconitate by Amberlyst-15 in a cyclic fixed-bed reactor","authors":"Ailin Deng, Qiqi Ma, Yunxiang Hu, Xin Zhang, S. Yang, Nianhua Song, Wuji Sun, Xuejun Liu, Jianbing Ji","doi":"10.1515/ijcre-2023-0222","DOIUrl":"https://doi.org/10.1515/ijcre-2023-0222","url":null,"abstract":"\u0000 Tributyl aconitate is a new type of alternative plasticizer to phthalates. Amberlyst-15 was used to catalyze the esterification of aconitic acid and n-butanol for the preparation of tributyl aconitate in a cyclic fixed-bed reactor. The influence of the reaction conditions on the conversion was investigated. The results showed that the conversion of aconitic acid increased significantly with the rise of temperature and catalyst loading. The reaction conditions were optimized as: temperature: 115 °C; initial mass ratio of AA and n-butanol: 1:4; catalyst loading: 25 %; reaction absolute pressure: 85 kPa; volume flow rate: 30 mL min−1. Thermodynamics and kinetics of the reaction was studied. The non-ideality of the reaction system was rectified using the UNIFAC group contribution method. The kinetic process was simulated using the pseudo-homogeneous (PH) model, Eley-Rideal (E-R) model, and Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. The results revealed that the E-R model exhibited superior suitability in simulating the kinetic process.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"46 5","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141098352","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}
Water Gas shift reaction (WGS) kinetics are prominent in reactions involving hydrocarbons. Often the rate expressions developed for WGS have narrow application for wider experimental conditions. On the other hand, DFT based microkinetic models developed for WGS can predict the experimental trend, however, developing rate expressions for the same can be difficult owing to the validity of different approximations and assumptions. In this context, R dot approach has been used in this study to develop rate expressions for WGS over Pt, Rh. Using this approach, the rate determining steps of the mechanisms proposed, validation with experimental data and most abundant reaction intermediate (MARI) analysis was carried out. Based on the interpreted results it has been seen that the R dot approach was able to predict the experimental trend to good degree of accuracy in line with the predictions of quasi steady state (QSS) approach.
{"title":"R dot approach for kinetic modelling of WGS over noble metals","authors":"Ravikiran Mandapaka","doi":"10.1515/ijcre-2023-0231","DOIUrl":"https://doi.org/10.1515/ijcre-2023-0231","url":null,"abstract":"\u0000 Water Gas shift reaction (WGS) kinetics are prominent in reactions involving hydrocarbons. Often the rate expressions developed for WGS have narrow application for wider experimental conditions. On the other hand, DFT based microkinetic models developed for WGS can predict the experimental trend, however, developing rate expressions for the same can be difficult owing to the validity of different approximations and assumptions. In this context, R dot approach has been used in this study to develop rate expressions for WGS over Pt, Rh. Using this approach, the rate determining steps of the mechanisms proposed, validation with experimental data and most abundant reaction intermediate (MARI) analysis was carried out. Based on the interpreted results it has been seen that the R dot approach was able to predict the experimental trend to good degree of accuracy in line with the predictions of quasi steady state (QSS) approach.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"9 4","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141098667","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}
Rahmad Syah, A. Bateni, Kamran Valizadeh, M. Elveny, Mehdi Shaeban Jahanian, D. Ramdan, A. Davarpanah
{"title":"Retraction of: Computational fluid dynamic simulations to improve heat transfer in shell tube heat exchangers","authors":"Rahmad Syah, A. Bateni, Kamran Valizadeh, M. Elveny, Mehdi Shaeban Jahanian, D. Ramdan, A. Davarpanah","doi":"10.1515/ijcre-2024-2001","DOIUrl":"https://doi.org/10.1515/ijcre-2024-2001","url":null,"abstract":"","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"64 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141101935","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}
M. Akram, Abhyuday Mallick, Debasish Sarkar, Sampa Chakrabarti
A laboratory scale continuous flow stirred tank reactor (CFSTR) has been developed for ultrasound-assisted Fenton degradation of Rhodamine B dye in simulated wastewater and its performances have been studied in the present work. The sono-reactor was made of glass, 6 cm in diameter and 17.5 cm in height; fitted with a cooling water jacket. The volume was about 0.4 L and the flow rate of dye solution was 20 mL min−1. Ultrasound was provided with a 120 W probe-type sonicator. The hydrodynamic characteristics were studied by RTD studies and CFD analysis in COMSOL Multiphysics software. The CFD analysis showed the reactor to be behaving like a CSTR with bypassing leading to a short residence time. The optimum treatment conditions in this reactor for degrading Rhodamine B solution were determined using Response Surface Methodology. A model equation correlating the decolorization percentage with the initial dye concentration, H2O2 and Fe2+ dosage (Fenton’s reagent) was developed which can predict the decolorization with a high degree of accuracy. Under optimum conditions, the percent decolorization was 55 and the corresponding COD removal was 15 %. A continuous sono-Fenton reactor, if scaled up properly, can be useful for degradation of dark coloured refractory organics in wastewater where photo-Fenton reaction is ineffective.
本研究开发了一种实验室规模的连续流动搅拌槽反应器（CFSTR），用于超声辅助芬顿降解模拟废水中的罗丹明 B 染料，并对其性能进行了研究。超声反应器由玻璃制成，直径 6 厘米，高 17.5 厘米，配有冷却水套。容积约为 0.4 升，染料溶液的流速为 20 毫升/分钟。超声波由 120 W 探头型超声器提供。通过热电阻研究和 COMSOL Multiphysics 软件中的 CFD 分析研究了流体动力学特性。CFD 分析表明，反应器的行为类似于 CSTR，旁路导致停留时间较短。采用响应面方法确定了该反应器中降解罗丹明 B 溶液的最佳处理条件。建立了一个脱色百分比与初始染料浓度、H2O2 和 Fe2+ 用量（芬顿试剂）相关的模型方程，该方程可以高度准确地预测脱色情况。在最佳条件下，脱色率为 55%，相应的 COD 去除率为 15%。连续式声波芬顿反应器如果规模适当，可用于降解废水中光-芬顿反应无效的深色难降解有机物。
{"title":"Design, characterization and performance evaluation of a laboratory-scale continuous reactor for sono-Fenton treatment of simulated wastewater","authors":"M. Akram, Abhyuday Mallick, Debasish Sarkar, Sampa Chakrabarti","doi":"10.1515/ijcre-2023-0238","DOIUrl":"https://doi.org/10.1515/ijcre-2023-0238","url":null,"abstract":"\u0000 A laboratory scale continuous flow stirred tank reactor (CFSTR) has been developed for ultrasound-assisted Fenton degradation of Rhodamine B dye in simulated wastewater and its performances have been studied in the present work. The sono-reactor was made of glass, 6 cm in diameter and 17.5 cm in height; fitted with a cooling water jacket. The volume was about 0.4 L and the flow rate of dye solution was 20 mL min−1. Ultrasound was provided with a 120 W probe-type sonicator. The hydrodynamic characteristics were studied by RTD studies and CFD analysis in COMSOL Multiphysics software. The CFD analysis showed the reactor to be behaving like a CSTR with bypassing leading to a short residence time. The optimum treatment conditions in this reactor for degrading Rhodamine B solution were determined using Response Surface Methodology. A model equation correlating the decolorization percentage with the initial dye concentration, H2O2 and Fe2+ dosage (Fenton’s reagent) was developed which can predict the decolorization with a high degree of accuracy. Under optimum conditions, the percent decolorization was 55 and the corresponding COD removal was 15 %. A continuous sono-Fenton reactor, if scaled up properly, can be useful for degradation of dark coloured refractory organics in wastewater where photo-Fenton reaction is ineffective.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"43 10","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141102100","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}
E. J. Sandoval-Herazo, Israel Rodríguez-Torres, G. Espinosa-Reyes, M. Lizardi-Jiménez
The superficial gas velocity (Ug) values of 1.0, 1.5 and 2.0 cm s−1 showed a diesel consumption of 59.70, 58.20 and 65.20 %, respectively. The productivity of the airlift bioreactors (ALBs) was 0.030, 0.026 and 0.034 g L−1 d−1, respectively. During 10 days of operation, the emulsification index (E 24 %) values for Ug 1.0, 2.0 and 2.0 cm s−1 were 15.79, 15.07 and 12.85 %, respectively. Likewise, an increase in the degradation and suspended solids was observed when increasing the Ug from 1.0 to 2.0 cm s−1 of the ALBs, whereas a decrease in emulsification index E 24 % was observed for an Ug of 2.0 cm s−1. According to the results, the Ug of 2.0 cm s−1 was the most effective for increasing the degradation of diesel and growth of the consortium among the Ug evaluated. Furthermore, the reduction of E 24 % in this Ug suggests that the consortium uses a mixed form of hydrocarbon consumption, both by direct contact and in emulsified form.
表层气体速度（Ug）值为 1.0、1.5 和 2.0 厘米/秒-1 时，柴油消耗量分别为 59.70%、58.20%和 65.20%。气提生物反应器（ALB）的生产率分别为 0.030、0.026 和 0.034 g L-1 d-1。在 10 天的运行期间，Ug 1.0、2.0 和 2.0 cm s-1 的乳化指数（E 24 %）值分别为 15.79、15.07 和 12.85 %。同样，当 ALB 的 Ug 值从 1.0 cm s-1 增加到 2.0 cm s-1 时，降解率和悬浮固体增加，而当 Ug 值为 2.0 cm s-1 时，乳化指数 E 24 % 下降。结果表明，在所评估的 Ug 值中，2.0 cm s-1 的 Ug 值对提高柴油降解和菌群生长最有效。此外，在该 Ug 下 E 值减少了 24%，这表明菌群采用混合形式消耗碳氢化合物，既有直接接触形式，也有乳化形式。
{"title":"Airlift bioreactors for bioremediation of water contaminated with hydrocarbons in agricultural regions","authors":"E. J. Sandoval-Herazo, Israel Rodríguez-Torres, G. Espinosa-Reyes, M. Lizardi-Jiménez","doi":"10.1515/ijcre-2024-0009","DOIUrl":"https://doi.org/10.1515/ijcre-2024-0009","url":null,"abstract":"\u0000 The superficial gas velocity (Ug) values of 1.0, 1.5 and 2.0 cm s−1 showed a diesel consumption of 59.70, 58.20 and 65.20 %, respectively. The productivity of the airlift bioreactors (ALBs) was 0.030, 0.026 and 0.034 g L−1 d−1, respectively. During 10 days of operation, the emulsification index (E\u0000 24 %) values for Ug 1.0, 2.0 and 2.0 cm s−1 were 15.79, 15.07 and 12.85 %, respectively. Likewise, an increase in the degradation and suspended solids was observed when increasing the Ug from 1.0 to 2.0 cm s−1 of the ALBs, whereas a decrease in emulsification index E\u0000 24 % was observed for an Ug of 2.0 cm s−1. According to the results, the Ug of 2.0 cm s−1 was the most effective for increasing the degradation of diesel and growth of the consortium among the Ug evaluated. Furthermore, the reduction of E\u0000 24 % in this Ug suggests that the consortium uses a mixed form of hydrocarbon consumption, both by direct contact and in emulsified form.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"125 10","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141115454","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}
In response to the observed phenomenon of poor fluid mixing within the reactor, this study proposes a novel mixing method to enhance fluid mixing efficiency. In this study, numerical simulation and purification tests were carried out for the purification of zinc sulfate solution. Numerical simulations were conducted to compare the effects of variable-speed stirring and uniform-speed stirring on mixing efficiency, considering both momentum transfer process and mass transfer process. The purification test further demonstrated a significant improvement in the reaction rate under variable-speed stirring, as evidenced by the analysis of purification efficiency and microscopic morphology. It was elaborated that the enhancement mechanism of variable-speed stirring involved disrupting the periodic order structure in the tank, leading to the generation of a multi-scale vortex that increased stirring kinetic energy to form a shear force. This force contributed to reducing the velocity slip between the impurity ions and zinc particles, consequently decreasing reaction time and enhancing purification rate. The results indicated that sinusoidal stirring yielded the most effective mixing. When implemented in practical production settings, it enhanced dimensionless mixing efficiency by 24.83 % compared to the homogeneous stirring system. Additionally, it reduced reaction time by 15.47 % and decreased mixing energy per unit volume by 32.38 %, while simultaneously lowering energy consumption by 24.77 %.
{"title":"Mechanism analysis and mixing characterization of variable-speed mechanical mixing enhancement","authors":"Yuchen Lin, Shibo Wang, Hua Wang, Jianxin Xu, Q. Xiao","doi":"10.1515/ijcre-2023-0239","DOIUrl":"https://doi.org/10.1515/ijcre-2023-0239","url":null,"abstract":"\u0000 In response to the observed phenomenon of poor fluid mixing within the reactor, this study proposes a novel mixing method to enhance fluid mixing efficiency. In this study, numerical simulation and purification tests were carried out for the purification of zinc sulfate solution. Numerical simulations were conducted to compare the effects of variable-speed stirring and uniform-speed stirring on mixing efficiency, considering both momentum transfer process and mass transfer process. The purification test further demonstrated a significant improvement in the reaction rate under variable-speed stirring, as evidenced by the analysis of purification efficiency and microscopic morphology. It was elaborated that the enhancement mechanism of variable-speed stirring involved disrupting the periodic order structure in the tank, leading to the generation of a multi-scale vortex that increased stirring kinetic energy to form a shear force. This force contributed to reducing the velocity slip between the impurity ions and zinc particles, consequently decreasing reaction time and enhancing purification rate. The results indicated that sinusoidal stirring yielded the most effective mixing. When implemented in practical production settings, it enhanced dimensionless mixing efficiency by 24.83 % compared to the homogeneous stirring system. Additionally, it reduced reaction time by 15.47 % and decreased mixing energy per unit volume by 32.38 %, while simultaneously lowering energy consumption by 24.77 %.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":" 365","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140682453","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}
Suha Abad, Ruqaiya Aziz, Mohd. Junaid Khalil, Muhammad Muhitur Rahman, Mohammad M. Hossain
This study is focused on elucidating the potential effectiveness of degradation as a method to eliminate dyes from aqueous systems. Specifically, it delves into the influence of ultrasound energy on the degradation kinetics of a dye. The research findings underscore the notable impact of ultrasound energy in accelerating the reaction rate constant (k p), with the degradation kinetics exhibiting a conformity to first-order kinetics. An integral aspect of the study involves the establishment of a robust relationship between time and concentration by integrating the equation governing the degradation of the dye. Additionally, the determination of the rate constant, derived from the gradients of the graphs, attests to the model’s fitting accuracy. Intriguingly, the outcomes of this analysis reveal no discernible structural changes in the dye. The accuracy of the model is further underscored by the establishment of linear relations derived from experimental data. Summarily, this kinetic study provides invaluable insights into the multifaceted impact of ultrasound energy and the Fe2O3 catalytic influence on both the degradation kinetics of the dye. The comprehensive nature of the investigation enhances our understanding of the intricate processes involved, contributing significantly to the broader field of water treatment and dye removal from aqueous environments.
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The hydrodynamics of a conical spouted bed was simulated utilizing the Eulerian–Eulerian Two-Fluid Model (TFM) incorporating a kinetic theory of granular flows. The simulations were confirmed with experimental data. To accurately examine the pyrolysis process, the hydrodynamics of the solid bed as well as the heat transfer inside it were analysed separately by considering a precise synthetic model. The effects of gas velocity, particle size, bed length, and temperature were thoroughly investigated. The results indicated that the amount of relative standard deviation increases with an increase in the inlet velocity into the bed. This amount of deviation at the inlet velocity (0.6 m/s for tar and gas flow to its maximum value of 9.1 and 9.4) is not desirable in product production and should be modified so that the amount of gas flow increases and the tar produced reaches the minimum possible amount. Also, the graphs of the relative standard deviation in terms of temperature indicate that the increase in temperature from 730 to 950 K is associated with a relatively smaller fluctuation of the relative standard deviation so that at the temperature of 730 K, it is 7.2 % for tar and 6.4 % for gas flow, while at temperature of 950 K, it is 6.5 % for wire and 6.8 % for gas flow. Finally, the results determined that small-diameter particles have a more significant fountain height and also higher velocity in the spout section.
利用包含颗粒流动动力学理论的欧拉-欧拉双流体模型（TFM）模拟了锥形喷流床的流体力学。模拟结果得到了实验数据的证实。为了准确检验热解过程，通过考虑一个精确的合成模型，分别分析了固体床的流体力学及其内部的热传导。对气体速度、颗粒大小、床层长度和温度的影响进行了深入研究。结果表明，相对标准偏差量随着床层入口速度的增加而增加。这种入口速度下的偏差量（焦油和气体流量为 0.6 m/s，最大值分别为 9.1 和 9.4）在产品生产中是不可取的，应加以修改，使气体流量增加，焦油产量达到最小值。此外，与温度有关的相对标准偏差图显示，温度从 730 K 升至 950 K 时，相对标准偏差的波动相对较小，因此在温度为 730 K 时，焦油的相对标准偏差为 7.2%，气体流量的相对标准偏差为 6.4%；而在温度为 950 K 时，金属丝的相对标准偏差为 6.5%，气体流量的相对标准偏差为 6.8%。最后，研究结果表明，小直径颗粒的喷泉高度更大，在喷口部分的速度也更高。
{"title":"Investigation of polymers pyrolysis in a solid-gas conical spouted bed: CFD simulation","authors":"Sobhan Jafari, Hadi Soltani, M. Gholizadeh","doi":"10.1515/ijcre-2023-0209","DOIUrl":"https://doi.org/10.1515/ijcre-2023-0209","url":null,"abstract":"\u0000 The hydrodynamics of a conical spouted bed was simulated utilizing the Eulerian–Eulerian Two-Fluid Model (TFM) incorporating a kinetic theory of granular flows. The simulations were confirmed with experimental data. To accurately examine the pyrolysis process, the hydrodynamics of the solid bed as well as the heat transfer inside it were analysed separately by considering a precise synthetic model. The effects of gas velocity, particle size, bed length, and temperature were thoroughly investigated. The results indicated that the amount of relative standard deviation increases with an increase in the inlet velocity into the bed. This amount of deviation at the inlet velocity (0.6 m/s for tar and gas flow to its maximum value of 9.1 and 9.4) is not desirable in product production and should be modified so that the amount of gas flow increases and the tar produced reaches the minimum possible amount. Also, the graphs of the relative standard deviation in terms of temperature indicate that the increase in temperature from 730 to 950 K is associated with a relatively smaller fluctuation of the relative standard deviation so that at the temperature of 730 K, it is 7.2 % for tar and 6.4 % for gas flow, while at temperature of 950 K, it is 6.5 % for wire and 6.8 % for gas flow. Finally, the results determined that small-diameter particles have a more significant fountain height and also higher velocity in the spout section.","PeriodicalId":51069,"journal":{"name":"International Journal of Chemical Reactor Engineering","volume":"58 7","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140748539","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}
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