scholarly journals CFD Simulation of Flows in Stirred Tank Reactors Through Prediction of Momentum Source

10.5772/51754 ◽  
2013 ◽  
Author(s):  
Weidong Huang ◽  
Kun Li
Keyword(s):  
Cfd Simulation ◽  
Stirred Tank ◽  
Stirred Tank Reactors

CFD Simulation of Average and Local Gas–Liquid Flow Properties in Stirred Tank Reactors with Multiple Rushton Impellers

2017 ◽  
Vol 50 (12) ◽  
pp. 878-891 ◽  
Author(s):  
Ao Pan ◽  
Minghui Xie ◽  
Chao Li ◽  
Jianye Xia ◽  
Ju Chu ◽  
...  
Keyword(s):  
Liquid Flow ◽  
Cfd Simulation ◽  
Stirred Tank ◽  
Flow Properties ◽  
Stirred Tank Reactors ◽  
Gas Liquid Flow

CFD simulation of accidents in industrial batch stirred tank reactors

2007 ◽  
Vol 62 (18-20) ◽  
pp. 4920-4925 ◽  
Author(s):  
A. Milewska ◽  
E.J. Molga
Keyword(s):  
Cfd Simulation ◽  
Stirred Tank ◽  
Stirred Tank Reactors ◽  
Industrial Batch

CFD Modeling and Simulation of Transesterification Reactions of Vegetable Oils with an Alcohol in Baffled Stirred Tank Reactors

2013 ◽  
Vol 390 ◽  
pp. 86-90 ◽  
Author(s):  
Isabela M. Poley ◽  
Leandro S. Oliveira
Keyword(s):  
Single Phase ◽  
Cfd Simulation ◽  
Reaction Rates ◽  
Stirred Tank ◽  
Cfd Modeling ◽  
Stirred Tanks ◽  
Stirred Tank Reactors ◽  
Surface Contact ◽  
Successful Design ◽  
Computational Fluid Dynamics Cfd

Alcohol and triglycerides do not form a single phase mixture and thus there is a poor surface contact between them causing transesterification to proceed relatively slow. Introduction of stirring improves the surface contact and consequently the reaction rates and biodiesel yields. Thus, in industrial processes, transesterification is usually carried out in stirred tank reactors. Investigating how this type of reactor works is necessary for successful design, operation and optimization. Experimental methods for investigating flow-fields and chemical reactions are expensive and time demanding and cannot meet this challenge accurately. An alternate way is to model and simulate stirred tanks by computational fluid dynamics (CFD). Thus, in this work, a CFD simulation of transesterification was performed, with reaction rates being evaluated by solving a set of differential equations describing the reaction kinetics. The concentrations profiles for the expected components were in accordance with the kinetic model, and the mass fraction patterns showed efficient mixture.

Removal of lead by sulfate-reducing bacteria in anaerobic continuous stirred tank reactors

2016 ◽  
Vol 14 (3) ◽  
pp. 557-561
Author(s):  
Nguyễn Thị Yên ◽  
Kiều Thị Quỳnh Hoa
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Stirred Tank ◽  
Synthetic Wastewater ◽  
Terminal Electron Acceptor ◽  
Stirred Tank Reactors ◽  
Sulfate Reducing ◽  
Sulfide Production ◽  
Continuous Stirred Tank ◽  
Continuous Stirred Tank Reactors ◽  
Reducing Bacteria

Lead contaminated wastewater negatively impacts to living organisms as well as humans. In recent years, a highly promising biological process using the anaerobic production of sulfide ions by sulfate-reducing bacteria has presented itself as an alternative option for the removal of lead. This process is based on microbial utilization of electron donors, such as organic compounds (carbon sources), and sulfate as the terminal electron acceptor for sulfide production. The biogenic hydrogen sulfide reacts with dissolved heavy metals to form insoluble metal sulfide precipitates Removal of lead by an enriched consortium of sulfate-reducing bacteria (DM10) was evaluated sulfate reduction, sulfide production and lead precipitation. Four parallel anaerobic continuous stirred tank reactors (CSTR, V = 2L) (referred as R1 - R4) were fed with synthetic wastewater containing Pb2+ in the concentrations of 0, 100, 150 and 200 mg L-1 of lead and operated with a hydraulic retention time of 5 days for 40 days. The loading rates of each metal in R1- R4 were 0, 20, 30 and 40 mg L-1 d-1, respectively. The results showed that there was no inhibition of SRB growth and that lead removal efficiencies of 99-100% for Pb2+ were achieved in R2 (100 mg L-1) and R3 (150 mg L-1) throughout the experiment. For the highest lead concentration of  200 mg L-1, a decrease in efficiency of removal (from 100 to 96%) was observed at the end of the experiment. The obtained result of this study might help for a better control operation and performance improvements of reactors.

scholarly journals Process Engineering of the Acetone-Ethanol-Butanol (ABE) Fermentation in a Linear and Feedback Loop Cascade of Continuous Stirred Tank Reactors: Experiments, Modeling and Optimization

Fuels ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 108-129
Author(s):  
Katja Karstens ◽  
Sergej Trippel ◽  
Peter Götz
Keyword(s):  
Feedback Loop ◽  
Early Stage ◽  
Formation Rate ◽  
Abe Fermentation ◽  
Operating Conditions ◽  
Stirred Tank ◽  
Second Phase ◽  
Stirred Tank Reactors ◽  
Continuous Stirred Tank ◽  
Continuous Stirred Tank Reactors

The production of butanol, acetone and ethanol by Clostridium acetobutylicum is a biphasic fermentation process. In the first phase the carbohydrate substrate is metabolized to acetic and butyric acid, in the following second phase the product spectrum is shifted towards the economically interesting solvents. Here we present a cascade of six continuous stirred tank reactors (CCSTR), which allows performing the time dependent metabolic phases of an acetone-butanol-ethanol (ABE) batch fermentation in a spatial domain. Experimental data of steady states under four operating conditions—with variations of the pH in the first bioreactor between 4.3 and 5.6 as well as the total dilution rate between 0.042 h−1 and 0.092 h−1—were used to optimize and validate a corresponding mathematical model. Beyond a residence time distribution representation and substrate, biomass and product kinetics this model also includes the differentiation of cells between the metabolic states. Model simulations predict a final product concentration of 8.2 g butanol L−1 and a productivity of 0.75 g butanol L−1 h−1 in the CCSTR operated at pHbr1 of 4.3 and D = 0.092 h−1, while 31% of the cells are differentiated to the solventogenic state. Aiming at an enrichment of solvent-producing cells, a feedback loop was introduced into the cascade, sending cells from a later state of the process (bioreactor 4) back to an early stage of the process (bioreactor 2). In agreement with the experimental observations, the model accurately predicted an increase in butanol formation rate in bioreactor stages 2 and 3, resulting in an overall butanol productivity of 0.76 g L−1 h−1 for the feedback loop cascade. The here presented CCSTR and the validated model will serve to investigate further ABE fermentation strategies for a controlled metabolic switch.

scholarly journals Novel Evaluation Method to Determine the Local Mixing Time Distribution in Stirred Tank Reactors

2021 ◽  
pp. 100098
Author(s):  
J. Fitschen ◽  
S. Hofmann ◽  
J. Wutz ◽  
A.v. Kameke ◽  
M. Hoffmann ◽  
...  
Keyword(s):  
Time Distribution ◽  
Evaluation Method ◽  
Mixing Time ◽  
Stirred Tank ◽  
Stirred Tank Reactors

CFD simulation of particle suspension in a stirred tank

Particuology ◽  
2013 ◽  
Vol 11 (3) ◽  
pp. 317-326 ◽  
Author(s):  
Nana Qi ◽  
Hu Zhang ◽  
Kai Zhang ◽  
Gang Xu ◽  
Yongping Yang
Keyword(s):  
Cfd Simulation ◽  
Stirred Tank ◽  
Particle Suspension
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