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.

CFD-based compartmental modeling of single phase stirred-tank reactors

AIChE Journal ◽  
2006 ◽  
Vol 52 (5) ◽  
pp. 1836-1846 ◽  
Author(s):  
Debangshu Guha ◽  
M. P. Dudukovic ◽  
P. A. Ramachandran ◽  
S. Mehta ◽  
J. Alvare
Keyword(s):  
Single Phase ◽  
Stirred Tank ◽  
Compartmental Modeling ◽  
Stirred Tank Reactors

scholarly journals Biomagnetic Monitoring vs. CFD Modeling: A Real Case Study of Near-Source Depositions of Traffic-Related Particulate Matter along a Motorway

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1285
Author(s):  
Sarah Letaïef ◽  
Pierre Camps ◽  
Thierry Poidras ◽  
Patrick Nicol ◽  
Delphine Bosch ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particulate Matter ◽  
Cfd Simulation ◽  
Low Cost ◽  
Precast Concrete ◽  
Cfd Modeling ◽  
Concrete Wall ◽  
Fluorescence Measurements ◽  
Computational Fluid Dynamics Cfd

A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on the site with three vegetated flat-top earth berms of a basic design, and a fourth one was located windward to the traffic roofed with a 4-m-high precast concrete wall. As a first step, PM deposition simultaneously on plant leaves, on low-cost passive artificial filters, and on soils was estimated from proxies supplied by magnetic and X-ray fluorescence measurements on both sides of the motorway. These latter revealed that traffic-related pollutants are present on soils samples highlighted with a clear fingerprint of combustion residues, and wears of breaks, vehicles, and highway equipment. Maximum PM accumulations were detected in the lee of the berm–wall combination, while no significant deposition was observed on both sides of the flat-top earth berms. These results are in line with measurements from PM µ-sensors operated by the regional state-approved air quality agency. Finally, we compared the experimental measurements with the outcomes of a computational fluid dynamics (CFD) modeling based on the Reynolds-Averaged Navier–Stokes (RANS) equations that consider the traffic-induced momentum and turbulence. The CFD modeling matches the experimental results by predicting a recirculated flow in the near wake of the berm–wall combination that enhances the PM concentration, whereas the flat-top berm geometry does not alter the pollutants’ transport and indeed contributes to their atmospheric dispersion.

Turbulent Flow in a Stirred Tank With Permeable Impeller Blades

2002 ◽  
Author(s):  
H. P. Kritzinger ◽  
B. C. Deelder ◽  
C. R. Kleijn ◽  
J. J. Derksen ◽  
H. E. A. Van den Akker
Keyword(s):  
Single Phase ◽  
Stirred Tank ◽  
Impeller Speed ◽  
Catalyst Supports ◽  
Velocity Data ◽  
Single Phase Flow ◽  
Stirred Tank Reactors ◽  
Type Flow ◽  
Monolith Catalyst ◽  
Tip Velocity

This paper presents results from the experimental investigation of single-phase flow in a prototype stirred tank reactor, which uses monolith catalyst blocks as impeller. These monolith catalyst supports have been used for a dual role: (i) as stirrer blades for agitation and (ii) to bring reactants in contact with the catalyst in a way that eliminates the need for product filtration. The reactors are under investigation as replacement for the standard slurry stirred tank reactors used in the catalytic processes in chemical industry. The flow field in the reactor with this novel impeller, was determined using LDA. Mean and fluctuating velocity data were measured for different monolith blocks and impeller speeds. Results show the normalized flow in the bulk of the tank to be independent of impeller speed and monolith type. Flow velocities through the monolith channels, which are crucial to bring the reactants in contact with the catalyst impregnated in the monolith walls, were measured with LDA. These velocities were found to be of the order of 30–70% of the impeller tip velocity, dependent on the impeller speed and monolith type.

Experimental and theoretical analyses of two-dimensional flows upstream of broad-crested weirs

2008 ◽  
Vol 35 (9) ◽  
pp. 975-986 ◽  
Author(s):  
M. Salih Kirkgoz ◽  
M. Sami Akoz ◽  
A. Alper Oner
Keyword(s):  
Cfd Simulation ◽  
Turbulence Models ◽  
Free Surface Flows ◽  
Velocity Fields ◽  
Numerical Results ◽  
Cfd Modeling ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Using the particle image velocimetry (PIV) technique, the laboratory experiments are conducted to measure the velocity fields of two-dimensional turbulent free surface flows upstream of rectangular and triangular broad-crested weirs. The experimental flow cases are analyzed theoretically by a computational fluid dynamics (CFD) modeling in which the finite element method is used to solve the governing equations. In the CFD simulation, the volume of fluid (VOF) method is used to compute the free surfaces of the flows. Using the standard k–ε and standard k–ω turbulence models, the numerical results for the velocity fields and flow profiles are compared with the experimental results for validation purposes. The computed results using k–ω turbulence model on compressed mesh systems are found in good agreement with measured data. The flow cases are also analyzed theoretically using the potential flow (PF) approach, and the numerical results for the velocity fields are compared with measurements.

CFD Simulation of Solid Suspension in a Stirred Reactor Driven by a Dual Punched Rigid-Flexible Impeller

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Deyin Gu ◽  
Zuohua Liu ◽  
Facheng Qiu ◽  
Jun Li ◽  
Changyuan Tao ◽  
...  
Keyword(s):  
Reference Frames ◽  
Cfd Simulation ◽  
Energy Dissipation Rate ◽  
Solid Particles ◽  
Stirred Tank ◽  
Two Phase ◽  
Stirred Reactor ◽  
Solid Suspension ◽  
Computational Fluid Dynamics Cfd ◽  
Solid Liquid

Abstract Solid suspension characteristics were predicted by computational fluid dynamics (CFD) simulation in a stirred tank driven by a dual rigid-flexible impeller and a dual punched rigid-flexible impeller. An Eulerian-Eulerian approach, standard k-ε turbulence model, and multiple reference frames (MRF) technique were employed to simulate the solid-liquid two-phase flow, turbulent flow, and impeller rotation in the stirred tank, respectively. The CFD results showed that dual punched rigid-flexible impeller could increase the axial velocity and turbulent kinetic energy dissipation rate, and decrease the quantity of sediment solid particles compared with dual rigid-flexible impeller. Less impeller power was consumed by dual punched rigid-flexible impeller compared with dual rigid-flexible impeller at the same impeller speed. It was found that punched rigid-flexible impeller was more efficient in terms of solid suspension quality than dual rigid-flexible impeller at the same Pw. The simulated results for the axial solid concentration were in good agreement with the experimental data.

scholarly journals Performance Investigation of The Bed Adsorption of An Adsorption Desalination Using CFD Simulation

2021 ◽  
Author(s):  
Mohamad Hossein Bakhshandeh ◽  
Taleb Zarei ◽  
Jamshid Khorshidi
Keyword(s):  
Silica Gel ◽  
Water Uptake ◽  
Cfd Simulation ◽  
Finned Tube ◽  
Copper Plate ◽  
Cfd Modeling ◽  
Desorption Process ◽  
Critical Elements ◽  
Computational Fluid Dynamics Cfd ◽  
Fin Thickness

Abstract One of the critical elements of an adsorption desalination system is the adsorption bed. System dynamics of a 2-bed single-stage silica gel plus water-based AD system was analyzed. A great pattern is expanded using energy conservation and mass connected with the kinetics of the ad- sorption/desorption process. Computational fluid dynamics (CFD) modeling was handled for simulation of the adsorption process for a rectangular finned tube-based adsorption bed featured with silica gel adsorbent substance. For the simulation, the adsorbents were considered as a solid volume with defined porosity based on Darcy equation. The adsorption and desorption mode of the adsorption bed was simulated. The CFD techniques were then applied to study fin thickness and fin height. The results showed that decreasing the fin thickness increased the water uptake by up to 8% and decreased the fin height from 30mm to 20mm, which resulted in an increase of the water uptake up to 17%. The CFD technique was also used to investigate the effect of plate type on the adsorption bed performance. The results showed that the copper plate improved the water uptake up to 9%. The copper plate decreased the temperature of the adsorption bed up to 11% more than the aluminum plate.

Characterization of Single-Phase Flow Hydrodynamics in Berty Reactor using Computational Fluid Dynamics (CFD)

2021 ◽  
Author(s):  
Khunnawat Ountaksinkul ◽  
Sirada Sripinun ◽  
Panut Bumphenkiattikul ◽  
Surapon Bubphacharoen ◽  
Arthit Vongachariya ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Single Phase ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Kinetic Studies ◽  
Stirred Tank Reactors ◽  
Computational Fluid Dynamics Cfd ◽  
Continuous Stirred Tank

This work studies the flow characteristics in the Berty reactor, a gradientless reactor for kinetic studies, using three-dimensional (3D) computational fluid dynamics (CFD), and the non-ideal continuous stirred tank reactors...

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