Rotor-stator Spinning Disc Research Articles

The Transportation of Maxwell Fluid in the Rotating and Stretching System: Rotor-Stator Spinning Disc Reactor Applications

We have developed a mathematical model and obtained a numerical solution for the motion of a non-Newtonian Maxwell fluid between two disks having rotation and stretching velocity with convective boundary constraints, porous medium and thermal radiation. The present Maxwell fluid flow model with specified boundary constraints is not discussed so far. The proposed model has a lot of applications in electrical power generation, nuclear energy plants, astrophysical flows, space vehicles, geothermal extractions, and spinning disc reactor. The Von Karman similarity approach is used for the solution and validation of the solution is also provided. The solution is obtained numerically with finite difference method (FDM) based ND-solve command in Mathematica software. The effects of magnetic field, porous medium, radiation parameter, Deborah number, Prandtl number, and Reynolds number on skin friction, heat transfer, flow and temperature fields are discussed in detail. Due to the significant void fraction in the medium, porosity parameter shows unique trend compared to other parameters for the radial velocity profile. It has tendency to enhance the radial velocity near both the disc but in the middle part of system, porosity parameter retards radial velocity significantly.

Demulsification of phosphoric acid/ tri-n‑butyl phosphate (W/O) emulsion by a novel rotor-stator spinning disc device

The demulsification process of phosphoric acid/tri-n‑butyl phosphate (W/O) emulsion is investigated by a novel rotor-stator spinning disc device (RSSDD). Emulsion properties varied with emulsification rotor speed and phase ratio, and operating parameters such as flow rate and disc speed have been studied for their effects on demulsification efficiency D, relative volume of separated oil phase λ, dispersed phase fraction of creamed emulsion ɸc and change in the average droplet size of emulsion Δdc. The results show that D is primarily due to emulsion stability. Low emulsification rotor speed and phase ratio reduce the emulsion stability, resulting in an increase in D. The shear and centrifugal forces from rotation and the residence time, influenced by operating parameters, play a major role in D and Δdc. Operating at higher disc speed and lower flow rate is not supposed. D decreases with increasing flow rate and decreasing disc speed, while Δdc behaves in the opposite way. λ disperses within 1.52%-2.94%, resulting in a linear relationship between D and ɸc. The optimal operating parameters are determined with D of 41.12% for one cycle in RSSDD. A model is proposed for the prediction of D and ɸc, showing an acceptable agreement with the experimental results.

Scale-Up of a Heterogeneous Photocatalytic Degradation Using a Photochemical Rotor-Stator Spinning Disk Reactor.

Many chemical reactions contain heterogeneous reagents, products, byproducts, or catalysts, making their transposition from batch to continuous-flow processing challenging. Herein, we report the use of a photochemical rotor–stator spinning disk reactor (pRS-SDR) that can handle and scale solid-containing photochemical reaction conditions in flow. Its ability to handle slurries was showcased for the TiO2-mediated aerobic photodegradation of aqueous methylene blue. The use of a fast rotating disk imposes high shear forces on the multiphase reaction mixture, ensuring its homogenization, increasing the mass transfer, and improving the irradiation profile of the reaction mixture. The pRS-SDR performance was also compared to other lab-scale reactors in terms of water treated per reactor volume and light power input.

Modeling of extraction chromium (III) using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl in rotor stator spinning disc reactor

To overcome the disadvantages of large mass transfer resistance, long processing time and high investment in the previous extraction equipments, rotor-stator spinning disc reactor (RSSDR) was developed. Because of complex hydrodynamics in the RSSDR, a theoretical model was then established to simulate the extraction performance of chromium (III) using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl as extraction agent. Some important hydrodynamics behaviors were included in the model, such as liquid film thickness, liquid holdup, liquid residence time, mass transfer rate of the surface of the aqueous phase to the organic phase and mass transfer rate of the interior of aqueous phase to the surface. After verified by the experimental results, the effects of rotational speed, liquid flow rate and rotor-stator distance on extraction efficiency were predicted by the model. And then, the contribution ratios of liquid film thickness, liquid holdup, liquid residence time and mass transfer rate on extraction efficiency were detailed analyzed. The extraction process in the RSSDR could be in-depth understanding by the model, and the process of industrialization and other harmful matter removal could be effective guided.

Esterification of free fatty acids in a rotor-stator spinning disc reactor

Esterification of free fatty acids in a rotor-stator spinning disc reactor

Droplet size and liquid-liquid mass transfer with reaction in a rotor-stator Spinning Disk Reactor

A liquid–liquid test reaction system involving mass transfer with competitive reactions was used to show the potential for Process Intensification of the rotor–stator Spinning Disk Reactor (rs-SDR) in comparison with batch operation in a Stirred Vessel (SV). Under the investigated conditions, the SV showed a dispersion of droplets of a Sauter diameter d32 between 120 and 75μm, while the rs-SDR achieved values between 35 and 2.5μm due to the high shear forces. In terms of selectivity towards the undesired product, XS, the SV showed a decrease from 0.35 to 0.24 by increasing agitation, while the rs-SDR achieved values from 0.13 to 0.09. By modeling the system, the corresponding values for overall volumetric mass transfer coefficient kLa were one order of magnitude higher in the rs-SDR and as high as 0.24s-1. However, such values are much lower than the expected from the small droplet size. Literature suggests that the system is mass transfer limited, due to the formation of a monolayer of undissociated molecules around the interface. A model of diffusion with reaction is used to further model such effect. The model predicts well the product distribution experimentally obtained in the SV, although underestimates the values from the rs-SDR.

The mixing sensitivity of toluene and ethylbenzene sulfonation using fuming sulfuric acid studied in a rotor-stator spinning disc reactor

The mixing sensitivity was studied for the sulfonation of two alkylbenzenes (ArH’s), toluene and ethylbenzene, by using a rotor-stator spinning disc reactor (SDR). Fuming sulfuric acid (FSA), containing 30 wt. % free sulfur trioxide, was used as a sulfonating agent, which resulted in a fast, exothermic, and viscous liquid-liquid reaction system. Experiments were conducted by varying the SDRs’ rotational speed between 50 and 9000 rpm. In addition, different molar flow ratios (ArH:FSA) were investigated, ranging from 0.8 to 3.2, while operating at a maximum residence time of 7.1 s. The selectivity towards mono-sulfonated products was found to increase significantly at a higher rotational speed. This was observed consistently for both alkylbenzenes and all molar flow ratios, confirming the mixing sensitivity of the two alkylbenzene sulfonation reactions. Furthermore, it was proposed that the mixing sensitivity arises from a competition that exists between the desired and highly reactive primary sulfonation and the much less reactive consecutive sulfonation step to disulfonic acids.

CFD simulation of liquid flow characteristics in a rotor-stator spinning disc reactor

In this work, the CFD approach is employed to analyse the liquid hydrodynamic behaviour in the rotor-stator spinning disc reactor (RSSDR). The effect of rotational speed (N) and volume flow rate (Q) on the liquid-liquid flow pattern and its transition are investigated. It is found that there are two typical flow pattern (film flow and filament flow) observed in the RSSDR. Increasing N and decreasing Q turn the film flow into the filament flow. The flow pattern criterion for transition of filament flow to film flow is also obtained. The simulation data show a good agreement with our previous published experimental results. In addition, the influence of N and Q on liquid holdup rate (ε) and liquid velocity distribution in the RSSDR are also studied. The results show that ε keeps stable and then decreases with the increase of N, increases and then keeps consistent with increasing Q. While the mean liquid velocity increases as increasing N, Q, and radial radius (r). The mean radial velocity increases with increasing N, Q, and decreasing r. This work leads a deep understanding of the liquid flow characteristics in the RSSDR and its optimization design and scaling up.

Additions to "Micromixing in a Rotor-Stator Spinning Disc Reactor".

ADVERTISEMENT RETURN TO ISSUEPREVCorrespondenceNEXTAdditions to “Micromixing in a Rotor-Stator Spinning Disc Reactor”Arturo N. Manzano MartínezArturo N. Manzano MartínezLaboratory of Chemical Reactor Engineering, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The NetherlandsMore by Arturo N. Manzano Martínezhttp://orcid.org/0000-0001-9608-1527, Kevin M. P. van EetenKevin M. P. van EetenLaboratory of Chemical Reactor Engineering, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The NetherlandsMore by Kevin M. P. van Eeten, Jaap C. SchoutenJaap C. SchoutenLaboratory of Chemical Reactor Engineering, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The NetherlandsMore by Jaap C. Schoutenhttp://orcid.org/0000-0001-5706-7087, and John van der Schaaf*John van der SchaafLaboratory of Chemical Reactor Engineering, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands*E-mail: [email protected]More by John van der Schaafhttp://orcid.org/0000-0002-2856-8592Cite this: Ind. Eng. Chem. Res. 2020, 59, 36, 16095–16097Publication Date (Web):August 27, 2020Publication History Published online27 August 2020Published inissue 9 September 2020https://doi.org/10.1021/acs.iecr.0c03157Copyright © 2020 American Chemical SocietyRIGHTS & PERMISSIONSACS AuthorChoicewith CC-BY-NC-NDlicenseArticle Views876Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (808 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Energy,Ionic strength,Kinetic modeling,Perchlorates,Sulfuric acid Get e-Alerts

Process intensification of a photochemical oxidation reaction using a Rotor-Stator Spinning Disk Reactor: A strategy for scale up

Photochemical transformations have witnessed a remarkable growth of attention in the past decade due to the popularity of photoredox catalysis and the technological progress in energy-efficient light sources. However, the scaling of these photon-induced processes remains a daunting challenge for chemists and engineers in the industry, often discouraging their implementation in the production of fine chemicals and pharmaceuticals. To address this key issue, we report herein the development of a conceptually new photochemical reactor, called photo Rotor-Stator Spinning Disk Reactor. The photocatalyzed gas–liquid oxidation of α-terpinene to the drug ascaridole with Rose Bengal as photocatalyst was achieved with throughputs of over 1 kg·day−1 (270 mmol·h−1) under visible light irradiation. The performance of the reactor is correlated to various process parameters such as rotation speed, liquid flowrate, and catalyst concentration, among others. The conversion and selectivity increase from 37% to 97% and 75% to 90% respectively with an increase of rotation speed from 100 to 2000 RPM. The reactor operates with negligible pressure drop and allows for facile fine-tuning of the mixing efficiency. In this paper, we have also compared the performance of this reactor to other reactors such as the batch, micro, thin-film, and the vortex reactor, among others, and have found the photo-Rotor-Stator Spinning Disk Reactor to have superior productivity as well as higher productivity per volume (2.8 mol ·s−1 ·m−3). The findings of this study can be used to study, design, optimize and scale photochemical processes using the rotor–stator spinning disk reactor.

Extraction of chromium (III) from aqueous waste solution in a novel rotor-stator spinning disc reactor

In this work, the removal of chromium (III) from aqueous waste solution by solvent extraction with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl (P507) as extractant is investigated in a novel rotor-stator spinning disc reactor. The effect of rotational speed, volumetric flow rate and rotor-stator distance on extraction efficiency and volumetric mass transfer coefficient are studied. Experimental results indicates that the maximum values of extraction efficiency and volumetric mass transfer coefficient are 97.2 % and 0.40 1/s, respectively. The mass transfer performance inside the rotor-stator spinning disc reactor exceeds that of conventional reactors. Moreover, it is found that the extraction efficiency increases with the increase of rotational speed but with the decrease of volumetric flow rate and rotor-stator distance. The Volumetric mass transfer coefficient increases as both the rotational speed and volumetric flow rate increase, but decreases with the increase of rotor-stator distance. Furthermore, an analysis on the relationships between volumetric mass transfer coefficient and various parameters is launched by the grey correlation method. The calculation result shows good coincidence with the experimental data.

Experimental investigation on the flow and flow-rotor heat transfer in a rotor-stator spinning disk reactor

In this article, an experimental study has been conducted to provide better understanding of the flow and heat transfer characteristics in the front chamber of a rotor-stator spinning disk reactor. According to the measurements with a one-dimensional hot-wire anemometer probe, the effects of the axial gap width and the temperature on the core swirl ratio are investigated, which are ignored for the past decades. The values of the core swirl ratio are found to decrease by up to 12.2% when G increases from 0.0125 to 0.05 and reduce by up to 6% when the temperature rises from 300 K to 350 K. The measured moment coefficient, which primarily decides the energy dissipation rate, is analyzed according to the flow patterns for the first time. The transient thermochromic liquid crystal technique is used to estimate the heat transfer characteristic. The variations of the moment coefficient, the local Nusselt number and the average Nusselt number appear to be largely determined by the flow patterns. An empirical correlation of the average Nusselt number in the viscous section is determined for the first time, which is aimed to provide better predictions on the average heat transfer capacity. The interaction of the average Nusselt number with the moment coefficient is also introduced. It is speculated that the flow patterns in the chamber plays an important role in the energy dissipation and the heat transfer performance.

Epoxidation of methyl oleate in a rotor-stator spinning disc reactor

The intensification of the epoxidation of methyl oleate with hydrogen peroxide and formic acid in a rotor-stator spinning disc reactor (RSSDR) was studied in dependence of temperature, rotational disc speed and reactor throughput. The application of TiO2 as heterogeneous catalyst immobilized with Nafion® as adhesive on the rotor disc was also examined. Optimum values for the regarded parameters with respect to conversion and yield were 80 °C, 1000 min−1 and 50 mL min−1. The use of TiO2 as catalyst yielded no beneficial results as opposed to a plain steel rotor. A significant increase in yield and conversion were achieved with the RSSDR in comparison to comparative batch experiments. The average rates of epoxide production in the RSSDR are about a factor four higher than the batch experiments. In comparison with literature results of similar reaction systems, but different reactors, in particular microreactors, the RSSDR shows values in the same order of magnitude and even outperforms catalyst coated microreactor systems. This study shows that the RSSDR with its very good heat and mass transfer properties allows to significantly intensify epoxidation of fatty acid methyl esters.

Mixing efficiency of a rotor-stator spinning disc extractor

In this work, the mixing efficiency of a rotor-stator spinning disc extractor (RSSDE) is presented. The micromixing efficiency of RSSDE is studied, with the iodide-iodate reaction as working system. The influence of the various operating conditions (e.g. rotational speed, liquid viscosity, volume flow rate, concentration of acid and rotor-stator distance) on micromixing efficiency (characterized by segregation index XS) is investigated. It is found that the XS decreases with the rise of rotational speed, the reduction of rotor-stator distance and the concentration of acid and liquid viscosity. Based on the incorporation model, the estimated micromixing times are in the range of 10−5–10−4 s, which is less than that of other tank mixing and rotating devices. In addition, the residence time of liquid in the rotor-stator cavity is researched to describe the effect of independent variables, like rotational speed, volumetric flow rate, rotor-stator distance, and liquid viscosity, with the help of electrical conductance technique. Besides, the corresponding correlation is also established to predict the residence time. The calculation result shows good coincidence with the experimental data, with a deviation within 20%.

CFD simulation of single-phase heat transfer in a rotor-stator spinning disc reactor

A computational fluid dynamics (CFD) study on hydrodynamics and heat transfer in a rotor-stator spinning disc reactor (RSSDR), an inventive reactor technology engineered within the frame of process intensification, was performed with OpenFOAM®. This allows the investigation of locally resolved temperature profiles and heat transfer coefficients in the reactor gap, which is experimentally difficult for RSSDRs with small dimensions, while keeping computational costs low. The retrieved radial and tangential velocity and temperature profiles are in agreement with literature. Local stator-side heat transfer coefficients were determined, which increase with higher disc speeds and with increasing throughputs. Area-averaged heat transfer coefficients across the reactor gap were calculated and validated against experimental results performed on the setup simulated in this study; the numerical and experimental data are in qualitative agreement. This study presents the possibility to characterize an RSSDR in terms of hydrodynamics and heat transfer properties by means of a two-dimensional axisymmetric geometry and Reynolds-averaged Navier-Stokes (RANS) turbulence modeling in OpenFOAM®. Expensive measurements, which are difficult to perform particularly for RSSDRs with small dimensions, could thus be avoided, simulating industrial applications at the conditions of interest and designing the RSSDR setup accordingly.

Liquid-liquid extraction in a novel rotor-stator spinning disc extractor

Abstract This work describes a novel rotor-stator spinning disc extractor (RSSDE), which shows high efficiency of liquid-liquid mass transfer and rapid separation of mixed phases in comparison to conventional extractors. Extraction of phosphoric acid from an aqueous phase to an organic phase was selected as the experiment system. The influence of rotational disc speed (R), volumetric flow rate (Q), and rotor-stator distance (H) on extraction efficiency (η) and volumetric mass transfer coefficient (KLa) are investigated in an RSSDE with a spiral-grooved rotor disc or smooth rotor disc. The results show that the maximum value of η is 98.8% under optimized conditions. η increases with increasing R and decreases with increasing both Q and H. KLa increases as both the increase of R and Q and decreases as the increase of H. The maximum value of KLa is nearly 10 times higher than for a rotating disc column. The mass transfer performance of the spiral-grooved rotor disc is superior to the smooth rotor disc. Correlations of the main parameters such as angular velocity (ω), Q, and H on η and KLa for an RSSDE with both the spiral-grooved rotor disc and the smooth rotor disc are presented. The calculation result shows good coincidence with experimental data.

Convective mixing of miscible liquids in a rotor-stator spinning disk reactor

Convective mixing of two miscible liquids injected into a rotor-stator spinning disk reactor (RS-SDR) has been studied using an LIF technique and CFD simulations. The fluids are ammonia water and fluorescein ammonia water solutions. The RS-SDR has a rotor 100 mm in diameter and a thin circular cavity 0.10–0.15 mm in height between the rotor and stator. Laminar flow conditions for rotation speeds up to 120 rpm and total flow rates up to 8 mL/min are considered. The fluorescein solution is injected from the second off-center hole into the cavity filled with the ammonia water supplied from the central hole. The LIF technique visualizes a spiral streak pattern formed downstream of the second injection hole. This streak pattern is analyzed to calculate the local mixedness of the two fluids. It is determined that the mixedness increases for lower flow rates, while it is less sensitive to rotation speed and cavity height. The CFD simulations indicate that the spiral streak pattern is deformed and stretched in the radial direction to form a densely layered structure of the two fluids. The development of the mixedness along the streak pattern is correlated well with Reinlet/Recavity, where Reinlet and Recavity are the Reynolds numbers for the injected flow and the azimuthal flow in the cavity, respectively. This Reynolds number ratio is shown to be related to the Rossby number and the position and radius of the second injection hole. The proposed correlation is based on a linear combination of injection mixing and rotation mixing. The mixedness decreases with Reinlet/Recavity because the injection mixing decreases with Reinlet while the rotation mixing increases with Recavity.

Micromixing in a Rotor-Stator Spinning Disc Reactor.

This paper presents the micromixing times in a rotor–stator spinning disc reactor. Segregation indices are obtained at different rotational speeds performing the Villermaux–Dushman parallel-competitive reaction scheme. Consequently, the corresponding micromixing times are calculated using the engulfment model, while considering the self-engulfment effect. It was found that the segregation index decreases with an increasing disc speed. Furthermore, for the investigated operational conditions, the estimated micromixing times are in the range of 1.13 × 10–4 to 8.76 × 10–3 seconds, in agreement with the theoretical dependency on the energy dissipation rate of ε–0.5. In a rotor–stator spinning disc reactor it is thus possible to further continue the theoretical trend of decreasing micromixing times with very high levels of energy dissipation rates that are unattainable in traditional types of process equipment.

Numerical Analysis of The Effect of Hydrodynamics and Operating Conditions on Biodiesel Synthesis in a Rotor-Stator Spinning Disk Reactor

AbstractA rotor-stator spinning disk reactor for intensified biodiesel synthesis is described and numerically simulated in the present research. The reactor consists of two flat disks, located coaxially and parallel to each other with a gap ranging from 0.1 mm to 0.2 mm between the disks. The upper disk is located on a rotating shaft while the lower disk is stationary. The feed liquids, triglycerides (TG) and methanol are injected into the reactor from centres of rotating disk and stationary disk, respectively. Fluid hydrodynamics in the reactor for synthesis of biodiesel from TG and methanol in the presence of a sodium hydroxide catalyst are simulated, using convection-diffusion-reaction multicomponent transport model with the CFD software ANSYS©Fluent v. 13.0. Effect of operating conditions on TG conversion is particularly investigated. Simulation results indicate that there is occurrence of back flow close to the stator at the outlet zone. Small gap size and fast rotational speed generally help to intensify mixing among reagents, and consequently enhance TG conversion. However, increasing rotational speed of spinning disk leads to more backflow, which decreases TG conversion. Large flow rate of TG at inlet is not recommended as well because of the short mean residence time of reactants inside the reactor.

A new hydrate based process for drying liquids

We present a novel process for drying chlorine by formation of a clathrate hydrate. Liquid chlorine is dried in a rotor-stator spinning disc (RSSD) heat exchanger, which has heat transfer coefficients up to 10kW/m2/K, independent of the flow rate. Benefits of this novel drying process are (1) compactness of the spinning disc heat exchanger, minimizing material investments, (2) blocking of the equipment by the adhesive hydrates is prevented by the rotation, and (3) no chlorine contamination by drying agents, e.g., sulfuric acid or zeolite. Batch and RSSD experiments were performed with dichloromethane as a model compound for liquid chlorine. Lower crystallization temperatures result in shorter induction times of the hydrate formation and thus faster water removal rates. Higher mass transfer rates at higher rotation speeds have the same effect. The results show that the RSSD heat exchanger facilitates an elegant, energy-efficient water removal process that can be applied to removal of trace amounts of water from hydrate forming liquids.