Reactor engineering

Heterogeneous manufacturing processes based on chemical reactions, biochemical transformations and adsorption, which inherently involve both a solid and a liquid phase, are associated with several technical challenges. One of the most difficult issues is achieving contact between the reagents in the two phases – a phenomenon known as mass transfer limitation. The reagents in the liquid phase must be brought to an active site on the solid phase through transport of the liquid medium relative to the solid particle. In absence of any stirring to create convective flow, this transport only takes the form of diffusion, which is a very slow process. The mass transport is therefore increased in laboratories and production facilities by means of a suitably designed reactor.

Reactor types

The traditional and perhaps most common way to deal with mass transport limitations is a stirred tank reactor (STR). In the STR a two-phase slurry of particles in suspension is stirred using an agitator. This generates a convective flow in the reactor which increases the relative transport of the liquid phase and solid particles, bringing reactants together at a higher rate than if left only to diffusion. The agitator also improves the mixing time of the reactor, being the time taken to disperse any concentration gradients in the liquid bulk that arise due to the local generation or removal of chemical species at the reaction sites. However, the STR may cause physical damage to the solid phase as the particles collide with the agitator and each other. These collisions often lead to grinding of the particles, producing fines that are hard to remove and limit the ability to reuse the solid material. For most applications, the STR thus introduces a need for filtration after the reaction is completed.

A gentler treatment takes place in a packed column, also known as a fixed bed reactor (FBR). Here the solid phase is packed in a stationary bed through which the liquid phase is then pumped. Grinding is then eliminated as there is no relative motion between any solid bodies. Still, associated with the FBR is a back pressure that increases with liquid viscosity and flow rate among other parameters. To avoid slow percolation of viscous liquids through the packed bed, powerful pumps and strong particles that can withstand immense pressures are required for operation of FBR.

Rotating bed reactors

A rotating bed reactor (RBR) is a modern alternative to the traditional reactor types. The solid phase is loaded into the RBR and kept in place by filters that allow the liquid medium to pass through. The RBR is rotated within the reaction vessel containing the liquid which then passes through the RBR due to inertial forces. By keeping the solid phase fixed within the RBR it is protected from grinding. The flow rate, controlled by the rotational speed, can also become many times greater than in a typical column of corresponding volume. This leads to significantly greater reaction rates in mass transport limited cases. Moreover, each fluid parcel will have many passages through the RBR, providing the reagents with plenty of time to react with the solid phase in applications limited by chemical kinetics. Since the solid phase is contained within the RBR it may also be regenerated or reused in-situ for another reaction step without any time-consuming filtration in between.

Application 1012
An externally connected system for large scale heterogeneous downstream processing

Time lapse video illustrating how an externally connected rotating bed reactor (RBR) can pump and process large liquid volumes by the convective flow created by the spinning RBR. The concept enables handling of volumes at least 10-100 times larger than the external vessel, thus facilitating installation of RBR technology into existing plant equipment.  Keywords: Activated carbon, Continuous flow, Decolouration, Organic molecules, Seamless scaleup, Technology

Application 1007
Automated semi-continuous batch processing system with rotating bed reactor

Video showing the principle of an automated rotating bed reactor system capable of filling a solution, neutralizing it by ion exchange and draining it. By microcomputer control, unattended semi-continuous batch processing was accomplished for many cycles until the ion exchanger was completely saturated.  Keywords: Automation, Ion exchange, Seamless scaleup, Technology

Application L1702
CFD modeling of flow and ion exchange kinetics in a rotating bed reactor system

A rotating bed reactor containing ion exchange beads was modeled in flower-baffled reaction vessels. It was shown that the baffles are vital for reducing surface vortexes and circular flow within the vessel. The authors concluded that the flow rates through the packed bed and reaction rates tend to increase with deeper baffles.   Keywords: Ion exchange, Scientific literature, Simulation, Technology

Application 9005
Chemical Catalysis with MagRBR and EasyMax – Quick and Convenient Suzuki couplings

This application note demonstrates how the combination of a SpinChem MagRBR custom-filled with heterogenous Pd(II)-catalyst and the controlled conditions in a Mettler-Toledo EasyMax™ 102 Advanced Synthesis Workstation allows for quick and convenient generation of C-C coupled products.  Keywords: Chemical catalysis, Easy handling, Mettler-Toledo

Application 1035
Column vs RBR

A performance comparison between a column (fixed bed reactor) and rotating bed reactor (RBR) for de-ionizing 1000 L of tap water. Using best-in-class standard protocols for both technologies, we tested which technology could de-ionize to a desired endpoint conductivity value the quickest. The result show that the RBR is significantly faster, reaching 3.7 times faster a conductivity level of 0.15 µS/cm compared to the column.  Keywords: Cleantech, Deionization, Fast reaction, Technology  

Application 1024
Comparing rotating bed reactor and fixed bed reactor for adsorption purification

Comparison of rotating bed reactor (RBR) technology and fixed bed reactor (FBR) column during activated carbon decolourization. The more efficient use of the adsorbent with a SpinChem® RBR enabled completion of the process within 40% of the time at the same material amount or allowed reduction to 50% material while still being able to finish the process within the same time as the FBR.  Keywords: Activated carbon, Decolouration, Fast reaction, Organic molecules, Purification, Technology  

Application 1006
Comparison of reaction speed with rotating bed reactor and stirred tank reactor

Video revealing the efficient mass transfer and resulting shorter reaction time with a rotating bed reactor (RBR) during ion-exchange neutralization of a base. The reaction with the RBR finished 30% faster and left a completely clear solution without any particles. Keywords: Fast reaction, Ion exchange, Technology

Application 1004
Consequences of viscous solutions on the reaction rate with rotating bed reactors

Log-log plot of how viscosity affects the reaction time for a mass transfer limited reaction at a fixed rotational speed of a rotating bed reactor (RBR). The RBR behaved very predictably and delivered reaction times that increased linearly with reaction media viscosity up to at least 500 mPa·s.  Keywords: Ion exchange, Organic molecules, Technology, Viscous solutions  

Application 1030
Decolourization of highly viscous solutions using a rotating bed reactor and a stirred tank reactor

The performance of a SpinChem® rotating bed reactor (RBR) in the treatment of highly viscous solutions was compared to that of a conventional stirred tank reactor (STR). Both reactor set-ups were used for the extraction of Allura red dye from a glycerol-dye mixture using an ion exchange resin. The RBR removed 10 times the amount of dye in just over 40 % of the time, compared to the STR. This comparison underlines the efficient mixing and clever design of the SpinChem® RBR, as well as the broad spectrum of applications for which this technology is highly relevant.  Keywords: Decolouration, Fast reaction, Ion exchange, Technology, Viscous solutions    

Application L1601
Deconstruction of Nordic hardwood in switchable ionic liquids and acylation of the dissolved cellulose

Valerie Eta, Jyri-Pekka MikkolaCarbohydrate Polymers, 136 (2016) 459-465

Application 1033
Deionizing 7000 L of tap water using the SpinChem® RBR S100

The SpinChem® rotating bed reactor (RBR) S100, with a solid phase capacity of 100 L, was used to deionize 7000 L of tap water. The RBR S100 was operating at 160 rpm and filled with 36.5 L of mixed bed ion exchange resin. The results show that the RBR S100 can efficiently process large liquid volumes. As shown by the successful deionization, the performance of the RBR remains high even when it is partially filled, which proves the extreme robustness of the RBR technology.  Keywords: Ion exchange, Seamless scaleup, Technology  

Application 1021
Demonstration of loading, reaction and unloading in a production scale rotating bed reactor

Video showing how a SpinChem® rotating bed reactor (RBR) for use in 20-300 L vessels was charged with solid particles, used for pH neutralization, drained from reaction liquid and finally emptied from solid phase without opening the RBR. This procedure illustrates one approach to using RBR in production scale equipment without opening the reaction vessel.  Keywords: Easy handling, Ion exchange, Seamless scaleup, Technology

Merry Christmas
Effective extraction of spices for mulled wine production using a rotating bed reactor

Video showing how to promote holiday spirit by seasoning mulled wine using a rotating bed reactor. Assorted spices and sugar were used to transform white wine mixed with a clear liquor into a festive and flavourful Christmas drink. The temperature of the mixture was kept at 70°C and the outside temperature at -6°C, using a heating jacket and a northern latitude, respectively.  Keywords: Behind the scenes

Application 1003
Effective phase-transfer between immiscible liquids and an ion exchange resin

Illustrative video showing how a phenolic colourant is deprotonated and extracted from an organic to an aqueous solvent. Using SpinChem® RBR in a flower-baffled reaction vessel created fine emulsion droplets resulting in effective phase-transfer between the two liquids and the solid phase. Keywords: Immiscible liquids, Ion exchange, Organic molecules, Technology

Application L1401
Enhanced mass transfer upon switchable ionic liquid mediated wood fractionation

Valerie Eta, Ikenna Anugwom, Pasi Virtanen, P. Mäki-Arvelaa, Jyri-Pekka MikkolaIndustrial Crops and Products, 55 (2014) 109-115  Keywords: Scientific literature

Application 1028
Enzyme immobilization screening using magnetic rotating bed reactors

The SpinChem® MagRBR ECR screening kit, pre-packed with Purolite® Lifetech™ resins, was used to screen six different enzyme carrier resins in parallel for the immobilization of lipase CalB. Easy sampling and monitoring of the process, together with effortless handling, established the MagRBR as a time and labour efficient screening device. Keywords: Biotransformation, Easy handling, Immobilized enzymes, Rapid screening

Application 1013
Flow rate determination in a connected system with rotating bed reactors

Short video of a coloured dye front moving in a transparent liquid through a pipe connecting an external rotating bed reactor to a larger vessel. The total convective flow rate was calculated to 440 L/h based on linear progression of the dye and assuming steady state turbulent conditions at Reynolds number 7900.  Keywords: Continuous flow, Seamless scaleup, Technology

Application 1029
Effects of channelling on flow rates through rotating bed reactors and fixed bed reactors

The performance and robustness of the SpinChem® rotating bed reactor (RBR) technology was examined and compared to a fixed bed reactor (FBR) using ANSYS Fluent. By means of flow simulations through loosely packed beds, the RBR was found to be extremely robust with respect to the level of packing of the solid phase within, while the FBR was negatively affected by channelling.  Keywords: Easy handling, Simulation, Technology

Application 1016
In situ filling and emptying of rotating bed reactors

Video showing how a SpinChem® rotating bed reactor (RBR) was charged with solid particles, followed by draining and replacing the reaction liquid without escape of solids. Lastly, the solid phase was removed without opening the RBR. This procedure illustrates a concept for automatic handling of solid phases in production scale equipment without opening the reaction vessel.  Keywords: Easy handling, Seamless scaleup, Technology

Brochure
Mass transfer revolutionized

Learn how SpinChem rotating bed reactors (RBR) can eliminate poor mass transfer in heterogeneous reactions during chemical synthesis and biotransformations. Preserve activity and facilitate recycling of solid phases with the RBR. This brochure shows technology and applications.  Keywords: Biotransformation, Brochure, Fast reaction, Immobilized enzymes, Molecular sieve, Preserved activity, Simple cleanup, Synthesis, Technology

Application 1001
Optimizing the rotational speed of rotating bed reactors in baffled reaction vessels

Investigation of how rotational speed influences the efficiency of rotating bed reactors (RBR) for a diversity of processes such as adsorption, neutralization and ammonolysis. It was demonstrated how reaction rates could reach a plateau with the SpinChem® RBR when mass transfer efficiency exceeded reaction speed.   Keywords: Activated carbon, Fast reaction, Immobilized enzymes, Ion exchange, Technology

Application L1703
Reaction engineering of biocatalytic (S)-naproxen synthesis integrating in-line process monitoring by Raman spectroscopy

A traditional stirred tank reactor setup was compared to a rotating bed reactor (RBR) for the biocatalytic synthesis of the anti-inflammatory drug (S)-naproxen. Both setups performed well during five repetitive bathes giving an enantiomeric excess of 99% and an isolated yield of 92%, but the RBR was easier to handle and the authors concluded that “… the rotating bed reactor concept can be regarded as a promising option for industrial applications”. Keywords: Biotransformation, Immobilized enzymes, Organic molecules, Scientific literature

Application 9001
Recycling of Immobilized Enzymes – Simple and Streamlined Biocatalysis

Immobilized catalyst recycling using a SpinChem® rotating bed reactor (RBR) and a Mettler-Toledo EasyMax™ 102 Advanced synthesis workstation. The process proved very time efficient as no filtration steps were needed between cycles, or for the samples extracted for analysis during each run. Washing of the resin between runs was fast, simple and robust, without running the risk of material loss. Keywords: Biotransformation, Immobilized enzymes, Mettler-Toledo, Organic molecules, Preserved activity, Quick recycling

Application 1032
Rotating bed reactor for immobilized enzymatic reactions

Poster on a case study of applying the rotating bed reactor for the lipase-mediated stereoselective acetylation of a racemate amine as a model reaction for the manufacturing of pharmaceutical building blocks. The results showed that enzyme recycling and synthesis scale up was easy to achieve with preserved yield, enantioselectivity and catalytic activity.   Keywords: Biotransformation, Easy handling, Immobilized enzymes, Quick recycling, Seamless scaleup

Application 1025
Rotating bed reactor setup for in situ formation, loading and handling of alginate beads and whole cell encapsulation

Video showing the formation of alginate beads under conditions mimicking whole cell encapsulation. The use of a SpinChem® rotating bed reactor (RBR) allowed easy collection, maturing and washing of the alginate beads. With the RBR setup, it was possible to immediately continue with filling of the reaction substrate into the same vessel, thus reducing the number of handling steps and facilitating bead recycling. The beads showed no signs of physical wear after use in the RBR.   Keywords: Alginate, Biotransformation, Easy handling, One-pot multistep, Technology

Application 1010
Rotating bed reactors completely avoid grinding of molecular sieves

Photos showing how grinding caused by stirring of molecular sieves can be completely avoided by using a rotating bed reactor (RBR). Molecular sieves contained in a RBR for a 200 mL vessel can theoretically hold 0.23 moles of water. This allows synthesis of product in the range of 100 gram by ester condensation or drying of 25 litres of analytical grade organic solvent. Keywords: Easy handling, Molecular sieve, Purification, Simple cleanup, Synthesis, Technology, Water

Application 1036
Screening of activated carbon using the SpinChem® RBR S2

In co-operation with ZHAW, two students screened various types and sizes of activated carbon using the SpinChem® RBR S2. Five different carbons were screened by decolorizing solutions of methylene blue in distilled water. The decolorization process was monitored using inline UV-Vis spectrometry (PAT). The results show the importance of choosing the correct media for your application. In this case of activated carbon, the source and type of the activation was shown to have a major impact on performance.  Keywords: Activated carbon, Decolouration, Fast reaction, Rapid screening, Technology

Application 9002
Screening of Immobilized Enzymes – Fast and Convenient Reaction Optimization

The stable reaction environment in the EasyMax™ 102 Advanced synthesis workstation and the high flow rates through the SpinChem® RBR allowed for quick and convenient screening of different immobilized lipases to find the enzyme most suitable for further reaction optimization.   Keywords: Biotransformation, Immobilized enzymes, Mettler-Toledo, Organic molecules, Rapid screening

Application 1027
Screening of immobilized lipases using magnetic rotating bed reactors

Six different immobilized lipases were screened in parallel for the esterification of lauric acid into propyl laurate using the pre-packed SpinChem® MagRBR Lipase screening kit. The process proved fast and simple, as efficient sampling and monitoring of the process was achieved without filtration steps, by keeping the immobilized catalyst confined inside the MagRBR.   Keywords: Biotransformation, Easy handling, Immobilized enzymes, Organic molecules, Rapid screening

Application 1020
Simulation of flow patterns around a rotating bed reactor in a flower baffled reaction vessel

Computational fluid dynamics simulations is an important tool in the optimization of geometries during development of SpinChem® rotating bed reactor (RBR) products. The image shows velocity vectors in a cross section of the flow around a SpinChem® RBR, in a flower baffled reaction vessel, simulated using ANSYS Fluent software under typical laboratory conditions.  Keywords: Behind the scenes, Simulation, Technology

Application 1009
Simultaneous extraction of two dyes selectively onto different resins

Video illustrating how a mixture of red and blue dyes with different chemical properties can be selectively extracted onto different adsorbents within the same run using a rotating bed reactor (RBR). The dyes were separated based on ionic and hydrophobic interactions, respectively.  Keywords: Cleantech, Decolouration, Extraction, Ion exchange, One-pot multistep, Organic molecules, Polymeric resin, Technology

Application 9003
Simultaneous Selective Decolouration – Illustrating a Concept for Cascade Reactions

Two dyes were selectively extracted onto different adsorbents within the same run using a SpinChem® rotating bed reactor (RBR) and an EasyMax™ 102 Advanced synthesis workstation. This experiment illustrates performing cascade reaction for one-pot multi-step synthesis.  Keywords: Cleantech, Decolouration, Extraction, Ion exchange, One-pot multistep, Organic molecules, Polymeric resin, Technology

Application 1022
Transfer hydrogenation with catalyst recycling in a rotating bed reactor

Convenient transfer hydrogenation catalysed by palladium-containing beads was performed using a SpinChem® rotating bed reactor (RBR). The set-up resulted in high product conversions throughout more than 10 consecutive batches without any need for filtration to recycle the catalyst.  Keywords: Easy handling, Organic molecules, Palladium on carbon, Quick recycling, Synthesis

Application 9004
Treatment of Viscous Solutions – Simple Extraction and In-line Monitoring

Blue dye was removed from a highly viscous liquid using a SpinChem® RBR S2 in an EasyMax™ 102 Advanced Synthesis Workstation. Monitoring of the reaction was easily recorded as no freely suspended ion exchange resin beads or resin debris interfered with the readings. This demonstrates that the RBR technology is extremely well suited for in-line monitoring. The viscosity of the solution was determined to ca 230 cP at 25°C, showing that it is possible to absorb dye even from a highly viscous solution.  Keywords: Decolouration, Extraction, Ion exchange, Mettler-Toledo, Viscous solutions

Application 1037
In-tank deployment of large scale rotating bed reactor

To further demonstrate the use of RBR:s at process scale, a decolorization using ion exchange resin was performed at 7500 L scale. An RBR S14 was filled with strongly acidic cationic resin NRW1160 from Purolite and used to remove blue dye from an aqueous solution in a stainless steel tank of 7500 L volume. The solid-to-liquid ratio is a fraction of percent, showing the efficiency of the RBR technique for convectional mass-transfer and global mixing. The RBR was spun at 340 rpm while the transmittance at 663 nm was monitored for ca 4 h at which point the transmittance had recovered the baseline value for colorless de-ionized water.   Keywords: Ion exchange, Cleantech, Nuclear, Scale-up  

Application 1039
Remediation of wastewater stored in High Integrity Container

The versatility of the ProRBR IBC add-on (picture below) was demonstrated by mounting it on a high-integrity container (HIC) (picture above) and running a sample reaction. The ProRBR IBC add-on can be placed on most reasonably stable supports. In this case, the RBR add-on was placed over the HIC opening by support of a common construction scaffold. A common ion-exchange reaction, de-ionization by 7 L of mixed-bed resin to 3000 L of municipal water, was carried out to measure the performance. The ion concentration/ conductivity was halved after ca 30 min and after 2 h it was down to our LOQ.

Application 1040
The importance of baffles in a reactor vessels

baffle (noun) : a device (such as a plate, wall, or screen) to deflect, check, or regulate flow or passage (as of a fluid, light, or sound) Can you use a rotating bed reactor (RBR) in any type of vessel? Absolutely. Would the performance be higher with baffles in the vessel? Definitively. A vortex, which forms due to the rotation of an agitator, is detrimental to the mixing in a reactor vessel. If the agitator is a rotating bed reactor, it also disrupts the flow through the RBR. Baffles are features in the reactor vessel that break the circulating flow pattern, preventing vortex formation and improving overall mixing. The importance of baffles has long been established for stirred tank reactors with agitation by impellers, and baffling is equally important for vessels with an RBR installed. You don't need to take our word for it; customers that have investigated the effect of baffling on their mass-transfer limited reactions have found the same result. The most recent data comes from research at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB. They started out with the RBR S3 in a smooth glass vessel. After observing a deep vortex, drawn down into the RBR, and the resulting disappointing performance, one simple flat-blade baffle was installed. The performance for the enzymatic reaction was quantified with and without the flat-blade baffle, and the result is presented in the figure below. As seen in the data, installing one simple baffle resulted in a doubled yield at each time point on average. The double-walled glass vessels (V2 and V3) that SpinChem offer are custom-made to fit the RBR S2 and S3 respectively. The vessels have structured inner glass walls that serve as "flower-shaped" baffles, which do not take up the same space as traditional flat-blade baffles. This minimizes the required volume of reaction medium, and maximizes mixing performance.   Some non-baffled vessels perform as if they had flow breakers installed, just through the shape of their vessel walls. For instance, any non-round geometry such as rectangular IBC-tanks may provide satisfactory mixing and prevention of a deep vortex forming. On benchtop scale, the round beaker is appealing with its simplicity, but a baffled reaction vessel will yield much better performance. If you have more questions about this contact us.

Application L2117
Multi‐enzyme cascade reaction in a miniplant two‐phase‐system : Model validation and mathematical optimization

In the American Institute of Chemical Engineers, AIChE Journal, the authors of this paper highlights the use of Rotating Bed Reactor (RBR) with two different immobilized enzymes at the same time in a cascade reaction. In the flow chart above of the miniplant consisting of a continuously stirred tank reactor (CSTR) equipped with an RBR (highlighted in orange) (a), a buffer tank (b), an extractive centrifuge (c) and a fixed bed reactor (d)  In the reaction scheme the complete multi-enzyme cascade is shown with the two enzymes placed in the RBR is highlighted. If you would like to get in contact with us give us a call or fill in the form.

Treatment of 7.5 m3 with a 50L Plug-in system

A small rotating bed reactor (RBR) system deployed in an external loop to the customer’s regular reaction vessel. Even though RBR technique has been identified as offering advantages for a particular process, deploying it in existing an existing reaction vessel may prove difficult for practical reasons. This is were “plug-in” mode deployment of the RBR can offer a solution. The RBR and associated vessel is attached in an external loop by inlet and outlet connections to the regular vessel. The “plug-in” RBR system is typically small compared to the regular vessel. Alternatively, the RBR system can be deployed in a vessel → RBR → 2nd vessel mode. A proof-of-concept demonstration of an RBR in “plug-in” mode by a decolorization. The volume of the “plug-in” vessel is ca 0.7% of the regular vessel it is attached to.

Application 1042
How large liquid volumes can a rotating bed reactor process?

Large volumes of liquid waste will often accumulate at industrial sites. It may be very time-consuming and resource-intensive to adequately treat these waste streams for release, so the problem often compounds over time. The rotating bed reactor (RBR) is a tool for treating very large volumes of liquids; valuable batches of product or problematic liquid waste. In the latter case, the contamination is concentrated to a smaller volume of solid waste, often reducing the mass and volume of the waste many thousands of times. SpinChem will design a treatment system for your individual case and to your requirements. We have the capabilities to build and test complete systems, as well as predict performance using computational models and in-house pilot tests. Legacy waste in the nuclear energy sector, unresolved for many decades, have been cleared for release in weeks after the implementation of a rotating bed reactor. Contact us today for a consultation on your liquid application. To prove the application of an RBR in very large liquid volumes the benchtop model RBR S2 (which normally operates on 120 mL of liquid) was installed in an IBC containing 780 L of water and 400 mg of methylene blue. The RBR was filled with activated carbon and rotated at 800 RPM. The amount of dye in the solution was measured by spectrophotometry. Roughly 90% of the dye was removed in the first 70 hours. The liquid-to-solid ratio was more than 27800(!), and still the RBR homogeneously treated the entire volume. The rotating bed reactor technology was deployed in the nuclear energy sector on a tank containing 90 m3 of water, wherein a contaminant was removed by adsorption. The RBR contained only 14 L of adsorbent at a time, and the 90,000 L of liquid waste was reduced to 57 L of solid waste.

Application 1043
Using a rotating bed reactor in different liquid volumes

Research and development quickly takes new directions, and the requirements on a laboratory may vary with every new project. Limiting yourself to equipment with a narrow scope of conditions and applications may become expensive, since new equipment must be acquired for anything out of scope. With budgets quickly consumed by other projects, the need for new equipment may mean significant delays and a reduced capability to take on emerging opportunities. SpinChem’s rotating bed reactors can be used with any solid phase where the particles are larger than 100 µm, and the range of possible operating conditions is large. From highly viscous solutions to varying temperatures or pressures, the rotating bed reactors are versatile. The rotating bed reactor creates a strong flow of liquid through the solid phase and efficiently mixes the entire liquid volume. This means that the same rotating bed reactor can be deployed in liquids of different volumes. In this example Methylene Blue was dissolved in similar concentrations in four different volumes of water. An RBR S2 was filled with activated carbon and used to decolorize the solutions. The decolorization followed 1st order kinetics (exponential decay), and the reaction rate coefficients were, predictably, found to be inversely proportional to the liquid volume. The time to reach a target concentration was thus simply proportional to the liquid volume. This experiment has demonstrated that a rotating bed reactor can be used in greatly varying liquid volumes, and that the performance easily carries over between scales. With a rotating bed reactor in your lab, you are prepared to try new heterogeneous applications or develop processes like catalysis, adsorption or ion exchange reactions. SpinChem provides rotating bed reactors from laboratory scale to full production for companies in Pharma, Food & Beverage, Nuclear waste management, and many other industries.

Application 1044
Simple scale-up using flexible reactors

Research and development quickly takes new directions, and the requirements on a laboratory may vary with every new project. Limiting yourself to equipment with a narrow scope of conditions and applications may become expensive, since new equipment must be acquired for anything out of scope. With budgets quickly consumed by other projects, the need for new equipment may mean significant delays and a reduced capability to take on emerging opportunities. Many heterogeneous processes (e.g. adsorption or catalysis) are made faster by increasing the solid-to-liquid ratio. Studying scale-up effects can also help to predict full-scale performance. For these reasons it’s wise to invest in equipment that can handle different operating conditions such as liquid volume, solids loading, pH and temperature. The RBR S3 Plus is the most modular rotating bed reactor for laboratory use. Made from two stacked rotating bed reactors, the S3 Plus quickly converts to a single RBR S3 for use with smaller liquid volumes. When used in the dedicated glass reactor system, this yields an operating range of 250 - 1500 mL of liquid and 0 - 140 mL of solids.   This application note investigates the effect of solids loading on the reaction rate of two applications: the adsorption of a dye and a biocatalytic esterification reaction. These two reactions are mass-transport limited and relatively fast. In the first case, an RBR S3 and an RBR S3 Plus were filled with 50 mL and 100 mL respectively of the ion-exchange resin Purolite® NRW1160. Methylene blue was dissolved in water, and the solution was decolorized by spinning an RBR at 600 RPM (reaction conditions in the details below). The results were clear; each case followed 1st order kinetics with a rate constant for the RBR S3 Plus that was twice that of the RBR S3. Note that the solid-to-liquid ratio for the RBR S3 Plus was also twice that of the RBR S3. For the enzymatic esterification, the same rotating bed reactors (RBR S3 and RBR S3 Plus) were filled with 40 mL and 80 mL respectively of the biocatalyst Purolite® immo PS. The rotating bed reactors were used in separate reactions in mixtures of lauric acid, 1-propanol and water. Also in this case the reaction rate was proportional to the solid-to-liquid ratio, yielding twice the productivity with the RBR S3 Plus compared to the RBR S3. The conclusion is that with a rotating bed reactor you are making the most out of the solid-phase. Doubling the amount of catalyst or adsorbent will generally double the reaction rate constant, which makes scaling up straightforward. Contact us today to discuss how we can scale your process.

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