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Static Mixer (static + mixer)
Selected AbstractsAn analysis of liquid CO2 drop formation with and without hydrate formation in static mixersAICHE JOURNAL, Issue 10 2010Hideo Tajima Abstract The formation process of CO2 drops in various types of Kenics Static Mixers was analyzed from the perspective of energy dissipation in the mixer, focusing on the formation of drop surfaces. Experimental studies on CO2 drop formation were conducted under varying temperatures, pressure, and flow rates, with and without hydrate formation. Analysis of the CO2 drop size and distribution at several locations within the static mixer was conducted, as of pressure drop in the mixer, to determine dissipation energies. In all the experimental conditions, by considering the surface energy for hydrate formation, the energy required for the formation of CO2 drops correlated well with total energy dissipation by mixer flow, which is represented by a pressure drop along the mixer. This process has important applications to the formation of liquid CO2 for ocean disposal as a countermeasure to global warming. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Continuous process for production of hydrogenated nitrile butadiene rubber using a Kenics® KMX static mixer reactorAICHE JOURNAL, Issue 11 2009Chandra Mouli R. Madhuranthakam Abstract A continuous process for hydrogenating nitrile butadiene rubber (NBR) was developed and its performance was experimentally investigated. A Kenics® KMX static mixer (SM) is used in the process as a gas,liquid reactor in which gaseous hydrogen reacts with NBR in an organic solution catalyzed by an organometallic complex such as an osmium complex catalyst. The Kenics® KMX SM was designed with 24 mixing elements with 3.81 cm diameter and arranged such that the angle between two neighboring elements is 90°. The internal structure of each element is open blade with the blades being convexly curved. The dimensions of the SM reactor are: 3.81 cm ID 80 S and 123 cm length and was operated cocurrently with vertical upflow. The NBR solutions of different concentrations (0.418 and 0.837 mol/L with respect to [CC]) were hydrogenated by using different concentrations of the osmium catalyst solution at various residence times. The reactions were conducted at a constant temperature of 138°C and at a constant pressure of 3.5 MPa. From the experimental results, it is observed that a conversion and/or degree of hydrogenation above 95% was achieved in a single pass from the designed continuous process. This is the first continuous process for HNBR production that gives conversions above 95% till date. Optimum catalyst concentration for a given mean residence time to achieve conversions above 95% were obtained. Finally, a mechanistic model for the SM reactor performance with respect to hydrogenation of NBR was proposed and validated with the obtained experimental results. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Analysis and optimization of low-pressure drop static mixersAICHE JOURNAL, Issue 9 2009Mrityunjay K. Singh Abstract Various designs of the so called Low-Pressure Drop (LPD) static mixer are analyzed for their mixing performance using the mapping method. The two types of LPD designs, the RR and RL type, show essentially different mixing patterns. The RL design provides globally chaotic mixing, whereas the RR design always yields unmixed regions separated by KAM boundaries from mixed regions. The crossing angle between the elliptical plates of the LPD is the key design parameter to decide the performance of various designs. Four different crossing angles from 90° to 160° are used for both the RR and RL designs. Mixing performance is computed as a function of the energy to mix, reflected in overall pressure drop for all designs. Optimization using the flux-weighted intensity of segregation versus pressure drop proves the existence of the best mixer with an optimized crossing angle. The optimized angle proves to be indeed the LLPD design used in practice: the RL-120 with , = 120°, although RL-140 , = 140° performs as good. Shear thinning shows minor effects on the mixing profiles, and the main optimization conclusions remain unaltered. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] NETmix®, a new type of static mixer: Modeling, simulation, macromixing, and micromixing characterizationAICHE JOURNAL, Issue 9 2009Paulo E. Laranjeira Abstract NETmix® is a new technology for static mixing based on a network of chambers connected by channels. The NETmix® model is the basis of a flow simulator coupled with chemical reaction used to characterize macro and micromixing in structured porous media. The chambers are modeled as perfectly mixing zones and the channels as plug flow perfect segregation zones. A segregation parameter is introduced as the ratio between the channels volume and the whole network volume. Different kinetics and reactants injection schemes can be implemented. Results show that the number of rows in the flow direction and the segregation parameter control both macro and micromixing, but the degree of micromixing is also controlled by the reactants injection scheme. The NETmix® model enables the systematic study of micromixing and macromixing for different network structures and reaction schemes, enabling the design of network structures to ensure the desired yield and selectivity. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Design modifications to SMX static mixer for improving mixingAICHE JOURNAL, Issue 1 2006Shiping Liu Abstract Laminar mixing in SMX static mixers and the effect of geometry on mixing are studied using computational fluid dynamics. A frame-indifferent parameter is used to classify the flow types in the SMX mixer. All three typical flows (simple shear, pure elongation, and squeezing) appear within the flow field of the SMX mixer. The strain rate distribution in the SMX mixer is observed to be very nonuniform. A mixing element with 10 crossbars shows the best mixing quality, followed closely by the standard SMX mixing element with eight crossbars. The improved designs of the mixing element increase the average and peak strain rate, and provide a more uniform strain rate distribution and faster mixing rate compared to those of the standard SMX mixer. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Continuous pilot plant,scale immobilization of yeast in ,-carrageenan gel beadsAICHE JOURNAL, Issue 7 2004C. Decamps Abstract A novel continuous two-phase dispersion process was developed to produce ,-carrageenan gel microspheres, using static mixers. It was shown that yeast-loaded carrageenan beads, with controlled diameter and tight size distribution, can be produced on a continuous basis, in a scalable mixer, at production rates appropriate to both pilot plant,scale and, potentially, industrial-scale operations. Immobilized yeast are intended to be used in continuous brewing operations. The effects of the static mixer diameter (D), the number of mixing elements (Ne), the fluid linear velocity (V), and the volumetric fraction (,) of ,-carrageenan, on the mean diameter and size distribution of the resulting gel microspheres, were studied. Image analysis showed that mean diameter was strongly influenced by the average linear fluid velocity through the mixer, and by the mixer diameter. The number of mixer elements and the mixer diameter governed bead size dispersion. A productivity of 10 L h,1 of beads was attained using a 1.27-cm-diameter static mixer. Because the productivity is proportional to the mixer diameter squared, this process, although suited for the production of small-size beads (down to 50 ,m), would be technically and economically feasible for a large industrial immobilization process. However, because the coefficient of variability increased with mixer diameter, and thus with scale-up, operational improvements are suggested, such as the use of smaller-diameter mixers operating in parallel, to reduce the size dispersion. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1599,1605, 2004 [source] Using a modified shepards method for optimization of a nanoparticulate cyclosporine a formulation prepared by a static mixer techniqueJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2008Dionysios Douroumis Abstract An innovative methodology has been used for the formulation development of Cyclosporine A (CyA) nanoparticles. In the present study the static mixer technique, which is a novel method for producing nanoparticles, was employed. The formulation optimum was calculated by the modified Shepard's method (MSM), an advanced data analysis technique not adopted so far in pharmaceutical applications. Controlled precipitation was achieved injecting the organic CyA solution rapidly into an aqueous protective solution by means of a static mixer. Furthermore the computer based MSM was implemented for data analysis, visualization, and application development. For the optimization studies, the gelatin/lipoid S75 amounts and the organic/aqueous phase were selected as independent variables while the obtained particle size as a dependent variable. The optimum predicted formulation was characterized by cryo-TEM microscopy, particle size measurements, stability, and in vitro release. The produced nanoparticles contain drug in amorphous state and decreased amounts of stabilizing agents. The dissolution rate of the lyophilized powder was significantly enhanced in the first 2 h. MSM was proved capable to interpret in detail and to predict with high accuracy the optimum formulation. The mixer technique was proved capable to develop CyA nanoparticulate formulations. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:919,930, 2008 [source] Torque-rheometry investigation of model transreactions involving condensation polymers.POLYMER ENGINEERING & SCIENCE, Issue 2 2006The chemical transformations taking place when poly(ethylene terephthalate) (PET) or poly(ethylene naphthalate) (PEN) are blended in the melt with different low molar mass substances containing hydroxyl, carboxyl, or amine functional groups have been investigated as models of the transreactions, undergone by the polyesters in reactive blending operations. The polyester molecular weight changes caused by the alcoholysis, acidolysis, aminolysis, and esterolysis reactions have been monitored by torque-rheometry, using a Brabender Plasticorder static mixer. The degradation of the polyesters by hydrolysis was also studied, under similar conditions, by the addition of a water-releasing substance (wet polyamide-6), and was shown to occur quite rapidly, although most of the added water was lost by flash vaporization caused by the high temperature of the polyester melt. It has been shown that the rate constants of the reactions leading to breakage of the inner ester bonds of the polyester macromolecules decrease in the following order: aminolysis (with aliphatic amines, either primary and secondary) > alcoholysis (with aliphatic alcohols) , hydrolysis > acidolysis (with aromatic acids) , acidolysis (with aliphatic acids) , aminolysis (with aromatic amines) > alcoholysis (with phenols) , esterolysis. POLYM. ENG. SCI. 46:139,152, 2006. © 2005 Society of Plastics Engineers [source] Homogeneity of multilayers produced with a static mixerPOLYMER ENGINEERING & SCIENCE, Issue 1 2001J. C. Van Der Hoeven A multiflux static mixer can be used to produce multilayered structures. The flow is repeatedly cut, stretched and stacked by mixing elements in the channel of such a device. In the standard design, however, the obtained layer thicknesses are inhomogeneous. The causes for the multiflux static mixer's deviation from ideal behavior are identified by 3D numeical simulations as unequal pressure drops in the separating flows. Changes in the arrangements of the elements are proposed and their effects are verified by simulations and experiments. A significant improvement of the layer homogeneity is achieved by introducing additional elements with separatings walls at the inlets and at the outlets of the mixing elements. [source] An analysis of liquid CO2 drop formation with and without hydrate formation in static mixersAICHE JOURNAL, Issue 10 2010Hideo Tajima Abstract The formation process of CO2 drops in various types of Kenics Static Mixers was analyzed from the perspective of energy dissipation in the mixer, focusing on the formation of drop surfaces. Experimental studies on CO2 drop formation were conducted under varying temperatures, pressure, and flow rates, with and without hydrate formation. Analysis of the CO2 drop size and distribution at several locations within the static mixer was conducted, as of pressure drop in the mixer, to determine dissipation energies. In all the experimental conditions, by considering the surface energy for hydrate formation, the energy required for the formation of CO2 drops correlated well with total energy dissipation by mixer flow, which is represented by a pressure drop along the mixer. This process has important applications to the formation of liquid CO2 for ocean disposal as a countermeasure to global warming. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Spectral characterization of static mixers.AICHE JOURNAL, Issue 2 2010The S-shaped micromixer as a case study Abstract We investigate the steady-state performance of a planar micromixer composed of several S-shaped units. Mixing efficiency is quantified by the decay of the scalar variance downstream the device for generic feeding conditions. We discuss how this decay is controlled by the spectral properties of the advection-diffusion Floquet operator, , that maps a generic scalar profile at the inlet of a single unit into the corresponding profile at the unit outlet section. Two advantages characterize the Floquet operator approach ,(i) it allows to analyze an arbitrarily long device and (ii) it provides a quantitative assessment of mixing efficiency that is independent of the feeding conditions and that depends solely on the interaction between advection and diffusion. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Analysis and optimization of low-pressure drop static mixersAICHE JOURNAL, Issue 9 2009Mrityunjay K. Singh Abstract Various designs of the so called Low-Pressure Drop (LPD) static mixer are analyzed for their mixing performance using the mapping method. The two types of LPD designs, the RR and RL type, show essentially different mixing patterns. The RL design provides globally chaotic mixing, whereas the RR design always yields unmixed regions separated by KAM boundaries from mixed regions. The crossing angle between the elliptical plates of the LPD is the key design parameter to decide the performance of various designs. Four different crossing angles from 90° to 160° are used for both the RR and RL designs. Mixing performance is computed as a function of the energy to mix, reflected in overall pressure drop for all designs. Optimization using the flux-weighted intensity of segregation versus pressure drop proves the existence of the best mixer with an optimized crossing angle. The optimized angle proves to be indeed the LLPD design used in practice: the RL-120 with , = 120°, although RL-140 , = 140° performs as good. Shear thinning shows minor effects on the mixing profiles, and the main optimization conclusions remain unaltered. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Design modifications to SMX static mixer for improving mixingAICHE JOURNAL, Issue 1 2006Shiping Liu Abstract Laminar mixing in SMX static mixers and the effect of geometry on mixing are studied using computational fluid dynamics. A frame-indifferent parameter is used to classify the flow types in the SMX mixer. All three typical flows (simple shear, pure elongation, and squeezing) appear within the flow field of the SMX mixer. The strain rate distribution in the SMX mixer is observed to be very nonuniform. A mixing element with 10 crossbars shows the best mixing quality, followed closely by the standard SMX mixing element with eight crossbars. The improved designs of the mixing element increase the average and peak strain rate, and provide a more uniform strain rate distribution and faster mixing rate compared to those of the standard SMX mixer. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Continuous pilot plant,scale immobilization of yeast in ,-carrageenan gel beadsAICHE JOURNAL, Issue 7 2004C. Decamps Abstract A novel continuous two-phase dispersion process was developed to produce ,-carrageenan gel microspheres, using static mixers. It was shown that yeast-loaded carrageenan beads, with controlled diameter and tight size distribution, can be produced on a continuous basis, in a scalable mixer, at production rates appropriate to both pilot plant,scale and, potentially, industrial-scale operations. Immobilized yeast are intended to be used in continuous brewing operations. The effects of the static mixer diameter (D), the number of mixing elements (Ne), the fluid linear velocity (V), and the volumetric fraction (,) of ,-carrageenan, on the mean diameter and size distribution of the resulting gel microspheres, were studied. Image analysis showed that mean diameter was strongly influenced by the average linear fluid velocity through the mixer, and by the mixer diameter. The number of mixer elements and the mixer diameter governed bead size dispersion. A productivity of 10 L h,1 of beads was attained using a 1.27-cm-diameter static mixer. Because the productivity is proportional to the mixer diameter squared, this process, although suited for the production of small-size beads (down to 50 ,m), would be technically and economically feasible for a large industrial immobilization process. However, because the coefficient of variability increased with mixer diameter, and thus with scale-up, operational improvements are suggested, such as the use of smaller-diameter mixers operating in parallel, to reduce the size dispersion. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1599,1605, 2004 [source] Mischen und organische Reaktionen in der chemischen Industrie,CHEMIE-INGENIEUR-TECHNIK (CIT), Issue 5 2004T. Bayer Dr. Abstract Mischvorgänge sind eine der wichtigsten Grundoperationen in der chemischen Industrie. Neben normalen Rührkesseln werden oft auch statische Mischer verwendet. Seit einigen Jahren erfreut sich aber auch die Mikrotechnik einer wachsenden Aufmerksamkeit in der Prozessentwicklung. Sie wird , insbesondere in der chemischen Verfahrenstechnik , zu einem wertvollen Werkzeug für Forschung und Entwicklung. Dabei wird die Mikroreaktionstechnik sowohl für die Entwicklung neuer Prozesse als auch bei der Optimierung existierender Verfahren angewandt. Mikrostrukturierte Mischer und Wärmeübertrager werden eingesetzt, um das Potenzial von chemischen Reaktionen , ohne Wärme- oder Stofftransportlimitierungen , zu untersuchen und zu optimieren. Auch erste Anwendungen über den Labormaßstab hinaus sind bekannt. Mixing and Organic Reactions in the Chemical Industry Mixing is one of the most important unit operations in the chemical industry. In addition to classical mixed vessels, static mixers are often used too. However, for several years now, micro technology is becoming more and more common practice in process development. Especially in chemical engineering micro technology becomes a very valuable tool for research and development. Micro reaction technology is used for the optimization of existing and the development of new processes. Microstructured mixer and heat exchangers are used to overcome heat and mass transfer limitations to show the potential of a chemical reaction. First examples for the application of micro technology beyond the laboratory scale are already know. [source] Mischer mit mikrostrukturierten Folien für chemische ProduktionsaufgabenCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 5 2004B. Werner Abstract Seit etwa 10 Jahren beschäftigt sich die Institut für Mikrotechnik Mainz GmbH (IMM) mit der Nutzung von Mikrostrukturen im Bereich der Mikroverfahrenstechnik. Deren Vorteile , effizienterer Wärmeaustausch und Massentransport , bewirken u.,a. Steigerung von Ausbeute und Selektivität bei gleichzeitiger Ressourcenschonung. Die Entwicklung von mikrostrukturierten Mischern war dabei ein Schlüssel zu verbesserten Feinchemikaliensynthesen sowie zur Herstellung von Dispersionen, Cremes, Schäumen und Emulsionen. Bislang waren diese mikrostrukturierten Mischer im Wesentlichen auf Labor- oder bestenfalls Pilotanlagen-Maßstab festgelegt , typische Maximalflussraten lagen bei 2,, 100,L/h für wasserähnliche Fluidsysteme. Mit der Einführung der StarLaminatoren StarLam300 und StarLam3000, konnte diese Grenze jetzt auf weit über 300,L/h bis in den m3/h-Bereich angehoben werden. Beide Apparate zeigen gute Mischgüten bei hohen Flüssen, die durchaus an die sehr guten Werte von bisher bekannten Niederdurchsatz(L/h)-Mikromischer heranreichen. Damit ist eine Kontinuität von ,wirklichen" Mikromischern über die hier beschriebenen Hochdurchsatz-Tools bis zu statischen Mischern mit noch höheren Durchsätzen gegeben. Eine Klassifikation der Mischeffizienz nach dem Leistungseintrag bestätigt ebenso diese Kontinuität. Mixers with Microstructured Foils for Chemical Production Purposes Since about 10 years the Institut für Mikrotechnik Mainz GmbH (IMM) is engaged with the application of microstructures for chemical micro process engineering. Their advantages , more efficient heat exchange and mass transport , lead to, among other things, an increase in yield and selectivity even while saving resources. The development of microstructured mixers thereby played a key role for carrying out advanced syntheses of fine chemicals as well as for the generation of dispersions, creams, foams, and emulsions. So far, microstructured mixers were mainly limited for laboratory-scale or at best pilot plant-scale , typical maximum flow rates were from 2 , 100 L/h for watery fluid systems. With the introduction of the StarLaminators StarLam300 and StarLam3000 this barrier could be lifted far beyond 300 L/h up to the m3/h domain. Both apparatus yield at high flow rates a mixing efficiency which reaches the high performance of today's low-capacity (L/h) micro mixers. Therefore, continuity from the "real" micro mixers over the herein described high-throughput tools to conventionally manufactured static mixers with even higher flow rates is given. [source] | ||||||||||