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Microreactor
Terms modified by Microreactor Selected AbstractsCross-Coupling in a Flow Microreactor: Space Integration of Lithiation and Murahashi Coupling,ANGEWANDTE CHEMIE, Issue 41 2010Dr. Aiichiro Nagaki Mit dem Strom schwimmen: Der Einsatz von Palladiumkatalysatoren mit einem Carbenliganden bewirkte eine schnellere Murahashi-Kupplung und ermöglichte deren Kombination mit einem Br-Li-Austausch zwischen ArBr und BuLi in einem Mikroreaktor (siehe Bild). Auf diese Art können zwei verschiedene Arylbromide innerhalb einer Minute verknüpft werden, ohne dass tiefe Temperaturen (,78°C) erforderlich waren. [source] Experimental Investigation and Modeling Approach of the Phenylacetonitrile Alkylation Process in a MicroreactorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2009E. S. Borovinskaya Abstract The application of microreaction technology has the potential to intensify chemical processes. It is therefore of great interest to investigate the operating efficiency of a multiphase process such as the alkylation of phenylacetonitrile in a microreactor and to compare the performance to a batch reactor. The undeniable advantages of continuous microreactor systems for this process were demonstrated. Furthermore, the influence of the organic to aqueous phase ratio in the microreactor was investigated. A model of the reaction course was formulated based on experimental data. This model was used in the analysis and modeling of the alkylation process in a microreactor and found to be adequate. The optimal microreactor performance conditions were determined using the numerical optimization technique (Harrington's desirability function) and confirmed by experiments. [source] Development of an Industrial Multi-Injection Microreactor for Fast and Exothermic Reactions , Part IICHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 8 2008D. M. Roberge Abstract A Grignard reaction performed in a microreactor is presented. The reaction is of type A (highly exothermic and very rapid) and has a low yield which is attributed to a hot spot formed in the mixing zone of the reactor. The reaction yield could be significantly increased by applying the multi-injection principle, leading to better thermal control in the microreactor. Nevertheless, the microreactor plays a major role in reducing the magnitude of the hot spot. Knowing this, it was possible to design and construct an industrial microreactor with significant advantages such as modularity, high flow rate operation, and low investment expenditure (pumps and flow controller minimization). [source] Integration of a Microreactor in an Existing Production PlantCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2007D. Kirschneck Abstract The installation of a StarLam 3000 microreactor in an existing production plant is reported. The aim was to double the capacity of a running two step batch process. This was achieved by installing the microreactor for the first reaction step. A higher reaction rate made it possible to reach overall throughputs of 3.6 tons per hour. Additionally energy savings were achieved. The microreactor is running in production for more than a year now. [source] ChemInform Abstract: Copper-Mediated N- and O-Arylations with Arylboronic Acids in a Continuous Flow Microreactor: A New Avenue for Efficient Scalability.CHEMINFORM, Issue 14 2009Brajendra K. Singh Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Optimization of Glycosylation Reactions in a Microreactor.CHEMINFORM, Issue 24 2007Karolin Geyer Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] A Microreactor for Microwave-Assisted Capillary (Continuous Flow) Organic Synthesis.CHEMINFORM, Issue 42 2005Eamon Comer Abstract For Abstract see ChemInform Abstract in Full Text. [source] On-line sample preconcentration with chemical derivatization of bacterial biomarkers by capillary electrophoresis: A dual strategy for integrating sample pretreatment with chemical analysisELECTROPHORESIS, Issue 21 2005Adam S. Ptolemy Abstract Simple, selective yet sensitive methods to quantify low-abundance bacterial biomarkers derived from complex samples are required in clinical, biological, and environmental applications. In this report, a new strategy to integrate sample pretreatment with chemical analysis is investigated using on-line preconcentration with chemical derivatization by CE and UV detection. Single-step enantioselective analysis of muramic acid (MA) and diaminopimelic acid (DAP) was achieved by CE via sample enrichment by dynamic pH junction with ortho -phthalaldehyde/N -acetyl- L -cysteine labeling directly in-capillary. The optimized method resulted in up to a 100-fold enhancement in concentration sensitivity compared to conventional off-line derivatization procedures. The method was also applied toward the detection of micromolar levels of MA and DAP excreted in the extracellular medium of Escherichia coli bacterial cell cultures. On-line preconcentration with chemical derivatization by CE represents a unique approach for conducting rapid, sensitive, and high-throughput analyses of other classes of amino acid and amino sugar metabolites with reduced sample handling, where the capillary functions simultaneously as a concentrator, microreactor, and chiral selector. [source] Conducting and Superhydrophobic Rambutan-like Hollow Spheres of Polyaniline,ADVANCED MATERIALS, Issue 16 2007Y. Zhu Superhydrophobic polyaniline (PANI) hollow spheres (see figure and cover) with high conductivity were self-assembled by using perfluorooctane sulfuric acid (PFOSA) as both dopant and soft template. It is proposed that these spheres are formed by a co-operative effect of two self-assembly processes: spherical micelles composed of PFOSA serve as a "microreactor" and PFOS/aniline salt micelles act as the soft template of the PANI nanofibers. [source] A Palladium Wall Coated Microcapillary Reactor for Use in Continuous Flow Transfer HydrogenationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Christian Abstract Herein we describe the preparation of a novel continuous flow multi-channel microreactor in which the internal surface has been functionalised with a palladium coating, enabling its use in catalytic heterogeneous liquid-phase reactions. Simple chemical deposition techniques were used to immobilise palladium(0) on the channel wall surface of a polymeric multi-capillary extrudate made from ethylene-vinyl alcohol copolymer. The Pd coating of the microcapillaries has been characterised by mass spectrometry and light and electron microscopy. The functional activity of the catalytic Pd layer was tested in a series of transfer hydrogenation reactions using triethylsilane as the hydrogen source. [source] Investigation of multiphase hydrogenation in a catalyst-trap microreactorJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2009S. McGovern BACKGROUND: Multiphase hydrogenation plays a critical role in the pharmaceutical industry. A significant portion of the reaction steps in a typical fine chemical synthesis are catalytic hydrogenations, generally limited by resistances to mass and heat transport. To this end, the small-scale and large surface-to-volume ratios of microreactor technology would greatly benefit chemical processing in the pharmaceutical and other industries. A silicon microreactor has been developed to investigate mass transfer in a catalytic hydrogenation reaction. The reactor design is such that solid catalyst is suspended in the reaction channel by an arrangement of catalyst traps. The design supports the use of commercial catalyst and allows control of pressure drop across the bed by engineering the packing density. RESULTS: This paper discusses the design and operation of the reactor in the context of the liquid-phase hydrogenation of o-nitroanisole to o-anisidine. A two-phase ,flow map' is generated across a range of conditions depicting three flow regimes, termed gas-dominated, liquid-dominated, and transitional, all with distinctly different mass transfer behavior. Conversion is measured across the flow map and then reconciled against the mass transfer characteristics of the prevailing flow regime. The highest conversion is achieved in the transitional flow regime, where competition between phases induces the most favorable gas,liquid mass transfer. CONCLUSION: The results are used to associate a mass transfer coefficient with each flow regime to quantify differences in performance. This reactor architecture may be useful for catalyst evaluation through rapid screening, or in large numbers as an alternative to macro-scale production reactors. Copyright © 2008 Society of Chemical Industry [source] Analysis of a pressure-driven folding flow microreactor with nearly plug-flow characteristicsAICHE JOURNAL, Issue 8 2010A. Vikhansky Abstract We discuss the possibility of designing a pressure-driven single-phase microreactor with characteristics similar to that in an ideal plug-flow reactor. We consider equations for the moments of the residence time distribution and investigate the behavior of the solution in long spatially-periodic channels. If the microreactor consists of a large number of folding flow elements, the chaotic advection plays a double role: it mixes the chemical species and suppresses the axial dispersion. It is shown using analytical estimates and numerical modeling that chemical reactions have different sensitivity to the axial dispersion and for some reactions the effect of dispersion can be successfully eliminated. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Modeling of extraction behavior of docosahexaenoic acid ethyl ester by utilizing slug flow prepared by microreactorAICHE JOURNAL, Issue 8 2010Eiji Kamio Abstract The liquid,liquid extraction dynamics of an ethyl ester of docosahexaenoic acid (DHA-Et) with silver ion was investigated. The kinetic model was derived according to the following stepwise processes: Diffusion of DHA-Et across the organic film, complex-formation between DHA-Et and silver ion at the interface, and diffusion of extracted complex across the aqueous film. The kinetic parameters for the complex-formation reaction were determined from the investigation with the stirred transfer cell. With the proposed model and determined parameters, we predicted the uptakes of DHA-Et for the extraction system utilizing a slug flow prepared by a microchip. The calculated uptakes showed good correlation to the experimental data. The theoretical investigation suggested that the fast equilibration realized for the slug flow extraction system was due to the large specific interfacial area of the slug caused by the presence of wall film and the thin liquid film caused by the internal circulation. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Chemical-looping combustion process: Kinetics and mathematical modelingAICHE JOURNAL, Issue 4 2010Ion Iliuta Abstract Chemical Looping Combustion technology involves circulating a metal oxide between a fuel zone where methane reacts under anaerobic conditions to produce a concentrated stream of CO2 and water and an oxygen rich environment where the metal is reoxidized. Although the needs for electrical power generation drive the process to high temperatures, lower temperatures (600,800°C) are sufficient for industrial processes such as refineries. In this paper, we investigate the transient kinetics of NiO carriers in the temperature range of 600 to 900°C in both a fixed bed microreactor (WHSV = 2-4 g CH4/h/g oxygen carrier) and a fluid bed reactor (WHSV = 0.014-0.14 g CH4/h per g oxygen carrier). Complete methane conversion is achieved in the fluid bed for several minutes. In the microreactor, the methane conversion reaches a maximum after an initial induction period of less than 10 s. Both CO2 and H2O yields are highest during this induction period. As the oxygen is consumed, methane conversion drops and both CO and H2 yields increase, whereas the CO2 and H2O concentrations decrease. The kinetics parameter of the gas,solids reactions (reduction of NiO with CH4, H2, and CO) together with catalytic reactions (methane reforming, methanation, shift, and gasification) were estimated using experimental data obtained on the fixed bed microreactor. Then, the kinetic expressions were combined with a detailed hydrodynamic model to successfully simulate the comportment of the fluidized bed reactor. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Application of direct fluid flow oscillations to improve mixing in microbioreactorsAICHE JOURNAL, Issue 10 2009X. Li Abstract This article describes an active mixing method for a microbioreactor that was designed, simulated, tested, and successfully implemented. By applying a varying pressure to a microchannel looping tangentially into a cylindrical microreactor an oscillating fluid flow was shown to occur. Such an oscillating fluid flow improved mixing, both by diffusion and convection. The oscillating fluid flow has a large impact on the ratio between the diffusion domain and the convection domain. A good match was obtained between experimental mixing results, computational fluid dynamics simulation results and the results of a simplified mixing model thus demonstrating the potential of simulation on improving the design of microreactors. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Hydrodynamics and mass transfer of gas,liquid flow in a falling film microreactorAICHE JOURNAL, Issue 5 2009Haocui Zhang Abstract In this article, flow pattern of liquid film and flooding phenomena of a falling film microreactor (FFMR) were investigated using high-speed CCD camera. Three flow regimes were identified as "corner rivulet flow," "falling film flow with dry patches," and "complete falling film flow" when liquid flow rate increased gradually. Besides liquid film flow in microchannels, a flooding presented as the flow of liquid along the side wall of gas chamber in FFMR was found at high liquid flow rate. Moreover, the flooding could be initiated at lower flow rate with the reduction of the depth of the gas chamber. CO2 absorption was then investigated under the complete falling flow regime in FFMR, where the effects of liquid viscosity and surface tension on mass transfer were demonstrated. The experimental results indicate that kL is in the range of 5.83 to 13.4 × 10,5 m s,1 and an empirical correlation was proposed to predict kL in FFMR. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Methane steam reforming at microscales: Operation strategies for variable power output at millisecond contact timesAICHE JOURNAL, Issue 1 2009Georgios D. Stefanidis Abstract The potential of methane steam reforming at microscale is theoretically explored. To this end, a multifunctional catalytic plate microreactor, comprising of a propane combustion channel and a methane steam reforming channel, separated by a solid wall, is simulated with a pseudo 2-D (two-dimensional) reactor model. Newly developed lumped kinetic rate expressions for both processes, obtained from a posteriori reduction of detailed microkinetic models, are used. It is shown that the steam reforming at millisecond contact times is feasible at microscale, and in agreement with a recent experimental report. Furthermore, the attainable operating regions delimited from the materials stability limit, the breakthrough limit, and the maximum power output limit are mapped out. A simple operation strategy is presented for obtaining variable power output along the breakthrough line (a nearly iso-flow rate ratio line), while ensuring good overlap of reaction zones, and provide guidelines for reactor sizing. Finally, it is shown that the choice of the wall material depends on the targeted operating regime. Low-conductivity materials increase the methane conversion and power output at the expense of higher wall temperatures and steeper temperature gradients along the wall. For operation close to the breakthrough limit, intermediate conductivity materials, such as stainless steel, offer a good compromise between methane conversion and wall temperature. Even without recuperative heat exchange, the thermal efficiency of the multifunctional device and the reformer approaches ,65% and ,85%, respectively. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Hydrogen generation in a reverse-flow microreactor: 1.AICHE JOURNAL, Issue 8 2005Model formulation, scaling Abstract A 1-D model for methane partial oxidation in a tubular microreactor is considered. This work is motivated by a recent report by Kikas et al. that experimentally demonstrated the possibility of autothermal generation of hydrogen by partial oxidation of methane in a tubular microreactor. The reactor consists of four cylindrical channels, each 500 microns in diameter, containing Pt/13%,Rh catalyst. Autothermal generation of hydrogen was possible in both unidirectional (UD) and reverse-flow (RF) operations of the reactor, with the RF operation providing better hydrogen yield and lower temperatures than those of the UD operation. Critical comparison of methane oxidation and reforming kinetics from the literature is performed. An analysis of the timescales of individual processes within the reactor is presented to gain fundamental insight into the reactor operation. Finally, the effect of radiation heat transfer is also considered, and it is found to play an important role for a shorter-size reactor. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] Kinetics of cellulose conversion at 25 MPa in sub- and supercritical waterAICHE JOURNAL, Issue 1 2004Mitsuru Sasaki Abstract Experiments of microcrystalline cellulose conversion in subcritical and supercritical water were conducted at temperatures between 290 and 400°C, a pressure of 25 MPa, and residence times of 0.02,13.1 s using a continuous-flow-type microreactor. First, the reaction mechanism of microcrystalline cellulose in subcritical and supercritical water was proposed on the basis of detailed product analyses. Next, the kinetic description of this reaction in subcritical and supercritical water using a grain model was carried out to verify the proposed reaction mechanism and consequently found that the reaction-rate models were able to express the reaction of microcrystalline cellulose at identical conditions. © 2004 American Institute of Chemical Engineers AIChE J, 50: 192,202, 2004 [source] Encapsulation of a Single Metal Nanoparticle with Tunable Size in a Monodisperse Polymer MicrocapsuleMACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2009Haiqing Li Abstract A versatile approach to fabricate monodisperse poly[styrene- co -(divinyl benzene)] (PS- co -DVB) microcapsules that contain a single gold nanoparticle (AuNP) has been demonstrated. Using the PS- co -DVB microcapsule as a microreactor, aqueous HAuCl4 and NaBH4 solutions are subsequently infiltrated. The size of the resulting AuNP inside of the PS- co -DVB microcapsules is easily tunable by controlling the repeated infiltration cycles of aqueous HAuCl4 and NaBH4. PS- co -DVB microcapsules that contain a single silver and palladium nanoparticle are also obtained by following a similar protocol. [source] Heat Transfer in Gas Phase Olefin PolymerisationMACROMOLECULAR SYMPOSIA, Issue 1 2009Estevan Tioni Abstract A fixed bed microreactor has been used to study heat transfer during the initial transient state of gas phase olefin polymerization on a supported catalyst. It has been shown that heat transfer during this stage of the polymerisation is critical, and under conditions found commercially problems can arise with hot spots and polymer melting. It is proven how the thermal properties of the gas mixture flowing on the catalytic bed exert great influence on heat dissipation reducing the sudden increase in temperature by as much as a factor of 5. Flow rate and especially the process gas composition are the key factors in controlling the bed temperature. [source] Microreactor Array Assembly, Designed for Diversity Oriented Synthesis Using a Multiple Core Structure Library on Solid SupportMOLECULAR INFORMATICS, Issue 11 2006Alexander Groß Abstract The application of spatially encoded principles in solid phase combinatorial synthesis requires no chemical or physical coding strategies. The resulting products are encoded by their position inside the array and their synthesis history. The advantages of microreactor arrays for solid phase synthesis as one of the embodiments in the field of microreaction technology are discussed. Here, we review the reactor design, necessary process steps, and a strategy for the diversity oriented array synthesis. In particular, the glass-made microreactor and its assembly for 1563 parallel solid phase reactions, which can be performed at temperatures up to 120,°C, are described. Bead loading and liquid handling steps were adapted to this array. The production of large libraries demands suitable synthesis protocols and building blocks. The optimization of appropriate synthesis conditions is a time-consuming process. A multiple core structure library approach for the efficient synthesis of diverse heterocyclic libraries is described. The aim of this work was to prove the feasibility of the glass-microreaction array for massive parallel library synthesis. [source] Active microfiltered sensor interfaces, photocatalytic reactors, and microbatteries using combined micro/nanoporous interfacesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2009James L. Gole Abstract Select active micro/nanoporous porous silicon (PS) interfaces have been formed and treated to form the scaffolding for sensors, photocatalysis-based microreactors, and PS-based lithium ion batteries. The introduction of active nanostructures is used to form sensitive and selective sensors. The introduction of TiO2-xNx visible light absorbing nanophotocatalysts to the PS structure for the purpose of creating a microreactor, the concomitant metal ion seeding of these nanostructures to promote infrared spectral enhancement, introduce rapid room temperature phase transformation, and provide the potential for a novel active photovoltaic response are outlined. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Efficient on-chip proteolysis system based on functionalized magnetic silica microspheresPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2007Yan Li Abstract An easily replaceable enzymatic microreactor has been fabricated based on the glass microchip with trypsin-immobilized magnetic silica microspheres (MS microspheres). Magnetic microspheres with small size (,300,nm in diameter) and high magnetic responsivity to magnetic field (68.2,emu/g) were synthesized and modified with tetraethyl orthosilicate (TEOS). Aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA) were then introduced to functionalize the MS microspheres for enzyme immobilization. Trypsin was stably immobilized onto the MS microspheres through the reaction of primary amines of the proteins with aldehyde groups on the MS microspheres. The trypsin-immobilized MS microspheres were then locally packed into the microchannel by the application of a strong field magnet to form an on-chip enzymatic microreactor. The digestion efficiency and reproducibility of the microreactor were demonstrated by using cytochrome c (Cyt-C) as a model protein. When compared with an incubation time of 12,h by free trypsin in the conventional digestion approach, proteins can be digested by the on-chip microreactor in several minutes. This microreactor was also successfully applied to the analysis of an RPLC fraction of the rat liver extract. This opens a route for its further application in top-down proteomic analysis. [source] Nanosecond pulsed electric field generators for the study of subcellular effectsBIOELECTROMAGNETICS, Issue 3 2006Juergen F. Kolb Abstract Modeling and experimental studies have shown that pulsed electric fields of nanosecond duration and megavolt per meter amplitude affect subcellular structures but do not lead to the formation of large pores in the outer membrane. This "intracellular electromanipulation" requires the use of pulse generators which provide extremely high power but low energy pulses. In this study, we describe the concept of the required pulsed power sources, their design, operation, and the necessary diagnostics. Two types of pulse generators based on the Blumlein line principle have been developed and are described here. One system is designed to treat a large number of cells in cuvettes holding volumes from 0.1 to 0.8 ml. Pulses of up to 40 kV amplitude, with a duration of 10 ns and a rise time close to 1 ns can be applied to the cuvette. For an electrode gap of 1 mm this voltage corresponds to an average electric field of 40 MV/m. The second system allows for real time observation of individual cells under a microscope. It generates pulses of 10,300 ns duration with a rise time of 3.5 ns and voltage amplitudes up to 1 kV. Connected to a microreactor with an electrode gap of 100 µm, electric fields up to 10 MV/m are applied. Bioelectromagnetics 27:172,187, 2006. © 2005 Wiley-Liss, Inc. [source] Design and characterization of a prototype enzyme microreactor: Quantification of immobilized transketolase kineticsBIOTECHNOLOGY PROGRESS, Issue 1 2010S. Matosevic Abstract In this work, we describe the design of an immobilized enzyme microreactor (IEMR) for use in transketolase (TK) bioconversion process characterization. The prototype microreactor is based on a 200-,m ID fused silica capillary for quantitative kinetic analysis. The concept is based on the reversible immobilization of His6 -tagged enzymes via Ni-NTA linkage to surface derivatized silica. For the initial microreactor design, the mode of operation is a stop-flow analysis which promotes higher degrees of conversion. Kinetics for the immobilized TK-catalysed synthesis of L -erythrulose from substrates glycolaldehyde (GA) and hydroxypyruvate (HPA) were evaluated based on a Michaelis,Menten model. Results show that the TK kinetic parameters in the IEMR (Vmax(app) = 0.1 ± 0.02 mmol min,1, Km(app) = 26 ± 4 mM) are comparable with those measured in free solution. Furthermore, the kcat for the microreactor of 4.1 × 105 s,1 was close to the value for the bioconversion in free solution. This is attributed to the controlled orientation and monolayer surface coverage of the His6 -immobilized TK. Furthermore, we show quantitative elution of the immobilized TK and the regeneration and reuse of the derivatized capillary over five cycles. The ability to quantify kinetic parameters of engineered enzymes at this scale has benefits for the rapid and parallel evaluation of evolved enzyme libraries for synthetic biology applications and for the generation of kinetic models to aid bioconversion process design and bioreactor selection as a more efficient alternative to previously established microwell-based systems for TK bioprocess characterization. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Ni Catalyst Coating on Fecralloy® Microchanneled Foils and Testing for Methane Steam ReformingCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010N. de Miguel Abstract The procedure following the washcoating of three different Ni catalyst systems (MgO, Al2O3, and CeO2/Al2O3 supported) on pretreated Fecralloy® microchanneled foils under controlled milling times and viscosities of the slurries is described. The activity of the prepared coatings is also presented. Four different series of coated foils were prepared: one per each catalyst system, keeping constant the average particle size on 5 ,m, and one extra series to study the effect of reducing the average particle size of the MgO-supported catalyst system to 3 ,m. For each coating, scanning electron microscopy pictures were taken and specific surface areas and average densities of the catalyst layers were estimated. Finally, each series of coated foils was stacked and tested in a microreactor for the methane steam reforming (MSR) reaction under different conditions. [source] Guidance on Safety/Health for Process Intensification including MS Design; Part I: Reaction HazardsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2009O. Klais Abstract The implementation of process intensification by multiscale equipment will have a profound impact on the way chemicals are produced. The shift to higher space-time yields, higher temperatures, and a confined reaction volume comprises new risks, such as runaway reactions, decomposition, and incomplete conversion of reactants. Simplified spreadsheet calculations enable an estimation of the expected temperature profiles, conversion rates, and consequences of potential malfunction based on the reaction kinetics. The analysis illustrates that the range of optimal reaction conditions is almost congruent with the danger of an uncontrolled reaction. The risk of a spontaneous reaction with hot spots can be presumed if strong exothermic reactions are carried out in micro-designed reactors. At worst, decomposition follows the runaway reaction with the release of noncondensable gases. Calculations prove that a microreactor is not at risk in terms of overpressure as long as at least one end of the reactor is not blocked. [source] Experimental Investigation and Modeling Approach of the Phenylacetonitrile Alkylation Process in a MicroreactorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2009E. S. Borovinskaya Abstract The application of microreaction technology has the potential to intensify chemical processes. It is therefore of great interest to investigate the operating efficiency of a multiphase process such as the alkylation of phenylacetonitrile in a microreactor and to compare the performance to a batch reactor. The undeniable advantages of continuous microreactor systems for this process were demonstrated. Furthermore, the influence of the organic to aqueous phase ratio in the microreactor was investigated. A model of the reaction course was formulated based on experimental data. This model was used in the analysis and modeling of the alkylation process in a microreactor and found to be adequate. The optimal microreactor performance conditions were determined using the numerical optimization technique (Harrington's desirability function) and confirmed by experiments. [source] Development of an Industrial Multi-Injection Microreactor for Fast and Exothermic Reactions , Part IICHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 8 2008D. M. Roberge Abstract A Grignard reaction performed in a microreactor is presented. The reaction is of type A (highly exothermic and very rapid) and has a low yield which is attributed to a hot spot formed in the mixing zone of the reactor. The reaction yield could be significantly increased by applying the multi-injection principle, leading to better thermal control in the microreactor. Nevertheless, the microreactor plays a major role in reducing the magnitude of the hot spot. Knowing this, it was possible to design and construct an industrial microreactor with significant advantages such as modularity, high flow rate operation, and low investment expenditure (pumps and flow controller minimization). [source] | |||||||||||||||||||||||||||||||