Micromixing and fast chemical reactions in static mixers

Bourne, J.R.; Maire, Horst

doi:10.1016/0255-2701(91)80005-a

Cited by 23 publications

(17 citation statements)

References 7 publications

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“…The NETmix V R static mixer mixing efficiency was assessed through tracer flow visualization experiments in the range of Reynolds numbers 25 Re 700. The importance of the work presented lies in the fact that it contributes to the knowledge of the influence of the operating Re in the NETmix V R static mixer dynamic behavior.…”

Section: Discussionmentioning

confidence: 99%

“…Experiments were carried out in the range of Reynolds numbers 0.4 \ Re \ 300 by varying the fluid viscosity and the flow rate. Bourne and Maire 25 determined the mixing intensity of three static mixers, differing mainly in the width of their channels, by applying the engulfment model 26,27 to the measured product distribution of fast consecutive competitive azo coupling between 1-naphthol and diazotized sulfanilic acid. Bourne et al 23 and Baldyga et al 28 further extended the previous study and applied azo couplings between 1-naphthol and 2-naphthol with diazotized sulfanilic acid to the SMX …”

Section: Introductionmentioning

confidence: 99%

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NETmix®, a new type of static mixer: Experimental characterization and model validation

et al. 2011

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in Wiley Online Library (wileyonlinelibrary.com).In a previous article (Laranjeira et al.), a network model was developed to describe and predict the behavior and performance of NETmix V R , a new type of static mixer consisting of a network of interconnected chambers and channels. This work reports experimental results on a transparent prototype NETmix V R unit constructed to enable the characterization of the mixing mechanisms at the local scale. Tracer flow visualization experiments show that the mixing characteristics in the NETmix V R unit depend on the Reynolds number both for macromixing and micromixing. A critical Reynolds number for the onset of mixing was obtained where oscillating flow in the chambers is observed. Chemical reaction experiments were done using test reactions systems that exhibit mixing effects in the final product distribution and selectivity. Reaction selectivity was shown to depend on the reactants injection scheme. Theoretical predictions obtained with the network model were in agreement with experimental data for high Reynolds numbers.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

NETmix®, a new type of static mixer: Experimental characterization and model validation

et al. 2011

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“…When the viscosity increases slightly above that of water, the flow remains fully turbulent and the engulfment rate decreases according to equation (5.7) [41,45,48,51,56]. At still higher viscosity levels, the flow regime becomes transitional or laminar: here theory of reactive mixing and experimental methods [60] are still developing.…”

Section: Extensionsmentioning

confidence: 95%

“…Some mixers, whose suitability for obtaining high selectivities from fast reactions has been studied, include the centrifugal pump [33], pipeline [34][35][36], rotor-stator mixers of various sizes [37,38], thin liquid sheets [39,40], static mixers [41,42], 'T' junctions [43], free jets [44][45][46], grid turbulence [47], and agitated tanks 23,26,27,29,, as well as a tubular membrane model [S7] and a simple injector in a tube [S8]. In all these cases the energy dissipation rate, c, and hence the mixing rate and other finescale turbulence properties vary significantly from place to place.…”

Section: Characterization Of Mixersmentioning

confidence: 99%

Mixing and the selectivity of fast chemical reactions

Bourne¹

1997

Handbook of Batch Process Design

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The problemAmong the problems that arise in the scale-up of batch reactions is that of reactions whose outcome is sensitive to mixing. While many reactions do not exhibit such sensitivity, those that do can exhibit substantial yield loss on scale-up.It is the main purpose of this chapter to describe recent advances in understanding the interactions between the physical operation of mixing reagents and the distribution of products from fast reactions. Whereas much is known about the chemical factors influencing the yield of a particular product, the role of mixing is often less clear. This yield should be high when k[ » k2 and when the stoichiometric ratio (number of moles of B charged to the reaction vessel per mole of A) is around unity. (If this ratio equals or exceeds two, R will be fully converted to S as the reactions run to completion.) Experiments on the single-phase nitration of durene (l,2,4,5-tetramethylbenzene) contradicted these chemically based predictions. Although k[ is orders of magnitude greater than k 2 , measured yields of mononitrodurene (R) were much smaller than those of dinitrodurene (S) [1,2]. The yields of Rand S were increased and decreased, respectively, by increasing the intensity of agitation in the reaction vessel and by measures which retarded the reactions. Increases in the yield of the intermediate (R) as the agitation intensity was raised were also observed in the iodination of I-tyrosine [3], the bromination of 1,3,5-trimethoxybenzene [4] and in some diazo couplings to be discussed in detail later. Some competitive-consecutive reactions are characterized by k[ = 2k2 and the maximum yield of R will be 50% when the stoichiometric ratio of B to P. N. Sharratt (ed.), Handbook of Batch Process Design

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“…In the past, Li [10] and Bourne [11] have performed flow visualization experiments using acid-base indicators and reaction in millimeter (2-5 mm diameter) sized pipes to determine downstream mixing distances. To further correlate some of the mixing trends in our silicon mixers, extensive flow visualization experiments were conducted using mixing of dyes and the color change of an acid-base indicator, bromothymol blue.…”

Section: Flow Visualizationmentioning

confidence: 99%

Microfluidic sub-millisecond mixers for the study of chemical reaction kinetics

Desai

Bökenkamp²,

Yang³

et al.

Proceedings of International Solid State Sensors and Actuators Conference (Transducers '97)

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SUMMARYWe present here, a micromachined, high Reynolds number (2,000 -6,000), sub-millisecond liquid mixer for the study of chemical reaction kinetics. This 1cm x 1cm x 1mm bulk micromachined silicon mixer is capable of initiating and quenching (starting and stopping) chemical reactions in intervals as short as 100 µs. The centimeter sized mixer chip contains two tee mixers connected by one channel which serves as a reaction chamber. Each tee mixer consists of opposing channels where liquids meet head-on and exit into a third channel forming the base of a "T." Our mixer performance was characterized by employing two carefully chosen chemical reactions with reaction time constants of 3 ms and 9 ms along with visualization techniques using dyes and acid-base indicators.

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Micromixing and fast chemical reactions in static mixers

Cited by 23 publications

References 7 publications

NETmix®, a new type of static mixer: Experimental characterization and model validation

NETmix®, a new type of static mixer: Experimental characterization and model validation

Mixing and the selectivity of fast chemical reactions

Microfluidic sub-millisecond mixers for the study of chemical reaction kinetics

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