Simulation of Micromixing in a Turbulent Tubular Reactor With Concentric Feed

Bourne, J.R.; Maire, Horst

doi:10.1080/00986449208935995

Cited by 3 publications

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“…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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