Scale static mixers

Often, small scale static mixers do not fit correctly into a circular pipe. Consideration mnst be made as to how significant this is for the mixing process being investigated. 

The mixing sensitivity of (fast) polymerizations is known and frequently described in literature. This is due to the fact that radical polymerizations typically take 1 s until chain termination [125]. However, typical mixing times of large-scale mixers, including conventional static mixers, are longer. Accordingly, the course of mixing has an effect on the product quality, i.e. the polymer-chain distribution. 

Figure 4.75 Radical polymerization of acrylates in a laboratory-scale experimental set-up with a micro mixer as premixer. Less fouling at the feeding point of the static mixer (compare with Figure 4.74) (top) and molecular weight distribution (bottom) [125. ...

Construction of a plexiglass scale model for cold flow studies typically occurs after completion of the CFD analysis. Smoke entrained in an air stream is used to empirically confirm the SCR design. Tuning efficiencies of the guide vanes and mixing ability of the static mixers are some of the design qualities confirmed by the cold low model. Figure 17.15 is a picture of an actual model used for commercial scale-up. 

The conversion of 2 to 3 was optimized at full scale in the VRT reactor. In addition to confirming the productivity, safety, product quality, and economic benefit of the process, the robustness of the process was also demonstrated. Finally, this pilot study provided the basis for a full-scale commercial manufacturing design specification. Having fixed the optimum residence time, the process was then transferred into a plant Fixed Residence Time (FRT) cyanation reactor which employed a fixed length of jacketed static mixer for commercial manufacture. This FRT was capable of producing 300 metric tonnes per year of 3, with the same purified step yield of 80% that was achieved in the laboratory capillary reactor. 

OD) tubing in Figure 11.4 and on a pilot plant scale with a series of static mixers followed by a 0.41-inch ID residence time section in Figure 11.5. The telescoped conhnuous process gives yields and quality comparable with those of the batch process for celecoxib. 

Scaled exergy input of the alternative extruder and regular extruder plotted against static mixer diameter. 

The change from extruder to gear pump/static mixer could potentially increase the gel count. As LDPE and LLDPE primarily find their uses in foils, laboratory scale tests are recommended to assess the impact of the proposed setup on the gel count. Extruders usually decrease the gel count by kneading the polymer. It is unclear whether the proposed setup can accomplish the same. 

Many passive microstructured mixers (see e.g. [2, 3]) follow design principles used at the macro-scale for static mixers with internal packings [4], It stands to reason that some of the advantages in processing claimed for conventional static mixer also apply or may be even more pronounced when using static mixers [4] ... 

Figure 1.4 Micro mixers (laboratory scale) and micro structured mixers (pilot scale) close the gap with static mixers, yielding apparatus for a multi-scale concept. Today s microstructured devices achieve mixing at up to about 1 m3 fT1 liquid throughput [2, 64] (by courtesy of RSC and Chemical Engineering).

Bertsch, A., Heimgartner, S., Cousseau, P., Renaud, P., Static micromixers based on large-scale industrial mixer geometry, Lab Chip 2001, 1, 56-60. 

Zhou OS. Ozone disinfection of sewage in a static mixer contacting reactor system on a plan scale. Ozone Sci Eng 1991 13 313-330. 

Methodologies for scale-out to phase II—III clinical trials are also given in Figure 5.12 [44]. One approach would be to scale up the c-SSP using static mixers and mini-heat exchangers, which are already in operation at Lonza. The possible... 

Scale- Up Agitated Vessels with Recycle Loops with Semi-Batch Feed to an In-Line Mixer in the Recycle Loop. Knight (1995) and Colleagues (1995) conducted a rather definitive study that determined the pertinent scale-up parameters for a static mixer in a recycle loop. They used a 20 liter semi-batch reactor agitated with... 

Figure 10.48 presents data of yield (as a fraction of the DMP hydrolyzed) of the slow hydrolysis reaction versus residence time in the mixer. The correlation is not perfect however, the results of this study indicate that, to be conservative, one must scale-up using equal residence time in static mixer. 

Note that HP/V in the laboratory reactor was only 2.5 HP/1000 gal whereas in the plant reactor it is 141 HP/ lOOOga/. This scale-up is right on the verge of not being practical. For any larger plant reactor one would need to use a recycle loop with a static mixer to do a practical scale-up. 

Scale-up of a Static Mixer Reactor for the Fourth Bourne Reaction... 

Recommendations for Handling Blending Requirements for Fast Reactions. For handling fast reactions, if the power requirements are unreasonable to maintain equal blend time on scale-up, then one should consider two alternates (1) inject the semi-batch feed into a recycle loop in the inlet of a static mixer and (2) do the reaction in-line while pumping out the vessel through an in-line mixer. 

Kataoka T and Nishiki T. Dispersed mean drop sizes of (W/0)/W emulsions in a stirred tank. J Chem Eng Jpn 1986 19 408-412. Nishikawa M, Mori F, and Fujieda S. Average drop size in a liquid-liquid phase mixing vessel. J Chem Eng Jpn 1987 20 82-88. Nishikawa M, Mori F, Fujieda S, and Kayama T. Scale-up of liquid-liquid phase mixing vessel. J Chem Eng Jpn 1987 20 454—459. Berkman PD and Calabrese RV. Dispersion of viscous liquids by turbulent flow in a static mixer. AIChE J 1988 34 602-609. Chatzi EG, Gavrielides AD, and Kiparissides C. Generalized model for prediction of the steady-state drop size distributions in batch stirred vessels. Ind Eng Chem Res 1989 28 1704—1711. 

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