StarLam mixer

This approaches the performance of conventional static mixers, closing the gap between this smallest class of industrially used apparatus and micro mixers for analytical purposes [130], Thus, a toolbox of microstructured mixers is available for the whole range of flow rates. This box comprises interdigital multi-laminating with a few ml h 1 capacity and split-and-recombine micro mixers (caterpillar type) up to 1001 h 1 as well as interdigital concentric microstructured mixers (StarLam type) series achieving 300, 1000 and up to 3000 1 h, dependent on the respective sub-version. 

Figure 1.111 Flow rate dependence of the Dushman mixing quality of the interdigital concentric consecutive microstructured mixers of the StarLam series and other micro mixers taken for benchmarking [130].

Figure 5.32 StarLam 3000 microstructured mixer retrofitted to existing plant peripherals and tank reactor (by courtesy of Wiley-VCH Verlag GmbH) [67],...

The inlet pipes of the two starting reactants to the batch vessel were simply connected to the StarLam mixer [67]. The only difference to the previous feed lines was the installation of filter cartridges before the entries to the microstructured mixer, necessary to avoid blocking of the reactor. The pressure drop in the lines was lower than 3 bar so that it was possible to keep the pumps used before in the plant. At the outlet of the reactor, a tube reactor was installed. During optimization it was found that it is sufficient to insulate this tube to reach the temperature needed to finish the reaction. The pipe ended directly in the batch vessel where the second endothermic reaction step was carried out as before. 

The first start-up of the plant was in June 2005 [67]. A temperature diagram shows that most of the heat is released in the retention time tube (see Figure 5.33). The temperature measured directly at the outlet of the microstructured mixer-reactor StarLam 3000 was below 50 °C even at higher throughputs. During the retention time, tube temperatures up to about 130 °C were reached. The throughputs for this first test mn were increased in three steps to up to 3600 kg/h. 

StarLam microstructured mixers consist of disk-like platelets with a hollow starshaped feeding zone where the fluid is re-directed into an inner central circular mixing zone (Fig. 6.6) [21] (see also Refs. [1, 9]). Many such platelets form a complete, rod-shaped inner mixing channel into which the several streams are injected, virtually via small slit-like nozzles. For efficient mixing, injection in the turbulent range is advised. The flow properties at small Re are less well known. 

This concept has attracted increasing attention from industrial clients, since the StarLam mixer can easily be cleaned, enables large throughputs (up to 1000 L h ) at a compact size of no larger than a fist, and can be simply attached in existing plants via industrially used flange connectors (see Fig. 6.6) (alternatively, the common Swagelok connectors may be used) [21]. 

StarLam mixers use the internal numbering-up ( equaling-up ) concept for throughput enhancement, by simply adding more platelets into the stack (Fig. 6.7)... 

Fig. 6.6 Generic assembly of StarLam mixers. A two-set series of platelets with star-shaped and circular breakthroughs is stacked and oriented by two guiding pins in a recess of a three-piece housing. By screwing, the platelets are pressed into contact. Industrial flange connectors make insertion of these devices...

Fig. 6.7 Equaling-up for the StarLam mixer series by varying the number of microstructured platelets [27. To have the same volume filled within the recess of the housing, a dummy block with inner channel is placed on top of the platelet stack for...

Fig. 6.17 A mixing test station for pilot-sized microstructured mixers up to the 5000-l/h range. Shown above are three StarLam microstructured mixers.

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