Reactor mixer-settler

Liquid-liquid reactors Column reactor Mixer-settler reactor... 

Fig. 26. Mechanically agitated industrial contactors, (a) mixer-settler (b) rotating-disk column (c) mixco column (d) asymmetric rotating-disk column (e) pulsed packed column (f) Podbielniak centrifugal extractor. (Reprinted from Doraiswamy, L. K and Sharma, M. M., Heterogeneous Reactions Analysis, Examples and Reactor Design, Vols. I and 2, 1984, John Wiley and Sons.)...

An extreme case of the mixer-settler is the pump reactor, wherein the reaction occurs within the pump itself. The pump provides mixing and short contact time. These reactors are useful for fast reactions requiring high mixing and short time, as in some aromatic nitration reactions. As indicated later, pump reactors are also useful for some polymeric reactions. 

Solvent extraction can be carried out in pulsated extraction columns, in mixer-settlers or in centrifuge extractors. Organic compounds such as esters of phosphoric acid, ketones, ethers or long-chain amines are applied as extractants for U and Pu. Some extraction procedures are listed in Table 11.11. The Purex process has found wide application because it may be applied for various kinds of fuel, including that from fast breeder reactors. The Thorex process is a modification of the Purex process and has been developed for reprocessing of fuel from thermal breeders. 

Most PTC reactions are carried out on an industrial scale in the batch mode in mixer-settler arrangements. In view of the reactor design in the liquid-solid-liquid PT-catalyzed reaction, Ragaini and coworkers [147-149] reported the use of fixed-bed reactors with a recycling pump or with a recycling pump and an ultrasonic mixer, and emphasized the importance of effluent recycle concept. Schlunt and Chau [150] reported the use of a cyclic slurry reactor, which allowed the immiscible reactants to contact the catalyst sites in controlled sequential steps. However, for triphase reactions in liquid-liquid systems where... 

Desktop Chemical Factory, Fig. 5 United microreactor system. Example of a modular backbone 1 heat exchanger, 2 mixer, 3 valve, 4 safety valve, 5 pump, 6 heated residence time module, 7 mixer-settler extractor, 8 heated mixer tube reactor, 9 thermal decoupler [12]... 

Another application of solvent extraction to redox speciation studies is the method developed for iodine (Malmbeck and Skamemark 1995). It was used for online speciation of iodine in the Forsmark BWR power plant in Sweden. Iodine can enter the reactor water in two ways, either by fission of tramp uranium (uranium that is adsorbed on the outer surface of the fuel pins) or via leaking fuel pins. In this method, a tiny stream of water was withdrawn fi-om the reactor system and used as feed for a 20 stage mixer-settler battery. The mixer-settlers were arranged in four batteries with 4, 4, 6, and 6 mixer-settler units. Part of such a mixer-settler battery is shown in O Fig. 52.4. 

Figure 11.8 Sketches of some common liquid-liquid contactor reactor designs. HP, heavy phase LP, light phase, (a) Mixer-settler, (b) horizontal pipeline mixer (static mixer), and (c) air agitated contactor.

Often homogeneous or homogeneously catalyzed reactions but even heterogeneous catalytic reactions exist batch, tank, and tube reactors, three-phase reactors, bubble columns Columns and mixer-settler... 

In the oxidation of cyclohexane, the efficiency is relatively low, which is the reason why research into and optimization of this process step was taken in hand. The flowsheet of the oxidation section is shown in fig. 1. Fresh cyclohexane is mixed with the recycled cyclohexane from the top of the cyclohexane distillation column. The mixture is fed to the condensation section to exchange heat with the vapour stream from the reactors. Next, the cyclohexane is oxidized with air in a cascade of stirred reactors. The oxidate leaving the reactors undergoes an after-treatment in a decomposition reactor, while the acids formed as byproduct in the oxidation section are neutralized in a mixer-settler unit. In the cyclohexane distillation section non-converted cyclohexane is separated from cyclohexanol, cyclohexanone and byproducts. 

R 18] A modular set of devices was developed within the pChemTec project introduced above. It consists of a base plate which is identical for all four devices. This base plate acts as the fluidic interface to the piping and is equipped with a micro structured mixer. The base plate can be combined with a heated tube to deliver a mixer-tube reactor. A combination with a porous tube delivers a degasser unit. A combination with a membrane unit (not shown) or a settler results in an extraction device (Figure 4.58). 

The process layout consists of two consecutive static mixers (Fig. 28). To the first mixer, the olefin feedstock is cofed with a recycled isobutane/alkylate stream. The stream coming out the first static mixer is then combined with the recycled IL-based composite catalyst and fed into the second static mixer where the alkylation reaction takes place at a reaction temperature around 15°C and a total pressure of 0.4 MPa. The reaction products are then sent to a settler where the composite catalyst is collected from the bottom, due to its higher density, and recycled. The supernatant is later split into a recycle (isobutane -I- alkylate) to the first static mixer upstream and a product effluent, which constitutes the incoming to the fractionation unit downstream. Total reaction time, considering residence times in the second static mixer and in the settler, is 10 min while the overall I/O ratio in the reactor is set to a value as high as 500. No details on catalyst regeneration or replacement have been disclosed (257). 

Aldehyde linearity is high (ca. 90%). Sufficient N-methyl-pyrrolidone (NMP ca. 40%w) and some water (1 -2%w) are applied to achieve a one-phase system in the reactors. After reaction, water is added in a mixer (phase ratio 1 1 v/v), followed by efficient phase separation in a settler, with virtually all catalyst in the NMP/water layer. The crude product layer is subjected to a multi-stage water extraction to remove residual NMP and catalyst, and a final treatment over a silica-bed to reduce Rh leach levels from 0.2 ppmw to 0.02 ppmw. The recycle catalyst layer (in NMP/water) is dried in two steps, to evaporate water and achieve the low water concentrations required for one-phase reaction, and then recycled to the reactors. Water is recycled, from evaporators, via water extraction, to the mixer. The flexibility of this process with respect to alkene carbon number seems excellent good performance has been found for Cs-C aUcenes [61]. 

Figure 2.11 Schematic representation of fluid-fluid microstructured reactors (a micromixer settler b cyclone mixer c interdigital mixer d microchannel with partial overlap e microchannel with membrane or metal contactor f microchannels...

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