How to select the Reactor

The MicroFLO^TM reactor geometry has been designed to be “Space-filling” i.e., the reactor affords a greater proportion of footprint to the process fluid than other common plate reactor designs. This along with its high heat transfer performance makes it exceptionally well suited for photo-catalysis. The process is sandwiched between the utility plate and a UV transparent glass sheet which is illuminated by appropriately chosen LEDs. The depth of the process channel can be engineered to maximize photon efficiency. The metal can be lined with tantalum for exceptional corrosion resistance.

For reactions like nitrations without mixed acids, peroxide driven oxidations, and some of the slower Grignard syntheses, the high surface area of the MicroFLO^TM is often not necessary. In such cases, the Amar series of tubular reactors should be preferred. Where heat transfer is important but a broader residence time distribution is tolerable, we suggest our patented PinchFLO^TM reactors whose unique extended surfaces and novel “pinched” structure offer several times the heat transfer performance compared to straight tubes. However, the residence time distribution is not conducive to selectivity. If the selectivity is important, we suggest our patented CorFLO^TM reactors with comparable heat transfer performance but very narrow residence time distributions. The CorFLO^TM reactors have removable Kenics type static mixers as inserts which make them especially applicable for fouling services. However, none of these reactors can handle slurries heavier than about 2%. For these applications, we provide the SlurryFLO^TM and VishwaFLO^TMreactors.

For reactions that have long residence times (greater than 30 mins), but which involve multiphase contacting, passive devices like the MicroFLO^TM, PinchFLO^TM or CorFLO^TM give poor performance. The latter also perform poorly when there are more than 2% by weight of solids in the process. We provide the SlurryFLO^TM reactor and VishwaFLO^TMreactors for such applications. The SlurryFLO^TM reactor is composed of a number of cells, each agitated by two impellers mounted on a horizontal shaft that runs through all cells. Each cell is seperated is from its neighbors by an overflow partition. Process fluid including light slurries (less than 20% by weight of solids) overflows from one cell into the next. Each cell behaves like two stirred tank reactors in series. The SlurryFLO^TM can also be used for anti-solvent crystallization.

The VishwaFLO^TM reactor is a single horizontal vessel which is provided with patented von Karman impellers mounted on a horizontal shaft that runs the length of the vessel. Each impeller is a single long baffle mounted about mid-way between the shaft and the shell of the reactor and occupies about 1/3rd of the radial gap. Up to four impellers are provided per reactor. The von Karman impellers ensure a high degree of plug flow even without physical partitions. Due to its open structure, the VishwaFLO^TMreactor can handle heavy settling slurries (>20% w/w), without choking. Additionally, it can be fitted with a helical ribbon impeller to allow for surface scraping and maintenance of heat transfer surfaces. In fact, this reactor can work for any shear thinning fluid. The reactor can further be employed for cooling or evaporative crystallization and can also function as liquid-liquid extractor.

Both these reactors can be employed for multi-phase reactions such as substituted toluene oxidations, heterogeneously catalyzed reactions such as hydrogenations using Raney nickel or palladium on carbon, and esterification with continuous removal of water. It is also possible to envisage these reactors for suspension and emulsion polymerizations.