Time-Dependent Turbulent Mixing and Chemical Reaction in Stirred Tanks

TIME-DEPENDENT TURBULENT MIXING AND CHEMICAL REACTION IN STIRRED TANKS  

Blend time and ehemieal produet distribution in turbulent agitated vessels ean be predieted with the aid of Computational Fluid Mixing 

Zero equation model—mixing length model. 

Blending of ehemieal reaetants is a eommon operation in tlie ehemieal proeess industries. Blend time predietions are usually based on empuieal eorrelations. When a eompetitive side reaetion is present, the final produet distribution is often unknown until the reaetor is built. The effeets of the position of the feed stream on the reaetion byproduets are usually unknown. Also, the seale-up of ehemieal reaetors is not straightforward. Thus, there is a need for eomprehensive, physieal models that ean be used to prediet important information like blend time and reaetion produet distribution, espeeially as they relate to seale and feed position. 

The objeetive of the following model is to investigate the extent to whieh Computational Fluid Mixing (CFM) models ean be used as a tool in the design of industrial reaetors. The eommereially available program. Fluent , is used to ealeulate the flow pattern and the transport and reaetion of ehemieal speeies in stirred tanks. The blend time predietions are eompared with a literature eonelation for blend time. The produet distribution for a pair of eompeting ehemieal reaetions is eompared with experimental data from the literature. 

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Bakker, A., and Fasano, I. B., Time-Dependent, Turbulent Mixing and Chemical Reaction in Stirred Tanks, AIChE Symposium. Series No 299 90 71-78 (1993). 

Bakker A., and 1. B. Fasano (1993b). Time dependent, turbulent mixing and chemical reaction in stirred tanks, presented at the annual AIChE meeting, St. Louis, MO, Nov. AIChE Symp. Ser. 299, 90, 71-78. 

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