A new pair of reactions to characterize imperfect macro-mixing and partial segregation in a stirred semi-batch reactor
✍ Scribed by A.W. Nienow; S.M. Drain; A.P. Boyes; R. Mann; A.M. El-Hamouz; K.J. Carpenter
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 754 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0009-2509
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✦ Synopsis
A new pair of reactions has been developed based on a first order decay (an internal clock) and a parallel second order diazotisation coupling reaction, represented by A --4 S and A+B ---a R. By adjustment of concentrations and pH, the pair of rate constants can be'tuned' to various reaction speeds giving scope for assessing various rates of mixing and agitation . When B is added semi-batchwise to A, any region rich in A favours the decomposition reaction . Imperfect macro-mixing therefore leads to an increase in the less desirable by-product S . Experiments have been performed using different rates of stirring and different addition points (liquid surface or impeller) . The pair of reactions show sensitive yield variations under these different mixing conditions . Quantitative interpretation of the experiments has been based on a "networks-of-backmixed zones" model, using networks of size (20x20)+(20x40) comprising some 1200 zones . Individual species concentrations in space are presented as sectional image reconstructions . The model helps the understanding of the experimental results and reasonable agreement is obtained .