Journal of Environmental Science International (한국환경과학회지)

The Korean Environmental Sciences Society (한국환경과학회)
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Journal of the Environmental Sciences A Study on the Operating Conditions to Eliminate Feedpipe Backmixing for Fast Competitive Reactions

  • Jang, Jeong-Gook (Department of Energy Environmental Engineering, Dongseo University) ;
  • Jo, Myung-Chan (Department of Advanced Materials Engineering, Dongseo University)
  • Received : 2011.02.09
  • Accepted : 2011.07.21
  • Published : 2011.08.31
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Abstract

A novel conductivity technique was developed to detect penetration depth of the vessel fluid into the feedpipe. For a given reactor geometry, critical agitator speeds were experimentally determined at the onset of feedpipe backmixing using Rushton 6 bladed disk turbine (6BD) and high efficiency axial flow type 3 bladed (HE-3) impellers. The ratio of the feedpipe velocity to the critical agitator speed ($v_f/v_t$) was constant for either laminar or turbulent feedpipe flow regimes. Compared to the results of fast competitive reaction, feedpipe backmixing had to penetrate at least one feedpipe diameter into the feedpipe to significantly influence the yield of the side product. However, higher $v_f/v_t$ than that for L/d = 0 (position at the feedpipe end) of the conductivity technique is recommended to completely eliminate feedpipe backmixing in conservative design criteria. The conductivity technique was successful in all feedpipe flow conditions of laminar, transitional and turbulent flow regimes.

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References

  1. Belevi, H., Bourne, J. R., Rys, P., 1981, Mixing and fast chemical reaction-II, Chem. Eng. Sci., 36, 1649-1654. https://doi.org/10.1016/0009-2509(81)80009-7
  2. Bhattacharya, S., Kresta, S. M., 2006, Reactor performance with high velocity surface feed, Chem. Eng. Sci., 61, 3033-3043. https://doi.org/10.1016/j.ces.2005.10.070
  3. Bourne, J. R., Kozicki, F., Rys, P., 1981a, Mixing and fast chemical reaction-I, Chem. Eng. Sci., 36, 1643-1648. https://doi.org/10.1016/0009-2509(81)80008-5
  4. Bourne, J. R., Kozicki, F., Moergeli, U., Rys, P., 1981b, Mixing and fast chemical reaction-III, Chem. Eng. Sci., 36, 1655-1663. https://doi.org/10.1016/0009-2509(81)80010-3
  5. Bourne, J. R., 1982, The characterization of micromixing using fast multiple reactions, Chem. Eng. Comm., 16, 79-90. https://doi.org/10.1080/00986448208911087
  6. Bourne, J. R., Rohani, S., 1983, Micro-mixing and the selective iodination of 1-tyrosine, Chem. Eng. Res. Des., 61, 297-302.
  7. Fasano, J. B., Penney, W. R., 1991, Cut reaction by-products by proper feed blending, Chem. Eng. Progress., 87, 46-52.
  8. Fasano, J. B., Penney, W. R., Xu, B. C., 1992, Feedpipe backmixing in agitated vessels, AIChE. annual meeting, 111C.
  9. Jo, M. C., Noh, B. I., Kim, J. H., Shin, C. H., 1997, Detection of feedpipe backmixing by conductivity technique, J. Ind. Eng. Chem., 3, 318-325.
  10. Kresta, S. M., Wood, P. E., 1991, Prediction of the three-dimensional turbulent flow in stirred tanks, AIChE., 37, 448-460. https://doi.org/10.1002/aic.690370314
  11. Rice, R. W., Baud, R. E., 1990, The role of micromixing in the scale-up of geometrically similar batch reactors, AIChE., 36, 293-298. https://doi.org/10.1002/aic.690360217
  12. Taylor, R. A., Penney, W. R., Vo, H. X., 2005, Scale-up methods for fast competitive chemical reactions in pipeline mixers, Ind. Eng. Chem. Res., 44, 6095-6102. https://doi.org/10.1021/ie040237u
  13. Vicum, L., Ottiger, S., Mazzotti, M., Makowski, U., Dyga, J. B., 2004, Multi-scale modeling of a reactive mixing processing in a semibatch stirred tank, Chem. Eng. Sci., 59, 1767-1781. https://doi.org/10.1016/j.ces.2004.01.032