Perfectly mixed flow reactors about

The apparatus consisted of a flow reactor containing the coal and an oxygen absorber. A fixed bed reactor was used for studies on large coal particles, while a spout reactor was used for studies on small coal particles. Both reactors had a volume of about 400 cc. and were designed so that both wall and end effects were eliminated. Experimental residence time distributions indicated that the fixed bed reactor approximated a plug flow reactor, while the fluidized bed spout reactor had perfect mixing. 

One of the clearest demonstrations of how difficult it is to obtain perfect mixing in a CSTR is found in the studies of Menzinger and Dutt (1990) on the chlorite-iodide reaction. These authors placed a platinum microelectrode at different distances from the central stirring rod in their cylindrical flow reactor. In one experiment, at a stirring rate of 880 rpm, consistent with many well-stirred CSTR experiments, they observed a difference in electrode potential of about 50 mV when the electrode was moved radially from a position at the axis to a position 12 mm away in the radial direction. This difference corresponds to a... 

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