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Levenspiel Plot

When designing ideal reactors it is possible to use experimental rate data to calculate the volume required. Based on conversion the reactor volume can be given by,

CSTR PFR
V=FA,0rAX V=X0FA,0rAdX

This means that if FA,0/rA is plotted against the conversion X then the volume of a CSTR is given by the rectangle from the exit conversion to the inlet conversion, whereas the volume of a PFR is given by the area under the curve.

The graph below shows the volume of 2 reactors in series. For a PFR the total volume is always the same, but sensible selection of the intermediate conversion for the CSTRs can reduce the total reactor volume.

Xm
0.4
PFR 1 volume = 0.494 m3, CSTR 1 volume = 0.667 m3
PFR 2 volume = 0.836 m3, CSTR 2 volume = 1.4 m3
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Levenspiel PlotConversion exit reactor 1Conversion exit reactor 2XF​A0/-r​A / m​3