# Laboratory experiment: Residence Time Distribution (Cascade)

## Task

The residence time distribution of a cascade of continuously stirred tank reactors and a flow reactors is to be measured in a total of 6 experiments (V1-V6) at the following volume flows:

Cascade | Flow Reactor |
---|---|

V1 = 80 ml/min | V4 = 80 ml/min |

V2 = 150 ml/min | V5 = 150 ml/min |

V3 = 300 ml/min | V6 = 300 ml/min |

For this purpose a pulse of a coloured salt solution (KCl) will be added to the system as a tracer (t=0). The changes to the salt concentration (${\mathrm{dc}}_{\mathrm{A}}$ /dt) will be measured by means of conductivity. The volume (${V}_{\mathrm{R}}$) of one continuously stirred tank reactor is 144 ml and that of the flow reactor is 188 ml.

The following analyses are to be performed:

1.) Cascade - for V1 - 3: Calculation (a) and graphical determination (b) of the mean residence time τ Comparison of methods (a) and (b). Discussion about the influence of the volume flow on the mean residence time

2.) Cascade - for V2 und V3: Determination of the equivalent tank in series number for tank 3 and 4. Discussion of the results. Discussion about the influence of the volume flow.

3.) Flow Reactor - for V4 - 6: Discussion of the curves (location, maximum, shape). Discussion about the influence of the volume flow.

4.) Flow Reactor - for V4 - 6: Determination of the equivalent tank in series number. Discussion of the results. Discussion about the influence of the volume flow

5.) Sum Curve - for V2 and V5: Determination of the sum curve discussion of the results. Comparison of the sum curve of tank1 and of the flow reactor.