Residence Time Distribution of a Blast Furnace

The deviation of the blast furnace from plug flow behavior can be described by the tanks-in-series model (Section 4.10.5) or by the dispersion model (Section 4.10.6). 

For example, a Damkoehler number Da of 4 would lead to a conversion of 98.2% in a PFR. In the blast furnace [Eq. (6.5.25)], almost the same value of 97.7% is reached. Thus the blast furnace can almost be regarded as an ideal plug flow reactor. 

Dispersion Model For a small extent of dispersion (Bo 50), the variance cr characterizing the width of the residence time distribution is given by Eq. (4.10.102)  

105) we can then also calculate the numbers of tanks-in-series N  

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