Levenspiel plot

Plots of l/-r vs. X are sometimes eefeaed to as Levenspiel plots (after Octave Levenspiel)... 

CDP2-A Use Levenspiel plots to calculate PiFR and CSTR reactor volumes given -Ta (Includes Solution) [2nd Ed. P2-12bJ... 

CDP2-Ca Use Levenspiel plots to calculate PFR and CSTR volumes. 

Figure 2-9 Levenspiel plot showing comparison of CSTRs in series with one FFR,...

Figure 2-11 Levenspiel plot 10 determine the reactor volumes Fi, V . and Vj,...

In the segiiencins of rettcfors one is often asked. "Which reactor should go lirsi to give the highest overall conversion Should it be a PFR followed by a CSTR. or two CSTRs, then a Pre, or The answer is It depends." It depends not only on the shape of the Levensptel plots (Fac/ a) versus X, but also on the relative reactor sizes. As an exercise, examine Figure E2-7.2 to learn if there is a better way to arrange the two CSTRs and one PRF. Suppose you were given a Levenspiel plot of vs. X for three reactors... 

Levenspiel plot of (J/-rj,) a function of nutrient conversion Jfs = (Cjo -CjVCso is given below in Figure P2-8. 

CDP2-Db Use Levenspiel plots to calculate PFR and CSTR volumes. (PDF) (3rd Ed. P2-91... 

CDP2-F, Use Levenspiel plots to calculate CSTR and PFR volumes for the reaction A + B - C. 

However, instead of using a Levenspiel plot, we will most likely use Polymath to solve our coupled differential energy and mole balance equations. 

One can readily see why the reactor volume for 40 conversion is smaller for a CSTR than a PFR by recalling the Levenspiel plots from Chapter 2. Plotting as a function of X from the data in Table E8-3-1 is shown here. 

Levenspiel plot. We are now going to carry out a number of examples where we have specified the flow rate at 0-4 mol A/s. 

We are now going to use the Levenspiel plot of the processed data (Figure 2-2B) to size a CSTR and a PFR. 

Analysis Given the conversion, the rate of reaction as a function of conversion along with the molar flow of the species A, we saw how lo calculate the volume of a CSTR. Prom the data and information given, we calculated the volume to be 6.4 m3 for 80% conversion. We showed how to cany out this calculation using the design equation (2-13) and also using a Levenspiel plot. 

Levenspiel plot for this reaction is shown in Figure P2-I0b-... 

We could now use a Levenspiel plot to find the catalyst weight W in a packed-bed... 

Closure. Having completed this chapter, you should be able to write the rate law solely in terms of cmiversion and the reaction rate parameters, (e.g., k, Kq) for both liquid phase and gas phase reactions. Once express-ing -r = J[X) is accomplished, you can proceed to use the techniques in Chapter 2 to calculate reactor sizes and conversion for single CSTRs, PFRs and PBRs, as well as those connected in series. However, in the next chapter we will show you how to carry out these calculations much more easily without having to resort to Levenspiel plots. After studying this chapter you should also be able to calculate the equilibrium conveTsitHi for both constant volume batch reactors and for constant pressure Row reactors. 

We can use this sequence to prepare a table of (Fao -ta) as a function of X. We can then proceed to size PI s and CSTRs. In the absolute worst case scenario, we could use the techniques in Chapter 2 (e.g., Levenspiel plots or the quadrature formulas in Appendix A). However, instead of using a Levenspiel plot, we will most likely use Polymath to solve our coupled differential energy and mole balance equations. 

Coniinuitig in this manner for other conversions, we can complete Table El 1-3.1. Use the data in Table El 1-3.1 to make a Levenspiel plot, as in Chapter 2. 

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