Chapter 8: Multiple Reactions

Liquid Phase PFR

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POLYMATH report table displaying calculated values of differential equation variables, including initial, minimal, maximal, and final values for variables such as Ca, Cb, Cc, Cd, Fa, Fb, Fc, Ft, reaction rates, and parameters like k1a and k2c.

List of explicit equations including Ft = Fa + Fb + Fc + Fd, k1a = 10, k2c = 15, v = 100, Ca = Fa/v, and Cb = Fb/v.
Equations list: Cc = Fc/v, r1a = -k1a*Ca*Cb^2, r1b = 2*r1a, rb = r1b, r2c = -k2c*Ca^2*Cc^3, r2a = 2/3*r2c, r2d = -1/3*r2c, r1c = -r1a, rd = r2d, ra = r1a+r2a, rc = r1c+r2c, Cd = Fd/v, Scd = if(V > 0.0001) then (Fc/Fd) else (0).

Graph showing the concentration profiles of components (Fa, Fb, Fc, Fd) in multiple liquid phase reactions within a plug flow reactor (PFR). The x-axis represents reactor volume (V) and the y-axis represents molar flow rates.

Graph displaying the profile of Scd in multiple liquid phase reactions within a plug flow reactor (PFR). The x-axis represents reactor volume (V) and the y-axis represents the value of Scd, which decreases sharply and stabilizes over time.

Graph showing Scd profile for multiple liquid phase reactions in a plug flow reactor (PFR) with V=0.001. The x-axis represents reactor volume (V) and the y-axis represents Scd, which decreases sharply and levels off at lower values.

It looks as if the selectivity goes through a maximum, as shown in Figure (A), however, this apparent maximum is a result of numerical inaccuracies at the entrance to the reactor (V = 0) to check if this maximum is real or apparent, we choose a reactor volume at the entrance that is very small 10–3 dm3 and re-run the program, we see in Figure (B) that there is no maximum and that the selectivity decreases as we go down the reactor and the volume increases.

POLYMATH report table showing calculated values of differential equation variables including initial, minimal, maximal, and final values for variables such as Ca, Cb, Cc, Cd, Fa, Fb, Fc, Fd, Ft, reaction rates (r1a, r1b, r2a, r2c, etc.), and parameters like k1a, k2c, Scd, v, and V, where V has a final value of 0.001.




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