Intermediate sections material balance equation

Therefore, for the intermediate sections, the equations of material balance should be transformed in such a way that the flow rate and composition of a pseudoproduct - that is, the difference between the outgoing and the incoming flows - should be substituted there for the flow rate and composition of the product. Figure 6.1 shows an example of a closed contour for obtaining material balance equations for the intermediate section. 

Figure 6.1. A complex column with two feeds and one side product. Control volume (dotted line) for obtaining material balance equations for the intermediate section.

We now express the parameter E/D through x), with the help of material balance equation of the intermediate section (Eq. [6.3]). After transformations, we get the following ... 

A third approach is suggested by Hugo s formulation of material balances at the limit of bulk diffusion control, described in Section 11.3. Hugo found expressions for the fluxes by combining the stoichiometric conditions and the Stefan-Maxvell relations, and this led to no inconsistencies since there are only n - 1 independent Stefan-Maxwell relations for the n fluxes. An analogous procedure can be followed when the diffusion is of intermediate type, using the dusty gas model equations in the form (5.10) and (5.11). Equations (5.11), which have the following scalar form ... 

The system of the equations for the componentwise discrepancies of the material balance in the feed cross-section is solved for the set value of CT = R/Rmm. determining the more precise values of little concentrations of the non-key impurity components in the separation products and of tray numbers in the column sections. The difference of that from the corresponding step of the algorithm for intermediate splits consists of the fact that tray numbers in the sections are included into the number of independent variables besides the concentrations of the non-key impurity components in the separation products. In accordance with that, it is accepted that the concentration of each component in the feed cross-section is a Unear function not only of the little concentrations of the non-key impurity components in the corresponding product, but also of the tray numbers in the corresponding section ... 

The intermediate hopper acts as a storage balancing the inventory change. Evidently there is essentially no inlet and outlet effect, inasmuch as the voidage curves taper off into their respective asymptotic values for both the top and bottom sections of the fast column. This simple boundary condition facilitates flow modeling and the solution of the hydrodynamic equations. It should also be noted that the acceleration zone for the materials tested is too short to call for consideration. 

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See also in sourсe #XX -- [ ]

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