Difference point side rectifiers

The values of vy and Xp may be obtained from an adiabatic flash for a single phase feed or from the constant relative volatility estimated with the converged compositions at the feed stage and feed quality. This procedure can be reformulated for multiple feeds and side products as well as different key components. A pinch point near the feed stage occurs for nearly all binary ideal mixtures. However, for nonideal multicomponent systems, the pinch point exists in rectifying and stripping sections. 

Taking into consideration the symmetry of these sphts, we confine the discussion to the direct split. In the mode of minimum reflux, point x/ should coincide with the stable node A +, and point x/ i should belong to rectifying minimum reflux bundle 5 - Nf (Fig. 5.30). Along with that, Eq. (5.18) should be valid. The search for the value (L/ F) is carried out in the following way at different values (L/V)r, he coordinates of point X/ = Nf are determined by means of the method tray by tray for bottom section and then the coordinates of point x/ i are determined by Eq. (5.18). At(L/F), < (L/F) , points X/-1 and xd are located on different sides from the plane or hyperplane - Nf and, at (L/ V)r > (L/ y)f", these points are located on one side. That finds approximate values (L/ F) (not taking into consideration curvature of bundle 5 - Nf) and approximate coordinates of points X/ i and x/. To determine exact values (L/ F) and coordinates X/-1 and Xf, one varies the values of (LjVjr in the vicinity of found approximate value (L/V)f. Then one realizes trial calculations of top section trajectories by means of the method tray by tray from feed cross-section to the product. If at... 

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