Multiple side-product draw-offs

Multiple pumparounds Side-stream steam strippers Multiple side-product draw-offs Two-stage overhead system... 

At this input-output level the following assumptions are considered ( ) steady-state modeling (n) multiple feeds (nfeed ), side draw-off streams (notr Z+), heat streams (n, Z+), reactions rirx Z+) and components (uc Z+) and Hi) single bottom and distillate streams. Component and energy balances are performed over the structure. The component molar balances MC) include the distillate, bottom, feed and draw-off streams and the production (or consumption) of species due to chemical reaction. 

The lower part of the column is covered by stepping off stages in a fashion similar to that in the upper part of the column, and the final conni of theoretical stages is then determined. The Ponchon-Savarit method may be used for many situations more complex lhan the simple one just described mixed vapor-liquid distillate product, side draw streams, multiple feeds, and so on. Standard unit operations textbooks should be consulted for more dentils on this methnd. As mentioned, it suffers from a need for enthalpy-concentration data, but even a crude approximation based on linear variation of enthalpy with concentration can be better than the McCabe-Thiele approach if there is a very large difference in the latent heats of vaporization of the iwo components being distillnd. 

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See also in sourсe #XX -- [ ]

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