Page 258 - Chemical engineering design
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                                            (a)         CHEMICAL ENGINEERING       (b)





























                                            (c)                                    (d)

                           Figure 5.22.  (a) Temperature pattern control. With this arrangement interaction can occur between the top and
                           bottom temperature controllers (b) Composition control. Reflux ratio controlled by a ratio controller, or splitter
                           box, and the bottom product as a fixed ratio of the feed flow (c) Composition control. Top product take-off and
                           boil-up controlled by feed (d) Packed column, differential pressure control. Eckert (1964) discusses the control
                                                          of packed columns
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