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Introduction to Reactor Design Fundamentals for Ideal Systems  265































                                                 Figure 5-3. The batch reactor.




                                Assume δV  to be V  (i.e., the volume of the fluid in the reactor),
                                           R
                                                    R
                              the total reactor volume. Suppose that at time t = 0, the number of
                              moles of A in V  = N AO , and at time t = t, the number of moles of A
                                             R
                              in V  = N .
                                  R
                                        A
                                The rate of reaction (–r ) also varies with time t, since the con-
                                                       A
                              centration C  changes with time. Using Taylor’s series y = f(t), gives
                                         A
                                                         2
                                 (
                                         f t)
                                 ft +δ t)= ( +  df t ( ) δ t +  df t ( ) δ t 2  +.....    (5-2)
                                                              •
                                                dt       dt 2   2
                              when δt is small, terms containing δt become negligible.
                              time                              t                    t +  δt
                                                                                N +  dN A  δ
                              Moles of A in V R                N A                A   dt  t +.....
                                                                                      − ( dr A )
                              Net rate of reaction of A        (–r )           − ( r A )+  + t δ  ....
                                                                 A
                                                                                      dt
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