Page 298 - Modeling of Chemical Kinetics and Reactor Design
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268    Modeling of Chemical Kinetics and Reactor Design

                                      C AF  dC
                                 t =−  ∫    r − (  A )  =,  for ε  = 0                   (5-17)
                                             A
                                      C AO
                                Equations 5-12, 5-16, and 5-17 are the performance equations for
                              a batch reactor.
                                When the volume of reacting mixture changes proportionately with
                              conversion, as in the case of gas phase reactions, this implies working
                              volume changes with time,



















                              and Equation 5-12 becomes

                                 V = V (1 ε   X )                                        (5-18)
                                          +
                                  R    O    A  A
                              where V  = initial volume of the reactor
                                      O
                                    V  = volume at time t
                                      R
                                       X AF       dX           N   X AF     dX
                                  =
                                                    A
                                 tN  AO ∫    r − (  V ) (1 ε  X )  =  AO  ∫  r − (  A  X )
                                                     +
                                         0    A   O    A  A    V O   0    A ) + (1 ε A  A
                                       X AF
                                  =  C AO ∫  r − (  dX A  X )                            (5-19)
                                         0    A ) + (1 ε A  A

                              where  ε  is the fractional change in volume of the system between
                                     A
                              no conversion and complete conversion of reactant A given by
                                     V X A =1  −  V X A =0
                                 ε =
                                  A                                                      (5-20)
                                         V X A =0
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