Page 179 - Elements of Chemical Reaction Engineering 3rd Edition
P. 179

Sec. 4.3   Tubular Reactors                                    151

                                        Gas phase, constant T and P:


                                                         u=u0-= FT   uo(l+EX):
                                                               FTO
                                                                             1-x
                                                                                            (EI-4.3)

                                                                   cx
                                                             c  -AO                         (Et-4.4)
                                                                - (1 +EX)
                                     4.  We now combine Equations (E4-4.1) through (E4-4.3) to obtain

                    Combining the             =     X        dX         =
                   design equation,                   kCA0 (1 - x)/ (1 + EX)   0 kCAO(1-X)
                     rate law, and                                                          (E41-4.5)
                     stoichiometry                    (1 +EX)dX


                                        Since the reaction is carried out isothermally, we can take k outside the inte-
                                        gral sign and use Appendix A.l  to cany out our integration.


                 Analytical solution


                                     5. Parameter evaiuation:




                                             = 0.00415 -
                                                     lb mol
                                                       ft3

                                                      E = yAos = (1)(1+  1 - 1) = I

                                       We need to calculate k at 1100 K.







                                                                                            (E4-4.7)

                                                  0.072      82, OOO caVg mol( 1100 - 1OOO) K  1
                                                           1.987 cal/(g mol * K)( lo00 K)( 1 100 K)
                                                                                         _I
                                                = 3.07 s-I
                                       Substituting into Equation (E4-4.6) yields
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