OP-II-3

PP-II-6MODELING OF VINYL ACETATE SYNTHESIS FROM ACETYLENEAND ACETIC ACIDAvetisov A.K.Karpov Institute of Physical Chemistry, Moscow, Russia, avetisov@cc.nifhi.ac.ruThe vapor phase synthesis of vinyl acetate according toC 2 H 2 + CH 3 COOH = CH 2 =CHOCOCH 3usually is performed in a reactor with the fluidized bed of a catalyst (zinc acetate onactivated carbon) in mixtures with excess of acetylene (C 2 H 2 : CH 3 COOH = 4 ÷10) at160-230°C, pressures close to the atmospheric one, and at acetic acid conversionsabout 30%. In order to compensate continuous deactivation of the catalyst and itspartial loss, one continuously increases the temperature in the reactor in such a waythat the total capacity of the unit remains constant. After limiting (with respect to thecatalyst thermal stability) temperature (230°C) is reached, the process is terminated,and the catalyst is replaced by a new one.The object of the present work is to find a theoretically optimum mode (initialtemperature of the process and rate of its elevation, i.e. the unit capacity and cycletime) which should meet the maximum surplus criterion.The kinetics of reaction (А) is described by the equation:kP Pr = 1 21 + b P (1 + b P ), (1)1222where k, b 1 and b 2 are constants, P 1 and P 2 are partial pressures of acetylene andacetic acid, respectively.Under conditions of commercial process (almost constant P 1 , denominator closeto unity) equation (1) transforms intor kP 1 = k'= (2)It was established experimentally, that the catalyst is deactivated according to thefollowing kineticsrPPP/ T )Pda= −dt2 2 02 2d = kda = kdexp( −Ada , (3)11where а is the catalyst activity which represents the ratio of the reaction rate at thestart of the process and at time t. It is supposed that the catalyst loss is described bythe equation(A)345