increases from 455 K (at 0.8 m from reactor inlet) to 469 K (at 1.2 m from inlet).
The higher temperature results in higher reaction rates, less reactants being recycled.
The gas recycle is the fastest, and the ethylene feed is the fi rst to be adjusted.
Then, more oxygen is added by the concentration controller. The dynamics of the
liquid recycle is slower and it takes about 0.5 hours until the acetic acid feed
reaches the new stationary value. The vinyl acetate production - rate increases from
154 to 171 kmol/h. At time t = 3 h, the coolant temperature is reduced to 400 K,
and the simulation is run for another 2 h. The maximum reactor temperature
drops to 452 K (near the reactor inlet) and the production rate is decreased to
134 kmol/h. During the entire simulation, the oxygen concentration stays very
close to the setpoint of 6%. Moreover, the concentration of the vinyl acetate product
is above the 99.98% specifi cation.