(143e) Design Alternatives and Control Performance in the Pilot Scale Production of Isoamyl Acetate Via Reactive Distillation

In the present
work, two different Reactive Distillation (RD) designs for the pilot scale production
of isoamyl acetate are studied by means of steady state simulations. In the
first design near stoichiometric amounts of acetic acid and isoamyl alcohol are
fed directly to the reactive and rectifying sections of the RD column. On the
second design, acetic acid in excess and isoamyl alcohol are first fed to a
continuously stirred tank reactor (CSTR) and its product stream is fed to the
reactive section of the column. Among different optimization variables, the
overhead vapor flowrate appears to be the most influencing variable in the
energy requirements of the processes, and its value and composition are responsible
for the two liquid phase formation in the condensate. This variable also
determines the global performance of the process schemes yielding a >99%
conversion and >99% isoamyl acetate mass purity of the bottoms product. Having
a CSTR upstream to the RD column allows an operation with a lower overhead
vapor flowrate, thus a lower energy consumption is achieved for this design.

Indirect
composition control of the bottoms product in the direct feed design has been
implemented by controlling the temperature of one of the reactive trays. This
control strategy shows a good disturbance rejection in the dynamic behavior of
the main process variables to variations in the total feed rate and reactant
feed ratio.