Plant-Wide Control of Vinyl Acetate Monomer Unit

Dynamic simulation and control of azeotropic distillation tower in Vinyl Acetate Monomer (VAM) plant is one of the most important problems in this plant, because careful performances on this part of the plant will have positive effects on the other part of the process.

In this paper was concentrated on the control of azetropic distillation tower of VAM unit. A new arrangement has been chosen for the control of liquid level in the reboiler and control of liquid level in the evaporator by manipulating the recycle stream and entering acetic acid stream to the process respectively. The major point in this strategy is the heat used in the evaporator was constant, which will ensure that the amount of feed flow to the reactor was guaranteed. Therefore by employing this strategy the oscillations on liquid flow will degrade and will lead to stability of control variables.

Also in this work by using a nonlinear neural network predictor, it has been shown that the response time to a define change in the setpoint of waste product concentration, compared with previous methods has been greatly reduced and the setpoint was tracked with a suitable dynamics and more reasonable overshoot.