Chemical process control practice — Some examples and observations

In a recently commissioned plant the process control team at Perstorp has been actively involved in improving controls for many different subprocesses, and also in selecting plant wide control strategies. Here we describe in some detail a few examples where proper selection of control structure for multivariable subprocesses has had a big impact on how the plant operates, and raise some questions which may provide inspiration for future academic research. Examples of processes controlled are distillation columns, heat exchangers and reactors.