Dynamic optimisation is a tool that enables the process industries to
compute optimal control strategies for important chemical processes.
Aspen DynamicsTM is a well-established commercial engineering software
package containing a dynamic optimisation tool. Its intuitive graphical
user interface and library of robust dynamic models enables engineers to
quickly and easily define a dynamic optimisation problem including
objectives, control vector parameterisations and constraints. However,
this is only one part of the story. The combination of dynamics and
non-linear optimisation can create a problem that can be very difficult
to solve due to a number of reasons, including non-linearities, poor
initial guesses, discontinuities and accuracy and speed of dynamic
integration. In this talk I will begin with an introduction to process
modelling and outline the algorithms and techniques used in dynamic
optimisation. I will move on to discuss the numerical issues that can
give us so much trouble in practice and outline some solutions we have
created to overcome some of them.