Modeling techniques for integration of process systems

Increasing social, economic and environmental pressure force the process industry to look for new ways to improve the overall operation of their process systems.Since these systems are operated at different levels of decision (apparatus, plant, enterprise, etc.) integration of the different levels is expected to lead to significant improvements in system efficiency (energy, waste, costs, quality, product distribution, logistics, etc). Integration also results in increased mathematical complexity that can not be handled with the current numerical methods. This leads inevitably to a paradox: the integrated problem needs to be decomposed again into simpler sub-problems that are solved independently providing sub-optimal solutions. This paper will discuss why integration fails and which steps are needed to break the paradox. Focus will be on new modeling techniques for the different decision levels.