Control over Kaos – Process Control & Optimisation Methodologies

Norm Laslet

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You don’t need to be Maxwell Smart to control chaos in your process. But, we do need good process design and good process control to ensure that the quality of our product is acceptable to our customers. Process disturbances caused by variability of raw materials, equipment malfunctions and paper breaks must be minimised to keep quality on targets.

To ensure that we make money when producing our products, we must optimise our process targets. This paper presents the case for a greater emphasis on improving our process controls to minimise process variability and to maximise our returns. In most mills the tools exist, but the means to implement the improvements are lacking. The costs are low and the gains are significant, so why aren’t we doing it?


Topics covered in this paper are:

  • The causes of process disturbances and variability.
  • The Opportunities
    • The opportunity to minimise process disturbances and variability.
    • The economic case for improved process control.
    • The economic case for process optimisation.
  • Process Control & Optimisation Methodologies
  • Process system design
  • Control system design
  • Process characterisation
  • Control system tuning
  • Performance monitoring
  • Process troubleshooting

Process control engineering is not an art – it is a science. As in every other field of engineering, design must be methodical and not considered in isolation. Good process design and good control system design go hand in hand. Each control loop must be considered as part of the total process system. Effort is required to achieve good design, appropriate tuning, and ongoing monitoring and maintenance over the life of the asset.


High process variability compromises the economic performance of pulp and paper processes through reduced production, increased operating costs and off-quality product. A control loop that is well designed, maintained and tuned can play a key role in minimising process variability.