Paper Machine Control

Effective operation of the paper machine can be extremely difficult.

The basis weight and moisture content are very sensitive to small changes in the feed system and are tightly coupled. Production rate changes must be based on very accurately timed changes in thick stock flow, speed, and dryer pressure to avoid upsets. Upset conditions can easily cause a sheet break resulting in lost production.

Implement our proven, advanced paper machine control strategy.

With Emerson's DeltaV™ distributed control system (DCS) we can implement an adavnced paper machine control strategy that stabilizes the sheet machine direction basis weight and air dry content by employing a model-based, multivariable control strategy. The model is based on machine speed, thick stock flow, headbox pressure or level, and dryer pressure and can easily be extended to include disturbances such as broke addition.

Features:

Maximizing production is inherently included, so that the system will automatically default to air dry control over basis weight control if the process is dryer limited
Fully automated production ramping is included
Disturbance rejection is a key part of the system
Intelligent use of scanner data is built into the system
Flexible use of smart instrumentation is part of the design
Model deadtime varies based on the production rate, so that as the machine slows down, the feedback slows
Model predictive and expert system logic for decision-making provides flexibility and the ability to respond effectively to the widest possible variety of real-time conditions