An investment of €238m at Iggesund Paperboard in Sweden included a new recovery boiler, a 70MW back pressure steam turbine and measures to reduce emissions.

Solvina Simulators were used for three purposes:

  • 1) Design and tuning of the steam distribution control system
  • 2) Online testing and tuning of the turbine control to assure island operation ability and
  • 3) Operator training

The steam distribution control system (SDCS) was designed to be very simple yet smart. It controls 35 valves with only six PI-controllers, as it uses very effective smart split-functions. The SDCS is able to handle very large variations in steam demand without disturbing the recovery boiler, and the design is adaptable to all types of plants.

In the online test of the Turbine Governor, Island operation capability was verified with a simulator based test method where the turbine generator is connected to the strong national grid during the tests.

A simulator is connected to the turbine controller and forces the controller to respond to the situations of island operation where load changes result in frequency variations.

All operators were trained in a training simulator prior to commissioning, making them aware of the plant’s behavior in all relevant operating situations, and experienced in handling them correctly.