The dryer section of the paper machine at Rhein Papier paper mill in Hürth, Germany, saves energy via new software control.

The Siemens Industry Solutions Division, Erlangen, Germany, has developed software with an energy-saving control strategy for dryer sections.

The Sipaper APC (Advanced Process Control) DrySec reduces steam consumption in papermaking by decreasing energy needs in the drying process. Optimized setpoints are calculated for all drying parameters and adjusted to actual process conditions. The system was piloted successfully at the Rhein Papier GmbH’s paper mill in Hürth near Cologne, Germany, reducing the main steam requirement by more than 3 percent, according to Siemens.

Utilizing steam to dry paper accounts for a large portion of the energy costs in the paper industry. The Sipaper APC DrySec’s main focus is on air requirements, heat recovery, steam, and the condensate system. Measured values are used to adapt the model at regular intervals to current process conditions.

The system also ensures that water evaporating from the paper web is exhausted continuously without condensation. Depending on the type of paper machine, other parameters can be calculated such as the heat curve, the heating of the white water and the quantity of steam in the steam box.

The software can be used as a soft sensor because it calculates process variables for which no instrumentation is installed. This includes, for example, the moisture content and temperature of the paper web upstream and downstream of each drying cylinder, and the energy consumed in the heat exchanger, which leads to a better understanding of the plant.