with virtual sensors by Voith

Optimizing the paper manufacturing process with virtual sensors: the story of ondi u omberok in lovakia

Article by Julia Schaefer, Global Market Communication Manager, Voith Group

Meeting the challenges of the paper industry with digital solutions has been an issue addressed by some papermaking machinery suppliers for quite a while now. The sensor technology has proven useful in that respect. ith its On ficiency. trength concept applied to PM 18 at Mondi C u omberok in lovakia Voith helped his client achieve some impressive results.

The price of raw material is forcing paper manufacturers to reduce production costs and further improve the efficiency of their production facilities. In this context, digitalization is the key technology for achieving efficiency increases and cutting costs, because ne technologies in particular enable significant improvements in existing and new facilities. hey allo better monitoring of all processes and therefore more precise production control, hich in turn results in higher efficiency and better availability.

REDUCED FIBER CONSUMPTION

ince fiber is a decisive cost factor in paper production, the goal of papermakers is to reduce fiber losses and minimi e the amount of fiber as much as possible ithout falling belo the re uired uality level. o ever, optimization with conventional measures and tools has its limits, and in many cases, papermakers

Fig. 1: The use of nE ficiency. trength at PM 18 allowed 2,800 metric tons of virgin fibers to be saved in the first year, while important uality parameters li e bending stiffness and thic ness remained within target values.

ig 2: nE ficiency. trength helps stabili e uality uctuations and reduce costs.

are faced with the situation that they simply cannot control important uality parameters such as strength in a closed loop. Digital solutions li e n fficiency. trength by oith no offer the possibility to constantly eep trac of ey uality parameters to minimi e the amount of fibers.

O MO D S C R OM ERO S OPTIMIZING FIBER CONTENT

e have been usin On fficiency.Stren th since 2018 to consistently meet uality re uirements for stiffness and thickness and thus optimi e the paper produced on the M 18, says Peter Chlepko, Manager of the PM 18 at ondi u ombero . In the process e are also reducin our costs, because On fficiency.Stren th provides optimum control of basis ei ht and ash content.

hat is other ise only possible using manual measurements in elaborate measuring processes and ith considerable additional effort is no being done at u ombero ith virtual sensors that calculate the data on bending stiffness. his continuous condition monitorin of key uality parameters enables automated ad ustment of the paper eb’s fiber and ash content, hereas manual laboratory measurements can take up to 0 minutes to deliver results after samplin , and the parameters can only be ad usted by means of manual interventions, says Dr. Julius Flitsch, Director Remote perations enter at oith aper. hanks to the virtual sensors, stren th values are available in real time, so fiber content and basis ei ht can be reduced ithout any time delays. he filler content, also kno n as ash content, can be increased to achieve the re uired stren th values.

fter e installed On fficiency.Stren th, the basis ei ht and the ratio of fiber to ash improved substantially, says Chlepko. s a result of this advanced process control system, e could stabili e our paper manufacturin process and are no able to proactively control paper uality. his means e can achieve the re uired paper uality even ith a hi her ash content and lo er basis ei ht, as confirmed by our laboratory measurements.

he picture belo sho s the process stabili ation achieved at in u ombero through the installation of the n fficiency. trength control system. Following an optimization phase, the basis eight as reduced by around 0.5%. At the same time, the ash content was increased by . , the ratio of fiber to ash op-

ptimi ation o ash and basis weight ratio or the in u ombero .

timi ed and the entire process stabili ed, eeping the uality stiffness above the specified level.

he real time prediction of uality parameters and the continuous optimization of the process not only prevents uality uctuations. n fficiency. trength also enables production costs to be reduced hile reliably maintaining uality. e reduced our costs because of better prediction and faster ad ustment of ash content to chan ed process conditions, hile maintainin all uality parameters, says Chlepko. As a result, the use of n fficiency. trength in the allo ed , metric tons of virgin fibers to be saved in the first year, hile important uality parameters li e bending stiffness and thickness remained within target values.

E O E C E C .S RE R C E S A E, S A E, OPTIMIZE

n fficiency. trength combines three modules into one high-performance control system and heralds a new generation of advanced process control systems. The system includes virtual sensors, also known as soft sensors, the model predictive control unit and the cost optimizer. A special feature of the virtual sensors is their high accuracy, as the prediction accuracy is typically over . oreover, the soft sensors are self adapting and able to eep their prediction accuracy at a very high level.

The virtual sensors accurately predict important uality parameters. he real time knowledge of these values allows the MPC to control the paper manufacturing process in such a way as to consistently achieve the targeted values by means of continuous ad ustment. The cost optimizer then ensures that this is done at the lo est possible cost. n order to find the customer specific cost optimum, actuators and control strategies can be individually selected and e ibly adapted.

ondi u ombero as impressed in particular by the high savings potential offered by n fficiency. trength. his as calculated beforehand in the value add assessment. “Before installin the product, e conduct a value add assessment’ for our customers, hich calculates the savin s potential of On fficiency. Stren th based on individual customer data, says r. litsch of oith. e then uarantee the savin s potential to our customer. In addition, e al ays individually define the parameters and actuators to be controlled dependin on customer re uirements and paper machine.

MO D S C R OM ERO A D O A S CCESS S OR

ondi and oith have been riting their shared success story since as far bac as . he collaboration bet een the t o companies began ith an order for the ne . n , oith rebuilt this production line to create an ultra modern paper machine for office papers. e have had a very ood e perience of orkin ith Voith. lon ith the construction of the M 18, e also successfully completed numerous other pro ects to ether and ere therefore able to continually improve our paper manufacturin process, says Chlepko. Our collaboration ith Voith as al ays at a very hi h level and based on a spirit of partnership. Durin the On fficiency.Stren th pro ect phase, e en a ed in a close, in-depth dialo . s a result, e ere able to discuss potential problems and implement solutions promptly.

e are very proud to be able to look back on an intensive collaboration ith Mondi based on a spirit of partnership, says Andreas Zangl from the oith sales team for u ombero . he re ular personal e chan es in particular are very important for both parties. ith the introduction of a ne eneration of advanced process control systems for the M 18, e have a ain stepped up these e chan es. On fficiency.Stren th is an e ample of ho our customers are continuin to evolve and are able to benefit from the savin s potential offered by our apermakin .0 product ran e.