Following its rebuild and start-up in October 2023, PM 4 at DS Smith's Viana Paper Mill reached final acceptance. The rebuild has increased production from 400,000 tons to 430,000 tons of kraftliner and high-performance top kraftliner per year, at a design speed of 1,200 m/min. This improves the plant's overall efficiency and further strengthens its position as market leader in Southern Europe.
The rebuild included modifications of the wire section, a completely new press section and upgrade of web transfer between the press and dryer sections. In addition, modernizations in stock preparation were part of the rebuild. The forming section scope comprised new dewatering elements, a high-pressure water jet edge trim cutter from the Prevo family and a suction reversing roll for the top wire. A new Tandem NipcoFlex press outfitted with QualiFlex Crown sleeves and modifications for the web transfer to the dryer section made up the scope of the press section rebuild. A comprehensive fabrics package including I-Series forming fabrics, Vector and Infinity press felts and Jade dryer fabrics were supplied for the start-up and optimization phase of PM 4, including services and spare parts. With machine safety in focus, the press section was additionally supplied with ProTect, enabling safe and reliable felt profile measurements.
In combination with Voith services and spare parts, the rebuild achieved 15 percent specific steam savings with an increase in production and almost 90 percent fewer paper breaks due to fly-off in the wire section. Driven by sustainability, the rebuild objectives of increasing the overall efficiency and production of the machine at lower energy consumption were fully achieved.
"We are very satisfied with the results achieved. The promised dry contents after the press were achieved for all grades, helping us meet our ‘Now & Next’ decarbonization targets by reducing energy consumption and producing kraftliner more sustainably and efficiently," said Eduardo Fernandes, Project Manager at DS Smith. "The results after the rebuild speak for themselves,” said Philip Schnellinger, Process Technology Manager at Voith Paper. “Our full-line solutions are having the desired effect on the overall efficiency of the process line and consumption of resources during production. This success was made possible by the selection of the right concept and the close and trustful cooperation between the two teams."