The Skoghall pulp mill’s previous filtration technology was originally installed in 1993. Stora Enso Skoghall wanted a technology that would give high availability, while also securing lower suspended solid levels and lowering the mill’s total cost for green liquor handling.
In the spring of 2019, the mill management decided to invest in a Valmet Green Liquor Clarifier G2. The investment also allowed for higher green liquor clarity and lower maintenance costs.
Valmet’s Green Liquor Clarifier G2 technology is a high-capacity clarifier designed for improved flocculation and for full use of the clarifier tank cross-section, this leads to smaller equipment resulting in low capital expenditure when compared to alternative technologies. Furthermore, it has high availability and low power consumption, as well as it requires a minimum of maintenance such as no need for acid washing or filter cloth replacement.
Peter Lindh, Production engineer at Stora Enso’s pulp mill in Skoghall, explains how the new clarifier has helped the mill’s operation. “With our previous filter technology, we needed to change the filter fabrics for the lime mud filter and white liquor filter frequently because of clogging, now with the new Valmet clarifier we have no problems at all. The need for acid washing of the white liquor filter has decreased and our filter fabrics have a longer lifetime.”
“The performance of the new clarifier is good. It has high availability, it’s easy to operate, and requires quite low maintenance. It also has cheap running costs, compared to our previous filtration technology,” concludes Mats Lundstedt, Project Manager at Stora Enso Skoghall.
The project was delivered on time and the execution was smooth through engineering, delivery, construction, and start-up.
“This project was managed well by both the Valmet and Stora Enso project organizations. We have experienced good cooperation and project implementation by Valmet during the entire project, and there has been a give-and-take approach on a level that has worked well for both parties. There are always things that can be improved, of course, but we are happy with both the project implementation and the product. We have met the goals we had set, which was very important to us,” concludes Mats Lundstedt. “Overall, this is a good textbook example of successful project management.”