New Digester Top Separator Ensures Long-Term Reliability for Södra Cell Mönsterås

The decision to install the new separator was taken after a mechanical lifecycle analysis conducted by Valmet during the mill's annual shutdown in 2022 revealed significant structural deficiencies in the existing digester top, which had been in continuous operation since 1979. These included material degradation, corrosion, and stress fractures. These findings, along with the results of a third-party inspection, underscored the need for a proactive upgrade to maintain safe and efficient operations.

Keeping our machine line in good condition is key to creating a safe work environment for our employees and further improving our performance. Thanks to Valmet’s lifecycle analysis, the digester top separator will now be renewed on time, contributing to the safety and reliability of the machine line,” says Johan Carlstroem, Maintenance Engineer at Södra Mönsterås.

Precise and Efficient Execution

The installation was completed within the planned 12-day outage window, minimizing production downtime. The project required coordination across multiple disciplines, including scaffolding, insulation, piping, platforms, and heavy lifting.

Christian Mitander, Project Manager at Valmet, highlights the meticulous planning behind the project:

 The execution included machine equipment delivery, engineering, site planning, and installation. Despite the height and weight challenges, the new digester top was installed within the planned timeframe.”

Enhancing Safety, Efficiency, and Sustainability

Södra Cell Mönsterås is one of the world’s leading producers of paper pulp, with an annual production capacity of 750,000 tons of softwood and hardwood pulp. The mill also plays a key role in green electricity generation. With this upgrade, Södra Cell ensures continued production reliability and increased workplace safety by eliminating the risks associated with steam and white liquor leaks.

With our experience, we can help ensure customer assets operate safely, efficiently, and sustainably,” says Robert Carlström, Global Technology Manager, Chemical Pulping at Valmet.

Projects like this demonstrate Valmet's expertise in lifecycle analysis and ability to execute complex modernizations based on these analyses. The successful cooperation between Valmet and Södra Cell Mönsterås ensured smooth execution and an outcome that enhances safety, efficiency, and sustainability at the mill.

The project was a great success, and the open and transparent cooperation between Valmet and Södra Cell ensured that it was executed smoothly and on time,” concludes Carlstroem.

Key Technical Details

• Modern design tailored for the mill’s digester 4
• The upgrade included enhancements to process piping, gearbox, electric motor, and access platforms
• Installation height: 64 meters
• Total weight: 75 tons