Damaged pressure vessel caused dangerous situation at UPM Kaukas pulp mill

​(UPM, Lappeenranta, 28 October 2016 at 11:20 EET) – A dangerous situation occurred at the UPM Kaukas pulp mill in Lappeenranta, Finland, late Thursday, 27 October, 2016 when damaged post-digester on the sawdust cooking line resulted in an uncontrollable pressure pulse on the mill floor.

There are three cooking lines at the Kaukas pulp mill: conifer and birch cooking lines and a separate, smaller cooking line for sawdust. Pulp cooking takes place under high pressure and at high temperatures. According to General Manager Teuvo Solismaa, the incident did not involve an explosion, but damaged pressure vessel resulted in a pressure pulse on the mill floor that caused material damage. The pressure vessel was inspected in 2015 and no defects were found. The wall thickness of the post-digester was also inspected and found to comply with standards.

“The incident had no environmental impacts and the area was quickly restricted. Pulp and cooking chemicals leaked onto the mill floor, from where they continued their normal route to the wastewater treatment plant,” explains Minna Maunus-Tiihonen, Environmental Manager at UPM Kaukas.

The incident will be treated as a potentially serious dangerous situation. “The important thing is that there were no injuries to personnel or any environmental damage. We don’t know the reason for the incident yet but it will be investigated in compliance with the requirements of the Finnish Safety and Chemicals Agency (Tukes),” says Teuvo Solismaa.

Currently the sawdust cooking line is non-operational and the area is being cleaned. It is too soon to tell how long its operation will be suspended. “Sawdust cooking is a minor part of our pulp production. The pulp mill is otherwise operating normally so the incident has only a minor impact on our overall pulp production,” says Solismaa.

More information:
Teuvo Solismaa, General Manager, UPM Kaukas, +358 40 7411 380, teuvo.solimaa@upm.com