The Iggesund Workington board mill in the UK has successfully applied a Valmet IQ Moisturizer in board production to achieve higher production rates especially with higher grammage products.
We are more than satisfied, stiction is improved and we have been able to increase machine speed by several percent, especially with the heavier grades where drying after the MG was a problem.
Rolf Moring, Iggesund Workington’s development engineer
Summary
Location
Workington, U.K.
Challenge
The common control method for surface moisture and release line is to adjust the pre-dryer steam pressure, but naturally this method not only affects surface moisture but the total moisture of the sheet. As the drying process continues on smaller cylinders, too high web moisture after the MG cylinder can limit machine speed with post-drying a bottleneck to increased production.
The mill was struggling with the limited drying after the MG cylinder but had more than enough capacity in the pre-drying.
The Valmet IQ Moisturizer now provides the potential to run heavy grammage products faster by fully utilizing pre-drying before the MG cylinder. The moisturizer sprays the sheet just before the MG cylinder to give the required sheet surface moisture to stick to the cylinder, without excessive total moisture.
