Recycled fiber provides many benefits to our environment. It can also have an adverse effect on a papermaker’s energy efficiency and production goals. When paper made with recycled fiber reaches the dryer section, it brings along unfilterable glues, adhesives, and chemicals contained in the yet to be evaporated moisture of the sheet. And this is when problems arise. As the sheet moisture is evaporated, chemicals are released and adhere to the dryer cylinder surface which transfers them to the dryer fabric. In a short time, stickies combine with fibers pulled from the sheet and accumulate into dryer fabric surface deposits that come between the sheet and dryer surface. This creates an additional resistance to heat transfer and forces the operator to slow the paper machine to achieve desired sheet dryness and often negatively impacts sheet CD moisture profile and creates additional production challenges.
To deal with the issues caused by dryer fabric stickies, there are many fabric cleaning options ranging from standard needle showers and chemical showers to traversing shower heads with a range of pressure and nozzle options. When it comes to recycled fiber paper machine dryer fabric cleaning, high-pressure traversing showers have been shown to be the most reliable and efficient option for cost-effective cleaning of dryer fabrics.
The shower head nozzle arrangement is designed to effectively remove fabric surface deposits and debris from the interior weave of the dryer fabric. This allows for maintaining the designed fabric openness critical to sheet moisture evaporation and efficient drying. In more advanced systems, such as the M-clean™ cleaning system, an active vacuum-assisted debris removal system ensures stickies and debris are removed from the process while the air knife and optimized nozzle with proper water flow ensure no moisture streaks remain in the cleaned area of the fabric. With the M-clean cleaning system, the common practice is to clean dryer fabrics once per eight-hour shift. As a result of fewer cleaning cycles compared to other fabric cleaning methods, the mill’s water and energy consumption is significantly reduced over the life of the product.
In a recent installation of three M-clean™ cleaning system at a linerboard mill in the U.S., the ROI was found to be less than one year due to increased production (records have been set), faster machine speeds (records have been set), and improved quality from a significant improvement in CD moisture profile and CD basis weight profile as fiber is no longer being pulled from the sheet by dryer fabric stickies. Similar results have been experienced by recycled fiber linerboard and corrugated medium mills in Louisiana, Wisconsin, Ohio, Virginia, and New York.
About the Guest Author
Dave Behrens is the North America M-Clean Sales Director for Kadant. Prior to joining Kadant in 2003, he spent nine years working in paper machine clothing applications engineering and technical sales. Earlier in his career, Dave worked as a paper machine superintendent at a 100% recycled fiber corrugated medium paper mill where dryer fabric cleanliness was a daily challenge. “If only I had the M-clean cleaning system on my machine, I may never have left the mill.”