A new scanner, multi-variable controls and a very successful steam profiler
installation ensure top reel quality for Port Townsend Paper. Production
increases of over 10% on a benchmark grade add to the investment return.
The improvement in profiles has been dramatic. The reels are beautiful and you can see there are no ridges. With better profiles the average moisture level has been raised and we meet today’s industry standards across the board. Machine productivity is up as well, and PM 2 sometimes outruns the pulp mill."
Dave Harke, Paper Mill Production Manager (on the left)
Summary
Location
Port Townsend Paper Corporation is located on the shores of Puget Sound in Washington State, United States.
Challenge
PM 2’s quality and profile control capability had not been updated since the early to mid-1990s.
PM2 produces diverse grades with many end users. Versatility means a lot of grade changes and transition periods, so it is vital that customer quality is spot-on every time a specific grade is run and the recurrent changes in grade specs are made as quickly as possible. Flat CD profiles and excellent roll structure are near the top of the quality list.
To maintain a competitive edge and meet today’s more exacting quality control standards, improvements had to be made.
Solution
Quality control upgrades in several steps: The older slice control equipment was upgraded with new electronic controllers with faster and more precise control capabilities, a new higher resolution Valmet IQ QCS system replaced the old Valmet unit, and new multi-variable MD and CD controls and closed-loop automatic grade change controls were implemented. The final addition was a new IQ Steam Profilermoisture profiler which replaced an older steam shower.
Results
The multi-variable CD control has resulted in a “dramatic improvement” in CD moisture profiles as attested by Dave Harke, Paper Mill Production Manager.
Over a two-month period, 2-sigma variability averaged below 0.5% and that is a significant improvement from before-control figures. The precise control by the steam profiler has allowed the mill to turn off the water spray moisture profiling system, thereby saving the energy required to remove the extra water.
Altogether, the improved control and extra dryness from the press has made a major difference in machine productivity as well as quality. Tim Reandeau, machine tender, estimates that the production rates of the benchmark 23-lb medium grade have been increased from 38 to 42 tonnes per hour – slightly better than 10%.
Keywords
Automation, Improvements, Rebuilds and upgrades, North America
Consistent quality and over 10% increase in production with QCS upgrade
