Reliability and Maintenance

An Effective Solution for Dryer Section Deposition

TAKANORI TSUJI

In recycled papermaking, the use of recycled furnish has led to increased deposits on paper machines. Deposits can cause sheet breaks, limit machine speed, and increase machine cleaning frequency. Consequently, more effective and complete solutions are required.

Dryer Section Passivation (DSP) can provide a solution. DSP technology effectively prevents deposition on dryer cans, fabrics, fabric rolls, and calender rolls, thereby solving problems such as sheet breaks, limited machine speed, cleaning frequency, and increased steam consumption.

a figure close up view of the spraying equipment
Fig. 1: Close-up view of the spraying equipment.

DSP application is a complex technology consisting of chemical products, spray equipment, and application methods (Fig. 1). The technology was invented 35 years ago by Maintech Corp., a global provider specializing in dryer section improvement. The company has continued to develop the technology and today is the largest DSP supplier in the world, with more than 1,000 applications on more than 326 paper machines.

DSP technology follows several critical steps:

  1. DSP transfers to subsequent dryer cans: A custom-designed chemical composition enables the chemical effect to transfer from the sprayed surface to subsequent cylinders via the sheet, despite having only one application point.
  2. Air curtain with high spray efficiency: A patented nozzle uses an air curtain that enables the spray to cut through paper machine windage and deliver the chemical to the cylinder/fabric surface for passivation (Fig. 2). The air curtain technology improves spraying efficiency, and it effectively prevents deposits with a small chemical dose.
  3. Stable operation of spray equipment: The spray equipment is specifically designed to withstand heat and moisture, even in high temperature hoods. Maintech provides stable operation of spray equipment with periodic free maintenance and overhauls. Of more than 1,000 applications currently operating around the world, there were only seven cases of unexpected failure in 2023 (less than 1 percent of installed operations).

When these steps are followed, mills installing DSP technology have reported several specific benefits, including:

  • Less frequent dryer section sheet breaks
  • Increased machine speed (for higher production)
  • Reduced cleaning time and frequency
  • Reduced operator’s manual cleaning
  • Improved safety
  • Reduced steam consumption (for lower energy costs)
a figure air curtain technology improves spraying efficiency
Fig. 2: Air curtain technology improves spraying efficiency.

CASE STUDY: GREIF PACKAGING

These benefits are demonstrated in a case study of DSP implementation for a customer with problems caused by deposits from using recycle furnish: Greif Packaging in Massillon, OH. The mill chose DSP for its PM2, which produces 380 tpd of corrugated medium with a machine width of 150 inches.

“Installation of Maintech DSP was one of the best projects I have ever worked on,” says Rod Haumard, electrical supervisor at the mill. “Documentation was fantastic, with clear instructions on wiring and other aspects of installation. Great engineering—which made installation very easy.”

The mill was experiencing several problems caused by deposits on the dryer section, including frequent sheet breaks, excessive cleaning time, and fire hazards due to excessive dust.

Following a comprehensive dryer section audit, the mill chose to install two DSP applications (see Fig. 3). Figure 4 provides comparisons showing that each treated surface drastically improved after using DSP. In addition, sheet breaks were reduced, and frequent cleaning of the doctor blades was no longer needed.

a figure diagram shows the location of the two dsp systems
Fig. 3: Diagram shows the location of the two DSP systems installed on PM2.

The project was successful right off the bat, according to Creighton Fike, superintendent. “Working with the whole Maintech group has been an absolute pleasure. Everyone has been very professional since our first meeting. As far as the equipment is concerned it has been very good at helping keep our dryer, felts, and felt rolls cleaner. Another big bonus has been the runnability of the equipment: It sets there and runs great,” Fike says.

PM2 operators reported these key results from the DSP system installation:

  • The systems reduced first dryer doctor cleanings from multiple cleanings per shift to NO cleanings required—a huge time saver for machine crews.
  • Reduced break frequency by two breaks per week resulting from dryer section deposition.
  • Reduced overall machine linting, mitigating the fire hazard.

“We love this system here at Greif Massillon,” says Machine Superintendent Wayne Steele. “The ‘MistRunner’ DSP system has proven from the start to reduce the way the felts build up with sticky residue. Our dryer felts used to get so compacted, with big clumps of stickies in our fabrics. Now with the MistRunner chemical, it seems to turn the heavy sticky residue into a softer, powdery residue that our pressure cleaner takes away easily.

a figure various surfaces shown before and after installation
Fig. 4: Various surfaces shown before and after installation of DSP technology at the Greif mill.

“The DSP system also keeps our felt rolls and dryer cans cleaner from building up dust and other debris that we would have to carefully try to scrape off the doctor blades,” continues Steele. “The unit just runs and hardly ever needs to be dealt with, either electrically or mechanically.”

For Greif, DSP was the best solution for problems caused by deposition on the dryer section. After conducting a dryer section audit, Maintech works closely with customers to prevent deposition and contribute to improvements in runnability, reduced manual cleaning, and improved operational safety.

Takanori Tsuji is president and CEO of Maintech USA Corporation. With US offices in Atlanta and Chicago, Maintech provides chemical products, spray equipment, maintenance, and technical services. Contact Robert Deshaies at [email protected] or 224-520-8171 to learn more, or visit maintech-papertech.com/en/.

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