Case Studies

Pulp & Paper

Case Studies:

U.S printing and specialties paper mill gains an ROI of $250,000/yr using DuPulse and Nexus technologies

Opportunity

A mill producing Kraft specialty printing and pressure sensitive grades was experiencing poor press stability during on-the-fly felt washing. The competitive program provided insufficient cleaning and resulted in poor press felt dewatering performance.

As a result of deposit accumulation on the center press roll cover, poor sheet release was experienced. This ultimately led to roll-wrapping on the center roll which resulted in more than $250,000 in production losses and damage to the press & doctor assembly.

The mill was interested in a new felt cleaning program that would improve felt cleaning efficacy, improve press stability while cleaning and provide improved safety around the press section.

All of this was to be achieved at no cost increase from the previous program budget.

The DuBois Solution

After conducting a press section survey, water balance studies, press felt residual sample analytics and felt permeability studies, DuBois implemented new strategies for press felt cleaning and roll treatment.

DuBois implemented their patented DuPulse method of felt cleaning. DuPulse is a unique felt cleaning application method, which utilizes the high pressure, oscillating needle showers to deliver cleaning chemistries on a “pulsed” basis.

The cleaning program was coupled with a DuTrak program monitoring system.

The DuTrak system provides on-line, real-time monitoring of press & Uhle box filtrate characteristics / chemistry, so that the impact of cleaning events can be measured & optimized.

Center roll treatment was provided by patented Nexus technology applied to the roll surface via the doctor lubrication fan showers. The Nexus treatment chemistry provides for both cleaning of the roll and formation of a hydrodynamic film on the roll surface to prevent deposit formation and improve sheet release performance uniformity.

Results and Benefits

The overall program yielded the following impressive results:

• Total productivity gains yielded a net ROI of over $250,000, roughly 120%
• Press water load was reduced by over two million gallons of water per year.
• Press stability was greatly improved and resulted in a 15% reduction in sheet breaks.
• Felt soil loading was reduced by an average of nearly 45%.
• Felt water permeability profiles were greatly improved. Peak-to-peak standard deviation was reduced by 26%.
• Center roll sheet wraps were eliminated.
• Sheet release performance was greatly improved.

Press section safety was improved by reducing chemical concentration in the shower by 88%.