Madison Paper remains competitive with program of technology renewal

Pulp & Paper, May 1994 by Yeager, Bob

Flexible reporting and expansion. A DCS Report Station is currently being developed, whereby routine production reports can be quickly generate for managers in the mill. Reports that typically took two hours to develop will now be done in minutes. "We're no longer limited by the technology," says Herb Jordan, technical and stock prep manager. "We are only limited by our ability to envision the need and create the application." The DCS will also soon be applied to Madison's sodium hydrosulfite bleaching operation.

PROJECT RESULTS. To date, Project 4200 has shown good results. The paper machine now routinely runs between 3,600 and 3,800 fpm, increasing mill production by 10%. Production speeds of 4,000 fpm have been achieved, though 3,800 fpm taxes the capacity of the groundwood mill.

End product quality has improved well. Moisture profile variation out o the dryers has been reduced from 3 or 4% to less than 1% peak-to-peak (a 60 % reduction).

Dye upsets have been reduced to zero from a previous of six or seven per month (each causing the loss of two paper reels). Dye fluctuations within reels have been cut dramatically.

Sharp boiler swings have been eliminated following a paper break. Quicker threading has reduced off-spec paper by 50%. Steam savings have also been substantial. "We now have the tools to more meaningfully measure and understand process variation," says Pineo. "Because of this, we can expect ongoing quality and productivity improvements in the future."

LOOKING AHEAD. As a follow-up to Project 4200, Madison will undertake some major updates in June 1994. The scanners will be replaced with Valmet's new "Ultra Scanner," a smart scanning platform with an Ethernet connection to the DCS. In addition, all existing on-machine gauges will be replaced by faster and more accurate versions. These will include basis weight, moisture, ash, opacity, and color. All scanner and sensor controls will be implemented in the DCS.

"The new scanners and sensors should eliminate scanner deflection and give us 1-cm streak resolution," says Pineo. "In addition, the integration of gauges, scanners, and DCS will eliminate gateways and linkages, reduce potential points of failure, and reduce spare pans inventory at the mill."

Sixty-two of Valmet's smart headbox actuators will be installed on the slice lip for improved CD basis weight control. The digital actuator system will link to the DCS via a two-wire, RS-422 serial linkage. A DCS intelligent data stream will order the actuators to new CD positions and receive individual position feedback from each actuator. All CD control algorithms will be implemented in the DCS.

"As we run faster and faster machine speeds, maintaining an excellent profile becomes more of a challenge," says Troy. "The improved gauging and slice lip control will help considerably."

A new Valmet OptiReel will replace the existing reel and associated controls to maintain constant tension throughout the reel at the faster machine speeds and minimize waste at reel turn-up. All OptiReel logic will be implemented in the DCS platform.