Implementation of a 4 Stage Screening System and ECF Conversion at Gulf States Paper Corporation, 2000 Pulping / Process & Product Quality Conference Proceedings

J. Pearson, A. Harrington--Gulf States Paper Corporation, Demopolis Mill, is a bleached Kraft mill in western Alabama. The mill has been utilizing Lo-Solidsâ cooking technology since 1994 and has had the ability to run ECF when desired. In 1997 the design began for the ECF conversion and it was determined that the current state of screen technology at the mill was not sufficient to support the conversion to ECF bleaching on a full time basis.

A new four-stage screening system and medium consistency Do stage was installed to meet the following objectives.

1. Reduce the amount of particulate dirt sent to the bleach plant

2. Allow the bleach plant to operate at lower chemical application rates.

3. Improve pulp quality and reduce the amount of offgrade pulp.

4. Increase brightness ceiling and brightness response.

5. Reduce fiber loss in the screening system.

The project was an overwhelming success and all operating targets were reached and/or exceeded. Total ECF bleaching chemical cost was reduced by 30% and the improvements in quality have reduced offgrade product dramatically.