Date of Award

4-1982

Degree Name

Bachelor of Science

Department

Paper Science and Engineering

Abstract

Press section water cannot be reused on a fine papermachine due solely to the fact that fibrous contaminants, specifically felt fibers that are removed by the felt cleaning system, cause an inordinate amount of trailing blade coater scratches and other defects in the final product. In this study, the feasability was examined of using a Ronnigen-Petter CycloSpray high solids filter to remove felt and cellulose fibers from press water.

By maintaining a constant fiber content of 0.4 lbs./1000 gallons and increasing the filler loading from 20 lbs./1000 gallons to 40 lbs./1000 gallons, the effect of increasing filler loading on fiber removal was studied. Major trends observed were as follows:

1. Accepts solids flow rate increased with increasing inlet solids flow rate (slope = 0.68)

2. Rejects solids flow rate was essentially constant with increasing inlet solids (slope = 0.04)

3. Accepts filler flow rate increased with increasing inlet filler flow rate (slope = 0.69)

4. Rejects filler flow rate was essentially constant with increasing inlet filler flow rate (slope = 0.03).

These trend observations lead to the conclusion that as filler loading increased, fiber removal from simulated press water was accomplished, by the Ronnigen-Petter CycloSpray high solids filter.

To further accentuate these results, the felt fiber inlet content was increased, which resulted in an increase in reject solids by almost the same amount and a decreased reject ash content.

Screen size best suited for fiber removal from press water was found to be 250 mesh stainless steel.

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