Chain of Custody Yield Factor Reconciliation across Multi-Site Kraft Paper Mill Networks
Multi-site kraft paper networks reconcile physical process yield losses against certified volume balances through standardized mill conversion factors.
Broke Yield Loss
Fiber Recovery
Internal recycling circuits process off-specification paper and web trimmings to return usable cellulose to the stock preparation system. Broke yield loss quantifies the percentage of solid material permanently destroyed or discarded during the repulping, screening, and cleaning of wet or dry broke. High-shear pulping disintegrates dry web fragments, but fines washed through white water systems or rejected by centrifugal cleaners represent unrecoverable mass.
Standard mill controls track this loss to evaluate re-boarding efficiency and chemical additive retention.
Reboarding Degradation
Mechanical action in broke pulpers breaks down hydrated fiber walls and generates secondary fines that escape stock containment loops. Starch coatings and surface sizing flakes loosen during re-slurring, flowing into effluent clarification systems rather than redepositing on the wire. Wet strength additives complicate deflaking operations, forcing higher energy inputs that shorten fiber length and increase total reject mass at the screening station.
Unrecovered fiber flakes accumulate in primary sludge pits, reducing total mill fiber conversion efficiency. Lower grade stock formulations sustain higher percentage mass reductions when handling heavily coated board trimmings.
Mill Efficiency
Material balance calculations reconcile couch pit slurry volumes against finished reel weight to establish precise broke accounts. Broke yield loss directly increases raw virgin pulp demand and elevates water treatment loading per ton of saleable paper output. Continuous monitoring allows process engineers to optimize deflaker plate gaps and white water flotation savealls.
Minimal fiber degradation during repulping preserves physical strength properties on paper machines.