Inline pitch analysis

Motivation

Pitch particles in pulp suspension cause both runnability issues and defects in the final paper sheet. Pitch control chemicals are used to disperse and break down large pitch particles to minimize their effects. To optimize the chemical dosage, real-time measurement data of the pitch content is needed.

Implementation

A Pixact Stock Monitoring (PSM) system is installed on a bypass line to acquire images of the flowing pulp suspension in the paper machine’s short circulation (headbox consistency). The PSM system detects impurities in the pulp suspension and classifies particles with a yellow tint as pitch, omitting all other impurities from the statistics. Laboratory analysis of pitch content is used to verify the results.

Benefits

The results show that the pitch content varies significantly with the raw material. Real-time analysis of pitch content enables the optimization of pitch control chemicals.