Chip retention disturbances at the continuous digester: One alternative for performance optimization

摘要

One of the main problems of continuous digester operation is the adequate control of liquor and chip level. This is the main issue in almost of all plants, concerning production and uniformity quality process . In this work, the interaction of different cooking process variables of industrial continuous digester is analyzed , and its correlation between chip retention disturbances and chip column movement. Using industrial process data an excel applicative was done , applying a correlation test of the following variables : Temperature discharge, extraction flow, blow line flow, chip level, partial and total liquor level, screen pressure drop, chip density drop, amperage discharge blow and circulations temperature. As final equation by these different correlations, is generated a graph line that indicates the 'Digester Criticity Index". This Index gives an online estimative number, of how big is the operational stability and which one is the main point the operator must observe or correct. The applicative is formulated with the aid of the current process measurements, through the Process Information Management System and Excel resources (with on line feeding), allowing the operators to take corrective actions in advance, looking for to minimize production losses and quality problems. The applicative was adopted successfully in the two production lines from CENIBRA Mill (960,000 admt/year), reducing approximately 70% of production losses of Hanging problem.