Analysis of fiberline log sheet survey - Production rate variation seems upsets brightness most

In 1996, the CPPA Bleaching Committee asked all Canadian bleached kraft mil ls to send log sheets for their best three consecutive days of the previous 30 days of operation. In total, data for 21 bleach plants were received wi th most including digester, O-2 delignification and bleach plant log sheets . This paper summarizes the key operating parameters with a particular focus on correlations leading to brightness variability. Production rate variatio ns appear to cause the biggest upsets. By basing the analysis of each mill on the unitless coefficient of variability, comparison with the reported pe rformance can be done by any reader so interested. Also examined is such information as testing frequency and type, items logg ed or not logged and frequency of record. This survey provides a fascinating glimpse into what the mills consider imp ortant enough to record and allows a uniform evaluation of what the best mi lls achieve as well as how wide is the spread. No attempt was made to compa re chemical consumptions or extract other information that depends on bleac hing objectives, sequence, equipment or furnish.