Chemical variations:Influence on runnability of paper machines and separate coating lines

The results of a study undertaken on a paper machine (PM) with a separate coating machine (PCM) located in Finland to understand the link between runnability of paper and coating machines and chemical variations in the paper machine's wet-end were presented. The biocide program at the machine was based on weak oxidizers, which were used to treat the low consistency flows. The data for the analysis performed in this study was mainly taken from the mill's database. The efficiency of the system was based on the usage of stabilized halogens. The chemical variations causing poor PCM runnability are a combination of three different factors that include PM breaks, broke management, and temperature control. A break or planned stoppage at the paper machine always disturbs chemistry of the machine. Chemical flows are disturbed and the broke cycles are burdened. The PM break further increases the broke volumes, causes extended delays in the broke towers and enables increased microbial growth in the broke towers