Systems for Broke Treatment

Broke is an important stock source and occurs on a continuous basis as trims from the wire as wet broke and from the winders as dry broke. It can also occasionally occur as reel slab-offs, in the finishing room or during breaks in the paper machine or coating equipment. Usually all broke is fed back to the process in the approach flow system. Broke treatment starts with slushing in different pulpers. These pulpers are installed under the machine and dimensioned according to the 

In secondary fiber preparation, peripheral systems are very important for the runn-ability of the whole plant as well as for cost minimization and environmental issues. Peripheral plant components are the reject system, sludge treatment and water handling (see Fig. 4.56-4.60). Coarse rejects from the pulping section, heavy particle separation and hole screening are dewatered to a dry content of approximately 60%. If thermal treatment is involved for these rejects, metal components have to be removed and the particle size adapted to the burning process by means of shredding. 

Fine rejects and sludges from the flotation stages and the DAFs are also drained to approximately 60 % dry content and either sent to energy recovery or used in the concrete or brick industry [3]. Water handling is another key element as it affects -besides costs and environmental issues - various quality parameters of the finished product such as brightness, cleanliness or odor (see Chapters 5 and 10). 

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