Rasool et al. _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ The stock preparation is prominent subsystem in paper manufacturing plant. It comprises using five subsystems by utilizing various redundancy strategies. The configuration of subsystems shown in Figure 1. The detailed description of subsystems is as follows: Subsystem A: This subsystem consists of a Storage Tank. It is used to hold the pulp liquids, compressed gases or mediums used for short- or long-term storage of heat or cold. The failure of this system can lead to a failure of the entire system. Subsystem B: This subsystem consists of a Repulping or Slushing. This system helps to break down the dried primary fiber pulp or recovered paper into individual’s fibers. After that the remaining flakes have to be broken down in next deflaking machinery. The failure of this subsystem may cause the complete failure of the system. Subsystem C: This subsystem consists of a deflacking process and helps to break down small pieces (flakes) break up paper or pulp sheets into individual fibers.it helps to avoid paper quality problems, to save fiber raw material and verify enhanced operating conditions for the advancing machines in the process e.g., screening or cleaning. The failure of this system also causes the complete failure of the system. Subsystem D: This subsystem consists of a Storage and Mixing Chest. The pulp is pumped to the storage chests or mixing chests. These chests perform as a buffer between the stock preparation and the actual paper machine. In the mixing chests, prepared stocks are mixed in proportions. Failure of this system causes the complete failure of the system. Subsystem E: This consists of a paper machine. In this system, the final product of storage and mixing chest is send to the paper machine for producing a specific quality of paper.
Figure 1 . Flow diagram of a Stock Preparation Unit of paper plant.
_____________________________________________________________________________________________ 4 Braz. J. Biom. ǡǤ 43 ǡǦͶ͵ʹǡʹͲʹͷǤ
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