Pulping operations beating

Pure cellulose makes inferior paper, because cellulose fibers suffer appreciable physical degradation during the pulp beating operation. A certain amount of hemicellulose, especially the uronic acid subfraction, improves quality (Whistler and Smart, 1953). 

In order to enhance the bonding capability of the fibers, it is necessary to mechanically beat or refine them in equipment such as beaters, jordans, or disc refiners. This treatment of the pulp slurry at about 3-6 percent consistency is done by passing the pulp between the two rotating surfaces of the refiner. These surfaces contain metal bars and operate at very close clearances. As the fibers pass between the bars, they are made more flexible, and a larger surface for bonding is developed by the mechanical action. 

The pulp to be treated with cellulolytic enzymes should first be screened in a laboratory flat screen to remove any shives. The screened pulp is beaten either in a laboratory Hollander beater (TAPPI Standard Method T 200 os-70) or in a PFI mill (TAPPI Standard Method T 248cm-85), depending on the amount of pulp to be treated, to a final Canadian Standard Freeness of 200-300 ml. The beating operation helps convert shives into fibers and improves the digestibility of the pulp towards cellulolytic enzymes. The pulp is dewatered to a consistency of approximately 25% and stored in a polyethylene bag after fluffing. 

The first operation in the paper mill involves stock preparation the slushing of baled pulp, the refining or beating of chemical pulps, the blending of pulp stocks and additives prior to forming paper. 

Stock preparation in a paper mill includes all intermediate operations between preparation of the pulp and the final papermaking process. It can be subdivided into (1) preparation of the furnish and (2) beating or refining. Furnish is the name for the water slurry of... 

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