Paper stock/ cellulose has characteristics that make it very difficult to pump. These are: fiber length, freeness (tendency to dewater), degree of agitation,entrained air, and consistency of the stock. Many mills have changed their pumps from centrifugal to progressive cavity since these pumps exhibit low shear rates, and require less suction head.
Cellulose fibers are fibers made with ether or esters of cellulose, which can be obtained from the bark, wood or leaves of plants, or from a plant-based material. Besides cellulose, these fibers are compound of hemicellulose and lignin, and different percentages of these components are responsible for different mechanical properties observed.
The main applications of cellulose fibers are in textile industry, as chemical filter, and fiber-reinforcement composite, due to their similar properties to engineered fibers, being another option for biocomposites and polymer composites.