Drying Section Deposits: Origin Identification and Influence of the Recycling Processess: Deinking and Packaging Line Comparison, 2005 Engineering, Pulping, & Environmental Conference

Mills producing papers (particularly packaging papers) made from recycled fibres very often face an important formation of organic deposits on various equipment of the paper machine (formation wire, presses, drying section cylinders and wires…). Moreover, many problems are connected to these deposit formations: breaks, paper defects (presence of spots, holes…), and reduction of the drying section efficiency due to the felts clogging... As a consequence, these phenomena cause many shutdowns of the machine for the cleaning of the clogged equipment.

These deposits in the drying section mainly originate from contaminants present in the fibrous suspension, which were not eliminated by the decontamination steps performed during the pulp preparation. Analysis carried out on deposits collected in paper machines, show that they mainly consist of polymers, which are used, in the formulation of converting additives and particularly adhesives. Thus, the polyvinyl and polyacrylic esters are very often found as main components of the deposits in the drying section.