Papermaking energy requirements

Traditionally, the aim of separating the wood components has been associated with papermaking, in which delignification isolates the cellulose fibres. In this context, the dissolved lignins have been utilized as fuel, which provides not only the energy required by the process, but also a convenient way of recovering its inorganic catalysts. 

Both pulping and papermaking are energy intensive processes. Mechanical pulp production requires large amounts of eleetrieal energy. Chemical pulping processes on the other hand use principally thermal energy and ehemicals. Semichemical pulps are intermediate in their requirements. 

All these components have to be adequately prepared for optimum use in the papermaking process steps. The additives may be delivered ready for use or may have to be finally prepared according to the requirements in the mill. Fiber stock preparation includes several unit operations depending on the furnish and the purpose. Stock preparation of virgin fiber pulp needs less machinery and energy than the preparation of recovered paper which, however, is the cheaper raw material. Fiber stock preparation ends at the paper machine chest. Here stock of high consistency is preferred to minimize carry-over of chemicals and contaminants. 

The various requirements for the production of paper are not met everywhere. For instance, suitable raw materials must be available, including water, energy, and trained personnel. Furthermore, the construction of paper mills requires a very high investment, and a sufficiently large market and a favorable location are both essential prerequisites for economic papermaking. For these reasons, the modern paper industry is based mainly in the coniferous forest zone of the Northern Hemisphere, with centers in Europe, North America, and in Japan. 

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