Biopulping: a Less Polluting Alternative to CTMP

At present, pulp is produced from wood either by chemical delignification, mechanical separation of the fibers, or combinations of chemical and mechanical methods. Mechanical pulping methods are being used increasingly because they give much higher yields (>90%) than do chemical methods (40-50%) and require less capital investment. The main disadvantages of mechanical pulping are the high energy requirement, the low strength and the low brightness stability of mechanical pulps (Table 3.1). Addition of chemical pulp is often required to produce papers with adequate strength.