High-yield pulp of hybrid poplar wood by integrating steam explosion process as a pre-stage to alkali pulping

摘要

High temperature and pressure treatment of chemically impregnated wood chips has been investigated as a pre-treatment prior to kraft and soda pulping to achieve higher yield. The experimental study was carried out in four phases---the pre-treatment of raw material; physical analysis of pre-treated wood; micro-pulping, to identify the effect of process variables on delignification and pulp yield; and small scale pulping to confirm the trend from micro-pulping and evaluate the pulp properties.;Small uniform fragments were obtained upon pre-treatment and the wood architecture was disrupted due to the collapse of a large number of vessel elements present. Lignin structure appeared to break down to a certain extent. Mathematical models, based on micro-pulping experiments, are proposed to predict the dependency of yield and lignin removal on process variables. Pretreatment of raw material is found to have advantages over untreated material through improved pulp yield and reduced chemical and energy requirements.