Optimization of an Organosolv Process for White Birch, 1992 Solvent Pulping Symposium Proceedings

Given the application of more severe environmental legislation in the pulp and paper industry as well, as the depleting reserves of available softwood, one is forced to find alternate pulping methods for the production of chemical pulps. In the province of Quebec there are important quantities of white birch (33% of commercially available hardwood) which could be used more profusely in the making of chemical pulp. Furthermore, it is known that hardwoods respond well to an organosolv process. As a result, pulping of white birch was performed on a laboratory scale using a blend of caustic soda and denatured ethanol as the solvent medium. A chemical pulp was obtained in a relatively short time using this process. The resulting pulp had excellent physical properties due to enhanced delignification which is attributed to the increased penetration of caustic soda within the chips in the presence of alcohol. By varying temperature, alcohol concentration, and alkali concentration, according to a factorial design, an attempt was made to optimize the cooking conditions for white birch. The physical properties for each condition are discussed. The pulp obtained from the recommended conditions is then compared to a kraft pulp on a basis of identical active alkali.