Allan Johansson

Organosolv pulping — methods and pulp properties

Abstract Potential benefits of using organic solvents for the delignification of lignocellulosic materials are discussed. Main characteristics of organosolv pulping methods published in the literature are presented and softwood pulp yields and strengths are compared with corresponding values of Kraft and sulphite pulps. Yields of organosolv softwood pulps can be higher than yields of conventional pulps at equal kappa number. Tensile and tear strengths of softwood organosolv pulps fall between the corresponding values of Kraft and sulphite pulps. The published data shows that organosolv pulping methods have considerable potential in terms of delignification selectivity and papermaking quality. It is postulated that a more systematic research to reveal the relationships between the physical and chemical characteristics of organosolv fibres and pulp quality is needed so that the pulping methods can be modified and the full potential of organosolv processes utilized.

By-product recovery and valorisation in the kraft industry: A review of current trends in the recovery and use of turpentine and tall oil derivatives

Abstract Recent trends in the field of turpentine and tall oil recovery and valorisation in the kraft industry are reviewed. References from 1972 onwards are included. Review articles are cited for those interested in older references.

A new chemical recovery system for the Kraft process. Results from continuous bench-scale operations

Abstract The possibility of recovering organic material from Kraft spent liquor using treatment with CO under pressure has been investigated. This process results in formation of a hydrophobic oil from the organic constituent, while the inorganic cooking chemicals remain in the aqueous layer.