Production of pulp using a gaseous organic agent as heating and reaction-accelerating media

摘要

The invention relates to an improved process to break down lignin macromolecules and liberating cellulose fibers in lignocellulosic material using delignifying reactants with a gaseous organic agent as a heating and reaction-accelerating media. Lignocellulosic material is first impregnated with reactant chemicals, e.g. commonly used agents such as sodium hydroxide and sodium sulfide. Subsequently, the energy required for the delignification reactions is provided through heating with a gaseous organic agent such as methanol or ethanol, condensing and releasing energy to the solid lignocellulosic material. The temperature during the heating step with a gaseous organic agent is higher than the temperature during the impregnation step.

主权项

1. A process for the production of pulp from comminuted lignocellulosic material, comprising first impregnating said comminuted lignocellulosic material in a liquid phase containing fresh reactants comprising an impregnation solution containing at least one compound selected from the group consisting of hydroxides, sulfides, anthroquinones, carbonates, polysulfite ions, sulfites, and acids at a first temperature so as to produce impregnated lignocellulosic material impregnated with an impregnation solution capable of delignification, subsequently removing a majority of the liquid surrounding said impregnated lignocellulosic material, subsequently heating said impregnated lignocellulosic material to a second predetermined reaction temperature using the heat released by the condensation of a gaseous organic agent in contact with said impregnated lignocellulosic material, and subsequently maintaining said second predetermined reaction temperature for a desired reaction time in order to permit said impregnation solution to react with and dissolve the lignin in said lignocellulosic material, said second predetermined reaction temperature being higher than said first temperature.