Production of Pulp Using a Gaseous Organic Agent as Heating and Reaction-Accelerating Media

Abstract

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.

Dependencies are inferred from the claim text.