Stewing process for preparing wood dissolving pulp by natural-color unbleached wood pulp in a modifying way

Abstract

The invention discloses a stewing process for preparing wood dissolving pulp by utilizing natural-color unbleached papermaking-grade wood pulp in a modifying way, overcoming the defect of poor reaction property of products prepared by an alkali refining method. The stewing process conditions of natural-color unbleached wood pulp in a stewing device are as follows: liquor ratio is 1:2.5-7.0; alkali charge includes 10-50% of NaOH and 0.1-50% of Na2S; a temperature increasing condition comprises the following steps of: increasing temperature to 115-130 DEG C for 30-60 minutes, and keeping the temperature for 30-120 minutes; continuously increasing the temperature to 135-150 DEG C for 30-60 minutes, and keeping the temperature for 120-180 minutes; after the temperature is kept, continuously increasing the temperature to 165-175 DEG C, and keeping the temperature for 30-180 minutes; after the temperature is kept, reducing the temperature, and discharging; and stewing to end after the discharging. The wood pulp produced by the stewing process not only has higher content of alpha-celluloses, but also has good reaction property, and is suitable for filament and staple fibers.

Description

technical field

[0001] The present invention relates to the production process and method of wood dissolving pulp (wood pulp) for producing viscose fiber, especially the cooking process for preparing dissolving pulp by modification of natural unbleached wood pulp, and is also suitable for preparing Chemically dissolving pulp and refining pulp for bioproducts. Background technique

[0002] Pulp for viscose fiber requires high α-fiber content, that is, high fiber purity, pre-hydrolysis + alkali method (sulfate method) two-stage cooking or sulfite method two-stage (multi-stage) cooking, adopt the above two Cooking and pulping technology is mainly to remove a large amount of lignin (also known as lignin), hemicellulose (polypentose) and resin and other impurities in the raw material. In particular, the hemicellulose (pentose) in the raw material must be removed under acidic conditions, and the hemicellulose (pentose) must be hydrolyzed under acidic conditions, so that a large a...