Method for preparing xylose from dissolving pulp precooking waste liquid

Abstract

The invention discloses a method for preparing xylose by utilizing dissolving pulp pre-cooking waste liquid. The method includes the following steps: (1) under the condition of pH value of 9-11, the pre-cooking waste liquid of dissolving pulp is filtered, and the collected filtrate is material A; the solid content of material A is 5%-7%; (2) The material A is treated with an ultrafiltration membrane to obtain a concentrate and a filtrate, and the filtrate is collected as material E, wherein the solid content of the concentrated solution is 10% to 15%, and the temperature of the ultrafiltration membrane treatment is at least 50 ° C; (3) Material E Mixed reaction with an acidic substance to obtain a crude material containing xylose; wherein, in step (3), the molar amount of hydrogen ions in the acidic substance and the volume ratio of material E are 0.5~1mol / L, and the temperature of the mixed reaction is 90~10 mol / L. 110°C. The xylose is extracted by the membrane method combined with the simple process of ethanol precipitation, and the added value of the pre-cooking waste liquid of the dissolving pulp is improved. The treatment process greatly reduces waste water discharge and improves the utilization rate of pre-cooking waste liquid of dissolving pulp.

Description

technical field [0001] The invention relates to a method for preparing xylose by utilizing dissolving pulp precooking waste liquid. Background technique [0002] Dissolving pulp pulping is one of the emerging pulping methods in recent years. It adds a pre-cooking process on the basis of the original kraft pulping process to further remove hemicellulose and lignin in the raw materials to obtain higher Pure cellulose is used to produce viscose fiber. During the precooking process, under the action of high temperature of steam or water, a large amount of hemicellulose sugar and more lignin are removed, the solid content of the feed liquid is low, and the calorific value is low. Combustion needs to consume a lot of steam for concentration, and the calorific value of the feed liquid is low, so it is not easy to burn, which will increase the load of the alkali furnace. deal with. The hemicellulose sugars in the effluent were not better utilized. [0003] In the prior art, xylos...

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art that the dissolving pulp pre-cooking waste liquid is treated by burning, which not only pollutes the environment, but also reduces the utilization rate of the dissolving pulp pre-cooking waste liquid, and provides a method of using dissolving pulp pre-cooking waste liquid. Method for preparing xylose from cooking waste liquid

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