Method for extracting xylose from viscoce chemical fiber squeezed alkali liquor

Abstract

The invention relates to a method for extracting xylose from viscoce chemical fiber squeezed alkali liquor. According to the technical scheme, the method comprises the following steps: pre-filtering to obtain pre-concentrated liquor; filtering the pre-concentrated liquor through a nanofiltration membrane to obtain concentrated liquor; adding hydrochloric acid to the concentrated liquor to obtain hydrolysate; adding hydrolysate to NaOH until being neutral; decolorizing; regulating the concentration of NaCl; cooling at constant speed until reaching room temperature; enabling glucose in hydrolysate to cocrystallize with NaCl to remove glucose; treating filtrate through ion exchange columns to obtain purified liquor; crystallizing and purifying the purified liquor for the second time to obtain coarse xylose; refining the coarse xylose to obtain final xylose. With the adoption of the method, the resource is saved, the economic benefit is brought to enterprises, and the environment is protected.

Description

technical field [0001] The invention belongs to the technical field of functional sugar preparation, and in particular relates to a method for extracting xylose from pressed lye produced from chemical fiber viscose. Background technique [0002] Viscose chemical fiber is made of pulp made of cotton linters, wood pulp and pulp made of other fibers. In the production process, it is first necessary to add lye (usually NaOH solution) for impregnation, and then squeeze the impregnation solution, the obtained alkali cellulose is further added with carbon disulfide and yellowed into viscose, the viscose passes through a high-pressure spinneret to form fiber filaments, and the fiber filaments are cut and dried to form viscose instead of cotton fibers fiber. The compressed lye is recycled for impregnating pulp. [0003] However, the raw material pulp for viscose fiber production also contains part of xylose and glucose polymer hemicellulose when it is made into pulp. When viscose f...

AI Technical Summary

Problems solved by technology

[0003] However, the raw material pulp for viscose fiber production also contains part of xylose and glucose polymer hemicellulose when it is made into pulp. When viscose fiber is produced, the hemicellulose will be dissolved in the dipping lye. With the continuous increase of hemifiber content in alkali, the difficulty of pressing alkali cellulose is also gradually increasing, the yellowing reaction performance and viscose filtration performance are gradually declining, and the consumption of carbon disulfide is correspondingly increased, which affects the production stability and product quality of the impregnation alkali process. Inconvenience to production

Therefore, when the concentration of hemicellulose in the squeezed lye reaches a certain concentration, the enterprise will discard this part of the squeezed lye, which brings great difficulties to the subsequent sewage treatment on the one hand, and the squeezed lye also contains Some lye and hemicellulose are beneficial ingredients, and discarding them in vain also causes a waste of resources