Chemical fiber slurry cellulose alkali squeezing liquid treatment and recovery technology

A technology for processing cellulose, which is applied in the field of processing and recycling process of chemical pulp cellulose alkali squeeze liquid, can solve the problems of poor stability in the processing process and the inability to meet the concentration of lye in the dipping process, etc., and achieve high value-added recycling and simplification. Effect of pretreatment process and system stability

Inactive Publication Date: 2016-04-27
SHANGHAI KAIXIN ISOLATION TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At this time, although the alkali is purified, the concentration of the obtained alkali is greatly diluted, which cannot meet the concentration of alkali solution required by the impregnation process, and cannot be directly reused in the process. It must be concentrated until the concentration required for impregnation can be reused.
At the same time, due to the limitations of the membrane material and membrane element structure in the original process, the stability of the treatment process is poor, and perfect pretreatment is required.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Alkali squeeze liquid is 100 cubic meters, the concentration of sodium hydroxide in the feed is 250g / L, and the content of hemicellulose is 25g / L. Enter the first-stage membrane separation system at a temperature of 50 degrees Celsius, and the cut-off pore diameter of the membrane is 5nm. Operate at a pressure of 2MPa. When concentrated to a hemicellulose content of 80g / L, enter the secondary membrane system and add water for dialysis. The cut-off pore size of the secondary membrane is 5nm. The membrane filtrate of the primary membrane separation system and the secondary membrane separation system is placed in the filtrate tank for standby. Total filtrate hemicellulose content 7g / L. Back to the impregnation process.

Embodiment 2

[0035] The membrane concentrate of the alkali recovery system is 5 cubic meters, of which the hemicellulose content is 300g / L, and the sodium hydroxide concentration is 60g / L. Add 30% sulfuric acid solution equimolar with sodium hydroxide to the container where the concentrated solution is placed, and stir while adding. Hemicellulose is precipitated. Let stand for more than 2 hours. Enter the three-stage membrane separation system with a cut-off aperture of 50nm for separation. At a pressure of 0.6 MPa, the membrane surface flow velocity was maintained at 5 m / s. Concentrate to a volume of 2-3 cubic meters first, then add water for dialysis, and add 10-15 cubic meters of water. A hemicellulose concentrate that can be directly recovered is obtained.

Embodiment 3

[0037]Alkali squeeze liquid is 100 cubic meters, the concentration of sodium hydroxide in the feed is 200g / L, and the content of hemicellulose is 20g / L. Enter the primary membrane separation system at a temperature of 50 degrees Celsius and operate at a pressure of 0.4 MPa. When concentrated to a hemicellulose content of 82g / L, enter the secondary membrane system and add water for dialysis. The membrane filtrate of the first-level membrane separation system and the second-level membrane separation system is placed in the filtrate tank for standby.

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Abstract

The invention discloses a chemical fiber slurry cellulose alkali squeezing liquid treatment and recovery technology. The technology mainly comprises first-grade film separation, second-grade film separation, hemicellulose precipitation, third-grade film separation and hemicellulose recovery. The invention provides a novel technology for recovering hemicellulose and alkali from an alkali squeezing liquid. Compared with the prior art utilizing a nanofiltration system for recovering alkali, the treatment and recovery technology provided by the invention utilizes an inorganic material membrane to recover alkali, has simple pretreatment processes and has system operation stability, a long cleaning period and a high alkali recovery rate.

Description

technical field [0001] The invention relates to the treatment of three wastes, in particular to a treatment and recovery process of chemical pulp cellulose alkali squeeze liquid. Background technique [0002] In the production process of viscose fiber (rayon) using chemical fiber pulp (wood pulp or cotton pulp, straw pulp, bamboo pulp, reed pulp and other plant cellulose) as raw materials, the cellulose alkali treatment process is the key to the production of viscose fiber. first step. Usually the manufacture of fiber products requires that the purity of α-cellulose used as raw material reaches more than 92% (not less than 90%). Since the raw material still contains more hemicellulose, it is necessary to dissolve the hemicellulose with alkaline solution in the impregnation process to obtain high-strength cellulose. The high concentration of hemicellulose will have extremely adverse effects on the production process of viscose fiber and the quality of finished products. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C11/04
Inventor 申雅维张芸
Owner SHANGHAI KAIXIN ISOLATION TECH CO LTD
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