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Recovery method of spinning waste liquor by means of concentrating

A recycling method and waste liquid technology, applied in the field of spinning, can solve the problems of unfavorable cost control and industrial application, low recovery rate of NMMO, waste of resources, etc., and achieve the effect of small footprint, small investment and water saving

Inactive Publication Date: 2011-08-31
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Both methods need to use a large amount of water vapor, and the recovery rate of NMMO is not high, which is not conducive to cost control and industrial application
In addition, the anion and cation resins in the anion and cation resin exchange / decompression evaporation method need to be regenerated frequently, which will also cause environmental pollution and waste of resources

Method used

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  • Recovery method of spinning waste liquor by means of concentrating
  • Recovery method of spinning waste liquor by means of concentrating

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] a. Pretreatment: Under the water temperature condition of 21° C., pressurize the NMMO low-concentration solution with a mass percent concentration of 1.04% to a pressure of 0.2 MPa. Send it to a 2-micron precision filter for precise pretreatment, and the precision filter is filled with polypropylene fine filter cotton;

[0020] b. Reverse osmosis concentration: Send the filtrate in step a. under the pressure of 2.8MPa into the reverse osmosis membrane module for reverse osmosis concentration treatment. The operating pressure of the reverse osmosis membrane module is 2.8MPa; The reverse osmosis membrane in the module is a roll membrane, and the membrane material is polyamide material;

[0021] c. post-processing: the concentrated water outlet in the b. step obtains a mass percent concentration of 8.6% NMMO high-concentration solution, and the high-concentration NMMO solution is sent to a vacuum distillation tower for further concentrated treatment; the pure water outlet ...

Embodiment 2

[0023] a. Pretreatment: Under the water temperature of 22°C, pressurize the NMMO low-concentration solution with a mass percentage concentration of 1.1% to a pressure of 0.2MPa, and then send it into a 2-micron precision filter for precise pretreatment. Polypropylene fine filter cotton.

[0024] b. Reverse osmosis concentration: Send the filtrate in step a. under 2.5MPa pressure into the reverse osmosis membrane module for reverse osmosis concentration treatment. The operating pressure of the reverse osmosis membrane module is 2.5MPa; The reverse osmosis membrane in the module is a roll membrane, and the membrane material is polyamide material.

[0025] c. Post-processing: the concentrated water outlet in the b. step obtains a high-concentration solution of NMMO with a mass percent concentration of 8.2%, and the high-concentration NMMO solution is sent to a vacuum distillation tower for further concentrated treatment; the pure water outlet in the b. step Obtain pure water wit...

Embodiment 3

[0027] a. Pretreatment: Under the water temperature of 25°C, pressurize the NMMO low-concentration solution with a mass percentage concentration of 1.06% to a pressure of 0.2MPa, and then send it into a 2-micron precision filter for precise pretreatment, and put it into the precision filter Polypropylene fine filter cotton.

[0028] b. Reverse osmosis concentration: Send the filtrate in step a. under 2.9MPa pressure into the reverse osmosis membrane module for reverse osmosis concentration treatment. The operating pressure of the reverse osmosis membrane module is 2.5MPa; The reverse osmosis membrane in the module is a roll membrane, and the membrane material is polyamide material.

[0029] c. post-processing: the concentrated water outlet in the b. step obtains a high-concentration solution of NMMO with a mass percent concentration of 8.3%, and the pure water outlet in the b. step obtains pure water with an NMMO solvent content of 0.98%, and the pure water directly For the w...

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Abstract

The invention discloses a recovery method of spinning waste liquor by means of concentrating, which comprises the technical steps of: a. pretreating: pressurizing low-concentration NMMO (n-methylmorpholine oxide) solution with the weight percentage concentration of 0.1-8.0% to be the pressure of 0.2MPa under the water temperature condition of 20-35DEG C, and then being transported into a precision filter for pretreating by means of precision filtering; b. concentrating by means of reverse osmosis: feeding the pretreated filtered fluid by means of precision filtering into a reverse osmosis component for concentrating by means of the reverse osmosis, wherein the operation pressure is 0.7-6.0MPa when the reverse osmosis membrane component runs; and c. aftertreating: obtaining high-concentration NMMO solution with the weight percentage concentration which is more than 8.0% at an outlet of the concentrated water by means of the reverse osmosis, and feeding the high-concentration NMMO solution into a pressure-reducing distilling tower for further concentration, wherein pure water at the reverse osmosis pure water outlet is directly used for washing a nascent fiber, and the NMMO dissolvent quantity in the pure water is less than 0.1%.

Description

technical field [0001] The invention relates to spinning technology, in particular to a method for concentrating and recovering spinning waste liquid. The spinning waste liquid is 4-methylmorpholine-N-oxide (NMMO), which is produced in the production of cellulose by solvent method . Background technique [0002] In the current solvent-based cellulose fiber production, 4-methylmorpholine-N-oxide (NMMO) is often used as a solvent. This production process will produce a large amount of low-concentration NMMO waste liquid during the washing process of as-spun fibers. In order to enable NMMO to be reused and reduce environmental pollution, certain technical means must be used to concentrate and recover NMMO solvent or do other treatments, which plays an important role in the production of solvent-based cellulose. [0003] The existing domestic NMMO solvent recovery methods are limited to higher concentration of NMMO waste liquid (8-28% coagulation bath mass concentration), and u...

Claims

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Application Information

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IPC IPC(8): C02F9/10C02F9/02C02F1/44
Inventor 张宇峰倪磊孟建强刘恩华王薇程博闻
Owner TIANJIN POLYTECHNIC UNIV
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