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A thin film evaporator for cellulose dissolution

A thin-film evaporator and cellulose dissolving technology, applied in evaporator accessories, dissolution, evaporation, etc., can solve the problems of NMMO and cellulose decomposition, high dissolution temperature vacuum conditions, slow film surface renewal, etc., to achieve easy cellulose dissolution , increase the amount of dissolution, improve the effect of updating frequency and updating degree

Active Publication Date: 2017-03-01
CHINESE TEXTILE ACAD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The equipment is designed with two types of scrapers with angles greater than 0° in the vertical direction and toward the vertical direction. Although this design can increase the production capacity, it also has the problems of slow renewal of the film surface, small amplitude, shallow renewal depth, and in the process of dissolution. There is no mixing effect on the material, which may cause problems such as uneven dissolution
In order to overcome these shortcomings, it is necessary to use very high dissolution temperature and relatively strict vacuum conditions, which not only cause high energy consumption, but also high dissolution temperature may cause the decomposition of NMMO and cellulose, bringing safety to production Hidden danger

Method used

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  • A thin film evaporator for cellulose dissolution
  • A thin film evaporator for cellulose dissolution
  • A thin film evaporator for cellulose dissolution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] A thin film evaporator with an evaporation area of ​​1m 2 , the number of scraper rows is 12, of which there are 6 rows of scrapers arranged vertically, and among the other 6 rows of scrapers arranged obliquely, 2 rows have an angle α of -3°, and the angle α of the remaining 4 rows is 25°. There are 3 teeth on each scraper, the tooth length is 30mm, the tooth length to gap ratio is 1.5:1, the distance between the scraper and the inner wall is 3mm, and the arc length of the scraper section is 40mm. The length of the discharge spiral at the bottom is 300mm, the spiral pitch of the cone section is 60mm, and the spiral pitch of the straight section is 30mm.

[0056]Based on the cellulose percentage of 12%, on the production line of Lyocell fiber with NMMO and water as the solvent, the maximum production capacity of Lyocell fiber can reach 300 tons per year using this thin film evaporator, and the dissolution capacity of the thin film evaporator can reach 0.32 tons / h, the r...

Embodiment 2

[0061] A thin film evaporator with an evaporation area of ​​30m 2 , the number of scraper rows is 24, of which there are 12 rows of scrapers arranged vertically, and among the other 12 rows of scrapers arranged obliquely, 4 rows have an angle α of -5° and are distributed in the lower half, and the remaining 8 rows and The upper half of the scraper column with an angle of -5° is a scraper with an angle α of 20°. The ratio of tooth length to gap on the scraper is 1.5:1, the distance between the scraper and the inner wall is 4mm, and the arc length of the scraper section is 100mm. The length of the bottom discharge screw is 450mm, the screw pitch of the cone section is 80mm, and the screw pitch of the straight section is 50mm.

[0062] Based on the cellulose percentage of 12%, on the production line of Lyocell fiber with NMMO and water as solvent, using this thin film evaporator, the maximum production capacity of Lyocell fiber can reach 8,000 tons / year, and the dissolution capa...

Embodiment 3

[0067] A thin film evaporator with an evaporation area of ​​35m 2 , the number of scraper columns is 24, of which there are 12 rows of vertical scrapers, and among the other 12 rows of oblique scrapers, 2 rows have an angle α of -10° and are distributed in the lower half, and the remaining 10 rows and The upper half of the scraper column with an angle of -10° is all scrapers with an angle α of 15°. The ratio of tooth length to gap on the scraper is 1.8:1, the distance between the scraper and the inner wall is 5mm, and the arc length of the scraper section is 150mm. The length of the bottom discharge screw is 500mm, the screw pitch of the cone section is 100mm, and the screw pitch of the straight section is 80mm.

[0068] Based on a cellulose percentage of 12%, on the production line of Lyocell fibers with NMMO and water as solvents, using this thin film evaporator, the maximum production capacity of Lyocell fibers is 10,000 tons / year, and the film evaporator has a dissolving ...

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Abstract

The invention relates to a film evaporator for cellulose dissolving. The film evaporator comprises a cavity, a rotatable cylindrical rotor arranged in the cavity, and a row or a plurality of rows of scarper plates arranged in the periphery of the rotor along an axial direction, the scarper plates comprise vertically arranged scraper plates and obliquely arranged scraper plates, and the obliquely arranged scraper plates comprise scraper plates having a negative angle to a vertical direction, and scraper plates having a positive angle to the vertical direction. The scraper plates having a negative angle to the vertical direction provide a demixing effect for materials in the dissolving process, and effectively improve the dissolving ability and the dissolving uniformity of the film evaporator per unit area. The dissolving efficiency is improved, so low dissolving temperature and low vacuum degree are used at a certain degree in the selection of process conditions, thereby the material decomposition risk is reduced, and safe production is facilitated.

Description

technical field [0001] The invention relates to a production and application equipment of Lyocell fibers suitable for industrialization using NMMO as a solvent, in particular to a thin film evaporator for cellulose dissolution. Background technique [0002] The cellulose is dissolved in a solvent to form a cellulose solution, and then the solution is spun in a spinning machine to obtain fibers, and the fibers are coagulated in a coagulation bath under the action of stretching to form cellulose fibers. This kind of fiber is called "solution spun cellulose fiber", and its typical representative is viscose fiber. However, the production process of viscose fiber has huge pollution to the atmospheric environment, high production energy consumption, large waste gas and wastewater discharge, which is not conducive to the protection of the ecological environment, and the continuous large-scale development is further restricted. [0003] In recent years, a production method of solut...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D1/22B01D1/30B01F1/00B01F13/06B01F7/18
Inventor 程春祖孙玉山徐纪刚金云峰杨聪徐鸣风王根立安康骆强
Owner CHINESE TEXTILE ACAD
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