Evaporation and dehydration method for N-methylmorpholine-N-oxide solvent in cellulosic fiber production through solvent method

A technology of cellulose fiber and methylmorpholine, which is applied in the fields of fiber chemical characteristics, final product manufacturing, textile/flexible product manufacturing, etc., can solve the problems of no energy-saving measures, large energy consumption, and large energy consumption, so as to reduce energy consumption Consumption, less decomposition products, and the effect of increasing the evaporation temperature

Active Publication Date: 2013-04-17
SHANGHAI JUYOU CHEM ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, the evaporation method mentioned in CN200810301754.5 applied by Yibin Siliya Group Co., Ltd. is a three-effect evaporation, and the claims are all carried out in a vacuum state, and there are no obvious energy-saving measures.
[0009] In summary, in the prior art of N-methylmorpholine-N-oxide (NMMO) evaporation methods, they are all carried out in a vacuum state, without other energy-saving measures, and the energy consumption is relatively large. The efficiency will be more than 1.05 tons of steam / ton of water. Usually, more than 30 tons of water need to be evaporated to produce one ton of Lyocell fiber, which leads to huge energy consumption in the actual production process

Method used

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  • Evaporation and dehydration method for N-methylmorpholine-N-oxide solvent in cellulosic fiber production through solvent method
  • Evaporation and dehydration method for N-methylmorpholine-N-oxide solvent in cellulosic fiber production through solvent method
  • Evaporation and dehydration method for N-methylmorpholine-N-oxide solvent in cellulosic fiber production through solvent method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Get the Lyocell fiber spinning coagulation bath solution that contains NMMO mass percent as 10%, after purification, add 20% phosphoric acid to adjust the pH value to 7, add 100ppm propyl gallate, enter the preheater after fully mixing, make The solvent and the by-product hot water are fully exchanged and preheated to 70°C. Then enter the three-stage two-effect evaporation system, the process is as follows figure 1 As shown, the evaporator is a natural circulation evaporator. The first stage is heated by primary steam, the primary steam temperature is 120°C, the primary heating chamber temperature is 115°C, the primary material temperature is 107°C, the primary operating pressure is 120kpa, the primary secondary steam temperature is 103°C, and the primary discharge concentration 26%. The second stage is heated by the secondary steam generated by the first stage, the temperature of the secondary heating chamber is 101°C, the temperature of the secondary material is 65°...

Embodiment 2

[0038] Take the Lyocell fiber spinning coagulation bath solution containing 15% NMMO mass percentage, add 20% phosphoric acid after purification to adjust the pH value to 8, add 200ppm hydrogen peroxide, and enter the preheater after fully mixing to make the solvent and side The hot water produced is fully heat exchanged and preheated to 66°C. Then enter the four-stage three-effect evaporation system, the process is as follows figure 2As shown, the evaporator is a forced circulation evaporator. The first stage is heated by primary steam, the primary steam temperature is 117°C, the primary heating chamber temperature is 115°C, the primary material temperature is 108°C, the primary operating pressure is 130kpa, the primary secondary steam temperature is 105°C, and the primary discharge concentration twenty three%. The second stage is heated by the secondary steam generated by the first stage, the temperature of the secondary heating chamber is 101°C, the temperature of the se...

Embodiment 3

[0041] Get the Lyocell fiber spinning coagulation bath solution that contains NMMO mass percent as 20%, after purification, add 20% phosphoric acid to adjust the pH value to 6.5, add 200ppm oxalic acid, enter the preheater after fully mixing, make the solvent and side The hot water produced is fully heat exchanged and preheated to 70°C. Then enter the five-stage two-effect evaporation system, the process is as follows image 3 As shown, the first and second evaporators use rising film evaporators, and the third, fourth and fifth use falling film evaporators. The first stage is heated by primary steam, the primary steam temperature is 118°C, the primary heating chamber temperature is 115°C, the primary material temperature is 108°C, the primary operating pressure is 130kpa, the primary secondary steam temperature is 105°C, and the primary discharge concentration twenty three%. The second stage is heated by primary steam, the temperature of the secondary heating chamber is 115...

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Abstract

The invention provides an evaporation and dehydration method for an N-methylmorpholine-N-oxide (NMMO) solvent in cellulosic fiber production through a solvent method, and the method comprises the following steps of: regulating the pH value of solvent NMMO between 5-9, adding 20-1000ppm of stabilizer, then preheating, putting the solvent of NMMO into an evaporation system above three-level for evaporation above three-level, and finally concentrating till the requirement of the technology. And in the process of evaporation above three-level, water vapor evaporated from solvent of low concentration can be used as heat source for evaporation of solvent of high concentration. According to the method, the evaporation temperature of the solvent of NMMO is increased by improving the stability of the solvent, so that the steam can be reutilized, energy consumption for evaporation of solvent of NMMO is lowered remarkably, and the purpose of energy conservation is achieved.

Description

technical field [0001] The invention belongs to the technical field of chemical fiber technology, and relates to a method for evaporating and dehydrating N-methylmorpholine-N-oxide (NMMO) solvent in the production of cellulose fiber by solvent method. Background technique [0002] The stock of cellulose in nature is about 700 billion tons, and it is still being regenerated at a rate of 40 billion tons per year. It is the most abundant natural renewable resource on the earth. Cotton, hemp and other cellulose fibers cannot be increased in large quantities due to the constraints of land, climate, water resources, etc. The main raw material of synthetic fibers, petroleum, is a one-time resource and will eventually be exhausted. The raw materials of artificial cellulose fibers can be obtained from almost all plants. Obtained from orange stalks, it can be described as inexhaustible and inexhaustible. Therefore, the development of man-made cellulose fibers is a long-term plan to pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F13/02
CPCY02P70/62
Inventor 蔡剑韩增强
Owner SHANGHAI JUYOU CHEM ENG
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