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Evaporation method of nmmo

A technology of one-effect evaporation and two-effect evaporation, which is applied in the direction of organic chemistry, can solve problems such as affecting material supply, reducing stability, affecting continuous production of the system, etc., to achieve the effect of ensuring continuous operation and enhancing stability

Inactive Publication Date: 2012-02-22
SHANGHAI LYOCELL FIBER DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, if a single-effect evaporation method is used, the stability of the system will be reduced. If the concentration of NMMO entering the evaporation is low, and it is evaporated to a concentration of 80-87%, the evaporation time will be extended, which will affect the supply to the subsequent section. , it will affect the continuous production of the whole system in severe cases

Method used

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Experimental program
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Effect test

Embodiment 1

[0037] The NMMO solution concentration of the first-effect feed is 10%, the heating steam temperature is 102°C, the first-effect evaporation temperature is 57°C, the first-effect vacuum degree is 14KPa, the cooling water temperature is 20°C, and the first-effect discharge set concentration is 52%. The second-effect evaporation temperature is 91°C, the second-effect vacuum degree is 7KPa, the chilled water temperature is -3°C, the holding water temperature is 92°C, and the second-effect output concentration is 80%.

Embodiment 2

[0039] The NMMO solution concentration of the first-effect feed is 17%, the heating steam temperature is 102°C, the first-effect evaporation temperature is 59°C, the first-effect vacuum degree is 13KPa, the cooling water temperature is 25°C, and the first-effect discharge set concentration is 56%. The second-effect evaporation temperature is 88°C, the second-effect vacuum degree is 5KPa, the chilled water temperature is -2°C, the holding water temperature is 93°C, and the second-effect output concentration is 82%.

Embodiment 3

[0041] The NMMO solution concentration of the first-effect feed is 24%, the heating steam temperature is 101°C, the first-effect evaporation temperature is 52°C, the first-effect vacuum degree is 11KPa, the cooling water temperature is 28°C, and the first-effect discharge set concentration is 63%. The second-effect evaporation temperature is 90°C, the second-effect vacuum is 3KPa, the chilled water temperature is -4°C, the holding water temperature is 95°C, and the second-effect output concentration is 85%.

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Abstract

The invention relates to a method for evaporating the low-concentration solvent NMMO recovered in the production process of solvent-based cellulose fibers. In the method, the recovered and purified low-concentration NMMO solution reaches a certain concentration through first-effect evaporation, and then undergoes second-effect evaporation. After reaching the concentration required by the production process, it is sent to the finished product tank. Through the NMMO evaporation method of the present invention, the stability of the entire production system is enhanced, and the continuous operation of production is guaranteed.

Description

technical field [0001] The invention designs a method for evaporating a solution, and in particular relates to a method for evaporating low-concentration solvent NMMO recovered in a solvent-based cellulose fiber production process. Background technique [0002] In the production process of solvent-based cellulose fibers, NMMO (N-methylmorpholine-N-oxide) is used as a solvent. Due to its high price, it needs to be recycled and reused. Therefore, the NMMO solution in the system is recycled after Purify to remove impurities. [0003] Generally, after recovery, the concentration of NMMO purified to remove impurities is 10% to 30%. Since the concentration of NMMO solution is lower than 72%, it loses its ability to dissolve cellulose, so it is necessary to evaporate and concentrate the recovered low-concentration NMMO solution to a high concentration. Concentration, usually the concentration of NMMO used as a solvent is 80% to 87%, therefore, it needs to be evaporated to a concen...

Claims

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Application Information

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IPC IPC(8): C07D295/24
Inventor 孙海龙姜琨郑殿海王新王贤清
Owner SHANGHAI LYOCELL FIBER DEV
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