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Method for separating nitromethane-methanol-cyclohexane azeotrope through heat integrated pressure-swing distillation

A technology for nitromethane and cyclohexane, which is applied in the field of heat-integrated pressure swing distillation to separate nitromethane-methanol-cyclohexane azeotrope, can solve problems such as high energy consumption, no heat integration, and the like, and achieve product yield High, achieve thermal integration, reduce equipment investment costs

Active Publication Date: 2017-08-01
QINGDAO UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is no ternary azeotrope in this system, and this patent does not realize heat integration, resulting in high energy consumption

Method used

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  • Method for separating nitromethane-methanol-cyclohexane azeotrope through heat integrated pressure-swing distillation
  • Method for separating nitromethane-methanol-cyclohexane azeotrope through heat integrated pressure-swing distillation
  • Method for separating nitromethane-methanol-cyclohexane azeotrope through heat integrated pressure-swing distillation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Feed flow rate 1000kg / h, temperature 25 DEG C, pressure 1atm, mass composition: nitromethane 45%, methyl alcohol 35%, hexanaphthene 20%; Pressurization tower (T1) theoretical plate number is 50, and raw material liquid is by the first 40 plates are introduced, the circulating feed position is the 40th plate, the operating pressure is 4atm, the reflux ratio is 3.0, and the tower diameter is about 0.55m; the theoretical plate number of the decompression tower (T2) is 31, and the pressure tower (T1 ) The production liquid at the top of the tower is introduced by the 16th plate, the operating pressure is 0.5atm, the reflux ratio is 0.1, and the tower diameter is about 0.36m; The production liquid at the top of the tower is introduced from the 23rd plate, the operating pressure is 4atm, the reflux ratio is 1.0, and the tower diameter is about 0.39m; the purity of the product after separation is 99.52%, the yield is 99.52%, and the purity of methanol is 99.51 %, the yield is ...

Embodiment 2

[0047] Feed flow rate 1000kg / h, temperature 25°C, pressure 1atm, mass composition: nitromethane 55%, methyl alcohol 25%, hexanaphthene 20%; Pressurization tower (T1) theoretical plate number is 55, and raw material liquid is by the first 45 plates are introduced, the circulating feed position is the 45th plate, the operating pressure is 4atm, the reflux ratio is 3.3, and the tower diameter is about 0.51m; the theoretical plate number of the decompression tower (T2) is 30, and the pressure tower (T1 ) The production liquid at the top of the tower is introduced by the 15th plate, the operating pressure is 0.5atm, the reflux ratio is 0.15, and the tower diameter is about 0.35m; The production liquid at the top of the tower is introduced from the 21st plate, the operating pressure is 4atm, the reflux ratio is 1.2, and the tower diameter is about 0.38m; the purity of the product after separation is 99.82%, the yield is 99.72%, and the purity of methanol is 99.61 %, the yield is 99....

Embodiment 3

[0053] Feed flow rate 1000kg / h, temperature 25 ℃, pressure 1atm, mass composition: nitromethane 50%, methyl alcohol 30%, hexanaphthene 20%; Pressurization tower (T1) theoretical plate number is 53, and raw material liquid is by the first 42 plates are introduced, the circulating feed position is the 42nd plate, the operating pressure is 4atm, the reflux ratio is 3.2, and the tower diameter is about 0.53m; the theoretical plate number of the decompression tower (T2) is 32, and the pressure tower (T1 ) The production liquid at the top of the tower is introduced from the 17th plate, the operating pressure is 0.5atm, the reflux ratio is 0.2, and the tower diameter is about 0.33m; The production liquid at the top of the tower is introduced from the 25th plate, the operating pressure is 4atm, the reflux ratio is 1.3, and the tower diameter is about 0.38m; the purity of the product after separation is 99.90%, the yield is 99.90%, and the purity of methanol is 99.90% %, the yield is 9...

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Abstract

The invention relates to a method for separating a nitromethane-methanol-cyclohexane azeotrope through heat integrated pressure-swing distillation. Under the normal pressure, a pairwise azeotropic phenomenon exists among nitromethane, methanol and cyclohexane, namely, three binary azeotropes are contained, and a ternary azeotrope is formed among the three components and is difficult to separate through ordinary distillation. The method comprises the following steps: separating high-purity nitromethane, methanol and cyclohexane by using a feature that composition deviation occurs among three groups of azeotropic systems, namely, the nitromethane, the methanol and the cyclohexane along with a pressure change in a three-tower pressure-swing distillation manner; meanwhile, pre-heating nitromethane-methanol-cyclohexane serving as a raw material through a heat integration technology by taking a part of steam coming from the top of a pressurizing tower (T1) as heat flow of a heat exchanger (H); making the other part of steam coming from the top of the pressurizing tower (T1) pass through a reboiler (R2) for exchanging heat with methanol liquid coming from the bottom of a depressurizing tower (T2). By adopting the method, the problem of difficulty in separating the azeotropic system through the ordinary distillation is solved, and efficient utilization of energy is realized by adopting the heat integration technology.

Description

[0001] 【Technical field】 [0002] In the field of separation and purification in the chemical industry, it specifically relates to a method for heat-integrated pressure-swing rectification to separate nitromethane-methanol-cyclohexane azeotrope, especially suitable for three binary azeotropes in the ternary system, and three groups A system of ternary azeotropes will be formed between the components. [0003] 【Background technique】 [0004] Nitroalkane is the simplest organic nitro compound. It has great polarity and can be miscible with many organic compounds. It is a good solvent and can be used as nitrocellulose, cellulose acetate, vinyl resin, paint, etc. It can also be used to prepare explosives, rockets, medicines, dyes, insecticides, fungicides, gasoline additives, etc. Methanol is one of the basic organic raw materials, usually used as solvent, antifreeze, fuel or neutralizing agent. Cyclohexane, a type of cycloalkane, also known as hexahydrobenzene, is often used as ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/16C07C205/02C07C29/74C07C29/80C07C31/04C07C7/00C07C7/04C07C13/18
CPCC07C7/005C07C7/04C07C29/74C07C29/80C07C201/16C07C205/02C07C31/04C07C13/18
Inventor 朱兆友张霞秦斌白文婷王英龙
Owner QINGDAO UNIV OF SCI & TECH