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An energy-saving method for the separation of ethyl acetate and n-hexane by azeotropic combined pressure swing distillation

An ethyl acetate and pressure swing rectification technology, applied in chemical instruments and methods, distillation purification/separation, carboxylate preparation, etc., can solve the problems of low recovery purity and difficult separation of entrainer, and achieve high cost performance, Simple equipment, high purity effect

Inactive Publication Date: 2018-11-16
SOUTHWEST PETROLEUM UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide an energy-saving method for separating ethyl acetate and n-hexane through azeotropic combined pressure swing distillation for the shortcomings of the existing technology for separating ethyl acetate and n-hexane
This technology effectively solves the problems of difficult separation of azeotrope formed by ethyl acetate and n-hexane and low purity of recovery of entrainer. It has the characteristics of simple process flow, less equipment investment, convenient maintenance, no pollution, and energy saving.

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  • An energy-saving method for the separation of ethyl acetate and n-hexane by azeotropic combined pressure swing distillation

Examples

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Embodiment example 1

[0025] Such as figure 1Shown, a kind of energy-saving method of azeotropic and pressure swing rectification joint separation ethyl acetate and normal hexane, its concrete steps are as follows:

[0026] (1) Azeotropic distillation

[0027] For the organic waste liquid produced in the production process of an enterprise, its composition is: ethyl acetate mass fraction 31.00%, n-hexane mass fraction 69.00%, mass flow rate 1000.00kg / h, sent to the azeotropic essence through the raw material feeding pipeline Distillation tower 8. Simultaneously, be the entrainer methyl alcohol of 275.20kg / h with mass flow rate, send into azeotropic rectification column 8 together by solvent feeding pipeline, carry out azeotropic rectification, the ethyl acetate and methyl alcohol and normal hexane form Azeotrope separation. Wherein, the feed position of ethyl acetate and normal hexane is the 23rd tray, the feed position of entrainer methyl alcohol is the 4th tray, the absolute pressure of azeotr...

Embodiment example 2

[0035] The specific steps of an energy-saving method for the joint separation of ethyl acetate and n-hexane by azeotropic and pressure swing rectification are the same as the implementation case 1, wherein:

[0036] In the (1) step, the composition of the organic waste liquid is: ethyl acetate mass fraction 40.00%, normal hexane mass fraction 60.00%, mass flow rate is 1000.00kg / h, and the mass flow rate of methanol entrainer is 239.50kg / h. The feed position of ethyl acetate and n-hexane entering the azeotropic rectification column 8 is the 25th tray, the feed position of the entrainer methanol is the 4th tray, the absolute pressure of the azeotropic rectification column 8 operation is 0.10MPa, the total number of theoretical plates is 35, and the operating reflux ratio is 3.0. The temperature of the ethyl acetate liquid phase stream that is separated at the bottom of the azeotropic distillation tower 8 is 76.29 ° C, and the gas phase stream of methanol and n-hexane azeotrope i...

Embodiment example 3

[0041] The specific steps of an energy-saving method for the joint separation of ethyl acetate and n-hexane by azeotropic and pressure swing rectification are the same as the implementation case 1, wherein:

[0042] In the 1st step, the composition of organic waste liquid is: ethyl acetate mass fraction 61.00%, n-hexane mass fraction 39.00%, mass flow rate is 1000.00kg / h, and the mass flow rate of methanol entrainer is 161.00kg / h. The feeding position of ethyl acetate and n-hexane entering the azeotropic rectification column 8 is the 20th tray, the feed position of the entrainer methanol is the 6th tray, and the absolute pressure of the azeotropic rectification column 8 operation is 0.10MPa, the total number of theoretical plates is 31, and the operating reflux ratio is 5.3. The temperature of the liquid phase stream of ethyl acetate separated at the bottom of the azeotropic rectification tower 8 is 74.40°C, and the vapor phase stream of methanol and n-hexane azeotrope is sepa...

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Abstract

The invention discloses an energy-saving azeotropic joint variable pressure rectification technology for separating ethyl acetate and n-hexane, belonging to the field of separation and purification inchemical industry. According to the technology, organic waste liquids like ethyl acetate and n-hexane produced in production of rubber, textile fabric, oil paint and medicines undergoes azeotropic rectification with methanol as an azeotropic agent and then undergoes variable pressure rectifications including pressurized rectification and low-pressure rectification, so as to obtain highly pure ethyl acetate, n-hexane and methanol, and energy is saved due to adoption of heat integration. The technology is simple, and is convenient to operate; the process is highly continuous, is highly controllable, and consumes less energy; the product is highly pure and contains fewer impurities; the technology can recycles resources and generates no waste gas, waste liquid and waste slag, thereby protecting environment and saving energy. The technology can be widely applied to recycling of organic waste liquid in industry, and is particularly suitable for recycling of ethyl acetate and n-hexane wasteliquid generated in production of large, medium and small enterprises.

Description

technical field [0001] The invention belongs to the field of chemical separation and purification, and in particular relates to an energy-saving method for separating ethyl acetate and n-hexane through azeotropic combined pressure swing rectification. Background technique [0002] Both n-hexane and ethyl acetate are important organic solvents widely used in fields such as rubber, textiles, paints and pharmaceuticals, and these solvents must be completely removed in the final product, thus forming an organic solvent containing n-hexane and ethyl acetate waste liquid. The boiling point of n-hexane is 68.74°C, the boiling point of ethyl acetate is 77.06°C, the two will form the lowest azeotrope under normal pressure, the azeotropic temperature is 68.00°C, and the azeotropic composition contains ethyl acetate mass fraction 34.30%, The mass fraction of n-hexane is 65.70%, which cannot be separated efficiently by conventional rectification methods. In order to avoid waste of res...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C67/54C07C69/14C07C7/06C07C7/04C07C13/18C07C29/80C07C31/04
Inventor 诸林吕利平李航刘慧敏吴鹏斌
Owner SOUTHWEST PETROLEUM UNIV