Method for separating acetic acid from water by rectification of acetic acid dehydrating tower

A technology for acetic acid dehydration and rectification separation, which is applied in the separation/purification, fractionation, organic chemistry and other directions of carboxylic acid compounds, and can solve the problems of high operating costs, high energy consumption for acetic acid dehydration, and high equipment manufacturing costs

Active Publication Date: 2012-05-16
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is the problem of high energy consumption, high equipment manufacturing cost and high operating cost in the acetic acid dehydration process in the prior art, and a new method for rectifying and separating acetic acid and water in the acetic acid dehydration tower is provided

Method used

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  • Method for separating acetic acid from water by rectification of acetic acid dehydrating tower
  • Method for separating acetic acid from water by rectification of acetic acid dehydrating tower
  • Method for separating acetic acid from water by rectification of acetic acid dehydrating tower

Examples

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Effect test

Embodiment 1

[0032] use figure 1 Shown flow process, dilute acetic acid aqueous solution adopts the mode of azeotropic rectification to carry out dehydration, and acetic acid aqueous solution 1 (wherein acetic acid concentration is 38 mass %) enters acetic acid dehydration tower 2 from the middle, after rectification separation, tower top obtains gaseous phase stream 3, The tower kettle obtains the liquid phase stream 7; the stream 3 is divided into the stream 5 and the stream 6 after the heat exchange and condensation of the condenser 4, and the stream 5 enters the follow-up process as the tower top product discharge, and the stream 6 returns to the top of the acetic acid dehydration tower 2; the stream 7 After heat exchange by the reboiler 8, it is divided into a stream 9 and a stream 10, the stream 9 returns to the bottom of the 2, and the stream 10 enters the subsequent process as a product discharged from the tower kettle. The concentration of acetic acid in the discharge from the bot...

Embodiment 2

[0043] Same as [Example 1], except that the heat exchange medium water is changed to cyclohexane, and the pressure of cyclohexane on the shell side of the tower top condenser is normal pressure, and the remaining operating pressures remain unchanged.

[0044] After the gas-liquid separation tank is added in the method of the invention, the operating state of the condenser is more stable. When there is a gas phase in the stream, the entry of the gas phase will cause the vibration of the condenser and damage the equipment; when the gas phase is separated, the entry of the pure liquid stream can stabilize the operation of the condenser, thereby improving the service life of the device and reducing operation. cost.

[0045] The energy consumption is shown in Table 1, and the heat transfer efficiency and equipment cost are shown in Table 2.

[0046] As can be seen from Table 1, compared with pressurized rectification, every ton of concentrated acetic acid-water solution produced, ...

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Abstract

The invention relates to a method for separating acetic acid from water by rectification of an acetic acid dehydrating tower, mainly solving the problems of high energy consumption, high equipment manufacture cost and high operation cost in a process of dehydrating acetic acid in the prior art. The method comprises the steps of: carrying out azeotropic distillation by adopting the acetic acid dehydrating tower for dehydrating, adopting water or cyclohexane in a heat pump circulation as a heat exchange medium, absorbing heat released by condensation of top discharged materials of the acetic acid dehydrating tower through a heat exchange medium in a closed heat pump process, raising the temperature after the heat exchange medium absorbs the heat of the top discharged materials and then compressed, desuperheating high-temperature overheat steam by a desuperheating device to form saturated steam, introducing into a kettle reboiler and exchanging heat with bottom discharged materials; throttling and decompressing the steam subjected to kettle heat exchange and then entering into a gas and liquid separation tank, enabling the separated liquid phase to a tower top condenser for exchanging heat, mixing the separated gas phase with gas at an outlet of the tower top condenser together to enter into a compressor for exchanging heat with a kettle again. According to the technical scheme, the problem is better solved, thus the invention can be applied to industrial production of separating the acetic acid from the water.

Description

technical field [0001] The invention relates to a method for rectifying and separating acetic acid and water in an acetic acid dehydration tower. Background technique [0002] In the process of oxidizing p-xylene to produce terephthalic acid, acetic acid is usually used as an organic solvent. The large amount of water formed during the oxidation dilutes the acetic acid solvent, which is required in the appropriate concentration for the reaction. In order to ensure the concentration of acetic acid in the solvent, an acetic acid dehydration tower is usually used to separate the excess water in the solvent. With the expansion of production scale, the operating cost of acetic acid dehydration tower is increasing day by day. [0003] Conventional direct rectification dehydration due to relatively low volatility when the concentration of acetic acid is low, the method of increasing the number of trays and increasing the reflux ratio is usually used to reduce the concentration of...

Claims

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Application Information

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IPC IPC(8): B01D3/14C07C51/46C07C53/08
Inventor 杨军徐涵正钟亮陈迎李真泽何勤伟
Owner CHINA PETROLEUM & CHEM CORP
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