Method for separating methylcyclohexane and toluene through differential pressure thermal coupling extractive rectification

A differential pressure thermal coupling, methylcyclohexane technology, applied in the field of rectification, can solve problems such as low thermodynamic efficiency, and achieve good economic and social benefits.

Inactive Publication Date: 2012-09-19
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the extractive distillation column, the heat introduced into the reboiler of the distillation column is discharged from the condenser after passing through the distillation column, and most of the energy is lost in such as the pressure drop of the column and the temperature difference through the heat exchanger, while Only part of the energy is used to reduce the entropy of the product of the distillation column, and its thermodynamic efficiency is low

Method used

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  • Method for separating methylcyclohexane and toluene through differential pressure thermal coupling extractive rectification
  • Method for separating methylcyclohexane and toluene through differential pressure thermal coupling extractive rectification
  • Method for separating methylcyclohexane and toluene through differential pressure thermal coupling extractive rectification

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Experimental program
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Effect test

Embodiment 1

[0017] Embodiment 1: as figure 1 Shown flow process, the number of theoretical plates in each area is as shown in Table 1, and the feed flow rate and composition are as shown in Table 2, and the solvent ratio is 3.01, and the feed position (from top to toluene) of mixed extractant, methylcyclohexane and toluene Bottom numbers) are the 5th theoretical plate of the atmospheric column (1) and the 4th theoretical plate of the vacuum column (2) in turn, and the feeds are both at 25°C. Differential pressure thermal coupling extractive distillation column Atmospheric column (1) top reflux ratio is 8, phenol recovery tower (3) top reflux ratio is 5, each flow rate and composition are as shown in Table 2, Atmospheric column (1) top Temperature is 100.3 ℃, and vacuum tower (2) still temperature is 79.9 ℃, and phenol recovery tower (3) top temperature is 115.2 ℃, and still temperature is 193.1 ℃, and normal pressure tower (1) and phenol recovery tower (3) normal pressure Operation, deco...

Embodiment 2

[0022] Embodiment 2: as figure 1 process shown. Feed composition, feed heat state, feed position and the number of theoretical plates in each region are the same as in Example 1, and the solvent ratio is 3.2. The reflux ratio at the top of the differential pressure thermal coupling extractive distillation column (1) is 7.4, and the reflux ratio at the top of the phenol recovery tower (3) is 5.8. The flow rates and compositions of the various streams are shown in Table 3. Temperature is 100.6 ℃, and vacuum tower (2) still temperature is 80.3 ℃, and phenol recovery tower (3) top temperature is 114.4 ℃, and still temperature is 192.9 ℃, normal pressure tower (1) and phenol recovery tower (3) normal pressure Operation, decompression tower (2) pressure is 0.018MPa. The mole fraction of the obtained methylcyclohexane was 99.31%. To meet the separation requirements of the same product, the total energy consumption required by this process is 4810.81kW, and the total energy consump...

Embodiment 3

[0025] Embodiment 3: as figure 1 process shown. Feed composition, feed heat state, feed position and the number of theoretical plates in each region are the same as in Example 1, except that the solvent ratio is 2.8. The reflux ratio at the top of the differential pressure thermal coupling extractive distillation column (1) is 8.7, and the reflux ratio at the top of the methanol recovery tower (3) is 5.2. The flow rates and compositions of the various streams are shown in Table 4. Temperature is 103.2 ℃, and vacuum tower (2) still temperature is 81.6 ℃, and phenol recovery tower (3) top temperature is 114.8 ℃, and still temperature is 192.7 ℃, normal pressure tower (1) and phenol recovery tower (3) normal pressure Operation, decompression tower (2) pressure is 0.025MPa. The mole fraction of the obtained methylcyclohexane was 99.03%. To achieve the same acetic acid conversion rate and product separation requirements, the total energy consumption required by this process is 4...

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Abstract

The invention provides a method for separating methylcyclohexane and toluene through differential pressure thermal coupling extractive rectification. According to the method, phenol is used as an extracting agent, and an adopted device comprises an atmospheric tower and a vacuum tower of a differential pressure thermal coupling extractive rectification tower, a phenol reclaiming tower, a compressor, a main heat exchanger, an auxiliary condenser, a heat exchanger, a condenser and a reboiler. The compressor is arranged between the vacuum tower and the atmospheric tower of the differential pressure thermal coupling extractive rectification tower; steam produced by the tower top of the vacuum tower enters the tower bottom of the atmospheric tower after being pressurized and heated by the compressor; and the latent heat of the steam from tower top of the atmospheric tower is used for heating the main heat exchanger arranged at the tower bottom of the vacuum tower so as to carry out thermal coupling between the two towers, thereby realizing the substantial energy saving of the rectification process and taking full advantages of differential pressure thermal coupling rectification and extractive rectification. The method provided by the invention can be used for separating the methylcyclohexane with the purity of 99%; and compared with the conventional extractive rectification tower, the rectification column adopted in the method can save energy by more than 30%.

Description

Technical field: [0001] The invention belongs to the technical field of rectification, and relates to a separation method combining differential pressure thermal coupling rectification and extractive distillation, specifically a method for separating methylcyclohexane and toluene by using a differential pressure thermal coupling extraction distillation tower, While the separation of methylcyclohexane and toluene can be completed, the energy saving can be more than 30% compared with conventional extraction and rectification devices. Background technique: [0002] Methylcyclohexane can be used as a solvent for rubber, paint, varnish, oil extraction solvent, etc. It can also be used in organic synthesis and used as a standard for calibrating thermometers. The mixture of methylcyclohexane and toluene is widely used as reaction raw material and solvent in industries such as organic synthesis, printing and medicine, so it is of great significance to effectively separate methylcycl...

Claims

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Application Information

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IPC IPC(8): C07C13/18C07C7/08
CPCY02P20/10Y02P20/50
Inventor李军孙兰义王俊马占华刘雪暖李青松
OwnerCHINA UNIV OF PETROLEUM (EAST CHINA)