A separation method for recovering an isopropanol-isooctane azeotrope mixture in industrial production

Abstract

This invention relates to a method for the continuous production of isopropanol-isooctane azeotropic mixtures by extractive distillation, characterized in that the apparatus for implementing this method mainly comprises the following parts: distillation column 1 (T1), distillation column 2 (T2), condenser 1 (CL1), condenser 2 (CL2), top storage tank 1 (C1), top storage tank 2 (C2), reboiler 1 (H1), reboiler 2 (H2), cooler (COL), and centrifugal pump 1 (P1); wherein distillation column 1 (T1)... 1) The bottom stream enters distillation column 2 (T2), and high-purity isopropanol is collected from the top stream of distillation column 1 (T1). The bottom product of distillation column 1 (T1) enters distillation column 2 (T2), and high-purity isooctane is collected from the top stream of distillation column 2 (T2), completing the separation of components. High-purity extractant is obtained at the bottom of distillation column 2 (T2), and after passing through a cooler (COL), it enters a centrifugal pump (P1). After cooling, extractant is added and then refluxed to distillation column 1 (T1). The extractant used is essentially non-volatile, which reduces extractant loss and allows for reuse, thereby reducing separation costs.

Description

[Technical Field]

[0001] This invention belongs to the field of chemical separation and purification, specifically relating to a separation method for recovering isopropanol-isooctane azeotropic mixtures in industrial production. [Background Technology]

[0002] Isopropanol and isooctane are important organic substances. Isopropanol is widely used in the chemical industry to produce chemicals such as acetone, hydrogen peroxide, and methyl isobutyl ketone, and can also be used to produce isopropyl esters and isopropyl fatty acids. In addition, it has uses as a solvent, in pharmaceuticals, as an antifreeze, and in other industrial products. Due to its stable physical and chemical properties, isooctane is frequently used as a solvent or reaction medium in petrochemical and organic synthesis fields. Under normal pressure, isooctane and isopropanol can form an azeotrope, making separation difficult.

[0003] This invention focuses on the isopropanol-isooctane azeotrope, utilizing the significant influence of the extractant on its relative volatility to achieve high-purity separation of isopropanol-isooctane mixtures. The purity of both isopropanol and isooctane after separation is above 99.9%. [Summary of the Invention]

[0004] [Technical problem to be solved]

[0005] The purpose of this invention is to provide a method for producing isopropanol and isooctane, and to provide the use of N,N-dimethylacetamide or glycerol as an extractant in extractive distillation to separate isopropanol-isooctane mixtures, thereby achieving the recovery and utilization of isopropanol and isooctane.

[0006] [Technical Solution]

[0007] The present invention is achieved through the following technical solution.

[0008] A separation method for recovering isopropanol-isooctane azeotropic mixtures in industrial production is characterized by an apparatus comprising the following main components: distillation column 1 (T1), distillation column 2 (T2), condenser 1 (CL1), condenser 2 (CL2), top storage tank 1 (C1), top storage tank 2 (C2), reboiler 1 (H1), reboiler 2 (H2), cooler (COL), and centrifugal pump 1 (P1); the replenished fresh extractant is mixed with the circulating extractant and then piped to distillation column 1 (T1). The distillation column 1 (T1) is connected to the distillation column 2 (T2) via a pipeline; the distillation column 2 (T2) is connected to the distillation column 1 (T1) via a pipeline, first through a cooler (COL) and then through a centrifugal pump 1 (P1); condenser 1 (CL1) is connected to the distillation column 1 (T1) and the top storage tank 1 (C1); condenser 2 (CL2) is connected to the distillation column 2 (T2) and the top storage tank 2 (C2); reboiler 1 (H1) and reboiler 2 (H2) are connected to the distillation column 1 (T1) and the distillation column 2 (T2) respectively.

[0009] A method for separating isopropanol-isooctane azeotropic mixtures in industrial production using the above-described apparatus includes the following steps:

[0010] (1) The mixture of isopropanol and isooctane feedstocks and the extractant are added to the distillation column 1 (T1) from the bottom part and the top part of the column, respectively. In the distillation column 1 (T1), isopropanol is separated. Part of the bottom stream of distillation column 1 (T1) is returned to distillation column 1 (T1) after heat exchange in reboiler 1 (H1), and part of it is fed into distillation column 2 (T2). Isopropanol is condensed by condenser 1 (CL1) and enters the top storage tank 1 (C1). Part of it is refluxed and the other part is collected from the top of distillation column 1 (T1).

[0011] (2) In the distillation column 2 (T2), isooctane is separated. Part of the bottom stream of distillation column 2 (T2) is returned to distillation column 2 (T2) after heat exchange in reboiler 2 (H2), and part of the reflux is first passed through cooler (COL) and then fed into distillation column 1 (T1) by centrifugal pump 1 (P1). After being condensed by condenser 2 (CL2), isooctane enters the top storage tank 2 (C2), part of which is refluxed and the other part is collected from the top of distillation column 2 (T2).

[0012] According to claim 1, the method is characterized in that: the number of trays in distillation column 1 (T1) is 30 to 60, and the temperature is 50 to 220°C; the number of trays in distillation column 2 (T2) is 10 to 50, and the temperature is 50 to 220°C.

[0013] According to another preferred embodiment of the present invention, the extractant is N,N-dimethylacetamide or glycerol.

[0014] According to another preferred embodiment of the present invention, the feed flow rate of the extractant to the isopropanol-isooctane mixture is 0.1 to 5 by mass.

[0015] According to another preferred embodiment of the present invention, the isopropanol-isooctane mixture has an isopropanol mass fraction of 55.1% and an isooctane mass fraction of 44.9%.

[0016] According to another preferred embodiment of the present invention, the isopropanol recovered from the top of distillation column 1 (T1) has a purity higher than 99.9% and a yield higher than 99.9%; the isooctane recovered from the top of distillation column 2 (T2) has a purity higher than 99.9% and a yield higher than 99.9%.

[0017] [Beneficial Effects]

[0018] Compared with the prior art, the present invention has the following main advantages:

[0019] (1) The present invention separates the isopropanol-isooctane mixture to obtain high-purity isooctane and isooctane, thereby breaking through the separation problem of isopropanol-isooctane and achieving the purpose of recovering high-purity isooctane and isooctane.

[0020] (2) The process is simple, requires less investment and equipment, and the isopropanol and isooctane after separation have high purity.

[0021] (3) The extractant used in this project is basically non-volatile, which can reduce extractant loss, avoid secondary pollution to the environment caused by isopropanol and isooctane, and can be reused, which can reduce separation costs. [Attached Image Description]

[0022] Figure 1 This is a process flow diagram of the present invention for producing a mixture of isopropanol and isooctane.

[0023] In the diagram, T1 is the distillation column; T2 is the distillation column; CL1 is the condenser; CL2 is the condenser; COL is the cooler; H1 is the reboiler; H2 is the reboiler; P1 is the centrifugal pump; C1 is the top storage tank; and C2 is the top storage tank.

Detailed Implementation Methods

[0024] Example 1:

[0025] The feed flow rate is 7633.642 kg / h, containing 55.1% isopropanol and 44.9% isooctane by mass. Distillation column 1 (T1) has 46 theoretical plates. The isopropanol-isooctane mixture enters from the bottom of column 1 (T1), with N,N-dimethylacetamide as the extractant. The N,N-dimethylacetamide extractant enters from the top of column 1 (T1) at a flow rate of 13068.24 kg / h. 4206.845 kg / h of 99.9% isopropanol is obtained at the top of column 1 (T1). The isooctane-extractant mixture enters from the bottom of distillation column 2 (T2) at a flow rate of 16495.037 kg / h. Distillation column 2 (T2) has 13 theoretical plates, completing the separation of isooctane and the extractant. The distillation column operates at atmospheric pressure. After separation, the purity of isopropanol is 99.9% and the yield is 99.9%, and the purity of isooctane is 99.9% and the yield is 99.9%.

[0026] Example 2:

[0027] The feed flow rate is 7633.642 kg / h, containing 55.1% isopropanol and 44.9% isooctane by mass. Distillation column 1 (T1) has 37 theoretical plates. The isopropanol-isooctane mixture enters from the bottom of column 1 (T1), and glycerol is used as the extractant, entering from the top of column 1 (T1) at a flow rate of 13814.208 kg / h. 4206.952 kg / h of 99.9% isopropanol is obtained at the top of column 1 (T1). The isooctane-extractant mixture enters from the bottom of distillation column 2 (T2) at a flow rate of 17240.898 kg / h. Distillation column 2 (T2) has 32 theoretical plates, completing the separation of isooctane and the extractant. The distillation column operates at atmospheric pressure. After separation, the purity of isopropanol is 99.9% and the yield is 99.9%, and the purity of isooctane is 99.9% and the yield is 99.9%.

Claims

1. A method for separating isopropanol-isooctane azeotropic mixtures in industrial production, characterized in that... The apparatus for implementing this method mainly includes the following components: distillation column 1 (T1), distillation column 2 (T2), condenser 1 (CL1), condenser 2 (CL2), top storage tank 1 (C1), top storage tank 2 (C2), reboiler 1 (H1), reboiler 2 (H2), cooler (COL), and centrifugal pump 1 (P1); the replenished fresh extractant is mixed with the circulating extractant and connected to distillation column 1 (T1) via pipeline; distillation column 1 (T1) is connected to... Distillation column 2 (T2) is connected; distillation column 2 (T2) is connected to distillation column 1 (T1) via pipeline first through cooler (COL) and then through centrifugal pump 1 (P1); condenser 1 (CL1) is connected to distillation column 1 (T1) and top storage tank 1 (C1), and condenser 2 (CL2) is connected to distillation column 2 (T2) and top storage tank 2 (C2); reboiler 1 (H1) and reboiler 2 (H2) are connected to distillation column 1 (T1) and distillation column 2 (T2) respectively; A method for separating isopropanol-isooctane azeotropic mixtures in industrial production using the above-described apparatus includes the following steps: (1) N,N-dimethylacetamide or glycerol is selected as the extractant. The mixture of isopropanol and isooctane feedstocks and the extractant are added to the distillation column 1 (T1) from the bottom part and the top part of the column, respectively. In the distillation column 1 (T1), isopropanol is separated. Part of the bottom stream of the distillation column 1 (T1) is returned to the distillation column 1 (T1) after heat exchange in the reboiler 1 (H1), and part of it is fed into the distillation column 2 (T2). The isopropanol is condensed by the condenser 1 (CL1) and enters the top storage tank 1 (C1). Part of it is refluxed and the other part is high-purity product isopropanol is collected from the top of the distillation column 1 (T1). (2) In distillation column 2 (T2), isooctane is separated. Part of the bottom stream of distillation column 2 (T2) is returned to distillation column 2 (T2) after heat exchange in reboiler 2 (H2), and part is collected as a high-purity extractant. It is first cooled by cooler (COL) and then refluxed to distillation column 1 (T1) by centrifugal pump 1 (P1), thus completing the separation of components. After being condensed by condenser 2 (CL2), isooctane enters the top storage tank 2 (C2). Part of it is refluxed, and the other part is collected from the top of distillation column 2 (T2) as high-purity product isooctane.

2. The method according to claim 1, characterized in that: Distillation column 1 (T1) has 50-70 trays and a temperature of 70-200°C; distillation column 2 (T2) has 50-70 trays and a temperature of 80-220°C.

3. The method according to claim 1, characterized in that: The mass ratio of the feed flow rate of the extractant to the isopropanol-isooctane mixture is 0.1~5.

4. The method according to claim 1, characterized in that: In the isopropanol-isooctane mixture, the mass fraction of isopropanol is 55.1% and the mass fraction of isooctane is 44.9%.

5. The method according to claim 1, characterized in that: The isopropanol recovered from the top of distillation column 1 (T1) has a purity higher than 99.9% and a yield higher than 99.9%; the isooctane recovered from the top of distillation column 2 (T2) has a purity higher than 99.9% and a yield higher than 99.9%.

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