Ethyl acetate production device based on organic acid catalyst

Abstract

The utility model discloses an organic acid catalyst-based ethyl acetate production device, which comprises an esterification tower, a split-phase tank, an ester phase tank, an ethanol recovery tower, a water phase tank, a dehydrating tower and a refining tower, the upper part of the esterification tower is connected with the split-phase tank through a pipeline, and the lower part of the split-phase tank is connected with the water phase tank through a pipeline; the water phase tank is connected with the ethanol recovery tower through a pipeline, the upper part of the split-phase tank is connected with the ester phase tank through a pipeline, the ester phase tank is connected with the dehydrating tower through a pipeline, the upper part of the dehydrating tower is connected with the water phase tank through a pipeline, the lower part of the dehydrating tower is connected with the refining tower through a pipeline, and the refining tower is connected with the collecting tank through a pipeline. According to the ethyl acetate production device, light component impurities such as diethyl ether are removed through the normal-pressure light component removal tower, the proportion of ethyl acetate is greatly increased and heavy components such as ethyl propionate and propyl acetate are removed by the reduced-pressure heavy component removal tower through reduced-pressure operation and change of the proportion of azeotrope at the top of the tower, and the purity of ethyl acetate is greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of chemical technology, specifically to an ethyl acetate production apparatus based on an organic acid catalyst. Background Technology

[0002] Ethyl acetate, also known as ethyl acetate, is a widely used fine chemical product with excellent solubility and fast drying properties. It is an important organic chemical raw material and an excellent industrial solvent. Currently, industrial production methods for ethyl acetate include esterification, acetaldehyde process, ethanol dehydrogenation, and ethylene-acetic acid addition. Among these, esterification remains an important preparation method. At present, with the rapid development of the global economy and increasingly stringent requirements for environmental protection, benzene solvents, due to their high price and toxicity, can no longer meet the requirements for use as solvents in the production of coatings, inks, and adhesives. Therefore, as a high-end alternative to benzene solvents, the demand for ethyl acetate is increasing year by year.

[0003] In the separation process of the distillation column, the main substances separated are unreacted raw materials ethanol and acetic acid, water produced by the reaction, ethyl acetate as a product, and the azeotrope formed by the above materials and water. Through thermal coupling technology, acetic acid, ethanol and other substances can be effectively separated without increasing the heat source, and finally ethyl acetate with high purity is obtained.

[0004] Patent CN115108910 A discloses a controlled method for synthesizing ethyl acetate via esterification. The method includes the following steps: reacting excess acetic acid with ethanol; pumping the reaction product into a mixing tank and mixing it thoroughly with a dehydrating agent, tetrahydrofuran; pumping the resulting mixture into a distillation column; controlling the temperature and pressure of the distillation column; collecting the tetrahydrofuran and water vapor from the top of the column; collecting the ethyl acetate product from the middle of the distillation column; and collecting excess acetic acid and sulfuric acid catalyst from the bottom of the distillation column for reuse in the esterification column. The vapor from the top of the distillation column and the ethyl acetate product collected from the middle of the distillation column are then exchanged with the reaction raw materials via a heat exchanger. This invention uses concentrated sulfuric acid with a mass concentration of over 80% as the catalyst, which is highly corrosive to equipment, increasing the equipment load. Furthermore, the process requires a large amount of dehydrating agent, resulting in high raw material costs, and the final ethyl acetate product has low purity and high impurity content.

[0005] Patent CN107628946 A discloses a method and apparatus for producing high-purity ethyl acetate using a reactive distillation-membrane coupling system. The method involves acetic acid and ethanol entering a reactive distillation column and undergoing an esterification reaction in the reaction zone to produce ethyl acetate and water. Ethyl acetate and water form a minimum azeotrope. This azeotrope is separated in the rectification section of the reactive distillation column and collected as positive-pressure steam from the top. The remaining water and unreacted excess acetic acid are separated in the stripping section and collected from the bottom of the column. The positive-pressure steam from the azeotrope enters a membrane device, where it is separated by a membrane module. The membrane outlet is ethyl acetate vapor, while the aqueous phase permeates through the membrane module into the negative-pressure side. This invention uses a pervaporation membrane method to remove water from the raw ethanol and the crude ester at the top of the esterification column. This requires additional equipment and pipelines, significantly modifying existing mature production processes and resulting in high costs. Furthermore, the ethyl acetate-ethanol-water ternary azeotrope collected at the top of the column requires further separation and dehydration, making the process complex and resulting in low purity ethyl acetate.

[0006] Therefore, it is particularly important to develop a process for producing high-quality ethyl acetate with high thermal efficiency and low energy consumption. Utility Model Content

[0007] The purpose of this invention is to provide an ethyl acetate production apparatus based on an organic acid catalyst, in order to solve the problems mentioned in the background art, which are that the existing method of removing moisture from raw ethanol and crude ester at the top of the esterification tower using pervaporation membrane method requires the addition of equipment and pipelines, which involves significant modifications to the existing mature production process and results in high costs.

[0008] To achieve the above objectives, this utility model provides the following technical solution: an ethyl acetate production apparatus based on an organic acid catalyst, comprising an esterification tower, a phase separation tank, an ester phase tank, an ethanol recovery tower, an aqueous phase tank, a dehydration tower, and a purification tower. The esterification tower is characterized in that its upper part is connected to the phase separation tank via a pipeline, and its lower part is connected to the aqueous phase tank via a pipeline. The aqueous phase tank is connected to the ethanol recovery tower via a pipeline. The phase separation tank is connected to the ester phase tank via a pipeline, and the ester phase tank is connected to the dehydration tower via a pipeline. The dehydration tower is connected to the aqueous phase tank via a pipeline, and its lower part is connected to the purification tower via a pipeline. The purification tower is connected to a collection tank via a pipeline, and the ethyl acetate in the collection tank serves as the reflux liquid for the esterification tower. The lower part of the purification tower is connected to a crude ester tank via a pipeline, and the crude ester tank is connected to an atmospheric pressure light-light removal tower via a pipeline. The lower part of the atmospheric pressure light-light removal tower is connected to a vacuum de-heavy removal tower via a pipeline, and the upper part of the vacuum de-heavy removal tower is connected to a product tank via a pipeline.

[0009] Preferably, metering pumps are installed on the pipelines connecting the phase separation tank and the esterification tower, and on the collection tank and the esterification tower, respectively, to control the flow rate.

[0010] Preferably, the material at the top of the esterification tower exchanges heat with the material in the ester phase tank via a heat exchanger, providing a heat source for heating the material in the ester phase tank.

[0011] Preferably, the material at the top of the dehydration tower exchanges heat with the raw materials acetic acid and ethanol in the esterification tower through a heat exchanger, providing a heat source for both.

[0012] Preferably, the material at the top of the refining tower exchanges heat with the material in the aqueous phase tank via a heat exchanger, providing it with a heat source.

[0013] Preferably, the material at the top of the depressurization deweighting tower exchanges heat with the material in the crude ester tank to provide a heat source.

[0014] Preferably, a catalyst is added to the inside of the esterification tower. The catalyst is an organic acid catalyst.

[0015] Compared with the prior art, the beneficial effects of this utility model are: the ethyl acetate production apparatus:

[0016] In the synthesis of ethyl acetate, the addition of excess acetic acid to the reaction, under the action of an organic acid catalyst, promotes the forward reaction and significantly improves the conversion rate of ethanol, reducing the difficulty of separating ethanol from the product. This achieves efficient dehydration of ethyl acetate and improves the separation efficiency of the product, while reducing equipment corrosion. Furthermore, by coupling the heat from the vapor phase material at the top of various distillation columns to the reactants and process materials, energy consumption and costs are reduced. The addition of a vacuum stripping column, through vacuum operation, changes the proportion of the azeotrope at the top of the column, significantly increasing the proportion of ethyl acetate and removing heavy components such as ethyl propionate and propyl acetate, greatly improving the purity of ethyl acetate.

[0017] Furthermore, sulfuric acid is typically used as the catalyst for esterification reactions. However, sulfuric acid has several drawbacks, including strong acid corrosion, numerous side reactions, difficulty in handling byproducts, and environmental pollution. In contrast, the catalyst in this invention is an organic acid catalyst, which has lower corrosiveness, requires less dosage, and causes less environmental pollution. Using organic acid as the catalyst reduces the corrosiveness to the equipment. The esterification tower uses a stainless steel reactor, which has a longer service life and better heat transfer than commonly used enamel reactors, thus reducing energy consumption. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall layout structure of this utility model;

[0019] Figure 2 This is a schematic diagram of the connection structure between the esterification tower and the phase separation tank of this utility model;

[0020] Figure 3 This is a schematic diagram of the connection structure between the esterification tower and the collection tank of this utility model.

[0021] In the diagram: 1. Esterification tower; 2. Phase separation tank; 2-1. Ester phase tank; 3. Ethanol recovery tower; 3-1. Aqueous phase tank; 4. Dehydration tower; 5. Purification tower; 5-1. Collection tank; 5-2. Crude ester tank; 6. Atmospheric pressure light phase removal tower; 7. Vacuum pressure heavy phase removal tower; 8. Product tank; 9. Metering pump. Detailed Implementation

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Please see Figure 1-Figure 3 This utility model provides a technical solution: an ethyl acetate production device based on an organic acid catalyst includes an esterification tower 1, a phase separation tank 2, an ester phase tank 2-1, an ethanol recovery tower 3, an aqueous phase tank 3-1, a dehydration tower 4, and a purification tower 5. The upper part of the esterification tower 1 is connected to the phase separation tank 2 via a pipeline, and the lower part of the phase separation tank 2 is connected to the aqueous phase tank 3-1 via a pipeline. The aqueous phase tank 3-1 is connected to the ethanol recovery tower 3 via a pipeline. The upper part of the phase separation tank 2 is connected to the ester phase tank 2-1 via a pipeline, and the ester phase tank 2-1 is connected to the ethanol recovery tower 3 via a pipeline. The system is connected to dehydration tower 4. The upper part of dehydration tower 4 is connected to aqueous phase tank 3-1 via a pipeline, and the lower part of dehydration tower 4 is connected to purification tower 5 via a pipeline. Purification tower 5 is connected to collection tank 5-1 via a pipeline, and ethyl acetate in collection tank 5-1 is used as reflux liquid for esterification tower 1. The lower part of purification tower 5 is connected to crude ester tank 5-2 via a pipeline, and crude ester tank 5-2 is connected to atmospheric pressure light ester removal tower 6 via a pipeline. The lower part of atmospheric pressure light ester removal tower 6 is connected to vacuum pressure heavy ester removal tower 7 via a pipeline, and the upper part of vacuum pressure heavy ester removal tower 7 is connected to product tank 8 via a pipeline.

[0024] Metering pumps 9 are installed on the pipelines connecting phase separation tank 2 to esterification tower 1 and collection tank 5-1 to esterification tower 1, respectively, to control the flow rate. The material at the top of esterification tower 1 exchanges heat with the material in ester phase tank 2-1 through a heat exchanger, providing a heat source for heating the material in ester phase tank 2-1. The material at the top of dehydration tower 4 exchanges heat with the raw materials acetic acid and ethanol in esterification tower 1 through a heat exchanger, providing a heat source for both. The material at the top of purification tower 5 exchanges heat with the material in aqueous phase tank 3-1 through a heat exchanger, providing a heat source for it. The material at the top of vacuum de-weighing tower 7 exchanges heat with the material in crude ester tank 5-2, providing a heat source for it. The catalyst added inside esterification tower 1 is an organic acid catalyst, such as methanesulfonic acid, benzoic acid, p-toluenesulfonic acid, etc.

[0025] In the production of ethyl acetate, this structure first introduces excess acetic acid and ethanol into esterification tower 1 after heat exchange via metering pump 9 and a heat exchanger. An organic acid liquid catalyst is added to prepare for the reaction. Esterification tower 1 is then heated, and the pressure and temperature within the tower are controlled to carry out the esterification reaction. Ethyl acetate, generated water, and trace amounts of ethanol are collected from the top of esterification tower 2-1. The top material, after heat exchange via a heat exchanger, enters phase separation tank 3-1 for separation. The lower aqueous phase material from phase separation tank 3-1 enters ethanol recovery tower 3 for ethanol recovery. The upper ester phase material enters dehydration tower 4 from ester phase tank 2-1 for further aqueous phase separation. Dehydration tower 4... The ester phase material at the top of the column enters the refining tank 5, and the material at the bottom of the column enters the ethanol recovery column 3 via the aqueous phase tank 3-1 for ethanol recovery. In the refining column 5, the material at the top of the column consists of an azeotrope of ethyl acetate and ethanol, which enters the collection tank 5-1 as the reflux liquid at the top of the esterification column 1. The material at the bottom of the column enters the crude ester tank 5-2 for further purification. The crude ethyl acetate in the crude ester tank 5-2 enters the atmospheric pressure light component removal column 6 to remove light components. The material at the bottom of the atmospheric pressure light component removal column 6 enters the vacuum weight removal column 7 to remove heavy components. The vacuum operation changes the azeotrope ratio, which greatly increases the ethyl acetate content at the top of the column. The material at the top of the vacuum weight removal column 7 enters the product tank 8 for collection, and finally, high-purity ethyl acetate product is obtained.

[0026] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An ethyl acetate production apparatus based on an organic acid catalyst, comprising an esterification tower (1), a phase separation tank (2), an ester phase tank (2-1), an ethanol recovery tower (3), an aqueous phase tank (3-1), a dehydration tower (4), and a purification tower (5), characterized in that, The upper part of the esterification tower (1) is connected to the phase separation tank (2) via a pipeline, and the lower part of the phase separation tank (2) is connected to the aqueous phase tank (3-1) via a pipeline. The aqueous phase tank (3-1) is connected to the ethanol recovery tower (3) via a pipeline. The upper part of the phase separation tank (2) is connected to the ester phase tank (2-1) via a pipeline, and the ester phase tank (2-1) is connected to the dehydration tower (4) via a pipeline. The upper part of the dehydration tower (4) is connected to the aqueous phase tank (3-1) via a pipeline, and the lower part of the dehydration tower (4) is connected to the ester phase tank (2-1) via a pipeline. The purification tower (5) is connected to the collection tank (5-1) via a pipeline. Ethyl acetate in the collection tank (5-1) is used as the reflux liquid of the esterification tower (1). The lower part of the purification tower (5) is connected to the crude ester tank (5-2) via a pipeline. The crude ester tank (5-2) is connected to the atmospheric pressure light removal tower (6) via a pipeline. The lower part of the atmospheric pressure light removal tower (6) is connected to the vacuum deweight removal tower (7) via a pipeline. The upper part of the vacuum deweight removal tower (7) is connected to the product tank (8) via a pipeline.

2. The ethyl acetate production apparatus based on an organic acid catalyst according to claim 1, characterized in that: Metering pumps (9) are installed on the pipelines connecting the phase separation tank (2) to the esterification tower (1) and the collection tank (5-1) to the esterification tower (1) to control the flow rate.

3. The ethyl acetate production apparatus based on an organic acid catalyst according to claim 1, characterized in that: The material at the top of the esterification tower (1) exchanges heat with the material in the ester phase tank (2-1) via a heat exchanger, providing a heat source for heating the material in the ester phase tank (2-1).

4. The ethyl acetate production apparatus based on an organic acid catalyst according to claim 1, characterized in that: The material at the top of the dehydration tower (4) exchanges heat with the raw materials acetic acid and ethanol in the esterification tower (1) through a heat exchanger, providing a heat source for both.

5. The ethyl acetate production apparatus based on an organic acid catalyst according to claim 1, characterized in that: The material at the top of the refining tower (5) exchanges heat with the material in the aqueous phase tank (3-1) via a heat exchanger, providing it with a heat source.

6. The ethyl acetate production apparatus based on an organic acid catalyst according to claim 1, characterized in that: The material at the top of the depressurization deweighting tower (7) exchanges heat with the material in the crude ester tank (5-2) to provide a heat source for it.

7. The ethyl acetate production apparatus based on an organic acid catalyst according to claim 1, characterized in that: A catalyst is added to the inside of the esterification tower (1).

8. An ethyl acetate production apparatus based on an organic acid catalyst according to claim 7, characterized in that: The catalyst is an organic acid catalyst.

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