A continuous reaction-separation apparatus for the preparation of 3-pentanone by condensation of propionic acid

Abstract

The utility model discloses a kind of propionic acid condensation preparation 3-pentanone's continuous reaction separation device, belong to chemical technology field.The device mainly includes column tube fixed bed reactor, flash tank, liquid separation tank one, crude separation tower, liquid separation tank two, 3-pentanone refining tower and stripping column, and it is characterized by: using flash tank to remove the large amount of CO2 of reaction generation, reduce subsequent system load, avoid incondensable gas interference separation;Through crude separation tower, unreacted propionic acid is accurately separated and recycled, and raw material utilization is improved;And through the collaborative operation of 3-pentanone refining tower and stripping column, cooperate liquid separation tank two circulation loop, water-3-pentanone azeotrope is broken down efficiently, the synthesis of high-purity 3-pentanone is realized, the whole device is continuous integration degree, separation efficiency is high, energy consumption is low, suitable for industrial continuous production.

Description

Technical Field

[0001] This utility model relates to the field of chemical technology, specifically to a continuous reaction separation device for the preparation of 3-pentanone by propionic acid condensation. Background Technology

[0002] 3-Pentanone is an important organic chemical intermediate, and propionic acid condensation is one of its main synthetic routes. However, existing technologies for the preparation of 3-pentanone by propionic acid condensation face several technical challenges. First, the reaction generates a large amount of CO2 gas, which not only increases the burden on the equipment but also interferes with subsequent separation processes. Second, 3-pentanone forms an azeotrope with water (the azeotropic composition is approximately 30 wt% water), which is difficult to separate effectively using conventional distillation methods and requires the introduction of a third component (entrainer), complicating the process and posing a risk of product contamination. Furthermore, failure to efficiently recover unreacted propionic acid leads to raw material waste. Therefore, existing technologies suffer from high energy consumption, complex processes, and low recovery rates. To overcome these shortcomings, there is an urgent need to develop a device specifically designed for the propionic acid ketone reaction, capable of effectively removing CO2, efficiently recovering propionic acid, and breaking down the azeotropic system, ultimately achieving high-purity, low-energy production of 3-pentanone.

[0003] Therefore, to address the above problems, a continuous reaction separation device for the preparation of 3-pentanone by propionic acid condensation is proposed. This device removes the CO2 generated by the reaction through a flash tank, separates and recovers unreacted propionic acid using a coarse separation tower, and efficiently breaks the azeotropic reaction between water and 3-pentanone, thereby achieving the synthesis of high-purity 3-pentanone. The entire device has a high degree of continuous integration, high separation efficiency, and low energy consumption, making it suitable for industrial continuous production. Utility Model Content

[0004] This utility model relates to the field of chemical technology, specifically disclosing a continuous reaction separation device for the preparation of 3-pentanone by propionic acid condensation. It includes a propionic acid storage tank 1, a water storage tank 2, a raw material preheater 5, a tubular fixed-bed reactor 6, a flash tank 8, a first separator 9, a coarse separator 10, a second separator 12, a 3-pentanone refining tower 13, and a stripping tower 14. Its features are: the propionic acid storage tank 1 and the water storage tank 2 are respectively connected to the inlet of the raw material preheater 5 via pipelines; the outlet of the raw material preheater 5 is connected to the inlet of the tubular fixed-bed reactor 6; the outlet of the tubular fixed-bed reactor 6 is connected to the inlet of the flash tank 8 via a pipeline; the top of the flash tank 8 is provided with a CO2 emission port; the bottom of the flash tank 8 is connected to the inlet of the first separator 9; the top of the first separator 9 has an organic phase outlet. The outlet of the crude fractionation tower 10 is connected to the feed inlet of the crude fractionation tower 10, and the outlet of the bottom of the separator 9 is connected to the feed inlet of the stripping tower 14. The top outlet of the crude fractionation tower 10 is connected to the feed inlet of the separator 12, and the bottom outlet of the crude fractionation tower 10 is connected to the propionic acid storage tank 1 via a pipeline. The top outlet of the separator 12 is connected to the feed inlet of the 3-pentanone refining tower 13, and the bottom outlet of the separator 12 is connected to the feed inlet of the stripping tower 14. The top outlet of the 3-pentanone refining tower 13 and the top outlet of the stripping tower 14 are connected to the feed inlet of the separator 12 via pipelines, forming a circulation loop. The bottom of the 3-pentanone refining tower 13 has a product 3-pentanone outlet, and the bottom of the stripping tower 14 has a wastewater outlet.

[0005] Specifically, a feed pump 3 is connected between the propionic acid storage tank 1 and the raw material preheater 5.

[0006] Specifically, a feed pump 4 is connected between the water storage tank 2 and the raw material preheater 5.

[0007] Specifically, a water-cooled heat exchanger 7 is connected between the tubular fixed-bed reactor 6 and the flash tank 8.

[0008] Specifically, a water-cooled heat exchanger 11 is connected between the bottom of the coarse separation tower 10 and the liquid separator 12.

[0009] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0010] (1) Efficient CO2 removal: By setting up a flash tank, the CO2 generated by the reaction is removed in time, avoiding interference of non-condensable gases with subsequent distillation operations and reducing the load on the separation equipment;

[0011] (2) Efficient raw material recycling: By precisely controlling the operating parameters of the coarse separation tower, unreacted propionic acid is efficiently separated and returned to the storage tank for recycling, thereby improving the utilization rate of raw materials;

[0012] (3) Efficiently breaking the azeotrope between water and 3-pentanone: Through the coordinated operation of the 3-pentanone purification tower and the stripping tower, and the organic-aqueous phase dual circulation loop formed by the two separators, the azeotrope between water and 3-pentanone can be efficiently broken without the addition of a third component;

[0013] (4) Continuous integration: The entire device realizes continuous operation of the entire process of reaction, CO2 removal, crude separation, azeotropic cracking and purification, with a high degree of automation, which is suitable for large-scale industrial production;

[0014] (5) Reduced energy consumption: Compared with traditional batch operation and the method of adding a third component to destroy azeotropic distillation, the energy consumption of this device is reduced and the operating cost is significantly reduced. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] The reference numerals and names in the figure are as follows:

[0017] 1. Propionic acid storage tank; 2. Water storage tank; 3. Feed pump one; 4. Feed pump two; 5. Raw material preheater; 6. Tubular fixed bed reactor; 7. Water-cooled heat exchanger one; 8. Flash tank; 9. Separator one; 10. Crude separator; 11. Water-cooled heat exchanger two; 12. Separator two; 13. 3-Pentanone refining tower; 14. Stripping tower. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example

[0019] As attached Figure 1 As shown,

[0020] A continuous reaction separation device for the preparation of 3-pentanone by propionic acid condensation includes a propionic acid storage tank 1, a water storage tank 2, a raw material preheater 5, a tubular fixed-bed reactor 6, a flash tank 8, a first separator 9, a coarse separator 10, a second separator 12, a 3-pentanone purification tower 13, and a stripping tower 14. Work process:

[0021] Propionic acid and water are fed to the raw material preheater 5 via feed pump 3 and feed pump 4 respectively in a molar ratio of 1:0.5. After being preheated to 200-250°C, they enter the tubular fixed bed reactor 6.

[0022] The tubular fixed-bed reactor 6 is filled with an Al-Mn-O composite oxide catalyst. The reaction temperature is 410℃, the pressure is 1.0MPa, the propionic acid conversion rate reaches 75-85%, and the 3-pentanone selectivity is ≥90%.

[0023] Reaction equation: 2CH3CH2COOH → CH3CH2COCH2CH3 + CO2 + H2O

[0024] The reaction mixture is cooled to 100°C by water-cooled heat exchanger 7 and then enters flash tank 8. The operating pressure is 0.2 MPa. CO2 is discharged from the top of flash tank 8, and the mixed solution enters separator 9 from the bottom of flash tank 8. The CO2 removal rate is ≥99%.

[0025] The material from the bottom of flash evaporator 8 enters separator 9 for preliminary separation. The organic phase (3-pentanone, unreacted propionic acid, and a small amount of water) enters coarse separation column 10, with a bottom temperature of 140℃ and a top temperature of 100℃, and a theoretical plate count of 20. Unreacted propionic acid (purity >98%) is collected from the bottom of coarse separation column 10 and recycled to propionic acid storage tank 1. The mixture at the top of the column (3-pentanone and 3-pentanone-water azeotrope) is condensed by water-cooled heat exchanger 11 and then enters separator 12.

[0026] (5) The organic phase collected from the top of separator 12 enters 3-pentanone refining tower 13 (theoretical plate number 15, tower bottom temperature 102℃, tower top temperature 82℃). The 3-pentanone-water azeotrope is refluxed from the top of 3-pentanone refining tower 13 back to separator 12. High-purity 3-pentanone product (purity 99.96%, yield 92%) is collected from the bottom of 3-pentanone refining tower 13. The aqueous phase collected from the bottom of separator 9 and separator 12 enters stripping tower 14 (theoretical plate number 10). Through stripping, a small amount of pentanone-water azeotrope dissolved in water is distilled off from the top of stripping tower 14 and recycled back to separator 12. Wastewater (organic content less than 0.5%) is collected from the bottom of stripping tower 14. Example

[0027] The difference from Example 1 is that the molar ratio of propionic acid to water was adjusted to 1:1, the reaction temperature was 400℃, the propionic acid conversion rate was 82%, the purity of the 3-pentanone product was 99.7%, and the yield was 94%. Example

[0028] The difference from Example 1 is that the catalyst was replaced with a Mn-Ce composite oxide, the reaction temperature was 400℃, the pressure was 0.8 MPa, the conversion rate was 78%, the selectivity was 92%, and the product purity was 99.95%.

[0029] The above description is merely a preferred embodiment of this utility model. In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front," "rear," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

Claims

1. A continuous reaction separation device for the preparation of 3-pentanone by propionic acid condensation, comprising a propionic acid storage tank (1), a water storage tank (2), a raw material preheater (5), a tubular fixed-bed reactor (6), a flash tank (8), a first separator (9), a coarse separator (10), a second separator (12), a 3-pentanone refining tower (13), and a stripping tower (14), characterized in that: The propionic acid storage tank (1) and water storage tank (2) are respectively connected to the inlet of the raw material preheater (5) via pipelines; the outlet of the raw material preheater (5) is connected to the inlet of the tubular fixed bed reactor (6); the outlet of the tubular fixed bed reactor (6) is connected to the inlet of the flash tank (8) via pipelines, the flash tank (8) has a CO2 emission port at the top, and the bottom of the flash tank (8) is connected to the inlet of the separator (9); the organic phase outlet at the top of the separator (9) is connected to the inlet of the coarse separation tower (10), and the aqueous phase outlet at the bottom of the separator (9) is connected to the inlet of the stripping tower (14); The top outlet of the coarse separation tower (10) is connected to the inlet of the second separator (12), and the bottom outlet of the coarse separation tower (10) is connected to the propionic acid storage tank (1) through a pipeline; the top outlet of the second separator (12) is connected to the inlet of the 3-pentanone refining tower (13), and the bottom outlet of the second separator (12) is connected to the inlet of the stripping tower (14). The top outlet of the 3-pentanone refining tower (13) and the top outlet of the stripping tower (14) are connected to the inlet of the second separator (12) through a pipeline to form a circulation loop. The bottom of the 3-pentanone refining tower (13) is provided with a product 3-pentanone outlet, and the bottom of the stripping tower (14) is provided with a wastewater outlet.

2. The continuous reaction separation apparatus for the preparation of 3-pentanone by propionic acid condensation according to claim 1, characterized in that: A feed pump (3) is connected between the propionic acid storage tank (1) and the raw material preheater (5).

3. The continuous reaction separation apparatus for the preparation of 3-pentanone by propionic acid condensation according to claim 1, characterized in that: A feed pump 2 (4) is connected between the water storage tank (2) and the raw material preheater (5).

4. The continuous reaction separation apparatus for the preparation of 3-pentanone by propionic acid condensation according to claim 1, characterized in that: A water-cooled heat exchanger (7) is connected between the tubular fixed bed reactor (6) and the flash tank (8).

5. The continuous reaction separation apparatus for the preparation of 3-pentanone by propionic acid condensation according to claim 1, characterized in that: A water-cooled heat exchanger (11) is connected between the bottom of the coarse separation tower (10) and the liquid separation tank (12).

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