An apparatus and method for separating a product of a aldol condensation reaction

Abstract

The application discloses a separation device and method of a hydroxy aldehyde condensation reaction product, which comprises a circulation tower, a pressurizing pump, a product tower, a cooler, a stabilizing tank and a water remover connected in sequence; the circulation tower is further connected with a raw material water separation tank; the circulation tower, the raw material water separation tank, the product tower, the stabilizing tank and the water remover are respectively provided with discharge outlets; the device and method can be used for continuous production of methyl acetate-methyl formal-methyl acrylate reaction product separation, and are simple in process, few in equipment quantity, easy to operate and suitable for industrial scale production.

Description

Technical Field

[0001] This application relates to a separation device and method for aldol condensation reaction products, belonging to the field of chemical technology. Background Technology

[0002] Methyl acrylate is a polymer monomer used in industries such as acrylonitrile synthesis, coating synthesis, and adhesive production. Currently, the main synthesis routes for methyl acrylate are the acetylene method, acrylonitrile hydrolysis method, and propylene oxidation method. All three involve explosive chemicals and are therefore hazardous.

[0003] Based on the above reasons and the development needs of the coal chemical industry chain, researchers have developed a reaction process for synthesizing methyl acrylate from methyl acetate and formaldehyde. The reaction products of this process are quite different from those of previous processes, with more azeotropic pairs and smaller differences in boiling points. Some researchers have explored the separation and purification process of the reaction products of this process, but they generally involve a large number of equipment and complex process flow, which is not suitable for industrial-scale production. Summary of the Invention

[0004] According to one aspect of this application, a separation device for aldol condensation reaction products is provided, comprising a circulating tower, a pressurizing pump, a product tower, a cooler, a stabilizing tank, and a dehydrator connected in sequence.

[0005] The circulating tower is also connected to the raw material distribution tank;

[0006] The circulating tower, the raw material water distribution tank, the product tower, the stabilizing tank, and the dewatering device are each equipped with a discharge port.

[0007] This application also provides a method for separating reaction products using the above-mentioned separation device, comprising the following steps:

[0008] S1: The raw materials are fed into the circulation tower. The raw materials mainly include methyl acetate, formaldehyde, methanol and their catalytic reaction products.

[0009] Through fractional distillation, a small amount of non-condensable gas containing methyl acetate and formaldehyde, as well as a liquid phase material composed of methanol, methyl acetate, water and formaldehyde, are separated at the top of the circulating column.

[0010] Non-condensable gas is discharged as waste gas, and the liquid phase material is sent to the raw material water separator for static stratification. The first aqueous phase obtained is methanol-containing wastewater, which is discharged as waste liquid.

[0011] The first oil phase contains unreacted methyl acetate, formaldehyde, and some methanol, which are used as a recycled feedstock.

[0012] S2: The bottom of the circulating tower yields a light-weight material, which mainly includes methyl acrylate, methanol, and water. After being pressurized by a booster pump, the material is sent to the product tower.

[0013] S3: The product column is subjected to pressurized distillation to obtain crude methanol at the top of the product column, which is then discharged from the device;

[0014] S4: A mixture of water and methyl acrylate is obtained at the bottom of the product tower. After being cooled by a cooler, it enters a stabilizing tank and is stabilized and separated by gravity decantation to obtain a second aqueous phase and a second oil phase.

[0015] The second aqueous phase, with a water content exceeding 90%, is discharged as wastewater, while the second oil phase, after having trace amounts of water removed by a dehydrator, yields the product methyl acrylate.

[0016] Optionally, the top temperature of the circulating tower is -20 to 60°C, the top pressure is 0 to 3 bar (A), the number of theoretical plates is 10 to 60, and the reflux ratio is 1 to 20.

[0017] Optionally, the operating temperature of the raw material distribution tank is -20 to 60°C, and the operating pressure is 0 to 3 bar (A).

[0018] Optionally, the product tower has a top temperature of 120–220°C, a top pressure of 5–25 bar (A), a theoretical plate number of 30–90, and a reflux ratio of 5–50.

[0019] Optionally, the cooling temperature of the cooler is -20 to 60°C.

[0020] Optionally, the operating temperature of the stabilizer is -20 to 60°C, and the operating pressure is 1 to 5 bar (A).

[0021] The beneficial effects that this application can produce include:

[0022] The separation device and method for aldol condensation reaction products provided in this application can be used for the continuous production of methyl acetate-formaldehyde to methyl acrylate reaction products. The process is simple, requires few pieces of equipment, is easy to operate, and is suitable for industrial-scale production. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a separation device for aldol condensation reaction products provided in one embodiment of this application.

[0024] List of components and reference numerals:

[0025] 1. Circulating tower; 2. Raw material water separator; 3. Booster pump; 4. Product tower; 5. Cooler; 6. Stabilizer; 7. Dewatering device. Detailed Implementation

[0026] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0027] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially.

[0028] like Figure 1 As shown, according to one embodiment of this application, a separation device for aldol condensation reaction products is provided, comprising a circulation tower 1, a pressure pump 3, a product tower 4, a cooler 5, a stabilizer 6, and a dehydrator 7 connected in sequence.

[0029] The circulating tower 1 is also connected to the raw material distribution tank 2;

[0030] The circulating tower 1, the raw material water distribution tank 2, the product tower 4, the stabilizing tank 6, and the water separator 7 are each equipped with a discharge port.

[0031] Example 1

[0032] The method for separating reaction products using the above-mentioned separation device includes the following steps:

[0033] S1: The raw materials are fed into the circulation tower 1. The raw materials mainly include methyl acetate, formaldehyde, methanol and their catalytic reaction products.

[0034] The top temperature of the circulating column 1 is 5℃, the operating pressure is 0.2 bar (A), and it is equipped with 36 theoretical plates and a reflux ratio of 11.2.

[0035] Through fractional distillation, a small amount of non-condensable gas containing methyl acetate and formaldehyde, as well as a liquid phase material composed of methanol, methyl acetate, water and formaldehyde, are separated at the top of the circulating tower 1.

[0036] Non-condensable gas is discharged as waste gas. The liquid phase material is sent to raw material water separator 2 and allowed to stand and separate at 0.2 bar (A) and 6°C. The first aqueous phase is methanol-containing wastewater and is discharged as waste liquid. The first oil phase contains unreacted methyl acetate, formaldehyde and some methanol and is used as recycled raw material.

[0037] S2: The bottom of the circulating tower 1 is obtained with light-removed material, which mainly includes methyl acrylate, methanol, and water. After being pressurized by the pressurizing pump 3, it is sent to the product tower 4.

[0038] S3: The product column 4 is subjected to pressurized distillation. The top temperature of the product column 4 is 161°C, the operating pressure is 18 bar (A), there are 64 theoretical plates, and the reflux ratio is 19.2.

[0039] Crude methanol with a methanol concentration of 96.3% is obtained at the top of product column 4 and discharged from the device;

[0040] S4: A mixture of water and methyl acrylate is obtained at the bottom of the product tower 4. After being cooled to 10°C by the cooler 5, it enters the stabilizing tank 6 and is stabilized and separated by gravity decantation under a pressure of 2 bar (A) to obtain the second aqueous phase and the second oil phase.

[0041] The second aqueous phase with a water content of 95.1% is discharged as wastewater, and the second oil phase is dehydrated by a dewatering device 7 to remove trace amounts of water, resulting in a methyl acrylate product with a purity of 99.5%.

[0042] The above description is only a part of the embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A separation device for aldol condensation reaction products, characterized in that, It includes a circulating tower, a booster pump, a product tower, a cooler, a stabilizer, and a dewatering device connected in sequence; The circulating tower is also connected to the raw material distribution tank; The circulating tower, the raw material water distribution tank, the product tower, the stabilizing tank, and the dewatering device are each equipped with a discharge port.

2. A method for separation using the separation device according to claim 1, characterized in that, Includes the following steps: S1: The raw materials are fed into the circulation tower. The raw materials mainly include methyl acetate, formaldehyde, methanol and their catalytic reaction products. Through fractional distillation, non-condensable gas and liquid phase are separated at the top of the circulating tower. The non-condensable gas is discharged as waste gas, and the liquid phase is sent to the raw material separator for settling and stratification. The first aqueous phase is discharged as waste liquid, and the first oil phase is used as a circulating raw material. S2: The bottom of the circulating tower yields a light-weight material, which mainly includes methyl acrylate, methanol, and water. After being pressurized by a booster pump, the material is sent to the product tower. S3: The product column is subjected to pressurized distillation to obtain crude methanol at the top of the product column, which is then discharged from the device; S4: A mixture of water and methyl acrylate is obtained at the bottom of the product tower. After being cooled by a cooler, it enters a stabilizing tank and is stabilized and separated by gravity decantation to obtain a second aqueous phase and a second oil phase. The second aqueous phase is discharged as wastewater, and the second oil phase is dehydrated by a dewatering device to remove trace amounts of water, yielding the product methyl acrylate.

3. The separation method according to claim 2, characterized in that, The circulating tower has a top temperature of -20 to 60°C, a top pressure of 0 to 3 bar (A), a theoretical plate number of 10 to 60, and a reflux ratio of 1 to 20.

4. The separation method according to claim 2, characterized in that, The operating temperature of the raw material water separator is -20 to 60°C, and the operating pressure is 0 to 3 bar (A).

5. The separation method according to claim 2, characterized in that, The product tower has a top temperature of 120–220°C, a top pressure of 5–25 bar (A), a theoretical plate number of 30–90, and a reflux ratio of 5–50.

6. The separation method according to claim 2, characterized in that, The cooling temperature of the cooler is -20 to 60°C.

7. The separation method according to claim 2, characterized in that, The operating temperature of the stabilizer is -20 to 60°C, and the operating pressure is 1 to 5 bar (A).

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