Reaction product separation device and separation method

Abstract

The invention discloses a reaction product separation device and a separation method. The reaction product separation device comprises a circulating tower, a pressure pump, a cooler, a water removal tank, a dehydration tower, a feeding pump and a product tower which are connected in sequence, the product tower is connected with the circulating tower; the circulating tower is also connected with the raw material water separation tank; by adopting an operation method of coupling decantation non-sharp separation rectification and variable pressure crushing azeotropy, the separation device can be used for continuously separating reaction products of a process for preparing methyl acrylate from methyl acetate-formaldehyde in industry, and is simple in process, small in equipment number, simple and convenient to operate and suitable for industrial large-scale separation.

Description

Technical Field

[0001] This application relates to a separation device and method for reaction products, belonging to the field of methyl acrylate separation. Background Technology

[0002] Methyl acrylate is a polymer monomer used in industries such as acrylonitrile synthesis, coating synthesis, and adhesive separation. Currently, the main synthesis routes for methyl acrylate include the acetylene method, acrylonitrile hydrolysis method, and propylene oxidation method. All three involve explosive chemicals and pose certain risks. 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 differ significantly from those of previous processes, exhibiting more azeotropic pairs and smaller boiling point differences. Some researchers have explored the separation and purification process of this process, but these generally involve a large number of devices and complex process flows. Summary of the Invention

[0003] According to one aspect of this application, a reaction product separation device is provided, comprising a circulation tower, a pressurizing pump, a cooler, a dehydration tank, a dehydration tower, a feed pump, and a product tower connected in sequence.

[0004] The product tower is connected to the circulation tower;

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

[0006] The circulating tower, the raw material water distribution tank, the water removal tank, and the dehydration tower are each equipped with a discharge port.

[0007] Another aspect of this application provides a method for separating reaction products using the above-described separation apparatus, 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 the catalytic reaction products of the three.

[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 column. The non-condensable gas is discharged as waste gas.

[0010] The liquid material is fed into a raw material separator to stand and separate into layers, resulting in a first aqueous phase and a first oil phase.

[0011] The first aqueous phase is discharged as waste liquid, and the first oil phase is used as a recycling feedstock.

[0012] The main component of the first aqueous phase is water, and the main components of the first oil phase are methyl acetate and methanol, with the remainder being formaldehyde and a small amount of water.

[0013] S2: The bottom of the circulating tower receives the de-lightened material, which is pressurized by a booster pump, cooled in a cooler, and then sent to a dewatering tank for static stratification to obtain the second aqueous phase and the second oil phase.

[0014] The second aqueous phase is discharged as waste liquid, and the second oil phase is sent to the dehydration tower;

[0015] The second aqueous phase mainly consists of water and methanol;

[0016] The second oil phase consists of methanol, methyl acrylate, and some organic impurities;

[0017] S3: A mixture of methyl acrylate and methanol is separated at the top of the dehydration tower and sent to the product tower after being pressurized by the feed pump for pressurized distillation;

[0018] The waste liquid obtained from the bottom of the dehydration tower is discharged, and the water content of the waste liquid is about 70% to 80%.

[0019] S4: The product column is subjected to pressurized distillation to obtain methyl acrylate product at the bottom of the column;

[0020] Methanol is obtained at the top of the tower, part of which is discharged as a byproduct, and the remainder is sent back to the dehydration tower as recycled methanol.

[0021] The reaction products refer to the reaction products obtained by catalytic reaction of methyl acetate, formaldehyde solution, and methanol. They mainly include water, formaldehyde, methyl acetate, methyl acrylate, methanol, and a small amount of impurities.

[0022] This process separates recyclable methyl acetate, formaldehyde, water, methyl acetate, and a small amount of methanol through a circulation tower, removes excess water through a dehydration tower, and finally separates methanol and methyl acrylate in the product tower.

[0023] 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.

[0024] 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).

[0025] Optionally, the operating temperature of the cooler is 5–60°C.

[0026] Optionally, the operating temperature of the dewatering tank is 5–60°C, and the operating pressure is 1–10 bar (A).

[0027] Optionally, the top temperature of the dehydration tower is 40–150°C, the top pressure is 1–10 bar (A), the theoretical number of plates is 20–80, and the reflux ratio is 1–50.

[0028] Optionally, the product tower has a top temperature of 80–180°C, a top pressure of 2–8 bar (A), a theoretical plate number of 10–80, and a reflux ratio of 1–50.

[0029] The beneficial effects that this application can produce include:

[0030] The reaction product separation device and method provided in this application can be used for the continuous separation of reaction products in the process of producing methyl acrylate from methyl acetate and formaldehyde. The process is simple, requires few pieces of equipment, is easy to operate, and is suitable for industrial-scale separation. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the separation device provided in one embodiment of this application.

[0032] List of components and reference numerals:

[0033] 1. Circulating tower; 2. Raw material water separator; 3. Booster pump; 4. Cooler; 5. Dewatering tank; 6. Dehydration tower; 7. Feed pump; 8. Product tower. Detailed Implementation

[0034] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0035] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially.

[0036] like Figure 1 As shown, according to one embodiment of this application, a reaction product separation device is provided, comprising a circulation tower 1, a pressurizing pump 3, a cooler 4, a dehydration tank 5, a dehydration tower 6, a feed pump 7, and a product tower 8 connected in sequence.

[0037] The product tower 8 is connected to the circulation tower 1;

[0038] The circulating tower 1 is also connected to the raw material distribution tank 2;

[0039] The circulating tower 1, the raw material water separator 2, the water removal tank 5, the dehydration tower 6, and the product tower 8 are each equipped with a discharge port.

[0040] Example 1

[0041] Industrially, the above-mentioned separation device is used for the continuous separation of reaction products in the process of producing methyl acrylate from methyl acetate and formaldehyde:

[0042] Includes the following steps:

[0043] S1: The raw materials are fed into the circulation tower 1. The raw materials mainly include methyl acetate, formaldehyde, methanol and the catalytic reaction products of the three.

[0044] The reaction products refer to the reaction products obtained by catalytic reaction of methyl acetate, formaldehyde solution and methanol, mainly including water, formaldehyde, methyl acetate, methyl acrylate, methanol and a small amount of impurities.

[0045] 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.

[0046] 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 column. The non-condensable gas is discharged as waste gas.

[0047] The liquid phase material is fed into the raw material separator tank 2 and allowed to stand at 0.2 bar (A) and 6°C to separate into layers, resulting in the first aqueous phase and the first oil phase.

[0048] The first aqueous phase is discharged as waste liquid, and the first oil phase is used as a recycling feedstock.

[0049] The first aqueous phase is mainly composed of water, with a molar content of approximately 92%. The first oil phase is mainly composed of 76.9% methyl acetate and 14.9% methanol, with the remainder being formaldehyde and a small amount of water.

[0050] S2: The bottom of the circulating tower 1 receives the de-light material, which is pressurized by the pressurizing pump 3 and cooled to 20°C in the cooler 4. It is then sent to the dewatering tank 5 and allowed to stand and separate under the operating conditions of 20°C and 4.5 bar (A) to obtain the second aqueous phase and the second oil phase.

[0051] The second aqueous phase mainly consists of water and methanol, with methanol accounting for approximately 70.9%.

[0052] The second oil phase consists of methanol, methyl acrylate, and some organic impurities;

[0053] The second aqueous phase is discharged as waste liquid, and the second oil phase is mixed with the circulating methanol from product tower 8 and sent to dehydration tower 6.

[0054] S3: The top temperature of the dehydration tower 6 is 75℃, the top pressure is 1.5 bar (A), it is equipped with 40 theoretical plates, and the reflux ratio is 19. The mixture of methyl acrylate and methanol is separated at the top of the tower through total condensation distillation. After being pressurized by the feed pump 7, it is sent to the product tower 8 for pressurized distillation.

[0055] The bottom of the dehydration tower 6 contains waste liquid with a water content of 77.6% and a methanol content of 20.5%, which is then discharged.

[0056] S4: The product tower 8 has a top temperature of 103℃, a top pressure of 4 bar (A), 60 theoretical plates, and a reflux ratio of 20.2;

[0057] A pressurized distillation operation was performed to obtain methyl acrylate product with a purity of 99.5% at the bottom of the column;

[0058] Methanol with a purity of 99.4% is obtained at the top of the tower, of which 17.5% is discharged as a byproduct and the remainder is sent back to the dehydration tower 6 as recycled methanol.

[0059] 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 device for separating reaction products, characterized in that, It includes a circulating tower, a booster pump, a cooler, a dewatering tank, a dehydration tower, a feed pump, and a product tower connected in sequence; The product tower is connected to the circulation tower; The circulating tower is also connected to the raw material distribution tank; The circulating tower, the raw material water distribution tank, the water removal tank, and the dehydration tower are each equipped with a discharge port.

2. A method for separating reaction products using the separation device described in 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 the catalytic reaction products of the three. Through fractional distillation, non-condensable gas and liquid phase are separated at the top of the column, with the non-condensable gas being discharged as waste gas. The liquid material is fed into a raw material separator to stand and separate into layers, resulting in a first aqueous phase and a first oil phase. The first aqueous phase is discharged as waste liquid, and the first oil phase is used as a recycling feedstock. S2: The bottom of the circulating tower receives the de-lightened material, which is pressurized by a booster pump, cooled in a cooler, and then sent to a dewatering tank for static stratification to obtain the second aqueous phase and the second oil phase. The second aqueous phase is discharged as waste liquid, and the second oil phase is sent to the dehydration tower; S3: A mixture of methyl acrylate and methanol is separated at the top of the dehydration tower and sent to the product tower after being pressurized by the feed pump for pressurized distillation; The waste liquid obtained from the bottom of the dehydration tower is discharged; S4: The product column is subjected to pressurized distillation to obtain methyl acrylate product at the bottom of the column; Methanol is obtained at the top of the tower, part of which is discharged as a byproduct, and the remainder is sent back to the dehydration tower as recycled methanol.

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 operating temperature of the cooler is 5–60°C.

6. The separation method according to claim 2, characterized in that, The operating temperature of the dewatering tank is 5–60°C, and the operating pressure is 1–10 bar (A).

7. The separation method according to claim 2, characterized in that, The dehydration tower has a top temperature of 40–150°C, a top pressure of 1–10 bar (A), a theoretical plate number of 20–80, and a reflux ratio of 1–50.

8. The separation method according to claim 2, characterized in that, The product tower has a top temperature of 80–180°C, a top pressure of 2–8 bar (A), a theoretical plate number of 10–80, and a reflux ratio of 1–50.

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