Refining device and refining method of polymerization product and application

Abstract

The invention discloses a refining device and method for a polymerization product and application. The refining device comprises an aldehyde removal tower, a dehydration tower, a water separation tank, a light component removal tower, a byproduct tower and a product tower. According to the present invention, the reaction product obtained through the ethylene glycol dehydration condensation reaction contains water, acetaldehyde, diethylene glycol, 1, 4-dioxane, 2-methyldioxocyclopentane and other components, and has characteristics of complex components and coexistence of multiple azeotropic pairs, and the invention provides the sequential rectification method by introducing the azeotropic breaking component according to the composition, therefore, a diethylene glycol product with high purity and byproducts of acetaldehyde and 1, 4-dioxane are separated, the process is continuous and easy to operate, and the method has industrial feasibility.

Description

Technical Field

[0001] The present application relates to a polymer product refining device and refining method and application, and belongs to the field of chemical technology. Background Art

[0002] Diethylene glycol, also known as diethylene glycol acetal, is commonly used as an organic solvent, antifreeze, desiccant, softener and plasticizer. It is widely used in daily chemical industries such as oils, resins, nitrocellulose, dyes and equipment manufacturing industries. At present, all diethylene glycol products are by-products of ethylene oxide hydration to produce ethylene glycol, generally accounting for 8% to 10% of ethylene glycol production. In recent years, with the continuous development of my country's polyester industry and the continuous increase in the requirements of advanced equipment manufacturing industry, the demand for diethylene glycol has also continued to increase. Therefore, the production attribute of diethylene glycol as a by-product has severely restricted the increase in production capacity, and the exploration of emerging diethylene glycol synthesis routes is particularly urgent.

[0003] Ethylene glycol dehydration condensation is an ideal production process for diethylene glycol. This application proposes a product / by-product separation and purification process for the reaction products of the diethylene glycol synthesis method. The process is simple and can achieve continuous production, which is suitable for industrial continuous production operations. Summary of the invention

[0004] According to one aspect of the present application, a polymer product refining device is provided, the refining device comprising: an aldehyde removal tower, a dehydration tower, a water separation tank, a light removal tower, a by-product tower, and a product tower;

[0005] The aldehyde removal tower is connected to the dehydration tower, the bottom of the dehydration tower is connected to the lightness removal tower, the lightness removal tower is connected to the by-product tower, and the by-product tower is connected to the product tower;

[0006] The top of the dehydration tower is connected to the water separation tank, and the discharge port of the water separation tank is connected to the dehydration tower;

[0007] The dehydration tower is provided with a raw material inlet;

[0008] The product tower is provided with an outlet for the refined product of the polymerization product.

[0009] Optionally, the reflux ratio of the aldehyde removal tower is 230-350.

[0010] Optionally, the number of theoretical plates of the aldehyde removal tower is 10 to 80.

[0011] Optionally, the top temperature of the aldehyde removal tower is 10-100° C., and the operating pressure is 100-500 kPaA.

[0012] Optionally, the reflux ratio of the dehydration tower is 0.1-30.

[0013] Optionally, the dehydration tower has 10 to 80 theoretical plates.

[0014] Optionally, the top temperature of the dehydration tower is 40-100° C., and the operating pressure is 100-500 kPaA.

[0015] Optionally, the operating temperature of the water separation tank (3) is 40-100°C, and the operating pressure is 100-500 kPaA.

[0016] Optionally, the reflux ratio of the lightness removal tower (4) is 150-350.

[0017] Optionally, the lightness removal tower (4) has a theoretical plate number of 10 to 80.

[0018] Optionally, the top temperature of the lightness removal tower (4) is 50-150° C., and the operating pressure is 100-300 kPaA.

[0019] Optionally, the reflux ratio of the by-product tower is 0.01-5.

[0020] Optionally, the by-product tower has 10 to 60 theoretical plates.

[0021] Optionally, the top temperature of the by-product tower is 10-100° C., and the operating pressure is 1-100 kPaA.

[0022] Optionally, the reflux ratio of the product tower is 3-15.

[0023] Optionally, the product tower has 10 to 60 theoretical plates.

[0024] Optionally, the top temperature of the product tower is 80-150° C., and the operating pressure is 1-100 kPaA.

[0025] According to another aspect of the present application, a method for refining a polymer product is provided, the method comprising:

[0026] The polymerized product is introduced into a reaction device as a raw material, and distilled to obtain a refined product of the polymerized product;

[0027] The reaction device is selected from the above-mentioned polymerization product purification device.

[0028] Optionally, the polymer product comprises the following components in terms of molar composition:

[0029]

[0030] Optionally, the refining method comprises the following steps:

[0031] (1) The polymer product is fed into a dealdehyde tower as a raw material, and distilled to obtain by-product acetaldehyde at the top of the dealdehyde tower;

[0032] (2) the acetaldehyde-free mixture at the bottom of the aldehyde removal tower enters a dehydration tower, is mixed with an azeotrope-breaker, and is distilled. The dehydrated material obtained at the bottom of the dehydration tower enters a light-removal tower. The bottom product of the light-removal tower enters a by-product tower for distillation. The bottom product of the by-product tower enters a product tower for distillation.

[0033] 1,4-dioxane is obtained at the top of the by-product tower; crude ethylene glycol is obtained at the top of the product tower, and diethylene glycol is obtained at the bottom of the tower;

[0034] (3) A mixture containing water and azeotrope breaking agent is obtained at the top of the dehydration tower and enters a water separation tank for separation and separation to obtain waste water and dehydrated azeotrope breaking agent. The dehydrated azeotrope breaking agent enters the dehydration tower again.

[0035] Optionally, the method for refining the polymer product comprises the following steps:

[0036] 1) The aldehyde removal tower 1 is provided with a separation raw material inlet, and adopts a micro-positive pressure full condensation distillation to obtain by-product acetaldehyde at the top of the tower, and separate the acetaldehyde removal mixture at the bottom of the tower;

[0037] 2) The bottom material of the aldehyde removal tower 1 is mixed with the azeotrope breaking agent and passed to the dehydration tower 2. The dehydration tower 2 adopts atmospheric distillation to obtain a mixture of water and the azeotrope breaking agent at the top of the tower, and the dehydrated material is obtained at the bottom of the tower;

[0038] 3) The top of the dehydration tower 2 is connected to the water separator 3, and the materials are separated in the water separator 3 to obtain waste water and dehydrated azeotrope breaking agent, and the azeotrope breaking agent outlet is connected to the dehydration tower 2 inlet;

[0039] 4) The bottom of the dehydration tower 2 is connected to the light impurity removal tower 4, the top of the light impurity removal tower 4 has a light impurity extraction interface and pipeline, and the bottom of the tower is connected to the by-product tower 5;

[0040] 5) The top of the by-product tower 5 is provided with a by-product 1,4-dioxane extraction interface and pipeline, and the bottom of the tower is connected to the product tower 6.

[0041] 6) The unreacted crude ethylene glycol raw material is taken out from the top of the product tower 6, and the diethylene glycol product is obtained at the bottom of the tower.

[0042] Optionally, the azeotrope-breaker is selected from at least one of benzene, xylene, acetone and cyclohexane.

[0043] According to another aspect of the present application, there is provided an application of the above-mentioned polymerization product purification device in the separation and purification of ethylene glycol dehydration polymerization reaction products.

[0044] In the present application, a method for refining a polymer product is provided, using a mixed product obtained by a dehydration condensation reaction of ethylene glycol as a raw material (the molar composition of the raw material is 0.1-10% ethylene glycol, 15-32% diethylene glycol, 5-20% 1,4-dioxane, 0.01-0.5% acetaldehyde, 0.01-0.5% 2-methyldioxolane, and 25-70% water), and the refining device comprises the following parts: a dealdehyde tower 1, a dehydration tower 2, a water separation tank 3, a light removal tower 4, a by-product tower 5, and a product tower 6. The condensation reaction product is first sent to the dealdehyde tower 1, and the by-product acetaldehyde is separated at the top of the tower, and the mixture at the bottom of the tower is sent to the dehydration tower 2. A dehydration tower 2 is introduced into the upper part of the dehydration tower 2, and an oil-water two-phase mixture is obtained at the top of the tower, and the mixture is placed in the water separation tank 3 for stratification to obtain waste water and a dehydration agent for recycling. The dehydrated mixture at the bottom of the dehydration tower 2 is sent to the light removal tower 4, and light impurity oil is obtained at the top of the tower. The dehydrogenated mixture obtained at the bottom of the tower is sent to the by-product tower 5, and the re-produced 1,4-dioxane is separated at the top of the tower. The ethylene glycol / diethylene glycol mixture obtained at the bottom of the tower is sent to the product tower 6. The unreacted ethylene glycol is obtained at the top of the product tower 6, and the diethylene glycol product is obtained at the bottom of the tower.

[0045] The beneficial effects of this application include:

[0046] The method for refining the polymerization product provided in the present application contains water, acetaldehyde, diethylene glycol, 1,4-dioxane, 2-methyldioxolane and other components in the reaction product obtained by the dehydration condensation reaction of ethylene glycol, and has the characteristics of complex components and coexistence of multiple azeotropic pairs. The present invention provides a sequential distillation method for introducing azeotropic breaking components for the composition, thereby separating the diethylene glycol product with higher purity and the acetaldehyde and 1,4-dioxane by-products, and the process is continuous and easy to operate, and has industrial feasibility. It can be used for the separation and purification of the ethylene glycol dehydration polymerization reaction product, with a continuous process and a simple process, and is suitable for industrial continuous production operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the structure of the refining device for the polymer product in Example 1 of the present application.

[0048] in:

[0049] 1. Aldehyde removal tower; 2. Dehydration tower; 3. Water separation tank; 4. Lightness removal tower; 5. By-product tower; 6. Product tower. DETAILED DESCRIPTION

[0050] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0051] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0052] Example 1

[0053] like Figure 1 The figure shows a refining device for a polymerization product, which comprises: a dealdehyde tower 1, a dehydration tower 2, a water separation tank 3, a light-removing tower 4, a by-product tower 5, and a product tower 6; the dealdehyde tower 1 is connected to the dehydration tower 2, the bottom of the dehydration tower 2 is connected to the light-removing tower 4, the light-removing tower 4 is connected to the by-product tower 5, and the by-product tower 5 is connected to the product tower 6; the top of the dehydration tower 2 is connected to the water separation tank 3, and the discharge port of the water separation tank 3 is connected to the dehydration tower 2; the dehydration tower 2 is provided with a raw material inlet; the product tower 6 is provided with an outlet for a refined product of the polymerization product.

[0054] Example 2

[0055] The condensation reaction product (molar composition of ethylene glycol 2.1%, diethylene glycol 27.9%, 1,4-dioxane 13.8%, acetaldehyde 0.16%, 2-methyldioxolane 0.16%, water 55.9%) is first sent to the dealdehyde tower 1, the tower top pressure of the dealdehyde tower 1 is 150kPaA, the tower top temperature is 32°C, 30 theoretical plates are set, the reflux ratio is 250, the by-product acetaldehyde is separated at the top of the tower, and the mixture at the bottom of the dealdehyde tower 1 is sent to the dehydration tower 2. The top pressure of the dehydration tower 2 is 110kPaA, the tower top temperature of the dehydration tower 2 is 56°C, 50 theoretical plates are set, the reflux ratio is 10, and the azeotroping agent cyclohexane is introduced into the upper part. After separation, a two-phase mixture of cyclohexane and water is obtained at the top of the dehydration tower 2, which is sent to the water separation tank 3, and is placed at 56°C and 110kPaA pressure for stratification to obtain waste water and cyclohexane for recycling. The dehydrated mixture at the bottom of dehydration tower 2 is sent to light removal tower 4, the top pressure of light removal tower 4 is 110kPaA, the top temperature is 84°C, 50 theoretical plates are set, the reflux ratio is 290, and the light impurity oil containing 2-methyldioxolane is obtained at the top of light removal tower 4. The dehydrogenated mixture obtained at the bottom of light removal tower 4 is sent to by-product tower 5, the top pressure of by-product tower 5 is 10kPaA, the top temperature is 39°C, 25 theoretical plates are set, the reflux ratio is 0.8, and the by-product 1,4-dioxane with a molar concentration of 99.9% is separated at the top of the tower. The ethylene glycol / diethylene glycol mixture obtained at the bottom of the tower is sent to product tower 6. The top pressure of product tower 6 is 5kPaA, the top temperature is 117°C, 35 theoretical plates are set, the reflux ratio is 8.6, unreacted ethylene glycol is obtained at the top of product tower 6, and a diethylene glycol product with a molar concentration of 99.96% is obtained at the bottom of product tower 6.

[0056] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A polymer product purification device, characterized in that: The refining device comprises: an aldehyde removal tower (1), a dehydration tower (2), a water separation tank (3), a lightness removal tower (4), a by-product tower (5), and a product tower (6); The aldehyde removal tower (1) is connected to the dehydration tower (2), the bottom of the dehydration tower (2) is connected to the lightness removal tower (4), the lightness removal tower (4) is connected to the by-product tower (5), and the by-product tower (5) is connected to the product tower (6); The top of the dehydration tower (2) is connected to the water separation tank (3), and the discharge port of the water separation tank (3) is connected to the dehydration tower (2); The dehydration tower (2) is provided with a raw material inlet; The product tower (6) is provided with an outlet for the refined product of the polymerization product.

2. The refining device according to claim 1, characterized in that: The reflux ratio of the aldehyde removal tower (1) is 230-350; Preferably, the number of theoretical plates of the aldehyde removal tower (1) is 10 to 80; Preferably, the top temperature of the aldehyde removal tower (1) is 10-100° C., and the operating pressure is 100-500 kPaA.

3. The refining device according to claim 1, characterized in that: The reflux ratio of the dehydration tower (2) is 0.1 to 30; Preferably, the number of theoretical plates of the dehydration tower (2) is 10 to 80; Preferably, the top temperature of the dehydration tower (2) is 40-100° C., and the operating pressure is 100-500 kPaA.

4. The refining device according to claim 1, characterized in that: The operating temperature of the water separation tank (3) is 40-100°C, and the operating pressure is 100-500kPaA; Preferably, the reflux ratio of the lightness removal tower (4) is 150 to 350; Preferably, the number of theoretical plates of the lightness removal tower (4) is 10 to 80; Preferably, the top temperature of the lightness removal tower (4) is 50-150° C., and the operating pressure is 100-300 kPaA.

5. The refining device according to claim 1, characterized in that: The reflux ratio of the by-product tower (5) is 0.01 to 5; Preferably, the number of theoretical plates of the by-product tower (5) is 10 to 60; Preferably, the top temperature of the by-product tower (5) is 10-100°C, and the operating pressure is 1-100 kPaA.

6. The refining device according to claim 1, characterized in that: The reflux ratio of the product tower (6) is 3 to 15; Preferably, the product column (6) has a theoretical plate number of 10 to 60; Preferably, the top temperature of the product tower (6) is 80-150° C., and the operating pressure is 1-100 kPaA.

7. A method for purifying a polymer product, characterized in that: The refining method comprises: The polymerized product is introduced into a reaction device as a raw material, and distilled to obtain a refined product of the polymerized product; The reaction device is selected from the device for refining the polymer product according to any one of claims 1 to 6.

8. The refining method according to claim 7, characterized in that: According to the molar composition, the polymer product includes the following components:

9. The refining method according to claim 7, characterized in that: The refining method comprises the following steps: (1) The polymer product is fed into a dealdehyde tower as a raw material, and distilled to obtain by-product acetaldehyde at the top of the dealdehyde tower; (2) the acetaldehyde-free mixture at the bottom of the aldehyde removal tower enters a dehydration tower, is mixed with an azeotrope-breaker, and is distilled. The dehydrated material obtained at the bottom of the dehydration tower enters a light-removal tower. The bottom product of the light-removal tower enters a by-product tower for distillation. The bottom product of the by-product tower enters a product tower for distillation. 1,4-dioxane is obtained at the top of the by-product tower; crude ethylene glycol is obtained at the top of the product tower, and diethylene glycol is obtained at the bottom of the tower; (3) A mixture containing water and azeotrope breaking agent is obtained at the top of the dehydration tower and enters a water separation tank, where the mixture is separated into layers to obtain waste water and dehydrated azeotrope breaking agent, which then enters the dehydration tower again; Preferably, the azeotrope breaker is selected from at least one of benzene, xylene, acetone and cyclohexane.

10. Use of the polymerization product purification device according to any one of claims 1 to 6 in the separation and purification of ethylene glycol dehydration polymerization reaction products.

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