New process for extracting neopentyl glycol from residual liquid

Abstract

According to the novel process for extracting the neopentyl glycol from the residual liquid, the catalyst is added into the residual liquid at the bottom of the tower after the neopentyl glycol rectification system, under the action of the catalyst, the hydroxyl pivalate neopentyl glycol ester in the residual liquid is hydrolyzed, and then the neopentyl glycol is recovered through rectification, so that the resource waste is reduced. Besides, the crude neopentyl glycol solution is changed into a gas phase to enter a rectification system for further purification under the pressure of-10 to-5 kPa and the temperature of 180-195 DEG C in the cracking tower, and the high-purity neopentyl glycol is extracted from the tower top and sent to a product tank, so that the aim of recovering the neopentyl glycol is fulfilled. According to the method and the system, neopentyl glycol in discharged gas can be effectively recovered, the yield of neopentyl glycol is increased, the production cost is reduced, and the production benefit is increased.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of neopentyl glycol production and relates to a new process for extracting neopentyl glycol from residual liquid. BACKGROUND

[0002] Neopentyl glycol is a white crystalline solid with hygroscopicity and is mainly used for producing unsaturated resin, oil-free alkyd resin, plasticizer of polyurethane foam plastic and elastomer, surfactant and the like and is widely applied.

[0003] The crude neopentyl glycol solution generated in the production process of neopentyl glycol needs to be removed of impurities in a cracking tower and a heavy-removing tower to obtain neopentyl glycol aqueous solution, and then is further treated to obtain neopentyl glycol product. When the crude neopentyl glycol solution is removed of waste water in the cracking tower, ester substances are generated, which mainly include neopentyl glycol isobutyrate 0.2-0.5%, neopentyl glycol formate 0.1-0.2%, neopentyl glycol hydroxy pivalate 0.4-0.5% and the like. The generation of the ester substances seriously causes the waste of neopentyl glycol resources. In addition, increasing the temperature of the original rectification system will simultaneously generate new ester substances, which causes the decrease of product purity and causes the waste of resources. SUMMARY

[0004] The application aims to provide a new process for extracting neopentyl glycol from residual liquid to solve the problem of waste of neopentyl glycol resources in the prior production method.

[0005] To achieve the above-mentioned purpose, the application adopts the following technical scheme: The application provides a new process for extracting neopentyl glycol from residual liquid, which comprises: the ester substances in the heavy component are decomposed by adding a catalyst, the catalyst comprises potassium hydroxide or barium hydroxide and an active substance, the ester substances comprise one or more of neopentyl glycol isobutyrate, neopentyl glycol formate and neopentyl glycol hydroxy pivalate, the ester substances are continuously decomposed by cracking, and the finally produced substance is separated and recovered from the neopentyl glycol cracked out of the heavy-removing tower.

[0006] Preferably, the feeding mass ratio of the heavy component solution to the catalyst is 1: (0.4-0.5).

[0007] Preferably, the concentration of the catalyst is 8%.

[0008] Preferably, the pressure in the cracking tower is -80--65kpa, and the bottom temperature of the tower is 200-210℃.

[0009] Preferably, the components of the catalyst are potassium hydroxide, hydrogen peroxide and barium hydroxide.

[0010] Preferably, the mass ratio of the catalyst is 75:15:15.

[0011] The application provides a new process for extracting neopentyl glycol from residual liquid, comprising a cracking tower and a heavy component removal tower in communication, wherein the cracking tower is fed by a metering pump connected with a heavy component tank and a catalyst storage tank through different pipelines.

[0012] Preferably, a feed flow meter is arranged between the heavy component tank and the cracking tower.

[0013] Preferably, a metering pump, a metering pump outlet flow meter and a metering pump outlet regulating valve are arranged in sequence between the catalyst storage tank and the cracking tower, and the cracking tower feed flow meter is located between the metering pump outlet regulating valve and the cracking tower.

[0014] Preferably, a cracking tower bottom pump and a heavy component removal tower feed flow meter are arranged in sequence between the cracking tower and the heavy component removal tower.

[0015] The application has the following beneficial effects: (1) After the heavy components enter the cracking tower, catalyst is added to the cracking tower to hydrolyze the ester substances in the heavy components, thereby generating neopentyl glycol and other salt substances, and increasing the content of neopentyl glycol in the heavy components.

[0016] (2) Under the conditions of a pressure of -80--65 kPa and a temperature of 200-210℃, the ester substances such as neopentyl glycol formate and neopentyl glycol isobutyrate in the heavy components are hydrolyzed to generate organic salts such as potassium formate, neopentyl glycol and potassium isobutyrate, further increasing the content of neopentyl glycol in the heavy components, and recovering neopentyl glycol through the heavy component removal tower, thereby achieving the purpose of recovering neopentyl glycol.

[0017] (3) The method and system can effectively recover neopentyl glycol in the effluent, reduce the waste of neopentyl glycol, reduce production cost and increase production benefit. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The structure schematic diagram of the system of the new process for extracting neopentyl glycol from residual liquid provided by the embodiment of the application is shown in the figure. 1-heavy component tank, 2-catalyst storage tank, 3-metering pump, 4-cracking tower bottom pump, 5-cracking tower, 6-heavy component removal tower, 8-cracking tower feed flow meter, 9-metering pump outlet flow meter, 10-metering pump outlet regulating valve, 11-heavy component removal tower feed flow meter. DETAILED DESCRIPTION

[0019] The technical solutions of the application are further explained and described below through specific embodiments.

[0020] The application provides a new process for extracting neopentyl glycol from residual liquid. The system comprises a cracking tower 5 and a heavy component removal tower 6 connected in sequence. The feed of the cracking tower 5 is connected with a heavy component tank 1 and a catalyst storage tank 2 through two different pipes by means of a metering pump. As shown in the accompanying drawings, the heavy component tank 1 is a device for placing a heavy component solution, and the catalyst storage tank 2 is a device for placing a catalyst. The heavy component tank 1 and the catalyst storage tank 2 are connected with the cracking tower 5 through two different pipes respectively, so that the heavy component solution and the catalyst are mixed in the cracking tower and circulated through a cracking tower bottom pump, thereby completing the process of cracking reaction. Figure 1

[0021] In the embodiment of the application, a cracking tower feed flowmeter 8 is arranged between the heavy component tank 1 and the cracking tower 5, so as to control the flow of the heavy component solution into the cracking tower 5. A metering pump 3, a metering pump outlet flowmeter 9 and a metering pump outlet regulating valve 10 are arranged in sequence between the catalyst storage tank 2 and the cracking tower 5, and the cracking tower feed flowmeter 8 is located between the metering pump outlet regulating valve 10 and the cracking tower 5. Under the action of the metering pump outlet regulating valve 10 and the metering pump 3, the catalyst storage tank 2 introduces the catalyst into the cracking tower 5 through the metering pump outlet flowmeter 9, so as to control the addition amount of the catalyst, and thus the heavy component solution is in the cracking environment of ester substances when the heavy component solution and the catalyst are at the bottom of the cracking tower 5. In the embodiment of the application, the ester substances are produced during the rectification of neopentyl glycol, and include one or more of neopentyl glycol isobutyrate, neopentyl glycol formate and neopentyl glycol hydroxy pivalate.

[0022] The catalyst in the catalyst storage tank 2 in the embodiment of the application is configured according to a certain mass ratio. A pressure regulating device is arranged at the top of the cracking tower 5, so as to maintain the pressure inside the cracking tower 5 at-80--65kpa. A temperature control device is further arranged at the bottom of the cracking tower 5, so as to maintain the temperature at the bottom of the cracking tower 5 at 200-210℃.

[0023] In the embodiment of the application, a cracking tower bottom pump 4 and a heavy component removal tower feed flowmeter 11 are arranged in sequence between the cracking tower 5 and the heavy component removal tower 6. The mass ratio (1:0.4) of the feed of the heavy component solution and the catalyst is controlled by controlling the temperature at the bottom of the cracking tower, so as to facilitate the adjustment of the flow rate of the materials in the heavy component tank 1 and the catalyst storage tank 2. After the heavy component solution is cracked in the cracking tower 5, the heavy component solution is discharged into the heavy component removal tower 6 through the cracking tower bottom pump 4 and the heavy component removal tower feed flowmeter 11, thereby completing the recovery of neopentyl glycol.

[0024] ​The application also provides a new process for extracting neopentyl glycol from residual liquid, which comprises: adding a catalyst into a cracking tower 5 through a catalyst storage tank 2 when a heavy component solution enters the cracking tower, so that the heavy component solution is in an alkaline environment, the heavy component is further cracked to generate organic salts and crude neopentyl glycol, and then the neopentyl glycol is recovered. In addition, when the heavy component is in the alkaline environment, ester substances such as neopentyl glycol formate and neopentyl glycol isobutyrate can be hydrolyzed to generate organic salts such as potassium formate, neopentyl glycol and potassium isobutyrate, so as to increase the content of neopentyl glycol in the heavy component solution and improve the recovery rate of the heavy component. The organic salts generated by hydrolysis of the ester substances are removed through a heavy component removal tower 6.

[0025] In the embodiment of the application, the catalyst is composed of potassium hydroxide, hydrogen peroxide and barium hydroxide, and the mass ratio is 75:15:15. The mass ratio of the heavy component solution to the catalyst is 1: (0.4-0.5) to control the heavy component solution at the bottom of the cracking tower 5 to be in the hydrolysis environment of the ester substances. After the catalyst is added, the content of neopentyl glycol in the heavy component is increased from 28% to more than 75%, and the content of neopentyl glycol hydroxy pivalate is reduced from 30-45% to 0, which greatly improves the recovery rate of the crude neopentyl glycol solution. After the organic salt substances are removed through the heavy component removal tower 6, the neopentyl glycol is recovered at the top of the heavy component removal tower.

[0026] In the embodiment of the application, the pressure in the cracking tower 5 is-80--65kpa, and the bottom temperature is 200-210℃.

[0027] The technical solutions of the application are further explained and described below through specific embodiments.

[0028] Embodiment 1 The embodiment of the application provides a new process for extracting neopentyl glycol from residual liquid, which comprises: adding a mixed catalyst into a cracking tower according to the mass ratio of the heavy component solution to the catalyst being 1:0.3 when the heavy component solution enters the cracking tower, wherein the catalyst is potassium hydroxide: hydrogen peroxide: barium hydroxide with a mass ratio of 45:15:15, so that the heavy component solution is in the hydrolysis environment of the ester substances. After the catalyst is mixed with the heavy component solution, the mixture is reacted in the cracking tower with a pressure of-85kpa and a temperature of 210℃. After the reaction is completed, the mixture is introduced into a heavy component removal tower to remove organic salts and unreacted ester substances, and a neopentyl glycol solution is recovered.

[0029] Embodiment 2 The embodiment of the present application provides a new process for extracting neopentyl glycol from residual liquid, which comprises the following steps: when the heavy component solution enters a cracking tower, mixed catalyst is added into the cracking tower according to a feed mass ratio of the heavy component solution to the catalyst being 1:0.4, wherein the catalyst is potassium hydroxide, hydrogen peroxide and barium hydroxide, and the mass ratio is 75:15:15, so that the heavy component solution is in an ester hydrolysis environment. After the catalyst is mixed with the heavy component solution, the mixture is reacted in the cracking tower under the conditions of a pressure of-85 kpa and a temperature of 210 DEG C. After the reaction is completed, the mixture is introduced into a heavy component removal tower to remove organic salts and unreacted ester substances, and a neopentyl glycol solution is recovered.

[0030] Example 3 The embodiment of the present application provides a new process for extracting neopentyl glycol from residual liquid, which comprises the following steps: when the heavy component solution enters a cracking tower, mixed catalyst is added into the cracking tower according to a feed mass ratio of the heavy component solution to the catalyst being 1:0.5, wherein the catalyst is composed of potassium hydroxide, hydrogen peroxide and barium hydroxide, and the mass ratio is 75:15:15, so that the heavy component solution is in an ester hydrolysis environment. After the catalyst is mixed with the heavy component solution, the mixture is reacted in the cracking tower under the conditions of a pressure of-85 kpa and a temperature of 210 DEG C. After the reaction is completed, the mixture is introduced into a heavy component removal tower to remove organic salts and unreacted ester substances, and a neopentyl glycol solution is recovered.

[0031] Comparative Example 1 The embodiment of the present application provides a new process for extracting neopentyl glycol from residual liquid, which comprises the following steps: when the heavy component solution enters a cracking tower, mixed catalyst is added into the cracking tower according to a feed mass ratio of the heavy component solution to the catalyst being 1:0.5, wherein the catalyst is composed of potassium hydroxide, hydrogen peroxide and barium hydroxide, and the mass ratio is 75:15:15, so that the heavy component solution is in an ester hydrolysis environment. After the catalyst is mixed with the heavy component solution, the mixture is reacted in the cracking tower under the conditions of a pressure of-85 kpa and a temperature of 210 DEG C. After the reaction is completed, the mixture is introduced into a heavy component removal tower to remove organic salts and unreacted ester substances, and a neopentyl glycol solution is recovered.

[0032] In the embodiment 1-3 and the comparative example 1, the content of each impurity in the heavy component solution is shown in Table 1.

[0033] Table 1: Content of each impurity in the heavy component solution in the embodiment 1-3 and the comparative example 1 As shown in Table 1, after the method provided in the embodiments of the present application is used, the content of isobutyric acid neopentyl glycol ester and hydroxy pivalic acid neopentyl glycol ester and other ester substances is greatly reduced, the content of neopentyl glycol in the heavy component solution is increased from 28% to above 74%, the product quality is improved, and the purpose of saving is achieved.

[0034] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Various modifications and changes can be made by those skilled in the art based on the spirit and principles of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A novel process for extracting neopentyl glycol from residual liquid, characterized in that, include: During the purification of neopentyl glycol, a solution of some heavy components and some esters is generated. A catalyst is added to the heavy component solution, wherein the catalyst includes potassium hydroxide or barium hydroxide and an active substance, and the esters include one or more of neopentyl glycol isobutyrate, neopentyl glycol formate, and neopentyl glycol hydroxypentanoate.

2. The novel process for extracting neopentyl glycol from residual liquid according to claim 1, characterized in that, The feed mass ratio of the heavy component solution to the catalyst is 1:(0.4-0.5).

3. A novel process for extracting neopentyl glycol from residual liquid according to claim 2, characterized in that, The feed mass ratio of the heavy component solution to the catalyst is 1:0.

5.

4. A novel process for extracting neopentyl glycol from residual liquid according to claim 1, characterized in that, The pressure inside the pyrolysis tower is -80 to 65 kPa, and the temperature at the bottom of the tower is 200 to 210 °C.

5. A novel process for extracting neopentyl glycol from residual liquid according to claim 1, characterized in that, The catalyst has a mass ratio of 75:15:15, and its components are potassium hydroxide: hydrogen peroxide: barium hydroxide.

6. A novel process for extracting neopentyl glycol from residual liquid, characterized in that, It includes a connected cracking tower (5) and a de-heavy tower (6), wherein the cracking tower (5) is fed with feed and catalyst respectively by a pump.

7. A novel process for extracting neopentyl glycol from residual liquid according to claim 6, characterized in that, A feed flow meter (8) is provided between the catalyst tank (1) and the cracking tower (5).

8. A novel process for extracting neopentyl glycol from residual liquid according to claim 7, characterized in that, A metering pump (3), a metering pump outlet flow meter (9), and a metering pump outlet regulating valve (10) are sequentially provided between the recombinant fraction storage tank (2) and the pyrolysis (5), and the pyrolysis feed flow meter (8) is located between the metering pump outlet regulating valve (10) and the pyrolysis (5).

9. A novel process for extracting neopentyl glycol from residual liquid according to claim 6, characterized in that, A pyrolysis bottom pump (4) and a de-weighting tower feed flow meter (11) are sequentially installed between the pyrolysis tower (5) and the de-weighting tower (6).

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