Device for recovering polycarboxylic acid from cyclohexanone wastewater

Abstract

The utility model relates to the technical field of cyclohexanone, and particularly provides a device for recovering polycarboxylic acid from cyclohexanone wastewater, which comprises an extraction tower, an oil phase outlet arranged at the upper part of the extraction tower and connected to a distillation kettle through a pipeline, a gas stripping tower connected to the upper part of the distillation kettle, and a condenser connected to the top of the gas stripping tower through a pipeline, an outlet of the condenser is connected to a polycarboxylic acid storage tank through a pipeline; a water phase outlet is formed in the lower part of the extraction tower and is connected to the water storage tank through a pipeline; and the lower part of the distillation kettle is connected with a high-boiling-point substrate discharge pipeline. By adopting the device, the cyclohexanone wastewater can be subjected to resource utilization, and the device is simple in structure, simple and clear in operation flow and relatively low in energy consumption.

Description

Technical Field

[0001] This utility model belongs to the field of cyclohexanone technology and relates to a device for recovering polycarboxylic acids from cyclohexanone wastewater. Background Technology

[0002] Cyclohexanone is an important chemical raw material with the chemical formula C6H. 10 O, with a molecular weight of 98.14, is a colorless or pale yellow transparent liquid with a strong, pungent odor. It is a major intermediate in the manufacture of nylon, caprolactam, and adipic acid, and is also an important industrial solvent, widely used in paints, organophosphorus pesticides and pesticides, dyes, aviation lubricants, and as a solvent for greases, waxes, and rubber.

[0003] The production of cyclohexanone generates a large amount of wastewater with a pH of 10-12, a water content of about 70%, and a COD as high as 600,000 mg / L. -1 This wastewater mainly consists of inorganic salts, carboxylates, and water. Due to its high salt content, strong alkalinity, and high COD, it presents a significant challenge for wastewater treatment plants.

[0004] Existing wastewater treatment methods generally involve first concentrating the wastewater and then sending it to an incinerator for treatment; or neutralizing the wastewater with acid and then recovering its main components, but the results are minimal. Summary of the Invention

[0005] This invention provides a device for recovering polycarboxylic acids from cyclohexanone wastewater, which can separate high-purity polycarboxylic acids and is simple to operate with low energy consumption.

[0006] The technical solution of this utility model is to provide a device for recovering polycarboxylic acids from cyclohexanone wastewater, including an extraction tower, an oil phase outlet at the top of the extraction tower, which is connected to a distillation kettle via a pipeline, a stripping tower at the top of the distillation kettle, a condenser at the top of the stripping tower via a pipeline, and a polycarboxylic acid storage tank at the outlet of the condenser via a pipeline; an aqueous phase outlet at the bottom of the extraction tower, which is connected to a water storage tank via a pipeline; and a high-boiling-point substrate discharge pipeline at the bottom of the distillation kettle.

[0007] Optionally, the extraction tower is provided with a cyclohexanone wastewater inlet and an extractant inlet, wherein the cyclohexanone wastewater inlet is located at the bottom of the extraction tower and the extractant inlet is located at the top of the extraction tower.

[0008] Optionally, a feed pump is also installed on the pipe connected to the cyclohexanone wastewater inlet.

[0009] Optionally, the pipeline connected to the extractant inlet of the extraction tower includes an alcohol extractant pipeline and an acid adjustment pipeline, which are combined and introduced into the extractant inlet.

[0010] Optionally, the extraction column is equipped with a heat exchange jacket.

[0011] Optionally, the distillation vessel is equipped with a heating jacket.

[0012] Optionally, both the extraction tower and the distillation vessel are made of alloy materials.

[0013] This utility model has the following beneficial effects:

[0014] The apparatus provided by this invention first extracts cyclohexanone wastewater with an extractant to separate the aqueous phase. The oil phase enters a distillation kettle, where a catalyst is added for esterification and distillation. The resulting esterification product is vaporized and separated in a stripping tower, and then condensed in a gas-phase condenser to obtain a mixed polycarboxylic acid ester product. The unvaporized high-boiling-point substrate in the distillation kettle can be collected and used as fuel for combustion. Using this apparatus, efficient recycling of cyclohexanone wastewater can be achieved. Attached Figure Description

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

[0016] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0017] like Figure 1 As shown, this utility model provides an apparatus for recovering polycarboxylic acids from cyclohexanone wastewater, including an extraction tower 1. The upper part of the extraction tower is provided with an oil phase outlet 1-4, which is connected to a distillation kettle 2 via a pipeline. The upper part of the distillation kettle is connected to a stripping tower 3, and the top of the stripping tower is connected to a condenser 4 via a pipeline. The outlet of the condenser is connected to a polycarboxylic acid storage tank via a pipeline. The lower part of the extraction tower is provided with an aqueous phase outlet 1-3, which is connected to a water storage tank 6 via a pipeline. The lower part of the distillation kettle 2 is connected to a high-boiling-point substrate discharge pipeline.

[0018] In some embodiments, the extraction tower 1 is provided with a cyclohexanone wastewater inlet 1-1 and an extractant inlet 1-2, wherein the cyclohexanone wastewater inlet 1-1 is located at the lower part of the extraction tower 1, and the extractant inlet 1-2 is located at the upper part of the extraction tower 1. The extractant used in the extraction tower is an alcohol extractant, such as n-butanol, n-hexanol, n-octanol, or n-decanol, which can not only act as an extractant but also as a raw material to react, and can also azeotropically react with the product to lower the vaporization temperature.

[0019] In some embodiments, a feed pump 5 is also provided on the pipeline connected to the cyclohexanone wastewater inlet 1-1. The cyclohexanone wastewater is fed into the extraction tower through the feed pump.

[0020] In some embodiments, the pipes connected to the extractant inlet 1-2 of the extraction tower 1 include an alcohol extractant pipe and an acid adjustment pipe, which are combined and introduced into the extractant inlet. After the wastewater is added to the extraction tower, acid is added in the extraction tower to adjust the pH of the wastewater to 1-4. The added acid can be sulfuric acid, hydrochloric acid, nitric acid, etc. Different types of sodium salts can be obtained by adding different acids.

[0021] In some embodiments, the extraction tower 1 is provided with heat exchange jackets 1-5, and the temperature is maintained at 25~55°C during extraction.

[0022] In some embodiments, the distillation vessel 2 is equipped with a heating jacket 2-1, and the temperature inside the distillation vessel is controlled at 100~200℃. During the distillation process, a catalyst is added to catalyze the esterification reaction, specifically p-toluenesulfonic acid, vanadium chloride, a strong acid ion exchange resin, sodium bisulfate, etc.

[0023] In some embodiments, the extraction tower and distillation vessel are both made of alloy materials. Hastelloy is preferred as it is better resistant to strong acid corrosion and solvent erosion, especially the strong acid added during acid adjustment. More preferably, the hot water outlet of the heating jacket of the distillation vessel (5) can be connected to the hot water inlet of the heat exchange jacket of the extraction tower, which can reduce energy consumption; the stripping tower, vapor phase condenser and jacket can all be made of ordinary 316L stainless steel, which is resistant to solvent corrosion.

[0024] The above embodiments describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including combining the various technical features in any other way. These simple modifications and combinations should also be considered as the content disclosed by the present invention and all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be determined by the appended claims.

Claims

1. An apparatus for recovering polycarboxylic acids from cyclohexanone wastewater, characterized in that: The extraction tower (1) is provided with an oil phase outlet (1-4) at the top. The oil phase outlet (1-4) is connected to a distillation kettle (2) via a pipeline. The top of the distillation kettle is connected to a stripping tower (3). The top of the stripping tower is connected to a condenser (4) via a pipeline. The outlet of the condenser is connected to a polycarboxylic acid storage tank via a pipeline. The bottom of the extraction tower is provided with an aqueous phase outlet (1-3), which is connected to a water storage tank (6) via a pipeline. The bottom of the distillation kettle (2) is connected to a high-boiling-point substrate discharge pipeline.

2. The apparatus according to claim 1, characterized in that: The extraction tower (1) is provided with a cyclohexanone wastewater inlet (1-1) and an extractant inlet (1-2), wherein the cyclohexanone wastewater inlet (1-1) is located at the lower part of the extraction tower (1) and the extractant inlet (1-2) is located at the upper part of the extraction tower (1).

3. The apparatus according to claim 2, characterized in that: A feed pump (5) is also installed on the pipeline connected to the cyclohexanone wastewater inlet (1-1).

4. The apparatus according to claim 2, characterized in that: The extraction tower (1) has an extractant inlet (1-2) connected to a pipe that includes an alcohol extractant pipe and an acid adjustment pipe, which are introduced into the extractant inlet after they are combined.

5. The apparatus according to any one of claims 1 to 4, characterized in that: The extraction tower (1) is equipped with a heat exchange jacket (1-5).

6. The apparatus according to claim 1, characterized in that: The distillation vessel (2) is equipped with a heating jacket (2-1).

7. The apparatus according to claim 1, characterized in that: Both the extraction tower and the distillation kettle are made of alloy materials.

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