Treatment device for extracting crude phenol from phenol-containing distillate oil and realizing zero discharge of wastewater

Abstract

The utility model relates to a treatment device for extracting crude phenol from phenol-containing distillate oil and realizing zero discharge of wastewater, which comprises an alkali preparation tank, a top extraction pipeline of a crystallizer is connected with the alkali preparation tank, a dilute alkali outlet of the alkali preparation tank is connected with the upper part of an alkaline washing tower and the upper part of an adsorption tower, the lower part of the alkaline washing tower is connected with a phenol-containing distillate oil pipeline, and the bottom of the alkaline washing tower is connected with the upper part of a stripping tower through a pipeline; a sodium salt solution outlet of the decomposition tower is connected with the upper part of the extraction tower through a pipeline; the lower part of the extraction tower is connected with an extraction agent supply pipeline; a top extraction pipeline of the extraction tower is connected with the upper part of the regeneration tower; a bottom extraction pipeline of the extraction tower is connected with the top of the adsorption tower; a top extraction pipeline of the regeneration tower is connected with an extraction agent supply pipeline, a bottom extraction pipeline of the adsorption tower is connected with the upper part of the complexing tank, a regeneration outlet of the adsorption tower is connected with the decomposition tower, and the complexing tank is connected with the crystallizer. The device provided by the utility model can realize extraction of crude phenol from carbolic oil and zero discharge of wastewater, and thoroughly solves the environmental protection problem in the process of acid-base phenol extraction from coal tar.

Description

Technical Field

[0001] This utility model relates to the technical field of coal chemical industry and comprehensive utilization of coal tar, and in particular to a device for extracting crude phenol from phenol-containing distillate oil and treating wastewater with zero discharge. Background Technology

[0002] Coal tar is a black or dark brown viscous liquid with a pungent odor, produced during the pyrolysis of coal. It is an important raw material in coal chemical industry, possessing rich chemical components and wide applications. The coal tar industry should continue to develop to contribute to both the economy and the environment. However, the production of coal tar generates large amounts of pollutants such as waste gas, wastewater, and waste residue, which can have a certain impact on the environment and ecology. Therefore, effective environmental protection measures need to be taken during the production and use of coal tar to reduce pollutant emissions and protect the environment and ecology.

[0003] Phenol is an important chemical raw material. In recent years, with the development of downstream phenol products, the demand for phenol has been increasing year by year. Currently, domestic supply cannot meet demand, and imports are necessary every year. In coal tar, 86% of phenol is mainly concentrated in phenol oil, naphthalene oil, and phenol-containing fractions of wash oil. With the extension of the downstream industrial chain, the market demand for crude phenol is increasing year by year. At present, the acid-base method is one of the main ways to extract crude phenol from coal tar. This process has the advantages of high efficiency, high yield, fast reaction, and low cost. However, the acid-base method for extracting phenol generates saline and phenol-containing wastewater, which can cause environmental harm. Utility Model Content

[0004] This invention aims to address the shortcomings of existing technologies by providing a device for extracting crude phenol from phenol-containing distillate oil and treating wastewater with zero discharge.

[0005] To achieve the above objectives, this utility model adopts the following technical solution:

[0006] A device for extracting crude phenol from phenolic distillate oil and treating wastewater with zero discharge includes an alkali washing tower, a stripping tower, a decomposition tower, an extraction tower, a regeneration tower, an adsorption tower, a complexing tank, an alkali mixing tank, and a crystallizer.

[0007] The alkali mixing tank is connected to a solid alkali supply pipeline. The top outlet pipeline of the crystallizer is connected to the alkali mixing tank. The dilute alkali outlet of the alkali mixing tank is connected to the upper part of the alkali washing tower and the upper part of the adsorption tower via pipelines. The lower part of the alkali washing tower is connected to a phenol-containing distillate oil pipeline. The bottom of the alkali washing tower is connected to the upper part of the stripping tower via a pipeline. The bottom of the stripping tower is connected to the decomposition tower via a pipeline. The decomposition tower is connected to an acidic substance supply pipeline. The sodium salt solution outlet of the decomposition tower is connected to the upper part of the extraction tower via a pipeline. The lower part of the extraction tower is connected to an extractant supply pipeline. The top outlet pipeline of the extraction tower is connected to the upper part of the regeneration tower. The bottom outlet pipeline of the extraction tower is connected to the top of the adsorption tower. The top outlet pipeline of the regeneration tower is connected to the extractant supply pipeline. The bottom outlet pipeline of the adsorption tower is connected to the upper part of the complexing tank. The regeneration outlet of the adsorption tower is connected to the decomposition tower. The complexing tank is connected to a complexing agent pipeline and is connected to the crystallizer.

[0008] Alkali washing towers can be operated as a single unit or in cascades, with the number of stages ranging from 1 to 6.

[0009] The extraction tower can be operated as a single unit or in cascades of multiple units, with the number of stages ranging from 1 to 6.

[0010] The adsorption tower is filled with adsorption packing material.

[0011] The beneficial effects of this utility model are: this utility model can realize the extraction of crude phenol from phenol oil and zero discharge of wastewater, and completely solve the environmental protection problem in the process of acid-base extraction of phenol from coal tar. Attached Figure Description

[0012] Figure 1 This is a connection diagram of the processing device in this utility model;

[0013] In the diagram: 1-Alkali washing tower; 2-Stripping tower; 3-Decomposition tower; 4-Extraction tower; 5-Regeneration tower; 6-Adsorption tower; 7-Complexing tank; 8-Alkali preparation tank; 9-Crystallizer; 10-Solid alkali supply pipeline; 11-Phenolic distillate oil pipeline; 12-Acidic substance supply pipeline; 13-Extractant supply pipeline; 14-Complexing agent pipeline;

[0014] The following will describe in detail the embodiments of this utility model with reference to the accompanying drawings. Detailed Implementation

[0015] The principles and features of this utility model are described below with reference to the accompanying drawings. The embodiments described are for illustrative purposes only and are not intended to limit the scope of this utility model. The utility model is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of this utility model will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this utility model.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0018] Equipment for extracting crude phenol from phenolic distillate oils and for zero-discharge treatment of wastewater, such as... Figure 1 As shown, it includes an alkali washing tower 1, a stripping tower 2, a decomposition tower 3, an extraction tower 4, a regeneration tower 5, an adsorption tower 6, a complexing tank 7, an alkali mixing tank 8, and a crystallizer 9.

[0019] The alkali mixing tank 8 is connected to a solid alkali supply pipeline 10. The top outlet pipeline of the crystallizer 9 is connected to the alkali mixing tank 8. The dilute alkali outlet of the alkali mixing tank 8 is connected to the upper part of the alkali washing tower 1 and the upper part of the adsorption tower 6 via pipelines. The lower part of the alkali washing tower 1 is connected to a phenol-containing distillate oil pipeline 11. The bottom of the alkali washing tower 1 is connected to the upper part of the stripping tower 2 via a pipeline. The bottom of the stripping tower 2 is connected to the decomposition tower 3 via a pipeline. The decomposition tower 3 is connected to an acidic substance supply pipeline 12. The sodium salt solution outlet of the decomposition tower 3 is connected to a pipeline... The line is connected to the upper part of the extraction tower 4, the lower part of the extraction tower 4 is connected to the extractant supply line 13, the top outlet line of the extraction tower 4 is connected to the upper part of the regeneration tower 5, the bottom outlet line of the extraction tower 4 is connected to the top of the adsorption tower 6, the top outlet line of the regeneration tower 5 is connected to the extractant supply line 13, the bottom outlet line of the adsorption tower 6 is connected to the upper part of the complexing tank 7, the regeneration outlet of the adsorption tower 6 is connected to the decomposition tower 3, the complexing tank 7 is connected to the complexing agent line 14, and the complexing tank 7 is connected to the crystallizer 9.

[0020] Alkali washing tower 1 can be operated as a single unit or in cascade operation, with the number of stages ranging from 1 to 6.

[0021] Extraction column 4 can be operated as a single unit or in cascade mode, and the number of stages in extraction column 4 is 1-6.

[0022] The adsorption tower 6 is filled with adsorption packing material.

[0023] A method for extracting crude phenol from phenolic distillate oil and treating wastewater with zero discharge, utilizing the aforementioned apparatus for extracting crude phenol from phenolic distillate oil and treating wastewater with zero discharge, comprises the following specific steps:

[0024] S1. Preparation of dilute alkali:

[0025] Dilute alkali is prepared in alkali preparation tank 8 using desalination wastewater from subsequent crystallizer 9 and solid alkali. The concentration of dilute alkali is 2%-50%, the operating temperature is 25℃-100℃, and the pressure is 0MPa(g)-0.6MPa(g).

[0026] Dilute alkali is used as a raw material for phenol oil washing, adsorption and regeneration.

[0027] S2, Phenolic oil and alkali washing:

[0028] The phenol-containing distillate oil enters the alkaline washing tower 1 from the bottom and comes into countercurrent contact with the dilute alkali entering from the top of the alkaline washing tower 1. The volume ratio of the dilute alkali to the phenol-containing distillate oil is 1:100. The operating temperature is 25℃-100℃ and the operating pressure is 0MPa(g)-0.6MPa(g). The phenol-containing distillate oil consists of phenolic oil and neutral oil. The phenolic oil reacts with the dilute alkali to form a sodium phenolate solution. The remaining distillate is dephenolized oil. The sodium phenolate solution has a higher specific gravity than the dephenolized oil and is insoluble in the dephenolized oil. Therefore, the dephenolized oil is collected at the top of the alkaline washing tower 1 and sold as a by-product. The sodium phenolate solution is collected at the bottom of the alkaline washing tower 1 and is used as a raw material for the production of crude phenol.

[0029] S3, stripping and impurity removal:

[0030] The sodium phenolate solution contains a small amount of neutral oil. This neutral oil impurity is removed by stripping to obtain a purified sodium phenolate solution free of neutral oil impurities. The sodium phenolate solution enters from the top of stripping tower 2. The bottom of stripping tower 2 is heated indirectly or directly, with an operating temperature of 100℃-180℃ and an operating pressure of 0MPa(g)-0.6MPa(g). The neutral oil vaporizes in the bottom of the tower and rises to the top. After condensation and cooling at the top, the liquid neutral oil is collected and sold as a byproduct. The purified sodium phenolate solution, free of neutral oil, is collected from the bottom of the tower and sent to decomposition tower 3 after being cooled by a cooler.

[0031] S4. Acidification and decomposition:

[0032] Sodium phenolate can decompose with substances stronger than phenol. A stronger acid than phenol is added to decomposition tower 3, causing the sodium phenolate to decompose. The concentration of the acid is 10%-100%, and the volume ratio of the acid to the sodium phenolate solution is 1:1000. The operating temperature is 100℃-180℃, and the operating pressure is 0MPa(g)-0.6MPa(g). After the reaction is complete, crude phenol and a sodium salt solution (sodium carbonate or sodium sulfate) are produced. Because the crude phenol is relatively small and insoluble in the sodium salt solution, it separates into layers. The upper layer is crude phenol, which is sold as a product. The lower layer is the sodium salt solution, which contains a small amount of phenolic substances. The sodium salt solution enters extraction tower 4 for extraction and phenol removal.

[0033] The acidic substance is carbon dioxide, sulfuric acid, or a combination of carbon dioxide and sulfuric acid in any proportion.

[0034] S5, Extraction and Phenol Removal:

[0035] The sodium salt solution contains phenolic compounds and requires phenol removal treatment. The sodium salt solution enters from the top of extraction tower 4 and comes into countercurrent contact with the extractant entering from the bottom of extraction tower 4. The volume ratio of extractant to sodium salt solution is 1:100. The operating temperature is 100℃-180℃, and the operating pressure is 0MPa(g)-0.6MPa(g). The phenol-containing extractant is collected from the top of extraction tower 4 and used as the feed for regeneration tower 5. The phenol removal wastewater is collected from the bottom of extraction tower 4 and used as the feed for adsorption tower 6.

[0036] The extractant is one or any combination of toluene, xylene, methyl isobutyl ketone, methyl tert-butyl ketone, diisopropyl ether, methyl tert-amyl ether, butyl acetate, sec-butyl acetate, dimethyl carbonate, 2-ethylhexyl phosphate-2-ethylhexyl ester, methyl diethanolamine, N,N-bis(1-methylheptyl)acetamide, dihexylpropanolamine, sulfolane, and petroleum ether.

[0037] S6. Extractant regeneration:

[0038] The phenol-containing extractant enters from the top of regeneration tower 5. The extractant is regenerated by stripping, with an operating temperature of 100℃-200℃ and an operating pressure of -0.1MPa(g)-0.6MPa(g). The extractant with a lower boiling point is heated and vaporized in the bottom of the tower, separating from the phenolic substances with a higher boiling point. The vaporized extractant gas rises to the top of the tower and is collected at the top of regeneration tower 5. The extractant is returned to extraction tower 4 for recycling. Crude phenol is collected at the bottom of regeneration tower 5 and sold as waste product.

[0039] S7, Adsorption and phenol removal:

[0040] The phenol-removing wastewater enters from the top of the adsorption tower 6, which is filled with adsorption packing. As the phenol-removing wastewater passes through the adsorption packing, the phenolic substances in the wastewater are adsorbed by the adsorption packing. The adsorbed phenol-removing wastewater is collected at the bottom of the adsorption tower 6 and used as feed for the complexing tank 7. When the adsorption packing is saturated, dilute alkali is introduced into the adsorption tower 6. The dilute alkali reacts with the phenol on the surface of the adsorption packing to produce sodium phenolate solution. The sodium phenolate solution is collected at the bottom of the adsorption column and sent to the decomposition tower 3. After the sodium phenolate is completely discharged, the regenerated adsorption column is recycled. The operating temperature is 25℃-100℃ and the operating pressure is 0MPa(g)-0.6MPa(g).

[0041] The adsorption filler is one or any combination of activated carbon, resin, coke, semi-coke, and membrane.

[0042] S8, Complexation and Impurity Removal:

[0043] The phenol-removing wastewater enters from the top of the complexing tank 7. A complexing agent is added to the complexing tank 7. The complexing agent is a dilute solution of 0.1%-30%. The mass ratio of the complexing agent to the phenol-removing wastewater is 1:1000. The operating temperature is 25℃-100℃ and the operating pressure is 0MPa(g)-0.6MPa(g). The colorimetric substances in the phenol-removing wastewater react with the complexing agent to form a precipitate. The complexed precipitate is separated from the bottom of the complexing tank 7, and decolorized wastewater is obtained. The decolorized wastewater is used as the feed for the crystallizer 9.

[0044] Complexing agents are compounds containing any one or more combinations of sodium ions, calcium ions or molecules, magnesium ions or molecules, copper ions or molecules, iron ions or molecules, aluminum ions or molecules, zinc ions or molecules, thiosulfate, carbonate, sulfate, hydroxyl groups, and carbon chain groups.

[0045] S9, Crystallization Desalination:

[0046] The decolorized wastewater is sent to crystallizer 9, which uses heating or freezing methods for desalination. The crystallization desalination operation temperature is -25℃ to 200℃, and the operation pressure is -0.1MPa(g) to 0.6MPa(g). The crystallization desalination method is one or any combination of single-effect evaporation, multi-effect evaporation, MVR, and freeze crystallization. Finally, inorganic salts are obtained at the bottom of crystallizer 9, and circulating water is obtained at the top of crystallizer 9. The circulating water is returned to the alkali preparation tank 8 and used as raw material for dilute alkali preparation, achieving zero wastewater discharge in the entire process.

[0047] This invention enables the extraction of crude phenol from phenolic oil with zero wastewater discharge, completely solving the environmental problems associated with the acid-base extraction of phenol from coal tar.

[0048] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or direct application to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A device for extracting crude phenol from phenol-containing distillate oil and treating wastewater with zero discharge, characterized in that, It includes an alkali washing tower (1), a stripping tower (2), a decomposition tower (3), an extraction tower (4), a regeneration tower (5), an adsorption tower (6), a complexing tank (7), an alkali preparation tank (8), and a crystallizer (9); The alkali mixing tank (8) is connected to a solid alkali supply pipeline (10). The top outlet pipeline of the crystallizer (9) is connected to the alkali mixing tank (8). The dilute alkali outlet of the alkali mixing tank (8) is connected to the upper part of the alkali washing tower (1) and the upper part of the adsorption tower (6) through pipelines. The lower part of the alkali washing tower (1) is connected to a phenol-containing distillate oil pipeline (11). The bottom of the alkali washing tower (1) is connected to the upper part of the stripping tower (2) through a pipeline. The bottom of the stripping tower (2) is connected to the decomposition tower (3) through a pipeline. The decomposition tower (3) is connected to an acidic substance supply pipeline (12). The sodium salt solution outlet of the decomposition tower (3) is connected to a pipeline. The extraction tower (4) is connected to the upper part of the extraction tower (4), the extraction tower (4) is connected to the lower part of the extraction tower (4) via an extractant supply line (13), the top outlet line of the extraction tower (4) is connected to the upper part of the regeneration tower (5), the bottom outlet line of the extraction tower (4) is connected to the top of the adsorption tower (6), the top outlet line of the regeneration tower (5) is connected to the extractant supply line (13), the bottom outlet line of the adsorption tower (6) is connected to the upper part of the complexing tank (7), the regeneration outlet of the adsorption tower (6) is connected to the decomposition tower (3), the complexing tank (7) is connected to a complexing agent line (14), and the complexing tank (7) is connected to the crystallizer (9).

2. The apparatus for extracting crude phenol from phenol-containing distillate oil and treating wastewater with zero discharge according to claim 1, characterized in that, The alkaline scrubbing tower (1) can be operated as a single unit or in cascade mode, and the number of stages of the alkaline scrubbing tower (1) is 1-6.

3. The apparatus for extracting crude phenol from phenolic distillate oil and treating wastewater with zero discharge according to claim 2, characterized in that, The extraction tower (4) can be operated as a single unit or in cascade mode, and the number of stages of the extraction tower (4) is 1-6.

4. The apparatus for extracting crude phenol from phenol-containing distillate oil and treating wastewater with zero discharge according to claim 3, characterized in that, The adsorption tower (6) is filled with adsorption packing material.

Images