System for recovering 3, 5-dimethylphenol substances from wastewater

Abstract

The utility model discloses a system for recovering 3, 5-dimethylphenol substances from waste water, which comprises a phenol-containing waste water preparation kettle, a liquid outlet of the phenol-containing waste water preparation kettle is communicated with a liquid inlet of a resin column, a liquid outlet of the resin column is communicated with a liquid inlet of a desorption liquid kettle, and a liquid outlet of the desorption liquid kettle is communicated with a liquid outlet of the resin column. A liquid outlet of the desorption liquid kettle is communicated with a liquid inlet of the extraction device or the filtering device. The device disclosed by the utility model has the characteristics of good process continuity, simple equipment and low operation cost, solves the problem that the phenolic wastewater is difficult to treat, recycles the product 3, 5-dimethylphenol substances, and has obvious environmental protection benefits and economic benefits.

Description

Technical Field

[0001] This utility model relates to a system for recovering phenolic substances, and in particular a system for recovering 3,5-dimethylphenolic substances from wastewater. Background Technology

[0002] Phenolic compounds, such as phenol, cresol, 3,5-dimethylphenol (MX), 4-chloro-3,5-dimethylphenol (PCMX), 2-chloro-3,5-dimethylphenol (OCMX), and 2,4-chloro-3,5-dimethylphenol (DCMX), are highly toxic in the environment and can easily cause serious harm to human health and ecosystems. For example, phenolic compounds can enter the human body through the skin, respiratory tract, and digestive tract, and have neurotoxic and carcinogenic properties. Long-term exposure may lead to symptoms such as headaches, nausea, and liver and kidney damage. In water bodies, phenolic compounds have a certain bioaccumulation effect, are toxic to aquatic organisms such as fish and algae, and can easily cause persistent environmental pollution. At the same time, phenolic substances are highly stable in the environment and are difficult to degrade naturally; therefore, the discharge requirements for phenol-containing wastewater are very strict.

[0003] Phenolic wastewater contains phenolic substances such as 3,5-dimethylphenol, 3-methylphenol, 3,5-dimethylphenol (MX), 4-chloro-3,5-dimethylphenol (PCMX), 2-chloro-3,5-dimethylphenol (OCMX), and 2,4-chloro-3,5-dimethylphenol (DCMX). Among them, PCMX and DCMX are commercially available broad-spectrum antibacterial agents that can effectively kill and inhibit microorganisms in activated sludge, making wastewater treatment extremely difficult.

[0004] Currently, the MX, PCMX, and DCMX industries mainly use Fenton reaction or Fenton-like reaction oxidation to treat phenol-containing wastewater. There are no reports of other advanced technologies being applied. The Fenton reaction uses hydrogen peroxide and ferrous sulfate to generate highly oxidizing hydroxyl radicals to degrade phenolic substances. It has the advantages of simple operation, broad spectrum, and the reaction products are mainly water and carbon dioxide, with no secondary pollution. However, it also has disadvantages such as requiring highly acidic reaction conditions and a large amount of acid and alkali to adjust the pH; and producing a large amount of iron-containing sludge. In addition, the high price of hydrogen peroxide leads to high costs for treating phenol-containing wastewater. On the other hand, the phenolic substances in the wastewater are originally raw materials, products, and by-products with certain economic value, and are directly decomposed and consumed.

[0005] Macroporous adsorption resins are a class of polymeric adsorption materials developed since the 1960s that do not contain exchange groups, possess a macroporous structure, and have a large specific surface area. They can selectively separate, enrich, and purify organic matter from aqueous solutions through physical adsorption. The preparation of macroporous resins typically uses styrene as a monomer, divinylbenzene as a crosslinking agent, and toluene or xylene as a porogen. Crosslinking polymerization forms spherical particles with a porous framework structure, generally with a particle size of 20–60 μm. Macroporous adsorption resins are physically and chemically stable, insoluble in acids, alkalis, and organic solvents, and unaffected by inorganic salts, strong ions, and low-molecular-weight compounds. However, it also has the disadvantage of high solvent consumption, which limits its use. For example, the Chinese patent application with publication number CN108715493A uses macroporous resin to adsorb o-aminophenol, but after each round of adsorption, a large amount of regenerated liquid is required to desorb the adsorbed o-aminophenol. The desorbed regenerated liquid needs to be distilled and purified to recover the solvent and o-aminophenol, which increases the investment in supporting facilities and the cost of solvent use, and also brings flammable and explosive safety hazards. At the same time, the alcohol solvent in the regenerated liquid inevitably enters the aqueous phase, increasing the COD of the wastewater and complicating the wastewater treatment problem, making it unsuitable for industrial production.

[0006] Therefore, by combining the physical and chemical properties of macroporous adsorption resins and phenol-containing wastewater, a wastewater treatment method with good process continuity, simple equipment, and low operating costs can be developed. At the same time, phenolic substances in the wastewater can be recovered, which will not only solve the sewage treatment problem, but also recover the product, generating significant environmental benefits and certain economic benefits. Utility Model Content

[0007] The technical problem to be solved by this utility model is to provide a system for recovering 3,5-dimethylphenol from wastewater, which reduces costs, ensures safe production, simplifies wastewater treatment, and is suitable for industrial production, in order to address the shortcomings of existing technologies.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0009] A system for recovering 3,5-dimethylphenol from wastewater includes a phenol-containing wastewater mixing tank, the outlet of which is connected to the inlet of a resin column, the outlet of which is connected to the inlet of a desorption tank, and the outlet of which is connected to the inlet of an extraction device or a filtration device.

[0010] This invention first introduces a strong alkali into a resin column. After the resin column is decomposed, the resulting eluent can be extracted by an extraction device or filtered by a filtration device to recover phenolic substances. This reduces costs, ensures safe production, and simplifies wastewater treatment.

[0011] In a preferred embodiment of the present invention, the organic phase outlet of the extraction device is connected to the inlet of the concentration vessel, and the aqueous phase outlet of the extraction device is connected to the inlet of the phenol-containing wastewater preparation vessel.

[0012] In a preferred embodiment of this invention, the outlet of the filtration device is connected to the inlet of the second concentration vessel.

[0013] In a preferred embodiment of this utility model, the outlet of the resin column is connected to the inlet of the biological treatment tank, and the outlet of the biological treatment tank is connected to the inlet of the wastewater recycling device.

[0014] Wastewater is directly discharged into the biological treatment tank after passing through the resin column and then fed into the wastewater recycling device.

[0015] In a preferred embodiment of this utility model, the inlet of the phenol-containing wastewater mixing vessel is connected to the outlet of the first acid storage tank.

[0016] In a preferred embodiment of this utility model, the outlet of the phenol-containing wastewater mixing tank is connected to the inlet of the second filtration device, and the outlet of the second filtration device is connected to the inlet of the resin column.

[0017] The second filtration device is preferably a bag filter. Acidified phenol-containing wastewater can be filtered through a bag filter to remove phenolic substances and foreign matter precipitated after acidification.

[0018] In a preferred embodiment of the present invention, the system for recovering 3,5-dimethylphenol from wastewater further includes an alkaline water tank, the outlet of which is connected to the inlet of the resin column.

[0019] In a preferred embodiment of the present invention, the system for recovering 3,5-dimethylphenol from wastewater further includes a second acid storage tank, the outlet of which is connected to the inlet of the resin column.

[0020] In a preferred embodiment of this utility model, 2-4 phenol-containing wastewater mixing tanks and 2-4 resin columns are provided.

[0021] The system is equipped with multiple sets of phenol-containing wastewater preparation tanks and resin columns. While some resin columns are adsorbing, other resin columns can be desorbed and regenerated first, thereby improving production efficiency.

[0022] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0023] The analytical process of this invention only requires passing a certain volume of production wastewater through an alkaline water tank and adding a strong alkali to the wastewater to wash the resin in the resin column. This converts the adsorbed phenolic substances in the resin into sodium phenolate, thus completing the analytical and regeneration process of the macroporous resin. The entire process avoids the use of organic solvents and combines the analytical and regeneration processes into one. After analytical treatment, a certain amount of production wastewater from a second acid storage tank is added to neutralize the resin column, allowing for re-adsorption, further simplifying the operation. After acidification, the analytical solution is extracted and concentrated in an extraction device or filtered using a filtration device to recover the phenolic substances. The value of the phenolic substances recovered per ton of water is approximately 120 yuan, achieving a double harvest of environmental and economic value. This invention features good process continuity, simple equipment, stable operation, and low cost, solving the problem of difficult treatment of phenol-containing wastewater and recovering 3,5-dimethylphenol, demonstrating significant environmental and economic benefits. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model.

[0025] Figure 2 This is a structural schematic diagram of Embodiment 2 of the present invention.

[0026] Figure 3 This is a flowchart of an embodiment of the present invention.

[0027] Among them, 1 is a phenol-containing wastewater mixing tank, 2 is a resin column, 3 is a desorption tank, 4 is an extraction device, 5 is a filtration device, 6 is a concentration tank, 7 is a second concentration tank, 8 is a biochemical pool, 9 is a wastewater recovery device, 10 is a first acid storage tank, 11 is an alkaline water tank, and 12 is a second acid storage tank. Detailed Implementation

[0028] Example 1

[0029] like Figure 1 , Figure 3As shown, a system for recovering 3,5-dimethylphenol from wastewater includes a phenol-containing wastewater preparation vessel 1. The outlet of the phenol-containing wastewater preparation vessel 1 is connected to the inlet of a resin column 2. The outlet of the resin column 2 is connected to the inlet of a desorption vessel 3. The outlet of the desorption vessel 3 is connected to the inlet of an extraction device 4. The organic phase outlet of the extraction device 4 is connected to the inlet of a concentration vessel 6, and the aqueous phase outlet of the extraction device 4 is connected to the inlet of the phenol-containing wastewater preparation vessel 1. The outlet of the resin column 2 is connected to the inlet of a biological treatment tank 8, and the outlet of the biological treatment tank 8 is connected to the inlet of a wastewater recovery device 9. The inlet of the phenol-containing wastewater preparation vessel 1 is connected to the outlet of a first acid storage tank 10. The outlet of the phenol-containing wastewater preparation vessel 1 is connected to the inlet of a second filtration device, and the outlet of the second filtration device is connected to the inlet of the resin column 2. The outlet of the alkaline water tank 11 is connected to the inlet of the resin column 2. The outlet of the second acid storage tank 12 is connected to the inlet of the resin column 2. Two phenol-containing wastewater mixing tanks 1 and two resin columns 2 are provided.

[0030] The system for recovering 3,5-dimethylphenolic compounds from wastewater includes the following operational steps:

[0031] 1: Resin column 2 is 800mm in diameter and 2400mm in height. It contains about 1.2 cubic meters of macroporous resin. The resin should be cleaned before use (conventional resins generally contain unpolymerized monomers, pore-forming agents and other organic matter, which need to be cleaned with organic solvents).

[0032] 2: Add a strong alkaline alcohol solution to alkaline water tank 11, stir evenly, and then pump it into the macroporous resin column to activate the macroporous resin. Two resin columns 2 are connected in series. The used ethanol is sent to the distillation column for distillation and recovery.

[0033] 3: Pump 3 tons of wastewater from the high-concentration equalization tank into the phenol-containing wastewater mixing tank 1. Then, 30 kg of concentrated sulfuric acid is introduced from the first acid storage tank 10 and then into the phenol-containing wastewater mixing tank 1. After stirring evenly, the mixture is pumped into the resin column 2 for neutralization. The two resin columns 2 are connected in series, and the waste liquid containing ethanol is sent to the distillation tower for recovery.

[0034] 4. Pump 5 tons of wastewater from the high-concentration equalization tank into the second acid storage tank, add concentrated sulfuric acid to adjust the pH to acidic, stir evenly, and then pump it into resin column 2 for adsorption. The two resin columns 2 are connected in series. After adsorbing ~84 tons of wastewater, stop pumping the wastewater to be adsorbed into the first resin column 2, and use the second resin column 2 alone to continue adsorbing wastewater (note that the adsorption volume of a single resin column should not exceed 60 tons). The remaining liquid is sent to the sewage treatment plant for treatment and then discharged. The first resin column 2 enters the analysis step.

[0035] 5: Pump 4 tons of wastewater into the alkaline water tank 11 from the high-concentration equalization tank, add alkaline solution, stir evenly, and then pump it into the resin column 2 to desorb the phenolic substances adsorbed by the macroporous resin column. The desorbed liquid is collected into the desorption vessel 3.

[0036] 6: Add concentrated sulfuric acid to the eluent in the desorption vessel 3 to adjust the pH to acidic and pump it to the extraction device 4. Add the extraction solvent tetrachloroethylene, stir evenly, and let it stand to separate into layers. The lower tetrachloroethylene phase is sent to the workshop to recover phenolic substances and tetrachloroethylene, yielding 506 kg of phenolic substances. The aqueous phase is pumped back to the mixing tank for adsorption by the macroporous resin.

[0037] 7: Pump 3 tons of wastewater from the high-concentration equalization tank into the phenol-containing wastewater mixing tank 1, add concentrated sulfuric acid, stir evenly, and then pump it into resin column 1 for neutralization. After neutralization, pump the wastewater back to the mixing tank to adjust the pH to acidic. Then connect the first resin column 2 in series with the second resin column 2 for series adsorption.

[0038] 8: When the volume of the second resin column 2 adsorbing alone and co-adsorbing as the first stage of series adsorption reaches 84 tons, the second resin column 2 begins to desorb according to step 5.

[0039] The first resin column 2 and the second resin column 2 can be used alone or alternately for adsorption and desorption to ensure the continuity of the wastewater treatment process.

[0040] Example 2

[0041] like Figure 2 , Figure 3 As shown, a system for recovering 3,5-dimethylphenol from wastewater includes a phenol-containing wastewater mixing tank 1. The outlet of the mixing tank 1 is connected to the inlet of a resin column 2. The outlet of the resin column 2 is connected to the inlet of a desorption tank 3. The outlet of the desorption tank 3 is connected to the inlet of a filter device 5. The outlet of the filter device 5 is connected to the inlet of a second concentration tank 7. The outlet of the resin column 2 is connected to the inlet of a biological treatment tank 8. The outlet of the biological treatment tank 8 is connected to the inlet of a wastewater recovery device 9. The inlet of the phenol-containing wastewater mixing tank 1 is connected to the outlet of a first acid storage tank 10. The outlet of the phenol-containing wastewater mixing tank 1 is connected to the inlet of a second filter device, and the outlet of the second filter device is connected to the inlet of the resin column 2. The outlet of an alkaline water tank 11 is connected to the inlet of the resin column 2. The outlet of the second acid storage tank 12 is connected to the inlet of the resin column 2. Two phenol-containing wastewater mixing tanks 1 and two resin columns 2 are provided.

Claims

1. A system for recovering 3,5-dimethylphenol from wastewater, comprising a phenol-containing wastewater mixing tank (1), wherein the outlet of the phenol-containing wastewater mixing tank (1) is connected to the inlet of a resin column (2), characterized in that, The outlet of the resin column (2) is connected to the inlet of the desorption vessel (3), and the outlet of the desorption vessel (3) is connected to the inlet of the extraction device (4) or the filtration device (5).

2. The system for recovering 3,5-dimethylphenol from wastewater according to claim 1, characterized in that, The organic phase outlet of the extraction device (4) is connected to the inlet of the concentration vessel (6), and the aqueous phase outlet of the extraction device (4) is connected to the inlet of the phenol-containing wastewater mixing vessel (1).

3. The system for recovering 3,5-dimethylphenol from wastewater according to claim 1, characterized in that, The outlet of the filter device (5) is connected to the inlet of the second concentration vessel (7).

4. The system for recovering 3,5-dimethylphenol from wastewater according to claim 1, characterized in that, The outlet of the resin column (2) is connected to the inlet of the biochemical tank (8), and the outlet of the biochemical tank (8) is connected to the inlet of the sewage recycling device (9).

5. The system for recovering 3,5-dimethylphenol from wastewater according to any one of claims 1-4, characterized in that, The inlet of the phenol-containing wastewater mixing vessel (1) is connected to the outlet of the first acid storage tank (10).

6. The system for recovering 3,5-dimethylphenol from wastewater according to any one of claims 1-4, characterized in that, The outlet of the phenol-containing wastewater mixing tank (1) is connected to the inlet of the second filter device, and the outlet of the second filter device is connected to the inlet of the resin column (2).

7. The system for recovering 3,5-dimethylphenol from wastewater according to any one of claims 1-4, characterized in that, It also includes an alkaline water tank (11), the outlet of which is connected to the inlet of the resin column (2).

8. The system for recovering 3,5-dimethylphenol from wastewater according to any one of claims 1-4, characterized in that, It also includes a second acid storage tank (12), the outlet of which is connected to the inlet of the resin column (2).

9. The system for recovering 3,5-dimethylphenol from wastewater according to any one of claims 1-4, characterized in that, The phenol-containing wastewater mixing tank (1) is provided with 2-4 units, and the resin column (2) is provided with 2-4 units.

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