Process for treating coal tar deep processing phenol-containing wastewater through solid-phase liquid membrane method

Abstract

The invention belongs to the field of industrial wastewater treatment, and particularly relates to a process for treating coal tar deep processing phenol-containing wastewater by a solid-phase liquid membrane method. According to the technology for treating the phenol-containing wastewater deeply processed by the coal tar through the solid-phase liquid membrane method, solid-phase adsorption and an emulsion liquid membrane are combined, the solid-phase adsorption serves as supplement, the emulsion liquid membrane and a porous solid adsorption material are combined to treat the phenol-containing wastewater, and the problem that the treatment effect of a single treatment method is not satisfactory can be effectively solved; meanwhile, emergency situations such as change of phenol content in the wastewater and liquid membrane rupture can be effectively handled, the treatment effect of volatile phenol in the wastewater is ensured, and the coping capacity for incoming water quality change or liquid membrane swelling rupture and the like is improved; the process is combined into a form of a process package, is simple and convenient to operate and manage, can complete absorption and release of phenolic substances in the wastewater in one step, is simple in treatment equipment and process, is high in liquid membrane permeation speed and selectivity, is low in energy consumption, greatly saves the consumption of an extraction solvent, and reduces the treatment cost of the phenolic wastewater.

Description

Technical Field

[0001] The invention belongs to the field of industrial wastewater treatment, and specifically relates to a process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method. Background Art

[0002] Phenolic wastewater mainly comes from coal tar deep processing and industrial production processes such as coking, petrochemicals, and gas power plants. The main pollutants in phenolic wastewater are phenolic compounds, such as phenol, cresol, xylenol, and nitrocresol, etc. The phenol concentration is as high as 2000-20000 mg / L. It has the characteristics of high phenol concentration, large variability, complex water quality, and high hazard. It is one of the types of wastewater that is more difficult to treat in the field of industrial wastewater treatment.

[0003] Phenol and other phenolic compounds in phenolic wastewater have high structural stability and are difficult to degrade by general treatment methods. In addition, the phenol content in such wastewater is high. If it is not recovered, it will cause environmental pollution and waste of resources. At present, extraction + back extraction or extraction + distillation is the most common method for treating phenolic wastewater in the industry. The extraction + back extraction or extraction + distillation process chain is complex, the consumption of chemical agents is large, the equipment investment is large, and the operating cost is high, which limits the promotion and application of this technology.

[0004] The solid phase liquid membrane method is a new wastewater treatment separation technology that combines physical adsorption with membrane separation technology. During the separation process, the phenol to be separated can be extracted and stripped at the same time, and the separation and concentration can be achieved through liquid membrane transmission. The process has the advantages of simplicity and high efficiency, high selectivity, high separation efficiency, and the emulsion can be reused after demulsification. Summary of the invention

[0005] The invention provides a solid phase liquid membrane method for treating phenol-containing wastewater from coal tar deep processing, which is used to solve the problems of complex extraction process, small extraction agent distribution coefficient and low extraction efficiency in the existing extraction process.

[0006] The present invention is achieved through the following technical solutions:

[0007] A process for treating phenol-containing wastewater from coal tar deep processing by solid phase liquid membrane method mainly comprises the following steps:

[0008] S1: Phenol-containing wastewater is temporarily stored in a temporary storage tank, and the suspended solids with relatively large particle sizes in the wastewater are removed by a clarification and separation device. The treated wastewater enters the reaction tower;

[0009] S2: adding solvent, sodium hydroxide solution, surfactant, stabilizer and carrier into the reaction tower;

[0010] S3: A flat-plate cyclone agitator is installed in the reaction tower, and the solvent, sodium hydroxide solution, surfactant, stabilizer and carrier are formed into a liquid film by the flat-plate cyclone agitator, and the film is impregnated on the porous solid material with a high specific surface area to form a liquid film layer;

[0011] S4: The porous solid material loaded with the liquid membrane layer is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid membrane and the pore enrichment of the porous solid material;

[0012] S5: When the porous solid material loaded with the liquid film layer is saturated with the adsorption of the phenolic substance, it is repeatedly washed with clean water in the water storage tank to make the saturated liquid film fall off from the surface of the porous solid material;

[0013] S6: The absorbed saturated liquid film enters the subsequent demulsifier for demulsification, and the sodium phenol salt in the inner phase wrapped by the emulsion liquid film is released. The emulsion returns to the front reaction tower to form a film again for the next round of absorption of phenolic substances. The treated wastewater is discharged through the drain pipe;

[0014] S7: The porous solid material after adsorption saturation enters the regeneration tank and is regenerated by solvent. The regenerated porous solid material can be recycled again.

[0015] The solvent described in step S2 is one of kerosene, isopropyl ether, methyl isobutyl ketone, dimethylformamide, and dimethyl sulfoxide; the concentration of the sodium hydroxide solution is 10%-20%; the surfactant is a mixture of anionic polymer surfactant LMS-3 and non-ionic polymer surfactant LMA-1 in a molar ratio of 1.5-3:1; the stabilizer is one of polyethylene oxide, polyoxypropylene polyol, epoxidized ethylene polyol, polycaprolactone and polyethylene terephthalate; the carrier is one of polyethylene glycol complex, polypropylene alcohol complex, polyaminoethanol complex and polyethylene glycol polypropylene alcohol copolymer; the mass ratio of the solvent, surfactant, stabilizer and carrier is 75%-90%: 4%-10%: 0.1%-3%: 2%-15%.

[0016] The flat plate cyclone described in step S3 comprises a flat plate and a central shaft, wherein the rotation speed of the central shaft is 1000-3000 r / min; and the mass ratio of the liquid film to the porous solid material is 2-10:1.

[0017] A solid phase liquid membrane is mainly prepared by forming a liquid membrane with a droplet diameter small enough to be emulsified through a water-in-oil-in-water (W / O / W) system through a flat cyclone and a porous solid adsorption material, wherein the solid adsorption material is one of activated carbon fiber, macroporous resin, zeolite, molecular sieve or activated alumina, which can play a role in solidifying the liquid membrane and make the liquid membrane evenly dispersed on the surface of the porous material. At the same time, the porous material can use its own huge specific surface area and structural characteristics such as micropores and mesopores as a supplementary process to further adsorb phenolic substances in wastewater, ensure the treatment effect of phenol-containing wastewater and make up for the deficiency of a single liquid membrane in the process of absorbing phenolic substances in wastewater; the composite effect of the two is used to further reduce the surface tension of the liquid membrane, making the liquid membrane more stable.

[0018] The flat-plate cyclone agitator can form a spiral annular flow of liquid. The liquid film formed under the stirring of the flat-plate cyclone has a small distribution range of thickness, small volatility of the liquid film, and good stability of the spiral annular flow liquid film. The surfactant is a mixture of anionic polymer surfactant LMS-3 and non-ionic polymer surfactant LMA-1. The composite effect of the two is used to further reduce the surface tension of the liquid film, making the liquid film more stable. The stabilizer can reduce the swelling of the liquid film. The carrier has a hydrophobic group and a hydrophilic group, and can shuttle back and forth between the two interfaces of the liquid film to transfer phenolic substances in the wastewater. Through the selective reaction between the carrier and the phenolic substance, the effective solubility of the phenolic substance in the liquid film is greatly improved.

[0019] Beneficial effects of the present invention:

[0020] The present invention combines solid-phase adsorption and emulsion liquid membrane, with solid-phase adsorption as a supplement, and combines emulsion liquid membrane and porous solid adsorption material to treat phenol-containing wastewater, which can effectively avoid the problem of unsatisfactory treatment effect of a single treatment method, and at the same time can effectively respond to changes in phenol content in wastewater and sudden situations such as liquid membrane rupture, ensure the treatment effect of volatile phenol in wastewater, and improve the ability to respond to changes in incoming water quality or liquid membrane swelling and rupture.

[0021] The process of the present invention is combined into a process package, which is easy to operate and manage, and can complete the absorption and release of phenolic substances in wastewater in one step. The treatment equipment and process are simple, and the liquid membrane penetration speed and selectivity are high, the energy consumption is low, the consumption of extraction solvent is greatly saved, and the treatment cost of phenol-containing wastewater is reduced.

[0022] The sodium phenol salt liberated by the invention can be sold after being recovered, thereby reducing resource waste, improving the economic benefit of sewage treatment, and realizing the harmlessness and resource utilization of phenol-containing wastewater in coal chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic diagram of a process flow of treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method. Figure numbers, 1: temporary storage tank; 2: phenol-containing wastewater inlet pipe; 3: clarification and separation device inlet pipe; 4: clarification and separation device; 5: clarification and separation device outlet pipe; 6: reaction tower; 7: porous solid material combined with liquid film; 8: flat-plate cyclone agitator; 9: NaOH adding pipe; 10: solvent adding pipe; 11: surfactant, stabilizer feeding pipe; 12: carrier feeding pipe; 13: emulsion liquid film collecting pipe; 14: demulsifier; 15: emulsion circulation pipe; 16: drain pipe; 17: water storage tank; 18: lifting pump; 19: regeneration tank. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments and diagrams.

[0025] The experimental methods in the following examples, unless otherwise specified, are conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials and reagents used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0027] Example 1

[0028] See also Figure 1 , this embodiment specifically includes the following steps:

[0029] 1: Wastewater containing 22000 mg / L of phenol enters the phenolic wastewater temporary storage tank 1 through the phenolic wastewater inlet pipe 2 for temporary storage, and then enters the clarification separation device through the clarification separation device inlet pipe 3 to remove suspended particles with larger particle sizes in the wastewater, thus laying a good foundation for subsequent wastewater treatment. The clarified water enters the reaction tower 6 through the clarification separation device outlet pipe 5;

[0030] 2: Add 25L of 40wt% sodium hydroxide solution into the reaction tower 6 through the sodium hydroxide solution adding pipe 9, add 40L of dimethyl sulfoxide through the solvent adding pipe 10, add 1.5kg of LMS-3, 1kg of LMA-1, and 1kg of polyethylene oxide through the surfactant and stabilizer adding pipe 11, and add 5kg of polyethylene glycol complex through the carrier adding pipe 12;

[0031] 3: A flat cyclone stirrer 8 is installed in the reaction tower 6, and dimethyl sulfoxide, 15wt% sodium hydroxide solution, LMS-3, LMA-1, polyethylene oxide and polyethylene glycol complex are stirred by the flat cyclone stirrer 8 at 3000r / min, 35°C, and 30min to form a liquid film. The activated carbon fiber loaded with the liquid film in the reaction tower 6 is impregnated with the liquid film formed by stirring by the flat cyclone stirrer 8 on the activated carbon fiber with a high specific surface area to form a liquid film layer;

[0032] 4: The activated carbon fiber loaded with the liquid film layer in the reaction tower 6 is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid film and the pore enrichment of the activated carbon fiber;

[0033] 5: When the activated carbon fiber loaded with the liquid film layer is saturated with the adsorption of phenolic substances, it is repeatedly washed with clean water in the water storage tank 17 to make the saturated liquid film fall off from the surface of the porous solid material;

[0034] 6: The emulsion film enriched with a large amount of sodium phenolate is discharged into the demulsifier 14 through the emulsion film collecting pipe 13 for demulsification, and the sodium phenolate in the inner phase wrapped by the emulsion film is released for recovery. The emulsion returns to the front reaction tower 6 through the circulation pipe 15 for repeated use to form a film again, and the next round of absorption of phenolic substances is carried out. The treated wastewater is discharged through the drain pipe 16;

[0035] 7: The activated carbon fibers that have been saturated with adsorption enter the regeneration tank 19 to be regenerated using the solvent. The regenerated activated carbon fibers can be recycled and returned to the reaction tower 6 for the next round of adsorption.

[0036] Table 1, reagent parameters used in Example 1

[0037] Drug Name source model parameter Dimethyl sulfoxide Shandong Hairui New Materials Co., Ltd. 0219 250kg Sodium hydroxide Aladdin S431787 5kg LMS-3 Jinan Chuanxi Chemical Co., Ltd. Dus-2 1kg LMA-1 Guangzhou Huazhiwang Chemical Co., Ltd. Ins-7 1kg Polyethylene oxide Henan Chuanda Chemical Co., Ltd. 12-9-6 1kg Polyethylene glycol complex Jiangsu Haian Petrochemical Plant PEG-6000 25kg Activated carbon fiber Shanghai Lijing Activated Carbon Co., Ltd. ZZ-001 25kg

[0038] Table 2, phenol-containing wastewater treatment results in Example 1

[0039] Phenol content Turbidity (NTU) Conductivity (μS / cm) Before treatment 22000mg / L 41 1170 After treatment 200mg / L 3 97 Removal rate 99.1％ 92.7％ 91.7％

[0040] From the analysis of Table 2, it can be seen that the wastewater with a phenol content of 22000 mg / L in this embodiment uses a phenol-containing wastewater treatment process. After being treated by the clarification separation device 4, it enters the reaction tower 6. In the reaction tower 6, the phenolic substances in the wastewater are absorbed by the porous solid material 7 combined with the liquid membrane. The phenol content in the water discharged through the drain pipe 16 is reduced to 200 mg / L, and the removal rate reaches 99.1%.

[0041] The present invention combines solid phase adsorption with emulsion liquid membrane, with solid phase adsorption as a supplement, and combines emulsion liquid membrane with porous solid adsorption material to treat phenol-containing wastewater, which can effectively avoid the problem of unsatisfactory treatment effect of a single treatment method, and can effectively respond to sudden situations such as changes in phenol content in wastewater and liquid membrane rupture, thereby ensuring the treatment effect of volatile phenol in wastewater and improving the ability to respond to changes in incoming water quality or swelling and rupture of liquid membranes.

[0042] Example 2

[0043] See also Figure 1 , this embodiment specifically includes the following steps:

[0044] 1: Phenolic wastewater enters the phenolic wastewater temporary storage tank 1 through the phenolic wastewater inlet pipe 2 for temporary storage, and then enters the clarification separation device through the clarification separation device inlet pipe 3 to remove suspended particles with larger particle sizes in the wastewater, thus laying a good foundation for subsequent wastewater treatment. The clarified water enters the reaction tower 6 through the clarification separation device outlet pipe 5;

[0045] 2: Add 25L of 40wt% sodium hydroxide solution into the reaction tower 6 through the sodium hydroxide solution adding pipe 9, add 40L of polypropylene ether through the solvent adding pipe 10, add 1.5kg of LMS-3, 1kg of LMA-1, and 1kg of polyoxypropylene polyol through the surfactant and stabilizer adding pipe 11, and add 5kg of polyaminoethanol complex through the carrier adding pipe 12;

[0046] 3: A flat cyclone stirrer 8 is installed in the reaction tower 6, and polypropylene ether, 40wt% sodium hydroxide solution, LMS-3, LMA-1, polyoxypropylene polyol and polyaminoethanol complex are stirred by the flat cyclone stirrer 8 at 3000r / min, 35°C, and 30min to form a liquid film. The reaction tower 6 contains activated alumina loaded with the liquid film, and the liquid film formed by stirring by the flat cyclone stirrer 8 is impregnated on the activated alumina with a high specific surface area to form a liquid film layer;

[0047] 4: The activated alumina loaded with a liquid film layer in the reaction tower 6 is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid film and the pore enrichment of the activated alumina;

[0048] 5: When the activated alumina loaded with the liquid film layer is saturated with the adsorption of phenolic substances, it is repeatedly washed with clean water in the water storage tank 17 to make the saturated liquid film fall off from the surface of the porous solid material;

[0049] 6: The emulsion film enriched with a large amount of sodium phenolate is discharged into the demulsifier 14 through the emulsion film collecting pipe 13 for demulsification, and the sodium phenolate in the inner phase wrapped by the emulsion film is released for recovery. The emulsion returns to the front reaction tower 6 through the circulation pipe 15 for repeated use to form a film again, and the next round of absorption of phenolic substances is carried out. The treated wastewater is discharged through the drain pipe 16;

[0050] 7: The activated alumina after adsorption saturation enters the regeneration tank 19 to be regenerated by solvent, and the regenerated activated carbon fiber can be recycled and returned to the reaction tower 6 for the next round of adsorption.

[0051] Table 3, reagent parameters used in Example 2

[0052] Drug Name source model parameter Isopropyl ether Jiangsu Xinjuku New Materials Co., Ltd. 926-65-8 1kg Sodium hydroxide Aladdin S431787 5kg LMS-3 Jinan Chuanxi Chemical Co., Ltd. Dus-2 1kg LMA-1 Guangzhou Huazhiwang Chemical Co., Ltd. Ins-7 1kg Polyoxypropylene polyol Jining Hongming Chemical Reagent Co., Ltd. 330 1kg Polyaminoethanol complex Jufuyuan Plastic Technology Co., Ltd. 2300-7301 1kg Activated Alumina Guangdong Xintao Technology Co., Ltd. 1302-74-5 25kg

[0053] Table 4, phenol-containing wastewater treatment results in Example 2

[0054] Phenol content Turbidity (NTU) Conductivity (μS / cm) Before treatment 22000mg / L 39 1250 After treatment 180mg / L 4 103 Removal rate 99.18％ 89.74％ 91.76％

[0055] From the analysis of Table 4, it can be seen that the wastewater with a phenol content of 22000 mg / L in this embodiment uses a phenol-containing wastewater treatment process. After being treated by the clarification separation device 4, it enters the reaction tower 6. In the reaction tower 6, the phenolic substances in the wastewater are absorbed by the porous solid material 7 combined with the liquid membrane, and the phenol content in the water discharged through the drain pipe 16 is reduced to 200 mg / L, and the removal rate reaches 99.18%.

[0056] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method, characterized in that: The following steps are involved: S1: Phenol-containing wastewater is temporarily stored in a temporary storage tank, and the suspended solids with relatively large particle sizes in the wastewater are removed by a clarification and separation device. The treated wastewater enters the reaction tower; S2: adding solvent, sodium hydroxide solution, surfactant, stabilizer and carrier into the reaction tower; S3: A flat-plate cyclone agitator is installed in the reaction tower, and the solvent, sodium hydroxide solution, surfactant, stabilizer and carrier are formed into a liquid film by the flat-plate cyclone agitator, and the film is impregnated on the porous solid material with a high specific surface area to form a liquid film layer; S4: The porous solid material loaded with the liquid membrane layer is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid membrane and the pore enrichment of the porous solid material; S5: When the porous solid material loaded with the liquid film layer is saturated with the adsorption of the phenolic substance, it is repeatedly washed with clean water in the water storage tank to make the saturated liquid film fall off from the surface of the porous solid material; S6: The absorbed saturated liquid film enters the subsequent demulsifier for demulsification, and the sodium phenol salt in the inner phase wrapped by the emulsion liquid film is released. The emulsion returns to the front reaction tower to form a film again, and the next round of absorption treatment of phenolic substances is carried out. The completed wastewater is discharged through the drain pipe; S7: The porous solid material after adsorption saturation enters the regeneration tank and is regenerated by solvent. The regenerated porous solid material can be recycled again.

2. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The solvent described in step S2 is one of kerosene, isopropyl ether, methyl isobutyl ketone, dimethylformamide, and dimethyl sulfoxide.

3. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The concentration of the sodium hydroxide solution described in step S2 is 10%-20%.

4. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The surfactant described in step S2 is a mixture obtained by mixing anionic polymer surfactant LMS-3 and nonionic polymer surfactant LMA-1 in a molar ratio of 1.5-3:

1.

5. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The stabilizer described in step S2 is one of polyethylene oxide, polyoxypropylene polyol, epoxidized ethylene polyol, polycaprolactone and polyethylene terephthalate.

6. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The carrier described in step S2 is one of polyethylene glycol complex, polypropylene alcohol complex, polyaminoethanol complex and polyethylene glycol polypropylene alcohol copolymer.

7. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The mass ratio of the solvent, surfactant, stabilizer and carrier described in step S2 is 75%-90%: 4%-10%: 0.1%-3%: 2%-15%.

8. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The flat plate cyclone described in step S3 comprises a flat plate and a central shaft, wherein the rotation speed of the central shaft is 1000-3000 r / min.

9. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The porous solid material described in step S3 is one of activated carbon fiber, macroporous resin, zeolite, molecular sieve and activated alumina.

10. The process for treating phenol-containing wastewater from coal tar deep processing by a solid phase liquid membrane method according to claim 1, characterized in that: The mass ratio of the liquid film to the porous solid material in step S3 is 2-10:1.

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