TWI788980B - A method and system for treating and recycling cotton dyeing waste dye liquor - Google Patents

Abstract

The invention discloses a method for treating and recycling cotton dyeing waste dyeing liquid, which uses electrocoagulation to capture and oxidatively decomposes to completely decolorize the waste dyeing liquid to obtain recovered brine, and further uses a concentrating device to distill and concentrate the recovered brine to obtain brine that meets the technological requirements Concentration and distilled water are used in the dyeing process. According to the treatment requirements of waste dyeing liquid, electrocoagulation, air flotation flocculation, neutralization coagulation, static sedimentation, filtration to remove slag, oxidation decolorization, filtration separation, concentrated distillation procedures are carried out to obtain brine that meets the requirements of the dyeing process. Concentration and distilled water are used in the dyeing process, so that the salt content in the waste water is not destroyed, and can be used in the dyeing process, so that the salt and water in the waste dyeing liquid treatment are not discharged, but can be recycled.

Description

A method and system for treating and recycling cotton dyeing waste dyeing liquor

The invention relates to cotton dyeing waste water treatment and reuse technology, especially for the treatment of high-salt and high-concentration waste dyeing liquid. The waste dyeing liquid is collected by shunting, and the coagulation and sedimentation of the dye in the dyeing liquid is removed, and the residual dye that cannot be removed is oxidatively decomposed. , to achieve complete decolorization technology, to further concentrate the brine concentration that meets the requirements of the dyeing process and to use distilled water in the dyeing process, and to realize the recycling technology of waste dyeing liquid.

Cotton dyeing wastewater contains most of the dyestuffs and dye accelerators such as sodium sulfate Na2SO4 or sodium chloride NaCl, so removing them for independent treatment can solve most of the wastewater treatment problems. The dye part needs to be treated with COD, The control of salt discharge is an important issue of environmental protection in the future, and recycling has to be considered. In order to reuse the waste dyeing liquid, it must be considered that no new substances will be produced after treatment, and the color must be completely removed from damage. Therefore, waste dyeing liquid must be available. The slag discharge mechanism allows the impurities in the waste dyeing liquid to be removed through capture to realize the feasibility of treatment and reuse.

Waste dyeing liquid is mainly dyeing waste liquid and washing water, which contains more than 95% of residual dyes, leveling agents, dyeing accelerators such as sodium sulfate or sodium chloride and color fixing agents such as sodium carbonate, which are alkaline and highly For COD wastewater, the treatment methods that do not change its composition are:

1. Adsorption method: The most widely used physical treatment method is the adsorption method. The method is to mix the powder or particles of activated carbon and clay porous material with wastewater, or let the wastewater pass through a filter bed composed of its particles, so that the pollutants in the wastewater are adsorbed on the surface of the porous material or removed by filtration. The adsorption rate, BOD removal rate and COD removal rate of activated carbon can reach 93%, 92% and 63% respectively.

2. Chemical oxidation method: chemical oxidation method uses a strong oxidant to break the chain of the dye molecular chromogenic group to achieve the purpose of decolorization. This method is widely used in the treatment of stable and refractory dyes, including ozone oxidation, Fenton oxidation and high temperature. deep oxidation.

3. Ozone oxidation method: Usually, the oxidation of organic matter by ozone includes two ways, direct reaction and indirect reaction. The direct reaction is that ozone directly reacts with organic pollutants through cycloaddition, electrophile or nucleophilic action, and the indirect reaction is that ozone reacts with alkali, Under the action of light, etc., free radicals such as hydroxyl (OH) with stronger oxidation ability are generated to destroy cyclic compounds such as benzene, naphthalene, anthracene and other chromophoric groups to achieve decolorization effect, and the secondary biochemical treatment of printing and dyeing wastewater is advanced by ozone oxidation method The removal rates of COD and chroma are 75% and 85% respectively.

4. Fenton oxidation method: Fenton oxidation method uses hydrogen peroxide (H2O2) to generate highly reactive OH radicals under the catalysis of ferrous ions (Fe2+). Its oxidative properties are not selective and can be compared with most The organic matter reacts to degrade it. Fenton reagent is used to treat the printing and dyeing water of the dyeing factory. Considering the influence of reaction time, ferrous sulfate dosage, hydrogen peroxide dosage and pH value on the wastewater chromaticity and COD treatment effect, it is found that the best Under the process conditions, the COD removal rate is greater than 80%, and the chroma removal rate is 95% Above, it generally reacts under acidity, and the treatment cost is high when the cotton dyeing wastewater is alkaline.

From the above, it can be seen that there are still considerable technical difficulties in the treatment of waste dyeing liquor, the removal rate of color is difficult, it is not easy to realize, and it is difficult to change the composition of brine for reuse. The existing treatment technology is explained as follows:

1. Chinese patent application number 201310078136.X is a method for treating wastewater dyed with reactive dyes. It adds 2-8g/L peracetic acid to reactive dye wastewater, raises the temperature of wastewater to 90~95°C, and keeps it warm for 25~30min. The oxidized components released by heating peracetic acid destroy the conjugated structure of reactive dyes to achieve effective decolorization. The peracetic acid is a mixture of sulfuric acid, hydrogen peroxide and glacial acetic acid. Although this decolorization method decomposes and destroys the dye, However, its components still exist in the treated water, and the discharge will not cause environmental pollution. Although decolorization and discharge are achieved, there is no reuse design and no verification of the feasibility of reuse.

2. Chinese patent application number 201510075856.X is a kind of reactive dye waste water reuse dyeing method, it is characterized in that comprising the following steps:

(1) Decolorization: According to the chroma of the dyed wastewater, add 5~30g/L of calcium ions or magnesium ions or a mixture of the two to the wastewater for precipitation and decolorization. After the precipitation is completed, centrifuge for 5 minutes, and take the supernatant ;

(2) Softening: Add 0~10g/L sodium carbonate to the supernatant of step (1), stir mechanically for 3 minutes, until no precipitation occurs in the waste water, remove residual calcium ions or magnesium ions, centrifuge for 5 minutes, and take supernatant;

(3) Neutralization: According to the salt contained in the dyeing waste liquid is sodium chloride or sodium sulfate, to Add corresponding hydrochloric acid or sulfuric acid in the supernatant in step (2), neutralize residual sodium carbonate;

(4) salinity measurement: adopt the salinity of the neutralization treatment water of step (3) of salinometer measurement;

(5) Dyeing: In the recycled water, according to the dyeing requirements, use sodium sulfate, sodium chloride or pure water to adjust the salinity, supplement reactive dyes, and use the dyeing methods commonly used for reactive dyes for dyeing.

The calcium ion is Ca0 or Ca(OH)2 calcium salt, and the magnesium ion is MgCl2 or MgSO4 magnesium salt. From the above, the use of calcium and magnesium ions to adsorb and decolorize basically increases the hardness of the water, which is unfavorable for dyeing. After decolorization, a large amount of sludge is formed, which has the risk of secondary pollution, and the wastewater has no diversion treatment. The amount of wastewater is large, and the wastewater contains dyes. There are impurities such as pre-treatment agents, leveling agents, color-fixing agents, softeners, and dissolved substances. There is no removal mechanism, let alone an oxidative decomposition mechanism. There are risks in use, and they cannot be completely captured and removed. There are risks of different salts, and water-soluble dyes cannot be decolorized through absorption, which will relatively affect the future dyeing process, and a more complete treatment mechanism needs to be developed.

The main purpose of the present invention is to establish a new business opportunity for the recycling of waste dyeing liquor; the salt and water in the waste dyeing liquor can be reused; emissions, thereby avoiding environmental pollution, improving the economic benefits of dyeing factories, and creating new business opportunities for recycling in dyeing factories.

Another main purpose of the present invention is to ensure that the reuse of waste dyeing liquor does not affect the dyeing quality; The components that require recycled water must meet the requirements of dyeing applications. It must not destroy the original required components and must not add new substances. The salt in the liquid is uniformly converted into a dyeing accelerator, and other salts must not be added, and substances such as leveling agents and influential dyeing metal ions need to be removed.

Another main purpose of the present invention is to solve the problem of waste water treatment and discharge; the salt in the waste water will disappear because of no treatment operation, and the excessive salt will affect the ecological environment. At present, there are requirements for controlling the salt content in waste water, and cotton dye Wastewater contains a lot of salt, which will inevitably increase the difficulty of treatment. By diverting the waste dyeing liquor for reuse, more than 90% of the salt in the dyeing factory can be reused, which can meet future environmental protection requirements.

In order to achieve the purpose of the above invention, the reuse of cotton mill wastewater was analyzed and studied, and the process procedures of cotton mills, raw materials used and pollutants formed, and the benefits of possible treatment and reuse were considered, and it was further found that in the overall wastewater, waste dyeing liquid Treatment and reuse is in line with economic benefits and can improve the treatment efficiency of the dyeing factory. More than 90% of the salts and more than 95% of the residual dyes contained in the waste dyeing liquor are collected by shunting, and a small amount of wastewater treatment can solve the problem of wastewater treatment. Therefore, the waste The dyeing liquor is treated independently, and a method for the treatment and reuse of cotton dyeing waste dyeing liquor has been specially developed, as shown in Figure 1:

(1) Utilize shunt to collect waste dye liquor;

The waste dyeing liquid can be collected by shunting to eliminate pre-treatment and post-treatment wastewater, so as to simplify the waste dyeing liquid. The waste dyeing liquid refers to the dyeing liquid for dyeing and its cleaning water. The waste dyeing liquid discharged in the dyeing process accounts for about 20% of the wastewater. %, containing dyeing accelerators such as sodium sulfate or sodium chloride, leveling agents, dyes and color fixing agents such as sodium carbonate, it is a high-chroma, high-salt wastewater. Among them, the darker the dyed color, the more dyeing aids, soda ash, and leveling dosage are put into;

(2) Use the electrocoagulation system to treat the insoluble and dissolved pollutants in the waste dyeing liquid, and retain the dye accelerator and color fixing agent;

The electroflocculation system has the functions of electrolysis, capture, coagulation and sedimentation. It releases iron ions to capture leveling agents, dyes and impurities in the waste dyeing liquid, and further converts them into sludge. It is a very efficient treatment solution;

(3) Utilize acid to neutralize sodium carbonate in the waste dyeing liquor, and convert it into a dyeing accelerator;

Cotton dyeing needs to be colored in an alkaline environment, so a large amount of sodium carbonate needs to be invested, while cotton dyeing requires a large amount of sodium salt as a dyeing accelerator, which can be sodium sulfate or sodium chloride, and sulfuric acid can be used to convert sodium carbonate into sodium sulfate

Na ₂ CO ₃ +H ₂ SO ₄ →Na ₂ SO ₄ +CO ₂ +H2O

Convert sodium carbonate to sodium chloride to use hydrochloric acid

Na ₂ CO ₃ +2HCl→2NaCl+CO ₂ +H2O

Through the neutralization of acid and alkaline, the salt content in the recovered waste dyeing liquid can be made consistent;

Establish hydrogen peroxide deep oxidation technology to decompose and recover the residual dye in the dye solution, and obtain transparent and colorless recovered brine;

Recycled waste dyeing liquid can be neutralized to obtain a dyeing accelerator with consistent components, and the residual dye must be further removed before it can be effectively recovered. The chroma of the recycled dyeing liquid is not high, and it is becoming more and more difficult to remove. This is the current method of various oxidation technologies. The removal of blind spots and chromaticity requires higher cost to achieve complete removal, while hydrogen peroxide can effectively decolorize, for To solve the problem of decolorization, especially establish hydrogen peroxide deep oxidation technology to solve the problem of decolorization of recycled dye liquor; hydrogen peroxide is only used for decolorization, the effect is not good, and it often takes a large amount of 10 hours to more than 1 day to complete, and the residual hydrogen peroxide will also Affect the dyeing function. At present, the use of hydrogen peroxide is basically not considered in the treatment and reuse of dyeing wastewater, and the cost of hydrogen peroxide is high, which is relatively heavy. To improve the decolorization function of hydrogen peroxide, the common method is to carry out at a high temperature above 98 ° C, and high temperature treatment Relatively increased heat energy loss, the amount of input hydrogen peroxide is also large, which affects the recovery efficiency; in order to solve the above difficulties, especially for the development and research of hydrogen peroxide decolorization efficiency, the use of activated carbon to catalyze hydrogen peroxide to generate OH free radicals is used to recover the remaining dyes in the dye solution. Decolorization is destroyed to obtain transparent brine, and activated carbon is further used to absorb decolorization reactants to improve the purity of recovered brine to achieve the purpose of complete decolorization. The hydrogen peroxide detector is used to measure the change of decolorization reaction volume, and the use of color acquisition to track the color change of the reaction process establishes an effective To track the measurement mechanism of the decolorization reaction and realize the optimized operation plan, a special hydrogen peroxide deep oxidation method is set up, as shown in Figure 2, which includes:

① Use mobile activated carbon to catalyze the reaction between hydrogen peroxide and dyes to increase the decolorization speed;

The pure hydrogen peroxide decolorization reaction lasts for more than 1 day, which cannot meet the processing requirements. Therefore, activated carbon is specially added as a reaction catalyst to increase the OH free radicals in hydrogen peroxide to accelerate the decolorization reaction. However, bubbles will be generated during the reaction and it is easy to stay in the active state The contact between the carbons reduces the activated carbon, prevents the decolorization reaction, and affects the decolorization speed. The specially designed agitation device increases the movement of the activated carbon, allowing the bubbles to move out quickly, and effectively improves the reaction speed. The decolorization reaction can be completed in about 8 hours by using activated carbon alone. time is still off There is a need for further improvement;

② Increase the reaction speed of hydrogen peroxide and dyes by increasing the temperature;

The higher the temperature, the faster the reaction effect of hydrogen peroxide, and the relative increase in hydrogen peroxide and energy consumption, so special tests for different temperature reaction requirements are carried out;

③Track the decolorization reaction process by analyzing the concentration of hydrogen peroxide;

Hydrogen peroxide is used for decolorization of recycled dye liquor. The effect of the reaction can be tracked through the detection and tracking of hydrogen peroxide concentration. When hydrogen peroxide is added, the concentration of hydrogen peroxide rises. If the concentration of hydrogen peroxide is not maintained, the decolorization efficiency will increase and the cost of decolorization will be low. Use optimized concentration control to deal with decolorization Reaction, in order to achieve low-cost operation, it is best to deal with the reaction demand and input, and zero residue is the best. To reduce the consumption of hydrogen peroxide, it must be achieved through concentration control;

④ Use the color analyzer to track the effect of decolorization reaction and the basis for dosage control;

During the operation of the decolorization reaction, the color in the water will change. The decolorization reaction path can be known through the color change. Finally, the hydrogen peroxide dosage requirement for each color reaction can be established through the operating experience data. How much hydrogen peroxide is required for treatment? How long is the reaction time? What color will it be? It can clearly track the process, solve the problem of manual operation judgment, and realize the artificial intelligence decolorization operation plan;

⑤ Use reactive carbon to absorb and recover the reactive impurities in the dye solution to ensure the quality of recovered brine;

Activated carbon is a catalytic catalyst, but it is also a good material for impurity adsorption. Medium activated carbon can absorb the decolorized impurities and move them out of the water, so that the quality of the recovered brine is better. When the activated carbon absorbs more, the catalytic effect will become worse. Tracking through the reaction time, when the efficiency drops, it needs to be decolorized after the decolorization is completed. Renews the activated carbon, which can be recycled back into the process.

(5) Utilize the concentration device to concentrate and recover the brine to reach the brine concentration that meets the dyeing requirements and distilled water to be used in the dyeing process;

The recovered brine contains washing water, and its concentration is much lower than the brine concentration required for dyeing. The brine reuse needs to be further concentrated. The recovered brine can be concentrated through MVR (mechanical vapor recompression) concentration equipment, so that the concentrated brine concentration can be used in the dyeing process. The higher the concentrated concentration, the higher the cost required to meet the process requirements. Distilled water can be used in the dyeing process like distilled water;

(6) Use the online detection brine concentration meter and color detector as the verification tool for the control condition of waste dyeing liquid treatment and reuse;

Batch operation is used to control the decolorization treatment steps to ensure the quality of recycling.

In summary, the technical solution of the present application has the following outstanding technical effects:

(1) Electrocoagulation can greatly reduce the chroma effect by about 90~95%. After treatment, the low chroma recovery dye solution can be obtained by filtration. The original waste dye solution can have tens of thousands of chroma values, and its chroma value after treatment Reduced to below 5000;

(2) Through the above hydrogen peroxide deep oxidation technology, the ideal reaction temperature is between 35 and 80°C, and the chromaticity is below 5000, and the decolorization reaction time can be shortened to 0.2 to 3 hours. For each ton of recycled dye liquor with a chroma of 800~4000 chroma, the amount of hydrogen peroxide used is 0.8~4kg to complete the decolorization;

(3) The concentration and color of the waste dyeing liquid salt change quite a lot. Through the measurement of the concentration of brine and the acquisition of color, the concentration and color data of the salt water of the waste dyeing liquid are obtained for comparative analysis. Different conditions will be required. The change of the salt content of the waste dyeing liquid can be cleared through the salt water concentration meter, and the color type and chroma of the waste dyeing liquid can be cleared through the color detector, which can make the treatment more clear; collect the reaction materials during the treatment process, and analyze the optimization The treatment plan can realize a more effective treatment plan. Through processing experience data, it is possible to establish an AI control operation database for waste dyeing liquid treatment in the factory, effectively improve the automation of waste dyeing treatment feeding and control condition setting, and achieve automatic operation goals; for brine reuse On the other hand, using a brine concentration meter to carry out the deployment and measurement of brine reuse can meet the requirements of the dyeing process, and can reduce the concentration of recovered brine and improve the efficiency of treatment and reuse;

(4) The decolorization treatment will have different salt content due to different colors, control conditions and hydrogen peroxide dosage will also be different, which cannot be overcome by consistency conditions. Therefore, the decolorization reaction is specially designed as a batch reaction to increase the flexibility of the reaction operation and solve different reaction conditions. To ensure the consistency of treatment effect and recycling quality.

10: Electrocoagulation capture reaction system

20: Decolorization reaction system

30: Concentrated distillation system

11: waste dye solution

12: Acid dosing device

13: Coagulant dosing device

14: Compressed air

15: Sludge

16: Recycling dye solution

18: Recycling dye liquor filter

19: Plate and frame filter press

21: Activated carbon filter

22: Remove the activated carbon

23:Activated carbon inlet

24: Color detector

25: Hydrogen peroxide detector

26: Hydrogen peroxide dosing device

27: Decolorization sampling device

28: Recovery of brine

29: Recycled brine screening program

31:MVR enrichment equipment

32: Salt water concentration meter

33: Salt water outlet

34: Distilled water outlet

35: concentrated brine

36: distilled water

E10: Electrocoagulation device

G10: Blower

T10: waste dye solution collection tank

T11: Electrocoagulation reaction tank

T12: Aeration tank

T13: Neutralization reaction tank

T14: static settling tank

T15: Recovery Dye Tank

T16: Sludge Thickening Tank

T21: Decolorization reaction tank

T22: Recovery Sink

T31: Distilled water tank

T32: Salt water tank

H: insulation heater

M10: neutralizing mixer

M20: Decolorization Mixer

P10: Waste dye pump

P11: Aeration pump

P12: Recovery filter pump

P13: Sludge filter pump

P14: Filtrate pump

P20: return pump

P21: Decolorization output filter pump

P22: Recovery water pump

P31: Distilled water pump

P32: Brine pump

SV10: waste dyeing solution valve

SV11: Electrocoagulation output valve

SV12: acid output valve

SV13: Coagulant output valve

SV14: neutralization output valve

SV15: Recycling dye solution valve

SV16: Sludge outlet valve

SV17: Filter and slag removal valve

SV18: Filter dye liquor valve

SV21: Activated carbon outlet control valve

SV22: Recycled water filter valve

SV25: Recovery brine output valve

SV26: Hydrogen peroxide dosing valve

Fig. 1, a kind of cotton dyeing waste dye liquor processing and recycling method art roadmap

Figure 2. Composition diagram of hydrogen peroxide deep oxidation method

Figure 3. A specific implementation procedure diagram of a cotton dyeing waste treatment and reuse method and system

Figure 4. A diagram of a cotton dyeing waste treatment and reuse system

Figure 5. Structural diagram of a cotton dyeing waste treatment and reuse system

A kind of implementation program of cotton dyeing waste dyeing liquor treatment recycling method, as shown in Figure 2, its concrete procedure comprises:

(1) Waste dye liquor diversion collection procedures;

The waste dyeing liquid discharged from the cotton dyeing equipment is separately collected and processed in a centralized manner. The components of the waste dyeing liquid include dyes, leveling agents, dyeing accelerators, color fixing agents and water. After mixing and collecting, the color will vary according to the requirements of the dyeing process. The dyeing accelerator generally uses sodium sulfate or sodium chloride, the color fixing agent is sodium carbonate, and there are no other raw materials, and the ingredients are relatively simple;

(2) Electrocoagulation capture program;

Electrocoagulation is used to treat waste dyeing liquid. Electrocoagulation has the functions of electrolysis, capture and coagulation. The related impurities of soluble and insoluble substances in waste dyeing liquid are captured through the release of iron ions. Leveling agents and dyes can capture and settle. , and retain the ingredients of dye accelerator and color fixing agent;

(3) Air flotation and condensation procedures;

The waste dye solution after electrocoagulation is further introduced into a large amount of air through the blower, so that the divalent iron ion Fe2+ released by the electrode is converted into trivalent Fe3+ iron ion to obtain an effective sedimentation function, so that the iron ion can be precipitated and insoluble in water, which can avoid post-treatment Iron ion residue;

(4) neutralization coagulation procedure;

Through the neutralization of acid and alkali, the sodium carbonate in the waste dyeing liquid is converted into sodium sulfate or sodium chloride, so that the salt in the water can form a single salt and be recycled to the process, and further use the coagulant input to make the impurities in the waste dyeing liquid easier to combine , forming larger molecules that can settle rapidly;

(5) Static settlement procedure;

Let the waste dyeing liquid stand still after neutralization and coagulation, and let the pollutants in the water combine and precipitate into sludge;

(6) Filtration removal procedure;

Use the recycling dye solution screening program to filter the waste dye solution after standing still to obtain the recycled dye solution. The impurities in the sludge part will stay on the plate and frame filter press and be removed. The filtered recycled water can remove about 95% dyes, which can reduce subsequent costs;

(7) Oxidative decolorization procedure;

The recovered dye liquor is further applied to the hydrogen peroxide deep oxidation technology, and the hydrogen peroxide is catalyzed by activated carbon to decompose and decolorize all the dyes;

(8) Decolorization inspection procedure;

The decolorization inspection program is the core of decolorization control. Through the hydrogen peroxide detector and color detector, you can clearly understand the decolorization operation status, the amount of hydrogen peroxide input and the timing of input to fully control the decolorization effect. When the decolorization is not complete, you need to go back to the oxidation program. When the standard is reached, it is possible to enter the next program operation;

(9) Filtration and separation procedures;

When the oxidation decolorization procedure is completed and the decolorization inspection procedure is confirmed, the recovered dye solution in the decolorization reaction tank can be further filtered and separated, and the activated carbon in the water can be removed to obtain transparent and colorless recovered water;

(10) Concentrated distillation procedure;

Concentrate the transparent and colorless recovered water with brine to increase the concentration of brine to the concentration required in the dyeing process, and introduce the concentrated distilled water into the distilled water tank to wait for the supply of cotton dyeing equipment;

(11) Salt concentration testing procedure;

The concentrated brine is further inspected with a brine concentration meter. When the concentration reaches the required concentration, the concentrated brine is introduced into the concentrated brine recovery tank for storage, and waits for the application of cotton dyeing equipment.

Through the above-mentioned program, the waste dyeing liquid treatment and reuse method of cotton dyeing can be realized, and the waste dyeing liquid recycling target can be easily achieved. In order to realize the above method, a waste dyeing liquid treatment and reuse system has been specially established, as shown in Figure 4 and Figure 5. content include:

(1) Electrocoagulation capture treatment system;

10 The electrocoagulation capture treatment system consists of T10 waste dyeing liquid collection tank, T11 electrocoagulation reaction tank, T12 aeration tank, T13 neutralization reaction tank, T14 static settling tank, T16 sludge concentration tank, 18 recycling dye solution screening Program, T15 recovery dye solution tank and 19 plate and frame filter press devices; the waste dye solution discharged from cotton dyeing equipment is collected through the T10 waste dye solution collection tank, and the T10 waste dye solution collection tank is passed through the P10 waste dye solution pump and SV10 waste dye solution The dyeing liquid valve is connected with the T11 electrocoagulation reaction tank, and the waste dyeing liquid can be introduced into the electrocoagulation equipment for electrocoagulation operation. The T11 electrocoagulation reaction tank is connected with the T12 aeration tank through the SV11 electrocoagulation output valve, which can discharge the waste dyeing after electrocoagulation. The liquid is introduced into the T12 aeration tank, and an aeration device is installed under the T12 aeration tank 14 compressed air can be introduced through the G10 blower to make the waste dyeing liquid agitate and oxidize and condense. The T12 aeration tank is connected to the T13 neutralization reaction tank through the P11 aeration pump, and the aerated waste dyeing liquid can be introduced into the T13 for neutralization. Reaction tank, T13 neutralization reaction tank is equipped with M10 neutralization mixer, 12 acid dosing device and SV12 acid output valve, 13 coagulant dosing device and SV13 coagulant output valve device, which can aerate waste Stir and neutralize the dye solution, start 12 acid dosing device and SV12 acid output valve, introduce acid to neutralize sodium carbonate in the waste dye solution, convert it into dye accelerator, start 13 coagulant dosing after neutralization Device and SV13 coagulant output valve, introduce coagulant into the neutralized waste dye solution, T13 neutralization reaction tank is connected with T14 static settling tank through SV14 neutralization output valve, can introduce the waste dye solution after neutralization reaction T14 static settling tank for coagulation and sedimentation to convert the leveling agent, dyes and impurities in the waste dyeing liquid into sludge for static settling. The side of T14 static settling tank passes through the P12 recovery filter pump and the 18 recovery dye liquid screening program , The exit of the 18 recovery dye solution screening program is connected to the T15 recovery dye solution tank through the SV18 filter dye solution valve, the T14 static settling tank is connected to the T16 sludge concentration tank through the SV16 sludge outlet valve, and the 18 recovery dye solution screening program The SV17 filter deslagging valve is connected to the T16 sludge thickening tank, and the T16 sludge thickening tank is connected to the 19 plate and frame filter press through the P13 sludge filter pump, which can filter out 15 sludge, and the filtered water can use the P14 filtrate The pump is connected to the T15 recovery dye solution tank, and the T15 recovery dye solution tank is connected to the 20 decolorization reaction system through the SV15 recovery dye solution valve;

(2) Decolorization reaction system;

20 Decolorization reaction system is composed of T21 decolorization reaction tank, 21 activated carbon screening program, 29 recovery salt water screening program, 26 hydrogen peroxide dosing device, 27 decolorization sampling device and T22 recovery water tank; T21 decolorization reaction tank recovers dye liquor through SV15 Valve and front section 10 The T15 recovery dye solution tank of the electrocoagulation capture reaction system is connected to receive 16 recovered dye solutions treated by the electrocoagulation capture reaction system, and the SV21 activated carbon outlet control valve is installed under the T21 decolorization reaction tank to connect with the 21 activated carbon screening program Activated carbon can be filtered out after use, and the raffinate can be led back to the T21 decolorization reaction tank through the P20 reflux pump for decolorization reaction. There is a H constant temperature heater on the side of the T21 decolorization reaction tank to maintain the reaction temperature, and a cover on the top to reduce the temperature. Heat loss, there are 23 activated carbon input ports, M20 decolorization mixer, 26 hydrogen peroxide dosing device, 27 decolorization sampling device on the top, so that 16 recovered dye liquor can undergo decolorization reaction, and there is an outlet on the side of T21 decolorization reaction tank, which is output through P21 decolorization The filter pump is connected to the 29 recovered brine screening program, and the outlet of the screening program is connected to the T22 recovery tank through the SV25 recovered brine output valve, and the 28 recovered brine is introduced into the T22 recovery tank, and the back end is connected to the 30 concentrated distillation system; 26 hydrogen peroxide dosing device Located above the T21 decolorization reaction tank, the 26 hydrogen peroxide dosing device introduces the amount of hydrogen peroxide into the T21 decolorization reaction tank through the SV26 hydrogen peroxide dosing valve, and the 27 decolorization sampling device can extract the dye liquor from the T21 decolorization reaction tank, and pass through the 25 hydrogen peroxide detector and 24 The color detector flows back into the T21 decolorization reaction tank, and the residual amount of hydrogen peroxide is known through the 25 hydrogen peroxide detector, and the decolorization status of the recovered dye solution is checked through the 24 color detector to check the color change of the reaction process. The 24 color detector can Use digital cameras, digital cameras or spectrometers to obtain the color of wastewater, and track the color change path of waste dyeing liquid treatment;

(3) concentrated distillation system;

The 30 concentrated distillation system is composed of 31 MVR concentrated equipment, T31 distilled water tank and T32 brine tank; the front section is introduced into the 31 MVR concentrated equipment through the P22 recovery water pump, and the 31 MVR concentrated equipment has a 33 brine outlet to lead 35 concentrated brine to the T32 brine tank. It can be transported to the dyeing machine through the P32 salt water pump. The 31 MVR concentration equipment also has a 34 distilled water outlet, which can lead the 36 distilled water to the T31 distilled water tank, and can be transported to the dyeing machine through the P31 distilled water pump.

Through 10 electrocoagulation capture treatment systems, 20 decolorization reaction systems and 30 concentration distillation systems, the waste dyeing liquor treatment and reuse system can be formed.

The working principle of the waste dyeing liquid recycling system of this application is as follows: the waste dyeing liquid is diverted from the dyeing process of the cotton dyeing equipment, collected through the T10 waste dyeing liquid collection tank, and further uses the P10 waste dyeing liquid pump to pass 11 waste dyeing liquids through the SV10 waste dyeing liquid The valve is introduced into the T11 electrocoagulation reaction tank for electrocoagulation operation. The E10 electrocoagulation device is used for electrocoagulation operation in the T11 electrocoagulation reaction tank. After the electrocoagulation operation, it is introduced into the T12 aeration tank through the SV11 electrocoagulation output valve, and then the G10 blower is used to introduce 14 compressed air for oxidation, so that the ferrous ions Fe2+ can be converted into ferric ions Fe3+ that can settle, After 1~2 hours of conversion, start the P11 aeration pump again, introduce the waste dyeing liquid into the T3 neutralization reaction tank, carry out neutralization and flocculant addition operations, start the M10 neutralization mixer to stir and measure the waste dyeing liquid before neutralization The PH value of the liquid, and then control the amount of acid added through the PH value, and use the 12 acid dosing device and the SV12 acid output valve to introduce acid for neutralization. After the neutralization is completed, the next step is to add coagulant. Drug device and SV13 coagulant output valve, introduce the coagulant into the T13 neutralization reaction tank for coagulation operation, after the coagulation is completed, further open the SV14 neutralization output valve, and introduce the waste dye solution in the T13 neutralization reaction tank into T14 Stand still in the settling tank for static settling operation, after 1~3 hours of standing still, let most of the dyes, leveling agents and impurities in the waste dyeing liquid combine and precipitate to form sludge; Turn on the P12 recovery filter pump, introduce the waste dye solution into the 18 recovery dye solution screening program to block the sludge impurities, and connect the outlet to the SV18 filter solution valve to obtain 16 recovery dye solution, and then introduce the T15 recovery solution tank to complete the electrocoagulation capture Reaction operation; most of the sludge in the static settling tank of T14 will settle to the bottom. When the amount of sludge accumulates, open the SV16 sludge outlet valve below to introduce the sludge into the T16 sludge thickening tank for temporary storage. The above 18 recycling dye liquid screens The slag discharge outlet of the inspection program, through the SV17 filter and slag removal valve, the sludge impurities intercepted by the 18 recycled dyeing liquid screening program can be introduced into the T16 sludge thickening tank. When the T16 sludge thickening tank has a large volume, the P13 sludge filter pump can be used The sludge from the T16 sludge concentration tank is introduced into the 19 plate and frame filter press, and the 15 sludge is pressed out, and the filtrate can be introduced into the T15 recovery dyeing tank through the P14 filtrate pump for reuse. Next, the decolorization reaction operation is carried out. Use the SV15 recovery dye liquor valve to introduce the recycled dye liquor into the T21 decolorization reaction tank. The T21 decolorization reaction tank needs to be filled with activated carbon in advance, and can be put into the T21 decolorization reaction tank through the 23 activated carbon inlet. About 0.5-5kg/T is used as a catalyst. After the recovered dyeing solution is filled, turn on the M20 decolorization mixer to further heat and keep the recovered dyeing solution, and keep the recovered dyeing solution at 35-80°C through the H insulation heater, and wait for the heating to complete Then turn on the 27 decolorization sampling device and further use the 24 color detector to understand the color information of the recovered dye solution, and further use the color dosing database to obtain the oxidant input information. Dosage, reaction time, and color information after the reaction is completed; use the 25 hydrogen peroxide detector to detect the ratio of the input hydrogen peroxide, and you can get the decolorization reaction. After the hydrogen peroxide detector judges that the reaction is complete, that is, when the hydrogen peroxide drops to the set value, then carry out 24 colors Detector, look at the decolorization effect, and you can clearly see the oxidant input in the early stage by sampling the color Whether it is within the control range, using the information of the color dosing database again to carry out the decolorization reaction program, it is necessary to put in the oxidant reaction many times until the setting requirements are met, and then the decolorization program can be determined to be completed; the amount of hydrogen peroxide and the reaction time speed can be determined. Know whether the catalytic ability of the activated carbon is normal. When the activated carbon absorbs too many impurities, the reaction rate will be affected. The activated carbon will need to be renewed to ensure the normal operation of the decolorization reaction program; when the decolorization is completed, turn on the P21 decolorization output filter pump and the SV22 recovery water The filter valve is used to introduce the 16 recovered dye solution into the T22 recovery water tank after the decolorization is completed, and filter through the 29 recovery brine screening program, and the filtered 28 recovery brine is introduced into the T22 recovery water tank through the SV25 recovery brine output valve, and then the next decolorization reaction is carried out; When the catalytic ability of the activated carbon decreases and the decolorization time is prolonged, it is necessary to update the activated carbon operation. After the decolorization is completed and the recycled water is filtered, after further cleaning the recycled water screening program, open the SV21 activated carbon outlet under the T21 decolorization reaction tank Control valve, introduce the residual water and activated carbon in the T21 decolorization reaction tank into the 21 activated carbon screening program, close the SV21 activated carbon outlet control valve, remove the activated carbon after filtration, and further guide the excess water back through the P20 reflux pump In the T21 decolorization reaction tank, new activated carbon is introduced from the 23 activated carbon input port, and the activated carbon renewal operation is completed. The 28 brine that flows into the T22 recovery tank is introduced into the 31 MVR concentration equipment through the P22 recovery water pump for concentration operation, and 35 concentrated brine and 36 distilled water can be obtained, which are introduced into the T32 brine tank through the 33 brine outlet, and the 32 brine concentration in the brine tank can be passed Measure the concentration of 35 concentrated brine, and further use the P32 brine pump to lead back to the dyeing machine to provide the dyeing process for deployment, while the 36 distilled water is led to the T31 distilled water tank through the 34 distilled water outlet, and the P31 distilled water pump can be used to lead the 36 distilled water to the dyeing machine to provide dyeing process utilization.

Claims (3)

A method for treating and recycling cotton dyeing waste liquid, which includes: (1) collecting the waste dye liquid by diversion; (2) using an electrocoagulation system to treat insoluble and dissolved pollutants in the waste dye liquid, retaining the dye accelerator and color fixation (3) use acid to neutralize soda ash in the waste dye solution, and convert it into a dye accelerator; (4) use hydrogen peroxide deep oxidation technology to decompose and recover the residual dye in the dye solution to obtain transparent and colorless recovered brine; (5) Use the concentrator to concentrate and recover the brine to achieve the brine concentration that meets the dyeing requirements and the purpose of reusing the distilled water in the dyeing process; (6) Use the online detection brine concentration meter and color detector as a verification tool for the control conditions of waste dyeing liquid treatment and reuse; ( 7) Use batch operation to control the decolorization treatment steps to ensure the quality of recycling. The method for treating and recycling cotton dyeing waste dyeing liquor as described in claim item 1, wherein the hydrogen peroxide deep oxidation technology includes: (1) using mobile activated carbon to catalyze the reaction between hydrogen peroxide and dyes to increase the decolorization speed; Dye reaction speed; (3) Use hydrogen peroxide concentration analysis to track the decolorization reaction process; (4) Use color analyzer to track the decolorization reaction effect and dosage control basis; (5) Use activated carbon to absorb and recover the reaction impurities in the dye solution to ensure the quality of recovered brine . A waste dyeing liquor treatment and recycling system, comprising: (1) Electrocoagulation capture treatment system, which is composed of waste dyeing liquid collection tank, electrocoagulation reaction tank, aeration tank, neutralization reaction tank, static settling tank, sludge concentration tank, recovery dyeing liquid filter, recovery dyeing It is composed of a liquid tank and a plate and frame filter press device, in which the waste dyeing liquid discharged from the cotton dyeing equipment is collected through the waste dyeing liquid collection tank, and the waste dyeing liquid collection tank is connected with the electroflocculation reaction tank through the waste dyeing liquid pump and the waste dyeing liquid valve , the waste dyeing solution can be introduced into the electrocoagulation equipment for electrocoagulation operation, the electrocoagulation reaction tank is connected with the aeration tank through the electrocoagulation output valve, and the waste dyeing solution after electrocoagulation can be introduced into the aeration tank, and there is an aeration tank under the aeration tank The aeration device can introduce compressed air through the blower to make the waste dyeing liquid produce agitation and oxidation condensation. A neutralization mixer, an acid dosing device, an acid output valve, a coagulant dosing device and a coagulant output valve are installed above the reaction tank, which can stir and neutralize the aerated waste dyeing liquid, and start Acid dosing device and acid output valve, introduce acid to neutralize sodium carbonate in waste dyeing liquid, convert it into dye accelerator, start coagulant dosing device and coagulant output valve after neutralization, introduce coagulant in In the neutralization waste dyeing liquid, the neutralization reaction tank is connected with the static settling tank through the neutralization output valve, and the waste dyeing liquid after the neutralization reaction can be introduced into the static settling tank for coagulation and sedimentation, and the leveling agent in the waste dyeing liquid , Dye and impurity conversion sludge is left to settle, the side of the settling tank passes through the recovery filter pump and the recovery dye solution filter, the outlet of the recovery dye solution filter is connected to the recovery dye solution tank through the filter dye solution valve, and the settling tank is left static The lower part is connected to the sludge thickening tank through the sludge outlet valve, the recycled dyeing liquid filter is connected to the sludge thickening tank through the filter deslagging valve, and the sludge thickening tank is connected to the plate and frame filter press through the sludge filter pump, and the sewage The mud is filtered out, and the filtered water can be connected to the recovery dye solution tank by the filtrate pump, and the recovery dye solution tank is connected to the decolorization reaction system through the recovery dye solution valve; (2) The decolorization reaction system is composed of a decolorization reaction tank, an activated carbon filter, a recovery brine filter, a hydrogen peroxide dosing device, a decolorization sampling device and a recovery water tank. The recovery dye solution tank of the capture reaction system is connected to receive the recovered dye solution treated by the electrocoagulation capture reaction system. The activated carbon outlet control valve is installed under the decolorization reaction tank and connected to the activated carbon filter to filter out the activated carbon after use. The residual liquid can be led back to the decolorization reaction tank through the reflux pump for decolorization reaction. The side of the decolorization reaction tank is equipped with a constant temperature heater to maintain the reaction temperature, and the top is equipped with a cover to reduce heat loss. The upper part is equipped with an activated carbon input port, a decolorization mixer, Hydrogen peroxide dosing device and decolorization sampling device allow the recovered dye liquor to undergo decolorization reaction. There is an outlet on the side of the decolorization reaction tank, which is connected to the recovery brine filter through the decolorization output filter pump, and the filter outlet is connected to the recovery water tank through the recovery brine output valve , the recovered brine is introduced into the recovery tank, and its rear end is connected to the concentrated distillation system. The hydrogen peroxide dosing device is installed above the decolorization reaction tank. The hydrogen peroxide dosing device introduces the amount of hydrogen peroxide into the decolorization reaction tank through the hydrogen peroxide dosing valve. The decolorization sampling device can extract The dye liquor is recovered in the reaction tank, and then flows back into the decolorization reaction tank through the hydrogen peroxide detector and the color detector. The residual amount of hydrogen peroxide can be known through the hydrogen peroxide detector, and the decolorization status of the recovered dye liquor can be checked through the color detector and the amount of hydrogen peroxide, so that the color of the reaction process can be clearly understood change, the color detector can be a digital video camera, digital camera or spectrometer to obtain the color of wastewater, and track the color change path of waste dyeing liquid treatment; (3) Concentration distillation system, which is composed of MVR concentration equipment, distilled water tank and salt The composition of the water tank, the front section is introduced into the MVR concentration equipment through the recovery water pump, and the MVR concentration equipment has a brine outlet to lead the concentrated brine to the brine tank, which can be transported to the dyeing machine for reuse through the brine pump, and the MVR concentration The equipment also has a distilled water outlet, which can lead the distilled water to the distilled water tank, and can be transported to the dyeing machine for reuse through the distilled water pump.

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