System and method for recycling dyeing brine

Abstract

The invention discloses a dyeing brine recycling system and method. The system comprises an adjusting tank, a decarburization tank, an electrochemical reactor, a dechlorination tank, a tail gas absorption tower and a neutralization tank, a dyeing brine outlet of the adjusting tank is connected to a dyeing brine inlet of the decarburization tank; a dyeing brine outlet of the decarburization tank is connected to a dyeing brine inlet of the electrochemical reactor; a dyeing brine outlet of the electrochemical reactor is connected to a dyeing brine inlet of the dechlorination tank; a tail gas outlet of the dechlorination tank is connected to a tail gas inlet of the tail gas absorption tower; a dyeing brine outlet of the dechlorination tank is connected to a dyeing brine inlet of the neutralization tank; and the treated dyeing saline water outlet of the neutralization tank outputs dyeing saline water for reuse. The dyeing brine recycling system and method have the advantages of being low in operation cost, easy to operate, free of pollutants and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection and resource recovery, and in particular relates to a system and method for recycling dyed brine. Background Art

[0002] A large amount of sodium chloride is usually used to promote dyeing in the printing and dyeing process. At the same time, the COD content in the dyeing wastewater is also high, so it is very economically and environmentally beneficial to treat and reuse it. At present, the reuse methods of dyeing wastewater with a high sodium chloride content (also known as dyeing brine) mainly include: extraction method, membrane separation method and Fenton method. However, the operating costs of these methods are usually high, the process flow is complicated, and pollutants such as concentrated water will be produced.

[0003] Therefore, developing a dye brine recycling system with low operating cost, simple operation and no pollutants has become one of the urgent problems to be solved in this field. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a system and method for recycling dyed brine. The system and method for recycling dyed brine have the advantages of low operating cost, simple operation and no pollutants.

[0005] In order to achieve the above-mentioned object, the first aspect of the present invention provides a dyed brine reuse system, which comprises: a regulating tank, a decarbonization tank, an electrochemical reactor, a dechlorination tank, a tail gas absorption tower and a neutralization tank;

[0006] The regulating tank is at least provided with a dyed brine outlet, the decarbonization tank is at least provided with a dyed brine inlet, an acid inlet, a first aeration component and a dyed brine outlet, the electrochemical reactor is at least provided with a dyed brine inlet and a dyed brine outlet, the dechlorination tank is at least provided with a dyed brine inlet, a second aeration component, a tail gas outlet and a dyed brine outlet, the tail gas absorption tower is at least provided with a tail gas inlet, an absorption liquid inlet, an absorption liquid outlet and a purified tail gas outlet, and the neutralization tank is at least provided with a dyed brine inlet, an alkali inlet and a treated dyed brine outlet;

[0007] The dyed brine outlet of the regulating tank is connected to the dyed brine inlet of the decarbonization tank; the dyed brine outlet of the decarbonization tank is connected to the dyed brine inlet of the electrochemical reactor; the dyed brine outlet of the electrochemical reactor is connected to the dyed brine inlet of the dechlorination tank; the tail gas outlet of the dechlorination tank is connected to the tail gas inlet of the tail gas absorption tower; the dyed brine outlet of the dechlorination tank is connected to the dyed brine inlet of the neutralization tank; the treated dyed brine outlet of the neutralization tank outputs the dyed brine for reuse.

[0008] According to a specific embodiment of the present invention, preferably, the regulating tank is also provided with a dyed brine circulation outlet and a dyed brine circulation inlet, the dyed brine circulation outlet is connected to the absorption liquid inlet of the tail gas absorption tower, and the absorption liquid outlet of the tail gas absorption tower is connected to the dyed brine circulation inlet, for using the dyed brine in the regulating tank as the absorption liquid to absorb the chlorine in the tail gas to obtain the purified tail gas, and the absorption liquid after absorbing the chlorine in the tail gas is circulated to the regulating tank. More preferably, a circulation pump is provided on the pipeline connecting the dyed brine circulation outlet and the absorption liquid inlet of the tail gas absorption tower.

[0009] According to a specific embodiment of the present invention, preferably, the regulating tank includes a dyed brine storage tank. More preferably, a stirring assembly is provided in the regulating tank. The regulating tank is used to uniformly homogenize the water quality of the dyed brine, and the water quality can be better uniformed by further providing a stirring assembly.

[0010] According to a specific embodiment of the present invention, preferably, a water inlet pump is provided on the pipeline connecting the dyed brine outlet of the regulating tank and the dyed brine inlet of the decarbonization tank.

[0011] According to a specific embodiment of the present invention, preferably, the acid inlet of the decarbonization tank is connected to an acid storage tank, and a first dosing pump is provided on the pipeline connecting the acid inlet of the decarbonization tank and the acid storage tank. The acid inlet of the decarbonization tank, the acid storage tank and the first dosing pump are used to add acid to the dyed brine in the decarbonization tank to adjust the pH value of the dyed brine to 2.0-4.0. The acid may include hydrochloric acid and / or sulfuric acid, etc.

[0012] According to a specific embodiment of the present invention, preferably, the first aeration assembly of the decarbonization tank at least comprises an aeration pipe, and the aeration pipe is connected to an air source for blowing air into the decarbonization tank from the bottom of the decarbonization tank.

[0013] The present invention provides a decarbonization pool for adding acid to adjust the pH value of the dyed brine to 2.0-4.0, and for blowing air into the dyed brine for continuous aeration, thereby removing carbonate ions and blowing out carbon dioxide, thereby achieving decarbonization of the dyed brine, and at the same time facilitating the generation of ozone, hydroxyl radicals, hypochlorous acid, chlorine radicals and chlorine gas in the electrochemical decolorization process, and improving its decolorization efficiency.

[0014] According to a specific embodiment of the present invention, preferably, the electrochemical reactor comprises at least an electrolytic cell, an anode and a cathode. More preferably, the electrolytic cell is a diaphragmless electrolytic cell. More preferably, the anode comprises a metal oxide electrode, a glassy carbon electrode, a platinum electrode, a graphite electrode or a BDD electrode, etc., and the cathode comprises a pure metal electrode, a carbon material electrode or an alloy electrode, etc. Among them, the pure metal electrode may include, for example, copper, lead, zinc, titanium, or a stainless steel electrode, etc.

[0015] The present invention can use the dyed salt water after decarbonization as an electrolyte by arranging an electrochemical reactor at the rear of the decarbonization tank, thereby realizing the decolorization of the dyed salt water after decarbonization. Specifically, in the process of electrochemical decolorization, strongly oxidizing ozone, hydroxyl radicals, hypochlorous acid, chlorine radicals and chlorine gas can be generated, which can react with the chromophoric groups in the dye molecules to break the chemical bonds of the dye molecules and destroy their chromophoric structures. Moreover, the anode itself in the electrochemical process also has a direct oxidation effect, and the active sites on the surface of the anode material can directly react with the dye molecules in the dyed salt water.

[0016] According to a specific embodiment of the present invention, preferably, the second aeration assembly of the dechlorination tank at least comprises an aeration pipe, and the aeration pipe is connected to an air source for blowing air from the bottom of the dechlorination tank into the dechlorination tank.

[0017] The present invention arranges a dechlorination tank behind the electrochemical reactor and blows air into the decolorized dyed salt water for continuous aeration, thereby enabling chlorine dissolved in the dyed salt water to volatilize from the water, thereby achieving dechlorination of the decolorized dyed salt water.

[0018] According to a specific embodiment of the present invention, preferably, the tail gas inlet and the absorption liquid outlet of the tail gas absorption tower are arranged at the lower part of the tail gas absorption tower, the absorption liquid inlet and the purified tail gas outlet of the tail gas absorption tower are arranged at the upper part of the tail gas absorption tower, and a spray assembly is arranged in the tail gas absorption tower, and the spray assembly is connected to the absorption liquid inlet, and is used to contact the absorption liquid with the tail gas in countercurrent by spraying to absorb the chlorine therein, so as to obtain the purified tail gas. More preferably, a purified tail gas fan is arranged on the pipeline connected to the purified tail gas outlet of the tail gas absorption tower.

[0019] The present invention further uses the dyed brine in the regulating tank as an absorption liquid, and absorbs chlorine in the tail gas in a spraying manner. The chlorine in the tail gas reacts with the dye in the dyed brine, and the spraying method can improve the mass transfer efficiency of the two, thereby removing most or even all of the residual chlorine in the tail gas, achieving safe and pollution-free discharge of the purified tail gas, and at the same time removing part of the dye in the dyed brine, which can reduce the load of subsequent electrochemical decolorization.

[0020] According to a specific embodiment of the present invention, preferably, the alkali inlet of the neutralization tank is connected to an alkali storage tank, and a second dosing pump is provided on the pipeline connecting the alkali inlet of the neutralization tank and the alkali storage tank. The alkali inlet of the neutralization tank, the alkali storage tank and the second dosing pump are used to add alkali to the dyed brine in the neutralization tank to adjust the pH value of the dyed brine to neutral, for example, a pH value of 6.0-7.0. The alkali may include sodium hydroxide, etc. More preferably, a stirring assembly is provided in the neutralization tank.

[0021] The present invention adjusts the pH value of the dechlorinated dyeing salt water to neutral to obtain reusable dyeing salt water. When the dyeing salt water is reused, dyes and alkali can be added to dye fabrics, etc., and the pH value of the dyeing salt water is adjusted to neutral by setting a neutralization tank, so that the stability of the dye added during reuse can be protected and the interference of the acid-base neutralization process on dyeing can be avoided.

[0022] According to a specific embodiment of the present invention, preferably, the system further comprises a reuse tank, which is connected to the treated dyed brine outlet of the neutralization tank. The reuse tank is used to reuse the treated dyed brine.

[0023] A second aspect of the present invention provides a method for recycling dyed brine, the method being carried out using the above-mentioned system for recycling dyed brine, and the method comprising the following steps:

[0024] (1) Allowing dyed brine to enter the regulating tank to even out the water quality;

[0025] (2) then entering the decarbonization tank for decarbonization, adding acid to the decarbonization tank to adjust the pH value of the dyed brine to 2.0-4.0, and blowing air into the decarbonization tank for continuous aeration, the aeration time is 0.5-4h;

[0026] (3) then entering an electrochemical reactor as an electrolyte for decolorization, controlling the electrolysis voltage of the electrochemical reactor to be 2-100 V, the current to be 1-1000 A, the operating temperature to be 10-90° C., and the treatment time to be 0.1-10 h;

[0027] (4) Then, the mixture is placed in a dechlorination tank for dechlorination, and air is blown in for continuous aeration for 2-8 hours to obtain tail gas and dechlorinated dyed brine;

[0028] (5) the tail gas enters a tail gas absorption tower to absorb chlorine therein to obtain purified tail gas;

[0029] (6) The dechlorinated dyeing brine enters a neutralization tank, into which alkali is added to adjust the pH value of the dechlorinated dyeing brine to neutral, thereby obtaining treated dyeing brine.

[0030] According to a specific embodiment of the present invention, preferably, in step (5), the tail gas absorption tower uses the dyed brine in the regulating tank as the absorption liquid, and uses a spraying method to make the absorption liquid contact with the tail gas in countercurrent to absorb the chlorine therein to obtain the purified tail gas, and the absorption liquid after absorbing the chlorine in the tail gas is circulated to the regulating tank.

[0031] The present invention has at least the following beneficial effects:

[0032] The dyed brine recycling system and method of the present invention realizes full reuse of the dyed brine and zero discharge of wastewater. In addition, the present invention realizes the removal of residual chlorine in tail gas and the removal of most dyes in the dyed brine, and the tail gas can be discharged safely. The present invention has the advantages of low operating cost, simple operation, and no pollutants. Moreover, the treated dyed brine obtained by the present invention can be reused and has a good dyeing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the structure of a dyed brine recycling system provided in a specific embodiment of the present invention.

[0034] Description of Figure Numbers:

[0035] 1-regulating tank; 2-decarbonization tank; 201-first aeration component; 3-electrochemical reactor; 4-dechlorination tank; 401-second aeration component; 5-tail gas absorption tower; 501-spraying component; 6-neutralization tank; 7-recycling tank; 8-circulation pump; 9-water inlet pump; 10-acid storage tank; 11-first dosing pump; 12-purified tail gas fan; 13-alkali storage tank; 14-second dosing pump. DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the present invention is now described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0037] It should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0038] In the description of the present invention, it should be noted that the terms “first” and “second” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be a direct connection or an indirect connection through an intermediate medium. It can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the description of the present invention, it should be noted that the terms "comprises", "includes" and / or "contains" when used in this document specify the existence of stated features, integers, steps, components or a combination thereof, but do not exclude the existence or addition of one or more other features, integers, steps, components or a combination thereof.

[0041] In one embodiment of the present invention, the present invention provides a system for recycling dyed brine, such as Figure 1 As shown, it includes: a regulating tank 1, a decarbonization tank 2, an electrochemical reactor 3, a dechlorination tank 4, a tail gas absorption tower 5, a neutralization tank 6 and a reuse tank 7;

[0042] The regulating tank 1 is at least provided with a dyed brine outlet, a dyed brine circulation outlet and a dyed brine circulation inlet, the decarbonization tank 2 is at least provided with a dyed brine inlet, an acid inlet, a first aeration component 201 and a dyed brine outlet, the electrochemical reactor 3 is at least provided with a dyed brine inlet and a dyed brine outlet, the dechlorination tank 4 is at least provided with a dyed brine inlet, a second aeration component 401, a tail gas outlet and a dyed brine outlet, the tail gas absorption tower 5 is at least provided with a tail gas inlet, an absorption liquid inlet, an absorption liquid outlet and a purified tail gas outlet, and the neutralization tank 6 is at least provided with a dyed brine inlet, an alkali inlet and a treated dyed brine outlet;

[0043] The dyed brine outlet of the regulating tank 1 is connected to the dyed brine inlet of the decarbonization tank 2; the dyed brine circulation outlet of the regulating tank 1 is connected to the absorption liquid inlet of the tail gas absorption tower 5, and the absorption liquid outlet of the tail gas absorption tower 5 is connected to the dyed brine circulation inlet of the regulating tank 1, which is used to use the dyed brine in the regulating tank 1 as the absorption liquid to absorb chlorine in the tail gas to obtain purified tail gas, and circulate the absorption liquid after absorbing chlorine in the tail gas to the regulating tank 1; the dyed brine outlet of the decarbonization tank 2 is connected to the dyed brine inlet of the electrochemical reactor 3; the dyed brine outlet of the electrochemical reactor 3 is connected to the dyed brine inlet of the dechlorination tank 4; the tail gas outlet of the dechlorination tank 4 is connected to the tail gas inlet of the tail gas absorption tower 5; the dyed brine outlet of the dechlorination tank 4 is connected to the dyed brine inlet of the neutralization tank 6; the treated dyed brine outlet of the neutralization tank 6 outputs the dyed brine for reuse; the reuse tank 7 is connected to the treated dyed brine outlet of the neutralization tank 6, which is used to reuse the treated dyed brine.

[0044] A circulation pump 8 is provided on the pipeline connecting the dyed brine circulation outlet of the regulating tank 1 and the absorption liquid inlet of the tail gas absorption tower 5 .

[0045] The regulating tank 1 includes a dyeing salt water storage tank. A stirring assembly is provided in the regulating tank 1. The regulating tank 1 is used to uniformly adjust the water quality of the dyeing salt water, and the uniformity of the water quality can be better achieved by providing the stirring assembly.

[0046] A water inlet pump 9 is provided on the pipeline connecting the dyed brine outlet of the regulating tank 1 and the dyed brine inlet of the decarbonization tank 2 .

[0047] The acid inlet of the decarbonization tank 2 is connected to an acid storage tank 10, and a first dosing pump 11 is provided on the pipeline connecting the acid inlet of the decarbonization tank 2 and the acid storage tank 10. The acid inlet of the decarbonization tank 2, the acid storage tank 10 and the first dosing pump 11 are used to add acid to the dyed brine in the decarbonization tank 2 to adjust the pH value of the dyed brine to 2.0-4.0. The acid may include hydrochloric acid and / or sulfuric acid, etc.

[0048] The first aeration assembly 201 of the decarbonization tank 2 at least includes an aeration pipe, and the aeration pipe is connected to an air source for blowing air into the decarbonization tank 2 from the bottom of the decarbonization tank 2 .

[0049] The electrochemical reactor 3 at least comprises an electrolytic cell, an anode and a cathode. The electrolytic cell is a diaphragmless electrolytic cell. The anode comprises a metal oxide electrode, a glassy carbon electrode, a platinum electrode, a graphite electrode or a BDD electrode, etc., and the cathode comprises a pure metal electrode, a carbon material electrode or an alloy electrode, etc. Among them, the pure metal electrode may include, for example, copper, lead, zinc, titanium, or a stainless steel electrode, etc.

[0050] The second aeration assembly 401 of the dechlorination tank 4 at least includes an aeration pipe, and the aeration pipe is connected to an air source for blowing air into the dechlorination tank 4 from the bottom of the dechlorination tank 4 .

[0051] The tail gas inlet and the absorption liquid outlet of the tail gas absorption tower 5 are arranged at the lower part of the tail gas absorption tower 5, the absorption liquid inlet and the purified tail gas outlet of the tail gas absorption tower 5 are arranged at the upper part of the tail gas absorption tower 5, and a spray assembly 501 is arranged in the tail gas absorption tower 5, and the spray assembly 501 is connected with the absorption liquid inlet, and is used to contact the absorption liquid with the tail gas in a countercurrent manner by spraying to absorb the chlorine therein, so as to obtain the purified tail gas. A purified tail gas fan 12 is arranged on the pipeline connected to the purified tail gas outlet of the tail gas absorption tower 5, and is used to discharge the purified tail gas at high altitude.

[0052] The alkali inlet of the neutralization tank 6 is connected to an alkali storage tank 13, and a second dosing pump 14 is provided on the pipeline connecting the alkali inlet of the neutralization tank 6 and the alkali storage tank 13. The alkali inlet of the neutralization tank 6, the alkali storage tank 13 and the second dosing pump 14 are used to add alkali to the dyeing brine in the neutralization tank 6 to adjust the pH value of the dyeing brine to neutral, for example, pH 6.0-7.0. The alkali may include sodium hydroxide, etc. A stirring assembly is provided in the neutralization tank 6.

[0053] In another specific embodiment of the present invention, the present invention provides a method for recycling dyed brine, the method adopts the above-mentioned dyed brine recycling system, and the method comprises the following steps: allowing the dyed brine to enter the regulating tank 1 to uniform the water quality; then entering the decarbonization tank 2 for decarbonization, adding acid to the decarbonization tank 2 to adjust the pH value of the dyed brine to 2.0-4.0, and blowing air for continuous aeration, the aeration time is 0.5-4h; then entering the electrochemical reactor 3 as an electrolyte for decolorization, controlling the electrochemical reactor 3 The dechlorination voltage is 2-100V, the current is 1-1000A, the operating temperature is 10-90℃, and the treatment time is 0.1-10h; then it enters the dechlorination tank 4 for dechlorination, and air is blown in for continuous aeration, and the aeration time is 2-8h to obtain tail gas and dechlorinated dyed brine; the tail gas enters the tail gas absorption tower 5 to absorb the chlorine therein to obtain purified tail gas; the dechlorinated dyed brine enters the neutralization tank 6, and alkali is added to the neutralization tank 6 to adjust the pH value of the dechlorinated dyed brine to neutral to obtain treated dyed brine.

[0054] The dyed brine in the regulating tank 1 has a sodium chloride concentration of 40-110 g / L, a pH value of 9.0-12.0, a chromaticity of 1000-40000 times, and a COD of 2000-8000 mg / L.

[0055] The tail gas absorption tower 5 uses the dyed salt water in the regulating tank 1 as the absorption liquid, and uses a spraying method to contact the absorption liquid with the tail gas in countercurrent to absorb the chlorine therein, so as to obtain the purified tail gas, which can be discharged at high altitude, and the absorption liquid after absorbing the chlorine in the tail gas is circulated to the regulating tank 1. The chlorine content in the purified tail gas is 0.5mg / m 3 the following.

[0056] The treated dyed brine can enter the reuse pool 7 for reuse. The treated dyed brine has a sodium chloride concentration of 50-120 g / L, a pH value of 6.0-7.0, a chromaticity of 50-200 times, a residual chlorine content of 0.1-5 mg / L, and a COD of less than 2500 mg / L.

[0057] Test method:

[0058] pH value of dyeing salt water: measured with a pH meter.

[0059] Sodium chloride concentration and residual chlorine content of dyed brine: Sodium chloride concentration is measured by conductivity meter method, and residual chlorine content is measured by residual chlorine electrode method.

[0060] COD of dyed brine: measured by potassium dichromate method.

[0061] Chroma of dyed salt water: measured by dilution multiple method.

[0062] Total alkalinity of dyed brine: measured by potentiometric titration.

[0063] Fabric dyeing color difference: measured using a colorimeter.

[0064] Chlorine content in tail gas: measured by iodine titration method.

[0065] Example 1

[0066] This embodiment adopts Figure 1 The reuse system of dyed brine shown has a structure as described above. In the present embodiment, the pH value of the dyed brine in the regulating tank 1 is 11.1, the COD is 4500mg / L, the sodium chloride concentration is 100g / L, the chromaticity is 10000 times, and the total alkalinity is 2500mg / L. The dyed brine is made to enter the decarbonization tank 2 for decarbonization, and hydrochloric acid is added to the decarbonization tank 2 to adjust the pH value of the dyed brine to 2.5, and air is blown in for continuous aeration, and the aeration time is 1h. After that, it enters the electrochemical reactor 3 as an electrolyte for decolorization, the electrolytic cell is a diaphragmless electrolytic cell, the anode is a ruthenium iridium electrode, the cathode is a graphite electrode, the electrolysis voltage of the control electrochemical reactor 3 is 6V, the current is 200A, the operating temperature is 60°C, the processing time is 1h, and the decolorized dyed brine is obtained, the chromaticity is 128 times, and the residual chlorine content is 100mg / L. After that, it enters the dechlorination tank 4 for dechlorination, and air is blown in for continuous aeration. The aeration time is 2 hours to obtain the dechlorinated dyed brine, and the remaining chlorine content is 1 mg / L. The tail gas generated in the dechlorination process enters the tail gas absorption tower 5, and the dyed brine in the regulating tank 1 is used as the absorption liquid. The absorption liquid is contacted with the tail gas in countercurrent by spraying to absorb the chlorine therein to obtain the purified tail gas, and the absorption liquid after absorbing the chlorine in the tail gas is circulated to the regulating tank 1. The chlorine content in the purified tail gas is 0.5 mg / m 3 , achieving safe and pollution-free discharge of the purified tail gas. Then the dechlorinated dyeing brine enters the neutralization tank 6, and sodium hydroxide is added to the neutralization tank 6 to adjust the pH value of the dyeing brine to 6.5 to obtain the treated dyeing brine. After that, the treated dyeing brine enters the reuse tank 7. The sodium chloride concentration of the treated dyeing brine is 108g / L, the pH value is 6.5, the chromaticity is 128 times, the residual chlorine content is 1mg / L, and the COD is 2100mg / L.

[0067] The treated dyeing salt water is reused for dyeing, and the dyed fabric is 20-count double pure cotton semi-bleached cloth. A dyeing composition is added to the treated dyeing salt water, and the dyeing composition includes: dye ligenin black and substitute alkali, the amount of dye ligenin black added to the fabric is 7wt%, and the amount of substitute alkali added to the treated dyeing salt water is 4g / L, and no sodium chloride is added. The above fabric is dyed at 60°C for 60 minutes at a bath ratio of 1:10.

[0068] The dyed fabric of this embodiment is compared with the fabric dyed with fresh sodium chloride, and the color difference (△E) is 0.19, which proves that the recycled dyeing salt water of this embodiment has a better dyeing effect, and its dyeing effect and uniform dyeing are both better. Among them, the process of dyeing with fresh sodium chloride includes: preparing a sodium chloride aqueous solution, wherein the sodium chloride concentration is 108g / L, and the pH value is 6.5, adding a dyeing composition thereto, and the dyeing composition includes: a dye ligenin black and a substitute alkali, the amount of the dye ligenin black added to the fabric is 7wt%, and the amount of the substitute alkali added to the sodium chloride aqueous solution is 4g / L; dyeing the above fabric at a bath ratio of 1:10 at 60°C for 60min.

[0069] Example 2

[0070] This embodiment adopts Figure 1 The reuse system of the dyed brine shown has a structure as described above. In the present embodiment, the pH value of the dyed brine in the regulating tank 1 is 10.5, the COD is 3000mg / L, the sodium chloride concentration is 80g / L, the chromaticity is 6000 times, and the total alkalinity is 1300mg / L. The dyed brine is made to enter the decarbonization tank 2 for decarbonization, and hydrochloric acid is added to the decarbonization tank 2 to adjust the pH value of the dyed brine to 3.5, and air is blown in for continuous aeration, and the aeration time is 2h. After that, it enters the electrochemical reactor 3 as an electrolyte for decolorization, the electrolytic cell is a diaphragmless electrolytic cell, the anode is a ruthenium iridium electrode, the cathode is a graphite electrode, the electrolysis voltage of the control electrochemical reactor 3 is 6V, the current is 100A, the operating temperature is 40°C, the processing time is 2h, and the decolorized dyed brine is obtained, the chromaticity is 64 times, and the residual chlorine content is 215mg / L. After that, it enters the dechlorination tank 4 for dechlorination, and air is blown in for continuous aeration. The aeration time is 2 hours to obtain dechlorinated dyed brine, and the remaining chlorine content is 2.1 mg / L. The tail gas generated in the dechlorination process enters the tail gas absorption tower 5, and the dyed brine in the regulating tank 1 is used as the absorption liquid. The absorption liquid is contacted with the tail gas in countercurrent by spraying to absorb the chlorine therein to obtain the purified tail gas, and the absorption liquid after absorbing the chlorine in the tail gas is circulated to the regulating tank 1. The chlorine content in the purified tail gas is 0.2 mg / m 3, achieving safe and pollution-free discharge of the purified tail gas. Then the dechlorinated dyeing brine enters the neutralization tank 6, and sodium hydroxide is added to the neutralization tank 6 to adjust the pH value of the dyeing brine to 6.8 to obtain the treated dyeing brine. After that, the treated dyeing brine enters the reuse tank 7. The sodium chloride concentration of the treated dyeing brine is 82g / L, the pH value is 6.8, the chromaticity is 64 times, the residual chlorine content is 2.1mg / L, and the COD is 800mg / L.

[0071] The treated dyeing salt water is reused for dyeing, and the dyed fabric is 20-count double pure cotton semi-bleached cloth. A dyeing composition is added to the treated dyeing salt water, and the dyeing composition includes: active dark blue dye and substitute alkali, the amount of active dark blue dye added to the fabric is 6wt%, and the amount of substitute alkali added to the treated dyeing salt water is 4g / L, and no sodium chloride is added. The above fabric is dyed at 60°C for 60 minutes at a bath ratio of 1:10.

[0072] The dyed fabric of this embodiment is compared with the fabric dyed with fresh sodium chloride, and the color difference (△E) is 0.2, which proves that the recycled dyeing salt water of this embodiment has a better dyeing effect, and its dyeing effect and uniform dyeing are both better. Among them, the process of dyeing with fresh sodium chloride includes: preparing a sodium chloride aqueous solution, wherein the sodium chloride concentration is 82g / L, and the pH value is 6.5, adding a dyeing composition thereto, and the dyeing composition includes: a dye active navy blue and a substitute alkali, the amount of the dye active navy blue relative to the fabric is 6wt%, and the amount of the substitute alkali in the sodium chloride aqueous solution is 4g / L; dyeing the above fabric for 60min at a bath ratio of 1:10 at 60℃.

[0073] Comparative Example 1

[0074] This comparative example provides a system for recycling dyed brine, which is Figure 1 The dyed brine reuse system shown in FIG. 1 is basically the same, except that: the decarbonation tank 2 is not provided, the dyed brine outlet of the regulating tank 1 is connected to the dyed brine inlet of the electrochemical reactor 3, and the rest of the structure is the same as that of FIG. Figure 1 same.

[0075] In this comparative example, the pH value of the dyeing salt water in the regulating tank 1 is 11.1, the COD is 4500mg / L, the sodium chloride concentration is 100g / L, the chromaticity is 10000 times, and the total alkalinity is 2500mg / L. The dyeing salt water is made to enter the electrochemical reactor 3 as an electrolyte for decolorization, the electrolytic cell is a diaphragmless electrolytic cell, the anode is a ruthenium iridium electrode, the cathode is a graphite electrode, the electrolysis voltage of the control electrochemical reactor 3 is 6.3V, the current is 200A, the operating temperature is 60°C, the processing time is 1h, and the dyeing salt water after decolorization is obtained, and its chromaticity is 526 times, and the residual chlorine content is 432mg / L. Afterwards, hydrochloric acid is added into the dechlorination tank 4 to adjust the pH to 2.5 and dechlorinate, and air is blown in for continuous aeration, and the aeration time is 2h to obtain the dyeing salt water after dechlorination, and the remaining chlorine content is 5mg / L. The tail gas generated during the dechlorination process enters the tail gas absorption tower 5, and the dyed brine in the regulating tank 1 is used as the absorption liquid. The absorption liquid is sprayed in a countercurrent contact with the tail gas to absorb the chlorine therein to obtain the purified tail gas, and the absorption liquid after absorbing the chlorine in the tail gas is circulated to the regulating tank 1. The chlorine content in the purified tail gas is 0.3mg / m 3 Then the dechlorinated dyeing brine enters the neutralization tank 6, and sodium hydroxide is added to the neutralization tank 6 to adjust the pH value of the dyeing brine to 6.5 to obtain the treated dyeing brine. After that, the treated dyeing brine enters the reuse tank 7, and the sodium chloride concentration of the treated dyeing brine is 108g / L, the pH value is 6.5, the chromaticity is 512 times, the residual chlorine content is 5mg / L, and the COD is 2800mg / L.

[0076] The treated dyeing salt water is reused for dyeing, and the dyed fabric is 20-count double pure cotton semi-bleached cloth. A dyeing composition is added to the treated dyeing salt water, and the dyeing composition includes: dye ligenin black and substitute alkali, the amount of dye ligenin black added to the fabric is 7wt%, and the amount of substitute alkali added to the treated dyeing salt water is 4g / L, and no sodium chloride is added. The above fabric is dyed at 60°C for 60 minutes at a bath ratio of 1:10.

[0077] The dyed fabric of this comparative example was compared with the fabric dyed with fresh sodium chloride, and the color difference (ΔE) was 1.0. The dyeing process with fresh sodium chloride was the same as that in Example 1.

[0078] Comparative Example 2

[0079] This comparative example provides a system for recycling dyed brine, which is Figure 1 The dyeing brine recycling system shown in the figure is basically the same, except that: the dechlorination tank 4 and the tail gas absorption tower 5 are not provided, the regulating tank 1 is not provided with a dyeing brine circulation outlet and a dyeing brine circulation inlet, the dyeing brine outlet of the electrochemical reactor 3 is connected to the dyeing brine inlet of the neutralization tank 6, and the rest of the structure is the same as Figure 1 same.

[0080] In this comparative example, the pH value of the dyed brine in the regulating tank 1 is 11.1, the COD is 4500mg / L, the sodium chloride concentration is 100g / L, the chromaticity is 10000 times, and the total alkalinity is 2500mg / L. The dyed brine is made to enter the decarbonization tank 2 for decarbonization, and hydrochloric acid is added to the decarbonization tank 2 to adjust the pH value of the dyed brine to 2.5, and air is blown in for continuous aeration, and the aeration time is 1h. After that, it enters the electrochemical reactor 3 as an electrolyte for decolorization, the electrolytic cell is a diaphragmless electrolytic cell, the anode is a ruthenium iridium electrode, the cathode is a graphite electrode, the electrolysis voltage of the control electrochemical reactor 3 is 6V, the current is 200A, the operating temperature is 60°C, the processing time is 1h, and the decolorized dyed brine is obtained, the chromaticity is 128 times, and the residual chlorine content is 100mg / L. Then it enters the neutralization tank 6, and sodium hydroxide is added to the neutralization tank 6 to adjust the pH value of the dyed brine to 6.5 to obtain the treated dyed brine. The treated dyed brine then enters the reuse tank 7, and the treated dyed brine has a sodium chloride concentration of 108g / L, a pH value of 6.5, a chromaticity of 128 times, a residual chlorine content of 93mg / L, and a COD of 2100mg / L.

[0081] The treated dyeing salt water is reused for dyeing, and the dyed fabric is 20-count double pure cotton semi-bleached cloth. A dyeing composition is added to the treated dyeing salt water, and the dyeing composition includes: dye ligenin black and substitute alkali, the amount of dye ligenin black added to the fabric is 7wt%, and the amount of substitute alkali added to the treated dyeing salt water is 4g / L, and no sodium chloride is added. The above fabric is dyed at 60°C for 60 minutes at a bath ratio of 1:10.

[0082] The dyed fabric of this comparative example was compared with the fabric dyed with fresh sodium chloride, and the color difference (ΔE) was 2.1. The dyeing process with fresh sodium chloride was the same as that in Example 1.

[0083] It can be seen that, compared with the comparative examples, the dyed brine reuse system and method provided in the specific embodiments of the present invention achieve full reuse of the dyed brine and zero discharge of wastewater; and achieve the removal of residual chlorine in the tail gas and most of the dyes in the dyed brine, and the tail gas can be discharged safely; it has the advantages of low operating cost, simple operation, and no pollutants; and the obtained reusable treated dyed brine also has a good dyeing effect.

Claims

1. A system for recycling dyed brine, wherein: The dyed brine reuse system comprises: a regulating tank, a decarbonation tank, an electrochemical reactor, a dechlorination tank, a tail gas absorption tower and a neutralization tank; The regulating tank is at least provided with a dyed brine outlet, the decarbonization tank is at least provided with a dyed brine inlet, an acid inlet, a first aeration component and a dyed brine outlet, the electrochemical reactor is at least provided with a dyed brine inlet and a dyed brine outlet, the dechlorination tank is at least provided with a dyed brine inlet, a second aeration component, a tail gas outlet and a dyed brine outlet, the tail gas absorption tower is at least provided with a tail gas inlet, an absorption liquid inlet, an absorption liquid outlet and a purified tail gas outlet, and the neutralization tank is at least provided with a dyed brine inlet, an alkali inlet and a treated dyed brine outlet; The dyed brine outlet of the regulating tank is connected to the dyed brine inlet of the decarbonization tank; the dyed brine outlet of the decarbonization tank is connected to the dyed brine inlet of the electrochemical reactor; the dyed brine outlet of the electrochemical reactor is connected to the dyed brine inlet of the dechlorination tank; the tail gas outlet of the dechlorination tank is connected to the tail gas inlet of the tail gas absorption tower; the dyed brine outlet of the dechlorination tank is connected to the dyed brine inlet of the neutralization tank; the treated dyed brine outlet of the neutralization tank outputs the dyed brine for reuse.

2. The dyed brine reuse system according to claim 1, wherein: The regulating tank is also provided with a dyed brine circulation outlet and a dyed brine circulation inlet. The dyed brine circulation outlet is connected to the absorption liquid inlet of the tail gas absorption tower, and the absorption liquid outlet of the tail gas absorption tower is connected to the dyed brine circulation inlet, so as to use the dyed brine in the regulating tank as the absorption liquid to absorb the chlorine in the tail gas to obtain purified tail gas, and circulate the absorption liquid after absorbing the chlorine in the tail gas to the regulating tank.

3. The dyed brine reuse system according to claim 1, wherein: The acid inlet of the decarbonization tank is connected to an acid storage tank, and a first dosing pump is arranged on the pipeline connecting the acid inlet of the decarbonization tank and the acid storage tank.

4. The dyed brine reuse system according to claim 1, wherein: The first aeration component of the decarbonization tank at least includes an aeration pipe, and the aeration pipe is connected to an air source for blowing air into the decarbonization tank from the bottom of the decarbonization tank.

5. The dyed brine recycling system according to claim 1, wherein: The electrochemical reactor comprises at least an electrolytic cell, an anode and a cathode; Preferably, the electrolytic cell is a diaphragmless electrolytic cell; Preferably, the anode includes a metal oxide electrode, a glassy carbon electrode, a platinum electrode, a graphite electrode or a BDD electrode, and the cathode includes a pure metal electrode, a carbon material electrode or an alloy electrode.

6. The dyed brine recycling system according to claim 1, wherein: The second aeration assembly of the dechlorination tank at least comprises an aeration pipe, and the aeration pipe is connected to an air source for blowing air from the bottom of the dechlorination tank into the dechlorination tank.

7. The dyed brine recycling system according to claim 1, wherein: The tail gas inlet and the absorption liquid outlet of the tail gas absorption tower are arranged at the lower part of the tail gas absorption tower, and the absorption liquid inlet and the purified tail gas outlet of the tail gas absorption tower are arranged at the upper part of the tail gas absorption tower. A spray component is arranged in the tail gas absorption tower, and the spray component is connected with the absorption liquid inlet, and is used to use a spraying method to make the absorption liquid contact with the tail gas in countercurrent to absorb the chlorine therein to obtain the purified tail gas.

8. The dyed brine recycling system according to claim 1, wherein: The alkali inlet of the neutralization tank is connected to an alkali storage tank, and a second dosing pump is arranged on the pipeline connecting the alkali inlet of the neutralization tank and the alkali storage tank.

9. A method for recycling dyed brine, wherein: The method is carried out using the dyed brine reuse system according to any one of claims 1 to 8, and the method comprises the following steps: (1) Allowing dyed brine to enter the regulating tank to even out the water quality; (2) then entering the decarbonization tank for decarbonization, adding acid to the decarbonization tank to adjust the pH value of the dyed brine to 2.0-4.0, and blowing air into the decarbonization tank for continuous aeration, the aeration time is 0.5-4h; (3) then entering an electrochemical reactor as an electrolyte for decolorization, controlling the electrolysis voltage of the electrochemical reactor to be 2-100 V, the current to be 1-1000 A, the operating temperature to be 10-90° C., and the treatment time to be 0.1-10 h; (4) Then, the mixture is placed in a dechlorination tank for dechlorination, and air is blown in for continuous aeration for 2-8 hours to obtain tail gas and dechlorinated dyed brine; (5) the tail gas enters a tail gas absorption tower to absorb chlorine therein to obtain purified tail gas; (6) The dechlorinated dyeing brine enters a neutralization tank, into which alkali is added to adjust the pH value of the dechlorinated dyeing brine to neutral, thereby obtaining treated dyeing brine.

10. The method for recycling dyed brine according to claim 9, wherein: In step (5), the tail gas absorption tower uses the dyed brine in the regulating tank as the absorption liquid, and uses a spraying method to make the absorption liquid contact with the tail gas in countercurrent to absorb the chlorine therein, thereby obtaining the purified tail gas, and the absorption liquid after absorbing the chlorine in the tail gas is circulated to the regulating tank.

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