CN115710031A - Method for treating photoresist developer wastewater containing 1,4-dioxane - Google Patents

Abstract

The invention discloses a method for treating photoresist developer wastewater containing 1,4-dioxane, wherein the wastewater is distilled from a rectifying tower under normal pressure, the distillate at the top of the tower is high-concentration 1,4-dioxane-containing aqueous solution, part of the aqueous solution is fed into a high-pressure rectifying tower, the liquid discharged from the bottom of the tower is high-purity water, part of the distillate at the top of the high-pressure rectifying tower is circularly returned to the normal-pressure rectifying tower, and the liquid discharged from the bottom of the tower is high-concentration 1,4-dioxane. The invention has the advantages that: after the photoresist developer wastewater containing 1,4-dioxane is treated, the high-purity 1,4-dioxane can be obtained, can be directly recycled after subsequent resin adsorption, can discharge high-purity water, and the purified wastewater meets the industrial environment-friendly requirement, can be directly discharged, and realizes win-win of economic benefit and environmental-friendly benefit; the wastewater treatment has the characteristics of large scale and continuity, the wastewater treatment capacity is large, a third component is not required to be introduced, secondary pollutants are not generated, and a large amount of energy can be saved.

Description

Method for treating photoresist developer wastewater containing 1,4-dioxane

technical field

The invention relates to a wastewater treatment method, in particular to a photoresist developer wastewater treatment method containing 1,4-dioxane.

Background technique

Electronic grade 1,4-Dioxane (1,4-Dioxane) is an important raw material for producing photoresist developer. At present, there is no domestic manufacturer that mass-produces this raw material, and the related production technology is monopolized by multinational companies such as Japan and South Korea. The domestic chip industry can only buy from foreign countries at high prices. On the other hand, 1,4-dioxane is carcinogenic and cannot be emitted directly. Therefore, in terms of raw material utilization and environmental protection, the recovery of 1,4-dioxane from photoresist developer wastewater containing 1,4-dioxane has great economic and environmental significance.

The treatment of photoresist developer wastewater containing 1,4-dioxane requires comprehensive consideration of 1,4-dioxane recovery and water purification. At present, the traditional treatment method of wastewater containing 1,4-dioxane uses cyclohexane as the entrainer, and adopts the azeotropic distillation method to pre-concentrate, add entrainer, regenerate the entrainer, and purify five towers. High-purity 1,4-dioxane is recovered through the rectification process. The process is long, resulting in high energy consumption; the use of entrainer, the system introduces additional chemical substances, which not only increases the treatment cost but also increases the complexity of the treatment process, resulting in secondary pollution in terms of environmental protection.

Contents of the invention

Purpose of the invention: The purpose of the invention is to provide a treatment method for photoresist developer wastewater containing 1,4-dioxane, which can not only obtain high-purity 1,4-dioxane, but also discharge high-purity water .

Technical solution: a method for treating photoresist developer wastewater containing 1,4-dioxane, comprising the following steps:

Step 100, the waste water is sent to the atmospheric rectification tower, the overhead distillate of the atmospheric rectification tower is a high-concentration aqueous solution containing 1,4-dioxane, and the discharge liquid from the tower kettle is high-purity water; the high-concentration 1,4-dioxane , Part of the 4-dioxane aqueous solution is refluxed into the atmospheric rectification tower, and the rest is sent into the high-pressure rectification tower;

In step 200, part of the overhead distillate of the high-pressure rectification tower is refluxed into the high-pressure rectification tower, and the rest is circulated back to the atmospheric rectification tower, and the liquid discharged from the bottom of the tower is high-concentration 1,4-dioxane.

Specifically, the composition of the waste water is 2-5% of 1,4-dioxane and 95-98% of water, in mass percent.

Furthermore, the operating conditions of the atmospheric distillation tower are: normal pressure, the temperature of the bottom of the tower is 100-105°C, the number of theoretical plates is 20-50, and the reflux ratio is 0.5-5.

Furthermore, the operating conditions of the high-pressure rectification tower are: 800-1000kpa, the temperature of the tower bottom is 165-205°C, the number of theoretical plates is 16-30, and the reflux ratio is 1-3.

Specifically, in step 100, the composition of the high-concentration 1,4-dioxane-containing aqueous solution is 75-81% of 1,4-dioxane and 19-25% of water, in mass percent; high-purity The mass purity of water is higher than 99.99%.

Specifically, in step 200, the composition of the overhead distillate is 65-74% of 1,4-dioxane and 26-30% of water, in mass percentage; high concentration 1,4-dioxane The mass purity of the ring is 99.99-99.998%.

The principle of the present invention is: according to the sensitivity of 1,4-dioxane and water binary systems to pressure, pressure swing rectification is adopted, and the characteristic that the composition ratio of azeotrope changes significantly with pressure changes is used, and the low The photoresist developer wastewater containing 1,4-dioxane in high concentration is separated by pressure swing rectification, so as to realize recovery and extraction of electronic grade 1,4-dioxane therefrom.

Beneficial effect: the advantage of the present invention is that after the photoresist developer wastewater containing 1,4-dioxane is treated, high-purity 1,4-dioxane can be obtained, which is absorbed by the subsequent resin It can be directly recycled, and can also discharge high-purity water. The purified wastewater meets the environmental protection requirements of the industry and can be discharged directly to achieve a win-win situation of economic and environmental benefits. The third component needs to be introduced, no secondary pollutants will be generated, and a large amount of energy can be saved at the same time.

Description of drawings

Fig. 1 is a flow chart of the method of the present invention.

Detailed ways

The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments.

Example 1

A method for treating photoresist developer wastewater containing 1,4-dioxane, specifically comprising the following steps:

Step 100: Send the waste water into the atmospheric rectification tower at a flow rate of 1000 kg/h. The mass percentage of 1,4-dioxane in the waste water is 2%, and the rest is water.

Atmospheric rectification is carried out in the atmospheric rectification tower, and the operating conditions of the atmospheric rectification tower are normal pressure, 102° C. in the bottom of the tower, 20 theoretical plates, and 3 reflux ratios.

The distillate at the top of the tower is a high-concentration 1,4-dioxane-containing aqueous solution. After being condensed by the condenser, part of it is refluxed and sent to the atmospheric rectification tower, and the rest is sent to the high-pressure rectification tower at a flow rate of 113kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 76%, and the rest is water. The liquid discharged from the tower kettle is high-purity water, which flows out of the atmospheric distillation tower at a flow rate of 980kg/h, and the mass percentage of 1,4-dioxane in the high-purity water is less than 0.0001%.

Step 200: Carry out high-pressure rectification in a high-pressure rectification tower. The operating conditions of the high-pressure rectification tower are 800 kPa, the temperature of the tower bottom is 188° C., the number of theoretical plates is 16, and the reflux ratio is 1.

After the overhead distillate is condensed by the condenser, part of the reflux is sent to the high-pressure rectification tower, and the rest is circulated back to the atmospheric rectification tower at a flow rate of 93kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 70%, and the rest is water. The liquid discharged from the tower kettle is 1,4-dioxane with a mass purity of 99.996% and high concentration, and flows out of the high-pressure rectification tower at a flow rate of 20 kg/h.

Example 2

A method for treating photoresist developer wastewater containing 1,4-dioxane, specifically comprising the following steps:

Step 100: Send the waste water into the atmospheric rectification tower at a flow rate of 1000 kg/h. The mass percentage of 1,4-dioxane in the waste water is 5%, and the rest is water.

Atmospheric rectification is carried out in the atmospheric rectification tower. The operating conditions of the atmospheric rectification tower are atmospheric pressure, tower bottom temperature 102°C, theoretical plate number 20, and reflux ratio 0.7.

The distillate at the top of the tower is a high-concentration 1,4-dioxane-containing aqueous solution. After being condensed by the condenser, part of it is refluxed and sent to the atmospheric rectification tower, and the rest is sent to the high-pressure rectification tower at a flow rate of 143kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 80%, and the rest is water. The liquid discharged from the tower kettle is high-purity water, which flows out of the atmospheric distillation tower at a flow rate of 950kg/h, and the mass percentage of 1,4-dioxane in the high-purity water is less than 0.0001%.

Step 200: Carry out high-pressure rectification in a high-pressure rectification tower. The operating conditions of the high-pressure rectification tower are 800 kPa, 166° C. tower bottom temperature, 16 theoretical plates, and 1 reflux ratio.

After the overhead distillate is condensed by the condenser, part of the reflux is sent to the high-pressure rectification tower, and the rest is circulated back to the atmospheric rectification tower at a flow rate of 93kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 72%, and the rest is water. The liquid discharged from the bottom of the tower is high-concentration 1,4-dioxane with a mass purity of 99.995%, and flows out of the high-pressure rectification tower at a flow rate of 50 kg/h.

Example 3

A method for treating photoresist developer wastewater containing 1,4-dioxane, specifically comprising the following steps:

Step 100: Send the waste water into the atmospheric rectification tower at a flow rate of 1000 kg/h. The mass percentage of 1,4-dioxane in the waste water is 5%, and the rest is water.

Atmospheric rectification is carried out in the atmospheric rectification tower. The operating conditions of the atmospheric rectification tower are atmospheric pressure, tower bottom temperature 102°C, theoretical plate number 20, and reflux ratio 0.7.

The distillate at the top of the tower is a high-concentration 1,4-dioxane-containing aqueous solution. After being condensed by the condenser, part of it is refluxed and sent to the atmospheric rectification tower, and the rest is sent to the high-pressure rectification tower at a flow rate of 143kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 80%, and the rest is water. The liquid discharged from the tower kettle is high-purity water, which flows out of the atmospheric distillation tower at a flow rate of 950kg/h, and the mass percentage of 1,4-dioxane in the high-purity water is less than 0.0001%.

Step 200: Carry out high-pressure rectification in the high-pressure rectification tower. The operating conditions of the high-pressure rectification tower are 1000 kPa, the temperature of the bottom of the tower is 200° C., the number of theoretical plates is 16, and the reflux ratio is 1.

After the overhead distillate is condensed by the condenser, part of the reflux is sent to the high-pressure rectification tower, and the rest is circulated back to the atmospheric rectification tower at a flow rate of 93kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 69%, and the rest is water. The liquid discharged from the bottom of the tower is high-concentration 1,4-dioxane with a mass purity of 99.995%, and flows out of the high-pressure rectification tower at a flow rate of 50 kg/h.

Example 4

A method for treating photoresist developer wastewater containing 1,4-dioxane, specifically comprising the following steps:

Step 100: Send the waste water into the atmospheric rectification tower at a flow rate of 1000 kg/h. The mass percentage of 1,4-dioxane in the waste water is 5%, and the rest is water.

Atmospheric rectification is carried out in the atmospheric rectification tower, and the operating conditions of the atmospheric rectification tower are atmospheric pressure, tower bottom temperature 102°C, theoretical plate number 20, and reflux ratio 1.4.

The distillate at the top of the tower is a high-concentration 1,4-dioxane-containing aqueous solution. After being condensed by the condenser, part of it is refluxed and sent to the atmospheric rectification tower, and the rest is sent to the high-pressure rectification tower at a flow rate of 143kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 80%, and the rest is water. The liquid discharged from the tower kettle is high-purity water, which flows out of the atmospheric distillation tower at a flow rate of 950kg/h, and the mass percentage of 1,4-dioxane in the high-purity water is less than 0.0007%.

Step 200: Carry out high-pressure rectification in the high-pressure rectification tower. The operating conditions of the high-pressure rectification tower are 1000 kPa, the temperature of the bottom of the tower is 200° C., the number of theoretical plates is 16, and the reflux ratio is 3.

After the overhead distillate is condensed by the condenser, part of the reflux is sent to the high-pressure rectification tower, and the rest is circulated back to the atmospheric rectification tower at a flow rate of 93kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 69%, and the rest is water. The liquid discharged from the tower kettle is 1,4-dioxane with a mass purity of 99.997% and high concentration, and flows out of the high-pressure rectification tower at a flow rate of 50 kg/h.

Example 5

A method for treating photoresist developer wastewater containing 1,4-dioxane, specifically comprising the following steps:

Step 100: Send the waste water into the atmospheric rectification tower at a flow rate of 1000 kg/h. The mass percentage of 1,4-dioxane in the waste water is 5%, and the rest is water.

Atmospheric rectification is carried out in the atmospheric rectification tower, and the operating conditions of the atmospheric rectification tower are normal pressure, tower bottom temperature 102°C, 30 theoretical plates, and reflux ratio 0.7.

The distillate at the top of the tower is a high-concentration 1,4-dioxane-containing aqueous solution. After being condensed by the condenser, part of it is refluxed and sent to the atmospheric rectification tower, and the rest is sent to the high-pressure rectification tower at a flow rate of 143kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 80%, and the rest is water. The liquid discharged from the tower kettle is high-purity water, which flows out of the atmospheric rectification tower at a flow rate of 950kg/h, and the mass percentage of 1,4-dioxane in the high-purity water is less than 0.00008%.

Step 200: Carry out high-pressure rectification in the high-pressure rectification tower. The operating conditions of the high-pressure rectification tower are 1000 kPa, the temperature of the tower bottom is 200° C., the number of theoretical plates is 24, and the reflux ratio is 1.

After the overhead distillate is condensed by the condenser, part of the reflux is sent to the high-pressure rectification tower, and the rest is circulated back to the atmospheric rectification tower at a flow rate of 93kg/h. The mass percent content of 1,4-dioxane in the overhead distillate is 69%, and the rest is water. The liquid discharged from the bottom of the tower is high-concentration 1,4-dioxane with a mass purity of 99.998%, and flows out of the high-pressure rectification tower at a flow rate of 50 kg/h.

Accompanying drawing 1 shows that the present invention carries out the flow chart of wastewater treatment.

In photoresist developer wastewater containing 1,4-dioxane, 1,4-dioxane and water form an azeotrope with a water content of 19.4% under normal pressure, and the azeotropic temperature is 87.74°C. According to the sensitivity of 1,4-dioxane and water binary system to pressure, the waste water treatment method of the present invention adopts pressure swing rectification, and utilizes the characteristic that the composition ratio of azeotrope changes significantly with the change of pressure. The low-concentration photoresist developer wastewater containing 1,4-dioxane is separated by pressure swing rectification to realize the recovery and extraction of electronic grade 1,4-dioxane, which can obtain high-purity 1,4-dioxane Dioxane, after subsequent resin adsorption, can be directly recycled, and high-purity water can be discharged. The purified wastewater meets the environmental protection requirements of the industry and can be discharged directly, achieving a win-win situation of economic and environmental benefits.

The wastewater treatment method has the characteristics of large-scale and continuous operation, a large amount of wastewater treatment, no need to introduce a third component, no secondary pollutants, and can save a lot of energy at the same time.

Claims (6)

1. A method for treating photoresist developer wastewater containing 1,4-dioxane is characterized by comprising the following steps:

step 100, feeding the wastewater into an atmospheric distillation tower, wherein the distillate at the top of the atmospheric distillation tower is a high-concentration 1,4-dioxane-containing aqueous solution, and the liquid discharged from the tower bottom is high-purity water; part of the high-concentration 1,4-dioxane-containing aqueous solution is refluxed and sent to the atmospheric distillation tower, and the rest is sent to the high-pressure distillation tower;

200, refluxing part of the tower top distillate of the high-pressure rectifying tower to be sent into the high-pressure rectifying tower, and circularly returning the rest to the normal-pressure rectifying tower, wherein the tower bottom discharge liquid is high-concentration 1,4-dioxane.

2. The method of claim 1 wherein the photoresist developer wastewater treatment process comprises 1,4-dioxane, wherein the method comprises: the composition of the waste water is 2-5% of 1,4-dioxane and 95-98% of water by mass percentage.

3. The method of claim 1 wherein the photoresist developer wastewater treatment process comprises 1,4-dioxane, wherein the method comprises: the operating conditions of the atmospheric distillation column are as follows: normal pressure, tower temperature 100-105 deg.c, theoretical plate number 20-50, reflux ratio 0.5-5.

4. The method of claim 1 wherein the method comprises treating the photoresist developer wastewater containing 1,4-dioxane: operating conditions of the high-pressure rectification column: 800-1000 kpa, the temperature of the tower kettle is 165-205 ℃, the number of theoretical plates is 16-30, and the reflux ratio is 1-3.

5. The method of claim 1 wherein the photoresist developer wastewater treatment process comprises 1,4-dioxane, wherein the method comprises: in the step 100, the high-concentration 1,4-dioxane aqueous solution comprises 75-81% of 1,4-dioxane and 19-25% of water by mass percentage; the high-purity water has a mass purity of greater than 99.99%.

6. The method of claim 1 wherein the photoresist developer wastewater treatment process comprises 1,4-dioxane, wherein the method comprises: in the step 200, the composition of the distillate at the top of the tower is 65-74 percent of 1,4-dioxane and 26-30 percent of water by mass percentage; the mass purity of the high-concentration 1,4-dioxane is 99.99-99.998%.

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