CN105683092B - For carrying out IPA concentration and the compound membrane separating method of wastewater treatment to the waste water containing IPA - Google Patents

Abstract

The present invention relates to a kind of compound membrane separating method for being used to carry out the waste water containing IPA IPA concentration and wastewater treatment, it is more particularly to combine osmotic evaporation film separation circuit and reverse osmosis membrane separation process, can be separated from the waste water containing IPA and concentrate IPA while the compound membrane separating method of processing waste water.According to the compound membrane separating method of the present invention, it can be cleaned from IPA in waste water and be optionally sequestered IPA, it is concentrated into more than 30 weight % to recycle, directly handled in existing waste water treatment plant without other dilutions further, it is possible to which the IPA of below 0.5 weight % low concentration is cleaned into waste water.

Description

Composite membrane separator for concentrating IPA and treating wastewater containing IPA off method

technical field

The present invention relates to the composite membrane separation method that is used to carry out the concentration of IPA and waste water treatment to the waste water that contains IPA, more specifically relates to the pervaporation membrane separation process and the reverse osmosis membrane separation process to combine, can be separated from the waste water that contains IPA and A composite membrane separation method that concentrates IPA and treats wastewater at the same time.

Background technique

IPA (isopropanol) is often used as a cleaning solution in industrial workshops, especially in semiconductor manufacturing processes and LCD manufacturing processes, and the cleaning wastewater after use usually contains 5% to 15% by weight of IPA. Regarding the wastewater generated in this way, from the viewpoint of recovery of organic compounds, especially alcohol, since the concentration of IPA is very low, it is not economical to separate and concentrate it using the usual distillation process. deal with the problem.

On the other hand, regarding such IPA cleaning wastewater, from the viewpoint of wastewater treatment, since the concentration of IPA is too high, there is another problem of diluting with water to reduce the concentration of IPA to 1% or less for wastewater treatment.

There have been previous studies (Patent Documents 1, 2) on pervaporation membrane separation processes for selectively separating water from alcohol/water mixed solutions such as IPA or organic solvents using pervaporation membranes. The technology of selectively separating organic compounds from an aqueous compound solution and using a reverse osmosis membrane separation process to treat wastewater is also known (Patent Documents 3 and 4), but the pervaporation membrane separation process and the reverse osmosis membrane separation process are used as carried out by different processes.

Therefore, for the IPA cleaning wastewater that is not suitable for concentration to recycle or carry out wastewater treatment concentration, if using the pervaporation membrane separation process to concentrate IPA, use the reverse osmosis membrane separation process to separate IPA together to make the IPA concentration If it becomes a concentration suitable for wastewater treatment, all the IPA cleaning wastewater that has been treated in the past can be selectively separated and concentrated for recycling, and the low-concentration IPA cleaning wastewater can be used without other dilution. Some waste water treatment plants directly treat the waste water, and the present inventors have completed the present invention focusing on the above-mentioned situation.

prior art literature

patent documents

Patent Document 1: Japanese Laid-Open Patent Publication No. 10-2011-0083077;

Patent Document 2: Japanese Laid-Open Patent Publication No. 10-2000-0067454;

Patent Document 3: Japanese Laid-Open Patent Publication No. 10-2013-0032294;

Patent Document 4: Japanese Laid-Open Patent Publication No. 10-2005-0026294.

Contents of the invention

The problem to be solved by the invention

The present invention is made in view of the above-mentioned problems, and its purpose is to provide a kind of composite membrane separation method that has combined pervaporation membrane separation process and reverse osmosis membrane separation process, can separate IPA selectively from IPA cleaning waste water and It is concentrated to more than 30% by weight for recovery and reuse, and low-concentration IPA cleaning wastewater below 0.5% by weight can be directly treated in existing wastewater treatment plants without other dilution.

solutions to problems

In order to achieve said object, the invention provides a kind of composite membrane separation method, comprising: 1) the step of concentrating IPA from the wastewater containing IPA by pervaporation membrane separation process; Wastewater Treatment of wastewater steps.

It is characterized in that, the pervaporation membrane separation process of the step I) includes: i) the step of supplying the heated wastewater containing IPA to the pervaporation membrane module; ii) condensing the IPA permeated through the pervaporation membrane module into the step of the liquid phase; and iii) the step of transferring the coagulated IPA to the permeate solution tank.

It is characterized in that the heated wastewater containing IPA is maintained at 30°C to 60°C by a heater.

It is characterized in that the supply flow rate of the wastewater containing IPA supplied to the pervaporation membrane module is more than 5 times of the permeate flow rate.

It is characterized in that, the reverse osmosis membrane separation process of said II) step includes: a) the step of supplying the boosted wastewater containing IPA to the reverse osmosis membrane module; Step to move to permeate tank.

It is characterized in that the boosted wastewater containing IPA is maintained at 10bar-70bar by a high-pressure pump.

It is characterized in that the supply flow rate of the wastewater containing IPA supplied to the reverse osmosis membrane module is more than three times the permeate flow rate.

Invention effect

According to the composite membrane separation method of the present invention, IPA can be selectively separated from the IPA cleaning wastewater, and it can be concentrated to more than 30% by weight for recycling, and at the same time, the low-concentration IPA cleaning wastewater below 0.5% by weight can not be used. Other dilutions are carried out for direct treatment in existing wastewater treatment plants.

Description of drawings

Fig. 1 is the block diagram showing continuous type (continuous) composite membrane separation method of the present invention;

Fig. 2 is a block diagram showing a batch composite membrane separation method of the present invention.

Detailed ways

Hereinafter, the composite membrane separation method of the present invention that uses the pervaporation membrane separation process to concentrate IPA and simultaneously uses the reverse osmosis membrane separation process to separate IPA so that the concentration of IPA is suitable for wastewater treatment and the accompanying drawings will be described in detail.

The invention provides a composite membrane separation method, comprising: I) a step of concentrating IPA from wastewater containing IPA through a pervaporation membrane separation process; and II) a step of treating wastewater from the wastewater containing IPA through a reverse osmosis membrane separation process.

In addition, the pervaporation membrane separation process of the above-mentioned I) step includes: i) the step of supplying the heated wastewater containing IPA to the pervaporation membrane module; ii) condensing the IPA permeated through the pervaporation membrane module into liquid phase and iii) the step of transferring the coagulated IPA to the permeation solution tank, as shown in the continuous (continuous) process block diagram of Figure 1, at first, the waste water (IPA solution) containing IPA is stored in the IPA solution tank 100, using Common heating means such as the heater 110 raises the temperature of the IPA solution in the IPA solution tank. At this time, if the temperature of the IPA solution is less than 30°C, the permeation amount of the pervaporation membrane module is too small, and if the temperature of the IPA solution exceeds 60°C, the energy consumption is too large. Therefore, it is preferable that the IPA solution is heated by the heater 110 to maintain Between 30°C and 60°C.

Next, the IPA solution heated to 30° C. to 60° C. is supplied to the pervaporation membrane module 150 , where it passes through the IPA solution supply pump 120 , the solution filter 130 and the IPA solution flow meter 140 in sequence. At this time, it is preferable to adjust the supply flow rate of the IPA solution supplied to the pervaporation membrane module 150 to 5 times or more of the permeation flow rate. If the IPA solution is supplied to the pervaporation membrane module 150 at 5 times or less the permeate flow rate, the permeate solution that permeates through the pervaporation membrane module 150 will have a low IPA concentration, and thus cannot be separated and concentrated smoothly.

The IPA solution supplied to the pervaporation membrane module 150 in this way has an action mechanism in which IPA dissolves in the separation membrane, diffuses in the separation membrane, and permeates in the gas phase. According to this mechanism of action, one end of the pervaporation membrane module 150 is in contact with the IPA feed solution, and the other end is in contact with the low vapor pressure of the permeate, which can be generated by evacuating or flowing an inert carrier gas. Therefore, generally, a gradient of chemical potential energy as a driving force (driving force) of the pervaporation membrane separation process is generated inside the pervaporation membrane, and the permeation of the substance through the membrane is performed. Therefore, in the present invention, in order to maintain the pervaporation membrane separation The driving force of the process is to maintain a vacuum in the permeation part by using the vacuum pump 170 .

Next, the gas-phase IPA permeated through the pervaporation membrane module 150 is condensed into a liquid phase in a normal condenser 160 , and the condensed liquid-phase IPA is transferred to the permeate solution tank 190 through the permeate solution flow meter 180 . The IPA solution obtained by this pervaporation membrane separation process is concentrated to 30% or more, so it can be recovered and reused.

On the other hand, in the composite membrane separation method of the present invention, the reverse osmosis membrane separation process is carried out simultaneously, and the reverse osmosis membrane separation process of the above-mentioned II) step comprises: a) the waste water containing IPA after boosting is supplied to the reverse osmosis membrane module and b) the step of transferring the waste water that has penetrated the reverse osmosis membrane module to the permeation water tank, as shown in the continuous process block diagram of Figure 1, at first, the waste water containing IPA is passed through the solution filter 210 from the IPA solution tank 100 Transfer to the IPA solution high-pressure pump 220 to boost the pressure of the IPA solution. At this time, the supply pressure of the high-pressure pump 220 is preferably maintained at 10bar to 70bar. If it is operated at less than 10bar, the propulsive force will be low, so the permeation of the reverse osmosis membrane will be greatly reduced. If it exceeds 70bar, the long-term stability of the reverse osmosis membrane will be reduced. Therefore, it is adjusted so that the pressure of the IPA solution is boosted by the high-pressure pump 220 and maintained at 10 bar to 70 bar.

Next, the IPA solution boosted to 10bar to 70bar is supplied to the reverse osmosis membrane module 240 through the solution flowmeter 230 , and the wastewater permeated through the reverse osmosis membrane module 240 is transferred to the permeate water tank 260 through the permeate water flowmeter 250 . Wastewater (permeated water) permeated through this reverse osmosis membrane separation process has a concentration of IPA of 0.5% or less, so it may be treated in a waste water treatment plant without further dilution.

As explained above, in the actual continuous (continuous) composite membrane separation method shown in FIG. 1, a fixed amount of wastewater containing IPA (IPA solution) is filled into the tank 100, and the IPA is separated and concentrated using the pervaporation membrane separation process. At the same time, the reverse osmosis membrane separation process is also performed to permeate water (waste water) and transfer it to the permeate water tank 260 . Now, confirm the amount of the IPA concentrated solution of the pervaporation membrane separation process and the amount of permeate water in the reverse osmosis membrane separation process, the IPA solution tank 100 is continuously replenished, according to the amount to be continuously processed (continuous waste water production amount) ) to design the capacity of the pervaporation membrane separation process and the reverse osmosis membrane separation process, and these processes can be operated continuously.

On the other hand, as another operation example, it is also possible to carry out the composite membrane separation method of batch (batch) formula shown in FIG. After the membrane separation process separates and concentrates IPA, when the concentration of the original waste water containing IPA drops below a certain concentration, the solution in the IPA solution tank 100 is transferred to another IPA solution tank 200, and the transferred waste water containing IPA Through the reverse osmosis membrane separation process, water is infiltrated and stored in the permeation water tank 260. Water is removed from the IPA solution in the IPA solution tank 200. When the IPA increases to a certain concentration, it is transferred to the IPA solution tank 100, and the pervaporation membrane separation process is performed again. By repeating the above steps, all the waste water containing IPA is treated, and the permeate water in the permeate water tank 260 can be treated in a waste water treatment plant because the concentration of IPA is reduced.

In addition, although not shown in the accompanying drawings, the following semi-batch (semi-batch) composite membrane separation method can also be carried out: the tank 100 is filled with a fixed amount of wastewater containing IPA (IPA solution), While the evaporation membrane separation process separates and concentrates IPA, it also performs the reverse osmosis membrane separation process together to infiltrate water (waste water) and transfer it to the permeation water tank 260, and then continue to run. When the level of the IPA solution tank 100 is When it becomes below a certain amount, waste water containing IPA is replenished, and it operates in batch mode according to the upper limit and lower limit levels of the IPA solution tank 100 .

On the other hand, as the membrane material of the pervaporation membrane separation process included in the composite membrane separation method of the present invention, it is preferable to coat polydimethylsiloxane (PDMS) on a porous support such as polyetherimide. Silicone-based composite films of organopolysiloxanes, but not limited thereto. In addition, as the membrane material in the reverse osmosis membrane separation step, a polyamide-based composite membrane in which polyamide is coated on a porous support such as polysulfone is preferable, but not limited thereto.

Detailed ways

Hereinafter, specific examples will be described in detail.

(Example 1)

The IPA concentration of the wastewater containing IPA is fixed at 5.2% by weight, the supply flow rate is fixed at 80LPM (liter per minute, liters per minute), the temperature of the supply solution is changed to 35°C, 45°C and 55°C respectively, and the process shown in Figure 1 is carried out. For the continuous composite membrane separation method shown, Table 1 shows the IPA concentration and permeation flow rate of the permeate solution according to the temperature of the solution supplied in the pervaporation membrane separation process.

[Table 1]

(Example 2)

Except that the concentration of IPA in the wastewater containing IPA was fixed at 8.7% by weight, the continuous composite membrane separation method was carried out in the same manner as in Example 1, and Table 2 shows the permeate solution according to the temperature of the supply solution in the pervaporation membrane separation process. The concentration of IPA and permeate flow rate.

[Table 2]

(Example 3)

The temperature of the supply solution is fixed at 35°C, the supply flow rate is fixed at 20LPM, and the concentration of IPA in the wastewater containing IPA is changed to 5.2% by weight, 6.2% by weight, 7.3% by weight and 8.5% by weight respectively, and the process shown in Figure 1 is carried out. The continuous composite membrane separation method, table 3 shows the concentration and permeate flow of the IPA of the permeate solution (permeate water) of the reverse osmosis membrane separation process.

[table 3]

As shown in table 1 and table 2, according to the pervaporation membrane separation process of embodiment 1 and 2 of the composite membrane separation method of the present invention, it can be known that under the same situation of the temperature of the supply solution, the concentration of IPA in the wastewater containing IPA is higher. The higher the concentration of IPA in the permeate solution and the higher the permeate flow rate, it was confirmed that the concentration of IPA in the permeate solution was 38% or more in all cases, and the permeate solution could be recovered and reused.

And, as shown in table 3, according to the reverse osmosis membrane separation process of the embodiment 3 of the composite membrane separation method of the present invention, when the concentration of the IPA (concentration of the supply solution) of the waste water containing IPA increases from 5.2% by weight to 8.5% by weight %, the concentration of IPA in the permeate solution (permeate water) slightly increased, and the permeate flow rate decreased, but in all cases, the concentration of IPA in the permeate solution (permeate water) was less than 0.5% by weight. Therefore, it was confirmed that the permeate solution (permeate water) could (permeate water) is directly transferred to the wastewater treatment plant for wastewater treatment.

Industrial availability

Therefore, according to the composite membrane separation method of the present invention, the following remarkable effects are shown, that is, IPA can be selectively separated from IPA cleaning wastewater, and it is concentrated to more than 30% by weight for recycling, and, 0.5% by weight or less The low-concentration IPA cleaning wastewater can be directly treated in the existing wastewater treatment plant without other dilution.

Claims (3)

1. a kind of compound membrane separating method, including：

I the step of isopropanol (IPA)) is concentrated from the waste water containing isopropanol (IPA) by osmotic evaporation film separation circuit；With And

II) by reverse osmosis membrane separation process from the wastewater treatment waste water containing isopropanol (IPA) the step of,

Wherein, the I) the osmotic evaporation film separation circuit of step includes：

I) the step of waste water containing isopropanol (IPA) that will heat up is supplied to pervaporation film module；

Ii the step of isopropanol (IPA) for having penetrated pervaporation film module) is condensed into liquid phase；And

Iii the step of curdy isopropanol (IPA)) is transplanted on percolating solution case,

The II) the reverse osmosis membrane separation process of step includes：

A) waste water containing isopropanol (IPA) by the boosting that 10bar~70bar is maintained by high-pressure pump is supplied to counter-infiltration The step of film module；And

B) the step of move wastewater of reverse osmosis membrane module is to infiltration water tank will have been penetrated,

Wherein, the supply flow rate for being supplied to the waste water containing isopropanol (IPA) of the pervaporation film module is seepage discharge More than 5 times, and

Wherein, the membrane material in the osmotic evaporation film separation circuit is poly- to be coated with the porous supporting mass of PEI The silicone composite membrane of dimethyl siloxane, and the membrane material in the reverse osmosis membrane separation process is the porous in polysulfones Supporting mass is coated with the polyamide-based composite membrane of polyamide.

2. compound membrane separating method as claimed in claim 1, it is characterised in that

The waste water containing isopropanol (IPA) to have heated up maintains 30 DEG C~60 DEG C by heater.

3. compound membrane separating method as claimed in claim 1, it is characterised in that

Be supplied to the supply flow rate of the waste water containing isopropanol (IPA) of the reverse osmosis membrane module for 3 times of seepage discharge with On.