WO2015053483A1

WO2015053483A1 - Combined membrane separation process for concentrating ipa from wastewater containing ipa and treating wastewater

Info

Publication number: WO2015053483A1
Application number: PCT/KR2014/008334
Authority: WO
Inventors: 하성용; 고형철; 이충섭; 배은석; 임채성
Original assignee: (주)에어레인; 주식회사 에너엔비텍
Priority date: 2013-10-07
Filing date: 2014-09-04
Publication date: 2015-04-16
Also published as: CN105683092B; CN105683092A; JP6235133B2; KR20150040455A; KR101695215B1; JP2016532542A

Abstract

The present invention relates to a combined membrane separation process for concentrating IPA from wastewater containing IPA and treating wastewater, and more specifically, to a combined membrane separation process capable of separating and concentrating IPA from wastewater containing IPA and simultaneously treating wastewater by combining a pervaporation membrane separation process and a reverse osmosis membrane separation process. According to the combined membrane separation process of the present invention, IPA can be selectively separated from IPA washing wastewater and concentrated to 30 wt% or more, thereby recycling the same, and simultaneously, IPA washing wastewater having a low concentration of 0.5 wt% or less can be treated, as is, in a conventional wastewater treatment plant without separate dilution.

Description

Combined Membrane Separation Process for Concentration and Wastewater Treatment of IPA from IPA-Containing Wastewater

The present invention relates to a combined membrane separation process for concentrating IPA and wastewater treatment from IPA-containing wastewater, and more specifically, combining and separating permeation membrane separation and reverse osmosis membrane separation to separate and concentrate IPA from IPA-containing wastewater. The present invention relates to a combined membrane separation process capable of treating wastewater at the same time.

IPA (isopropyl alcohol) is widely used as a cleaning solution in industrial sites, especially in semiconductor manufacturing processes and LCD manufacturing processes, and the used wastewater generally contains 5 to 15% by weight of IPA. The wastewater generated in this way has a problem in that the total amount of the wastewater is currently treated because the concentration of IPA is very low, so that the concentration of IPA is very low, so it is not economical at the time of separation and concentration using a conventional distillation process.

On the other hand, such an IPA cleaning wastewater in terms of wastewater treatment, there is another problem that the IPA concentration is too high to dilute with water to lower the IPA concentration to less than 1% to treat the wastewater.

There have been prior studies on permeation membrane separation process for selectively separating water from a mixture of alcohol / water such as IPA using pervaporation membrane or selectively separating organic compounds from an aqueous solution of organic compounds (Patent Documents 1 and 2). Although the technology for treating wastewater using the reverse osmosis membrane separation process is widely known (Patent Documents 3 and 4), the permeation membrane separation process and the reverse osmosis membrane separation process were performed in separate processes according to their respective uses and characteristics.

Therefore, the present inventors concentrate IPA from permeate membrane separation process of IPA cleaning wastewater of concentration which is not suitable for concentration and recycling or wastewater treatment, and at the same time, it is possible to adjust IPA concentration to wastewater treatment using reverse osmosis membrane separation process. By combining the concentration separation process, IPA can be selectively separated, concentrated, and recycled from the IPA cleaning wastewater, which has been treated in the whole wastewater, and the low concentration of IPA cleaning wastewater can be recycled in the existing wastewater treatment plant without dilution. The present invention has been accomplished by focusing on the process.

Patent Document 1 Publication No. 10-2011-0083077

Patent Document 2 Publication No. 10-2000-0067454

Patent Document 3 Publication No. 10-2013-0032294

Patent Document 4 Publication No. 10-2005-0026294

The present invention has been made in view of the above problems, and an object of the present invention is to selectively recycle and recycle IPA from IPA washing waste water by concentrating 30% by weight or more, and at the same time, a low concentration of IPA of 0.5% by weight or less. Washing waste water is to provide a combined membrane separation process combined with a permeation membrane separation process and a reverse osmosis membrane separation process that can be treated as it is in the existing wastewater treatment plant without separate dilution.

The present invention for achieving the object as described above I) concentrating the IPA through the permeation membrane separation process from the IPA-containing waste water; And II) treating the wastewater from the IPA-containing wastewater through a reverse osmosis membrane separation process.

The pervaporation membrane separation step of step I) comprises the steps of: i) supplying the heated IPA-containing wastewater to the pervaporation membrane module; ii) condensing the IPA penetrating the permeation membrane module into the liquid phase; And iii) transferring the condensed IPA to the permeate tank.

The heated IPA-containing wastewater is characterized in that it is maintained at 30 ~ 60 ℃ by the heater.

The supply flow rate of the IPA-containing wastewater supplied to the permeation membrane module is characterized in that more than five times the permeate flow rate.

The reverse osmosis membrane separation process of step II) includes a) supplying the boosted IPA-containing wastewater to the reverse osmosis membrane module; And b) transferring the wastewater that has passed through the reverse osmosis membrane module to the permeate tank.

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

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

According to the combined membrane separation process of the present invention, IPA can be selectively separated from IPA cleaning wastewater and concentrated to be recycled by concentrating at least 30% by weight. The wastewater treatment plant can be treated as it is.

1 is a block diagram illustrating a continuous merge membrane separation process in accordance with the present invention.

Figure 2 is a block diagram showing a batch merge membrane separation process according to the present invention.

Hereinafter, the IPA is concentrated using the permeation membrane separation process according to the present invention, and at the same time, the combined membrane separation process for separating the IPA concentration into an appropriate concentration for wastewater treatment using the reverse osmosis membrane separation process will be described in detail with the accompanying drawings. Let's do it.

The present invention comprises the steps of: I) concentrating IPA from the IPA-containing wastewater through a permeation membrane separation process; And II) treating the wastewater from the IPA-containing wastewater through a reverse osmosis membrane separation process.

In addition, the pervaporation membrane separation process of step I) comprises the steps of: i) supplying the heated IPA-containing wastewater to the pervaporation membrane module; ii) condensing the IPA penetrating the permeation membrane module into the liquid phase; And iii) transferring the condensed IPA to the permeate tank; as shown in the continuous process block diagram of FIG. 1, first the IPA-containing wastewater (IPA solution) is transferred to the IPA solution tank 100. And the IPA solution of the IPA solution tank is heated by conventional heating means such as the heater 110. At this time, if the temperature of the IPA solution is less than 30 ℃ the permeation amount of the permeation membrane module is too small, if the temperature of the IPA solution exceeds 60 ℃ energy consumption is too large, the IPA solution is heated by the heater 110 It is preferable to make it hold | maintain at 30-60 degreeC.

Subsequently, the IPA solution heated to 30 to 60 ° C. is supplied to the permeation membrane module 150, where the process of sequentially passing the IPA solution supply pump 120, the solution filter 130, and the IPA solution flow meter 140 is accompanied. do. At this time, the supply flow rate of the IPA solution supplied to the permeation membrane module 150 is preferably adjusted to 5 times or more of the permeate flow rate. If the IPA solution is supplied to the permeation membrane module 150 at less than 5 times, the IPA concentration of the permeate solution passing through the permeation membrane module 150 is low and separation and concentration are not performed smoothly.

In this way, the IPA solution supplied to the permeation membrane module 150 has an action mechanism in which IPA is dissolved in the separation membrane, diffuses in the separation membrane, and permeates into the vapor phase. This action mechanism is one end of the permeation membrane module 150 is in contact with the IPA supply solution, the other end is in contact with the vapor pressure of the low permeate, low vapor pressure conditions can be made by applying a vacuum or flowing an inert carrier gas bar In general, in order to maintain the driving force of the pervaporation membrane separation process, a chemical potential, which is a driving force of the pervaporation membrane separation process, is generated within the pervaporation membrane to permeate the material through the membrane. By using the vacuum pump 170, the vacuum is maintained in the permeable part.

Next, the vapor phase IPA that has passed through the permeation evaporation membrane module 150 is condensed into a liquid phase in a conventional condenser 160, and the condensed liquid IPA is passed through the permeate solution flow meter 180 to the permeate solution tank 190. Transferred. The IPA solution obtained through this pervaporation membrane separation process can be recycled since it is concentrated to 30% or more.

Meanwhile, in the combined membrane separation process of the present invention, the reverse osmosis membrane separation process is performed at the same time. And b) transferring the wastewater that has passed through the reverse osmosis membrane module to a permeate tank, as shown in the continuous process block diagram of FIG. The IPA solution is boosted by being transferred to the IPA solution high pressure pump 220 via the solution filter 210. At this time, the supply pressure in the high-pressure pump 220 is preferably maintained at 10 ~ 70bar, when operating below 10bar, the driving force is low, the permeation rate of the reverse osmosis membrane is greatly reduced, if it exceeds 70bar long-term stability of the reverse osmosis membrane Since it falls, the IPA solution is adjusted to maintain a pressure 10 ~ 70bar by the high pressure pump 220.

Subsequently, the IPA solution boosted to 10 to 70 bar is supplied to the reverse osmosis membrane module 240 through the solution flow meter 230, and the wastewater that has passed through the reverse osmosis membrane module 240 passes through the permeate flowmeter 250 to transmit the permeate tank 260. Is transferred to. Wastewater (permeate) that is permeated through this reverse osmosis membrane separation process can be treated in the wastewater treatment plant as it is without dilution because the IPA concentration is 0.5% or less.

As described above, in actual operation of the continuous combined membrane separation process shown in FIG. 1, the tank 100 is filled with a predetermined amount of IPA-containing wastewater (IPA solution), and the IPA is separated using the pervaporation membrane separation process. And concentrating and simultaneously operating the reverse osmosis membrane separation process to permeate water (wastewater) to be transferred to the permeate tank 260, where the amount of IPA concentrate in the permeation membrane separation process and the permeate amount in the reverse osmosis membrane separation process are checked. The solution tank 100 is continuously replenished, and the capacity of the permeation membrane separation process and the reverse osmosis membrane separation process can be continuously operated according to the amount to be treated continuously (continuous wastewater generation amount).

Meanwhile, as another operation example, a batch type membrane separation process shown in FIG. 2 is also possible. IPA-containing wastewater (IPA solution) is filled in a predetermined amount into the tank 100, and IPA is used by using a pervaporation membrane separation process. After separating and concentrating, the concentration of the original IPA-containing wastewater is lowered below a certain concentration, the solution of IPA solution tank 100 is transferred to another IPA solution tank 200, and the transferred IPA-containing wastewater is reverse osmosis membrane separation. The water is permeated by the process and stored in the permeate tank 260. When water is removed from the IPA solution of the IPA solution tank 200 and the IPA is increased to a certain concentration, the water is transferred to the IPA solution tank 100 and again pervaporated. By repeatedly operating the membrane separation process, all of the IPA-containing wastewater is treated, and the permeate of the permeate tank 260 may be treated in a wastewater treatment plant due to a low concentration of IPA.

In addition, although not shown in the accompanying drawings, the IPA-containing wastewater (IPA solution) is filled in a predetermined amount in the tank 100, the IPA is separated and concentrated using a permeation membrane separation process, and at the same time, the reverse osmosis membrane separation process is also operated with water ( Waste water), and then, is transferred to the permeate tank 260, and then continues to operate to replenish the IPA-containing waste water when the level of the IPA solution tank 100 is below a certain amount, and the upper and lower levels of the IPA solution tank 100 Depending on the batch, a semi-batch type membrane separation process is also possible.

On the other hand, as the membrane material of the permeation evaporation membrane separation process included in the combined membrane separation process of the present invention, a silicon-based composite membrane in which an organic polysiloxane such as polydimethylsiloxane (PDMS) is coated on a porous support such as polyetherimide is preferred. The membrane material of the reverse osmosis membrane separation process is preferably a polyamide-based composite membrane in which a polyamide is coated on a porous support such as polysulfone, but is not limited thereto.

Hereinafter, specific embodiments will be described in detail.

(Example 1)

The IPA concentration of the wastewater containing IPA was fixed at 5.2% by weight, the feed flow rate was set at 80 liter per minute (LPM), and the temperature of the feed solution was changed to 35 ° C, 45 ° C, and 55 ° C, respectively. The membrane separation process was carried out, and Table 1 shows the IPA concentration and the permeate flow rate of the permeate solution according to the temperature of the feed solution by the pervaporation membrane separation process.

Table 1

Supply solution temperature ( ^o C)	Permeate solution concentration (% by weight)	Permeate Flow Rate (g / m ² hr)
35	45.6	510
45	41.5	752
55	38.4	1009

(Example 2)

A continuous combined membrane separation process was performed in the same manner as in Example 1, except that the IPA concentration of the IPA-containing wastewater was fixed at 8.7 wt%, and the IPA of the permeate solution according to the feed solution temperature according to the permeation evaporation membrane separation process is shown in Table 2. Concentration and flux were shown.

TABLE 2

Supply solution temperature ( ^o C)	Permeate solution concentration (% by weight)	Permeate Flow Rate (g / m ² hr)
35	53.2	630
45	48.8	895
55	43.5	1180

(Example 3)

The temperature of the feed solution was fixed at 35 and the feed flow rate was 20 LPM, and the IPA concentrations of the IPA-containing wastewater were changed to 5.2 wt%, 6.2 wt%, 7.3 wt% and 8.5 wt%, respectively. The membrane separation process was performed, and Table 3 shows the IPA concentration and permeate flow rate of the permeate solution (permeate) by the reverse osmosis membrane separation process.

TABLE 3

Feed solution concentration (% by weight)	Permeate (Permeate) IPA Concentration (% by weight)	Permeate Flow Rate (LPM)
5.2	0.31	1.20
6.2	0.35	1.12
7.3	0.41	0.98
8.5	0.50	0.89

As shown in Tables 1 and 2, according to the pervaporation membrane separation process according to Examples 1 and 2 of the combined membrane separation process of the present invention, when the temperature of the feed solution is the same, the IPA concentration of the IPA-containing wastewater may be higher. It can be seen that the IPA concentration and the permeate flow rate of the permeate solution increased more, and in all cases, the permeate solution was recycled because the IPA concentration of the permeate solution was higher than 38%.

In addition, as shown in Table 3, according to the reverse osmosis membrane separation process according to Example 3 of the combined membrane separation process of the present invention, when the IPA concentration (concentration of the feed solution) of the IPA-containing wastewater increases from 5.2% by weight to 8.5% by weight The permeate solution (permeate) slightly increases the permeate flow rate and the permeate flow rate decreases, but in all cases the permeate solution (permeate) is less than 0.5% by weight, so the permeate (permeate) is transferred to the wastewater treatment plant as it is. It was confirmed that it can be treated with wastewater.

Therefore, according to the combined membrane separation process of the present invention, IPA can be selectively separated from IPA cleaning wastewater and concentrated to be recycled by concentrating more than 30% by weight. It shows a remarkable effect that can be treated as it is in the wastewater treatment plant.

Claims

I) concentrating the IPA from the IPA containing wastewater through the permeation membrane separation process; And

II) treating the wastewater from the IPA-containing wastewater through a reverse osmosis membrane separation process.
According to claim 1, wherein the permeation membrane separation process of step I) comprises the steps of: i) supplying the heated IPA-containing wastewater to the permeation membrane module;

ii) condensing the IPA penetrating the permeation membrane module into the liquid phase; And

iii) transferring the condensed IPA to the permeate tank.
The combined membrane separation process according to claim 2, wherein the heated IPA-containing wastewater is maintained at 30 to 60 ° C by a heater.
The combined membrane separation process according to claim 2, wherein the supply flow rate of the IPA-containing wastewater supplied to the pervaporation membrane module is at least five times the permeate flow rate.
According to claim 1, wherein the reverse osmosis membrane separation step of step II) a) supplying the boosted IPA-containing wastewater to the reverse osmosis membrane module; And

b) transferring the wastewater that has passed through the reverse osmosis membrane module to a permeate tank.
The combined membrane separation process according to claim 5, wherein the boosted IPA-containing wastewater is maintained at 10 to 70 bar by a high pressure pump.
6. The combined membrane separation process according to claim 5, wherein the supply flow rate of the IPA-containing wastewater supplied to the reverse osmosis membrane module is three times or more than the permeate flow rate.
The combined membrane separation process according to claim 1 or 2, wherein the membrane material of the pervaporation membrane separation process is a silicon-based composite membrane.
The combined membrane separation process according to claim 1 or 5, wherein the membrane material of the reverse osmosis membrane separation process is a polyamide-based composite membrane.