Concentration method for amine waste water

Abstract

To propose a concentration method for amine waste water without requiring large equipment and with low treatment cost.SOLUTION: A concentration method for amine waste water of the present invention is characterized in that amine waste water to be concentrated is retained in a raw water tank, the retained amine waste water is dried by a rotary disk type drier to evaporate moisture in the amine waste water and to recover nonvolatile components in the amine waste water, the recovered nonvolatile components are returned to the raw water tank, and the amine waste water is circulated between the raw water tank and the rotary disk type drier. The concentration method is further characterized by using the rotary disk type drier for concentration of the amine waste water and by circulating the amine waste water for concentration.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for concentrating an amine waste liquid discharged from the cleaning of semiconductors or the like. [Background technology]

[0002] Amine waste liquid is discharged during the cleaning of semiconductors, etc. Conventionally, the amine waste liquid has been treated by biological treatment (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-51890 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the waste liquid treatment method using biological treatment disclosed in Patent Document 1, in order to treat a large amount of amine waste liquid, the treatment facility must be large in scale, which poses the problem of the need for large-scale equipment and high treatment costs. A typical method for treating amine waste liquid is to have it collected by a waste treatment specialist and incinerated. In recent years, there has been a demand for concentrating and reducing the volume of the waste liquid at the source of its discharge so that it can be efficiently collected by waste treatment specialists. [Means for solving the problem]

[0005] The method for concentrating an amine waste liquid according to the present invention is characterized in that the amine waste liquid to be concentrated is stored in a raw water tank, the stored amine waste liquid is dried in a rotary disk type dryer to evaporate water in the amine waste liquid and recover non-volatile components in the amine waste liquid, the recovered non-volatile components are returned to the raw water tank, and the amine waste liquid is circulated between the raw water tank and the rotary disk type dryer. [Brief description of the drawings]

[0006] [Figure 1] 1 is a flow chart for explaining one embodiment of a method for concentrating an amine waste liquid according to the present invention. [Diagram 2] FIG. 1 is a diagram for explaining one embodiment of a concentrating device used in the method for concentrating an amine waste liquid according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] <Method for concentrating amine waste liquid according to the present invention> An embodiment of the method for concentrating an amine waste liquid according to the present invention will be described with reference to the drawings. In the example shown in Fig. 1 and Fig. 2, the dimensions of each member, particularly the height dimension, are shown in dimensions different from the actual dimensions in order to make the features of the present invention better understandable.

[0008] Fig. 1 is a flow chart for explaining one embodiment of the method for concentrating amine waste liquid according to the present invention. To explain one embodiment of the method for concentrating amine waste liquid according to the present invention with reference to Fig. 1, first, the amine waste liquid before concentration is stored in a raw water tank 1. The weight of the raw water tank 1 is constantly measured by a weight measuring device 2, and it is monitored whether or not a target concentration rate has been reached. Whether or not the target concentration rate has been reached is determined by, for example, when the target concentration rate is 2 times, it is determined that the amine waste liquid has been concentrated by 2 times when the amount (weight) of the amine waste liquid in the raw water tank 1 becomes 1 / 2.

[0009] Next, the amine waste liquid to be concentrated stored in the raw water tank 1 is dried in a rotating disk type drying device (CD dryer) 3. Drying is performed by supplying steam to the disks of the rotating disk type drying device 3 to heat it. This drying evaporates the water in the amine waste liquid and recovers the non-volatile components in the amine waste liquid. The recovered non-volatile components are then returned to the raw water tank 1. Through the above process, the amine waste liquid is circulated between the raw water tank 1 and the rotating disk type drying device 3.

[0010] When the amine waste liquid is circulated in this manner, even if the non-volatile components of the amine waste liquid are returned to the raw water tank 1, the amount of concentrated amine liquid in the raw water tank 1 gradually decreases because the moisture evaporates due to drying in the rotating disk-type dryer 3. The weight measuring device 2 constantly measures this change, and when the amount of amine waste liquid in the raw water tank 1 reaches a predetermined concentration rate, it determines that the concentration of the amine waste liquid is complete and stops drying the amine waste liquid in the rotating disk-type dryer 3.

[0011] Next, when it is determined that the concentration of the amine waste liquid has been completed and the drying of the amine waste liquid in the rotating disk type dryer 3 is interrupted, a signal is sent from the weight measuring device 2 to open the valve 4 provided in the flow path connecting the rotating disk type dryer 3 and the treated water tank 5. As a result, the amine concentrated liquid in the rotating disk type dryer 3 is stored in the treated water tank 5, and then the treatment of the amine concentrated liquid is entrusted to a waste treatment specialist.

[0012] The water evaporated from the rotary disk type dryer 3 is supplied to a condenser 7 via a mist separator 6, where the evaporated material is cooled and liquefied to produce distilled water. The distilled water obtained is biologically treated by a conventionally known method. The remaining evaporated material is absorbed in a scrubber 8.

[0013] In the above-mentioned method for concentrating an amine waste liquid of the present invention, when the concentration rate of the amine waste liquid is targeted to be 2 times, for example, it is preferable to set the disk temperature, the disk rotation speed, and the circulating flow rate of the amine waste liquid relative to the disk in the rotating disk type drying device 3 to predetermined values.

[0014] Specifically, first, it is preferable to set the temperature of the disk of the rotary disk type drying device 3 to 120 to 130°C. The reason why it is preferable to set the temperature of the disk to 120 to 130°C is that if the temperature of the disk is less than 120°C, it may cause a failure to discharge the drained steam. Also, if the temperature of the disk exceeds 130°C, the thermal decomposition and evaporation of the amines in the amine waste liquid 12 on the disk progresses, and the amount of amines contained in the distilled water increases. As a result, the obtained distilled water may not be treatable by biological treatment.

[0015] The disk rotation speed of the rotating disk type drying device 3 is preferably 10 to 20 rpm. The reason why the disk rotation speed is preferably 10 to 20 rpm is that if the disk rotation speed is less than 10 rpm, the contact area between the disk and the amine waste liquid becomes small, and the amount of amines evaporated from the amine waste liquid on the disk may be too small. Also, if the disk rotation speed exceeds 20 rpm, the equipment may vibrate too much and may not operate normally.

[0016] Furthermore, when the amine waste liquid is supplied to the disk of the rotary disk type drying device 3, the circulation flow rate of the amine waste liquid is preferably 13 to 45 L / min. The reason why the circulation flow rate is preferably 13 to 45 L / min is that if the circulation flow rate is less than 13 L / min, the amine waste liquid may not come into contact with the disk and normal treatment may not be performed. Also, if the circulation flow rate exceeds 45 L / min, the amine waste liquid may scatter and flow out of the system, and normal treatment may not be performed.

[0017] According to the method for concentrating amine waste liquid of the present invention described with reference to FIG. 1 above, the rotary disk type dryer 3 is used, and the amine waste liquid is concentrated by circulating the amine waste liquid between the raw water tank 1 and the rotary disk type dryer 3. Therefore, the amine waste liquid can be concentrated to a desired concentration ratio even if the disk temperature, the disk rotation speed, and the circulation flow rate of the amine waste liquid are changed.

[0018] In addition, in the method for concentrating amine waste liquid according to the present invention, when the disk temperature is 130° C., the disk rotation speed is 20 rpm, and the circulation flow rate of the amine waste liquid is 45 L / min, the amount of amine waste liquid that can be treated per unit time is maximized.

[0019] Furthermore, in the method for concentrating an amine waste liquid according to the present invention, when the disk temperature is 120° C., the disk rotation speed is 20 rpm, and the circulation flow rate of the amine waste liquid is 45 L / min, the amount of evaporation of amines is minimized.

[0020] <One embodiment of a concentrating apparatus used in the method for concentrating amine waste liquid according to the present invention> Fig. 2 is a diagram for explaining one embodiment of a concentrating apparatus used in the method for concentrating an amine waste liquid of the present invention. In Fig. 2, the concentrating apparatus 10 for an amine waste liquid used in the method for concentrating an amine waste liquid of the present invention is composed of a rotary disk type drying apparatus 11, a raw water tank 13 for storing an amine waste liquid 12, and a jig 14 provided between the rotary disk type drying apparatus 11 and the raw water tank 13. The rotary disk type drying apparatus 11 also includes a circulation tank 15, a feed pipe 16, a disk 17, and a scraper 18.

[0021] The amine waste liquid 12 in the raw water tank 13 is supplied to the circulation tank 15 by the operation of a pump 21 based on the result of measurement of the liquid level by a liquid level sensor 22 provided in the circulation tank 15. The amine waste liquid 12 supplied to the circulation tank 15 is sprayed onto the surface of a disk 17 from the tip of a feed pipe 16 by the operation of a pump 23. High-temperature steam is supplied to the center of the disk 17 to heat it. The amine waste liquid 12 sprayed onto the surface of the disk 17 is dried by the heat and rotational motion of the disk 17.

[0022] The water in the amine waste liquid 12 dried by the disks 17 evaporates and is converted into distilled water by the action of a fan 24 in a mist separator 25 (including a cooling condenser), which is then biologically treated. In addition, the non-volatile components of the amine waste liquid 12 dried by the disks 17 are scraped off the surface of the disks 17 by a scraper 18 and collected, and are returned to the amine waste liquid 12 in the raw water tank 13 via a jig 14. When the concentration of the amine waste liquid 12 is complete, the concentrated liquid in the circulation tank 15 is supplied to the outside and treated externally by a waste treatment specialist.

[0023] According to the amine waste liquid concentrating device 10 used in the above-mentioned amine waste liquid concentrating method of the present invention, the non-volatile components on the surface of the disk 17 recovered by the scraper 18 are returned to the raw water tank 13 by the jig 14, and the amine waste liquid 12 can be concentrated by circulating between the raw water tank 13 and the rotating disk type drying device 11. Therefore, it can be suitably used in the amine waste liquid concentrating method of the present invention. As the rotating disk type drying device 11, a commercially available one can be used, for example, a CD dryer manufactured by Nishimura Iron Works Co., Ltd. [Explanation of symbols]

[0024] 1, 13 Raw water tank 2 Weight measuring device 3, 11 Rotating disk type drying device 4 Valve 5 Treatment tank 6, 25 Mist separator 7 Capacitor 8. Scrubber 10 Concentrator 12 Amine waste liquid 14 Jig 15 Circulation tank 16 Feed pipe 17 Discs 18 Scraper 21, 23 Pump 22 Liquid level sensor 24 Fans

Claims

1. The amine waste liquid to be concentrated is stored in the raw water tank. The stored amine waste liquid is dried in a rotary disk type dryer to evaporate the water in the amine waste liquid and recover the non-volatile components in the amine waste liquid. The recovered non-volatile components are returned to the raw water tank. The amine waste liquid is circulated between the raw water tank and the rotary disk type dryer.

2. A method for concentrating an amine waste liquid comprising the steps of:

2. The method for concentrating an amine waste liquid according to claim 1, The temperature of the disk of the rotary disk type drying device is 120 to 130°C.

2. A method for concentrating an amine waste liquid comprising the steps of:

3. The method for concentrating an amine waste liquid according to claim 1, The rotation speed of the disk of the rotating disk type drying device is set to 10 to 20 rpm.

2. A method for concentrating an amine waste liquid comprising the steps of:

4. The method for concentrating an amine waste liquid according to claim 1, When the amine waste liquid is supplied to the disk of the rotary disk type drying device, the circulation flow rate of the amine waste liquid is 13 to 45 L / min.

2. A method for concentrating an amine waste liquid comprising the steps of:

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