JP3534015B2 - Stripping equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a stripping device for performing gas stripping such as ammonia stripping, and more particularly to a stripping device for stripping raw water in multiple stages.

[0002]

2. Description of the Related Art In equipment that handles combustion gas, such as a thermal power plant, (NH ₄ ) ₂ SO
A scale consisting mainly of ₄ adheres. This scale is regularly and irregularly washed and removed by washing with water or the like. A large amount of NH ₄ -N is contained in the wastewater generated by these operations.
(Ammonia nitrogen) is included.

As a device for stripping ammonia-containing water in multiple stages, Japanese Patent Laid-Open No. 10-57947 discloses a stripping device schematically shown in FIG.

This stripping device 71 includes a first chamber 7
5, the second chamber 76 and the third chamber 77. The ammonia-containing wastewater supplied into the first chamber 75 moves to the second chamber 76 and the third chamber 77 while overflowing after the alkaline agent is added. In each of the chambers 75 to 77, a disk 79 that rotates at a high speed by a motor 78 is provided so that the lower part is immersed in the ammonia-containing wastewater, and the disk 79 serves as a scraping member that scrapes up the ammonia-containing wastewater and vaporizes it. Ammonia is released into the gas phase by making it finer and bringing it into contact with gas. In each room 75, 76, 77,
The air supplied from the third chamber 77 into the gas phase flows into the second chamber 76 and the first chamber 75 so as to face the flow of the ammonia-containing wastewater. The air flow is taken out, and the ammonia stripped water is taken out from the third chamber 77.

[0005]

In the stripping apparatus shown in FIG. 2, the waste water containing ammonia is contained in the first chamber 75.
To the second chamber 76 and then to the third chamber 77 while sequentially overflowing, so that a part of the water flows to the adjacent chamber in a short-circuited manner, and the ammonia stripping efficiency decreases.

An object of the present invention is to provide a stripping device which can perform a stripping process with extremely high efficiency.

[0007]

The stripping apparatus of the present invention includes a connecting body of a plurality of booths arranged so that gas sequentially flows, and a booth in each booth other than the booth on the most downstream side in the gas flowing direction. Watering means installed on the top respectively,
A means for supplying treated water to the booth on the most downstream side in the gas flow direction, and a means for supplying water in each booth other than the booth on the most upstream side in the gas flow direction to the sprinkling means in the booth on the upstream side , A means for removing the stripped water from the booth on the most upstream side in the gas flow direction .
The booth is a tripping device
It is formed by partitioning with partition walls
The upper part of the partition has an opening for gas flow.
Guide means for flowing gas downward from the opening
Is provided.

In such a stripping device, the water in each booth is sprayed by the spraying means in the adjacent booth on the upstream side in the gas flow direction. Therefore, since the water in the booth does not flow to the adjacent booth due to the overflow, the water to be treated does not flow in a short circuit between the booths, and the stripping process is extremely efficient.

[0009] In the present invention, in order to compact the equipment, booth has been formed by partitioning the housing by a partition wall, that have openings for gas flow is provided above the partition wall. Further, in order to extend the gas retention time in the booth by flowing the gas downward from this opening and to prevent the spray water from leaking to the adjacent booth, guide means such as louvers and guide vanes are provided. is not that.

In the present invention, in order to increase the gas-liquid contact area, it is preferable that the sprinkling means sprays water.

When ammonia stripping is carried out by the apparatus of the present invention, it is desirable to provide a means for adding an alkaline solution such as an aqueous solution of sodium hydroxide to the raw water in order to make the raw water alkaline. Further, if ammonia in the water to be treated is diffused into the air, the pH in the water to be treated will decrease, so it is preferable to provide a means for adding an alkaline solution such as sodium hydroxide to the booth in the middle.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.

Ammonia stripping housing 10
Is provided with an air inlet 11 at one end side in the longitudinal direction,
An air outlet 12 is provided on the other end side. A partition wall 13 separates the inlet 11 and the outlet 12 into a plurality of chambers (7 chambers in this embodiment) booths 1 to 7. At the top of each partition wall 13, an opening 15 is provided which connects adjacent booths to each other, and each opening 15 is provided with a louver 14 for flowing air downward. The air introduced into the lower part of the seventh booth 7 from the introduction port 11 sequentially passes through the booths 7-1 through the openings 15 and flows out from the outflow port 12. Exhaust equipment (not shown) having a damper and an exhaust fan is connected to the outlet 12.

Raw water containing ammonia is supplied to the flow control valve 17
Further, the raw water is introduced into the first booth 1 through the raw water introducing pipe 16 having the line mixer 18.

At the bottom of the first to sixth booths 1 to 6,
One end of liquid supply pipes (spray lines) 31 to 36 having liquid supply pumps 21 to 26 is connected. A pressure gauge (not shown) is provided on each of the pipes (spray lines) 31 to 36. Spray nozzles 42 to 47 are arranged in the upper portions of the second to seventh booths 2 to 7, respectively, and the other ends of the pipes 31 to 36 are connected to the spray nozzles 42 to 47, respectively.
~ 47.

The raw water in the first booth 1 is supplied to the spray nozzle 42 through the pump 21 and the pipe 31, and the second water is supplied to the spray nozzle 42.
It is sprayed into the booth 2 and comes into gas-liquid contact, and is subjected to ammonia stripping treatment. The water that has dropped to the lower part of the second booth 2 is supplied to the spray nozzle 43 through the pump 22 and the pipe 32, is sprayed into the third booth 3 and comes into gas-liquid contact, and is subjected to ammonia stripping treatment. The water dropped to the lower part of the third booth 3 is similarly pumps 23 to 26, pipes 33 to 36 and spray nozzles 44 to.
Each booth 4 to 7 is sprayed via 47 and is subjected to an ammonia stripping process.

The water that has dropped to the lower part of the seventh booth 7 is taken out from the bottom of the booth 7 through the drainage pump 27 and the pipe 37 as deammonified treated water.

In order to make the pH of the raw water alkaline and enhance the ammonia stripping efficiency, the raw water pipe 1
Sodium hydroxide aqueous solution was added to the tank 6 from the tank 50 through the pump 51, the flow rate control valve 52 and the pipe 53, and was mixed with the raw water in the line mixer 18, and then the alkaline raw water was introduced into the first booth 1. It is configured. The first booth 1 is provided with a pH meter 57, and the valve 52 is controlled so that the pH detected by the pH meter 57 falls within a predetermined range.

As the raw water (water to be treated) is subjected to the ammonia stripping treatment in each booth, the pH of the water to be treated is gradually lowered. Therefore, in this embodiment, the aqueous sodium hydroxide solution in the tank 50 is supplied to the third booth 3 through the pipe 54 and the flow rate so that the pH detected by the pH meter 58 installed in the fourth booth on the way is within a predetermined range. Control valve 55
Is added via. The valve 55 is controlled based on the detection value of the pH meter 58.

Further, in this embodiment, the temperature of the raw water in the first booth 1 is detected by a thermometer (TI), and the temperature in the first booth 1 is kept within a predetermined range. Steam is blown into the water through the steam pipe 60.
The TI is also provided in the fourth booth 4 and the seventh booth 7 for temperature monitoring (not shown). Further, steam is also added from the steam pipe 61 to the air supplied from the inlet 11 into the seventh booth 7 to raise the air temperature and enhance the stripping efficiency.

The flow rate of raw water is a raw water flow meter (not shown).
Is adjusted by the flow rate control valve 17. The air flow rate is adjusted by an air flow meter and a damper (not shown).

The balance of the spray amount in each booth 2 to 7 is uniformly controlled based on the pressure gauge (not shown) installed in each spray line 31 to 36. As a countermeasure in the event of imbalance in the spray amount, a small-diameter communication pipe (not shown) for equalizing the liquid depth in each booth is installed between the booths.

This stripping device is of a countercurrent contact type, in which ammonia-free air comes into contact with the wastewater having the lowest ammonia concentration at the 7th booth, and then the air having the increased ammonia concentration is successively introduced. The wastewater having a high concentration of ammonia comes into contact with the wastewater, and the air having a high concentration of ammonia comes into contact with the raw water in the second booth 2 to perform ammonia stripping of the raw water. Therefore, stripping is performed until the ammonia concentration in the water becomes extremely low.

In the above embodiment, seven booths 1 to 7 are provided, but it is clear that the number of booths may be another number. When removing about 95% of the ammonia in the waste water, the number of booths is preferably about 10.

In the above embodiment, the aqueous sodium hydroxide solution is additionally added only to the third booth 3 on the way, but the aqueous sodium hydroxide solution may be added to the other booths on the way. . Further, the sodium hydroxide aqueous solution may be added to a plurality of booths on the way, or the sodium hydroxide aqueous solution may be added to all the booths on the way.

In the above-mentioned embodiment, the spray nozzle is not provided in the first booth 1. However, the spray nozzle is also provided in the first booth 1, and the raw water to which the sodium hydroxide aqueous solution is added is supplied to the first booth 1. The spray nozzle may be supplied with water to perform the stripping process in the first booth 1. In this case, the gas outlet 1 of the housing 10
A mist collecting means may be provided after 2.

In the above embodiment, the raw water and air are heated by steam, but an electric heater may be used.

When the raw water contains a large amount of metal ions, if the pH is adjusted to the alkaline side, the metal ions will precipitate as hydroxides. When this hydroxide makes gas-liquid contact with a scrubber or the like having a filling material, it adheres to the filling material and causes obstacles such as clogging, so that efficient stripping cannot be obtained. Further, even in the stripping equipment for overflowing the waste water as in JP-A-10-57947, the retention time of the waste water (gas-liquid contact time) is reduced by the precipitation of the hydroxide in the booth and the reduction of the tank volume. Efficient stripping cannot be performed because the amount of wastewater decreases or the wastewater short-passes.

On the other hand, in the spray booth according to this embodiment, no filling material is used, and gas-liquid contact is performed only by spraying from the nozzle, and water that settles in the booth liquid depth is obtained by using the spray pump. Since the oxide is mixed with the waste water and forcibly transferred to the next booth and sprayed, hydroxide sedimentation and retention in the booth is prevented.

In the stripping apparatus according to this embodiment, ammonia can be removed in a state where sludge contained in raw water, iron hydroxide and other hydroxides generated after pH adjustment are mixed. This stripping device can be processed in a small space and can be a portable device by a truck. This stripping device can obtain a high removal rate at a relatively low temperature (40 ° C.). Further, the removal rate can be easily adjusted by adjusting the exhaust gas amount, the processing liquid amount, and the processing temperature.

[0031]

As described above, according to the stripping apparatus of the present invention, extremely efficient stripping processing can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a stripping device according to an embodiment.

FIG. 2 is a configuration diagram of a stripping device according to a conventional example.

[Explanation of symbols]

1-7 booth 10 housing 11 entrance 12 Outlet 13 partitions 14 louvers 15 openings 18 line mixer 21-27 pump 31-36 Piping (Spray line) 42-47 spray nozzle

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Daisuke Ikeda 2-2-22 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Kurita Engineering Co., Ltd. (72) Masahiro Kubo 2-2- Kitahama, Chuo-ku, Osaka City, Osaka Prefecture 22 Kurita Engineering Co., Ltd. (56) Reference JP-A-62-186984 (JP, A) JP-A-10-57947 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 1/20 B01D 19/00

Claims (2)

(57) [Claims] 1. A connection body of a plurality of booths arranged so that gas sequentially flows, sprinkling means installed in an upper part of each booth other than the booth on the most downstream side in the gas flow direction, and gas flow Means for supplying water to be treated to the booth on the most downstream side in the direction, means for supplying water in each booth other than the booth on the most upstream side in the gas flow direction to the sprinkling means in the upstream booth, and gas A stripping device comprising means for taking out stripped water from the booth on the most upstream side in the flow direction , wherein the booth defines a housing with partition walls.
Which is formed from
Is provided with guide means for downwardly flowing the gas from the opening.
Stripping device characterized by being stripped. Wherein Oite to claim 1, sprinkling means stripping apparatus, characterized in that spraying water.