JP4342280B2 - Alkaline wastewater neutralizer - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an alkaline wastewater neutralization treatment apparatus that neutralizes by bringing combustion exhaust gas into contact with alkaline wastewater.

As a neutralization treatment device for neutralizing alkaline wastewater, a device equipped with a neutralization treatment tank for neutralizing wastewater using combustion exhaust gas discharged from a gas turbine or the like has been proposed (for example, a patent) Reference 1). The neutralization treatment tank in this neutralization treatment apparatus includes a neutralization treatment chamber to which alkaline drainage is supplied, and an air diffusion box is provided at the bottom of the neutralization treatment chamber. A plate-like member provided with a vent is attached. The combustion exhaust gas is supplied to the diffuser box, and the supplied combustion exhaust gas is supplied in the form of bubbles to the alkaline drainage in the neutralization chamber through a number of vents. The alkaline drainage is neutralized by the gas-liquid contact. That is, the next reaction by gas-liquid contact,
CO ₂ + H ₂ O → H ₂ CO ₃
H ₂ CO ₃ → CO ₃ ²⁻ + 2H ⁺
And the alkaline waste water can be neutralized by carbon dioxide contained in the combustion exhaust gas.

JP 2001-157896 A

  In the conventional neutralization tank, the combustion exhaust gas fed to the diffuser box is supplied to the alkaline waste water in the neutralization chamber through, for example, a circular vent hole. The gas-liquid contact between the alkaline drainage and the alkaline drainage was not performed sufficiently efficiently, and the alkaline drainage could only be neutralized to a certain extent.

  An object of the present invention is to provide an alkaline wastewater neutralization treatment apparatus that can sufficiently neutralize alkaline wastewater using combustion exhaust gas.

The alkaline wastewater neutralization treatment apparatus according to claim 1 of the present invention is a drainage tank for storing alkaline wastewater, a neutralization treatment tank for neutralizing alkaline wastewater, and combustion exhaust gas in the neutralization treatment tank. Exhaust gas feeding means for feeding, feeding waste water from the drainage tank to the neutralization treatment tank, and combustion exhaust gas from the exhaust gas feeding means in the neutralization treatment tank An alkaline wastewater neutralization treatment apparatus that neutralizes by contacting with alkaline wastewater,
The neutralization treatment tank includes an exhaust gas chamber into which combustion exhaust gas from the exhaust gas supply unit flows, and a gas-liquid contact chamber into which alkaline drainage from the drain tank flows, and the exhaust gas chamber and the A ventilation partition wall is provided between the gas-liquid contact chamber, a plurality of ventilation slits extending in an oblique direction are provided in the ventilation partition wall, and combustion exhaust gas from the exhaust gas chamber is supplied to the plurality of ventilation gas. The gas-liquid contact chamber is fed into the gas-liquid contact chamber through a slit.

  Moreover, in the alkaline waste water neutralization treatment apparatus according to claim 2 of the present invention, the gas-liquid contact chamber of the neutralization treatment tank includes a lower gas-liquid contact chamber disposed above the exhaust gas chamber, The upper gas-liquid contact chamber is disposed above the lower gas-liquid contact chamber, and a lower ventilation partition wall is provided between the exhaust gas chamber and the lower gas-liquid contact chamber. And the upper gas / liquid contact chamber are provided with an upper ventilation partition wall, the lower ventilation partition wall and the upper ventilation partition wall are provided with a plurality of ventilation slits extending in an oblique direction, The upper gas-liquid contact chamber flows through the lower gas-liquid contact chamber, and the combustion exhaust gas flows from the exhaust gas chamber through the lower gas-liquid contact chamber to the upper gas-liquid contact chamber.

  Moreover, in the alkaline waste water neutralization processing apparatus according to claim 3 of the present invention, the lower gas-liquid contact chamber and the upper gas-liquid contact chamber communicate with each other by a communication pipe structure, and the communication pipe structure stores the waste water. A U-shaped tube portion having one end communicating with the upper gas-liquid contact chamber, and the other end communicating with the lower gas-liquid contact chamber via a connecting tube portion extending downward. Further, the other end of the U-shaped tube portion is communicated with the upper gas-liquid contact chamber through a gas vent tube portion extending upward.

  In the alkaline wastewater neutralization treatment apparatus according to claim 4 of the present invention, the ratio (S1 / S2) of the slit area S1 of the plurality of ventilation slits to the area S2 of the ventilation partition wall is 1/70 to 1. / 30, and the passage linear velocity of the combustion exhaust gas passing through the plurality of ventilation slits is 6 to 20 m / sec.

  Moreover, in the alkaline wastewater neutralization processing apparatus according to claim 5 of the present invention, the exhaust gas supply means includes an exhaust gas supply pipe for guiding the exhaust gas to the exhaust gas chamber of the neutralization tank. One end of the exhaust gas supply pipe extends into the exhaust gas chamber, and an open / close flapper is provided at one end of the exhaust gas supply pipe so that the exhaust gas can be opened and closed from the exhaust gas supply means to the exhaust gas chamber. When the exhaust gas is fed, the opening / closing flapper is held open by the supply pressure of the combustion exhaust gas, and when the supply of the combustion exhaust gas from the exhaust gas feeding means is stopped, the weight of the opening / closing flapper is reduced. Thus, the open / close flapper is maintained in a closed state.

  According to the alkaline wastewater neutralization treatment apparatus of the first aspect of the present invention, the neutralization tank for neutralizing the alkaline wastewater includes the exhaust gas chamber and the gas-liquid contact chamber, and the combustion exhaust gas is sent to the exhaust gas chamber. The alkaline drainage is fed to the gas-liquid contact chamber. Since the exhaust gas chamber and the gas-liquid contact chamber are partitioned through a ventilation partition wall provided with a plurality of ventilation slits extending in an oblique direction, the combustion exhaust gas supplied to the exhaust gas chamber has a large number of ventilation holes. Air bubbles are fed into the gas-liquid contact chamber through the slit, and the alkaline drainage can be neutralized by gas-liquid contact between the combustion exhaust gas and the alkaline drainage. In addition, since the combustion exhaust gas flows through a ventilation slit extending in an oblique direction, the combustion exhaust gas becomes a small bubble and is sent to the alkaline drainage in the gas-liquid contact chamber, thereby increasing the gas-liquid contact efficiency. The alkaline drainage can be neutralized as desired.

  According to the alkaline wastewater neutralization treatment apparatus of the second aspect of the present invention, the gas-liquid contact chamber is composed of the lower gas-liquid contact chamber and the upper gas-liquid contact chamber, and the exhaust gas chamber and the lower gas-liquid contact chamber Is provided with a lower ventilation partition wall, and an upper ventilation partition wall is provided between the lower gas-liquid contact chamber and the upper gas-liquid contact chamber. Since the alkaline waste water is neutralized by the chamber, the neutralization tank can be made compact while maintaining a desired neutralization capacity. In addition, while alkaline drainage flows from the upper gas-liquid contact chamber to the lower gas-liquid contact chamber, the combustion exhaust gas fed to the exhaust gas chamber flows from the lower gas-liquid contact chamber to the upper gas-liquid contact chamber. In the gas-liquid contact chamber, the combustion exhaust gas from the exhaust gas chamber comes into contact with the alkaline drainage neutralized in the upper gas-liquid contact chamber, and thus the alkaline drainage can be sufficiently neutralized. it can.

  Moreover, according to the alkaline waste water neutralization treatment apparatus according to claim 3 of the present invention, the lower gas-liquid contact chamber and the upper gas-liquid contact chamber are connected by a communication pipe structure, and the U-shaped tube of this communication pipe structure One end of the part is connected to the upper gas-liquid contact chamber, and the other end communicates with the lower gas-liquid contact chamber via a connecting pipe portion that extends downward. The alkaline wastewater is fed to the lower gas-liquid contact chamber through the U-shaped tube portion and the connecting tube portion. Moreover, since the other end part of the U-shaped pipe part is connected to the upper gas-liquid contact chamber via the gas vent pipe part, the gas accumulated in the other end part of the U-shaped pipe part (separated from the alkaline drainage) Combustion exhaust gas) flows to the upper gas-liquid contact chamber through the gas vent pipe. Also, the upper gas-liquid contact chamber and the lower gas-liquid contact chamber are maintained in communication with each other via the connecting pipe portion and the gas vent pipe portion, and the lower gas-liquid contact chamber and the upper gas-liquid contact chamber are maintained at the same pressure. Can do.

  Moreover, according to the alkaline waste water neutralization treatment apparatus of the fourth aspect of the present invention, the ratio (S1 / S2) of the slit area S1 of the plurality of ventilation slits to the area S2 of the ventilation partition wall is 1/70 to 1. Therefore, the combustion exhaust gas can be made into bubbles through the ventilation slit and brought into contact with the alkaline waste water in the gas-liquid contact chamber almost uniformly and neutralized as required. When this ratio (S1 / S2) is smaller than 1/70, the combustion exhaust gas does not substantially contact the alkaline waste water in the gas-liquid contact chamber, and when this ratio (S1 / S2) is larger than 1/30. It does not come into contact with alkaline wastewater almost uniformly, and the neutralization capacity decreases. Furthermore, since the passage linear velocity of the combustion exhaust gas passing through the plurality of ventilation slits is 6 to 20 m / second, the combustion exhaust gas can be supplied to the gas-liquid contact chamber as required through the ventilation slit. If this passage linear velocity is less than 6 m / sec, the pressure of the combustion exhaust gas flowing through the ventilation slit becomes too low, and there is a risk that alkaline drainage will fall through the ventilation slit, and if this passage linear velocity is greater than 20 m / sec, The pressure of the combustion exhaust gas flowing through the ventilation slit becomes excessive, and there is a risk that alkaline drainage will blow off.

  Further, according to the alkaline wastewater neutralization treatment apparatus of the fifth aspect of the present invention, an open / close flapper is provided at one end of the exhaust gas supply pipe so as to be openable and closable. Since the open state is maintained by the supply pressure, the combustion exhaust gas can be supplied to the exhaust gas chamber. Also, when combustion exhaust gas supply stops, it is kept closed by its own weight, so even if alkaline drainage falls from the gas-liquid contact chamber, the fallen alkaline drainage is prevented from flowing into the exhaust gas delivery pipe can do.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS An embodiment of an alkaline wastewater neutralizing apparatus according to the invention will be described below with reference to the accompanying drawings. FIG. 1 is a simplified view schematically showing the entire alkaline wastewater neutralization treatment apparatus of one embodiment, and FIG. 2 is a cross-sectional view showing a neutralization treatment tank in the neutralization treatment apparatus of FIG. 3 is a partial cross-sectional view showing one end portion of the exhaust gas supply pipe in the neutralization treatment tank of FIG. 2, and FIG. 4 shows a part of the ventilation partition wall in the neutralization treatment tank of FIG. 5 is a cross-sectional view, and FIG. 5 is a cross-sectional view of the upper gas-liquid contact chamber of FIG. 2 as viewed from above.

  1 and 2, the illustrated alkaline wastewater neutralization apparatus includes a neutralization treatment tank 2 that neutralizes the exhaust gas by contacting the combustion exhaust gas with alkaline wastewater. In this embodiment, the neutralization tank 2 includes a lower housing 4 and an upper housing 6, an exhaust gas chamber 8 is defined in the lower housing 4, and a lower gas / liquid contact chamber 10 and an upper gas / liquid contact are formed in the upper housing 6. A chamber 12 is defined.

  Combustion exhaust gas is supplied to the exhaust gas chamber 8. In this embodiment, the combustion exhaust gas from the gas engine 14 of the cogeneration system is used. A generator 16 is drivingly connected to the output shaft of the gas engine 14, and the generator 16 is operated by the gas engine 14 to generate power, and the generated power is consumed by the power load. The combustion exhaust gas from the gas engine 14 flows through the exhaust heat recovery heat exchanger 18, and heat is exchanged with water in the exhaust heat recovery heat exchanger 18, and the heat of the combustion exhaust gas is recovered as hot water. . The combustion exhaust gas after exhaust heat recovery is discharged to the outside, but a part of the combustion exhaust gas discharged to the outside is sent to the exhaust gas chamber 8 of the neutralization treatment tank 2 through the exhaust gas feeding means 20. The The exhaust gas supply means 20 includes an exhaust gas supply pipe 22 for guiding the combustion exhaust gas after heat exchange to the exhaust gas chamber 8, and a supply blower 24 provided in the exhaust gas supply pipe 22. Thus, a part of the combustion exhaust gas after the heat exchange is fed to the exhaust gas chamber 8 of the neutralization treatment tank 2 through the exhaust gas feed pipe 22 by the suction action of the feed blower 24.

  In this embodiment, the alkaline waste water is neutralized by using the combustion exhaust gas from the gas engine 14 as will be described later. However, the present invention is not limited to this, and the combustion exhaust gas such as a gas fired boiler or a heavy oil fired boiler is used. Gas can also be used. The content of carbon dioxide in the combustion exhaust gas discharged from the gas engine 14 of the cogeneration system is around 6%, and the content of carbon dioxide in the combustion exhaust gas discharged from the gas fired boiler and heavy oil fired boiler is Combustion exhaust gas having about 10 to 12% and a carbon dioxide content of about 6 to 12% can be used.

  In this neutralization treatment tank 2, a lower gas / liquid contact chamber 10 is disposed above the exhaust gas chamber 8, and an upper gas / liquid contact chamber 12 is disposed above the lower gas / liquid contact chamber 10. A lower ventilation partition wall 26 is provided between the lower gas-liquid contact chamber 10 and the lower gas-liquid contact chamber 10, and an upper ventilation partition wall 28 is provided between the lower gas-liquid contact chamber 10 and the upper gas-liquid contact chamber 12. In this embodiment, a supply port 30 for supplying alkaline drainage to be neutralized is provided at one end of the upper gas-liquid contact chamber 12 (the right end in FIGS. 1 and 2), and one end of the lower gas-liquid contact chamber 10 is provided. 1 (the right end in FIGS. 1 and 2) is provided with a discharge port 32 for discharging the neutralized alkaline drainage, and the other ends of the upper gas-liquid contact chamber 12 and the lower gas-liquid contact chamber 10 (FIG. 1). 2 and the left end side in FIG. 2 is provided with a communication pipe structure 34 for supplying alkaline drainage in the upper gas-liquid contact chamber 12 to the lower gas-liquid contact chamber 10.

  The illustrated communication tube structure 34 has a U-shaped tube portion 36 extending in a substantially U shape, and one end portion (right end portion in FIG. 2) of the U-shaped tube portion 36 communicates with the upper gas-liquid contact chamber 12. This one end defines an outlet 38. The other end portion of the U-shaped tube portion 36 has a slightly lower vertical height than one end portion, and the other end portion is connected to the lower air liquid via a connecting tube portion 40 that extends downward in a substantially L shape. The downstream end portion of the connecting pipe portion 40 communicates with the contact chamber 10 and defines an inflow port 42. The other end portion of the U-shaped tube portion 36 communicates with the upper gas-liquid contact chamber 12 via a gas vent tube portion 42 extending upward in a substantially L shape, and the upper end portion thereof defines a gas vent port 44. . In the upper gas-liquid contact chamber 12, the vertical position of the supply port 30 is set higher than the outlet 38 of the communication structure 34, and the vertical position of the gas vent 44 is set higher than the position of the supply port 30. ing. In the lower gas-liquid contact chamber 10, the vertical position of the inlet 42 is set higher than the outlet 32.

  Since it is configured in this way, the alkaline drainage supplied from the supply port 30 to the upper gas-liquid contact chamber 12 flows out from the outlet 38 to the downstream side, and the level of alkaline drainage in the upper gas-liquid contact chamber 12 is This is the position of the outlet 38. Further, the alkaline drainage fed to the downstream side through the communication mechanism 34 flows into the lower gas-liquid contact chamber 10 from the inlet 42, is discharged from the outlet 32, and the level of the alkaline drainage in the lower gas-liquid contact chamber 10. Is the position of the discharge port 32. In the communication mechanism 34, a part of the alkaline drainage flowing from the upper gas-liquid contact chamber 12 to the lower gas-liquid contact chamber 10 is collected in the U-shaped tube portion 36, and is separated from the alkaline drainage in the U-shaped tube portion 36. The gas (most of which is combustion exhaust gas) flows into the upper gas-liquid contact chamber 12 through the gas vent pipe portion 42. Further, the lower gas-liquid contact chamber 10 and the upper gas-liquid contact chamber 12 are communicated with each other via the connection pipe portion 40 and the gas vent pipe portion 42 of the communication mechanism 34. Keep the same pressure. In addition, since the gas vent 44 of the gas vent pipe portion 42 is arranged at a position higher than the supply port 30, the gas vent 44 is not immersed in the alkaline drainage, and the gas venting function and both gas-liquid contact chambers are provided. The pressure equalizing function of 10, 12 is always exhibited.

  The lower ventilation partition wall 26 and the upper ventilation partition wall 28 are provided with a number of ventilation slits 46 and 48, respectively. 4 and 5, the upper gas-liquid contact chamber 12 and the upper ventilation partition wall 28 and the lower gas-liquid contact chamber 10 and the lower ventilation partition wall 26 have substantially the same configuration. The contact chamber 12 and the upper ventilation partition wall 28 will be described. The upper gas-liquid contact chamber 12 (lower gas-liquid contact chamber 10) has an elongated rectangular shape, and its vertical direction (the flow direction of alkaline waste water, The ratio (W / L) of the dimension W in the width direction (the direction perpendicular to the paper surface in FIG. 2, the vertical direction in FIG. 5) to the dimension L in the left-right direction in FIG. 5 is 1/5 to 1/10 [ 1/5 ≦ (W / L) ≦ 1/10], and by setting the dimensional ratio (W / L) to such a range, the upper gas-liquid contact chamber 12 (lower gas-liquid contact chamber 10). The length of the alkaline drainage in the flow direction of the It is possible to increase the neutralizing efficiency in the neutralization process of predicates.

  The plurality of ventilation slits 48 (46) are provided at intervals in the longitudinal direction (alkaline drainage flow direction) of the upper ventilation partition wall 28 (lower ventilation partition wall 26). The slit 48 (46) is provided in a straight line from one end in the width direction to the other end of the upper ventilation partition wall 28 (lower ventilation partition wall 26). Each ventilation slit 48 (46) is provided so as to be inclined and extend in an oblique direction. By providing the ventilation slit 48 (46) in such an oblique direction, the combustion exhaust gas flowing through the ventilation slit 48 (46) becomes a small bubble and is It is fed to the alkaline waste water in the liquid contact chamber 12 (lower gas-liquid contact chamber 10), and the gas-liquid contact efficiency between the combustion exhaust gas and the alkaline waste water can be increased.

  As shown in FIG. 2, the plurality of ventilation slits 48 (46) are provided on one side (right side in FIGS. 2 and 5) of the ventilation slit 48 (46) with the central portion in the longitudinal direction as a boundary. Is inclined upward and extended to one side (right side in FIGS. 2 and 5), and the ventilation slit 48 (46) provided on the other side (left part in FIGS. 2 and 5) is directed upward. It is preferable to extend inclined to the other side (left side in FIGS. 2 and 5).

  The slit width S (see FIG. 4) of the plurality of ventilation slits 48 (46) is preferably set to 2 to 8 mm (2 mm ≦ S ≦ 8 mm). It can be neutralized well. When the slit width S is smaller than 2 mm, the passage linear velocity of the combustion exhaust gas through the ventilation slit 48 (46) increases, and there is a possibility that the alkaline drainage blows off. On the other hand, when the slit width S is larger than 8 mm, the combustion exhaust gas The passage linear velocity flowing through the ventilation slit 48 (46) becomes small, and there is a possibility that the alkaline drainage falls through the ventilation slit 48 (46).

  The total area S2 of the upper ventilation partition wall 28 (lower ventilation partition wall 26) of the upper gas-liquid contact chamber 12 (lower gas-liquid contact chamber 10), that is, the bottom surface of the upper gas-liquid contact chamber 12 (lower gas-liquid contact chamber 10). The ratio (S1 / S2) of the total slit area S1 of the plurality of ventilation slits 48 (46) formed therein to the area of the defined region is 1/70 to 1/30 [1/70 ≦ (S1 / S2 ) ≦ 1/30]. When this ratio (S1 / S2) is smaller than 1/70, although it is related to the slit width S of the ventilation slit 48 (46), the total opening area of the ventilation slit 48 (46) is small, and a desired amount of combustion exhaust gas is removed. If it is going to supply to alkaline drainage, the passage linear velocity of the combustion exhaust gas which flows through ventilation slit 48 (46) will become large, and there exists a possibility that alkaline drainage may blow off. On the other hand, if this ratio (S1 / S2) is greater than 1/30, it is related to the slit width S of the ventilation slit 48 (46), but the total opening area of the ventilation slit 48 (46) is large, and a predetermined amount of combustion occurs. If the exhaust gas is supplied to the alkaline drainage, the passage linear velocity of the combustion exhaust gas flowing through the ventilation slit 48 (46) decreases, and there is a possibility that the alkaline drainage falls through the ventilation slit 48 (46).

  The passage linear velocity V of the combustion exhaust gas flowing through the ventilation slit 48 (46) of the upper ventilation partition wall 28 (lower ventilation partition wall 26) is 6 to 20 m / second (6 m / second ≦ V ≦ 20 m / second). preferable. When the passage linear velocity of the combustion exhaust gas is smaller than 6 m / sec, it relates to the ratio (S1 / S2) of the slit width S of the ventilation slit 48 (46) and the total area S1 of the ventilation slit 48 (46). The pressure of the combustion exhaust gas flowing through the slit 48 (46) decreases, and there is a risk that the alkaline drainage will fall through the ventilation slit 48 (46). On the other hand, if the passage linear velocity of the combustion exhaust gas is larger than 20 m / sec, it is also related to the slit width S of the ventilation slit 48 (46) and the ratio (S1 / S2) regarding the total area S1 of the ventilation slit 48 (46). Further, the pressure of the combustion exhaust gas flowing through the ventilation slit 48 (46) increases, and there is a possibility that the alkaline drainage blows away.

  Alkaline drainage from the drainage tank 52 is supplied to the supply port 12 of the upper gas-liquid contact chamber 12 of the neutralization treatment tank 2. The drainage tank 52 and the upper gas-liquid contact chamber 12 of the neutralization processing tank 2 are connected via a drainage supply pipe 54, and a drainage supply pump 56 is disposed in the drainage supply pipe 54. Alkaline wastewater generated in a factory or the like is temporarily stored in the drainage tank 52, and the alkaline drainage in the drainage tank 52 is passed through the drainage supply pipe 54 to the upper gas-liquid contact chamber 12 by the suction / feeding action of the drainage supply pump 56. Supplied.

  To neutralize alkaline wastewater as required by gas-liquid contact with combustion exhaust gas, when using combustion exhaust gas containing 6 to 12% carbon dioxide, combustion exhaust per liter of alkaline wastewater is used. It is preferable to supply 150 to 500 liters of gas, and by supplying combustion exhaust gas having a gas-liquid ratio in such a range, the neutralization efficiency of the alkaline drainage is optimal.

  Further, when the neutralization treatment is performed at the above-described gas-liquid ratio, the amount of the alkaline drainage retained in the upper gas-liquid contact chamber 48 (lower gas-liquid contact chamber 46) is the height H (FIG. 4). Is preferably 150 to 250 mm in a stationary state (150 mm ≦ H ≦ 250 mm). By setting the amount of retained liquid in the above-described height range, the time for gas-liquid contact between the combustion exhaust gas and the alkaline drainage becomes appropriate, and the alkaline drainage can be neutralized efficiently.

  In this embodiment, as shown also in FIG. 3, the distal end side (one end side) of the exhaust gas supply pipe 22 extends into the exhaust gas chamber 8 through the lower housing 4 and then extends upward (one end portion). ) Is provided with an openable / closable flapper 62. The open / close flapper 62 is composed of a plate-like member, and one end of the open / close flapper 62 is pivotally attached to the exhaust gas supply pipe 22 via a connecting member 64 such as a hinge. When combustion exhaust gas from the gas engine 14 is not delivered, the open / close flapper 62 turns in the direction indicated by the arrow due to its own weight and hits one end surface of the exhaust gas delivery pipe 22 as shown by a two-dot chain line in FIG. Close the opening in contact. Therefore, even if alkaline drainage falls from the lower gas-liquid contact chamber 10 through the ventilation slit 46 of the lower ventilation partition wall 26, the fallen alkaline drainage can be prevented from flowing into the exhaust gas supply pipe 22. When combustion exhaust gas from the gas engine 14 is supplied, the open / close flapper 62 is swung upward by the supply pressure of the combustion exhaust gas flowing through the exhaust gas supply pipe 22, as shown by the solid line in FIG. One end opening of the exhaust gas feed pipe 22 is opened, and the combustion exhaust gas from the gas engine 14 is fed to the exhaust gas chamber 8 of the neutralization treatment tank 2 through the exhaust gas feed pipe 22. In addition, a gas discharge port 68 is provided in the upper wall 66 of the upper housing 6 and is fed from the exhaust gas chamber 8 to the upper gas-liquid contact chamber 12 through the lower gas-liquid contact chamber 10 as will be described later. The combustion exhaust gas is discharged to the outside through the gas discharge port 68 of the upper wall 66.

  Next, the neutralization process of the alkaline waste water by the neutralization apparatus mentioned above is demonstrated. When performing the neutralization process, the alkaline drainage accumulated in the drainage tank 52 is supplied to the upper gas-liquid contact chamber 12 by the drainage supply pump 56 through the drainage supply pipe 54. The alkaline drainage supplied in this way flows from one end side (right end side in FIG. 2) to the other end side (left end side in FIG. 2) of the upper gas-liquid contact chamber 12, and then the U-shape of the communication mechanism 34 It is fed to the lower gas-liquid contact chamber 10 through the pipe part 36 and the connecting pipe part 40. The alkaline drainage supplied to the lower gas-liquid contact chamber 10 in this way flows from the other end side (left end side in FIG. 2) of the lower gas-liquid contact chamber 10 to one end side (right end side in FIG. 2). It is discharged to the outside from the discharge port 32 provided in.

  When the neutralization process is performed, a part of the combustion exhaust gas from the gas engine 14 is sent to the exhaust gas chamber 8 of the neutralization tank 2 through the exhaust gas feed pipe 22 by the action of the feed blower 24. The combustion exhaust gas thus fed is fed to the lower gas-liquid contact chamber 10 through a number of ventilation slits 46 provided in the lower ventilation partition wall 26, and thereafter, a large number of the combustion exhaust gas provided in the upper ventilation partition wall 28. After being fed to the upper gas-liquid contact chamber 12 through the ventilation slit 48, it is discharged to the outside through a gas discharge port 68 provided in the upper wall 66.

  In the upper gas-liquid contact chamber 12, the alkaline exhaust water supplied from the drain tank 52 and the combustion exhaust gas fed in the form of bubbles through the ventilation slit 48 of the upper ventilation partition wall 28 (neutralized in the lower gas-liquid contact chamber 10). In contact with the gas and liquid, and neutralization of the alkaline drainage is performed using carbon dioxide contained in the combustion exhaust gas, and neutralization is performed in the upper gas-liquid contact chamber 12. Alkaline wastewater is fed to the lower gas-liquid contact chamber 10 through the communication structure 34. Further, in the lower gas-liquid contact chamber 10, the combustion exhaust gas (from the gas engine 14) supplied in the form of bubbles through the alkaline drainage supplied from the upper gas-liquid contact chamber 12 and the ventilation slit 46 of the lower ventilation partition wall 26. In this lower gas-liquid contact chamber 10, neutralization treatment of alkaline waste water is also performed using carbon dioxide in the combustion exhaust gas. At this time, alkaline waste water neutralized in the upper gas-liquid contact chamber 12 (neutralized to some extent and having a lowered pH value) is supplied to the lower gas-liquid contact chamber 8, while the exhaust gas chamber 8 The combustion exhaust gas (combustion exhaust gas having a high carbon dioxide content) is bubbled through the ventilation slit 46 and fed to the alkaline drainage, so that the combustion exhaust gas is sufficiently neutralized, Alkaline waste water that has been sufficiently neutralized is discharged from the drain port 32.

  In order to confirm the effect of the alkaline wastewater neutralizing apparatus described above, the following experiment was conducted as the first. The alkaline wastewater neutralization treatment apparatus having the form shown in FIGS. 1 to 5 was used, and the dimensions of the neutralization treatment tank were as follows. The vertical dimension L of the lower gas-liquid contact chamber and the upper gas-liquid contact chamber is 120 cm, and the width direction dimension W thereof is 20 cm. The height H (retained liquid amount) was 20 cm. The combustion exhaust gas of the gas engine was used for the neutralization treatment, and the carbon dioxide content of the combustion exhaust gas was about 6%, and 150 liters of combustion exhaust gas was sent per liter of alkaline waste water. Three types of lower ventilation partition walls and upper ventilation partition walls were used, and the results of neutralization treatment of alkaline wastewater (pH values before and after neutralization treatment) when using them were examined. The pH before the neutralization treatment was the pH value of the alkaline waste water supplied to the upper gas-liquid contact chamber, and the pH after the neutralization treatment was the pH value of the alkaline waste water discharged from the lower gas-liquid contact chamber.

この実験結果は、上記表１に示す通りであった。下通気仕切壁及び上通気仕切壁として通気仕切壁Ｂ（通過仕切壁の全面積Ｓ２に対する多数の通気スリットの全スリット面積Ｓ１の比率であるスリット面積比率（Ｓ１／Ｓ２）が０．０１９であるもの）を用いたときには、ｐＨ１２．９７のアルカリ性排水をｐＨ８．０１まで中和処理することができ、燃焼排気ガスを用いて充分に中和処理することができた。これに対して、通気仕切壁Ａを用いた場合、ｐＨ１３．０６のアルカリ性は汚水をｐＨ８．９９までしか中和処理することができず、また通気仕切壁Ｃを用いた場合、ｐＨ１３．０６のアルカリ性排水をｐＨ９．９０までしか中和処理することができず、通気仕切壁のスリット面積比率が過大になったり、過小になったりすると、中和処理が充分に行うことができなかった。

The experimental results were as shown in Table 1 above. A ventilation partition wall B as a lower ventilation partition wall and an upper ventilation partition wall (slit area ratio (S1 / S2) which is a ratio of the total slit area S1 of a large number of ventilation slits to the total area S2 of the passage partition wall is 0.019) In this case, alkaline wastewater having a pH of 12.97 could be neutralized to pH 8.01, and sufficiently neutralized using combustion exhaust gas. On the other hand, when the ventilation partition wall A is used, the alkalinity of pH 13.06 can neutralize sewage only to pH 8.99, and when the ventilation partition wall C is used, the pH of 13.06 The alkaline wastewater could only be neutralized up to pH 9.90, and if the slit area ratio of the ventilation partition wall was excessive or too small, the neutralization could not be performed sufficiently.

  The second experiment was conducted as the second. The alkaline wastewater neutralization treatment apparatus similar to the first experiment described above was used, and the dimensions of the lower gas liquid contact chamber and the upper gas liquid contact chamber of the neutralization tank were the same. In the second experiment, 150 liters of combustion exhaust gas was supplied per liter of alkaline waste water. Three types of lower ventilation partition walls and upper ventilation partition walls are used, and the results of neutralization treatment of alkaline wastewater (pH values before and after neutralization treatment) when using them are the same as described above. I investigated.

この実験結果は、上記表２に示す通りであった。下通気仕切壁及び上通気仕切壁として通気仕切壁Ｅ及びＦ（スリット幅Ｓが２ｍｍと４ｍｍのもの）を用いたときには、それぞれ、ｐＨ１３．２９、ｐＨ１３．２０のアルカリ性排水をｐＨ８．６２、ｐＨ８．６９まで中和処理することができた。これに対して、通気仕切壁Ｄを用いた場合、ｐＨ１３．２５のアルカリ性排水をｐＨ９．８８までしか中和処理することができず、通気スリットのスリット幅が過小になると中和処理が充分に行うことができなかった。

The experimental results were as shown in Table 2 above. When the ventilation partition walls E and F (with slit width S of 2 mm and 4 mm) are used as the lower ventilation partition wall and the upper ventilation partition wall, alkaline drainage of pH 13.29 and pH 13.20 are pH 8.62 and pH 8 respectively. .69 could be neutralized. On the other hand, when the ventilation partition wall D is used, it is possible to neutralize alkaline drainage having a pH of 13.25 only up to pH 9.88. If the slit width of the ventilation slit is too small, the neutralization treatment is sufficiently performed. Could not do.

  As the third experiment, the following experiment was conducted. Using the same alkaline wastewater neutralization treatment apparatus as in the first experiment described above, the dimensions of the lower gas liquid contact chamber and upper gas liquid contact chamber of the neutralization tank are the same, and the slit of the ventilation slit of the ventilation partition wall The width was 2 mm and the slit area ratio (S1 / S2) was 0.019. In the third experiment, the amount of combustion exhaust gas delivered per liter of alkaline wastewater, that is, the result of neutralization treatment of alkaline wastewater when the gas-liquid ratio was changed (pH values before and after neutralization treatment) ) Was examined as described above.

この実験結果は、上記表３に示す通りであった。中和条件Ｉの場合、ｐＨ１３．１４のアルカリ性排水をｐＨ７．９５まで中和処理することができた。これに対して、中和条件Ｇ，Ｈの場合、それぞれ、ｐＨ１３．０６、ｐＨ１２．０６のアルカリ性排水をｐＨ８．９８、ｐＨ８．８１までしか中和処理することができず、気液比率が過小になる（アルカリ性排水の量に対して燃焼排気ガスの送給量が少なくなる）と中和処理が充分に行うことができなかった。

The experimental results were as shown in Table 3 above. In the case of neutralization condition I, it was possible to neutralize alkaline drainage having a pH of 13.14 up to pH 7.95. On the other hand, in the case of neutralization conditions G and H, it is possible to neutralize alkaline drainage at pH 13.06 and pH 12.06 only to pH 8.98 and pH 8.81, respectively, and the gas-liquid ratio is too small. (Neutralization treatment could not be carried out sufficiently).

  As mentioned above, although one Embodiment of the alkaline waste water neutralization processing apparatus according to this invention was described, this invention is not limited to this Embodiment, Various deformation | transformation thru | or correction | amendment are possible, without deviating from the scope of the present invention. It is.

  For example, in the above-described embodiment, the gas-liquid contact chambers 10 and 12 are described as being applied in two stages in the vertical direction. However, the present invention is not limited to such a form. The present invention can also be applied to those arranged in three or more stages in the direction. In this case, the communication structure 34 described above is arranged between a pair of gas-liquid contact chambers adjacent in the vertical direction.

  In this alkaline wastewater neutralization treatment apparatus, it is possible to neutralize alkaline wastewater using combustion exhaust gas by bringing the combustion exhaust gas from a gas engine or the like into contact with the alkaline wastewater to be neutralized in a bubble state. . In addition, since the alkaline waste water is neutralized using the combustion exhaust gas, the running cost is low, and the amount of carbon dioxide that causes global warming can be reduced. Such an alkaline wastewater neutralization treatment apparatus can be suitably applied to neutralization treatment of alkaline wastewater discharged from a factory or the like, and the equipment cost and power cost can be reduced.

It is a simplification figure showing simply one embodiment of the alkaline drainage neutralization processing device according to the present invention. It is sectional drawing which shows the neutralization processing tank of the neutralization processing apparatus of FIG. It is a fragmentary sectional view which shows the one end part of the exhaust gas supply pipe | tube of the neutralization processing tank of FIG. It is sectional drawing which shows a part of ventilation partition wall of the neutralization processing tank of FIG. 2, and its vicinity. It is sectional drawing which looked at the upper gas-liquid contact chamber of the neutralization processing tank of FIG. 2 from the upper side.

Explanation of symbols

2 Neutralization processing tank 8 Exhaust gas chamber 10, 12 Gas-liquid contact chamber 14 Gas engine 20 Exhaust gas supply means 22 Exhaust gas supply pipe 26, 28 Ventilation partition wall 30 Supply port 32 Discharge port 34 Communication structure 36 U-shape Pipe part 40 Connection pipe part 42 Gas vent pipe part 46, 48 Ventilation slit 52 Drainage tank 62 Opening / closing flapper

Claims (5)

A drainage tank for storing alkaline drainage, a neutralization tank for neutralizing alkaline drainage, and an exhaust gas supply means for supplying combustion exhaust gas to the neutralization tank; An alkaline wastewater neutralization treatment apparatus that feeds the wastewater from the neutralization treatment tank and neutralizes the exhaust gas from the exhaust gas feeding means in contact with the alkaline wastewater in the neutralization treatment tank. There,
The neutralization treatment tank includes an exhaust gas chamber into which combustion exhaust gas from the exhaust gas supply unit flows, and a gas-liquid contact chamber into which alkaline drainage from the drain tank flows, and the exhaust gas chamber and the A ventilation partition wall is provided between the gas-liquid contact chamber, a plurality of ventilation slits extending in an oblique direction are provided in the ventilation partition wall, and combustion exhaust gas from the exhaust gas chamber is supplied to the plurality of ventilation gas. An alkaline wastewater neutralizing apparatus characterized by being fed into the gas-liquid contact chamber through a slit in the form of bubbles. The gas-liquid contact chamber of the neutralization treatment tank is composed of a lower gas-liquid contact chamber disposed above the exhaust gas chamber and an upper gas-liquid contact chamber disposed above the lower gas-liquid contact chamber. A lower ventilation partition wall is provided between the exhaust gas chamber and the lower gas-liquid contact chamber, and an upper ventilation partition wall is provided between the lower gas-liquid contact chamber and the upper gas-liquid contact chamber, The lower ventilation partition wall and the upper ventilation partition wall are provided with a plurality of ventilation slits extending in an oblique direction, alkaline drainage flows from the upper gas-liquid contact chamber through the lower gas-liquid contact chamber, and combustion exhaust gas is 2. The alkaline wastewater neutralization apparatus according to claim 1 , wherein the exhaust gas chamber flows from the exhaust gas chamber through the lower gas-liquid contact chamber to the upper gas-liquid contact chamber.   The lower gas-liquid contact chamber and the upper gas-liquid contact chamber are communicated with each other by a communication pipe structure, and the communication pipe structure has a U-shaped tube portion for collecting drainage, and one end portion of the U-shaped tube portion is A gas vent pipe that communicates with the upper gas-liquid contact chamber and communicates with the lower gas-liquid contact chamber via a connecting pipe portion whose other end extends downward, and the other end of the U-shaped tube portion extends upward. The alkaline wastewater neutralizing apparatus according to claim 2, wherein the apparatus is in communication with the upper gas-liquid contact chamber through a section.   The ratio (S1 / S2) of the slit area S1 of the plurality of ventilation slits to the area S2 of the ventilation partition wall is 1/70 to 1/30, and the passage of the combustion exhaust gas passing through the plurality of ventilation slits The linear wastewater neutralization treatment apparatus according to any one of claims 1 to 3, wherein the linear velocity is 6 to 20 m / sec. The exhaust gas supply means includes an exhaust gas supply pipe for guiding the exhaust gas to the exhaust gas chamber of the neutralization treatment tank, and one end of the exhaust gas supply pipe extends into the exhaust gas chamber, An open / close flapper is provided at one end so as to be openable and closable. When combustion exhaust gas is supplied from the exhaust gas supply means to the exhaust gas chamber, the open / close flapper is controlled by the supply pressure of the combustion exhaust gas. The open / close flapper is maintained in the closed state by the dead weight of the open / close flapper when the combustion exhaust gas supply from the exhaust gas supply means is stopped. The alkaline wastewater neutralization treatment apparatus according to any one of 1 to 4.

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