JP2014050820A - Decarboxylation processing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy saving-type decarboxylation processing unit which can reduce an electric power cost required for supplying with treated water that free carbon dioxide component is removed.SOLUTION: A decarboxylation processing unit 10 comprises: a tank unit 20 being supplied water to treat 31 and air 61 for decarboxylation; an exhaust outlet 50 disposed on a top part of the tank unit and releasing exhaust gas 51 outside the tank unit; a treated water outflow unit 80 containing a pipe 82 communicating to a treated water storage unit 70 which is lower part of the tank unit and rising up to a position which is higher than the treated water storage unit, and supplying with the treated water to a treated water tank 90 (devices using the treated water); and a displacement volume control unit 100 controlling displacement volume of exhaust gas in the exhaust outlet. The decarboxylation processing unit controls the displacement volume in the exhaust outlet 50 by the displacement volume control unit, holds a treated water level 72 in the treated water storage unit in a water level set in advance, and supplies with the treated water only by differential pressure of the pressure in the tank unit and the pressure in the treated water tank through the treated water outflow unit.

Description

  The present invention relates to a decarboxylation apparatus that removes free carbonic acid components from water to be treated, and more particularly to an energy-saving decarboxylation apparatus that has a simple structure and does not require a water pump.

When well water is used as a water source, there is generally more free carbonic acid than river water. For this reason, troubles in which the piping is clogged with the scale or the piping is corroded easily occur. The form of carbonic acid in such well water varies depending on the pH, but most of the free carbonic acid exists in the state of CO ₂ gas, and part of it exists in the form of molecular carbonic acid (H ₂ CO ₃ ). doing. The well water contains dissociated bicarbonate ions (HCO ₃ ⁻ ) and carbonate ions (CO ₃ ²⁻ ) in addition to free carbonic acid.

  For example, as shown in the following formula (1), the remaining free carbonic acid excluding the dependent free carbonic acid necessary for dissolving the bicarbonate in water becomes so-called erodible free carbonic acid. Erosive free carbonic acid causes corrosion of piping and the like. On the contrary, if there is little dependent free carbonic acid, Formula (1) will move to the left side, and for this reason, calcium carbonate will precipitate and a scale will be formed.

  In addition, when pure water is produced with an ion exchange treatment device in the pure water production process, not only free carbonic acid but also bicarbonate ions and carbonate ions become an ionic load on the anion exchange resin, causing a reduction in the treatment capacity of the anion exchange resin. It becomes. Alternatively, in the RO treatment apparatus, free carbonic acid that has not been dissociated by the RO membrane cannot be removed, so that free carbonic acid leaks into the RO treated water, which deteriorates the water quality such as the conductivity of the treated water.

  As described above, free carbonic acid corrodes piping and clogs by forming a scale, and further causes the performance of the pure water production apparatus to deteriorate in the pure water production process. Therefore, generally, free carbonic acid is removed by a decarboxylation tower.

  For example, Patent Document 1 discloses an invention relating to a deoxygenation and decarboxylation apparatus and a treatment method. The nitrogen deaeration tower disclosed in the publication has the same structure as that of a so-called conventional decarboxylation tower, and in the conventional decarboxylation tower, a function of deoxygenation is added by changing air to nitrogen. . That is, the pH of the water to be treated introduced into the nitrogen deaeration tower (decarbonation tower) is adjusted to 6.5 or less by adding acid in advance, and the water to be treated adjusted to acidity is supplied from the upper part of the packed bed. To do. Nitrogen is spouted from a nitrogen aeration nozzle arranged in the lower part of the packed bed, and nitrogen and treated water are brought into contact with each other in the packed bed to remove oxygen and free carbonic acid. A technique is described in which alkali is added to the treated water to adjust the pH to 6.5 to 9, and then the treated water is discharged by a water pump. The reason for adjusting the pH of the decarboxylated water to be neutral or higher is that the pH of the water to be treated is adjusted in advance to be acidic. This may cause corrosion.

  As disclosed in Patent Document 1, a conventional decarboxylation tower generally uses a filler and feeds treated water to the next process by a water pump.

JP 2003-47950 A

  A conventional decarbonation tower uses a filler, supplies water to be treated from the upper part of the packed bed, blows out air from an aeration nozzle disposed at the lower part of the packed bed, and air and treated water in the packed bed. Free carbonic acid is removed by contact. For this reason, in the conventional decarboxylation tower, in order to lower the carbon dioxide partial pressure of the packed bed, it is necessary to sufficiently exhaust from the top of the tower. As a result, it is difficult to form a sealed structure or pressurize and decarboxylate. Therefore, in order to transfer treated water to the next process, it is indispensable to use a water pump.

  By the way, in recent society where energy saving is strongly demanded, reduction of electric power cost is an issue. However, since the conventional decarboxylation tower requires a pump for sending treated water to the next process, it is difficult to reduce the power cost.

  The present invention has been made paying attention to such problems of the conventional technology, and is an energy-saving type that can reduce the power cost required to feed treated water from which free carbonic acid components have been removed. An object is to provide a decarboxylation apparatus.

  The object of the present invention is achieved by the following means.

(1) A decarboxylation device for removing free carbonic acid components from water to be treated,
A tank unit to which water to be treated and air for decarboxylation are supplied;
A treated water introduction pipe connected to the upper part of the tank section for introducing the treated water;
A nozzle part that is provided at an end of the treated water introduction pipe and injects the treated water into the tank part;
An acid introduction pipe connected to the treated water introduction pipe for adding an acid for adjusting the pH of the treated water;
An exhaust part disposed at the top of the tank part for discharging exhaust gas to the outside of the tank part;
An air introduction pipe connected to the lower part of the tank part for introducing the air;
An air supply unit provided at an end of the air introduction pipe to supply the air into the tank unit;
A treated water storage section for storing treated water from which free carbonic acid components have been removed, disposed at the bottom of the tank section;
A treated water outflow section that includes a conduit that communicates with the treated water storage section and rises to a position higher than the treated water storage section, and that feeds the treated water to a device that uses the treated water;
An exhaust amount control unit for controlling an exhaust amount of exhaust gas discharged to the outside of the tank unit in the exhaust unit,
In an apparatus that uses the pressure in the tank and the treated water to maintain the treated water level in the treated water storage unit at a predetermined water level by controlling the exhaust amount in the exhaust unit by the exhaust amount control unit. A decarboxylation apparatus in which the treated water is fed through the treated water outflow portion only by a pressure difference from the pressure.

(2) The displacement control unit
A detection unit for detecting a treated water level in the treated water storage unit;
An electrically driven valve disposed in the exhaust part, the electrically driven valve having an opening degree of the valve body adjusted in conjunction with the treated water level detected by the detecting part ( The decarboxylation apparatus as described in 1).

(3) It further has a water level measurement unit that communicates with the tank unit at a position above the treated water level in the treated water storage unit and a position below the treated water level in the treated water storage unit,
The said detection part is a decarboxylation processing apparatus as described in said (2) which detects the treated water level in the said treated water storage part by detecting the treated water level in the said water level measurement part.

(4) The displacement control unit
A mechanically driven valve disposed in the exhaust part, comprising a mechanism capable of setting a force for biasing the valve body in the closing direction, and the opening degree of the valve body is adjusted in conjunction with the pressure in the tank part. The decarboxylation apparatus according to (1), which has a mechanically driven valve.

  (5) Any of (1) to (4), wherein the air supply unit is immersed in the treated water stored in the treated water storage unit and diffuses the air into the treated water. The decarboxylation apparatus as described in any one.

  According to the decarbonation apparatus of (1) above, the exhaust amount control unit controls the exhaust amount in the exhaust unit to maintain the treated water level in the treated water storage unit at a predetermined water level, The treated water is sent through the treated water outflow part only by the pressure difference with the pressure in the equipment or the like using the treated water. Since the pump for feeding the treated water is not used, it is possible to reduce the power cost required to feed the treated water from which the free carbonic acid component has been removed, and an energy-saving decarboxylation treatment apparatus can be provided.

  According to the decarboxylation processing apparatus of (2) above, the displacement control unit includes an electrically driven valve in which the opening of the valve body is adjusted in conjunction with the treated water level detected by the detection unit. As the treated water level drops, the opening of the electrically driven valve is increased to lower the internal pressure of the tank, and conversely, as the treated water level rises, the opening of the electrically driven valve is reduced to increase the internal pressure. By controlling in this way, it becomes possible to keep the internal pressure in a constant pressure state.

  According to the decarboxylation device of (3) above, hunting of the detection unit due to waving of the water surface can be prevented by detecting the treated water level in the water level measurement unit by the detection unit. Since the detection of the treated water level in the treated water storage unit is stabilized, the operation of the electrically driven valve in which the opening degree of the valve body is adjusted in conjunction with the treated water level is also stabilized. As a result, it is possible to control the optimum exhaust amount that keeps the treated water level constant.

  According to the decarboxylation device of (4) above, the exhaust amount control unit includes a mechanism that can freely set the force for urging the valve body in the closing direction, and the opening degree of the valve body in conjunction with the pressure in the tank unit. As the internal pressure of the tank part increases, the treated water level drops, but at this time, the valve body of the mechanical drive valve is pushed up by the internal pressure and the exhaust amount increases. . On the contrary, when the internal pressure becomes low, the valve body of the mechanically driven valve operates in the closing direction and is not released until the internal pressure increases. In this way, it becomes possible to maintain the internal pressure in a constant pressure state mechanically.

  According to the decarboxylation processing apparatus of (5) above, since the air supply unit diffuses air into the treated water, it is possible to further remove the free carbonic acid remaining slightly in the treated water. It becomes possible to improve the removal efficiency of a carbonic acid component.

1 is a basic system diagram showing a decarboxylation apparatus according to an embodiment of the present invention. It is a figure which shows pH and the theoretical ratio of a carbonic acid component. It is a systematic diagram which shows the decarboxylation processing apparatus to which the displacement control part which has an electrically driven valve is applied. It is sectional drawing which shows the swing type non-return valve applied to the displacement control part which has a mechanical drive valve. It is a graph which shows the relationship between the internal pressure of the tank part in a decarboxylation processing apparatus, and gas flow ratio. It is a systematic diagram which shows the form which further provided the water level measurement part in the decarboxylation processing apparatus to which the displacement control part using an electrically driven valve was applied. FIG. 7A is a system diagram showing a decarboxylation apparatus in which a nozzle part for injecting water to be treated is arranged upward, and FIG. 7B is a schematic view of a decarbonation apparatus in which a nozzle part for injecting water to be treated is arranged downward. It is a systematic diagram which shows a carbonic acid treatment apparatus. It is a graph which shows the influence which the direction of a nozzle part has on the removal rate of free carbonic acid. It is a graph which shows the influence which the ratio of the air quantity and the amount of to-be-processed water has on the removal rate of free carbonic acid. It is a graph which shows the relationship between pH of to-be-processed water and pH of treated water. 1 is a system diagram showing a decarbonation apparatus used in Example 1. FIG. 6 is a graph showing the processing performance of Example 1 and Comparative Example 1. FIG. 13 (A) is a system diagram showing the decarboxylation device used in Example 2, and FIG. 13 (B) is a system diagram showing the decarboxylation device used in Comparative Example 2.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The dimensional ratios in the drawings are exaggerated for convenience of explanation, and are different from the actual ratios.

  With reference to FIG. 1, the decarboxylation apparatus 10 according to the embodiment is generally used to remove free carbonic acid components from the water of the water to be treated 31, and the water to be treated 31 and the air for decarboxylation. The tank part 20 to which 61 is supplied is provided. In the upper region of the tank unit 20, the decarbonation apparatus 10 is provided at the end of the treated water introduction pipe 30 and the treated water introduction pipe 30 that is connected to the upper part of the tank unit 20 and introduces the treated water 31. An acid nozzle for adding an acid 41 for adjusting the pH of the water to be treated 31 connected to the water to be treated introduction pipe 30 and an injection nozzle 32 (equivalent to the nozzle part) for injecting the water to be treated 31 into the tank 20 It has a pipe 40 and an exhaust part 50 that is disposed at the top that is the uppermost part of the tank part 20 and discharges the exhaust gas 51 to the outside of the tank part 20. In the lower region of the tank unit 20, the decarbonation treatment apparatus 10 is connected to the lower part of the tank unit 20 and introduces air 61, and is provided at an end of the air introduction tube 60. A diffuser pipe 62 (corresponding to an air supply unit) that supplies air 61, and a treated water storage unit 70 that stores the treated water 71 that is disposed below the tank unit 20 and from which free carbonic acid components have been removed. Yes. The decarbonation treatment apparatus 10 further includes a conduit 82 that communicates with the treated water storage unit 70 and rises to a position higher than the treated water storage unit 70, and supplies the treated water 71 to equipment 90 that uses the treated water 71. A water outflow unit 80 and an exhaust amount control unit 100 that controls the exhaust amount of the exhaust gas 51 discharged to the outside of the tank unit 20 in the exhaust unit 50 are provided. Then, the decarbonation apparatus 10 controls the exhaust amount in the exhaust unit 50 by the exhaust amount control unit 100 to maintain the treated water level 72 in the treated water storage unit 70 at a predetermined water level. The treated water 71 is fed through the treated water outflow part 80 only by the differential pressure between the pressure and the pressure in the treated water tank 90 (corresponding to “equipment etc. using the treated water 71”). In the illustrated embodiment, the air diffuser 62 is immersed in the treated water 71 stored in the treated water reservoir 70 and diffuses the air 61 into the treated water 71. Hereinafter, the decarboxylation apparatus 10 according to the embodiment will be described in detail.

  In the decarboxylation apparatus 10, the pH of the water to be treated 31 is adjusted to be acidic before the water to be treated 31 flows into the tank unit 20. The means is made by adding a predetermined amount of acid 41 using a metering pump or the like through an acid introduction pipe 40 connected to the treated water introduction pipe 30 of the treated water 31.

  The acid to be used is inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, or organic acid such as citric acid, oxalic acid, formic acid, acetic acid, and other organic acids are generally carboxylic acid and sulfonic acid. Can be used.

  As shown in FIG. 2, by setting the pH of the water to be treated 31 to 4 or less, almost 100% of the carbonic acid component including bicarbonate ions and carbonate ions in the water to be treated 31 can be converted into free carbonic acid. . Moreover, 80% of the carbonic acid component can be converted into free carbonic acid by adjusting the pH of the water to be treated 31 to 5.7 or lower. By adjusting at least the pH of the water to be treated 31 to 6 or less, 70% of the carbonic acid component can be converted to free carbonic acid, and the decarbonation apparatus 10 can remove 70% of the free carbonic acid. .

  In the decarbonation processing apparatus 10, the pressurized air 61 discharged from the diffuser pipe 62 through the air introduction pipe 60 and the water to be treated 31 sprayed from the spray nozzle 32 are brought into countercurrent contact to remove free carbonic acid. To do. Furthermore, the injected water droplets collide with the inner wall of the tank unit 20 to wet the wall surface, and free carbonic acid is removed by a so-called wet wall effect that flows down along the inner wall. Next, the treated water 71 that has flowed down is introduced into the lower treated water reservoir 70, and the pressurized air 61 is pumped to the air diffuser 62 disposed below the treated water level 72 in the treated water reservoir 70. The treated water 71 is aerated by the pressurized air 61 released from the air diffuser 62. Since the free carbonic acid remaining slightly in the treated water 71 can be further removed, the efficiency of removing the free carbonic acid component is increased.

  The treated water 31 with adjusted pH is sprayed from the spray nozzle 32 toward the inner wall of the tank unit 20 through the treated water introduction pipe 30. Regarding the point of using the injection nozzle 32, there is description in JP-A-11-31803.

  The patent publication is a patent relating to a deaeration device. The deaeration device described in the above-mentioned patent publication has the same structure as that of the conventional decarboxylation device. In the conventional decarboxylation device, the air is changed to a gas for degassing nitrogen or the like. Deaeration function is added. That is, a gas disperser is installed below the packed bed containing the packing material, and an exhaust pipe and a water supply pipe for introducing the water to be treated are arranged at the top of the tower, and a spray nozzle connected to the water supply pipe The spraying of the water to be treated on the packed bed surface is described. The exhaust pipe described in the patent publication is merely for exhausting gas and does not have a function of adjusting or controlling the exhaust amount.

  On the other hand, the decarbonation processing apparatus 10 of this embodiment includes an exhaust amount control unit 100 that controls the exhaust amount, and is greatly different from the technique described in the above-mentioned patent publication.

  The conventional decarboxylation tower uses a water pump to feed decarboxylated treated water to a separately installed treated water tank.

  On the other hand, the decarbonation apparatus 10 of the present embodiment has an exhaust amount control unit 100 that controls the exhaust amount of the exhaust gas 51 discharged to the outside of the tank unit 20 in the exhaust unit 50. The exhaust amount control unit 100 controls the exhaust amount in the exhaust unit 50 to maintain the treated water level 72 in the treated water storage unit 70 at a predetermined water level, the pressure in the tank unit 20 and the pressure in the treated water tank 90. The treated water 71 can be fed through the treated water outflow part 80 only by the differential pressure of The retention of the treated water level 72 in the treated water storage unit 70 is only required to be within a range of plus or minus 20% of the target treated water level 72.

  In order to pressurize and maintain the internal pressure of the decarbonation treatment apparatus 10, the conduit 82 of the treated water outlet 80 connected to the treated water reservoir 70 is raised to a predetermined height, that is, the level of the full water level of the treated water tank 90. The amount of air introduced from the air introduction pipe 60 and the amount of exhaust from the exhaust unit 50 provided at the upper portion are controlled to maintain the internal pressure of the decarbonation processing apparatus 10 in a pressurized state. As a result, water can be supplied to the treated water tank 90. In this manner, the treated water 71 can be fed using the head of the supply pump of the treated water 31 without using the water pump.

  In the decarbonation processing apparatus 10 of the present embodiment, since a water pump is not used, it is possible to reduce the power cost required to feed the treated water 71 from which free carbonic acid components have been removed. A carbonic acid treatment apparatus 10 can be provided.

  In a conventional decarboxylation apparatus using a filler, since the filler has a complicated structure, fine impurities such as fine particles are deposited on the surface of the filler, and contamination easily proceeds. It is difficult to avoid bacterial growth, and slime may be generated in the packed bed. In the decarboxylation apparatus 10 of the present embodiment, since no filler is used, generation of slime due to bacterial propagation can be suppressed.

  The exhaust amount control unit 100 shown in FIG. 1 has a flow rate adjustment valve 101 that can manually adjust the opening degree of the valve body. When fluctuations in the amount of treated water introduced into the tank unit 20, the amount of introduced air, and the amount of treated water fed from the tank unit 20 are small, the flow rate adjusting valve 101 is manually adjusted to store the treated water. The treated water level 72 in the unit 70 can be maintained at a predetermined water level.

  On the other hand, the amount of treated water introduced into the tank unit 20, the amount of air introduced, or the amount of treated water fed from the tank unit 20 fluctuates, and the variation of the treated water level 72 in the treated water storage unit 70 is compared. If the target is large, the displacement control unit 100 can be configured as follows.

  FIG. 3 shows a decarbonation processing apparatus 10 to which an exhaust amount control unit 100 having an electrically driven valve 102 is applied. The exhaust amount control unit 100 shown in FIG. 3 includes a detection unit 103 that detects the treated water level 72 in the treated water storage unit 70 and an electrically driven valve 102 that is disposed in the exhaust unit 50. And an electrically driven valve 102 whose opening degree is adjusted in conjunction with the detected treated water level 72. For example, a level control meter that detects the treated water level 72 of the treated water storage unit 70 and outputs a control signal can be applied to the detection unit 103. For example, an electrically driven exhaust valve can be applied to the electrically driven valve 102. When an electromagnetic valve that performs only an opening / closing operation is used, the exhaust amount of the exhaust gas 51 can be controlled by changing the duty ratio of the opening time of the electromagnetic valve.

  The amount of air introduced from the air introduction pipe 60 and the amount of exhaust from the exhaust section 50 are controlled by controlling the opening degree of the electric exhaust valve 102 using the water level output signal of the level controller 103. be able to. More specifically, as the treated water level 72 is lowered, the opening of the electric exhaust valve 102 is increased to lower the internal pressure of the tank unit 20. Conversely, as the treated water level 72 is raised, the electric exhaust valve 102 If control is performed to increase the internal pressure by reducing the opening, the internal pressure can be maintained in a constant pressure state.

  FIG. 4 shows a swing type check valve applied to the displacement control unit 100 having the mechanical drive valve 110. The exhaust amount control unit 100 shown in FIG. 4 is a mechanically driven valve 110 disposed in the exhaust unit 50, and includes a mechanism 112 that can freely set a force for urging the valve body 111 in the closing direction. 20 has a mechanically driven valve 110 in which the opening degree of the valve body 111 is adjusted in conjunction with the pressure in the valve 20. A swing type check valve including a counterweight 114 can be applied to the mechanically driven valve 110. The swing type check valve 110 is a mechanism 112 capable of setting a force for biasing the valve body 111 in the closing direction, and a lever 113 attached coaxially to the rotation shaft of the valve body 111 and a fixing position with respect to the lever 113 can be adjusted. Counter weight 114. By adjusting the fixing position of the counter weight 114 with respect to the lever 113, the force for biasing the valve body 111 in the closing direction can be set.

  The internal pressure can be mechanically controlled by using the swing type check valve 110. More specifically, when the internal pressure of the tank unit 20 is increased, the treated water level 72 is lowered. At this time, the valve body 111 of the swing type check valve 110 is pushed up by the internal pressure, and the exhaust amount is increased. On the contrary, when the internal pressure becomes low, the valve element 111 of the swing type check valve 110 operates in a direction to be closed by the counter weight 114 and is not released until the internal pressure increases. The operation of the valve body 111 can be adjusted by the weight of the counter weight 114 and the fixed position with respect to the lever 113, and it is possible to control the optimum exhaust amount for making the treated water level 72 constant.

  Here, the use of a check valve as the exhaust valve is described in JP-A-62-74413. In the technology described in the patent publication, pressurized air or an inert gas is introduced into water to be treated by an injection device, and this gas / water mixture is sprayed from a spray device of a degassing device. Drain out of device through conduit and check valve. Further, the degassed water is introduced into the demineralizer through the collection tank. There is no description that the check valve has a function of controlling the internal pressure. Therefore, the technology described in the above-mentioned patent gazette is that (1) the pressurized air or the inert gas is mixed with the water to be treated before introducing the water to be treated into the treatment device, and (2) the check valve has an internal pressure. There is a clear difference from the decarboxylation apparatus 10 of the present embodiment in that it does not have the function of controlling.

  The relationship between the volume of the pressure vessel and the pressure of the filling gas is as follows.

  For example, when gas is sealed in a pressure vessel, the volume of the sealed gas is obtained by the following equation (2) from the relationship between the volume of the pressure vessel and the pressure that must be sealed.

V2 = V1 × (P2 / P1) × (K2 / K1) (2)
Here, the volume of the enclosed gas; V2
Volume of pressure vessel; V1
Filled gas pressure; P2
Atmospheric pressure; P1
Absolute temperature after sealing; K2
Absolute temperature before sealing; K1
It is.

  In the actual decarbonation apparatus 10, the internal pressure is maintained by a dynamic balance between the inflow amount of the pressurized air 61 and the exhaust amount from the exhaust unit 50. That is, if the inflowing air amount is Q1 and the exhausted air amount is Q2, the gas flow rate ratio Q1 / Q2 is equal to the gas volume ratio V2 / V1, and P2 and Q1 / Q2 are obtained from the equation (2). A relationship can be sought. The result is shown in FIG.

  The gas volume ratio can be obtained with respect to the internal pressure set from FIG. 5, and Q2 can be controlled by measuring Q1. For example, in order to set the internal pressure of the apparatus to 0.03 MPa, Q1 / Q2 may be adjusted to 1.3, and the gas flow rate ratio may be determined in accordance with an arbitrary internal pressure.

  The control of the gas flow rate ratio is to control the exhaust amount, and is nothing but adjusting the opening of the variable exhaust valve. At this time, a dynamic balance between the air inflow amount and the exhaust amount is established, and the treated water level 72 can maintain a constant level. After all, if the treated water level 72 is adjusted and maintained at a constant level, it is not necessary to obtain the gas flow rate ratio, and the opening degree of the exhaust valve may be simply controlled so that the treated water level 72 becomes constant. .

  As described above, the internal pressure control of the decarbonation treatment apparatus 10, that is, the control of the exhaust amount may be performed electrically or mechanically as long as the treated water level 72 can be kept constant at a certain level. For example, if the internal pressure of the decarboxylation apparatus 10 is 30 kPa, water can be supplied to the treated water tank 90 having a height of about 3 m, and if the internal pressure is 50 kPa, water can be supplied to the treated water tank 90 having a height of about 5 m. .

  In the decarbonation treatment apparatus 10, the pressurized air 61 is discharged from the diffuser pipe 62 to aerate the treated water 71, so that the surface of the treated water 71 undulates and the signal of the level controller 103 hunts to control the exhaust amount. May be difficult. In such a case, the decarboxylation apparatus 10 may be configured as follows.

  FIG. 6 shows a form in which a water level measuring unit 120 is further provided in the decarbonation processing apparatus 10 to which the displacement control unit 100 using the electrically driven valve 102 is applied. In addition to the configuration of the decarbonation processing apparatus 10 illustrated in FIG. 3, the decarbonation processing apparatus 10 illustrated in FIG. 6 includes a position above the treated water level 72 in the treated water storage unit 70 and the treated water storage unit 70. And a water level measuring unit 120 communicating with the tank unit 20 at a position below the treated water level 72. The detection unit 103 detects the treated water level 72 in the treated water storage unit 70 by detecting the treated water level 122 in the water level measuring unit 120. The water level measuring unit 120 communicates with the tank unit 20 at a position above the treated water level 72 in the treated water storage unit 70 via the upper communication pipe 123. The water level measuring unit 120 communicates with the tank unit 20 at a position below the treated water level 72 in the treated water storage unit 70 via the lower communication pipe 124. By attaching the level controller 103 to the water level measuring unit 120, it is possible to prevent hunting of the level controller 103 due to undulations on the water surface. Since the detection of the treated water level 72 in the treated water storage unit 70 is stabilized, the operation of the electrically driven valve 102 in which the opening degree of the valve body is adjusted in conjunction with the treated water level 72 is also stabilized. As a result, it is possible to control the optimum exhaust amount that keeps the treated water level 72 constant.

  In the decarbonation treatment apparatus 10, when the water to be treated 31 is jetted from the jet nozzle 32, the direction of the jet water from the jet nozzle 32 may be substantially downward as shown in FIG. 7B. As shown in FIG. 7A, the direction of the jet water from the jet nozzle 32 is substantially upward, and the free carbonic acid removal performance is superior.

  As shown in FIG. 8, the horizontal axis represents the height from the treated water level 72 to the injection nozzle 32, and the jet flow direction from the injection nozzle 32 was compared with the free carbon dioxide removal rate indicated on the vertical axis. The removal performance was clearly better when the direction was upward than when it was downward. Therefore, it is preferable that the direction of the jet water from the injection nozzle 32 is substantially upward where the free carbonic acid removal rate is high. The reason why the removal rate of free carbonic acid is increased by setting the jet direction upward is considered as follows. In other words, when the jet flow direction is downward, the shape of the jet fluid spreading in a conical shape becomes a so-called cocoon, and the partial pressure of carbon dioxide increases in the part that hinders the exhaust gas from rising, and free carbon dioxide is removed. Although it becomes difficult, it is considered that when the jet flow direction is directed upward, the exhaust gas in the tank portion 20 is likely to rise, and the partial pressure of the carbon dioxide gas is not increased, so that free carbon dioxide is easily removed.

  In the decarbonation apparatus 10, the air diffuser 62 is disposed below the treated water level 72 of the treated water storage unit 70, but the water depth of the air diffuser 62 may be 100 to 500 mm. Considering the aeration efficiency, it seems that the deeper the water depth of the air diffuser 62 is, the better. However, in the decarboxylation device, since the air 61 is generally introduced to the diffuser pipe 62 by a blower in general, if the water depth of the diffuser pipe 62 is deep, the pushing resistance of the air 61 increases, and the required power of the blower increases. In some cases, it becomes difficult to push in the air 61. Therefore, the practical water depth range of the air diffuser 62 is 100 to 500 mm.

  In the decarbonation apparatus 10, the amount of air released from the air diffuser 62 may be 1:10 with respect to the flow rate of the water to be treated 31. In the conventional filling type decarboxylation apparatus 10, (air amount) / (amount of water to be treated 31) is 5 to 20, whereas in the decarbonation apparatus 10, as shown in FIG. The amount of free carbonic acid is almost balanced when the amount is 10 or more. As described above, the removal rate of free carbonic acid is as good as 85% in spite of the fact that the amount of (air amount) / (the amount of water to be treated) is smaller than that of the conventional filling type decarboxylation device.

  As described above, the decarbonation treatment apparatus 10 of the present embodiment exhibits a higher free carbonic acid removal efficiency than the conventional one by combining the spray effect of the injection nozzle 32, the wet wall effect, and the aeration effect. Seem.

  In the present embodiment, the pH of the water to be treated 31 is adjusted to be acidic in advance before the water to be treated 31 flows into the decarboxylation device 10, but the treated water 71 from which the carbonation has been removed by the decarbonation device 10. The pH shifts to the neutral side as free carbonic acid is removed. For this reason, it is preferable that the pH of the treated water 71 falls within a pH range of 5.8 to 8.6 based on tap water without neutralizing with an alkaline agent.

Therefore, the relationship between the pH of the treated water 31 (tap water) and the pH of the treated water 71 was examined. The result is shown in FIG. In addition, the total carbonic acid of the to-be-treated water 31 was 40 mg-CaCO ₃ / L, and the pH of the to-be-treated water 31 was adjusted by adding sulfuric acid.

  From FIG. 10, the pH of the treated water 31 may be adjusted to 5 or more so that the pH of the treated water 71 becomes 5.8 to 8.6 based on tap water without adding an alkaline agent.

  The effect of this invention is demonstrated using the following examples. However, the technical scope of the present invention is not limited to the following examples.

Example 1
The decarboxylation apparatus 10 having the configuration shown in FIG. 11 was used to treat the tap water having the water quality shown below as the water 31 to be treated, and then the pH was adjusted, followed by decarboxylation.

[Quality of treated water]
Water temperature: 13.5 ° C
PH after adjustment: 6.05
Free carbonic acid concentration: 27.5 mg-CaCO ₃ / L
The used decarboxylation apparatus 10 has a diameter of 125 mm and a height of 2800 mm, and is not filled with a filler in order to make the inside of the apparatus hollow.

  The treated water 31 is introduced into the decarboxylation apparatus 10 through the treated water introduction pipe 30 at a flow rate of 500 L / h. About 5% sulfuric acid was added to the water 31 to be treated from the acid introduction tube 40 with a metering pump, and the pH was adjusted to 6.05. The treated water 31 adjusted to be acidic was jetted upward from the jet nozzle 32, and the treated water 71 flowed down to the treated water reservoir 70 along the inner wall.

  The pipe 82 of the treated water outflow part 80 is raised to a height of 2000 mm, the treated water 71 is aerated with the pressurized air 61 from the diffuser pipe 62 installed in the treated water storage part 70, and the treated water level 72 is about 500 mm (± 20%), the output signal of the level controller 103 and the opening of the electric exhaust valve 102 were controlled in conjunction with each other, and the internal pressure of the decarbonation treatment apparatus 10 was maintained at about 20 kPa. At this time, the ratio of the pressurized air amount and the amount of water to be treated was changed in the range of 6 to 12, and the removal rate of free carbonic acid was determined. The result is shown in FIG.

The removal rate of free carbonic acid was determined by the following formula.
Free carbonation removal rate (%) =
(Raw water free carbonic acid-treated water free carbonic acid) ÷ (raw water free carbonic acid) x 100
Free water concentration of raw water; find the component ratio of free carbonic acid from the pH of raw water (Figure 2)
The total carbonic acid concentration of raw water was determined by multiplying the component ratio.
Free carbonic acid concentration of treated water 71: The component ratio of free carbonic acid is determined from the pH of treated water 71,
The total carbonic acid concentration of the treated water 71 was obtained by multiplying the component ratio.

(Comparative Example 1)
In Comparative Example 1, in FIG. 11, the rising height of the conduit 82 of the treated water outflow portion 80 is set to 500 mm, the power source of the level controller 103 is turned off, and the opening degree of the electric exhaust valve 102 is fully opened. Except for these, the same processing as in Example 1 was performed. The result is shown in FIG.

(Contrast between Example 1 and Comparative Example 1)
From the results of Example 1 and Comparative Example 1 (FIG. 12), the free carbonation removal rate of Example 1 in which the internal pressure of the decarboxylation apparatus 10 was increased to 20 kPa was the same as the free carbonation removal rate of Comparative Example 1 that was not pressurized. The tendency was clearly higher.

  Therefore, the decarboxylation processing apparatus 10 of the present invention showed a high free carbonic acid removal rate by holding it in a pressurized state, and had good performance.

  Moreover, in Example 1, the treated water 71 was able to be transferred without using the water pump of the treated water 71 by maintaining the internal pressure of the decarbonation treatment apparatus 10.

(Example 2)
A decarbonation treatment apparatus 10 having the configuration shown in FIG. 13A was used to treat the tap water having the water quality shown below as the water 31 to be treated, and the pH was adjusted, followed by decarboxylation treatment.

[Quality of treated water]
Water temperature: 14.1 ° C
PH after adjustment: 6.02
Free carbonic acid concentration; 28.4 mg-CaCO ₃ / L
The used decarboxylation apparatus 10 has a diameter of 125 mm and a height of 2800 mm, and is not filled with a filler in order to make the inside of the apparatus hollow.

  The treated water 31 is introduced into the decarboxylation apparatus 10 through the treated water introduction pipe 30 at a flow rate of 500 L / h. About 5% sulfuric acid was added to the water 31 to be treated from the acid introduction tube 40 with a metering pump, and the pH was adjusted to 6.02. The treated water 31 adjusted to be acidic was jetted downward from the jet nozzle 32, and the treated water 71 was caused to flow down to the treated water reservoir 70 along the inner wall.

  The pipe 82 of the treated water outflow part 80 is raised to a height of 2000 mm, the treated water 71 is aerated with the pressurized air 61 from the diffuser pipe 62 installed in the treated water storage part 70, and the treated water level 72 is about 500 mm (± The internal pressure of the decarboxylation device 10 was maintained at about 20 kPa by manually adjusting the opening degree of the flow rate adjustment valve 101 so that the flow rate was 20%. The ratio of the amount of pressurized air and the amount of water to be treated at this time was set to 10, and the removal rate of free carbonic acid was determined. As a result, the removal rate of free carbonic acid was 87.1%.

(Comparative Example 2)
In Comparative Example 2, as shown in FIG. 13 (B), the lashing ring (made by TFE, 6φ × 6 mm), which is the filler 130, is filled at the center with reference to 800 mm from the bottom of the decarboxylation apparatus 10a. The layer height was about 1000 mm. Except for these, the same processing as in Example 2 was performed. As a result, the removal rate of free carbonic acid was 84.8%.

(Contrast between Example 2 and Comparative Example 2)
From the results of Example 2 and Comparative Example 2, the decarboxylation apparatus 10 of the present invention that does not use the filler is clearly higher in free carbonic acid removal performance than the conventional decarboxylation apparatus 10 a that uses the filler 130. showed that. That is, it is considered that the decarbonation treatment apparatus 10 of the present invention exhibited a higher free carbonic acid removal efficiency than the conventional filling-type decarbonation treatment apparatus 10a due to the combined action of the spray effect, the wet wall effect, and the aeration effect. It is done.

(Example 3)
Under the same conditions as in Example 2, the decarboxylation treatment of the present invention shown in FIG. 13A was performed continuously for about two weeks. However, the water temperature during this test period was 14.1-14.9 ° C.

  In order to compare the amount of suspended solids contained in water for the treated water 71 immediately after the start of the test and the treated water 71 two weeks later, SDI (Silt Density Index), which is one of the indicators, was measured. However, “Simple SDI” manufactured by Applied Membranes was used for SDI measurement.

  As a result, the SDI of the treated water 71 immediately after the start of the test was 3.5. Further, the SDI of the treated water 71 after 2 weeks was 3.7.

(Comparative Example 3)
Under the same conditions as in Comparative Example 2, as shown in FIG. 13 (B), a lashing ring (made by TFE, 6φ × 6 mm) which is a filler 130 at the center with reference to 800 mm from the bottom of the decarboxylation apparatus 10a. Decarbonation treatment was continuously carried out for about two weeks by a filling type decarboxylation apparatus 10a filled with a packed bed height of about 1000 mm. However, the water temperature during this test period was 14.1-14.9 ° C.

  As in Example 3, the SDI was measured for the treated water 71 immediately after the start of the test and the treated water 71 after 2 weeks.

  As a result, the SDI of the treated water 71 immediately after the start of the test was 3.7. Further, the SDI of the treated water 71 after 2 weeks was 4.8.

(Contrast between Example 3 and Comparative Example 3)
From the results of Example 3 and Comparative Example 3, the decarboxylation apparatus 10 according to the present invention maintained a low SDI value of 3.7 even after 2 weeks from the start of the test. However, in Comparative Example 3 which is the conventional filling-type decarboxylation apparatus 10a, the SDI value after 2 weeks was a large value of 4.8, and the amount of suspended substances contained in the treated water 71 was significantly increased. It has been found.

  Therefore, since the decarboxylation apparatus 10 according to the present invention has a simple structure in the apparatus, it can be expected that the suspended solids hardly increase, and in particular, the growth of bacteria can be suppressed.

As described in detail above, according to the decarboxylation apparatus 10 of the present invention, the water pump for the treated water 71 is not necessary. For example, since the power consumption of the water pump of 1000 m ³ / day is about 5.5 kw, calculating the electricity rate as 15 yen / kw · h can reduce the power cost required for water supply of 700,000 yen or more per year.

  In addition, according to the decarboxylation apparatus 10 of the present invention, since bicarbonate ions and carbonate ions in water are converted into free carbonates, the spray effect, the wet wall effect, and the aeration effect act in a complex manner. Free carbonic acid can be removed with higher efficiency than the conventional decarboxylation apparatus.

  Therefore, if the decarbonated water obtained in the present invention is used as process water, corrosion of the water supply piping and clogging with the scale can be prevented, and as a pretreatment device for food factory process water or pure water production process Can be used.

10 Decarbonation processing equipment,
20 tank section,
30 treated water introduction pipe,
31 treated water,
32 injection nozzle (nozzle part),
40 acid introduction tube,
41 acid for pH adjustment,
50 exhaust section,
51 exhaust gas,
60 air inlet pipe,
61 pressurized air,
62 Air diffuser (air supply part),
70 treated water reservoir,
71 treated water from which free carbonic acid components have been removed,
72 treated water level,
80 treated water outflow part,
82 conduits,
90 treated water tank (equipment using treated water, etc.),
100 displacement control unit,
102 electric exhaust valve (electrically driven valve),
103 level controller (detector),
110 mechanically driven valve,
111 disc,
112 Mechanism capable of setting the force for biasing the valve body in the closing direction,
120 water level measurement unit,
122 The treated water level in the water level measurement unit.

Claims (5)

A decarboxylation device for removing free carbonic acid components from water to be treated,
A tank unit to which water to be treated and air for decarboxylation are supplied;
A treated water introduction pipe connected to the upper part of the tank section for introducing the treated water;
A nozzle part that is provided at an end of the treated water introduction pipe and injects the treated water into the tank part;
An acid introduction pipe connected to the treated water introduction pipe for adding an acid for adjusting the pH of the treated water;
An exhaust part disposed at the top of the tank part for discharging exhaust gas to the outside of the tank part;
An air introduction pipe connected to the lower part of the tank part for introducing the air;
An air supply unit provided at an end of the air introduction pipe to supply the air into the tank unit;
A treated water storage section for storing treated water from which free carbonic acid components have been removed, disposed at the bottom of the tank section;
A treated water outflow section that includes a conduit that communicates with the treated water storage section and rises to a position higher than the treated water storage section, and that feeds the treated water to a device that uses the treated water;
An exhaust amount control unit for controlling an exhaust amount of exhaust gas discharged to the outside of the tank unit in the exhaust unit,
In an apparatus that uses the pressure in the tank and the treated water to maintain the treated water level in the treated water storage unit at a predetermined water level by controlling the exhaust amount in the exhaust unit by the exhaust amount control unit. A decarboxylation apparatus in which the treated water is fed through the treated water outflow portion only by a pressure difference from the pressure. The displacement control unit
A detection unit for detecting a treated water level in the treated water storage unit;
An electrically driven valve disposed in the exhaust part, the electrically driven valve having an opening degree of a valve body adjusted in conjunction with a treated water level detected by the detection part. 2. The decarboxylation apparatus according to 1. A water level measuring unit communicating with the tank unit at a position above the treated water level in the treated water storage unit and a position below the treated water level in the treated water storage unit;
The decarboxylation apparatus according to claim 2, wherein the detection unit detects a treated water level in the treated water storage unit by detecting a treated water level in the water level measurement unit. The displacement control unit
A mechanically driven valve disposed in the exhaust part, comprising a mechanism capable of setting a force for biasing the valve body in the closing direction, and the opening degree of the valve body is adjusted in conjunction with the pressure in the tank part. The decarboxylation apparatus according to claim 1, further comprising a mechanical drive valve.   The said air supply part is immersed in the said treated water stored by the said treated water storage part, and diffuses the said air in the said treated water as described in any one of Claims 1-4. Decarboxylation device.

Images