JP5588952B2 - Carbon dioxide reactor for pH treatment equipment of alkaline raw water - Google Patents

Description

  The present invention relates to an improvement of an apparatus for performing a PH treatment using carbon dioxide gas on highly alkaline raw water discharged from a construction site or various factories, and in particular, carbon dioxide gas can be efficiently mixed and dissolved in highly alkaline raw water. The present invention relates to a carbon dioxide reaction tank for a PH treatment apparatus that can significantly reduce the consumption of carbon dioxide.

  For the treatment of highly alkaline raw water (waste liquid) discharged from construction sites and various factories such as washing water and boiler drainage of concrete mixer trucks, PH treatment using acidic liquids such as sulfuric acid and hydrochloric acid as neutralizing agents The device has been used. However, the PH treatment apparatus using an acid solution as a neutralizing agent has a relatively high risk, and requires a wide installation place. In addition, there is a problem that the maintenance of the apparatus is troublesome.

  Therefore, as an alternative, a PH treatment apparatus using carbon dioxide as a neutralizing agent has been developed, and in recent years, a PH treatment apparatus using carbon dioxide as a neutralizing agent has been widely put into practical use for the treatment of this kind of highly alkaline raw water. ing.

  FIG. 9 shows an example of a PH treatment apparatus using carbon dioxide gas as a neutralizing agent, and discharge of waste liquid (raw water) 42 in the reaction tank 40 by driving a submersible pump 41 provided in the reaction tank 40. While ejecting from an ejector 44 provided at the tip of 43, carbon dioxide gas 46 is press-fitted into a waste liquid 42 in a discharge pipe 43 from a carbon dioxide gas cylinder 45 to neutralize alkali components in the waste liquid 42.

Further, the waste liquid 42 in the waste liquid tank 47 is sucked into the reaction tank 40 through the suction pipe 48 by the negative pressure suction force generated by the operation of the ejector 44 and ejected together with the waste liquid 42.
Further, the waste liquid 42 ′ neutralized by mixing and dissolving the carbon dioxide gas 46 flows into the ventilation chamber 50 from below the partition wall 49 and is discharged from the outlet 51 to the outside.

  On the other hand, the unreacted residual carbon dioxide gas 46 rises in the waste liquid 44, accumulates in the gas reservoir 52 above the reaction tank 40, and is again sucked into the waste liquid 42 through the gas passage 53.

  The PH treatment apparatus of FIG. 9 has an advantage that the amount of carbon dioxide 46 that is a neutralizing agent can be reduced because the unreacted residual carbon dioxide 46 is reused. However, since the submersible pump 41 is provided in the reaction tank 40 and the partition wall 49 is provided to form the vent chamber 50 and the gas reservoir 52, the reaction tank 40 is necessarily increased in size. There is a problem that it is difficult to reduce the size.

  In addition, the dissolution rate of the carbon dioxide gas 46 jetted and mixed into the waste liquid 42 is relatively low. As a result, a considerable portion of the unreacted carbon dioxide gas is discharged from the outlet 51 together with the treated waste liquid 42 '. In other words, there is a problem that the so-called unreacted carbon dioxide recycle rate is poor.

  Furthermore, since the waste liquid 42 in the waste liquid tank 47 is sucked into the reaction tank 40 by using the negative pressure suction force during the operation of the ejector 44, the ejector 44 needs to have a large capacity. Accordingly, there is a problem that the capacity of the submersible pump 41 must be increased.

  Therefore, in recent years, a reaction tank 40 having a configuration as shown in FIG. 10 in which a submersible pump 41 is installed outside the reaction tank 40 has been developed. The reuse rate is improved.

  10, 40 is a reaction tank, 44 is an ejector, 51 is an outlet for treated waste liquid 42 ', 52 is a gas reservoir, 53 is a gas passage, 54 is a waste liquid supply pipe, and 55 is carbon dioxide gas 46. The carbon dioxide gas cylinder and the waste liquid supply pump are not shown in the figure.

  The waste liquid 42 is ejected from the waste liquid supply pipe 54 into the reaction tank 40 through the ejector 44 by pump pressurization. The carbon dioxide gas 46 is press-fitted into the waste liquid supply pipe 54 outside the reaction tank 40, and the waste liquid 42 mixed and dissolved with the carbon dioxide gas is ejected from the tip of the ejector 44.

  Further, the unreacted portion of the carbon dioxide gas 46 mixed into the waste liquid 42 moves upward in the waste liquid 42 in the form of bubbles 46a and stays in the upper space of the reaction tank 40 (that is, the gas reservoir 52).

  Further, the operation of the ejector 44 generates a so-called vacuum suction force, and the vacuum suction force causes the unreacted residual carbon dioxide gas 46 ′ in the gas reservoir 52 to flow through the ejector 44 through the gas passage 53. 42 is mixed again.

  In the reaction tank 40 having the structure shown in FIG. 10, although the reaction tank 40 can be downsized, the unreacted residual carbon dioxide gas 46 'is discharged from the outlet 51 together with the treated waste liquid 42'. It easily flows out to the outside, so that the so-called unreacted residual carbon dioxide gas 46 ′ has a low recovery rate, and the consumption of the carbon dioxide gas 46 cannot be significantly reduced.

JP 2001-340878 A JP 2008-194657 A

  The present invention has the above-described problem in the carbon dioxide reaction tank of the conventional PH treatment apparatus, that is, the unreacted residual carbon dioxide is easily discharged from the treated waste liquid outlet to the outside. It is intended to solve the problem that carbon dioxide consumption is not sufficiently reduced due to the low recovery rate of carbon dioxide, and by increasing the solubility of carbon dioxide mixed into the waste liquid without using an ejector Therefore, the present invention intends to provide a carbon dioxide gas reaction tank for a PH treatment apparatus that can reduce the consumption of carbon dioxide gas and greatly reduce the size of the reaction tank.

The invention of claim 1 of the present application is an outer cylinder 24 having a raw water discharge pipe 29 on the side wall of the upper end portion and a concentric arrangement inside the outer cylinder 24 in a carbon dioxide reaction tank used in a pH treatment apparatus for alkaline raw water. The inner cylinder 26 whose length is shorter than that of the outer cylinder 24 and whose lower end opening is enlarged in a trumpet shape, and the nozzle 27a provided at the front end of the inner cylinder 26 from the upper end opening of the inner cylinder 26 is provided above the inner cylinder 26. A raw water supply pipe 27 that is positioned concentrically and is inserted concentrically, and a carbon dioxide gas supply pipe 28 that is provided outside the inner cylinder 26 of the raw water supply pipe 27 and supplies carbon dioxide C to the inside of the inner cylinder 26. consists of a, with reversing the flow direction by emitting mixed water alkaline raw water and carbon dioxide gas injected into the inner cylinder 26 from the nozzle 27a from the lower end opening of the inner cylinder 26 into the outer cylinder 24, the trumpet-shaped Outer cylinder 24 and inner cylinder 2 made smaller by expanding the diameter The mixed water to flow through the gap G between, in which the basic configuration of the invention that discharged from the raw water discharge pipe 29 to the outside.

According to a second aspect of the present invention, in the first aspect of the invention, the carbon dioxide gas supply pipe 28 is arranged in a direction orthogonal to the axis of the raw water supply pipe 27.

According to a third aspect of the present invention, in the first aspect of the invention, the inner cylinder 26 has an inner diameter of ¼ to ３ of the inner diameter of the outer cylinder 24, and the inner cylinder 26 has a length equal to that of the outer cylinder 24. 80 to 90% of the length.

In the present invention, the mixed water of raw water and carbon dioxide gas is ejected from the nozzle 27a to the inside of the inner cylinder 26, and is discharged to the outer cylinder 24 through the trumpet-shaped raw water reversing port 27b at the lower end of the inner cylinder 26. The flow direction is reversed, and the water is discharged to the outside through the raw water discharge pipe 29 provided on the upper end side wall of the outer cylinder 24.
As a result, the inner cylinder 26 functions as a carbon dioxide gas dissolution chamber, and water pressure corresponding to the depth of the outer cylinder 24 is applied to the mixed water in the inner cylinder 26 and the outer cylinder 24, so that the carbon dioxide gas in the mixed water is reduced. As a result, the solubility of carbon dioxide is improved and the amount of carbon dioxide required for neutralization of alkaline raw water is reduced, resulting in a significant reduction in the running cost of the alkali treatment equipment. Can do.

  Further, by increasing the length dimension of the inner cylinder 26 and forming the tip opening thereof in a trumpet shape, the passage gap G in which the mixed water flows reversely between the outer cylinder 24 and the inner cylinder 26 is narrowed. As a result, bubbles of carbon dioxide are confined in the inner cylinder, so that the dissolution of carbon dioxide into the raw water is further promoted, and the carbon dioxide released into the raw water is used without waste.

It is a top view of PH processing apparatus to which the carbon dioxide reaction tank concerning the present invention is applied. It is a front view of PH processing apparatus. It is a left view of PH processing apparatus. It is a right view of PH processing apparatus. It is a slope view of a PH processing apparatus. It is a schematic explanatory drawing of the raw | natural water processing system | strain of PH processing apparatus. It is a top view of the carbon dioxide reaction tank concerning the present invention. FIG. 8 is a cross-sectional view taken along the line II in FIG. 7. It is explanatory drawing which shows an example of PH processing apparatus using the conventional carbon dioxide gas. It is a cross-sectional schematic diagram of the carbon dioxide reaction tank currently used with the PH treatment apparatus of conventional alkaline wastewater. It is a diagram which shows the relationship between the carbon dioxide gas flow rate and the PH value of processed raw water in the reaction tank of this invention, and the reaction tank of an ejector system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a plan view showing an example of a PH treatment apparatus to which a carbon dioxide reaction tank according to the present invention is applied, FIG. 2 is a front view thereof, FIG. 3 is a left side view of FIG. 1, and FIG. FIG. FIG. 5 is a perspective view of the PH processing apparatus.

  The PH treatment apparatus 1 includes a carbon dioxide reaction tank 2, an intermediate tank 3, a circulation tank 4, a discharge tank 5, a control panel 6, a carbon dioxide supply apparatus 7, and a discharge tank PH electrode 8 as shown in FIGS. And an intermediate tank PH electrode 9 and the like, and raw water (waste liquid) A having a maximum pH of 12 is supplied from a raw water pit and / or a raw water tank (not shown) separately via a raw water pump (not shown). The treated raw water B supplied from the water inlet 10 into the reaction tank 2 and processed to PH 5.8 to 8.6 is discharged from the outlet 11 to the outside.

  In FIGS. 1 to 5, 12 is a raw water tank PH electrode, 13 is a holder for the raw water tank PH electrode 12, 14 is a carbon dioxide supply pipe, 15 is a circulation pump, and 16 and 17 are drains. A valve 18 is a gate valve.

Table 1 shows the main specifications of the PH processing apparatus 1. The external dimensions of the apparatus are a width of 1070 mm, a depth of 1100 mm, and a height of 1590 mm.

  FIG. 6 is a schematic explanatory diagram of the raw water treatment system and the control system of the PH treatment apparatus. The raw water A is supplied from the raw water pit 19 and / or the raw water tank 20 to the raw water pit pump 21 and / or the raw water tank pump 22 separately provided. The raw water A sent into the carbon dioxide reaction tank 2 according to the present invention forming the PH treatment apparatus 1 and neutralized by the dissolution of the carbon dioxide gas C passes through the intermediate tank 3, the circulation tank 4, the discharge tank 5, and the outlet 11. It is discharged from the outside.

The raw water tank 20 and the like, the intermediate tank 3 and the discharge tank 5 are provided with PH electrodes 12, 9 and 8, and PH values of the raw water A and the treated raw water B are recorded and displayed on the control panel 6. .
The amount of carbon dioxide C supplied to the carbon dioxide reaction tank 2 is controlled via the controller 6a of the control panel 6 based on the detected PH value of each of the PH electrodes 12, 9, and 8, so-called feed forward. The raw water A is subjected to PH treatment by both control and feedback control.

Further, when an abnormality occurs in the PH value in the intermediate tank 3 or the discharge tank 5, the circulation pump 15 is automatically driven to circulate a part of the treated raw water B to the reaction tank 2, and the treated raw water B The PH value is held at the set value.
In FIG. 6, 7a is a pressure regulator of the carbon dioxide supply device 7, 7b is a flow rate regulator (electropneumatic regulator), 7c is a solenoid valve, 6b is a PH indicator, 6c is a PH recorder, 4a, 19a and 20a are float type liquid level detectors.

  7 is a plan view of a carbon dioxide reaction tank for a PH treatment apparatus according to the present invention, and FIG. 8 is a cross-sectional view taken along the line II in FIG. That is, the carbon dioxide reaction tank 2 according to the present invention corresponds to the reaction tank 2 in FIGS. 1 to 6, and the alkaline component of the raw water A is dissolved by dissolving the carbon dioxide C into the raw water A. Neutralization is performed to reduce the PH value to a set value (PH 5.8 to 8.6).

  7 and 8, 24 is an outer cylinder, 25 is a lid, 26 is an inner cylinder, 27 is a raw water supply pipe, 28 is a carbon dioxide supply pipe, and 29 is a raw water discharge pipe.

  That is, the carbon dioxide gas reaction tank 2 includes a vertically long outer cylinder 24, an inner cylinder 26 slightly shorter than the outer cylinder 24 provided coaxially with the outer cylinder 24, and a nozzle provided at the tip portion from the upper opening of the inner cylinder 26. The raw water supply pipe 27 inserted and supported 27a into the inner cylinder 26 and the carbon dioxide gas supply pipe 28 and the like positioned outside the inner cylinder 26 and attached to the axis of the raw water supply pipe 27 at right angles. Has been.

  The outer cylinder 24 is a cylindrical body having an inner diameter of 300 to 400 mmφ and a length of about 800 to 1200 mm, and its upper opening fixes a lid body 25 welded to the upper end of the inner cylinder 26 to a flange 24a welded to the upper end portion of the outer cylinder. By being airtightly closed. Further, a discharge pipe 29 for the treated raw water is provided on the upper end side wall of the outer cylinder 24, and the lower end of the outer cylinder 24 is tapered to form a drain valve mounting port 24b. Has been.

The inner cylinder 26 is a cylindrical body having an inner diameter of 100 to 150 mmφ and a length of about 700 to 1100 mm. By fixing the upper end of the inner cylinder 26 to the lid body 25, it is inserted into the outer cylinder 24 concentrically therewith, It is fixed.
Moreover, the front-end | tip part 26a of the inner cylinder 26 is expanded in the trumpet shape, and becomes the raw | natural water inversion port 27b. In other words, the gap G between the inner and outer cylinder tubes 24 and 26 is narrowed, and the mixed water that has descended from the upper part through the inside of the inner cylinder 24 is reversed and becomes an upward flow. It passes between the inner and outer cylinders 24 and 26 and is discharged from the raw water discharge pipe 29 to the outside.

  The raw water supply pipe 27 is formed of a short pipe having a pipe diameter of about 50A to 65A, and is inserted concentrically into the inner cylinder 26 with the nozzle 27a provided at the tip facing the inside of the inner cylinder 26. Then, it is detachably supported and fixed to the upper surface of the lid 25 via the fixture 30.

  Further, a carbon dioxide gas supply pipe 28 is fixedly attached to the carbon dioxide gas supply pipe 28 at a position located outside the outer cylinder 24 in a direction perpendicular to the axial center thereof. Carbon dioxide C is jetted out and mixed in a direction perpendicular to the flow direction of the raw water A.

The raw water supply pipe 27 is supplied with raw water A having a pressure of 0.15 to 0.6 kg / cm ² and a flow rate of 100 to 400 l / min. Further, carbon dioxide gas C having a gas pressure of 1 to ² kg / cm ² is injected into the raw water A at a flow rate of 25 to 80 l / min in the vertical direction (when the pH value of the raw water is 12). Carbon dioxide C is mixed into the raw water A.

  The mixed water of the raw water A and the carbon dioxide gas C is ejected from the nozzle 27a into the inner cylinder 26, and is stirred and mixed in the inner cylinder 26 that becomes the carbon dioxide gas chamber, whereby the carbon dioxide gas C enters the raw water A. Dissolved. Thereby, it reacts with the carbon dioxide gas C in which the alkaline component in the raw water A is dissolved and is neutralized, and its PH value is lowered.

  In particular, a water pressure corresponding to the liquid level of the outer cylinder 24 is applied to the inner cylinder 26, and the gap G is made smaller by making the lower end opening of the inner cylinder 26 a trumpet-shaped opening so that the carbon dioxide gas bubbles Ca are contained in the inner cylinder 26. By making it contain in 26, the carbon dioxide gas bubble Ca will be less compressed to the outside and compressed by water pressure, and its solubility will be greatly improved.

  The length of the inner cylinder 26 is set to about 80 to 90% of the length of the outer cylinder 24, and the inner diameter of the inner cylinder 26 is set to about 1/4 to 1/3 of the inner diameter of the outer cylinder 24. It has been confirmed from the results of the dissolution test that this is the best in increasing the solubility of carbon dioxide gas.

Next, the characteristic test result of the carbon dioxide reaction tank 2 according to the present invention will be described.
First, a small model of the reaction tank 2 of the ejector type shown in FIG. 10 and the carbon dioxide reaction tank 2 shown in FIG. 8 was created. That is, in FIG. 10 and FIG. 8, the raw water to be supplied with the height of the reaction tank 2 (the height of the outer cylinder) of 1000 mm, the inner diameter (the inner diameter of the outer cylinder) of 200 mm, the inner diameter of the inner cylinder 26 of 65 mmφ, and the nozzle diameter of 16 mmφ. The relationship between the amount of carbon dioxide supplied and the PH value after treatment when the flow rate of A and the PH value were the same was investigated.

Table 2 shows the results of actual measurement of the relationship between the carbon dioxide gas flow rate and the treated raw water PH value when the raw water treatment amount is 100 L / min, using the raw water PH value as a parameter.

   (A), (b), and (c) of FIG. 11 are diagrams showing the test results of Table 2 above.

As is apparent from the results in Table 2, the PH value of the treated raw water C is lower in the double-cylinder carbon dioxide reaction tank according to the present invention than in the case of the conventional ejector-type reaction tank. It can be seen that the solubility of the mixed carbon dioxide gas is improved and the neutralization reaction efficiency is greatly improved.
Specifically, as is clear from FIG. 11 (a), the difference in the flow rate of carbon dioxide gas when the raw water PH value is 11.7 is about 5 L / min, and the amount of gas used is 300 L / h per hour. Reduction is possible.
That is, in the present invention, the utilization efficiency of carbon dioxide gas is improved, and the consumption of carbon dioxide gas can be greatly reduced.

  Further, in the carbon dioxide reaction tank for a PH treatment apparatus according to the present invention, carbon dioxide is used as a neutralizing agent, but oxygen gas or ozone gas may be used instead of carbon dioxide. Needless to say, an oxygen gas reaction tank for a PH processing apparatus or an ozone gas reaction tank for a PH processing apparatus may be used.

  The present invention can be used not only for PH treatment equipment for cement waste water and boiler waste water, but also for PH treatment of alkaline waste liquid in all industries. It is also possible to use oxygen gas or ozone gas as a neutralizing agent instead of carbon dioxide gas.

A Raw water (waste liquid)
B treated raw water (treated wastewater)
C Carbon dioxide gas Ca Carbon dioxide bubble G Gap 1 PH treatment device 2 Carbon dioxide reaction tank 3 Intermediate tank 4 Circulating tank 4a Liquid level detector 5 Discharge tank 6 Control panel 6a Controller 6b PH indicator 6c PH recorder 7 Carbon dioxide supply Device 7a Pressure regulator 7b Flow regulator 7c Solenoid valve 8 PH electrode for discharge tank 9 PH electrode for intermediate tank 10 Raw water inlet 11 Outlet 12 Raw water tank PH electrode 13 Raw water tank PH electrode storage holder 14 Carbon dioxide Supply pipe 15 Circulation pump 16/17 Drain valve 18 Gate valve 19 Raw water pit 19a Liquid level detector 20 Raw water tank 20a Liquid level detector 21 Raw water pit pump 22 Raw water tank pump 23 Carbon dioxide cylinder 24 Outer cylinder 24a Flange 24b Drain valve installation Port 25 lid body 26 inner cylinder 26a trumpet-shaped tip opening 27 raw water supply pipe 27a nozzle 27b raw water reversing port 28 Carbon dioxide supply pipe 29 Raw water discharge pipe 30

Claims (3)

In the carbon dioxide reaction tank used in the alkaline raw water PH treatment apparatus, the outer cylinder having the raw water discharge pipe on the side wall of the upper end, the concentric arrangement inside the outer cylinder , the length is shorter than the outer cylinder, and the lower end An inner cylinder whose opening is enlarged in a trumpet shape, and a raw water supply pipe which is inserted concentrically with the nozzle provided at the distal end located above the inner cylinder from the upper end opening of the inner cylinder, A carbon dioxide gas supply pipe that is provided at an external position from the inner cylinder of the raw water supply pipe and supplies carbon dioxide gas to the inside of the inner cylinder. The inner cylinder is a mixture of alkaline raw water and carbon dioxide gas jetted into the inner cylinder from the nozzle. Is discharged from the lower end opening of the outer cylinder into the outer cylinder to reverse the direction of flow , and the mixed water is made to flow through the gap G between the outer cylinder and the inner cylinder, which has been reduced by the trumpet-shaped diameter expansion, from the raw water discharge pipe to the outside. Alkaline raw material characterized in that it is configured to discharge to Carbon dioxide reactor for water PH treatment equipment.   The carbon dioxide gas reaction tank for alkaline raw water PH treatment apparatus according to claim 1, wherein the carbon dioxide gas supply pipe is arranged in a direction orthogonal to the axis of the raw water supply pipe.   2. The alkaline raw water PH treatment according to claim 1, wherein an inner diameter of the inner cylinder is set to ¼ to 内径 of an inner diameter of the outer cylinder, and the length of the inner cylinder is set to 80 to 90% of the length of the outer cylinder. Carbon dioxide reaction tank for equipment.