JP4577006B2 - Wastewater treatment equipment - Google Patents

Description

  The present invention relates to a wastewater treatment apparatus that neutralizes and cools boiler wastewater.

  The boiler water inside the steam boiler can, which generates steam by heating the feed water, is decomposed by hydrogen carbonate ions and carbonate ions contained in the feed water to produce hydroxide ions. Concentration becomes increasingly alkaline. When discharging such alkaline can water, it is necessary to neutralize to a predetermined pH so as to conform to the drainage standards defined in the regulations.

  Further, the can water is at a high temperature, and when the can water is discharged, it must be cooled to a predetermined temperature determined by the drainage standard.

As an apparatus for performing such wastewater treatment such as neutralization and cooling, Patent Document 1 discloses a wastewater treatment apparatus including a boiler wastewater neutralizing means and a boiler wastewater cooling means.
JP 2001-293484 A

  However, in the conventional wastewater treatment apparatus, the neutralization means and the cooling means are provided in separate systems, and the apparatus configuration is complicated, and the apparatus must be a large apparatus. Therefore, it is difficult to install in a place where it is difficult to secure a space.

  The problem to be solved by the present invention is to realize a waste water treatment apparatus that has a simplified structure and can be miniaturized.

This invention was made in order to solve the said subject, The invention of Claim 1 is equipped with the waste water treatment equipment provided with the ejector which sucks and mixes boiler exhaust gas to boiler wastewater, and the heat exchanger which cools boiler wastewater. A boiler wastewater storage tank, a circulation path for circulating boiler wastewater in the storage tank in which the ejector and the heat exchanger are arranged in series, and boiler exhaust gas used for neutralization are supplied to the ejector Neutralizing agent supply path, cooling water supply path for supplying cooling water used for cooling boiler drainage circulating through the circulation path to the heat exchanger, and neutralizing agent supply provided in the neutralizing agent supply path An ejector that opens and closes the neutralizer supply valve and the air valve based on the pH of the boiler wastewater. Boiler switching between gas supply and air suction, also that it is so on the basis of the water temperature of the boiler waste water by opening and closing the cooling water supply valve is switched to stop the supply of cooling water to the heat exchanger Features.

In the invention according to the first aspect , the boiler wastewater in the storage tank is neutralized by the ejector while being circulated through the circulation path, and is cooled by the heat exchanger .

Then , the ejector is controlled until the boiler wastewater reaches a predetermined pH. On the other hand, the heat exchanger is controlled until the boiler waste water reaches a predetermined water temperature.

According to the first aspect of the present invention, since the ejector and the heat exchanger are arranged in series in a circulation path for circulating the boiler waste water, the configuration of the apparatus can be simplified and the apparatus can be reduced in size. Can be realized. Further, since the boiler wastewater is cooled while being circulated through the circulation path, the boiler wastewater can be efficiently and stably discharged.

Furthermore, a neutralizing agent supply path for supplying boiler exhaust gas used for neutralization to the ejector, a cooling water supply path for supplying cooling water used for cooling boiler drainage circulating through the circulation path to the heat exchanger, A neutralizing agent supply valve and an air valve provided in the neutralizing agent supply path; and a cooling water supply valve provided in the cooling water supply path, and the neutralizing agent supply valve based on the pH of boiler drainage Opening and closing the air valve to switch between supply of boiler exhaust gas to the ejector and air suction, and opening and closing the cooling water supply valve based on the temperature of the boiler drain water to supply cooling water to the heat exchanger because so switch the stop, and control of the ejector, Ki de be performed separately and control of the heat exchanger, of the neutralization and two wastewater treatment cooling, one or Water treatment is completed, if the other wastewater treatment is not sufficient, it is possible to stop only complete wastewater treatment. Accordingly, the two wastewater treatments, neutralization and cooling, can be performed appropriately.

Hereinafter, the best mode for carrying out the wastewater treatment apparatus according to the present invention will be described.
The waste water treatment apparatus in which the present invention is implemented is for neutralizing the alkaline blow waste water from the steam boiler, that is, the boiler waste water, cooling it, and discharging it as treated water that meets the waste water standard.

First, the first embodiment will be described. The wastewater treatment apparatus in the first embodiment includes an ejector that sucks and mixes boiler exhaust gas into boiler wastewater and a heat exchanger that cools boiler wastewater. The ejector and the heat exchanger are respectively arranged in series in a drainage path for circulating boiler drainage.

The ejector takes in the neutralizing agent from the outside into the drainage path and mixes the neutralizing agent with the boiler drainage. The ejector can be configured by connecting a neutralizing agent supply path to the drainage path, and the neutralizing agent is taken in and mixed with the boiler drainage at a connection portion of the neutralizing agent supply path. . Here, as the neutralizing agent, acidic chemicals such as hydrochloric acid, sulfuric acid and nitric acid, acidic gas such as carbon dioxide, boiler exhaust gas containing carbon dioxide, and the like can be used.

The ejector is provided at the connecting portion and sucks the neutralizing agent from the neutralizing agent supply path using a negative pressure generated by the flow of boiler waste water, and mixes the neutralizing agent and boiler waste water. It is adapted to discharge to. Specifically, the ejector has a supply port and a discharge port for boiler drainage, and the supply port and the discharge port are respectively connected to the drainage path. The ejector has a suction port for the neutralizing agent, and the suction port is connected to the neutralizing agent supply path. When such an ejector is provided, the neutralizing agent can be efficiently taken in and mixing of the neutralizing agent and boiler waste water can be promoted. Furthermore, the neutralizing agent supply path may be provided with an on-off valve in order to control the supply and stop of the neutralizing agent.

The use of boiler exhaust gas as a neutralizing agent for the boiler waste water, Ri points or RaYoshimi Tekidea safety and running costs, as for sucking mixed boiler exhaust gas to the boiler effluent, the ejector of excellent neutralizing efficiency To preferred. When the neutralization by such a structure is demonstrated concretely, the boiler waste_water | drain which flows through the said drainage path will be taken in in the said ejector first. In the ejector, the boiler exhaust gas sucked from the neutralizing agent supply path is mixed with the boiler waste water. As a result, the boiler exhaust gas dissolves in contact with the boiler wastewater, and the boiler wastewater is neutralized. Furthermore, since the boiler wastewater is agitated by the turbulent flow effect generated in the ejector, it can be neutralized efficiently. Further, since the ejector does not have a movable part, it is difficult to cause failure or deterioration due to the heat of the boiler exhaust gas. For this reason, boiler exhaust gas can be stably supplied with respect to boiler waste_water | drain.

It said heat exchanger comprises a waste water inlet for supplying the boiler waste water flowing through the pre-Symbol drainage pathway, and a waste water outlet for discharging the cooled boiler effluent. The heat exchanger further includes a cooling water inlet for supplying cooling water and a cooling water outlet for discharging the heat-exchanged cooling water.

According to such a wastewater treatment apparatus of the first embodiment, the ejector and the heat exchanger are arranged in series in the drainage path. For this reason, compared with the case where the ejector and the heat exchanger are provided in separate systems, the configuration of the apparatus can be simplified and the apparatus can be downsized.

Next, a second embodiment will be described. This second embodiment is a modification of the first embodiment. The wastewater treatment apparatus of the second embodiment includes a storage tank that stores boiler wastewater, and a circulation path that circulates boiler wastewater in the storage tank, and an ejector and a heat exchanger are arranged in series in this circulation path. ing. Further, a circulation pump is provided in the circulation path, and the boiler drainage in the storage tank is circulated by the circulation pump.

The ejector takes in a neutralizing agent from the outside into the circulation path and mixes the neutralizing agent with boiler waste water. The ejector can be configured by connecting a neutralizing agent supply path to the circulation path, and the neutralizing agent is taken in at a connection portion of the neutralizing agent supply path and is discharged to the circulating boiler drainage. Mixed. Here, the same neutralizing agent as in the first embodiment can be used.

In the ejector provided in the connection portion, the supply port and the discharge port are respectively connected to the circulation path, and the suction port is connected to the neutralizing agent supply path. When such an ejector is provided, the neutralizing agent can be efficiently taken in and mixing of the neutralizing agent and boiler waste water can be promoted. Furthermore, the neutralizing agent supply path may be provided with an on-off valve in order to control the supply and stop of the neutralizing agent.

The ejector is preferably configured to use boiler exhaust gas as the neutralizing agent, and particularly preferably configured to provide the ejector at the connecting portion. The effect of neutralization by such a configuration is as described in the first embodiment.

The heat exchanger has the same configuration as that of the first embodiment, and the drainage inlet and the drainage outlet are respectively connected to the circulation path.

Now, the storage tank is provided with a pH sensor for detecting the pH of the stored boiler drainage and a temperature sensor for detecting the water temperature. Based on the pH detected by the pH sensor, neutralization control by the ejector , specifically, control of supply or stop of the neutralizing agent is performed. Further, based on the water temperature detected by the temperature sensor, cooling control by the heat exchanger , specifically, control of supply or stop of the cooling water is performed.

  According to such a waste water treatment apparatus of the second embodiment, the boiler waste water is neutralized while being circulated through the circulation path and cooled, so that efficient and stable waste water treatment can be performed.

In addition, since the ejector and the heat exchanger are arranged in series in the circulation path, only one circulation pump is required to send boiler wastewater to these means. For this reason, a pump can be shared and cost reduction can be aimed at.

Further, in the wastewater treatment apparatus of the second embodiment, neutralization is performed based on the pH of the boiler wastewater detected by the pH sensor, and cooling is performed based on the water temperature of the boiler wastewater detected by the temperature sensor. Be controlled. That is, the ejector controls the supply of the neutralizing agent until the pH of the boiler drainage reaches a predetermined value determined by the drainage standard, and stops the supply of the neutralizing agent when the pH reaches the predetermined value. Is done. On the other hand, the heat exchanger is controlled to supply cooling water until the temperature of the boiler waste water reaches a predetermined value determined by the drainage standard, and to stop supplying the cooling water when the water temperature reaches the predetermined value. . In this way, by performing neutralization control and cooling control separately, the two wastewater treatments of neutralization and cooling can be performed appropriately.
The two wastewater treatments, neutralization and cooling, can be performed appropriately.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic explanatory view showing the configuration of a wastewater treatment apparatus for carrying out the present invention.

  In FIG. 1, the waste water treatment apparatus 1 neutralizes the alkaline blow waste water (hereinafter referred to as “boiler waste water”) from the steam boiler 2 with the carbon dioxide gas contained in the boiler exhaust gas, and cools the waste water. It is discharged as treated water that meets the standards.

  The wastewater treatment apparatus 1 includes a drainage path 3 for supplying boiler drainage from the steam boiler 2, a boiler drainage storage tank 4, and a neutralizer supply path 5 for supplying boiler exhaust gas used for neutralization.

  The steam boiler 2 includes an exhaust pipe 6 that discharges exhaust gas that burns fuel to the outside. The exhaust pipe 6 and the neutralizing agent supply path 5 are connected so as to extract a part of the exhaust gas. ing.

Both ends of a circulation path 7 for circulating the stored boiler drainage are connected to the storage tank 4, and the circulation path 7 is connected to the circulation pump 8, the heat exchanger 9, and the water pressure detection in this order from the upstream side. Means 10 and ejector 11 are arranged in series.

The heat exchanger 9 is provided with a drainage inlet 12 for supplying the boiler waste water flowing in the pre-Symbol circulation path 7, and a waste water outlet 13 for discharging the cooled boiler effluent. The heat exchanger 9 further includes a cooling water inlet 14 for supplying cooling water and a cooling water outlet 15 for discharging the heat-exchanged cooling water. A cooling water supply path 16 is connected to the cooling water inlet 14, and a cooling water supply valve 17 is provided in the cooling water supply path 16. The cooling water supply valve 17 is controlled to be opened and closed by a control unit 18.

  The water pressure detection means 10 is, for example, a pressure switch or a pressure sensor, and a signal from the water pressure detection means 10 is input to the control unit 18.

The ejector 11 is pre-Symbol circulation path 7 the neutralizer supply path 5 and drainage supply port 19 is connected and a neutralizing agent suction port 20 to be connected. And this ejector 11 takes in boiler waste_water | drain from the said waste_water | drain supply port 19, sucks boiler waste gas from the said neutralizer suction port 20, and mixes with boiler waste_water | drain. Boiler wastewater mixed with boiler exhaust gas is injected into the storage tank 4 from the discharge port 21 of the ejector 11.

  Here, since the ejector 11 does not have a movable part, it is difficult to cause failure or deterioration due to the heat of the boiler exhaust gas. For this reason, boiler exhaust gas can be stably supplied to and mixed with boiler wastewater.

  Further, the boiler exhaust gas is supplied to the ejector 11 or is stopped by opening and closing a neutralizer supply valve 22 and an air valve 23 provided in the neutralizer supply path 5. (I will explain in detail later). The neutralizer supply valve 22 and the air valve 23 are controlled to be opened and closed by the control unit 18.

  The storage tank 4 is provided with a temperature sensor 24 and a pH sensor 25 for detecting the water temperature and pH of the stored boiler drainage. The bottom of the storage tank 4 is connected with a neutralized boiler drainage, that is, a treated water discharge path 26 for discharging treated water to the outside of the system. A discharged valve 27 is connected to the treated water discharge path 26. Is provided. The discharge valve 27 is controlled to open in response to a command from the control unit 18 when the water quality detected by the temperature sensor 24 and the pH sensor 25 reaches a water temperature and a pH that meet the drainage standard.

  Here, the operation of the waste water treatment apparatus 1 will be described. Boiler drainage from the steam boiler 2 is stored in the storage tank 4 through the drainage path 3. The stored boiler drainage circulates in the circulation path 7 by driving the circulation pump 8 based on a command from the control unit 18. The boiler wastewater is cooled and neutralized in the circulation path 7.

First, the cooling of the boiler wastewater will be specifically described. The boiler wastewater flowing through the circulation path 7 is introduced from the wastewater inlet 12 into the internal flow path (not shown) of the heat exchanger 9. When the cooling water supply valve 17 is opened in this state, cooling water is supplied from the cooling water inlet 14 to the outside of the internal flow path via the cooling water supply path 16. This cooling water takes heat from the boiler waste water and is discharged from the cooling water outlet 15. The cooled boiler waste water is discharged from the drain outlet 13 to the circulation path 7 and recirculates into the storage tank 4.

  Next, the neutralization of the boiler wastewater will be specifically described. The boiler wastewater circulating in the circulation path 7 is neutralized by the boiler exhaust gas supplied from the neutralizer supply path 5 by the action of the ejector 11. The Specifically, the ejector 11 takes in boiler wastewater from the wastewater supply port 19 and sucks boiler exhaust gas supplied from the neutralizing agent supply path 5 from the neutralizer suction port 20. Mix with boiler exhaust gas. Thus, the boiler waste water and the boiler exhaust gas are efficiently brought into contact with each other, and the boiler waste water is agitated by the turbulent flow effect generated in the ejector 11 to dissolve and neutralize the boiler exhaust gas into the boiler waste water. And this boiler waste_water | drain is injected in the said storage tank 4 from the said discharge outlet 21. FIG. Here, the boiler exhaust gas that could not be dissolved into the boiler drainage in the ejector 11 is blown out into the storage tank 4 in the form of bubbles, and is refined and dissolved in the boiler drainage to promote neutralization.

By the way, in this embodiment, cooling by the heat exchanger 9 is controlled by the controller 18 based on the water temperature of the boiler drain detected by the temperature sensor 24. Further, based on the pH of the detected boiler drained by the pH sensor 25, and controls the neutralization by the ejector 1 1 by the controller 18.

First, the cooling control by the heat exchanger 9 will be specifically described. When the temperature of the boiler waste water detected by the temperature sensor 24 exceeds a predetermined value determined by the waste water standard, the control unit 18 opens the cooling water supply valve 17. As a result, cooling water is supplied to the heat exchanger 9 via the cooling water supply path 16, and the boiler drainage is continuously cooled. On the other hand, when the water temperature of the boiler wastewater detected by the temperature sensor 24 becomes equal to or lower than a predetermined value determined by the wastewater standard, the control unit 18 closes the cooling water supply valve 17. As a result, the supply of cooling water to the heat exchanger 9 is interrupted, and the cooling of the boiler drain is stopped.

  Next, the neutralization control by the ejector 11 will be specifically described. When the pH of the boiler wastewater detected by the pH sensor 25 exceeds a predetermined value determined by the wastewater standard, the control unit 18 opens the neutralizer supply valve 22 and the air valve 23 is closed. As a result, the ejector 11 can suck the boiler exhaust gas through the neutralizing agent supply path 5, and the boiler waste water is continuously neutralized. On the other hand, when the pH of the boiler wastewater detected by the pH sensor 25 is equal to or lower than a predetermined value determined by the wastewater standard, the control unit 18 closes the neutralizing agent supply valve 22 and The air valve 23 is opened. As a result, outside air is sucked into the ejector 11, and neutralization of boiler drainage is stopped. As described above, when the outside air is sucked when the boiler exhaust gas is not supplied, vibration caused by pressure fluctuation generated in the ejector 11 is suppressed.

  As described above, cooling control and neutralization control are performed individually until the boiler drainage in the storage tank 4 reaches the water temperature and pH determined by the drainage standard while circulating through the circulation path 7. . Then, when the boiler drainage in the storage tank 4 reaches a water temperature and pH that meet drainage standards, the control unit 18 opens the discharge valve 27 and the boiler drainage via the treated water discharge path 26. Is discharged outside the system.

  By the way, the waste water treatment apparatus 1 is configured to detect the water pressure of boiler waste water flowing into the ejector 11 by the water pressure detecting means 10. For example, when a failure of the circulation pump 8 or clogging of the circulation path 7 occurs, the water pressure of the boiler drain to the ejector 11 decreases, and a sufficient negative pressure cannot be obtained at the neutralizer suction port 20. . For this reason, the amount of intake air of the boiler exhaust gas decreases, and the predetermined neutralization ability cannot be exhibited. Therefore, in this configuration, when the water pressure of the boiler drainage becomes a predetermined value or less, the control unit 18 issues an alarm or the like to notify the abnormality to the outside. As a result, maintenance of the circulation pump 8 and the circulation path 7 and the like can be quickly performed, and a decrease in the intake amount of boiler exhaust gas can be prevented in advance.

The wastewater treatment apparatus 1 described above includes a circulation path 7 that circulates boiler wastewater in the storage tank 4. The heat exchanger 9 and the ejector 11 are provided in the circulation path 7. These members may be provided in the drainage path 3. In this case, the cooling capacity of the heat exchanger 9 and the suction capacity of the ejector 11 can be set so that the boiler wastewater flowing into the storage tank 4 has a water temperature and pH that meet drainage standards. desirable. Further, when either the temperature of the boiler wastewater detected by the temperature sensor 24 or the pH of the boiler wastewater detected by the pH sensor 25 exceeds a predetermined value determined by the drainage standard, the storage tank 4 It is also possible to configure so that the boiler wastewater is returned to the drainage path 3 upstream of the heat exchanger 9 and the ejector 11.

It is a schematic explanatory drawing which shows the structure of one Example of the waste water treatment equipment which concerns on this invention.

1 waste water treatment apparatus 3 drainage path 7 circulation path 9 heat exchanger 11 Ezeku data

Claims (1)

A wastewater treatment apparatus comprising an ejector that sucks and mixes boiler exhaust gas into boiler wastewater and a heat exchanger that cools boiler wastewater,
Boiler drainage storage tank;
A circulation path for circulating boiler wastewater in the storage tank in which the ejector and the heat exchanger are arranged in series;
A neutralizer supply path for supplying boiler exhaust gas used for neutralization to the ejector;
A cooling water supply path for supplying cooling water used for cooling boiler drainage circulating through the circulation path to the heat exchanger;
A neutralizer supply valve and an air valve provided in the neutralizer supply path;
A cooling water supply valve provided in the cooling water supply path,
The neutralizer supply valve and the air valve are opened and closed based on the pH of the boiler waste water to switch between the boiler exhaust gas supply and the air suction to the ejector, and the cooling water supply valve is switched based on the water temperature of the boiler waste water. A wastewater treatment apparatus characterized in that it opens and closes and switches between supply and stop of cooling water to the heat exchanger .

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