JP4538799B2 - Neutralizer - Google Patents

Description

  The present invention relates to an apparatus for neutralizing alkaline boiler waste water with boiler exhaust gas.

  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. Further, if the operation of the steam boiler is continued, the can water is excessively concentrated to cause inconveniences such as carry-over. Therefore, a predetermined proportion of the can water is periodically added to the steam so as to maintain an appropriate can water concentration. It is necessary to discharge from the boiler. This operation is usually called concentration blow. Furthermore, after the steam boiler has been operated for a predetermined time, it is necessary to wash away all the can water in order to remove the so-called pot mud (sludge) that has settled at the bottom of the can body. This operation is usually called full blow.

  When discharging boiler drainage by concentration blow or full blow as described above, it is necessary to perform drainage treatment such as cooling and neutralization so as to conform to the drainage standards defined by the ordinance. As a method for neutralizing boiler wastewater, for example, there is a method in which acidic chemicals such as hydrochloric acid are added to boiler wastewater. However, in this method, handling of chemicals is dangerous. On the other hand, as a neutralization method that does not use chemicals, there is a method in which carbon dioxide gas is mixed into boiler wastewater, but since this method generally supplies carbon dioxide gas from a cylinder, management such as checking and replacing the remaining amount of the cylinder is complicated It is easy to become.

Therefore, Patent Document 1 discloses a neutralization device that performs neutralization using carbon dioxide contained in boiler exhaust gas instead of supplying carbon dioxide from a cylinder. In this neutralization apparatus, boiler exhaust gas from the steam boiler is sucked with a pump and mixed with boiler wastewater.
JP 2001-293484 A

  Here, when a plurality of the steam boilers are installed, not all of them are always in an operating state. When the steam boilers that are in combustion and are stopped are present among the steam boilers, the pump sucks boiler exhaust gas from the steam boiler that is burning, but from the steam boiler that is stopped, instead of boiler exhaust gas Aspirate air. For this reason, the carbon dioxide concentration in the boiler exhaust gas sucked by the pump fluctuates depending on the operation state of each steam boiler, and it is difficult to stably neutralize the boiler drainage.

  The problem to be solved by the present invention is to realize a neutralizing device capable of performing stable neutralization of boiler drainage.

  This invention was made in order to solve the said subject, and invention of Claim 1 is a neutralization apparatus provided with the suction mixing means to the boiler waste_water | drain of the boiler exhaust gas supplied from several boilers. Then, an exhaust gas stable supply valve is provided for each exhaust gas supply path of boiler exhaust gas from each boiler to the suction mixing means.

  In the first aspect of the present invention, the exhaust gas stable supply valves are opened and closed according to the operating state of the boilers. Specifically, the exhaust gas stable supply valve is opened when the boilers connected to the exhaust gas supply paths provided with the valves are in combustion, and closed when the boilers are stopped. Thereby, the said suction mixing means attracts | sucks only the boiler waste gas supplied from the boiler in combustion, and mixes this boiler waste gas with boiler waste_water | drain. On the other hand, the suction mixing means does not suck air from the stopped boiler.

  According to a second aspect of the present invention, in the first aspect, each of the exhaust gas stable supply valves is operated based on an operation signal from a boiler fuel supply valve of each of the corresponding boilers.

  In the invention according to claim 2, when the operation signal for opening the boiler fuel supply valve is the operation signal for opening the exhaust gas stable supply valve and closing the boiler fuel supply valve, The exhaust gas stable supply valve is closed. Thus, the suction mixing means sucks boiler exhaust gas from the burning boiler, but does not suck air from the stopped boiler.

  According to the first aspect of the present invention, the suction and mixing means is configured to be able to suppress the suction of air from the stopped boiler, so the carbon dioxide concentration in the boiler exhaust gas mixed into the boiler wastewater is stabilized. It can be made. As a result, stable boiler drainage can be neutralized.

  According to invention of Claim 2, since each said waste gas stable supply valve can be operated according to the driving | running state of each said boiler, the carbon dioxide gas concentration in the boiler waste gas mixed with boiler waste water is stabilized. be able to. As a result, stable boiler drainage can be neutralized.

Hereinafter, the best mode for carrying out the neutralization apparatus according to the present invention will be described.
The present invention is suitably implemented in a treatment apparatus that neutralizes alkaline boiler drainage from a plurality of steam boilers, so-called blow drainage, with carbon dioxide contained in boiler exhaust gas. That is, the boiler wastewater from each steam boiler is efficiently neutralized with carbon dioxide contained in the boiler exhaust gas to lower the pH, and discharged as treated water that meets the wastewater standards.

  The neutralization apparatus in this embodiment will be specifically described. The neutralization apparatus in this embodiment includes a drainage path through which boiler drainage from a plurality of steam boilers flows and an exhaust gas supply path for boiler exhaust gas used as a neutralizing agent for boiler drainage. Furthermore, a boiler mixing means for taking in boiler wastewater supplied from the drainage path, sucking boiler exhaust gas supplied from the exhaust gas supply path, and mixing them is provided. As the suction mixing means, for example, a pump capable of sucking and mixing two fluids, that is, a jet pump can be used. Further, as a more preferable suction mixing means, a means for sucking a gas by using a negative pressure generated by a fluid flow and mixing and discharging a liquid and a gas can be used. Examples of the mixing means include an ejector and an aspirator.

  In the neutralization device, boiler wastewater flowing through the drainage path is introduced into the suction mixing means. And in this suction mixing means, the boiler exhaust gas sucked from the exhaust gas supply path is mixed with the boiler waste water. As a result, the boiler exhaust gas dissolves while efficiently contacting the boiler waste water.

  Further, an exhaust gas stable supply valve is provided in each exhaust gas supply path of the boiler exhaust gas from each steam boiler to the suction mixing means.

  Each of the exhaust gas stable supply valves opens and closes according to the operating state of each of the steam boilers. Specifically, each of the stable exhaust gas supply valves is opened when the steam boiler connected to the exhaust gas supply path in which they are provided is burning, and closed when the steam boiler is stopped. Thereby, the said suction mixing means suck | inhales only the boiler waste gas supplied from the steam boiler in combustion, and mixes this boiler waste gas with boiler waste_water | drain. On the other hand, the suction mixing means does not suck air from the stopped steam boiler.

  Here, the opening / closing operation of the exhaust gas stable supply valve is performed based on, for example, an operation signal of the boiler fuel supply valve. That is, when the operation signal is for opening the boiler fuel supply valve, the exhaust gas stable supply valve is opened, and when the operation signal is for closing the boiler fuel supply valve, the exhaust gas stable supply valve is closed. State.

  As described above, according to the neutralization device of this embodiment, the suction mixing means does not suck air from the stopped steam boiler, so the carbon dioxide gas concentration in the boiler exhaust gas mixed into the boiler drainage Can be stabilized. As a result, stable boiler drainage can be neutralized.

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 neutralization apparatus for carrying out the present invention.
In FIG. 1, the neutralization apparatus 1 neutralizes the alkaline blow drainage (henceforth "boiler drainage") from the three steam boilers 2, 3, and 4 with the carbon dioxide gas contained in boiler exhaust gas, It is discharged as treated water that complies with wastewater standards.

  The neutralizing device 1 includes a drainage path 5 for supplying boiler drainage from the steam boilers 2, 3, 4, and a boiler drainage storage tank 6. Further, the neutralization device 1 includes exhaust gas supply paths 7, 8, and 9 for supplying boiler exhaust gas used for neutralization from the steam boilers 2, 3, and 4, respectively. That is, the exhaust gas supply path 7 supplies boiler exhaust gas from the steam boiler 2, the exhaust gas supply path 8 supplies boiler exhaust gas from the steam boiler 3, and the exhaust gas supply path 9 further includes the steam boiler. The boiler exhaust gas is supplied from 4.

  Each of the steam boilers 2, 3, and 4 includes an exhaust cylinder 10 that discharges exhaust gas obtained by burning fuel to the outdoors. The exhaust pipes 10 are connected to the exhaust gas supply paths 7, 8, and 9, respectively, so as to extract a part of the exhaust gas. The exhaust gas supply paths 7, 8, and 9 form a merging path (reference number omitted) on the downstream side, and the merging path is connected to an ejector described later.

  Exhaust gas stable supply valves 11, 12, and 13 are provided in the exhaust gas supply paths 7, 8, and 9, respectively. These exhaust gas stable supply valves 11, 12, and 13 are controlled to open and close in accordance with the operating states of the steam boilers 2, 3, and 4. Specifically, the exhaust gas stable supply valves 11, 12, and 13 are opened when the corresponding steam boilers 2, 3, and 4 are in combustion, and are closed when the steam boilers are stopped. Here, combustion and stop of each of the steam boilers 2, 3, and 4 are determined based on an operation signal of a boiler fuel supply valve (not shown) provided therein. That is, when the operation signal is to open any one of the boiler fuel supply valves, the corresponding one of the exhaust gas stable supply valves 11, 12, 13 is controlled to open. On the other hand, when the operation signal indicates that any one of the boiler fuel supply valves is closed, the corresponding one of the exhaust gas stable supply valves 11, 12, 13 is controlled to be closed.

  Both ends of a circulation path 14 for circulating the stored boiler drainage are connected to the storage tank 6, and a circulation pump 15, a cooling means 16, and an ejector 17 are connected to the circulation path 14 in order from the upstream side. Each is arranged in series.

  The cooling means 16 is a heat exchanger and includes a drain inlet 18 for supplying boiler drainage flowing through the circulation path 14 and a drain outlet 19 for discharging the cooled boiler drain. Further, the cooling means 16 includes a cooling water inlet 20 through which cooling water flows and a cooling water outlet 21 through which heat-exchanged cooling water is discharged. A cooling water supply path 22 is connected to the cooling water inlet 20, and a cooling water supply valve 23 is provided in the cooling water supply path 22.

  The ejector 17 has a drainage supply port 24 to which the circulation path 14 is connected and an exhaust gas suction port 25 to which the merging path is connected. The ejector 17 takes in boiler wastewater from the wastewater supply port 24, sucks boiler exhaust gas from the exhaust gas suction port 25, and mixes boiler wastewater and boiler exhaust gas. Boiler waste water mixed with boiler exhaust gas is injected into the storage tank 6 from the discharge port 26 of the ejector 17.

  Here, the boiler exhaust gas is supplied to the ejector 17 by opening / closing the exhaust gas supply valve 27 and the air valve 28 provided in the joining path of the exhaust gas supply paths 7, 8, 9, or the supply is stopped. (It will be explained in detail later).

  The storage tank 6 is provided with a temperature sensor 29 and a pH sensor 30 for detecting the water temperature and pH of the stored boiler drainage. The bottom of the storage tank 6 is connected to a neutralized and cooled boiler wastewater, that is, a treated water discharge path 31 for discharging treated water to the outside of the system. 32 is provided.

  The cooling water supply valve 23, the exhaust gas supply valve 27, the air valve 28 and the discharge valve 32 are based on signals input from the temperature sensor 29 and the pH sensor 30 to a control unit (not shown). Opening and closing is controlled by.

  Next, the operation of the neutralizing device 1 will be described. Boiler drainage from the steam boilers 2, 3, 4 is stored in the storage tank 6 through the drainage path 5. The stored boiler drainage circulates in the circulation path 14 by driving the circulation pump 15 based on a command from the control unit. The boiler wastewater is cooled and neutralized in the circulation path 14.

  First, the cooling of the boiler wastewater will be described in detail. The boiler wastewater flowing through the circulation path 14 is introduced from the drainage inlet 18 into the internal flow path (not shown) of the cooling means 16. When the cooling water supply valve 23 is opened in this state, the cooling water is supplied from the cooling water inlet 20 to the outside of the internal flow path via the cooling water supply path 22. This cooling water takes heat of the boiler drainage in the cooling means 16 and is discharged from the cooling water outlet 21. On the other hand, the cooled boiler drainage is discharged from the drainage outlet 19 to the circulation path 14 and recirculates into the storage tank 6.

  Next, neutralization of boiler wastewater will be specifically described. The boiler waste water flowing through the circulation path 14 is neutralized by the action of the ejector 17 by the boiler exhaust gas supplied from the exhaust gas supply paths 7, 8, 9. Specifically, the ejector 17 takes in boiler wastewater from the wastewater supply port 24 and sucks boiler exhaust gas supplied from the exhaust gas supply paths 7, 8, 9 from the exhaust gas suction port 25, And boiler exhaust gas. Thus, the boiler wastewater and the boiler exhaust gas are efficiently brought into contact with each other, and the boiler wastewater is stirred by the turbulent flow effect generated in the ejector 17, so that the boiler exhaust gas is dissolved and neutralized. And this boiler waste_water | drain is injected in the said storage tank 6 from the said discharge outlet 26. FIG. Here, the boiler exhaust gas that could not be dissolved in the boiler drainage in the ejector 17 is blown out into the storage tank 6 in the form of bubbles, and is refined and dissolved in the boiler drainage.

  By the way, in this embodiment, based on the water temperature of the boiler waste water detected by the temperature sensor 29, the cooling by the cooling means 16 is controlled by the control unit. Further, based on the pH of the boiler wastewater detected by the pH sensor 30, neutralization by the ejector 17 (that is, the suction mixing unit) is controlled by the control unit.

  First, the cooling control by the cooling means 16 will be specifically described. When the water temperature of the boiler waste water detected by the temperature sensor 29 exceeds a predetermined value determined by the waste water standard, the control unit opens the cooling water supply valve 23. As a result, the cooling water is supplied to the cooling means 16 via the cooling water supply path 22, and the boiler waste water is continuously cooled. On the other hand, when the water temperature of the boiler drain detected by the temperature sensor 29 becomes equal to or lower than a predetermined value determined by the drainage standard, the control unit closes the cooling water supply valve 23. As a result, the supply of the cooling water to the cooling means 16 is interrupted, and the cooling of the boiler drain is stopped.

  Next, the neutralization control by the ejector 17 will be specifically described. When the pH of the boiler wastewater detected by the pH sensor 30 exceeds a predetermined value determined by the wastewater standard, the control unit opens the exhaust gas supply valve 27 and closes the air valve 28. State. As a result, the ejector 17 can suck the boiler exhaust gas through the exhaust gas supply paths 7, 8, and 9, and the boiler waste water is continuously neutralized. On the other hand, when the pH of the boiler wastewater detected by the pH sensor 30 is equal to or lower than a predetermined value determined by the wastewater standard, the control unit closes the exhaust gas supply valve 27 and also sets the air valve 28. Is opened. As a result, outside air is sucked into the ejector 17, and neutralization of the boiler drainage is stopped. In this way, when outside air is sucked when boiler exhaust gas is not supplied, vibration caused by pressure fluctuations generated in the ejector 17 is suppressed.

  As described above, cooling control and neutralization control are performed individually until the boiler drainage in the storage tank 6 reaches the water temperature and pH determined by the drainage standard while circulating through the circulation path 14. . And when the boiler waste water in the said storage tank 6 becomes the water temperature and pH suitable for drainage standards, the said control part will open the said discharge valve 32, and will discharge boiler waste water via the said treated water discharge path 31. Discharge out of the system.

  Here, the exhaust gas stable supply valves 11, 12, 13 perform opening / closing operations in accordance with the operating states of the steam boilers 2, 3, 4. Specifically, each of the exhaust gas stable supply valves 11, 12, and 13 is combusting the steam boilers 2, 3, and 4 at the connection source of the exhaust gas supply paths 7, 8, and 9 in which these valves are provided. When open, each opens and closes when stopped. That is, the exhaust gas stable supply valve 11 is controlled to open and close in accordance with the operating state of the steam boiler 2, and the exhaust gas stable supply valve 12 is controlled to open and close in accordance with the operating state of the steam boiler 3, and further the exhaust gas The stable supply valve 13 is controlled to open and close in accordance with the operation state of the steam boiler 4. Thereby, the ejector 17 sucks the boiler exhaust gas supplied from the steam boilers 2, 3, 4 during combustion, and mixes the boiler exhaust gas into the boiler drainage. On the other hand, the ejector 17 does not suck air from the steam boilers 2, 3, and 4 that are stopped.

  The opening and closing operation of each of the exhaust gas stable supply valves 11, 12, 13 is performed based on the operation signal of the boiler fuel supply valve. That is, when the operation signal is to open any one of the boiler fuel supply valves, the corresponding one of the exhaust gas stable supply valves 11, 12, 13 is opened, and the boiler fuel supply is performed. In the case of an operation signal for closing one of the valves, one of the corresponding exhaust gas stable supply valves 11, 12, 13 is closed. Thereby, the ejector 17 selectively sucks boiler exhaust gas from the steam boilers 2, 3, and 4 during combustion. On the other hand, the ejector 17 does not suck air from the steam boilers 2, 3, and 4 that are stopped.

  Although the said neutralization apparatus 1 in this Example has provided the said cooling means 16 and the said ejector 17 in the said circulation path | route 14, this invention is not limited to this. For example, the cooling means 16 may be provided in the drainage path 5.

  Moreover, although the said neutralization apparatus 1 has connected the said confluence | merging path | route to the said ejector 17, you may connect to the said ejector 17 separately, without making each said waste gas supply path | route 7, 8, 9 merge. . That is, the ejector 17 having a plurality of the exhaust gas suction ports 25 can be used. A plurality of ejectors 17 may be provided according to the number of the exhaust gas supply paths 7, 8, 9.

It is a schematic explanatory drawing which shows the structure of one Example of the neutralization apparatus which concerns on this invention.

Explanation of symbols

1 Neutralizer 2, 3, 4 Steam boiler (boiler)
11, 12, 13 Exhaust gas stable supply valve 17 Ejector (suction mixing means)

Claims (2)

It is a neutralization device equipped with suction mixing means to boiler wastewater of boiler exhaust gas supplied from a plurality of boilers,
A neutralizing apparatus, wherein an exhaust gas stable supply valve is provided for each exhaust gas supply path of boiler exhaust gas from each boiler to the suction mixing means.   2. The neutralization device according to claim 1, wherein each of the exhaust gas stable supply valves is operated based on an operation signal of a boiler fuel supply valve of each of the corresponding boilers.

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