JP6146270B2 - Boiler system - Google Patents

Description

  The present invention relates to a boiler system. More specifically, the present invention relates to a closed type boiler system that collects drain discharged from a load device without supplying it to the atmosphere and supplies water to the boiler.

  Conventionally, steam generated by a boiler is supplied to the load equipment, and the drain generated by condensation of the steam used as a heat source in the load equipment is collected in a sealed drain tank with pressure resistance at high temperature and pressure. And the closed type boiler system which supplies water to a boiler again is proposed (for example, refer patent document 1).

JP 2006-105442 A

  By the way, in a boiler system, when a combustion instruction is issued to a boiler that has stopped combustion, first, after supplying water to a can body that generates steam to a predetermined water level, combustion of the boiler is started (below) Water supply performed before the start of combustion is also referred to as initial water supply). Here, in the closed type boiler system, a high-temperature and high-pressure drain is used as water supply. Therefore, when low-temperature water (can water) remains in the boiler body that has been instructed to burn, the remaining can water is heated by the supplied high-temperature and high-pressure drain and boiled vigorously. Vibration will occur in the can body. And if vibration occurs in the can body, there is a risk of damage to parts and piping constituting the boiler, and anxiety is given to the user of the boiler.

  Accordingly, an object of the present invention is to provide a closed-type boiler system capable of suppressing the occurrence of vibrations in the can body due to boiling of the can water during initial water supply.

  The present invention relates to a closed-type boiler system that uses drainage generated from generated steam as feed water again, and a boiler having a can body that generates steam and a feed water heater that heats the feed water supplied to the can body. A drain tank for storing drain produced by condensing steam generated in the boiler and used in load equipment; a drain supply line for connecting the drain tank and the boiler and supplying drain to the boiler as feed water; A water supply valve provided in the drain supply line for adjusting a flow rate of the drain supplied to the boiler, and an initial water supply stage of the boiler, wherein the water supply valve is opened at a first opening to the can body. A controller for supplying water, wherein the controller is configured such that, in the initial water supply stage, the water supply temperature at the inlet of the can body is equal to or higher than a first temperature, When the feed water temperature at the inlet of the boiler is equal to or higher than a second temperature higher than the first temperature, the opening of the water supply valve is set to a second opening smaller than the first opening. It relates to the boiler system to be changed.

  Further, when the opening of the water supply valve is changed from the first opening to the second opening, the control unit closes the water supply valve and then sets the second opening. Is preferred.

  Moreover, it is preferable that the said control part returns the opening degree of the said water supply valve to a 1st opening degree, when the temperature of the said can body exceeds 3rd temperature.

  Moreover, it is preferable that the said control part determines with the said initial stage water supply stage if the water level of the said can is below a 1st water level when there is a combustion instruction | indication in the said boiler.

  According to the boiler system of the present invention, it is possible to suppress the occurrence of vibrations in the can body due to boiling of the can water during initial water supply.

It is a figure showing the composition of the boiler system concerning one embodiment of the present invention. It is the figure which showed typically the boiler which comprises a boiler system. It is a functional block diagram which shows the structure of the control part of the boiler system of this invention.

Hereinafter, a preferred embodiment of a boiler system of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a boiler system 1 according to an embodiment of the present invention.
The boiler system 1 of this embodiment is provided with the boiler apparatus 70 comprised including the some boiler 10 and the closed-type drain collection | recovery apparatus 20 as shown in FIG.

  As shown in FIG. 1, the boiler device 70 includes a plurality of boilers 10, a steam header 71 in which steam generated by the plurality of boilers 10 is gathered, and a connecting pipe that connects the plurality of boilers 10 and the steam header 71. 72.

The boiler 10 generates steam by heating the feed water supplied to the inside with combustion gas. In the present embodiment, the boiler 10 is supplied with the drain recovered by a drain recovery device 20 described later as feed water.
Details of the boiler 10 will be described later.

As shown in FIG. 1, the steam generated by the plurality of boilers 10 is supplied to the steam header 71 through a connecting pipe 72. The steam header 71 stores the steam generated by the plurality of boilers 10 and supplies the steam to the load device 50.
The load device 50 uses the steam generated in the boiler 10 as a heat source, and performs heat exchange with the object to be heated.

The drain recovery device 20 recovers the drain produced by agglomeration of the steam generated by the boiler 10 in the load device 50 in a high temperature and high pressure state, and supplies the recovered drain to the boiler 10 again as feed water. To do.
The drain recovery device 20 includes a drain tank 21, an open tank 22, a first steam supply line L1, a drain recovery line L2, a drain supply line L3, a second steam supply line L4, and a flash steam discharge line L5. And a makeup water supply line L6.

  The drain tank 21 collects and stores the drain generated by agglomeration of part of the steam used for heat exchange in the load device 50. The drain tank 21 is constituted by a pressure vessel that has pressure resistance and can be sealed.

  The open tank 22 is open to the atmosphere. The open tank 22 stores makeup water supplied to the boiler 10. Further, the open tank 22 is introduced with flash steam generated from the drain in the drain tank 21.

The first steam supply line L1 connects the steam header 71 and the load device 50 and supplies the steam generated by the boiler 10 to the load device 50.
The drain collection line L <b> 2 connects the load device 50 and the drain tank 21, and collects the drain generated in the load device 50 in the drain tank 21. A steam trap 61, a check valve 62, and a motor valve 63 that discharge drain generated in the load device 50 and prevent discharge of steam are disposed in the drain recovery line L2.

  The drain supply line L3 connects the drain tank 21 and the boiler 10, and supplies the drain accommodated in the drain tank 21 to the boiler 10. In the present embodiment, the upstream end of the drain supply line L <b> 3 is connected to the lower portion of the drain tank 21. Further, the downstream side of the drain supply line L <b> 3 branches so as to be connected to each of the plurality of boilers 10.

  A drain pump 64 and a water supply valve 65 are disposed in the drain supply line L3. The drain pump 64 boosts the drain supplied from the drain tank 21 and supplies it to the boiler 10. The water supply valve 65 is constituted by a motor valve and adjusts the flow rate of the drain supplied from the drain tank 21 to the boiler 10. Further, temperature sensors 31 and 32 for measuring the temperature of the drain flowing in the drain supply line L3 are respectively provided at the inlet of the boiler 10 (the inlet of the feed water heater 19 described later) and the inlet of the can body 11 described later in the drain supply line L3. Is arranged (see FIG. 2).

  The second steam supply line L4 connects the steam header 71 and the drain tank 21. The second steam supply line L <b> 4 supplies steam generated in the boiler 10 to the drain tank 21 and adjusts the pressure inside the drain tank 21. A pressure adjustment valve 66 and a motor valve 67 are disposed in the second steam supply line L4.

  The flash steam discharge line L5 connects the drain tank 21 and the open tank 22, and discharges the flash steam generated in the drain tank 21 to the open tank 22. A pressure regulating valve 68 is disposed in the flash steam discharge line L5. When the pressure inside the drain tank 21 exceeds a predetermined pressure, the pressure regulating valve 68 releases the flash vapor to the open tank 22 side and reduces the pressure inside the drain tank 21.

  The makeup water supply line L <b> 6 connects the open tank 22 and the drain tank 21, and supplies water stored in the open tank 22 to the drain tank 21. A pump 69 is disposed in the makeup water supply line L6.

Next, the configuration of the boiler 10 will be described. FIG. 2 is a diagram schematically illustrating the configuration of the boiler 10.
As shown in FIG. 2, the boiler 10 includes a can 11, a water level measuring unit 111 and a can temperature measuring unit 112 provided in the can 11, an air supply duct 16, an exhaust duct 18, and a water heater. 19 and a control unit 90.
The can 11 includes a lower header, a plurality of water pipes, and an upper header (all not shown). In the can 11, water supplied from the lower header to the plurality of water pipes (drain) is heated to generate steam, and the generated steam is collected in the upper header. The steam generated in the can 11 is supplied from the upper header to the steam header 71 through the connecting pipe 72.
The water level measuring unit 111 measures the water level of the can body 11 (a plurality of water pipes). The can body temperature measurement unit 112 measures the temperature of the can body 11 (more specifically, the temperature of the water pipe disposed inside the can body 11).

  The air supply duct 16 supplies combustion air and fuel gas to the can body 11. More specifically, a fuel supply line 161 to which fuel gas is supplied and a blower 162 to which combustion air is supplied are connected to the upstream side of the air supply duct 16. The air supply duct 16 mixes the fuel gas supplied from the fuel supply line 161 and the combustion air supplied from the blower 162 and supplies the mixture to the can 11.

The exhaust duct 18 discharges the combustion gas generated by burning the mixed gas inside the can 11.
The feed water heater 19 is disposed in the exhaust duct 18 and performs heat exchange between the combustion gas discharged from the can body 11 and the drain supplied to the can body 11. That is, in the present embodiment, the drain supply line L <b> 3 is connected to the can body 11 after passing through the feed water heater 19 disposed in the exhaust duct 18.

  The controller 90 performs control of the combustion state of the boiler 10 and control of water supply to the boiler 10. Details of the water supply control by the control unit 90 will be described later.

Next, operation | movement of the boiler system 1 of this embodiment is demonstrated.
In the present embodiment, first, steam is generated in the boiler 10. Specifically, first, the fuel gas and the combustion air are mixed in the air supply duct 16, and the mixed gas of the fuel gas and the combustion air is jetted into the can 11 and burned. Next, the drain supplied to the can 11 is heated by the combustion gas generated by the combustion of the mixed gas to generate steam. The steam generated in the can 11 is supplied to the steam header 71 via the connecting pipe 72.
The steam supplied to the steam header 71 becomes drain after being used in the load device 50 and is stored in the drain tank 21 in a high temperature and high pressure state. The drain stored in the drain tank 21 is supplied as feed water to the boiler 10 through the drain supply line L3.

  On the other hand, the combustion gas used for generating steam inside the can 11 is discharged outside through the exhaust duct 18. Here, in this embodiment, the feed water heater 19 is disposed in the exhaust duct 18, and the drain supply line L <b> 3 is connected to the boiler 10 (lower header 14) after passing through the feed water heater 19. Thereby, the drain which distribute | circulates the drain supply line L3 is heated in the feed water heater 19, and is supplied to the boiler 10. FIG.

Here, in the boiler system 1 of the present embodiment, the control unit 90 includes the water supply valve 65 so that the water level of the boiler 10 measured by the water level measurement unit 111 becomes a target water level set in advance according to the combustion state. Is adjusted to control the flow rate of the drain supplied to the boiler 10.
Moreover, the control part 90 performs the initial water supply control different from the water supply control of a combustion state, when burning the boiler 10 which has stopped combustion.

  Specifically, as shown in FIG. 3, the control unit 90 has an initial water supply stage determination unit 91, a water supply valve control unit 92, and a can inlet temperature determination unit 93 as a configuration for executing the initial water supply control. And a boiler inlet temperature determination unit 94 and a can body temperature determination unit 95.

The initial water supply stage determination unit 91 determines whether or not the boiler 10 is in the initial water supply stage when the boiler 10 that has stopped combustion is burned. In the present embodiment, the initial water supply stage determination unit 91 determines whether or not the water level of the boiler 10 is equal to or lower than a preset first water level, and when the water level of the boiler 10 is equal to or lower than the first water level, It is determined that the boiler 10 is in the initial water supply stage.
The first water level is set as a water level higher than the upper limit value of the target water level in the combustion state, for example.

  When the initial water supply stage determination unit 91 determines that the boiler 10 is in the initial water supply stage, the water supply valve control unit 92 opens the water supply valve 65 at the first opening and supplies the can body 11 with initial water supply. Let it be done. Here, the first opening is set larger than the maximum opening of the water supply valve 65 in the combustion state, for example. Thereby, since water can be supplied to the boiler 10 in a short time in the initial water supply stage, the time until the start of combustion of the boiler 10 which has stopped combustion can be shortened.

  Here, in the closed type boiler system, a high-temperature and high-pressure drain is used as water supply. Therefore, when low-temperature water (can water) remains in the can 11 of the boiler 10 that has stopped combustion, the remaining can water is heated by the high-temperature and high-pressure drain supplied and boils violently. And vibration will generate | occur | produce in the can 11. And when a vibration generate | occur | produces in the can body 11, there exists a possibility that damage may arise in the components and piping which comprise the boiler 10. FIG.

  Therefore, in the present embodiment, in the initial water supply stage, when the temperature of the drain flowing through the drain supply line L3 satisfies a predetermined condition, the opening of the water supply valve 65 is reduced to reduce the amount of drain supplied to the can body 11. The flow rate is reduced, and the occurrence of vibration in the can 11 is suppressed. Specifically, the water supply valve control unit 92, the can body inlet temperature determination unit 93, the boiler inlet temperature determination unit 94, and the can body temperature determination unit 95 perform the following control.

The can body inlet temperature determination unit 93 determines whether or not the drain temperature (water supply temperature) at the inlet of the can body 11 measured by the temperature sensor 32 is equal to or higher than the first temperature.
The boiler inlet temperature determination unit 94 determines whether or not the temperature of the drain at the inlet of the boiler 10 measured by the temperature sensor 31 is equal to or higher than a second temperature higher than the first temperature.
Here, the first temperature can be set to a temperature (for example, 60 ° C. to 80 ° C.) lower by a predetermined temperature than 100 ° C. which is the saturation temperature of water at atmospheric pressure. Moreover, 2nd temperature can be set to 100 degreeC which is the saturation temperature of the water in atmospheric pressure, for example.

The water supply valve control unit 92 determines that the temperature of the drain at the inlet of the can body 11 is equal to or higher than the first temperature (for example, 60 ° C. to 80 ° C.) by the can body inlet temperature determination unit 93 and the boiler inlet When it is determined by the temperature determination unit 94 that the temperature of the drain at the inlet of the boiler 10 is equal to or higher than the second temperature (for example, 100 ° C.), the opening degree of the water supply valve 65 is set to be smaller than the first opening degree. Change the opening to 2.
Thereby, in the initial water supply stage, when the temperature of the water supply (drain) supplied to the can body 11 is high, the amount of water supplied to the can body 11 can be reduced, so that the can water remaining in the can body 11 can be reduced. Can be prevented from boiling violently.

That is, even when the water supply temperature at the inlet of the can 11 is relatively low when the initial water supply is started (that is, from the first temperature to the second temperature), the water supply temperature at the inlet of the boiler 10 is high (that is, When the temperature is equal to or higher than the second temperature), the water supply temperature rapidly increases thereafter.
On the other hand, even if the feed water temperature at the inlet of the can body 11 has reached the first temperature, if the feed water temperature at the inlet of the boiler 10 is equal to or lower than the second temperature, the temperature at the inlet of the can body 11 exceeds the second temperature. The can water remaining in the can 11 does not boil violently.

  Therefore, when the temperature of the drain at the inlet of the can 11 is equal to or higher than the first temperature and the temperature of the drain at the inlet of the boiler 10 is equal to or higher than the second temperature, the amount of water supplied to the can 11 is reduced. Thus, it is possible to effectively prevent the can water remaining in the can body 11 from boiling violently without reducing the amount of water supply unnecessarily.

  Moreover, when changing the opening degree of the water supply valve 65 from a 1st opening degree to a 2nd opening degree, the water supply valve control part 92 is good also as a 2nd opening degree after closing a water supply valve once. Thereby, the error which generate | occur | produces by the opening degree change of the water supply valve 65 can be eliminated by making the water supply valve 65 into a closed (full-closed) state once.

  The can body temperature determination unit 95 determines whether or not the temperature of the can body 11 measured by the can body temperature measurement unit 112 exceeds the third temperature. Here, the third temperature can be set to 100 ° C., which is the saturation temperature of water at atmospheric pressure, for example.

  And the water supply valve control part 92 returns the opening degree of the water supply valve 65 to a 1st opening degree, when the can body temperature determination part 95 determines with the temperature of the can body 11 having exceeded 3rd temperature. That is, when the temperature of the can body 11 (that is, the temperature of the can water) reaches a predetermined temperature (for example, 100 degrees), the can water boils violently even if high temperature drain is supplied to the can body 11. Never do. Therefore, when the temperature of the can body 11 exceeds the third temperature, the can body 11 is warmed by returning the opening of the water supply valve 65 to the first opening, and there is no risk of boiling of the can water. Can quickly increase the water supply.

  According to the boiler system 1 of this embodiment demonstrated above, there exist the following effects.

(1) Even when the water supply temperature at the inlet of the can 11 is relatively low when the initial water supply is started (that is, from the first temperature to the second temperature), the water supply temperature at the inlet of the boiler 10 is high ( That is, when the temperature is equal to or higher than the second temperature, the water supply temperature rapidly increases thereafter. On the other hand, even if the feed water temperature at the inlet of the can body 11 has reached the first temperature, if the feed water temperature at the inlet of the boiler 10 is equal to or lower than the second temperature, the temperature at the inlet of the can body 11 exceeds the second temperature. The can water remaining in the can 11 does not boil violently.
Therefore, when the water supply temperature at the inlet of the can body 11 is equal to or higher than the first temperature and the water supply temperature at the inlet of the boiler 10 is equal to or higher than the second temperature in the initial water supply stage, the control unit 90 The opening was changed from the first opening to the second opening. Thereby, in the initial water supply stage, the amount of water supplied to the can body 11 can be reduced at an appropriate timing, so that the can water remaining in the can body 11 can be effectively prevented from boiling violently. Therefore, it can suppress that a vibration generate | occur | produces in the can 11 at the time of initial water supply.

  (2) When the water supply valve 65 is constituted by a motor valve, an error occurs when the opening degree of the valve is changed. Therefore, when the opening degree of the water supply valve 65 is changed from the first opening degree to the second opening degree, the water supply valve 65 is once closed and then opened at the second opening degree. Thereby, the error which generate | occur | produces by the opening degree change of the water supply valve 65 can be eliminated by making the water supply valve 65 into a closed (full-closed) state once. Therefore, the flow rate control of the water supply in the initial water supply stage can be performed more accurately.

  (3) When the temperature of the can body 11 (that is, the temperature of the can water) reaches a predetermined temperature (for example, the saturation temperature of water at the internal pressure of the can body 11), high temperature drain is applied to the can body 11. Even if supplied, canned water does not boil violently. Therefore, when the temperature of the can 11 exceeds the third temperature, the opening degree of the water supply valve 65 is returned to the first opening degree. Thereby, when the can body 11 is warmed and there is no fear of boiling of the can water, the amount of water supply can be quickly increased. Therefore, the time required for the initial water supply stage can be shortened while preventing the vibration of the can 11.

  (4) When the boiler 10 that has stopped combustion is burned, the initial water supply stage determination unit 91 determines that the water level of the can 11 is equal to or lower than the first water level. Thereby, it can determine correctly that the boiler 10 exists in an initial stage water supply stage.

The preferred embodiment of the boiler system 1 of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and can be modified as appropriate.
For example, in this embodiment, although the boiler system 1 was comprised including the some boiler 10, it is not restricted to this. That is, you may comprise a boiler system by one boiler.

1 Boiler System 10 Boiler 11 Can 19 Water Feed Heater 21 Drain Tank 65 Water Supply Valve 90 Control Unit L3 Drain Supply Line

Claims (4)

It is a closed type boiler system that uses drainage generated from the generated steam again as feed water,
A boiler having a can body for generating steam and a feed water heater for heating feed water supplied to the can body;
A drain tank for storing drain produced by condensation of steam generated in the boiler and used in the load device;
A drain supply line for connecting the drain tank and the boiler and supplying drain to the boiler as feed water;
A water supply valve that is provided in the drain supply line and adjusts the flow rate of the drain supplied to the boiler;
In the initial water supply stage of the boiler, a controller that opens the water supply valve at a first opening and supplies water to the can body, and
In the initial water supply stage, the control unit is configured such that the water supply temperature at the inlet of the can body is equal to or higher than a first temperature, and the water supply temperature at the inlet of the boiler is equal to or higher than a second temperature higher than the first temperature. And a boiler system that changes the opening of the water supply valve to a second opening smaller than the first opening.   The said control part makes the said 2nd opening after closing the said water supply valve once, when changing the opening of the said water supply valve from the said 1st opening to the said 2nd opening. The boiler system described in   The boiler system according to claim 1 or 2, wherein when the temperature of the can body exceeds a third temperature, the control unit returns the opening degree of the water supply valve to the first opening degree.   The boiler according to any one of claims 1 to 3, wherein the controller determines that the initial water supply stage is the water level when the water level of the can body is equal to or lower than the first water level when the boiler is instructed to burn. system.

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