JP2654893B2 - Method and apparatus for keeping heat and pressure in boiler during stop of combustion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for maintaining heat and pressure for maintaining a boiler at a predetermined temperature and pressure during combustion stoppage.

[0002]

2. Description of the Related Art Boilers are widely used from power generation to industrial use, as well as cooling / heating and commercial use, from large to medium or small or very small capacity type. In some cases, only one unit is installed in one plant. However, in many cases, two or more cans are installed to withstand as large a load fluctuation as possible, and the load of each boiler is adjusted according to the heat demand load. The number control is performed together with the control. In other words, if the heat demand increases, the individual boilers increase the amount of combustion from low combustion to high combustion, and if the heat demand further increases, the boilers that are not burning start firing one after another and feed into the steaming boiler system Will be done. On the other hand, when the heat demand decreased, the individual boilers controlled the load from high combustion to low combustion. On the other hand, when the heat demand further decreased, the number of boilers during combustion stopped one after another.

[0003] In this way, in normal operation, there is usually a boiler in which combustion is stopped and a boiler in combustion in the same series according to the heat load. In particular, if one large boiler stops and burns, that is, the operation and stop are repeated frequently, and if it is performed in a short time, a temperature difference occurs between the top and bottom of the boiler body, and the problem of thermal stress occurs. This can lead to severe accidents, such as cracks and leaks in the boiler body and others at extreme times. In addition, the boiler cools down as the time elapses after stopping the combustion. Has occurred.

[0004] On the other hand, from the boiler operator's side, the demand for heat from the boiler, such as steam from the boiler, hot water, or cold through an absorption refrigerator or the like, may increase at any time.
Therefore, even if the boiler demand is temporarily insufficient and the boiler shuts down, the pressure and temperature are reduced to a state close to the operating state so that the boiler whose combustion is stopped can be started immediately at any time. At present, we are always exposed to situations where we want to start up. In particular, this situation is not limited to the district heating / cooling boiler, but as an example, the demand load of the boiler varies depending on various situations where the unspecified number of supplied heat is used. For example, besides the temperature and humidity of the weather, changes in the work conditions of each company and the changes in the hot and cold heat demands on the south and north sides of the building. It is difficult to perform predictive control, such as predicting and starting the boiler first, and this cannot be done without relying on the conventional driver's intuition. When it is about to drop, the boiler that has stopped burning is constantly exposed to the demand to be started up as soon as possible and put into operation.

Therefore, for example, in the prior art, a boiler in which combustion is stopped is manually started once or twice a day and the pressure is raised to a predetermined pressure manually as a reference manual for the driver. When the pressure of the boiler drops to a predetermined pressure of 1 atm or 3 atm, the driver manually starts the combustion and raises the pressure to the predetermined pressure to maintain the pressure.
The boiler can be put into operation immediately because the steam load will be so much at this time of this season of this season based on many years of experience, and it will be ready for operation. -Based on the so-called qualitative method of starting combustion and keeping pressure and keeping warm, based on the judgment that it must be kept warm.
Therefore, the time required for starting and stopping the combustion for holding and warming the temperature varies, and sometimes it takes only 5 minutes, and sometimes it takes as long as 30 minutes. Was required.

Therefore, if possible, the stopped boiler is always or at least at a predetermined pressure and temperature, that is, in a so-called quantitative temperature state before restarting normal combustion. It is desired to automatically start the combustion after the state value of the stopped boiler is grasped and then start the combustion, and then hold the pressure and keep the temperature. Therefore, first of all, as a quantitative value, there is a problem as to when and in what state of the boiler during combustion stop the signal for starting and stopping the pressure holding / heating is issued, but until now, no good method or device has been found.

Further, even if the method or the device is found, the heating and pressurizing means to be started and stopped by the method and the device are, for example, as disclosed in Japanese Utility Model Laid-Open No. 2-302501 (1) Combustion. Steam from another boiler is directly blown into the stopped boiler to keep the temperature and pressure like an existing accumulator. 2) Return the hot air coming out of the exhaust gas outlet of the boiler whose combustion is stopped to the furnace to recover the exhaust heat and prevent the cooling of the entire boiler. 3) Blow water of the operating boiler is introduced from the bottom of the boiler whose combustion is stopped, and overflow is performed from the air release valve of the boiler.
By doing so, the exhaust heat of the blower water of the operating boiler is used to prevent the cooling of the boiler during stopping the combustion. 4) Each of the boilers is provided with a small-capacity burner for holding the pressure, and the boiler during combustion stop is operated from time to time to maintain the pressure of the boilers or keep them hot. 5) By communicating a portion of the operating boiler and the boiler whose combustion is stopped and a portion near the water surface below the water surface with the bottoms of the boilers, water circulation is generated between the boilers to keep the boiler stopped and warm. Press. 6) Steam or blow water from the operating boiler is supplied to a heat exchange pipe disposed below the water surface in the boiler body during which combustion is stopped, and the boiler water of the stopped boiler is heated to maintain heat and heat.
Hold pressure. 7) Steam or blow water from the operating boiler is supplied to a heat exchanger provided outside the boiler during which combustion is stopped, and the boiler water of the stopped boiler is heated by the heat exchanger to maintain heat and heat.
Hold pressure. 8) In the case of 7), particularly in a large water tube boiler, a two-phase flow containing air bubbles is sent out from the heat exchanger during rapid steaming to generate a water circulation in advance to keep the temperature and pressure. Etc.

[0008]

However, all of these methods and apparatuses have various problems. First, a measure of the state of the boiler when implementing means for heating and pressurizing for heat retention and pressure, may be called a signal for starting and stopping heating and pressurization for heat retention and pressure. However, it has not been proposed except for the steam pressure, and the pressure is not uniformly related to the heat distribution or temperature distribution inside the boiler. However, in the sense that it cannot be prevented by grasping only with steam pressure, it is, as it were, just a qualitative measure as described above, and it did not rely on conventional experience and intuition.

Next, in the means for keeping the temperature and the pressure, for example, in the above 1), it is difficult to blow the steam well so that the temperature of the entire boiler becomes uniform, and the blowing method is changed depending on the structure of the boiler. Need
Further, in the above 2), since the exhaust heat of the air that has entered the boiler is to be used, the boiler eventually cools down with time, and the effect of heating and pressurizing is large for a large device. Is less.

Further, in the above 3), it is usual that the exhaust heat of the blow water of the boiler alone is not enough for the heat quantity necessary for keeping the boiler warm with the same capacity, and only in very limited cases. Not only is it not available, but it also has the disadvantage that it cannot be started up immediately. That is, since the boiler in which the combustion is stopped is full of the blow water, the boiler water must be blown to the normal water level even when the start-up combustion is instructed. Therefore, it takes a considerable amount of time to start preparation while blowing. Further, in the above 4), a holding pressure burner is required separately.
The above 5) requires two upper and lower connecting pipes and a valve, and the above 6), 7) and 8) also require a heat exchanger tube and a heat exchanger, respectively. In such a case, it is not easy to use as a practical problem because there is no expensive equipment.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a method for stopping combustion at a low cost while maintaining the present normal use condition. Of the boiler scientifically, that is, qualitatively grasping the temperature of the boiler body, first heating, then grasping the steam pressure, increasing the pressure, and using them as conventional It is an object of the present invention to provide a method and an apparatus for heating and pressurizing in order to automatically maintain the temperature and pressure in a state of ordinary boiler equipment and without any trouble.

[0012]

In order to achieve the above object, the present invention provides a method and apparatus for holding and heating a boiler during a stop of combustion, the method comprising the steps of detecting a temperature from a temperature sensor installed near the bottom of the main body of the boiler. A signal and a signal from the steam pressure controller of the boiler are sent to a heating / pressurizing controller, and a heating / pressurizing start / stop signal from the heating / pressurizing controller is sent to a controller, The heating and pressurizing device is started and stopped by a controller to maintain the temperature and pressure of the boiler at predetermined values.

[0013]

[Action] The temperature and pressure of the boiler during combustion stop decrease with time, and when the temperature and pressure or the temperature decreases to a predetermined value, the heating / pressurizing device of each individual boiler or the standard equipment is provided. The burner is automatically operated for combustion, and automatically stopped when a predetermined temperature and pressure are reached, so that the temperature and pressure are automatically and safely maintained within a predetermined range.

[0014]

FIG. 1 shows an embodiment in which the present invention is applied to a boiler facility having a plurality of round boilers. FIG.
, 11 and 12 are boiler bodies in which a plurality of cans are arranged in parallel, and the main bodies 11 and 12 are respectively provided with main steam valves 21 and 22, main steam pipes 31 and 32 and a collecting pipe inlet / outlet valve 41. , 42 ... are provided. Reference numeral 5 denotes a collecting pipe connected to the collecting pipe inlet valves 41, 42,.
Is the main steam outlet pipe. Also, 71, 72 ... are steam pressure controllers of each boiler, and 81, 82 ... are burners of each boiler. The steam pressure regulators 71, 72,.
Also controls the steam pressure in the boiler,
The load is reduced and the steam pressure in the boiler is reduced.
Start up, the load becomes lighter and the steam pressure rises.
When it comes down, the burners 81, 82 ... are stopped appropriately and the boiler
The steam pressure is maintained at a desired pressure.

In the boiler equipment, during normal operation, the main steam valves 21, 22,... And the collecting pipe inlet / outlet valves 41, 42,.
Are fully open, but the heat demand load has dropped
When, for example, the boiler 11 is caused to stop burning by a signal from the steam pressure regulators 71, 72,..., The boiler 11 is stopped manually or automatically by a control panel 9 constituting a controller to be in a standby state. It is necessary to keep the boiler 11 warm and pressure.

In this case, for example, depending on whether it is determined that the stop of the boiler 11 may be continued for a while or whether the operation must be restarted immediately, it is determined whether the boiler 11 is stopped. In this case, the boiler 11 is kept warm so that the boiler 11 can be put under the normal operation system as soon as the demand for steam is generated.・ We have to keep the pressure and always prepare. At this time, the temperature and pressure of the boiler 11 decrease with the stop time due to the heat radiation, and accordingly, it is necessary to instruct the start of the heating / pressurizing combustion for keeping the temperature / pressure. Becomes

Accordingly, the boiler 1 in the case where the boiler 11 is in communication with another can and in the case where the boiler 11 is in a block state are described.
FIG. 2 shows the temperature change in the sample 1. That is, FIG. 2 shows, to the right, the positions of the temperature detectors mounted on the outer surface of the boiler can as a point below the water surface near the water surface (top), a center (middle), and a point near the bottom (bottom). The left side shows the temperature change at the measurement point. And (upper 1), (middle 1), (lower 1), (upper 2),
(Center 2) and (Bottom 2) show these positions.
The solid line in FIG. 2 indicates the state of the boiler in the “communication” state, and the broken line indicates the state of the “block”.

First, in the case of "communication", since the valves 21 and 41 in the normal operation state are kept fully open, the boiler 11 having stopped combustion restarts combustion and enters the operation line as it is. It is in. Therefore, when the boiler stops burning, its heat radiation starts and the temperature of the boiler water in the boiler starts to decrease, but the pressure is reduced to the value of the adjacent boiler 1.
2 is kept at a predetermined pressure, and eventually the latent heat of steam corresponding to the heat radiation is generated by the stop boiler 1.
1, the amount of steam condenses and accumulates in the boiler, and the water level rises accordingly. H2, H13, and H24 in the figure indicate the elapsed times of 2 hours, 13 hours, and 24 hours after the respective combustions are stopped.

Referring to FIG. 2, the situation (solid line A2) two hours after the stop of the combustion of "communication" will be described. The water surface is at NWL2, which is almost the same as NWL0 in normal use, and the surface temperature of the can body (water in the can) The temperature seems to be almost the same.)
Is on the line A2 close to the line A of the temperature Ts which has a certain difference in the saturation temperature with respect to the pressure at that time at the points (upper) and (middle), and from the line A at the point (lower). Is falling away. Similarly, in the situation 13 hours later (solid line A13), the water surface is higher than the initial position and is at NWL13, and the temperature at that point is considered to be on the A line corresponding to the above-mentioned temperature Ts, but is measured. In addition, the value (A13) at each point of (upper), (middle), and (lower) is significantly lower than that of the A line. Similarly, in the situation 24 hours later (solid line A24), the water surface is N
The temperature rises to WL24, and the temperature further decreases (upper), (middle), and (lower).

On the other hand, in FIG. 2, the boiler is a "block".
When the heat demand load is reduced, the boiler 1
1 to stop the boiler manually or automatically, and to stop the operation of the boiler, for example, because the operation of the stop boiler is not expected for a while, and to close the main steam valve 21 or the inlet valve 41 near the pipe of the boiler. It is. Therefore, in this case, since the boiler is disconnected from the normal operation system, the pressure of the boiler starts to decrease as the temperature decreases with the heat radiation, and the water surface maintains the original state. The state of this temperature change is indicated by broken lines B2, B13 and B24 in FIG.

As can be seen from FIG. 2, the difference between the temperature detected by the temperature detector at the (bottom) point of the boiler body in "communication" and "block" is different from those in the other (top) and (middle). The difference in (bottom) is 10 ° C. or less at most, and several degrees or less over time. The degree of temperature decrease with time is not so different between (upper) and (middle), and (lower) is significantly reduced.

It is appropriate that the temperature as a measure for keeping the boiler warm while the combustion is stopped is based on the difference from the temperature during normal operation of the boiler main body. The place where the difference is the largest is good, and at the point of (lower), as described above, "communication" after the same time has passed
The temperature difference between the "block" and the "block" is very small, and there is no special reason for distinguishing between the "communication" and the "block" in the automatic heating and pressurizing operation.

In view of the above, in the automatic heating and pressurizing operation for keeping the temperature and pressure of the boiler stopped during combustion, the temperature of the boiler can body which should be used as a guide for the automatic operation is detected. The points (lower) may be measured.
Therefore, as shown in FIG. 1, the temperature detection points of the boilers are set as points (lower 1), (lower 2)... Close to the bottom of each boiler, and a temperature detector is installed at these points, and the signals are heated and heated. Pressure regulator 10
1, 102 ..., and the heating and pressure from the heating and pressure controller
A pressurization start / stop signal is sent to the control panel 9 constituting the controller.

At this time, for example, the temperature at the point (lower 1) after the stop of combustion is two times lower than the temperature during normal operation (Ts or on the A line).
When the temperature drops by about 0 ° C to 30 ° C,
01 and the control panel 9 to automatically start and burn the stopped boiler to keep it warm, that the boiler has reached a predetermined temperature and that the steam pressure has reached a predetermined pressure. (Not necessary)
1 confirms that the control panel 9 stops the combustion.
If a stop signal is sent to the automatic heating / pressurizing device or the burner 81 via the control unit, the automatic heating / pressing operation for keeping the temperature / pressure of the boiler during the stop is almost 12 to 24. It will be done automatically once a time.

The control signals from the steam pressure regulators 71, 72... Used in normal automatic operation to the burners 81, 82. It is necessary to switch to the pressurizing regulators 101, 102,..., But the operation may be performed manually or automatically at any time in the control panel 9. Further, in the above embodiment, the case where a plurality of round boilers are installed has been described. However, the type of boiler may be a water can or a single boiler can be applied.

[0026]

According to the method and the apparatus for holding and maintaining the temperature of the boiler during the stop of the combustion according to the present invention, the temperature of the boiler during the stop of the combustion is remarkably changed by the temperature detector installed near the bottom of the main body of the boiler. The temperature is monitored quantitatively, heated by a predetermined temperature difference from the normal time, and furthermore, when the boiler is blocked, the heating is continued until the steam pressure rises to a predetermined value, and the temperature of the boiler in which combustion is stopped is stopped. Since the pressure and heat are maintained, the pressure and the temperature of the boiler can be reliably and automatically maintained at a low cost without changing the equipment of the conventional boiler, and the restart can be easily performed.

There is little fear of an unexpected problem that the boiler cannot keep up due to a sudden increase in the heat demand load, and the temperature and the temperature of the boiler are quantitatively and rationally monitored. Pressure is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic layout diagram of a boiler facility suitable for carrying out a pressure-holding / heating method according to the present invention.

FIG. 2 is a diagram illustrating a relationship between a temperature detection position of a boiler main body and a can body temperature.

[Explanation of symbols]

 11, 12 ... Boiler body 21, 22 ... Main steam valve 41, 42 ... Pipe inlet / outlet valve 71, 72 ... Steam pressure regulator 81, 82 ... Burner 9 Control panel 101, 102 ... Heating / pressure regulator Bottom 1, Bottom 2 ... Temperature detector installation position A2, A13, A24 Temperature condition when communicating B2, B13, B24 Temperature condition when blocking

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ryoji Takeyama 1-4-2 Marunouchi, Chiyoda-ku, Tokyo Inside Marunouchi Heat Supply Co., Ltd. (72) Inventor Hiroshi Kobayashi 1-9-36 shares in Oyodokita, Kita-ku, Osaka-shi (72) Inventor Hideshi Yamaguchi 1-9-36 Oyodo-kita, Kita-ku, Osaka-shi Inside Hirakawa-gai Dam Co., Ltd. (56) References JP-A-2-242011 (JP, A) JP-A-55-110802 ( JP, A) Hikaru 3-5006 (JP, U)

Claims (3)

(57) [Claims] 1. A method for maintaining the temperature of a blocked boiler during a combustion stoppage in a boiler facility having one or more cans.
In the pressure holding method, a signal from a temperature detector installed near the bottom of the main body of the boiler and a signal from a steam pressure controller of the boiler are sent to a heating / pressurizing controller, and the heating / pressurizing control is performed. Sends a heating / pressurization start / stop signal from the heater to the controller, and causes the controller to start / stop the heating / pressurization device to maintain the temperature and pressure of the boiler at predetermined values. Characteristic method of keeping heat and pressure of boiler during combustion stop. 2. Operation in a boiler facility in which a plurality of cans are installed.
In the method of keeping the temperature of a boiler stopped during combustion in communication with another can in a rotating state, a signal from a temperature detector installed near the bottom of the main body of the boiler is sent to a heating / pressurizing controller. Sending a heating start / stop signal from the heating / pressurizing controller to a controller, which causes the control unit to start / stop the heating device, thereby setting the temperature and pressure of the boiler to predetermined values. A method for keeping the temperature and pressure of the boiler during the stop of combustion, characterized by maintaining the temperature. 3. A temperature maintaining device for a boiler in which combustion is stopped in a boiler facility provided with a single can or a plurality of cans, wherein a temperature detector is installed near a bottom of a main body of the boiler. Connect the output of the heating / pressurizing regulator connected to the steam pressure regulator of the boiler to the controller, respectively.
An apparatus for keeping heat and pressure of a boiler stopped during combustion, wherein an output of the controller is connected to a burner and a main steam valve of the boiler.