JPH06174204A - Method and device for maintaining temperature and pressure of boiler during suspension of combustion - Google Patents

Abstract

(57) [Summary] [Purpose] The boiler is in a normal operating condition and at a low cost, the boiler condition is qualitatively grasped to determine the temperature of the boiler itself, and then the steam pressure is increased. In order to grasp and boost the pressure, and to keep them in the conventional boiler equipment without adding a special device, and to automatically keep them in a heat-retaining / pressure-retaining state without human intervention. It is intended to provide a method of heating and pressurizing and a device thereof. [Structure] In a method of keeping heat and pressure of a blocked boiler in which combustion is stopped in a boiler facility in which a single can or a plurality of cans are installed, a temperature detector installed at a lower portion 1, a lower portion 2, ... Near a bottom portion of a main body of the boiler. The signals from the steam pressure regulators 71, 72 ...
1, 102 ..., The heating / pressurizing start / stop signal from the heating / pressurizing controller is sent to the controller 9, and the controller starts / stops the heating / pressurizing device. In addition, a method and an apparatus for keeping the temperature and pressure of the boiler during combustion stopped so that the temperature and pressure of the boiler are maintained at predetermined values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat retention / pressure retention method and apparatus for maintaining a boiler at a predetermined temperature and pressure while combustion is stopped.

[0002]

2. Description of the Related Art Boilers are widely used for power generation, industrial purposes, as well as for heating and cooling purposes and commercial purposes, from large-sized to medium-sized to ultra-small capacity type. Although only one unit may be installed in one plant, many are equipped with multiple cans of two or more units to withstand large load fluctuations as widely as possible, and the load of each boiler depends on the heat demand load. The number of units is controlled together with the control. That is, if the heat demand increases, the combustion amount of each boiler increases from low combustion to high combustion, and if the heat demand further increases, the boilers that have stopped combustion will start start-up combustion one after another and feed them into the steaming boiler system. Will be done. On the other hand, on the contrary, when the heat demand decreased, the load control was performed for each boiler from high combustion to low combustion, and when it further decreased, the burning boilers were stopped one after another.

As described above, in normal operation, there are usually a boiler that stops combustion and a boiler that is burning in the same series depending on its heat load. And, in particular, when a large boiler is stopped and burned frequently, that is, when the operation and stop are frequently repeated, or even if it is performed in a short time, a temperature difference occurs between the upper and lower parts of the boiler body, which causes a problem of thermal stress. If it happens or there is a difference in expansion, it will lead to a serious accident that cracks and leaks will occur in the boiler body and other parts at extreme times. In addition, the boiler gets colder after a long time after the combustion is stopped, but if it is burned suddenly with a cold boiler, combustion failure will occur in the boiler, and in the worst case, a gas explosion will actually occur. Has occurred.

On the other hand, from the viewpoint of the boiler driver, the heat demand of the destination such as steam or hot water from the boiler or cold heat from the absorption refrigerator may increase at any time.
Therefore, even if the boiler demand stops temporarily due to insufficient heat demand, the pressure and temperature of the boiler can be brought up to a state close to its operating state so that the boiler whose combustion is stopped can be immediately started up. The current situation is that we are always exposed to the situation that we want to launch it. In particular, this situation is not limited to the district heating and cooling boiler, but to explain the example, the demand load of the boiler varies depending on various situations of the use destination of the unspecified number of individual heat supplies. For example, in addition to the temperature and humidity of the weather, the change in work conditions of each company and the demand for warm and cold heat on the south and north faces of the building, in other words, from the boiler driver's side, that heat demand can be calculated in advance. It is difficult to perform predictive control, such as predicting and starting the boiler first, and it can only be done by the conventional driver's intuition, so for example, the heat demand suddenly increases and the pressure of the supply steam increases. If the fuel consumption is about to drop, it means that the boiler that has stopped combustion is always being exposed to the requirement to start it up as soon as possible and put it into the operation sequence.

Therefore, for example, conventionally, a boiler in which combustion is stopped has a manual manual start-up combustion once or twice a day to raise the pressure to a predetermined pressure, or the combustion is stopped. When the boiler pressure drops to a predetermined pressure such as 1 atm or 3 atm, the driver manually starts combustion to raise the pressure to a predetermined pressure to maintain the pressure.
The boiler is kept warm so that it can be stopped again and put into standby, or because of many years of experience, the steam load will be so much at this time during this time of the season.・ The so-called qualitative method was used, in which it was started and burned to keep the pressure and keep it warm when it was necessary to keep it warm.
Therefore, the time required to start and stop combustion for keeping the pressure and heat is variable, and it may take 5 minutes for one time or 30 minutes for one time. Was required.

Therefore, if possible, it is preferable that the stopped boiler is always or at least placed in a certain quantitative temperature state of a predetermined pressure and temperature before resuming normal combustion. It is desirable to keep the pressure and heat after starting and combusting automatically after grasping the state value of the boiler which is stopped. So, first of all, as a quantitative value, it becomes a problem when and when the state of the boiler when combustion is stopped and when the signal to start / stop the holding pressure / heating is issued, but until then, no good method or device was found.

Further, even if the method or apparatus is found, the heating / pressurizing means to be stopped by the method is, for example, 1) combustion as disclosed in Japanese Utility Model Laid-Open No. 3025021/1990. Steam from other boilers is blown directly into the stopped boiler to keep it warm and pressure like an existing accumulator. 2) The hot air that emerges from the exhaust gas outlet of the boiler that is in the combustion stopped state is returned to the inside of the furnace to recover the exhaust heat, and at the same time, the cooling of the entire boiler is prevented. 3) Put the blower water of the boiler in operation from the bottom of the boiler in which combustion is stopped and put it into the overflow from the air vent valve of the boiler.
By doing so, the exhaust heat of the blower water of the operating boiler is used to prevent cooling of the boiler when combustion is stopped. 4) A small-capacity burner is attached to each boiler to maintain the pressure, and the boiler whose combustion is stopped is operated occasionally to maintain the pressure of the boiler or keep it in a warm state. 5) Keeping the stopped boiler warm by keeping the bottom of both boilers in communication with the bottom of the boiler, which is close to the water surface, between the boiler in operation and the boiler in combustion stop. Press. 6) The steam or blower water from the boiler in operation is supplied to the heat exchange pipe arranged below the water surface in the boiler main body in the combustion stop, and the boiler water in the boiler in the stop is heated to keep heat.
Hold the pressure. 7) Steam or blower water from the boiler in operation is supplied to a heat exchanger provided outside the boiler in combustion stop, and the boiler water in the boiler in stop is heated by the heat exchanger to keep heat.
Hold the pressure. 8) In the above 7), particularly in a large-sized water tube boiler, when rapidly evaporating, a two-phase flow containing bubbles is sent out from the heat exchanger to cause water circulation in advance to keep the temperature and pressure. Etc.

[0008]

However, all of these methods, devices and other means have various problems. First, the standard of the state of the boiler when implementing means for heating / pressurizing for heat retention / pressure retention, which may be called a signal to start / stop heating / pressurization for heat retention / pressure retention However, it has not been proposed in addition to the steam pressure, and the pressure is not in a uniform relationship with the heat distribution or temperature distribution inside the boiler, and there is a problem due to distortion of thermal stress at the time of starting the boiler. In the sense that it can't be prevented by knowing only by steam pressure, it is, so to speak, just a qualitative guideline as described above, and it was beyond the scope of relying on conventional experience and intuition.

Also in the heat retention / pressure retention means, for example, in the above 1), it is difficult to blow 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. Or need
In 2) above, the exhaust heat of the air that has entered the boiler is used, so the boiler will eventually cool over time, and the effect of heating and pressurizing it for a large-scale device. Is few.

Further, in the above 3), it is usual that only the exhaust heat of the boiler's blow water is not sufficient for keeping the heat of a boiler of the same capacity, and only in a limited number of cases. Not only is it not available, but it also has the drawback of not being able to start the boiler immediately. That is, since the boiler in the combustion stopped state is filled with the blower water, the boiler water must be blown to the normal water level even if the start-up combustion instruction is given. Therefore, it will take a considerable amount of time to prepare for booting while blowing. Furthermore, in the above 4), a pressure holding burner is additionally required,
In the above 5), two upper and lower connecting pipes and valves are required, and in 6), 7) and 8) above, heat exchange pipes and heat exchangers are required respectively, so let's operate them without much manpower. If this is the case, it will not be possible to use it as a practical problem because it is not a fairly expensive facility.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to stop combustion at an inexpensive cost in the current normal use condition. The state of the boiler is scientifically understood, that is, the temperature of the boiler main body is qualitatively grasped and then first heated, and then the steam pressure is grasped and increased in pressure. An object of the present invention is to provide a method and an apparatus for heating / pressurizing so as to keep the normal boiler equipment as it is and automatically keep it in a heat-retained / pressure-held state without human labor.

[0012]

In order to achieve the above-mentioned object, a method and apparatus for keeping pressure and heat of a boiler in which combustion is stopped according to the present invention include a temperature detector installed near a bottom of a main body of the boiler. A signal and a signal from the steam pressure controller of the boiler are sent to the heating / pressurizing controller, and an on / off signal of heating / pressurizing from the heating / pressurizing controller is sent to the controller, A heating / pressurizing device is started and stopped by a controller so that the temperature and pressure of the boiler are maintained at predetermined values.

[0013]

[Operation] The temperature and pressure of the boiler when combustion is stopped will decrease with time, and when the temperature and pressure or the temperature has decreased to a specified value, the heating / pressurizing device for each boiler or standard equipment The burner is automatically burnt, and when it reaches a predetermined temperature and pressure, it is automatically stopped to automatically and safely maintain the temperature and pressure within a predetermined range.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment in which the present invention is applied to a boiler facility in which a plurality of round boilers are installed. Figure 1
11 and 12 are boiler main bodies in which a plurality of cans are arranged in parallel, and main steam valves 21, 22 ..., Main steam pipes 31, 32, ... , 42 ... Are provided. Reference numeral 5 is a collector pipe side to which the collector pipe inlet / outlet valves 41, 42 ...
Is the main steam outlet pipe. In addition, 71, 72 ... Are steam pressure regulators for each boiler, and 81, 82 ... Are burners for each boiler.

In the boiler facility, the main steam valves 21, 22 ... And the collecting pipe inlet valves 41, 42 ... In normal operation.
Are fully opened, but when the heat demand load decreases and, for example, combustion of the boiler 11 is stopped, the boiler 11 is stopped manually or automatically by the control panel 9 that constitutes the controller, and the boiler 11 is set to standby. Therefore, it is usually necessary to maintain the heat and pressure of the boiler 11.

In this case, for example, the inlet valve of the pipe side 5 may be different depending on whether it is judged that the boiler 11 may be stopped for a while or whether the operation should be restarted immediately. Either 41 is left open or "closed" or closed "block". In any case, when there is a demand for steam, the boiler 11 is immediately kept warm so that it can be put under the normal operation sequence.・ It is necessary to keep pressure and always prepare. At this time, the temperature and pressure of the boiler 11 will decrease with the time of stop due to the heat radiation, and accordingly it is necessary to give instructions to start combustion of heating / pressurization for heat retention / pressure retention. Becomes

Therefore, the boiler 1 in the case where the boiler 11 is in communication with another can and in the case where it is in a block state is used.
When the temperature change in 1 is examined, it becomes as shown in FIG. That is, in FIG. 2, on the right side, the position of the temperature detector attached to the outer surface of the boiler can is shown as a point below the water surface near the water surface (upper), a center (middle) and a point near the bottom (lower). The temperature change at the measurement point is shown on the left side. Then, in FIG. 1, (top 1), (middle 1), (bottom 1), (top 2),
(Middle 2) and (Lower 2) show these positions.
Further, the solid line in FIG. 2 shows the state of the boiler in the "communication", and the broken line shows the state of the "block".

First, in the case of "communication", since the valves 21 and 41 in the normal operating state are left fully open, the boiler 11 that has stopped combustion resumes combustion and enters the operating sequence as it is. It is in. Therefore, when the combustion of the boiler is stopped, its heat radiation starts and the temperature of the boiler water in the boiler begins to decrease, but the pressure is the same as that of the adjacent boiler 1.
Since it communicates with the second boiler 2, it is kept at a predetermined pressure, and the steam latent heat corresponding to the heat release is eventually generated in the stop boiler 1
1, the amount of steam is condensed and accumulated in the boiler, and the water surface 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) 2 hours after the combustion is stopped in the "communication" will be explained. The water surface is at NWL2 which is almost the same as NWL0 during 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 A2 line near the line A of the temperature Ts having a certain difference in the saturation temperature with respect to the pressure at the (upper) and (middle) points, and from the line A at the (lower) point. It's falling apart. Similarly, in the situation after 13 hours (solid line A13), the water surface is higher than the initial position at NWL13, and the temperature at that point is considered to be on the A line corresponding to the above-mentioned temperature Ts, but it is measured. The values (A13) at the points (upper), (middle), and (lower) are significantly lower than those of the A line. Also, in the situation after 24 hours (solid line A24), the water surface is N
The temperature has risen to WL24, and the temperature has further decreased in (upper), (middle), and (lower).

On the other hand, in FIG. 2, the boiler is a "block".
In this state, when the heat demand load decreases, the boiler 1
1 is manually or automatically stopped to stop the operation of the boiler due to a situation that the operation of the stopped boiler is not expected for a while, and the main steam valve 21 of the boiler or the inlet valve 41 near the pipe is closed. Is. Therefore, in this case, since the boiler is cut off from the normal operation system, the pressure of the boiler begins to drop as the temperature decreases along with the heat radiation, and the water surface maintains the initial state. The state of this temperature change is shown by broken lines B2, B13 and B24 in FIG.

As can be seen from FIG. 2, the difference in the temperature detected by the temperature detector at the (lower) point of the boiler body in the "communication" and the "block" is different from the other (upper) and (middle). The difference is the smallest in comparison, and the difference in (bottom) is 10 ° C or less even if it is large, and becomes several degrees or less with time. Regarding the degree of decrease in temperature with time, there is not much difference between (upper) and (middle), and (lower) significantly decreases.

The temperature as a guide for keeping the boiler warm while combustion is stopped should be based on the difference from the temperature of the boiler main body during normal operation. To detect the temperature difference, The point where the difference is the largest is good, and moreover, as mentioned above, at the point of (bottom), "communication" at the same time
The temperature difference between "block" and "block" is small, and there is no special reason for distinguishing "communication" from "block" in automatic heating and pressurizing operation.

From the above, in the automatic heating and pressurizing operation for maintaining the heat and pressure of the boiler while combustion is stopped, the temperature of the boiler can should be detected as a standard for the temperature at which the automatic operation is performed. The point (bottom) may be measured as the point.
Therefore, as shown in Fig. 1, the temperature detection point of the boiler is set as a point (bottom 1), (bottom 2) ... Close to the bottom of each boiler, and a temperature detector is installed at that point and the signal is heated / heated. Pressure regulator 10
1,102 ..., heating from the heating / pressurizing controller
The pressurization start / stop signal is sent to the control panel 9 constituting the controller.

At this time, for example, the temperature at the point (bottom 1) after the combustion is stopped is 2 from the temperature during normal operation (on the Ts or A line).
When the temperature drops from 0 ° C to 30 ° C, first, heating / pressurization controller 1
01 and the control panel 9 are used to automatically start and burn the stopped boiler to keep the temperature constant, and the temperature reaches a predetermined level and the steam pressure reaches a predetermined pressure. The heating / pressurizing controller 10 is not necessary.
1 confirms that the control panel 9 is used to stop the combustion.
If a stop signal is sent to the automatic heating / pressurizing device or the burner 81 via the, the automatic heating / pressurizing operation for maintaining the temperature / pressure of the boiler during the stop is approximately 12 to 24. It will be done automatically once a time.

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

[0026]

EFFECT OF THE INVENTION According to the method and apparatus for keeping pressure and heat of a boiler during combustion stop according to the present invention, a temperature detector installed near the bottom of the main body of the boiler where the temperature changes remarkably during combustion stop The temperature is monitored quantitatively, and it is heated by a predetermined temperature difference from its normal use, and when the boiler is blocked, heating is continued until the steam pressure rises to a predetermined level, Since the pressure and temperature are maintained, the pressure and temperature of the boiler can be reliably and automatically maintained at low cost without changing the equipment of the conventional boiler, and restarting can be facilitated.

There is little fear of unexpected problems such as the boiler not catching up due to a rapid increase in heat demand load, and quantitative and rational temperature monitoring of the boiler keeps the boiler safe and warm so that it can be operated safely. The pressure is obtained.

[Brief description of drawings]

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

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

[Explanation of symbols]

 11, 12 ... Boiler main 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 / pressurizing regulator Lower 1, Lower 2 ... Temperature sensor installation position A2, A13, A24 Temperature condition during communication B2, B13, B24 Temperature condition during block

Front page continuation (72) Inventor Ryoji Takeyama 1-4-2 Marunouchi, Chiyoda-ku, Tokyo Marunouchi Heat Supply Co., Ltd. (72) Inventor Hiroshi Kobayashi 1-9-36 Oyodokita, Kita-ku, Osaka (72) Inventor Eisuke Yamaguchi 1-9-36 Oyodokita, Kita-ku, Osaka Hirakawagai Dam Co., Ltd.

Claims (3)

[Claims] 1. A heat insulation system for a blocked boiler during combustion stoppage in a boiler facility equipped with a single can or a plurality of cans.
In the pressure maintaining 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 to adjust the heating / pressurizing. A heating / pressurizing start / stop signal from the heater is sent to the controller, and the controller starts / stops the heating / pressurizing device to maintain the temperature and pressure of the boiler at predetermined values. Characterizing method for keeping heat and pressure of boiler while combustion is stopped. 2. A method for keeping the temperature and pressure of a boiler which is in a combustion stop and which communicates with other cans in a boiler facility having a plurality of cans, wherein a signal from a temperature detector installed near the bottom of the main body of the boiler is used. It is sent to the heating / pressurizing controller, the heating start / stop signal from the heating / pressurizing adjuster is sent to the controller, and the controller starts / stops the heating device. A method of keeping heat and pressure of a boiler during combustion stop, characterized by keeping temperature and pressure at predetermined values. 3. A heat retention / pressure retention device for a boiler in which combustion is stopped in a boiler facility having a single can or a plurality of cans, wherein a temperature detector is installed near the bottom of the main body of the boiler, and the temperature detector and the Connect the output part of the heating / pressurizing controller connected to the steam pressure controller of the boiler to the controller,
A heat retention / pressure retention device for a boiler during combustion stop, wherein an output part of the controller is connected to a burner and a main steam valve of the boiler.