JP6922585B2 - Boiler device - Google Patents

Description

The present invention relates to a boiler device that burns fuel to generate steam.

Conventionally, as a boiler device, there is known a boiler device that generates steam by heating water supplied from a water supply pipe with combustion gas generated by burning fuel in the boiler body (can body). .. In such a boiler device, in order to improve the heat exchange efficiency, an economizer is provided to preheat the water supplied from the water supply pipe by using the heat of the exhaust gas.

With the passage of time, soot and the like contained in the exhaust gas of the economizer adhere to the water supply pipe in the economizer and accumulate, so that the heat exchange efficiency decreases. For this reason, there is known a technique of periodically injecting steam, water, or the like toward a water supply pipe in an economizer to perform so-called soot blow to remove soot from the water supply pipe (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 11-82985

However, with the improvement of boiler efficiency and the expansion of turndown ratio (TDR) in recent years, the temperature of the exhaust gas at the time of low combustion in the boiler device is lower than before. Therefore, if combustion is started with water adhering to the surface of the water supply pipe in the economizer after the soot blow is completed, the low-temperature exhaust gas will pass through the economizer. As a result, the sulfur content in the exhaust gas dissolves in the water adhering to the surface of the water supply pipe, causing the generation of sulfurous acid and thus sulfuric acid. Then, the water supply pipe may be corroded.

The present invention has been conceived in view of such circumstances, and an object of the present invention is to provide a boiler device capable of preventing corrosion of a water supply pipe in an economizer.

In order to achieve the above object, the boiler device according to a certain aspect of the present invention includes a boiler main body that burns fuel to generate steam, a blower that blows air into the boiler main body, and an economizer provided with a water supply pipe. An injection unit provided in the economizer that injects water or steam toward the water supply pipe, and by receiving a first operation or signal, the operation mode of the device is set to inject water or steam from the injection unit. The control means is provided with a control means for shifting to the cleaning mode for the purpose, and the control means does not allow the transition to the cleaning mode when the operation mode of the device is the burning mode, and waits instead of the combustion mode. When the mode is set, the transition to the cleaning mode is allowed, and after the cleaning mode is finished, the operation mode of the device is shifted to the drying mode in which the blower is driven to dry the surface of the water supply pipe.

According to the above configuration, after the cleaning mode is completed, the surface of the water supply pipe can be dried by shifting to the drying mode by the control means. Therefore, after the cleaning mode is completed, it is possible to prevent combustion from starting with water adhering to the surface of the water supply pipe. As a result, it is possible to prevent the water supply pipe in the economizer from being corroded by the water used for cleaning. Further, since the blower that blows air into the boiler body is also used in the drying mode, it is possible to suppress an increase in the number of parts of the boiler device and an increase in manufacturing cost.

Preferably, the control means terminates the cleaning mode and shifts the operating mode of the device to the drying mode by receiving a second operation or signal in the cleaning mode.

According to the above configuration, since no new operation is required when shifting to the drying mode, it is possible to reliably shift to the drying mode after the cleaning mode is completed.

It is a figure which shows typically the structure of the boiler device. It is a time chart which shows the operation of a boiler device.

<About the outline configuration>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a schematic configuration of the boiler device 1 according to the present embodiment will be described with reference to FIG. The boiler device 1 includes a boiler main body 2 that burns fuel to generate steam, a blower 3 that sends air into the boiler main body 2, a flue 4 that derives exhaust gas from the boiler main body 2, and a flue 4. It is equipped with an economizer 5 connected to one end. The economizer 5 is provided with a water supply pipe 6 for supplying water to the boiler main body 2 and an injection unit 7 for cleaning the water supply pipe 6 inside.

Fuel is supplied to the boiler main body 2 via the fuel supply path 21. The fuel supply path 21 is provided with an oil amount adjusting valve 21a for adjusting the flow rate of the fuel to be supplied. The steam generated in the boiler main body 2 is sent to the destination via the steam path 22. The steam path 22 is provided with a main steam valve 22a for supplying or stopping steaming. The blower 3 operates in a "combustion mode" in which fuel is burned in the boiler main body 2, and sends air necessary for ventilation (purge) and combustion in the boiler main body 2. The economizer 5 preheats the water in the water supply pipe 6 by using the heat of the exhaust gas from the boiler main body 2 sent through the flue 4.

In the boiler device 1 provided with the economizer 5, soot and the like contained in the exhaust gas adhere to and accumulate on the heat transfer surface of the water supply pipe 6 with the passage of time, and the heat exchange performance deteriorates. Therefore, the injection unit 7 provided in the economizer 5 injects water or steam toward the water supply pipe 6 by opening the valve 7a in the "cleaning mode (soothing blow mode)". As a result, the soot of the water supply pipe 6 is washed, so the soot and the like adhering to the surface of the water supply pipe 6 are removed. A washing water drainage path 8 for discharging the drainage after washing is connected to the downstream side of the economizer 5. On the wash water drainage path 8, a valve 8a for opening and closing the wash water drainage path 8 and an inspection unit 8b having a glass window for visually observing the drainage are provided.

In this way, the water supply pipe 6 can be cleaned by the operation of the injection unit 7, and after the cleaning mode is completed, the operation mode of the boiler device 1 is set to the combustion mode with water adhering to the surface of the water supply pipe 6. If it is transferred to, the sulfur content in the exhaust gas may dissolve and sulfurous acid or sulfuric acid may be generated. Therefore, the boiler device 1 in the present embodiment shifts to a "drying mode" in which the surface of the water supply pipe 6 is dried as an operation mode after the cleaning mode is completed.

The operation mode of the boiler device 1 and the on-board equipment (including the blower 3, the oil amount adjusting valve 21a, etc.) are controlled by the control device 10. The control device 10 is connected to an operation unit 11 for receiving an operation from an operator and a display unit 12 for displaying information and the like regarding the current operation mode. The operation unit 11 is, for example, a combustion start operation for starting the combustion mode, a combustion end operation for ending the combustion mode, a cleaning start operation for starting the cleaning mode, and an operation for ending the cleaning mode. Accepts multiple operations including cleaning end operation.

The control device 10 changes the operation mode of the boiler device 1 to the cleaning mode in response to receiving the cleaning start operation (first operation) in the state where the combustion mode is completed (hereinafter, also referred to as the standby state). Migrate. Further, the control device 10 terminates the cleaning mode in response to receiving the cleaning end operation (second operation), and forcibly shifts the operation mode of the boiler device 1 to the drying mode. As a result, after cleaning the water supply pipe 6, the combustion mode is not entered even if the combustion start operation is performed, unless the surface of the water supply pipe 6 is dried.

<About operation>
The operation of the boiler device 1 according to the present embodiment will be described with reference to FIG. FIG. 2 shows the transition pattern of the operation mode, the ON / OFF state of the blower 3 in each operation mode, the possibility of the combustion start operation, and the display contents on the display unit 12.

The control device 10 performs a cleaning promotion display prompting cleaning on the display unit 12 when a predetermined promotion display condition is satisfied. The promotion display condition is, for example, a condition that is satisfied when the cumulative combustion time since the last cleaning reaches a predetermined time, and a condition that is satisfied when the temperature detected by the exhaust gas thermostat is equal to or higher than the predetermined temperature. Including the conditions to be used. In the standby state, the combustion start operation and the cleaning start operation can be performed. When the control device 10 receives the cleaning start operation in the standby state (t1), the operation mode of the boiler device 1 shifts from the standby state to the cleaning mode. When the mode shifts to the cleaning mode, the display unit 12 indicates that the cleaning mode is in progress.

When shifting to the cleaning mode, the combustion start operation is disallowed. By manually opening the valve 7a in the cleaning mode, water or steam is injected from the injection unit 7 to clean the water supply pipe 6. Further, in the cleaning mode, by manually opening the valve 8a, the operator can visually check the degree of dirtiness of the drainage through the glass window of the inspection unit 8b. By cleaning the drainage, the operator can determine that the water supply pipe 6 has been cleaned cleanly. When stopping the injection from the injection unit 7, the valve 7a is manually closed. Further, after the drainage is completed, the valve 8a is manually closed. After that, when the operation unit 11 receives the cleaning end operation (t2), the operation mode of the boiler device 1 shifts from the cleaning mode to the drying mode. When the mode shifts to the drying mode, the display unit 12 indicates that the drying mode is in progress. Even in the dry mode, the combustion start operation remains disallowed. As a result, from the start of the cleaning mode to the end of the drying mode, the control device 10 is controlled so as not to shift to the combustion mode even if the combustion start operation is performed.

In the drying mode, the control device 10 automatically starts driving the blower 3 when the cleaning mode ends. As a result, the surface of the water supply pipe 6 in the economizer 5 can be dried by the air sent to the economizer 5 through the boiler main body 2 and the flue 4. When the control device 10 detects that a predetermined time has elapsed from the start of drying (t3) based on, for example, a time signal from the timer, the control device 10 ends the drying mode (stops the blower 3) and controls the standby state. The predetermined time is a time during which the surface of the water supply pipe 6 can be sufficiently dried, and has a meaning different from the execution time of the pre-purge for ventilation. The predetermined time may be, for example, a predetermined time (for example, 3 minutes) or a time arbitrarily set by the operator (for example, a time set from between 3 minutes and 10 minutes). good.

In the standby state after the end of the drying mode, the combustion start operation is permitted. As a result, the transition to the combustion mode becomes possible at any time. When the combustion start operation is accepted in the standby state (t4), the operation mode of the boiler device 1 shifts from the standby state to the combustion mode. At this time, the display unit 12 indicates that the combustion mode is in progress. In the combustion mode, combustion is started after pre-purge is performed by driving the blower 3.

As described above, in the present embodiment, when the operation unit 11 receives the cleaning end operation and the cleaning mode ends, the mode is forcibly shifted to the drying mode. Therefore, the surface of the water supply pipe 6 is shifted to the combustion mode without being dried. It is possible to surely prevent or suppress the corrosion of the water supply pipe 6 without being prevented.

Further, in the drying mode of the present embodiment, the water supply pipe 6 is dried by using the blower 3 that sends air for combustion in the boiler main body 2, so that the number of parts of the boiler device 1 is increased and the manufacturing cost is increased. Can be suppressed from rising.

The present invention is not limited to the above-described embodiment, and various modifications and applications are possible. Hereinafter, variations of the above-described embodiment applicable to the present invention will be described.

In the above-described embodiment, an example of shifting to the cleaning mode by the cleaning start operation has been described. However, the transition to the cleaning mode is not limited to this, and may be automatically performed in response to receiving a signal from a sensor or a timer. For example, the transition to the cleaning mode may be automatically performed when the combustion end operation is accepted and the combustion mode ends in a state where the above-mentioned promotion display condition is satisfied.

In the above-described embodiment, an example in which the cleaning mode is shifted to the drying mode by the cleaning end operation has been described. However, the transition from the washing mode to the drying mode is not limited to this, and may be automatically performed in response to receiving a signal from a sensor or a timer. For example, the transition from the washing mode to the drying mode is automatically performed when a predetermined time (for example, 5 minutes) has elapsed from the start of washing based on the time signal from the timer. You may. Further, although the example in which the drying mode ends after a lapse of a predetermined time has been described, the drying mode is not limited to this, and may be terminated according to a predetermined operation (for example, a drying end operation) on the operation unit 11.

In the above-described embodiment, the injection and the stop from the injection unit 7 have been described as examples in which the injection and the stop are performed manually, but the present invention is not limited to this, and the injection and the stop may be performed automatically. For example, a solenoid valve is adopted as the valve 7a, and the injection start condition (for example, cleaning start operation, cleaning mode start, etc.) and the injection stop condition (for example, cleaning end operation, cleaning mode end, etc.) are satisfied, which are predetermined. The solenoid valve may be driven by the control device 10 according to the passage of time (elapsed of 5 minutes, etc.). When the control device 10 adopts the injection stop condition by the lapse of a predetermined time, even when the cleaning end operation or the like is accepted when the predetermined time has not elapsed and the injection unit 7 has not stopped. The cleaning mode may not be terminated. As a result, it is possible to prevent the mode from shifting to the drying mode in the state of being injected from the injection unit 7. Further, the valve 8a may also employ a solenoid valve and be driven by the control device 10 in conjunction with the solenoid valve for injecting and stopping from the injection unit 7.

In the above embodiment, when the cleaning mode is shifted immediately after the combustion mode ends, the drying efficiency in the subsequent drying mode can be improved depending on the operating time of the cleaning mode. This is because the boiler body 2 itself is hot even when the mode is changed to the drying mode, and the air warmed by the boiler body 2 is sent to the economizer 5. Therefore, in the case where the injection stop condition after the lapse of a predetermined time is adopted, if it is immediately after the end of the combustion mode (for example, the temperature is equal to or higher than the predetermined temperature by the thermostat that detects the temperature inside the boiler body 2), the combustion mode ends. A shorter time may be set as a predetermined time for shifting to the drying mode than when not immediately after. As a result, the time from the start of the cleaning mode to the end of the drying mode can be shortened by shifting to the cleaning mode immediately after the end of the combustion mode.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Boiler device 2 Boiler body 3 Blower 4 Smoke channel 5 Economizer 6 Water supply pipe 7 Injection section 7a valve 8 Washing water drainage path 8a Valve 8b Inspection section 10 Control device 11 Operation section 12 Display section 21 Fuel supply path 21a Oil level adjustment valve 22 Steam path 22a Main steam valve

Claims (2)

The boiler body that burns fuel to generate steam,
A blower that blows air into the boiler body and
An economizer with a water supply pipe and
An injection unit provided in the economizer and injecting water or steam toward the water supply pipe.
A control means for shifting the operation mode of the device to a cleaning mode for injecting water or steam from the injection unit by receiving the first operation or signal is provided.
The control means
When the operation mode of the device is the combustion mode during combustion, the transition to the cleaning mode is not allowed, and when the operation mode is the standby mode instead of the combustion mode, the transition to the cleaning mode is allowed.
A boiler device that shifts the operation mode of the device to a drying mode in which the blower is driven to dry the surface of the water supply pipe after the cleaning mode is completed. The boiler device according to claim 1, wherein the control means terminates the cleaning mode and shifts the operation mode of the device to the drying mode by receiving a second operation or signal in the cleaning mode. ..

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