JP4148492B2 - Boiler with heat storage - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a boiler with a heat-storage material.
[0002]
[Prior art]
Combustion control in a small boiler is controlled according to the value of the steam pressure (steam temperature). When the steam pressure value falls below the lower limit value, combustion is performed, and when it exceeds the upper limit value, combustion is stopped. Yes. When the boiler is burned, high-temperature combustion gas heats the water pipe, and the can water in the water pipe evaporates to generate steam. By performing combustion and supplying steam, the steam pressure rises, and when the steam pressure value rises to the upper limit value, the combustion is stopped. While the combustion is stopped, the steam supply is not performed, so the steam pressure decreases. When the steam pressure value drops to the lower limit value, the combustion is resumed, and then combustion is started and stopped according to the steam pressure value. Repeat that. When starting the combustion of the boiler, it is necessary to remove the combustible components from the furnace before ignition. Therefore, before starting the combustion, pre-purge to ventilate the furnace by operating the blower and supplying pre-purge air to the furnace. After doing so, start burning.
[0003]
When the boiler is combusting, the amount of combustion can be increased or decreased simply by increasing or decreasing the fuel supply amount and the combustion air supply amount, so that the combustion amount can be increased or decreased in accordance with the required steam amount. However, when the combustion of the boiler is stopped, even if the steam pressure value decreases and the steam supply needs to be restarted, steam cannot be generated immediately, and the followability becomes worse. Pre-purge is required at the start of boiler combustion, and steam cannot be supplied while pre-purge is being performed, so the steam pressure decreases during that time. Moreover, since the pre-purge air is room temperature air, the pre-purge is performed to cool the water pipe and the can water in the water pipe. When the can water temperature is low, steam is still generated until the can water temperature rises after the start of combustion. It cannot be supplied.
[0004]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to improve the followability to the steam demand even in a boiler that stops combustion.
[0005]
[Means for Solving the Problems]
A boiler that heats a water pipe with combustion gas generated by operating a burner and a blower and heats can water in the water pipe to generate steam, and the operation of the boiler is performed according to the pressure value of the steam. If the steam pressure is lowered and combustion is performed, combustion is performed in a boiler that performs pre-purge to ventilate the furnace by operating the blower and sending pre-purge air into the furnace before starting combustion. A combustion chamber for generating combustion gas and a combustion gas passage for heating the water pipe through the combustion gas sent from the combustion chamber are provided, and the combustion gas is moved from the combustion chamber to the combustion gas passage. combustion gas is installed regenerator to the portion of the upstream side to the combustion gas stream to a portion of the flow of, at the time of burner combustion Ru contacting a combustion gas generated by operating the burner and blower in regenerator And, the stored heat in the heat storage body to convey the heat of the combustion gas to the regenerator, during the pre-purge contacting the pre-purge air to the regenerator, the play purge air heated by the heat that has been accumulated in the regenerator, heated pre-purge air To heat the water tube .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an outline of a boiler embodying the present invention, and FIG. 2 is a cross-sectional view taken along line AA of FIG. An annular upper header 1 is provided at the upper portion of the can body, and an annular lower header 2 is provided at the lower portion, and the upper and lower headers are connected by a large number of inner water tubes 3 and outer water tubes 4 arranged in a ring shape. . Portions other than the lower part of the inner water pipe 3 and the upper part of the outer water pipe 4 are closed between the adjacent water pipes by the closing fins 8 parallel to the pipe axis direction, and between the inner water pipe 3 and the outer water pipe 4. A combustion gas passage 7 is provided. A boiler central portion surrounded by the inner water pipe 3 is a combustion chamber 9, and a burner 10 is provided above the combustion chamber 9.
[0007]
The combustion gas passage 7 and the combustion chamber 9 are connected to each other at a portion where the closing fin 8 is not provided at the lower portion of the inner water pipe, and the combustion gas generated in the combustion chamber 9 enters the combustion gas passage 7 from the lower portion of the inner water pipe. 7 flows upward. A heat absorption fin 11 is provided on the side of the outer water pipe 4 facing the combustion gas passage 7, and the combustion gas flows while heating the heat absorption fin 11. The combustion exhaust gas that has reached the upper part of the combustion gas passage 7 is taken out and exhausted through a part of the upper part of the outer water pipe where the closing fins 8 are not provided.
[0008]
A heat storage body 12 having heat resistance and capable of storing heat is provided at a lower portion of the combustion gas passage 7 and upstream of the combustion gas flow. The material of the heat storage body 12 is preferably a material that emits less heat when there is no air flow and easily transfers heat inside the heat storage body, and ceramics such as alumina are suitable. The heat storage body 12 has a large number of holes so as not to resist the flow of the combustion gas, so that the heat of the combustion gas can be easily transmitted to the heat storage body 12, and conversely, the heat of the heat storage body 12 can be easily transmitted to the pre-purge air. Structure.
[0009]
A blower 13 that supplies air to the burner 10 and a fuel supply control device 14 that controls the fuel supply to the burner 10 are provided. The blower 13 and the fuel supply control device 14 include an operation control device 6 that controls the operation of the boiler, and Connecting. The operation control device 6 is connected to a pressure detection device 5 that detects the steam pressure value of the boiler, and controls the operation of the boiler based on the steam pressure value detected by the pressure detection device 5.
[0010]
When the steam pressure value detected by the pressure detection device 5 falls below a predetermined lower limit value, the operation control device 6 starts combustion of the boiler. The operation control device 6 first operates the blower 13 to supply pre-purge air into the combustion chamber 9 and performs pre-purge to ventilate the combustion chamber 9. The operation control device 6 burns the burner 10 by operating an ignition device (not shown) and opening the fuel supply control device 14 after completing the pre-purge for a predetermined time.
[0011]
When the burner 10 is burned, high-temperature combustion gas is generated in the combustion chamber 9. The combustion gas enters the combustion gas passage 7 from the lower part of the inner water pipe 3 and flows upward in the combustion gas passage 7. Since the heat storage body 12 is provided in the lower part of the combustion gas passage on the upstream side of the combustion gas flow, the combustion gas that has reached the heat storage body 12 exchanges heat with the heat storage body 12 and heats the heat storage body 12. The combustion gas that has passed through the heat storage body 12 flows while heating the surfaces of the inner water tube 3 and the outer water tube 4 and the heat absorbing fins 11. When the water pipe is heated, the temperature of the can water in the water pipe rises, and the can water boils and generates steam.
[0012]
When the steam pressure rises due to the generation of steam and the steam pressure value detected by the pressure detection device 5 rises to a predetermined upper limit value, the operation control device 6 closes the fuel supply control device 14 and turns the blower 13 on. Stop and stop boiler operation. When the combustion is stopped, the supply of steam is lost, so the steam pressure value decreases. When the steam pressure value decreases to the lower limit value, the operation control device 6 resumes the combustion of the boiler.
[0013]
When the combustion is started, pre-purge is required, and when the blower 13 is operated and pre-purge is performed in a state where the heat storage body 12 stores heat, heat exchange occurs between the pre-purge air and the heat storage body 12. When the pre-purge air and the heat storage body 12 come into contact, the heat stored in the heat storage body 12 is transferred to the pre-purge air, and the heat storage body 12 heats the pre-purge air. The pre-purge air heated by the heat accumulator 12 heats the surfaces of the inner water pipe 3 and the outer water pipe 4 and the heat absorbing fins 11 when passing through the combustion gas passage 7. Since the outer water pipe 4 is provided with the heat-absorbing fins 11, a particularly large amount of heat is transmitted, and steam is generated when the can water in the outer water pipe 4 is heated and boiled. Since the heat absorption fins 11 are not provided on the surface of the inner water pipe 3 on the combustion gas passage 7 side, the inner water pipe 3 is not heated as much as the outer water pipe 4, but is heated by high-temperature pre-purge air. It is not cooled at least by pre-purge.
[0014]
By heating the water pipe with the pre-purge air, steam can be generated during the pre-purge, and the water pipe and the can water in the water pipe are not cooled by the pre-purge air. It can prevent that a pressure value falls.
[0015]
If the flame directly touches the heat storage body 12, combustion may be incomplete. Therefore, the heat storage body 12 is provided in the combustion gas passage 7 and the heat storage body 12 is heated by the combustion gas after combustion. Good.
[0016]
【The invention's effect】
By practicing the present invention, steam can be supplied before combustion is started, so that the boiler can withstand steam load requirements.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an outline of a boiler embodying the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG.
DESCRIPTION OF SYMBOLS 1 Upper header 2 Lower header 3 Inner water tube 4 Outer water tube 5 Pressure detection device 6 Operation control device 7 Combustion gas passage 8 Closing fin 9 Combustion chamber 10 Burner 11 Heat absorption fin 12 Heat storage body 13 Blower 14 Fuel supply control device

Claims (2)

A boiler that heats a water pipe with combustion gas generated by operating a burner and a blower, and operates the blower before the start of combustion to send pre-purge air into the furnace and perform pre-purge to ventilate the furnace. In the boiler, a combustion chamber for generating combustion gas by combustion and a combustion gas passage for heating the water pipe through the combustion gas sent from the combustion chamber are provided, and the combustion gas is moved from the combustion chamber to the combustion gas passage. In addition, a heat accumulator is installed in the portion where the combustion gas flows in the combustion gas passage and is upstream of the combustion gas flow, and the combustion gas is brought into contact with the heat accumulator during burner combustion , thereby reducing the heat of the combustion gas. It is transmitted to the heat storage body to store heat in the heat storage body. During pre-purge, the pre-purge air is brought into contact with the heat storage body, and the pre-purge air is heated by the heat stored in the heat storage body. Regenerator with boiler being characterized in that to allow Rukoto. The boiler with a heat storage body according to claim 1, wherein the heat storage body has a large number of holes so as not to be resistant to the flow of combustion gas .

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