CN215336289U - Low-temperature economizer and circulating fluidized bed boiler - Google Patents
Low-temperature economizer and circulating fluidized bed boiler Download PDFInfo
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- CN215336289U CN215336289U CN202121492331.3U CN202121492331U CN215336289U CN 215336289 U CN215336289 U CN 215336289U CN 202121492331 U CN202121492331 U CN 202121492331U CN 215336289 U CN215336289 U CN 215336289U
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Abstract
The application discloses a low-temperature economizer and a circulating fluidized bed boiler, which comprise a coal-saving box, wherein a coal-saving flue communicated with a flue at the tail part of the boiler is arranged in the coal-saving box, a temperature control tube bundle communicated with a cold water inlet header and a hot water outlet header is arranged in the flue, and the hot water outlet header is communicated with a No. 5 low-pressure heater on the boiler; the slag cooler is communicated with a slag cooling guide pipeline of the water flow inlet header and communicated with a high-temperature water guide pipeline of the hot water outlet header and the water flow inlet header. The coal economizer realizes the regulation and control of the exhaust gas temperature of the boiler, and solves the problems of blockage of the full-combustion coal slime boiler during the operation at lower load and high exhaust gas temperature during high load. The low-temperature economizer and the circulating fluidized bed boiler meet the requirement of a large coal slime boiler on the exhaust gas temperature, and prevent the problems that low-temperature smoke corrodes a pipeline, blocks ash and high-temperature smoke damages the boiler and influences the boiler efficiency.
Description
Technical Field
The application relates to the technical field of coal-fired power generation boiler equipment, in particular to a low-temperature economizer and a circulating fluidized bed boiler.
Background
Coal slurry is broadly a semi-solid formed by coal fines containing water and is a product in the coal production process. The coal slime is listed as industrial solid waste, and the existing solution of the large-batch coal slime is to be sent to a coal-fired power plant as fuel of a circulating fluidized bed boiler. When coal slime is combusted in the hearth of the circulating fluidized bed boiler, the circulating fluidized bed boiler unit needs to participate in deep peak shaving. For the current circulating fluidized bed boiler unit, the full combustion coal slime can be safely operated under the rated load of 45% -80%, but for the circulating fluidized bed boiler unit to be changed into the full combustion coal slime, the operation under the load of 30% -100% brings the following two problems to the boiler:
1) when the boiler is fully loaded, because the moisture content of the coal slime is high, the exhaust gas temperature of the boiler can reach more than 180 ℃, the heat loss is increased, the boiler efficiency is reduced, the economic benefit of a power plant is reduced, and simultaneously the afterburning at the tail part of the boiler can be caused, so that the cloth bag of a dust remover is burnt, and the safe operation of the boiler is endangered;
2) after the unit participates in deep peak shaving, when the load is 30%, the exhaust gas temperature of the boiler is lower than the normal exhaust gas temperature (135 ℃) of the boiler, and for the exhaust gas with the low temperature, the moisture in the exhaust gas is easy to be condensed into water on the heat exchange pipe of the air preheater at the tail part of the circulating fluidized bed boiler unit, so that low-temperature corrosion is generated on the heat exchange pipe, and meanwhile, due to the generation of the moisture, the ash content in the exhaust gas is bonded on the outer wall of the heat exchange pipe, so that the pipeline is blocked, and the boiler is stopped forcibly or stopped seriously.
Content of application
The application provides a low temperature economizer and circulating fluidized bed boiler to solve present circulating fluidized bed boiler unit and in the full combustion coal slime operation process under 30% -100% load, the exhaust gas temperature of boiler is too high or low excessively, thereby influences the problem of boiler normal operating.
The application provides a low-temperature economizer which comprises a coal-saving box, wherein a coal-saving flue communicated with a tail flue of a boiler is arranged in the coal-saving box, a temperature control tube bundle is arranged in the coal-saving flue, one end of the temperature control tube bundle is communicated with a cold water inlet header, the other end of the temperature control tube bundle is communicated with a hot water outlet header, and the hot water outlet header is communicated with an inlet end of a No. 5 low-pressure heater on the boiler;
the low-temperature economizer also comprises a cold slag guide pipeline and a high-temperature water guide pipeline, wherein the water inlet end of the cold slag guide pipeline is communicated with the outlet pipe of the slag cooler of the boiler, and the water outlet end of the cold slag guide pipeline is communicated with the water flow inlet header;
the water inlet end of the high-temperature water guide pipeline is communicated with the hot water outlet header, and the water outlet end of the high-temperature water guide pipeline is communicated with the water flow inlet header.
Optionally, a cold slag valve is arranged on the cold slag guide pipeline.
Optionally, a high-temperature water valve is arranged on the high-temperature water guide pipeline.
Optionally, the low-temperature economizer further comprises a support frame for supporting the economizer box.
The present application further provides a circulating fluidized bed boiler, comprising: the system comprises a drum, a hearth water-cooled wall, a superheater, a reheater, a separator, an ash return valve, an economizer, an air preheater, a coal slime feeding device, a valve, a DCS control system and the low-temperature economizer.
The low-temperature economizer and the circulating fluidized bed boiler realize the regulation and control of the exhaust gas temperature of the boiler, the exhaust gas temperature can be always kept between 130 ℃ and 135 ℃ no matter how the load of the boiler changes, the problem of blockage caused by low-temperature corrosion generated when the full-combustion coal slime boiler operates at a lower load and condensation of the low-temperature corrosion generated when the full-combustion coal slime boiler operates into water is solved, and the problem of high exhaust gas temperature generated when the full-combustion coal slime boiler operates at a high load is solved. The low-temperature economizer and the circulating fluidized bed boiler meet the requirement of a large coal slime boiler on the exhaust gas temperature, and prevent the problems that low-temperature smoke corrodes a pipeline, blocks ash and high-temperature smoke damages the boiler and influences the boiler efficiency.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a view illustrating a usage scenario of the low-temperature economizer of the present application;
FIG. 2 is a sectional elevation view of the low temperature economizer of the present application;
FIG. 3 is a cross-sectional side view of the low temperature economizer of the present application;
FIG. 4 is a sectional top view of the low temperature economizer of the present application;
FIG. 5 is a schematic structural view of a circulating fluidized bed boiler according to the present application;
the reference numerals in fig. 1-5 refer to: 10-a coal-saving box, 20-a coal-saving flue, 30-a temperature control tube bundle, 40-a cold water inlet header, 50-a hot water outlet header, 60-a cold slag guide pipeline, 61-a cold slag valve, 70-a high-temperature water guide pipeline, 71-a high-temperature water valve, 100-a low-temperature coal economizer, an inlet end of an A-5# low-pressure heater and an outlet pipe of a B-a cold slag device.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
For the coal economizer of a common circulating fluidized bed boiler, water in a pipe enters a boiler barrel after being heated by the coal economizer and participates in a water circulation system of the boiler, and the water quantity is changed along with the change of the load of the boiler, so the temperature of exhaust gas is changed, the designed normal value of the temperature of the exhaust gas is 140 ℃, and the normal value corresponds to the rated load of the boiler. After the boiler burns coal slurry, when the boiler operates at rated load or high load, the exhaust gas temperature is up to more than 180 ℃, which is far higher than the normal exhaust gas temperature by 140 ℃, and the exhaust gas with overhigh temperature can easily cause the reburning of the tail fly ash (the carbon content in the fly ash is higher), thus seriously threatening the safe operation of the tail bag-type dust remover. The normal use temperature of the bag-type dust collector is about 150 ℃, the bag-type dust collector is not allowed to run for a long time at the smoke temperature of 180 ℃, otherwise, the bag-type dust collector is burnt. In addition, this also limits the inability of the boiler to operate at full capacity, thereby reducing boiler efficiency. When the low-load operation is carried out, the exhaust gas temperature is lower than 135 ℃, when the exhaust gas temperature is lower than 130 ℃, moisture in the exhaust gas can be condensed into water on the heat exchange pipe of the tail air preheater to generate low-temperature corrosion, and meanwhile, ash in the exhaust gas can be bonded in the pipe due to the generation of the moisture to generate pipe blockage, and forced furnace shutdown can be caused in severe cases.
In order to solve the problems, the application provides a low-temperature economizer capable of adjusting the exhaust gas temperature of a boiler. Fig. 1 is a view of a use scene of the low-temperature economizer of the present application, fig. 2 is a cross-sectional front view of the low-temperature economizer of the present application, fig. 3 is a cross-sectional side view of the low-temperature economizer of the present application, and fig. 4 is a cross-sectional top view of the low-temperature economizer of the present application, as shown in fig. 1-4, the low-temperature economizer includes an economizer box 10, an economizer flue 20 communicated with a boiler tail flue is arranged in the economizer box 10, and a temperature control tube bundle 30 is arranged in the economizer flue 20. One end of the temperature control tube bundle 30 is communicated with a cold water inlet header 40, the other end is communicated with a hot water outlet header 50, and the hot water outlet header 50 is communicated with an inlet end A of a No. 5 low-pressure heater on the boiler. In the present application, the temperature control tube bundle 30 is a group of serpentine steel tubes bent to a desired size and placed in the economizer flue 20.
The low-temperature economizer further comprises a cold slag guide pipeline 60 and a high-temperature water guide pipeline 70, wherein the water inlet end of the cold slag guide pipeline 60 is communicated with a slag cooler outlet pipe B of the boiler, and the water outlet end of the cold slag guide pipeline 60 is communicated with a water flow inlet header. During actual use, the cold water flowing out of the slag cooler outlet pipe B flows into the temperature control tube bundle 30 through the communication with the slag cooler outlet pipe B, and the cold water flow is used for cooling the flue gas, so that the flue gas in the coal-saving flue 20 is cooled. In this application, for the inflow accuse temperature tube bank 30 and the inflow of better control cold water, be equipped with cold sediment valve 61 on the cold sediment guide pipeline 60. Different from the traditional existing economizer, the amount of water entering is changed according to the load change of the boiler, and in the application, the cold slag valve 61 is adjusted according to the change of the exhaust gas temperature, so that the inflow and inflow of cold water entering the temperature control tube bundle 30 are controlled.
The water inlet end of the high-temperature water guide pipeline 70 is communicated with the hot water outlet header 50, and the water outlet end of the high-temperature water guide pipeline 70 is communicated with the water inlet header. In practical use, the hot water flowing out of the hot water outlet header 50 flows back to the temperature control tube bundle 30 through the communication with the hot water outlet header 50, and the hot water flow is used for reversely heating the flue gas, so that the temperature of the flue gas in the coal-saving flue 20 is increased. In this application, for the inflow temperature control tube bank 30 and the inflow of better control hot water, be equipped with high temperature water valve 71 on the high temperature water guide pipeline 70. Different from the traditional existing economizer, the amount of the entering water is changed according to the load change of the boiler, and in the application, the high-temperature water valve 71 is adjusted according to the change of the exhaust gas temperature, so that the inflow and inflow of the hot water entering the temperature control tube bundle 30 are controlled.
In this application, in order to ensure the stability of the coal saving box 10, the low temperature economizer further includes a support frame for supporting the coal saving box 10.
In order to facilitate the technical solution better understood by those skilled in the art, the following further description is provided in connection with the use process of the ultrasound therapy head patch.
When the low-temperature economizer is used, when the boiler operates at rated load or high load, the slag cooling valve 61 is opened, the high-temperature water valve 71 is closed, the cooling water of the slag cooler with lower temperature is introduced into the temperature control tube bundle 30 of the low-temperature economizer, the temperature of the flue gas is reduced to 130-135 ℃ after the cooling water absorbs heat in the low-temperature economizer, and finally the cooling water enters the inlet of a No. 5 low-pressure heater of the boiler. When the boiler operates at low load, the cold slag valve 61 is closed to reduce the inflow of cold water, or the cold slag valve 61 is closed to prohibit the inflow of cold water, so that the temperature of the discharged smoke is kept at 130-135 ℃. If the temperature of the exhaust gas of the boiler is still reduced to below 130 ℃ under the condition of the closed cold slag valve 61, the high-temperature water valve 71 is opened, so that the hot water flowing out of the hot water outlet header 50 flows back to the temperature control tube bundle 30, the hot water flow is used for reversely heating the exhaust gas, the temperature of the exhaust gas in the coal-saving flue 20 is increased, and the hot water flows into the inlet of a No. 5 low-pressure heater after coming out of the low-temperature coal economizer. Of course, the inflow and outflow of hot water into the temperature-controlled tube bundle 30 can be controlled by adjusting the hot water valve 71, so as to control the temperature of the exhaust smoke of the boiler between 130 ℃ and 135 ℃.
The present application further provides a circulating fluidized bed boiler, fig. 5 is a schematic structural diagram of the circulating fluidized bed boiler of the present application, and as shown in fig. 5, the circulating fluidized bed boiler includes: a drum, a furnace water wall, a superheater, a reheater, a separator, an ash return valve, an economizer, an air preheater, a coal slurry feeding device, a valve, a DCS (Distributed Control System), and the low-temperature economizer 100 described above. It should be noted that, except for the low-temperature economizer, other components of the circulating fluidized bed boiler belong to the existing devices, and the structure and the using process of each component will not be described in detail herein
When the circulating fluidized bed boiler is started to operate, under the control of DCS, when the temperature of the exhaust smoke is lower than a preset minimum temperature (for example 130 ℃) and exceeds a preset maximum temperature (for example 135 ℃), the cold slag valve or the high-temperature water valve is automatically controlled, so that the temperature of the exhaust smoke is automatically maintained at 130 ℃ -135 ℃. The control process is the same as the adjustment process of the low-temperature economizer, and the detailed description is omitted here.
The low-temperature economizer adjusts the full-combustion coal slime, and therefore the circulating fluidized bed boiler formed by the low-temperature economizer is also suitable for the full-combustion coal slime. The low-temperature economizer can be used in parallel with the existing economizer in a circulating fluidized bed boiler, and can also be isolated and overhauled at any time. Utilize the low temperature economizer of this application, reform transform into coal-fired mud boiler unit with current coal fired boiler, improve the availability factor of boiler, also improved the economic benefits of power plant.
The low-temperature economizer and the circulating fluidized bed boiler realize the regulation and control of the exhaust gas temperature of the boiler, the exhaust gas temperature can be always kept between 130 ℃ and 135 ℃ no matter how the load of the boiler changes, the problem of blockage caused by low-temperature corrosion generated when the full-combustion coal slime boiler operates at a lower load and condensation of the low-temperature corrosion generated when the full-combustion coal slime boiler operates into water is solved, and the problem of high exhaust gas temperature generated when the full-combustion coal slime boiler operates at a high load is solved. The low-temperature economizer and the circulating fluidized bed boiler meet the requirement of a large coal slime boiler on the exhaust gas temperature, and prevent the problems that low-temperature smoke corrodes a pipeline, blocks ash and high-temperature smoke damages the boiler and influences the boiler efficiency. In addition, the low-temperature economizer is simple in structure, low in cost and simple in operation, can be used regardless of a newly-built coal slime boiler or a coal slime burning boiler transformed from an old boiler, is suitable for large-scale popularization and application, and has an obvious energy-saving effect.
The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (5)
1. A low-temperature economizer is characterized by comprising an economizer box (10), wherein an economizer flue (20) communicated with a boiler tail flue is arranged in the economizer box (10), a temperature control tube bundle (30) is arranged in the economizer flue (20), one end of the temperature control tube bundle (30) is communicated with a cold water inlet header (40), the other end of the temperature control tube bundle is communicated with a hot water outlet header (50), and the hot water outlet header (50) is communicated with an inlet end of a No. 5 low-pressure heater on a boiler;
the low-temperature economizer also comprises a cold slag guide pipeline (60) and a high-temperature water guide pipeline (70), wherein the water inlet end of the cold slag guide pipeline (60) is communicated with the outlet pipe of the slag cooler of the boiler, and the water outlet end of the cold slag guide pipeline (60) is communicated with the water flow inlet header;
the water inlet end of the high-temperature water guide pipeline (70) is communicated with the hot water outlet header (50), and the water outlet end of the high-temperature water guide pipeline (70) is communicated with the water flow inlet header.
2. The low-temperature economizer of claim 1, wherein the cold slag guiding pipe (60) is provided with a cold slag valve (61).
3. The low-temperature economizer according to claim 1, wherein a high-temperature water valve (71) is provided on the high-temperature water guide pipe (70).
4. The low-temperature economizer according to claim 1, further comprising a support frame for supporting the economizer tank (10).
5. A circulating fluidized bed boiler, comprising: the boiler comprises a drum, a furnace water wall, a superheater, a reheater, a separator, an ash return valve, an economizer, an air preheater, a coal slurry feeding device, a valve, a DCS and the low-temperature economizer of any one of claims 1 to 4.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202121492331.3U CN215336289U (en) | 2021-07-01 | 2021-07-01 | Low-temperature economizer and circulating fluidized bed boiler |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121492331.3U CN215336289U (en) | 2021-07-01 | 2021-07-01 | Low-temperature economizer and circulating fluidized bed boiler |
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| CN215336289U true CN215336289U (en) | 2021-12-28 |
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| CN202121492331.3U Active CN215336289U (en) | 2021-07-01 | 2021-07-01 | Low-temperature economizer and circulating fluidized bed boiler |
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| GR01 | Patent grant | ||
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| CP03 | Change of name, title or address |
Address after: 273500 No. 949, Fushan South Road, Zoucheng City, Jining City, Shandong Province Patentee after: Yankuang Energy Group Co.,Ltd. Patentee after: Shandong Yankuang Jisan Electric Power Co., Ltd Address before: 273500 Shandong city of Jining province Zoucheng City Fushan Road No. 298 Patentee before: YANZHOU COAL MINING Co.,Ltd. Patentee before: Shandong Yankuang Jisan Electric Power Co., Ltd |
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