Hood and circulating fluidized bed boiler

Abstract

This invention discloses a wind cap and a circulating fluidized bed boiler. The wind cap includes an outer cover and a core tube. The outer cover has a downward-opening chamber. The core tube includes an inner core tube and an outer core tube sleeved around the outer circumference of the inner core tube. The inner core tube has a flue gas inlet, and its top end extends into the chamber, with a vent hole for exhausting gas into the chamber. The outer core tube has a high-pressure gas inlet. The inner wall of the outer core tube and the outer wall of the inner core tube form an airflow channel, which communicates with the chamber through a gap. The gas flow rate in the gap is greater than the gas flow rate in the airflow channel. When the wind cap needs to be purged, high-pressure gas enters the airflow channel through the high-pressure gas inlet. The airflow entering the high-pressure gas enters the chamber through the gap, increasing the airflow velocity to purge the walls of the wind cap. Small particles are discharged through the first outlet, i.e., blown out of the wind cap, thereby reducing wind cap blockage and improving the boiler's operational safety.

Description

Technical Field

[0001] This invention relates to the field of boiler technology, and in particular to a wind cap and a circulating fluidized bed boiler. Background Technology

[0002] Traditional wind caps mainly consist of a core tube and an outer cover. Sintering flue gas enters the inside of the wind cap through the core tube and finally flows out through the side holes of the outer cover.

[0003] Because the sintering flue gas contains a large number of micron-sized iron oxide powder particles, its Taman temperature is 646℃ / 952℃. Within this range, the iron oxide powder is prone to sintering, and the sintered lumps easily block the airflow channels. The sintering flue gas also contains elements such as Cl and S, the presence of which lowers the Taman temperature of the iron oxide powder. In addition, the iron oxide powder in the sintering flue gas is micron-sized, which further reduces its Taman temperature. Sintering of the iron oxide powder will occur at 400-500℃.

[0004] Typically, after a period of operation, blockages can easily occur in areas where the gap between the outer casing and the core tube is small, leading to increased primary air pressure and reduced air volume. In severe cases, boiler shutdown and maintenance may be necessary, and blockage of the air cap reduces the operational safety of the boiler.

[0005] Therefore, how to improve the operational safety of boilers is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an air cap to improve the operational safety of a boiler. Another purpose of this invention is to provide a circulating fluidized bed boiler including the above-mentioned air cap.

[0007] The hood provided in this application includes:

[0008] An outer cover, the outer cover having a first outlet and a downward-opening chamber, the first outlet communicating with the chamber;

[0009] The core tube includes an inner core tube and an outer core tube sleeved around the outer periphery of the inner core tube. The inner core tube has a flue gas inlet, and its top end extends into the chamber and has a vent hole for exhausting gas into the chamber. The outer core tube has a high-pressure gas inlet. The inner wall of the outer core tube and the outer wall of the inner core tube form an airflow channel. The airflow channel communicates with the chamber through a gap, and the gas flow rate in the gap is greater than the gas flow rate in the airflow channel.

[0010] Optionally, in the above-mentioned wind cap, the wind cap is a one-piece molded structure, the wind cap is a fire-resistant structure, and the outer wall of the fire-resistant structure is covered with a wear-resistant layer.

[0011] Optionally, in the above-mentioned wind cap, the airflow channel is connected to the inner cavity of the inner core tube through a second outlet.

[0012] Optionally, the aforementioned hood also includes:

[0013] A first shut-off valve is disposed in the inner cavity of the inner core tube to isolate the flue gas inlet and the vent when closed;

[0014] A second shut-off valve is used to seal the gap.

[0015] Optionally, in the above-mentioned wind cap, the second shut-off valve includes a piston and a lifting device that drives the piston to move up and down, and the piston can seal the gap after entering the gap.

[0016] Optionally, in the above-mentioned vent, the inner diameter of the vent is less than or equal to 5mm, and the distance between the inner wall of the outer core tube and the outer wall of the inner core tube at the gap is 5mm-7mm.

[0017] Optionally, the above-mentioned wind cap also includes a primary air pressure sensor for the inner core tube, which is used to monitor the primary air outlet pressure.

[0018] A circulating fluidized bed boiler includes a boiler body and an air cap disposed on the boiler body, wherein the air cap is any of the air caps described above.

[0019] Optionally, the above-mentioned circulating fluidized bed boiler also includes:

[0020] The high-pressure gas inlet of the air cap is connected to the high-pressure gas outlet of the air intake pipe;

[0021] A high-pressure air storage tank, wherein the high-pressure air storage tank is connected to the high-pressure gas inlet of the air inlet pipe;

[0022] A primary air fan pressure sensor, which is used to monitor the outlet pressure of the primary air fan in real time;

[0023] The third shut-off valve is installed on the intake pipe and is located upstream of the high-pressure gas outlet of the intake pipe.

[0024] The control system includes a primary air fan pressure sensor and a third shut-off valve, both of which are connected to the control system via signal connection. When the control system receives a pressure value from the primary air fan pressure sensor that exceeds a preset multiple of the maximum value of a preset safe pressure range, it controls the third shut-off valve to open intermittently, allowing high-pressure air from the high-pressure air storage tank to enter the air cap through the air inlet pipe. The third shut-off valve is then closed when the control system receives a pressure value from the primary air fan pressure sensor that is within the preset safe pressure range.

[0025] Optionally, the circulating fluidized bed boiler described above also includes a blower for supplying gas to the high-pressure air storage tank, and the high-pressure gas inlets of the plurality of blower caps are connected in series to the high-pressure gas outlet of the air inlet pipe.

[0026] A circulating fluidized bed boiler, comprising:

[0027] Furnace body;

[0028] The air cap provided on the furnace body is the air cap described above.

[0029] The high-pressure gas inlet of the air cap is connected to the high-pressure gas outlet of the air intake pipe;

[0030] A high-pressure air storage tank, wherein the high-pressure air storage tank is connected to the high-pressure gas inlet of the air inlet pipe;

[0031] A primary air fan pressure sensor, which is used to monitor the primary air fan outlet pressure in real time;

[0032] The third shut-off valve is installed on the intake pipe and is located upstream of the high-pressure gas outlet of the intake pipe.

[0033] The control system includes a first shut-off valve, a second shut-off valve, the primary air fan pressure sensor, and a third shut-off valve, all of which are signal-connected to the control system. When the control system receives a pressure value from the primary air fan pressure sensor that exceeds the maximum safe value of a preset safe pressure range, it controls the third shut-off valve to open intermittently. While the third shut-off valve is open, the first shut-off valve is closed, and the second shut-off valve is open or intermittently open, until the control system receives a pressure value from the primary air fan pressure sensor that is within the preset safe pressure range, at which point it controls the third shut-off valve to close and the first shut-off valve to open.

[0034] Optionally, the circulating fluidized bed boiler described above also includes a blower for supplying gas to the high-pressure air storage tank, and the high-pressure gas inlets of the plurality of blower caps are connected in series to the high-pressure gas outlet of the air inlet pipe.

[0035] In the above technical solution, the wind cap provided by the present invention includes an outer cover and a core tube. The outer cover has a downward-opening chamber. The core tube includes an inner core tube and an outer core tube sleeved around the outer periphery of the inner core tube. The inner core tube has a flue gas inlet, and its top end extends into the chamber and has a vent hole for exhausting gas into the chamber. The outer core tube has a high-pressure gas inlet. The inner wall of the outer core tube and the outer wall of the inner core tube form an airflow channel. The airflow channel communicates with the chamber through a gap, and the gas flow rate in the gap is greater than the gas flow rate in the airflow channel. During installation, the high-pressure gas inlet can be connected to a pipeline for conveying high-pressure gas. When the wind cap does not need to be purged, the high-pressure gas pipeline is in a closed state. When the wind cap needs to be purged, high-pressure gas enters the airflow channel through the high-pressure gas inlet. The airflow entering the high-pressure gas enters the chamber through the gap, and the airflow speed increases to purge the wall of the wind cap, discharging small particles through the first outlet, i.e., blowing them out of the wind cap, thereby reducing the possibility of wind cap blockage and improving the operating safety of the boiler. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of the wind cap provided in an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of the structure of a circulating fluidized bed boiler provided in an embodiment of the present invention.

[0039] in Figure 1-2 middle:

[0040] 1-Outer cover, 2-Inner core tube, 3-Outer core tube, 4-Primary air fan pressure sensor, 5-First shut-off valve, 6-Second shut-off valve, 7-Vent hole, 8-First outlet, 9-Second outlet, 10-High-pressure gas inlet, 11-Gap, 12-Wind cap, 13-High-pressure air storage tank, 14-Inlet pipe, 15-Fan, 16-Control system, 17-Primary air fan, 18-Third shut-off valve, 19-Flue gas inlet. Detailed Implementation

[0041] The core of this invention is to provide an air cap to improve the safety of boiler operation. Another core aspect of this invention is to provide a circulating fluidized bed boiler including the above-mentioned air cap.

[0042] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] Please refer to Figure 1 and Figure 2 .

[0044] In one specific embodiment, the wind cap provided by this invention includes an outer cover 1 and a core tube. The outer cover 1 has a downward-opening chamber. The core tube includes an inner core tube 2 and an outer core tube 3 sleeved around the outer periphery of the inner core tube 2. Both the inner core tube 2 and the outer core tube 3 are fixedly connected to the outer cover 1. To improve assembly efficiency, the wind cap 12 is preferably an integrally formed structure. The inner core tube 2 is provided with a flue gas inlet 19, which is preferably located at the bottom end of the inner core tube 2 and opens downward to facilitate the entry of flue gas from the furnace into the inner core tube 2. The top end of the inner core tube 2 extends into the chamber and is provided with a vent hole 7 for exhausting gas into the chamber. Specifically, multiple vent holes 7 can be arranged around the inner core tube 2, and preferably, the spacing between adjacent vent holes 7 is equal.

[0045] The outer core tube 3 is provided with a high-pressure gas inlet 10. Specifically, the high-pressure gas inlet 10 can be located on the side wall of the outer core tube 3. The inner wall of the outer core tube 3 and the outer wall of the inner core tube 2 form an airflow channel. Preferably, the airflow channel is annular, for example, circular. The airflow channel communicates with the chamber through a gap 11. The gas flow rate in the gap 11 is greater than the gas flow rate in the airflow channel. Specifically, the gap 11 can be annular, formed by the inner wall of the outer core tube 3 and the outer wall of the inner core tube 2.

[0046] like Figure 1 As shown, the slit 11 can be located at the bottom of the chamber, and the gas is ejected upward through the slit 11. Of course, the core tube is not limited to the structure shown in the figure. The core tube can also be lengthened, for example, the core tube can be extended to the top of the chamber, the slit 11 opens downward, and the gas is ejected downward through the slit 11, so that the high-pressure air blows the chamber from top to bottom.

[0047] In practical use, the wind cap 12 is fixed to the air distribution plate, and the number of wind caps 12 on the air distribution plate depends on the needs.

[0048] During installation, the high-pressure gas inlet 10 can be connected to a pipeline for conveying high-pressure gas. When purging the vent cap 12 is not required, the high-pressure gas pipeline is closed. When purging the vent cap 12 is required, high-pressure gas enters the airflow channel through the high-pressure gas inlet 10. The airflow then enters the chamber through the gap 11, increasing the airflow velocity to purge the walls of the vent cap 12, especially the first outlet. This purges small particles through the first outlet 8, effectively blowing them out of the vent cap 12, thereby reducing the likelihood of blockage and improving the boiler's operational safety.

[0049] Meanwhile, by reducing the blockage of the air cap 12, the operating time of the sintering flue gas circulating fluidized bed boiler was increased, the number of boiler shutdowns for maintenance was reduced, and the economic benefits of the enterprise were improved.

[0050] Specifically, the wind cap 12 has an iron shell. Since the temperature inside a circulating fluidized bed boiler is generally 800℃-900℃, while the temperature inside the wind cap 12 can reach 600℃-700℃, iron oxide powder is easily sintered at this temperature. Preferably, the wind cap 12 can be a refractory structure that is not easily sintered. Furthermore, in this invention, the outer shell of the outer cover 1 is made of iron, and the inner side of the wind cap 12 is cast with a low thermal conductivity refractory material. The outer wall of the refractory structure is covered with a wear-resistant layer. When the wear-resistant layer is on the iron shell, the iron shell is treated with wear-resistant material, effectively extending the service life of the wind cap 12. Specifically, the refractory structure is made of a low thermal conductivity refractory material, which reduces the temperature inside the wind cap 12 and reduces the sintering of iron oxide powder.

[0051] In one specific embodiment, the airflow channel is connected to the inner cavity of the inner core tube 2 through the second outlet 9. Specifically, the second outlet 9 can be arranged in a ring shape. By setting the second outlet 9, high-pressure gas can enter the inner core tube 2 through the second outlet 9 and then purge the inner wall of the inner core tube 2, further reducing the blockage of the wind cap 12.

[0052] In one specific embodiment, the wind cap 12 further includes a first shut-off valve 5 and a second shut-off valve 6. The first shut-off valve 5 is disposed in the inner cavity of the inner core tube 2 to isolate the flue gas inlet 19 and the vent 7 when closed. When the first shut-off valve 5 is closed, it prevents high-pressure gas from flowing into the furnace body through the flue gas inlet 19. Specifically, the first shut-off valve 5 is located between the flue gas inlet 19 and the second outlet 9.

[0053] The second shut-off valve 6 is used to seal the gap 11. The first shut-off valve 5 and the second shut-off valve 6 can be controlled by an external signal from the operator. In specific opening and closing actions, the first shut-off valve 5 and the second shut-off valve 6 are each equipped with an electric drive mechanism. For example, a servo motor drives the sealing parts of the first shut-off valve 5 and the second shut-off valve 6 to move up and down or rotate to achieve the opening and closing of the corresponding positions.

[0054] In one specific embodiment, the second shut-off valve 6 includes a piston and a lifting device that drives the piston to move up and down. After the piston enters the gap 11, it seals the gap 11. Specifically, when the piston slides into the gap 11, the side wall of the piston slides and seals with the gap 11.

[0055] In one specific embodiment, the inner diameter of the vent 7 is less than or equal to 5 mm, and the inner diameter of the vent 7 is 2 mm to 4 mm. In this invention, the inner diameter of the vent 7 ensures that the sintering flue gas flows out of the inner core tube 2 at a speed of 50 m / s to 60 m / s.

[0056] The distance between the inner wall of the outer core tube 3 and the outer wall of the inner core tube 2 at the gap 11 is 5mm-7mm. For example, the distance between the inner wall of the outer core tube 3 and the outer wall of the inner core tube 2 at the gap 11 is 6mm. This ensures that the flow velocity of the sintering flue gas in the slit is not less than 50m / s, preventing dust accumulation due to insufficient velocity. The jet velocity of high-pressure air through the gap 11 is not less than 90m / s.

[0057] like Figure 1 As shown, the air cap 12 also includes a primary air fan pressure sensor 4 disposed on the inner core tube 2. The primary air fan pressure sensor 4 can be installed on the inner core tube 2 and is connected to the display signal. The primary air fan pressure sensor 4 can monitor the outlet pressure of the primary air fan 17 in real time, that is, the flue gas inlet 19 pressure of the furnace body and the air cap 12, so that the staff can know in time whether the air cap 12 is blocked, and then determine whether it is necessary to introduce high-pressure gas into the air cap 12 for purging.

[0058] This application provides a circulating fluidized bed boiler comprising a furnace body and an air cap disposed on the furnace body, wherein the air cap is any of the aforementioned types. The specific structure of the air cap has been described above; this application includes the aforementioned air cap and also achieves the aforementioned technical effects.

[0059] like Figure 2 As shown, in one specific embodiment, the circulating fluidized bed boiler further includes an inlet pipe 14, a high-pressure air storage tank 13, a primary air fan pressure sensor 4, a third shut-off valve 18, and a control system 16. The high-pressure gas inlet 10 of the air cap 12 is connected to the high-pressure gas outlet of the inlet pipe 14; the high-pressure air storage tank 13 is connected to the high-pressure gas inlet of the inlet pipe 14; the primary air fan pressure sensor 4 is used to monitor the outlet pressure of the primary air fan 17 in real time, and the primary air fan pressure sensor 4 can be installed at the outlet position of the primary air fan 17; the third shut-off valve 18 is installed on the inlet pipe 14 and is located upstream of the high-pressure gas outlet of the inlet pipe 14. The primary air fan pressure sensor 4 and the third shut-off valve 18 are signal-connected to the control system 16.

[0060] As the operating time of the circulating fluidized bed boiler increases, the blockage inside the air cap 12 gradually worsens, leading to a decrease in the oxygen concentration inside the furnace, necessitating an increase in the primary air pressure. When the control system 16 receives a pressure value from the primary air fan pressure sensor 4 exceeding 105%-110% of the maximum preset safe pressure range, it controls the third shut-off valve 18 to open intermittently. High-pressure air from the high-pressure air storage tank 13 enters the air cap 12 through the inlet pipe 14. The opening time of the third shut-off valve 18 each time and the time interval between two openings of the third shut-off valve 18 are determined as needed and are not specifically limited in this application.

[0061] Specifically, when the third shut-off valve 18 is open, the control system 16 controls the first shut-off valve 5 to close and the second shut-off valve 6 to open, at which time high-pressure gas purges the air cap 12. Of course, to avoid frequent opening and closing of the shut-off valves and the second shut-off valve 6, the control system 16 always controls the first shut-off valve 5 to close and the second shut-off valve 6 to open when the pressure value of the primary air blower pressure sensor 4 exceeds a preset multiple of the maximum value of the preset safe pressure range. When the pressure value of the primary air blower pressure sensor 4 is less than a preset multiple of the preset safe pressure range, the control system 16 controls the first shut-off valve 5 to open and the second shut-off valve 6 to close. When the control system 16 receives a pressure value from the primary air blower pressure sensor 4 within the preset safe pressure range, it controls the third shut-off valve 18 to close and the first shut-off valve 5 to open, at which time the second shut-off valve 6 can be in the closed state.

[0062] For example, the primary blower pressure sensor 4 monitors the pressure changes at the sintering flue gas inlet 19 in real time. The pressure at the flue gas inlet 19 is the outlet pressure of the primary blower 17. For instance, when the pressure at the flue gas inlet 19 reaches 110% of the preset safe pressure range, the control system 16 controls the first shut-off valve 5 and the second shut-off valve 6 to operate. Specifically, the servo motor receives a signal from the control system 16 and begins to operate: firstly, the first shut-off valve 5 closes, closing the channel for the sintering flue gas to enter the air cap 12; simultaneously, the third shut-off valve 18 opens intermittently; and the piston of the second shut-off valve 6 moves downward under the drive of the servo motor. At this time, both the slit 11 and the second outlet 9 are open, allowing high-pressure air to enter the chamber through the slit 11 and the vent 7 for purging. After a preset purging time, such as 30-40 seconds, the piston moves upward to the position of the slit 11, sealing the slit 11. At this time, high-pressure air only enters through the second outlet 9, purging the chamber from top to bottom and blowing small particles out of the air cap 12.

[0063] To facilitate the delivery of gas to the high-pressure air storage tank 13, preferably, the circulating fluidized bed boiler is also equipped with a blower 15. Specifically, when the blower 15 delivers gas to the high-pressure air storage tank 13, and the pressure in the high-pressure air storage tank 13 reaches a preset pressure, the blower 15 stops working, and the high-pressure air storage tank 13 stores high-pressure air.

[0064] In one specific embodiment, the high-pressure gas inlets 10 of multiple air caps 12 are connected in series to the high-pressure gas outlet of the air inlet pipe 14, so as to realize high-pressure purging of multiple air caps 12 at the same time and improve the purging efficiency of the circulating fluidized bed boiler.

[0065] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not 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

1. A hood, characterized in that, include: The outer cover (1) is provided with a first outlet and a downward-opening chamber, and the first outlet is connected to the chamber; The core tube includes an inner core tube (2) and an outer core tube (3) sleeved around the outer periphery of the inner core tube (2). The inner core tube (2) is provided with a flue gas inlet (19). The top end of the inner core tube (2) extends into the chamber and is provided with a vent hole (7) for exhausting gas into the chamber. The outer core tube (3) is provided with a high-pressure gas inlet (10). The inner wall of the outer core tube (3) and the outer wall of the inner core tube (2) form an airflow channel. The airflow channel communicates with the chamber through a gap (11). The gas flow rate in the gap (11) is greater than the gas flow rate in the airflow channel.

2. The hood according to claim 1, characterized in that, The wind cap (12) is an integrally formed structure. The wind cap (12) is a fire-resistant structure, and the outer wall of the fire-resistant structure is covered with a wear-resistant layer.

3. The hood according to claim 1, characterized in that, The airflow channel is connected to the inner cavity of the inner core tube (2) through the second outlet (9).

4. The hood according to claim 1, characterized in that, Also includes: The first shut-off valve (5) is disposed in the inner cavity of the inner core tube (2) to isolate the flue gas inlet (19) and the vent (7) when closed. The second shut-off valve (6) is used to seal the gap (11).

5. The hood according to claim 4, characterized in that, The second shut-off valve (6) includes a piston and a lifting device that drives the piston to move up and down. After the piston enters the gap (11), it can seal the gap (11).

6. The hood according to claim 1, characterized in that, The inner diameter of the vent (7) is less than or equal to 5 mm, and the distance between the inner wall of the outer core tube (3) and the outer wall of the inner core tube (2) at the gap (11) is 5 mm to 7 mm.

7. The hood according to claim 1, characterized in that, It also includes a primary air pressure sensor (4) disposed in the inner core tube (2), the primary air pressure sensor (4) being used to monitor the outlet pressure of the primary air fan (17).

8. A circulating fluidized bed boiler, characterized in that, It includes a furnace body and an air cap disposed on the furnace body, wherein the air cap is the air cap (12) according to any one of claims 1-7.

9. The circulating fluidized bed boiler according to claim 8, characterized in that, Also includes: The high-pressure gas inlet (10) of the wind cap (12) is connected to the high-pressure gas outlet of the air inlet (14); High-pressure air storage tank (13), the high-pressure air storage tank (13) is connected to the high-pressure gas inlet of the air inlet pipe (14); A primary air fan pressure sensor (4) is used to monitor the outlet pressure of the primary air fan (17) in real time. The third shut-off valve (18) is installed on the air inlet pipe (14) and is located upstream of the high-pressure gas outlet of the air inlet pipe (14). The control system (16) is connected to the primary air fan pressure sensor (4) and the third shut-off valve (18). When the control system (16) receives the pressure value of the primary air fan pressure sensor (4) which exceeds the preset multiple of the maximum value of the preset safe pressure range, it controls the third shut-off valve (18) to open intermittently. The high-pressure air in the high-pressure air storage tank (13) enters the air cap (12) through the air inlet pipe (14) until the control system (16) receives the pressure value of the primary air fan pressure sensor (4) which is within the preset safe pressure range, and then controls the third shut-off valve (18) to close.

10. The circulating fluidized bed boiler according to claim 9, characterized in that, It also includes a blower (15) for supplying gas to the high-pressure air storage tank (13), and the high-pressure gas inlets (10) of the plurality of air caps (12) are connected in series to the high-pressure gas outlet of the air inlet pipe (14).

11. A circulating fluidized bed boiler, characterized in that, include: Furnace body; The air cap provided on the furnace body is the air cap (12) as described in claim 4. The high-pressure gas inlet (10) of the wind cap (12) is connected to the high-pressure gas outlet of the air inlet (14); High-pressure air storage tank (13), the high-pressure air storage tank (13) is connected to the high-pressure gas inlet of the air inlet pipe (14); A primary air fan pressure sensor (4) is used to monitor the outlet pressure of the primary air fan (17) in real time. The third shut-off valve (18) is installed on the air inlet pipe (14) and is located upstream of the high-pressure gas outlet of the air inlet pipe (14). The control system (16), the first shut-off valve (5), the second shut-off valve (6), the primary air fan pressure sensor (4), and the third shut-off valve (18) are all signal connected to the control system (16). When the control system (16) receives the pressure value of the primary air fan pressure sensor (4) which is greater than the maximum safe value of the preset safe pressure range, it controls the third shut-off valve (18) to open intermittently. When the third shut-off valve (18) is open, the first shut-off valve (5) is closed, and the second shut-off valve (6) is open or intermittently open, until the control system (16) receives the pressure value of the primary air fan pressure sensor (4) which is within the preset safe pressure range, it controls the third shut-off valve (18) to close and the first shut-off valve (5) to open.

12. The circulating fluidized bed boiler according to claim 11, characterized in that, It also includes a blower (15) for supplying gas to the high-pressure air storage tank (13), and the high-pressure gas inlets (10) of the plurality of air caps (12) are connected in series to the high-pressure gas outlet of the air inlet pipe (14).

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