Electricity-saving fluidized bed furnace air inlet control device and method

Abstract

The invention discloses an electricity-saving fluidized bed furnace air inlet control device and method, and the device comprises a furnace body, and the bottom of the inner side of the furnace body is provided with an air cap used for air inlet; the air bellow is fixed at the lower end of the furnace body to be communicated with the interior of the air cap; the fan is arranged on one side of the furnace body, and an air outlet of the fan is connected with a communicating pipe connected with the air bellow; the air guide pipe is arranged on the lower surface of the communicating pipe; the air storage tank is connected to one end of the air guide pipe; through the arrangement of the air storage tank, the sensor, the air guide pipe, the first air outlet pipe and the first control valve, the device can operate the fan at constant power, energy consumption caused by frequent power adjustment of the fan is reduced, then air is stored in the inner side of the air storage tank so that air entering the inner side of the furnace body can be automatically adjusted during fuel adjustment, energy consumption can be reduced, and the service life of the furnace body is prolonged. And by arranging the air inlet assembly, waste heat at the slag discharging position can be recycled conveniently, and heat waste during slag discharging is avoided.

Description

Technical Field

[0001] This invention specifically relates to an energy-saving fluidized bed furnace air intake control device and method. Background Technology

[0002] Fluidized bed combustion furnaces, as highly efficient combustion equipment, are widely used in industries such as chemical, metallurgical, and energy. Their working principle involves a high-speed airflow introduced into the furnace through a bottom vent cap. With the aid of a combustion fan, coal particles are added at a uniform speed. The red-hot sand particles inside the furnace ignite the added coal particles, causing them to boil together, thus achieving complete combustion and efficient heat transfer. Traditional fluidized bed combustion furnaces often rely on direct adjustment of the airflow by the fan. When the fuel input changes, the airflow is typically altered by adjusting the fan speed to meet the oxygen demand at different combustion stages.

[0003] However, existing methods for regulating fan speed have significant drawbacks: on the one hand, frequent start-stop or variable speed operation of the fan leads to increased energy consumption; on the other hand, the air supply response is delayed, making it difficult to match changes in fuel input in real time, which can easily cause momentary oxygen deficiency affecting combustion, or excessive air supply leading to high energy consumption. In addition, the waste residue generated by the fluidized bed furnace during operation, such as coal gangue, is usually discharged directly through the slag discharge pipe, and the sand particles and high-temperature waste heat carried in it are often not effectively recovered. Therefore, we propose an energy-saving fluidized bed furnace air intake control device and method. Summary of the Invention

[0004] The purpose of this invention is to provide an energy-saving fluidized bed furnace air intake control device and method to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an energy-saving fluidized bed furnace air intake control device, comprising:

[0006] The furnace body has an air hood installed at the bottom of its inner side for air intake;

[0007] The bellows is fixed to the lower end of the furnace body to communicate with the inside of the bellows cap;

[0008] A blower is installed on one side of the furnace body, and the blower outlet is connected to a connecting pipe that is connected to the air box;

[0009] A duct is disposed on the lower surface of the connecting pipe;

[0010] A gas storage tank is connected to one end of the air duct, and one end of the gas storage tank has a first air outlet pipe that communicates with the air box, and the first air outlet pipe has a first control valve.

[0011] The sensor is connected to one side of the first control valve via a wire, and the sensor is in conjunction with the fuel inlet of the furnace body. When fuel is detected being added, the sensor transmits a signal to adjust the opening of the first control valve.

[0012] Preferably, the air duct has an inclined structure, and a one-way valve is fitted on the outside of the air duct.

[0013] Preferably, the sensor is a proximity sensor, the first control valve has a controller, and the controller is electrically connected to the sensor.

[0014] Preferably, the blower inlet is connected to a first air inlet pipe, the top of the first air inlet pipe is provided with a three-way valve, one port of the three-way valve is connected to an air inlet assembly, and the air inlet assembly is connected to a slag discharge pipe provided on one side wall of the furnace body to recover sand particles and waste heat, and the other port of the three-way valve is connected to a second air inlet pipe.

[0015] Preferably, the air inlet assembly includes a bend, a suction pipe, a filter cover, and a second filter screen. The bend is fixed to a three-way valve, and a filter cylinder is connected to the lower end of the bend. The filter cover is fixed inside the filter cylinder to correspond to the end of the bend. The lower end of the filter cylinder has a connection port. A suction pipe with both ends connected to the filter cylinder and the slag discharge pipe is provided between the filter cylinder and the slag discharge pipe. The inner wall of the slag discharge pipe has a second filter screen corresponding to the end of the suction pipe.

[0016] Preferably, the air intake assembly further includes a first filter screen, a first feed pipe, and a second control valve. The first feed pipe is connected to the inside of the connection port, and one end of the first feed pipe is connected to the inside of the air box. A second control valve is installed on one side of the first feed pipe. The first filter screen is fixed to the upper part of the inside of the air box to correspond to one end of the first feed pipe.

[0017] Preferably, the height of the edge of the first filter screen is greater than the height of one end of the connecting pipe and the first air outlet pipe.

[0018] Preferably, the air inlet assembly further includes a second feeding pipe, a third control valve, and a second air outlet pipe. The second feeding pipe is connected to the inside of the connection port, and one end of the second feeding pipe is connected to the inside of the furnace body. A third control valve is installed on the second feeding pipe. The second air outlet pipe is fixed to the lower end of one side wall of the bend, and one end of the second air outlet pipe is connected to the inside of the gas storage tank. A second solenoid valve is provided on the second air outlet pipe.

[0019] A method for controlling the air intake of an energy-saving fluidized bed furnace, using the aforementioned control device, further includes the following steps:

[0020] Step A: The blower blows air into the inside of the air box through the connecting pipe. The air enters the inside of the furnace body through the air cap to assist combustion and suspend the fuel. At the same time, some air enters the inside of the air storage tank through the air guide pipe for storage.

[0021] Step B: When fuel is added to the inside of the furnace through the fuel inlet, the sensor detects the fuel and then transmits the signal to the first control valve. The first control valve adjusts the opening to increase so that air flows into the inside of the air box through the first air outlet pipe, thereby increasing the amount of air flowing into the inside of the furnace. After the sensor detects that no fuel has been added for a period of time, the connection between the first air outlet pipe and the air box is disconnected through the first control valve.

[0022] Step C: When the furnace body discharges slag to the outside through the slag discharge pipe, the three-way valve controls the connection between the bend pipe and the first air inlet pipe. Suction is generated inside the filter cylinder, and the sand particles inside the slag discharge pipe are sucked into the filter cylinder through the suction pipe. The coal gangue falls down the slag discharge pipe by its own gravity and is discharged. The filter cover isolates the sand particles inside the filter cylinder. The heat of the sand is introduced into the connecting pipe through the bend pipe, the first air inlet pipe and the fan, and then enters the air box.

[0023] Step D: When the three-way valve controls the connection between the second air inlet pipe and the first air inlet pipe, the second control valve connects the first feeding pipe to the inside of the air box, so that the sand particles flow into the inside of the air box along the inclined first feeding pipe under the action of gravity. The air flowing into the inside of the air box through the connecting pipe blows the sand particles into the inside of the furnace body again for replenishment.

[0024] Preferably, step D is replaced by: when the three-way valve controls the second air inlet pipe to connect with the first air inlet pipe, the third control valve connects the second feeding pipe to the inside of the furnace body, and at the same time the second solenoid valve controls the second air outlet pipe to connect with the inside of the gas storage tank. The high-pressure gas inside the gas storage tank is blown into the filter cylinder and the inside of the second feeding pipe through the bend pipe, so that the sand particles are reintroduced into the inside of the furnace body for replenishment.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention, by incorporating a gas storage tank, sensor, air duct, first air outlet pipe, and first control valve, avoids the energy consumption caused by excessive airflow from traditional fans and the insufficient airflow into the furnace body due to low airflow, which is detrimental to complete fuel combustion. This device can operate the fan at a constant power, reducing energy consumption caused by frequent power adjustments. By storing air inside the gas storage tank, the airflow into the furnace body is automatically adjusted during fuel adjustments, further reducing energy consumption and ensuring complete fuel combustion or suspension. The simple structure increases the practicality of the device. The inclusion of an air inlet component facilitates the recovery and utilization of waste heat at the slag discharge point, preventing heat waste during slag discharge. Furthermore, the heat recovery process effectively returns sand particles to the furnace body, reducing waste caused by sand particles discharged with coal gangue, thus reducing costs and increasing the economic benefits of the device. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention;

[0028] Figure 2 This is a schematic cross-sectional view of the bellows structure of the present invention;

[0029] Figure 3 This is a schematic diagram of the bent pipe installation structure of the present invention;

[0030] Figure 4 This is a schematic diagram of the air intake assembly structure of the present invention;

[0031] Figure 5 This is a cross-sectional view of the filter cartridge structure of the present invention;

[0032] Figure 6 This is a schematic diagram of the connection structure between the filter cylinder and the slag discharge pipe of the present invention;

[0033] Figure 7 This is a schematic diagram of the second feeding tube structure of the present invention.

[0034] In the diagram: 1. Furnace body; 2. Air box; 3. Gas storage tank; 4. Blower; 5. Sensor; 6. Connecting pipe; 7. Air guide pipe; 71. One-way valve; 9. First air outlet pipe; 91. First control valve; 10. Air cap; 11. First air inlet pipe; 12. Three-way valve; 131. Bend; 132. First filter screen; 133. Filter cylinder; 134. Suction pipe; 135. Filter cover; 136. Connection port; 137. First feeding pipe; 138. Second control valve; 139. Second filter screen; 140. Second feeding pipe; 141. Third control valve; 142. Second air outlet pipe; 14. Slag discharge pipe. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] Please see Figures 1-6 The present invention provides a technical solution: an energy-saving fluidized bed furnace air intake control device, comprising:

[0038] Furnace body 1, with an air cap 10 for air intake installed at the bottom inner side of furnace body 1;

[0039] The bellows 2 is fixed to the lower end of the furnace body 1 to communicate with the inside of the bellows 10;

[0040] The blower 4 is located on one side of the furnace body 1, and the air outlet of the blower 4 is connected to a connecting pipe 6 that is connected to the air box 2.

[0041] Air duct 7 is located on the lower surface of connecting pipe 6;

[0042] The gas storage tank 3 is connected to one end of the air duct 7, and one end of the gas storage tank 3 has a first air outlet pipe 9 connected to the air box 2, and the first air outlet pipe 9 has a first control valve 91.

[0043] This facilitates the storage of more air, so as to increase the amount of air entering the inside of the furnace body 1 when pulverized coal fuel is added to the inside of the furnace body 1.

[0044] Sensor 5 is connected to one side of the first control valve 91 via a wire, and sensor 5 is matched with the fuel inlet of the furnace body 1. When fuel is detected being added, a signal is transmitted to adjust the opening of the first control valve 91.

[0045] By setting up an automatic air conditioning system that links the gas storage tank 3 with the sensor 5, the fan 4 can operate at a constant power, avoiding energy consumption and equipment damage caused by frequent adjustments. The system automatically increases the air intake during feeding to ensure complete combustion and suspension of fuel, thereby improving combustion efficiency and stability. The overall structure is simple and highly practical.

[0046] Preferably, the air duct 7 has an inclined structure, and a one-way valve 71 is fitted on the outside of the air duct 7;

[0047] It can guide the airflow smoothly into the gas storage tank 3 and prevent gas backflow, thereby improving gas storage efficiency and system stability.

[0048] Preferably, sensor 5 is a proximity sensor, and the first control valve 91 has a controller, and the controller is electrically connected to sensor 5;

[0049] The first control valve 91 also has an actuator to automatically adjust its opening degree according to the controller signal, which facilitates real-time detection of the feeding signal and precise automatic adjustment of the air intake, resulting in rapid response and improved system automation level and control accuracy.

[0050] Preferably, the air inlet of the blower 4 is connected to a first air inlet pipe 11, and a three-way valve 12 is provided at the top of the first air inlet pipe 11. One port of the three-way valve 12 is connected to an air inlet assembly, and the air inlet assembly is connected to a slag discharge pipe 14 provided on one side wall of the furnace body 1 to recover sand particles and waste heat. The other port of the three-way valve 12 is connected to a second air inlet pipe.

[0051] The three-way valve 12 is used to adjust the air source during air intake, which facilitates the recovery and utilization of sand particles and waste heat during slag discharge, improves energy utilization efficiency, and reduces resource waste.

[0052] Preferably, the air inlet assembly includes a bend 131, an air intake pipe 134, a filter cover 135, and a second filter screen 139. The bend 131 is fixed to the three-way valve 12. The lower end of the bend 131 is connected to a filter cylinder 133. The filter cover 135 is fixed inside the filter cylinder 133 to correspond to the end of the bend 131. The lower end of the filter cylinder 133 has a connection port 136. An air intake pipe 134 with both ends connected to the filter cylinder 133 and the slag discharge pipe 14 is provided between the filter cylinder 133 and the slag discharge pipe 14. The inner wall of the slag discharge pipe 14 and the end of the air intake pipe 134 are respectively provided with a second filter screen 139.

[0053] The filter cover 135 can keep the sand particles inside the filter cylinder 133, preventing them from entering the fan 4 and protecting the equipment; the suction pipe 134 works in conjunction with the second filter screen 139 to allow the sand particles to enter the filter cylinder 133, preventing coal gangue from accidentally entering the filter cylinder 133 and achieving efficient recovery of heat and sand particles.

[0054] Preferably, the air intake assembly further includes a first filter screen 132, a first feed pipe 137, and a second control valve 138. The first feed pipe 137 is connected to the inside of the connection port 136, and one end of the first feed pipe 137 is connected to the inside of the air box 2. The second control valve 138 is installed on one side of the first feed pipe 137. The first filter screen 132 is fixed to the upper inside of the air box 2 to correspond to one end of the first feed pipe 137.

[0055] The first feeding pipe 137 and the second control valve 138 enable the controlled return of sand particles to the furnace body 1, replenishing the bed material, reducing sand particle loss, and lowering costs.

[0056] Preferably, the height of the edge of the first filter screen 132 is greater than the height of one end of the connecting pipe 6 and the first air outlet pipe 9;

[0057] The high-speed airflow flowing into the inside of the air box 2 through the connecting pipe 6 and the first air outlet pipe 9 is convenient to blow the sand particles back to the inside of the furnace body 1. Furthermore, a separate pipe can also be set between the air box 2 and the furnace body 1 so that when adding sand particles to the furnace body 1, the sand particles can enter the furnace body 1 without passing through the air cap 10.

[0058] Preferably, the air inlet assembly further includes a second feeding pipe 140, a third control valve 141, and a second air outlet pipe 142. The second feeding pipe 140 is connected to the inside of the connection port 136, and one end of the second feeding pipe 140 is connected to the inside of the furnace body 1. The third control valve 141 is installed on the second feeding pipe 140. The second air outlet pipe 142 is fixed to the lower end of one side wall of the bend pipe 131, and one end of the second air outlet pipe 142 is connected to the inside of the gas storage tank 3. The second air outlet pipe 142 has a second solenoid valve.

[0059] The high-pressure airflow inside the gas storage tank 3 is used to backflush the filter cylinder 133, so that the sand particles inside the filter cylinder 133 enter the inside of the furnace body 1 through the second feeding pipe 140 to replenish the sand particles inside the furnace body 1.

[0060] A method for controlling the air intake of an energy-saving fluidized bed furnace, employing a control device, further includes the following steps:

[0061] Step A: The blower 4 blows air into the inside of the air box 2 through the connecting pipe 6. The air enters the inside of the furnace body 1 through the air cap 10 to assist combustion and suspend the fuel. At the same time, a portion of the air enters the inside of the air storage tank 3 through the air guide pipe 7 for storage.

[0062] Step B: When fuel is added to the inside of the furnace body 1 through the fuel port, the sensor 5 detects the fuel and then transmits the signal to the first control valve 91. The first control valve 91 adjusts the opening to increase so that air flows into the inside of the air box 2 through the first air outlet pipe 9, thereby increasing the amount of air flowing into the inside of the furnace body 1. After the sensor 5 detects that no fuel has been added for a period of time, the first control valve 91 disconnects the connection between the first air outlet pipe 9 and the air box 2.

[0063] Step C: When the furnace body 1 discharges slag to the outside through the slag discharge pipe 14, the three-way valve 12 controls the connection between the bend pipe 131 and the first air inlet pipe 11. The inside of the filter cylinder 133 generates suction, and the sand particles inside the slag discharge pipe 14 are sucked into the inside of the filter cylinder 133 through the suction pipe 134. The coal gangue falls down along the slag discharge pipe 14 by its own gravity and is discharged. The filter cover 135 isolates the sand particles inside the filter cylinder 133. The heat of the sand is introduced into the inside of the connecting pipe 6 through the bend pipe 131, the first air inlet pipe 11 and the blower 4, and then enters the air box 2.

[0064] Step D: When the three-way valve 12 controls the second air inlet pipe to connect with the first air inlet pipe 11, the second control valve 138 connects the first feeding pipe 137 with the inside of the air box 2, so that the sand particles flow into the inside of the air box 2 along the inclined first feeding pipe 137 under the action of gravity. The air flowing into the inside of the air box 2 through the connecting pipe 6 blows the sand particles into the inside of the furnace body 1 again for replenishment.

[0065] Example 2

[0066] Please see Figures 1-5 , Figure 7 The present invention provides a technical solution: an energy-saving fluidized bed furnace air intake control device is the same as that in Embodiment 1.

[0067] A method for controlling the air intake of an energy-saving fluidized bed furnace, employing a control device, further includes the following steps:

[0068] Step A: The blower 4 blows air into the inside of the air box 2 through the connecting pipe 6. The air enters the inside of the furnace body 1 through the air cap 10 to assist combustion and suspend the fuel. At the same time, a portion of the air enters the inside of the air storage tank 3 through the air guide pipe 7 for storage.

[0069] Step B: When fuel is added to the inside of the furnace body 1 through the fuel port, the sensor 5 detects the fuel and then transmits the signal to the first control valve 91. The first control valve 91 adjusts the opening to increase so that air flows into the inside of the air box 2 through the first air outlet pipe 9, thereby increasing the amount of air flowing into the inside of the furnace body 1. After the sensor 5 detects that no fuel has been added for a period of time, the first control valve 91 disconnects the connection between the first air outlet pipe 9 and the air box 2.

[0070] Step C: When the furnace body 1 discharges slag to the outside through the slag discharge pipe 14, the three-way valve 12 controls the connection between the bend pipe 131 and the first air inlet pipe 11. The inside of the filter cylinder 133 generates suction, and the sand particles inside the slag discharge pipe 14 are sucked into the inside of the filter cylinder 133 through the suction pipe 134. The coal gangue falls down along the slag discharge pipe 14 by its own gravity and is discharged. The filter cover 135 isolates the sand particles inside the filter cylinder 133. The heat of the sand is introduced into the inside of the connecting pipe 6 through the bend pipe 131, the first air inlet pipe 11 and the fan 4.

[0071] Step D: When the three-way valve 12 controls the second air inlet pipe to connect with the first air inlet pipe 11, the third control valve 141 connects the second feeding pipe 140 with the inside of the furnace body 1. At the same time, the second solenoid valve controls the second air outlet pipe 142 to connect with the inside of the gas storage tank 3. The high-pressure gas inside the gas storage tank 3 is blown into the filter cylinder 133 and the inside of the second feeding pipe 140 through the bend pipe 131, so that the sand particles are fed into the inside of the furnace body 1 again for replenishment.

[0072] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An energy-saving fluidized bed furnace air inlet control device, characterized in that, include: Furnace body (1), with an air cap (10) for air intake provided on the bottom inner side of the furnace body (1); The bellows (2) is fixed to the lower end of the furnace body (1) to communicate with the inside of the bellows cap (10); A blower (4) is located on one side of the furnace body (1), and the outlet of the blower (4) is connected to a connecting pipe (6) that is connected to the air box (2). Air duct (7) is disposed on the lower surface of the connecting pipe (6); An air storage tank (3) is connected to one end of the air duct (7), and one end of the air storage tank (3) has a first air outlet pipe (9) connected to the air box (2), and the first air outlet pipe (9) has a first control valve (91). The sensor (5) is connected to one side of the first control valve (91) by a wire, and the sensor (5) is matched with the fuel inlet of the furnace body (1). When fuel is detected, the sensor transmits a signal to adjust the opening of the first control valve (91).

2. The energy-saving fluidized bed furnace air inlet control device according to claim 1, characterized in that: The air duct (7) has an inclined structure, and a one-way valve (71) is fitted on the outside of the air duct (7).

3. The energy-saving fluidized bed furnace air intake control device according to claim 1, characterized in that: The sensor (5) is a proximity sensor, and the first control valve (91) has a controller, which is electrically connected to the sensor (5).

4. The energy-saving fluidized bed furnace air inlet control device according to claim 1, characterized in that: The air inlet of the blower (4) is connected to a first air inlet pipe (11), and a three-way valve (12) is provided at the top of the first air inlet pipe (11). One port of the three-way valve (12) is connected to an air inlet assembly, and the air inlet assembly is connected to a slag discharge pipe (14) provided on one side wall of the furnace body (1) to recover sand particles and waste heat. The other port of the three-way valve (12) is connected to a second air inlet pipe.

5. The energy-saving fluidized bed furnace air inlet control device according to claim 4, characterized in that: The air intake assembly includes a bend (131), an air intake pipe (134), a filter cover (135), and a second filter screen (139). The bend (131) is fixed to a three-way valve (12). A filter cylinder (133) is connected to the lower end of the bend (131). The filter cover (135) is fixed to the inside of the filter cylinder (133) to correspond to the end of the bend (131). The lower end of the filter cylinder (133) has a connection port (136). An air intake pipe (134) with both ends connected to the filter cylinder (133) and the slag discharge pipe (14) is provided. The inner wall of the slag discharge pipe (14) has a second filter screen (139) corresponding to the end of the air intake pipe (134).

6. The energy-saving fluidized bed furnace air inlet control device according to claim 5, characterized in that: The air intake assembly also includes a first filter screen (132), a first feed pipe (137) and a second control valve (138). The first feed pipe (137) is connected to the inside of the connection port (136), and one end of the first feed pipe (137) is connected to the inside of the air box (2). The second control valve (138) is installed on one side of the first feed pipe (137). The first filter screen (132) is fixed to the upper inside of the air box (2) to correspond to one end of the first feed pipe (137).

7. The energy-saving fluidized bed furnace air inlet control device according to claim 6, characterized in that: The height of the edge of the first filter screen (132) is greater than the height of one end of the connecting pipe (6) and the first air outlet pipe (9).

8. The energy-saving fluidized bed furnace air inlet control device according to claim 5, characterized in that: The air inlet assembly also includes a second feeding pipe (140), a third control valve (141), and a second air outlet pipe (142). The second feeding pipe (140) is connected to the inside of the connection port (136), and one end of the second feeding pipe (140) is connected to the inside of the furnace body (1). The third control valve (141) is installed on the second feeding pipe (140). The second air outlet pipe (142) is fixed to the lower end of one side wall of the bend pipe (131), and one end of the second air outlet pipe (142) is connected to the inside of the gas storage tank (3). The second air outlet pipe (142) has a second solenoid valve.

9. A method for controlling the air intake of an energy-saving fluidized bed furnace, employing the control device described in any one of claims 1-8, characterized in that, It also includes the following steps: Step A: The blower (4) blows air into the inside of the air box (2) through the connecting pipe (6). The air enters the inside of the furnace body (1) through the air cap (10) to aid combustion and suspend the fuel. At the same time, a portion of the air enters the inside of the gas storage tank (3) through the air guide pipe (7) for storage. Step B: When fuel is added to the inside of the furnace body (1) through the fuel port, the sensor (5) detects the fuel and then transmits the signal to the first control valve (91). The first control valve (91) adjusts the opening to increase so that air flows into the inside of the air box (2) through the first air outlet pipe (9), thereby increasing the amount of air flowing into the inside of the furnace body (1). After the sensor (5) detects that no fuel has been added for a period of time, the first control valve (91) disconnects the connection between the first air outlet pipe (9) and the air box (2). Step C: When the furnace body (1) discharges slag to the outside through the slag discharge pipe (14), the three-way valve (12) controls the connection between the bend pipe (131) and the first air inlet pipe (11). The filter cylinder (133) generates suction force, and the sand particles inside the slag discharge pipe (14) are sucked into the filter cylinder (133) through the suction pipe (134). The coal gangue falls down along the slag discharge pipe (14) by its own gravity and is discharged. The filter cover (135) isolates the sand particles inside the filter cylinder (133). The heat of the sand is introduced into the inside of the connecting pipe (6) through the bend pipe (131), the first air inlet pipe (11) and the fan (4), and then enters the air box (2). Step D: When the three-way valve (12) controls the second air inlet pipe to connect with the first air inlet pipe (11), the second control valve (138) connects the first feeding pipe (137) with the inside of the air box (2), so that the sand particles flow into the inside of the air box (2) along the inclined first feeding pipe (137) under the action of gravity, and the air flowing into the inside of the air box (2) through the connecting pipe (6) blows, so as to re-enter the inside of the furnace body (1) for replenishment.

10. The method for controlling the air intake of an energy-saving fluidized bed furnace according to claim 9, characterized in that, In step D, the following is replaced: when the three-way valve (12) controls the second air inlet pipe to connect with the first air inlet pipe (11), the third control valve (141) connects the second feeding pipe (140) with the inside of the furnace body (1), and at the same time, the second solenoid valve controls the second air outlet pipe (142) to connect with the inside of the gas storage tank (3). The high-pressure gas inside the gas storage tank (3) is blown into the filter cylinder (133) and the inside of the second feeding pipe (140) through the bend pipe (131) to replenish the sand particles inside the furnace body (1).

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