Fluidized bed boiler for burning biomass

Abstract

The utility model discloses a fluidized bed boiler of burning biomass belongs to fluidized bed boiler field, including boiler main part, separator and heat exchange device, the inside bottom of boiler main part is equipped with combustion chamber, and the inside of boiler main part is equipped with water cooled wall and heated plate, and the upper end of boiler main part is equipped with steam pocket. Through setting up, install first hopper and second hopper on the conveying pipe, cooperate control valve and use, can adopt same group conveying pipe and conveying screw rod to complete respectively to the conveying of biomass and limestone, reduced the space occupation, reduced the use cost simultaneously, set up the baffle in the conveying pipe close to the one end of drive motor, open the air outlet on the baffle, cooperate the use of breather pipe and air pump, can carry out the air blowing in the process of conveying material, utilize the gas to blow the material, prevent the material from adhering on the inner wall of conveying pipe, can ensure the conveying effect, avoid the situation of jam.

Description

Technical Field

[0001] This utility model relates to the field of fluidized bed boilers, and in particular to a fluidized bed boiler that burns biomass. Background Technology

[0002] Fluidized bed boilers are high-efficiency, low-pollution boilers that utilize fluidized bed combustion technology. Their core principle is to fluidize fuel particles through high-speed airflow, creating a fluid-like combustion state. This results in advantages such as strong fuel adaptability, high combustion efficiency, and low pollutant emissions. Biomass-fired fluidized bed boilers utilize biomass as fuel, effectively reducing harmful exhaust gases produced in the combustion chamber while conserving resources.

[0003] Existing fluidized bed boilers that burn biomass use conveying devices to transport biomass and limestone into the boiler for fluidized combustion. However, conveying biomass and limestone requires two separate conveying devices, resulting in a large space occupation and increased operating costs. Furthermore, during the conveying process, the conveying devices cannot be ventilated, causing materials to easily adhere to the inner walls of the conveying devices, thus affecting the conveying efficiency and throughput. Utility Model Content

[0004] The main objective of this invention is to provide a fluidized bed boiler that burns biomass, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A fluidized bed boiler for burning biomass includes a boiler body, a separator, and a heat exchange device. The boiler body has a combustion chamber at its bottom and water-cooled walls and heating plates inside. The boiler body has a steam drum at its top. The heat exchange device is divided into a superheater and an economizer along the flue gas flow direction. The superheater has a steam discharge pipe, and the economizer has a cold water injection pipe. The boiler body is connected to a feeding structure. The separator is connected to the boiler body through a flue gas duct, and the lower end of the separator has a return pipe.

[0006] Preferably, the feeding structure includes a conveying pipe, a first hopper, a second hopper, control valves, a discharge pipe, a conveying screw, and a drive motor. The conveying pipe is installed and connected to the boiler body. The first hopper and the second hopper are installed on the conveying pipe. The two control valves are respectively located at the lower ends of the first hopper and the second hopper. The discharge pipe is installed at the end of the conveying pipe and is connected to the boiler body. The conveying screw is rotatably disposed inside the conveying pipe. The drive motor is fixed at the end of the conveying pipe, and the output shaft of the drive motor is connected to the conveying screw.

[0007] Preferably, the feeding structure further includes a pressure sensor, a partition, an air outlet, an air chamber, a vent pipe, and an air pump. The pressure sensor is installed on the conveying pipe, the partition is fixed inside the conveying pipe, the air outlet is opened on the partition, the air chamber is disposed between the conveying pipe and the partition, the vent pipe is connected to the conveying pipe and communicates with the air chamber, and the air pump is connected to the vent pipe.

[0008] Preferably, the return pipe at the lower end of the separator is connected to the lower end of the boiler body, and the upper end of the separator is provided with a pipe connected to the heat exchange device.

[0009] Preferably, the ends of the steam discharge pipe and the cold water injection pipe are both connected to the steam drum, and the steam drum is connected to the water-cooled wall and the heating plate.

[0010] Preferably, an air preheater is provided at the lower end of the heat exchange device, and a first air duct and a second air duct are respectively connected to the two air preheaters. One end of the first air duct is connected to the bottom of the boiler body, and the other end is provided with a first fan. One end of the second air duct is connected to the middle of the boiler body, and the other end is provided with a second fan.

[0011] Compared with the prior art, this utility model has the following beneficial effects: This biomass-burning fluidized bed boiler, through the set feeding structure, installs the first and second hoppers on the conveying pipe. With the help of the control valve, the same set of conveying pipes and conveying screws can be used to convey biomass and limestone separately, reducing the space occupied and the operating cost. A baffle is set at the end of the conveying pipe near the drive motor, and an air vent is opened on the baffle. With the help of the air pipe and air pump, air can be blown during the material conveying process. The air blows the material to prevent the material from adhering to the inner wall of the conveying pipe, which can ensure the conveying effect and avoid blockage. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the feeding structure of this utility model; Figure 3 This utility model Figure 2 Enlarged view of point A in the middle.

[0013] In the diagram: 1. Boiler body; 2. Combustion chamber; 3. Water-cooled wall; 4. Heating plate; 5. Steam drum; 6. Feeding structure; 601. Conveying pipe; 602. First hopper; 603. Second hopper; 604. Control valve; 605. Discharge pipe; 606. Conveying screw; 607. Drive motor; 608. Pressure sensor; 609. Baffle plate; 610. Air outlet; 611. Air chamber; 612. Vent pipe; 613. Air pump; 7. Separator; 8. Return pipe; 9. Heat exchanger; 10. Steam discharge pipe; 11. Cold water injection pipe; 12. Air preheater; 13. First air duct; 14. Second air duct; 15. First fan; 16. Second fan. Detailed Implementation

[0014] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0015] like Figures 1-3 As shown, a fluidized bed boiler that burns biomass includes a boiler body 1, a separator 7, and a heat exchange device 9. The bottom of the boiler body 1 is provided with a combustion chamber 2, and the boiler body 1 is provided with a water-cooled wall 3 and a heating plate 4. The upper end of the boiler body 1 is provided with a steam drum 5. The heat exchange device 9 is divided into a superheater and an economizer along the flue gas flow direction. The superheater is provided with a steam discharge pipe 10, and the economizer is provided with a cold water injection pipe 11. A feeding structure 6 is connected to the boiler body 1. The separator 7 is connected to the boiler body 1 through a flue gas pipe, and the lower end of the separator 7 is provided with a return pipe 8.

[0016] The return pipe 8 at the lower end of the separator 7 is connected to the lower end of the boiler body 1, and the upper end of the separator 7 is provided with a pipe connected to the heat exchange device 9. The ends of the steam discharge pipe 10 and the cold water injection pipe 11 are both connected to the steam drum 5, and the steam drum 5 is connected to the water-cooled wall 3 and the heating plate 4. An air preheater 12 is provided at the lower end of the interior of the heat exchange device 9. A first air duct 13 and a second air duct 14 are respectively connected to the two air preheaters 12. One end of the first air duct 13 is connected to the bottom of the boiler body 1, and the other end is provided with a first fan 15. One end of the second air duct 14 is connected to the middle of the boiler body 1, and the other end is provided with a second fan 16.

[0017] When using a fluidized bed boiler that burns biomass, the feed structure 6 is used to transport biomass and limestone to the combustion chamber 2 inside the boiler body 1. The first blower 15 is started and blows air from the bottom of the boiler body 1 through the first air duct 13. The blown air acts on the biomass and limestone to form a fluidized bed, and combustion takes place inside the combustion chamber 2. Meanwhile, the air generated by the second blower 16 is blown into the middle of the boiler body 1 through the second air duct 14, which can supplement oxygen and enhance combustion, thereby improving the combustion effect.

[0018] The flue gas generated by combustion flows upward through the flue gas duct into the separator 7. During this process, the water-cooled wall 3 and the heating plate 4 are subjected to thermal radiation and transfer heat to the steam drum 5. The water in the steam drum 5 is heated to form high-temperature steam and is discharged through the steam exhaust pipe 10. The flue gas entering the separator 7 is separated. The unburned solid residue falls into the boiler body 1 through the return pipe 8 to continue combustion, while the gas is transported through the pipeline to the heat exchange device 9 and flows downward. When the flue gas flows to the superheater area, it further heats the steam in the steam exhaust pipe 10 in that area to form superheated steam for discharge. When the flue gas flows to the economizer area, it preheats the cold water in the cold water injection pipe 11 in that area. The preheated water is injected into the steam drum 5 and can quickly absorb heat and evaporate, which can improve the boiler efficiency. When the flue gas continues to move to the air preheater 12, it can preheat the gas flowing in the first air duct 13 and the second air duct 14, which can both heat the combustion air and further reduce the temperature of the discharged flue gas.

[0019] According to the above implementation scheme, the feeding structure 6 includes a conveying pipe 601, a first hopper 602, a second hopper 603, a control valve 604, a discharge pipe 605, a conveying screw 606, and a drive motor 607. The conveying pipe 601 is installed and connected to the boiler body 1. The first hopper 602 and the second hopper 603 are installed on the conveying pipe 601. Two control valves 604 are respectively set at the lower ends of the first hopper 602 and the second hopper 603. The discharge pipe 605 is installed at the end of the conveying pipe 601 and is connected to the boiler body 1. The conveying screw 606 is rotatably installed inside the conveying pipe 601. The drive motor 607 is fixed at the end of the conveying pipe 601, and the output shaft of the drive motor 607 is connected to the conveying screw 606.

[0020] The feeding structure 6 also includes a pressure sensor 608, a partition 609, an air outlet 610, an air chamber 611, a vent pipe 612, and an air pump 613. The pressure sensor 608 is installed on the conveying pipe 601, the partition 609 is fixed inside the conveying pipe 601, the air outlet 610 is opened on the partition 609, the air chamber 611 is located between the conveying pipe 601 and the partition 609, the vent pipe 612 is connected to the conveying pipe 601 and communicates with the air chamber 611, and the air pump 613 is connected to the vent pipe 612.

[0021] When using the feeding structure 6, the first hopper 602 and the second hopper 603 are filled with biomass and limestone, respectively. After starting the drive motor 607, the conveying screw 606 rotates inside the conveying pipe 601. After opening the corresponding control valve 604, the material in the hopper falls into the conveying pipe 601 and is moved by the conveying screw 606, and finally conveyed into the boiler body 1. By opening and closing the control valve 604, different materials in the two hoppers can be conveyed separately. Simultaneously, during material conveying, the air pump 613 is activated. After the gas is compressed, it is delivered to the air chamber 611 through the air pipe 612, and finally blown into the conveying screw 606 on the conveying pipe 601 through the air outlet 610 on the partition 609. The high-pressure gas blown out cleans the inside of the conveying pipe 601, ensuring complete material conveying and avoiding blockage. At the same time, during use, the pressure sensor 608 monitors the air pressure inside the conveying pipe 601 in real time and feeds back the air pressure data. Based on the feedback data, the air pump 613 adjusts the air pressure to ensure operational stability.

[0022] It should be noted that by setting the feeding structure 6, the first hopper 602 and the second hopper 603 are installed on the conveying pipe 601 and used in conjunction with the control valve 604. The same set of conveying pipes 601 and conveying screws 606 can be used to convey biomass and limestone respectively, which reduces the space occupied and the operating cost. A baffle 609 is set at the end of the conveying pipe 601 near the drive motor 607. An air outlet 610 is opened on the baffle 609. It is used in conjunction with the air pipe 612 and the air pump 613 to blow air during the material conveying process. The air blows the material to prevent the material from adhering to the inner wall of the conveying pipe 601, which can ensure the conveying effect and avoid blockage.

[0023] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A fluidized bed boiler for burning biomass, comprising a boiler body (1), a separator (7), and a heat exchange device (9), wherein the boiler body (1) has a combustion chamber (2) at its bottom, and a water-cooled wall (3) and a heating plate (4) are provided inside the boiler body (1), and a steam drum (5) is provided at the top of the boiler body (1). The heat exchange device (9) is divided into a superheater and an economizer along the flue gas flow direction, wherein a steam discharge pipe (10) is provided at the superheater, and a cold water injection pipe (11) is provided at the economizer, characterized in that: The boiler body (1) is connected to a feeding structure (6), the separator (7) is connected to the boiler body (1) through a flue gas pipe, and the lower end of the separator (7) is provided with a return pipe (8).

2. A fluidized bed boiler for burning biomass according to claim 1, characterized in that: The feeding structure (6) includes a conveying pipe (601), a first hopper (602), a second hopper (603), a control valve (604), a discharge pipe (605), a conveying screw (606), and a drive motor (607). The conveying pipe (601) is installed on the boiler body (1). The first hopper (602) and the second hopper (603) are installed on the conveying pipe (601). The two control valves (604) are respectively located at the lower ends of the first hopper (602) and the second hopper (603). The discharge pipe (605) is installed at the end of the conveying pipe (601) and is connected to the boiler body (1). The conveying screw (606) is rotatably installed inside the conveying pipe (601). The drive motor (607) is fixed at the end of the conveying pipe (601) and the output shaft of the drive motor (607) is connected to the conveying screw (606).

3. A fluidized bed boiler for burning biomass according to claim 2, characterized in that: The feeding structure (6) also includes a pressure sensor (608), a partition (609), an air outlet (610), an air chamber (611), a ventilation pipe (612), and an air pump (613). The pressure sensor (608) is installed on the conveying pipe (601). The partition (609) is fixed inside the conveying pipe (601). The air outlet (610) is opened on the partition (609). The air chamber (611) is located between the conveying pipe (601) and the partition (609). The ventilation pipe (612) is connected to the conveying pipe (601) and communicates with the air chamber (611). The air pump (613) is connected to the ventilation pipe (612).

4. A fluidized bed boiler for burning biomass according to claim 3, characterized in that: The return pipe (8) at the lower end of the separator (7) is connected to the lower end of the boiler body (1), and the upper end of the separator (7) is provided with a pipe connected to the heat exchange device (9).

5. A fluidized bed boiler for burning biomass according to claim 4, characterized in that: The ends of the steam discharge pipe (10) and the cold water injection pipe (11) are both connected to the steam drum (5), and the steam drum (5) is connected to the water-cooled wall (3) and the heating plate (4).

6. A fluidized bed boiler for burning biomass according to claim 5, characterized in that: The lower end of the heat exchange device (9) is provided with an air preheater (12). The two air preheaters (12) are respectively connected to a first air duct (13) and a second air duct (14). One end of the first air duct (13) is connected to the bottom of the boiler body (1), and the other end is provided with a first fan (15). One end of the second air duct (14) is connected to the middle of the boiler body (1), and the other end is provided with a second fan (16).

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