High-temperature slag waste heat recovery device of CFB boiler burning coal gangue

Abstract

The utility model discloses a high-temperature slag waste heat recovery device of a CFB boiler burning coal gangue, which comprises the CFB boiler, a conveying device and a waste heat recovery device, a boiler slag discharge bin is arranged at the bottom of the CFB boiler, a discharge port is arranged at the lower end of the boiler slag discharge bin, one end of the conveying device is positioned below the discharge port, and the other end of the conveying device is positioned below the waste heat recovery device. And the other end is positioned above the waste heat recovery device. The waste heat recovery device has the beneficial effects that the conveying device conveys boiler slag to the position above the waste heat recovery device from the discharging opening, the boiler slag enters the waste heat recovery device to make contact with the heat exchange pipe, heat is absorbed through water or steam in the heat exchange pipe, waste heat recovery is achieved, and the boiler slag subjected to heat exchange enters the conveying device through the discharging hopper to be subjected to follow-up treatment or transportation. The flow of the high-temperature slag particles realizes the overall uniform flow of the material, and secondary heat exchange media such as air do not need to be introduced, so that the problems of poor stability, heavy pollution, large circulating water consumption and low waste heat recovery grade of the current traditional treatment process are effectively solved.

Description

Technical Field

[0001] This utility model relates to the field of high-temperature slag waste heat recovery in CFB boilers that burn coal gangue, and specifically to a high-temperature slag waste heat recovery device for CFB boilers that burn coal gangue. Background Art

[0002] Coal gangue is one of the largest industrial solid wastes in my country in terms of annual emissions and cumulative stock. During coal production, coal gangue accounts for 15% of total coal emissions, amounting to approximately 450 million tons annually. Power generation and building materials are the main uses of coal gangue. In power generation, the CFB (Continuous Fluid Boiler) process is primarily employed. After combustion, a large amount of high-temperature boiler slag is discharged. This slag contains significant amounts of heat, and its recovery is crucial for energy conservation, emission reduction, and improving the overall thermal efficiency of boilers.

[0003] Existing methods for recovering waste heat from high-temperature slag mainly include the Rasa method, slag pool method, bottom filtration method, and InBa method. These methods mainly granulate the slag by water quenching. However, these methods are prone to explosion during production, cause heavy pollution, require a large amount of circulating water, and result in high moisture content in the granulated slag particles. Most importantly, this part of the waste heat is not utilized.

[0004] Secondly, a slag cooler is used to recover the waste heat of high-temperature slag. The high-temperature circulating water output by the slag cooler can be directly injected into the boiler for preheating or input into the heating network for heating. However, there are the following drawbacks to using a slag cooler for slag waste heat recovery: (1) Slag coolers usually produce hot water and cannot provide high-quality steam, resulting in low waste heat recovery grade and low heat recovery efficiency; (2) Since the main heating surface of the device is a rotating film-type wall cylinder, the water inlet and steam outlet are connected to the cylinder by a rotary joint. The moving end and the stationary end of the rotary joint need to be connected by a sealing surface. The relative movement of the moving and stationary ends will cause the sealing surface to wear, thus affecting its service life; (3) The high-temperature material turns over in the cylinder and collides with and is eroded by the heat exchange surface, which greatly shortens the service life of the heating surface tube; (4) The slag cooler drum needs to be electrically driven, which consumes a lot of electricity. Utility Model Content

[0005] The purpose of this invention is to provide a high-temperature slag waste heat recovery device for a CFB boiler that burns coal gangue, in order to solve the aforementioned technical problems of low efficiency and high energy consumption in high-temperature slag waste heat recovery from coal gangue.

[0006] To solve the above-mentioned technical problems, this utility model provides a high-temperature slag waste heat recovery device for a CFB boiler that burns coal gangue, which includes a CFB boiler, a conveying device and a waste heat recovery device. A boiler slag discharge bin is provided at the bottom of the CFB boiler, and a discharge port is provided at the lower end of the boiler slag discharge bin. One end of the conveying device is located below the discharge port, and the other end is located above the waste heat recovery device.

[0007] Furthermore, the conveying device is located between the CFB boiler and the waste heat recovery device, and the conveying device is placed at an angle, with the lower left end of the conveying device located directly below the discharge port and the upper right end of the conveying device located directly above the waste heat recovery device.

[0008] Furthermore, the waste heat recovery device includes a buffer silo and a heat exchange silo. The buffer silo is located directly above the waste heat recovery device, and the heat exchange silo is located below the buffer silo. A discharge hopper is located below the heat exchange silo, and a conveying device is located below the discharge hopper.

[0009] Furthermore, the heat exchange chamber is equipped with heat exchange tubes, which are arranged in an inclined and / or transverse and / or longitudinal manner. One end of the heat exchange tube is a water inlet, and the other end is a steam outlet. The heat exchange tubes are bare tubes or special-form heat exchange surface tubes with extended heating surfaces.

[0010] Furthermore, the inner wall of the heat exchange chamber is provided with an insulation layer and a fire-resistant layer, the fire-resistant layer is located on the innermost side of the heat exchange chamber, and the insulation layer is located between the fire-resistant layer and the heat exchange layer.

[0011] Furthermore, the furnace wall of the heat exchange chamber adopts a membrane water-cooled wall structure.

[0012] Furthermore, the conveying device adopts a chain bucket conveyor or a slant bridge loading trolley.

[0013] Furthermore, a discharge valve is provided between the boiler slag discharge bin and the discharge port.

[0014] Furthermore, the conveying device is covered with an insulation cover.

[0015] The beneficial effects of this utility model are as follows: Compared with the prior art, the high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue involves the boiler slag at the bottom of the CFB boiler being discharged through the slag discharge hopper and then conveyed by a conveying device to the top of the waste heat recovery device. The boiler slag enters the waste heat recovery device and comes into contact with the heat exchange tubes. Heat is absorbed by the water or steam inside the heat exchange tubes, thus achieving waste heat recovery. The heated steam flows out through the steam outlet at the top of the heat exchange tubes for boiler use. The boiler slag that has undergone heat exchange enters the conveying device through the discharge hopper for further processing or transportation.

[0016] This technology uses non-mechanical moving bed flow to achieve heat exchange. The flow of high-temperature slag particles achieves uniform flow of the material as a whole, eliminating the need to introduce secondary heat exchange media such as air. This effectively solves the problems of poor stability, heavy pollution, large consumption of circulating water, and low grade of waste heat recovery in current traditional treatment processes.

[0017] This device does not require a blower, and the solid particles fall due to gravity. The equipment has low self-power consumption, reduces the operating cost of the entire process, has good economic efficiency, and increases the final net power generation.

[0018] The device has a small footprint, is easy to maintain, and has controllable costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the main structure of a high-temperature slag waste heat recovery device for a CFB boiler that burns coal gangue.

[0020] Figure 2 This is a schematic diagram of the main structure of a second scheme for a high-temperature slag waste heat recovery device for a CFB boiler that burns coal gangue.

[0021] The components are: 1. CFB boiler; 2. Boiler slag discharge bin; 3. Discharge valve; 4. Discharge port; 5. Conveying device; 51. Chain bucket conveyor; 52. Inclined bridge loading trolley; 6. Waste heat recovery device; 61. Buffer bin; 62. Heat exchange bin; 63. Discharge hopper; 7. Water inlet; 8. Steam outlet; 9. Conveying device. DETAILED DESCRIPTION

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only one embodiment of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] To make the objectives, technical solutions and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0024] In the following description, references to "an embodiment," "an embodiment," "an example," "example," etc., indicate that the described embodiment or example may include a particular feature, structure, characteristic, property, element, or limitation, but not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element, or limitation. Furthermore, the repeated use of the phrase "an embodiment according to this application," while possibly referring to the same embodiment, does not necessarily refer to the same embodiment.

[0025] In this embodiment: as Figure 1 As shown, the system includes a CFB boiler 1, a conveying device 5, and a waste heat recovery device 6. A boiler slag discharge bin 2 is installed at the bottom of the CFB boiler 1, and a discharge port 4 is installed at the lower end of the boiler slag discharge bin 2. One end of the conveying device 5 is located below the discharge port 4, and the other end is located above the waste heat recovery device 6. The integrated design improves the overall efficiency and reliability of the system.

[0026] The conveying device 5 is located between the CFB boiler 1 and the waste heat recovery device 6. The conveying device 5 is placed at an angle, with the lower left end of the conveying device 5 directly below the discharge port 4 and the upper right end of the conveying device 5 directly above the waste heat recovery device 6. The precise docking of the conveying device 5 with the discharge port 4 and the waste heat recovery device 6 reduces material leakage and waste.

[0027] The waste heat recovery device 6 includes a buffer silo 61 and a heat exchange chamber 62. The buffer silo 61 is located directly above the waste heat recovery device 6, and the heat exchange chamber 62 is located below the buffer silo 61. A discharge hopper 63 is located below the heat exchange chamber 62, and a conveying device 9 is located below the discharge hopper 63. The buffer silo 61 regulates the material flow rate, prevents the heat exchange chamber 62 from overloading, and improves heat exchange efficiency and system stability. The boiler slag after waste heat recovery is quickly discharged to avoid accumulation. Heat exchange tubes can be arranged in three directions within the heat exchange chamber 62: inclined, transverse, and longitudinal. A water inlet 7 is located at one end of the heat exchange tube, and a steam outlet 8 is located at the other end. The heat exchange tubes are plain tubes or special-form heat exchange surface tubes with extended heating surfaces, such as finned tubes or "Ω" tubes. The inclined design enhances the heat exchange effect. The heat exchange tubes provide efficient heat conduction and structural strength, improving the heating efficiency of the boiler feed water.

[0028] The furnace wall of heat exchange chamber 62 adopts a membrane water-cooled wall structure, which is in direct contact with boiler slag; it can serve as a heating surface to absorb the sensible heat of steel slag, and also as a furnace wall, meeting the requirements for strength and sealing.

[0029] The inner wall of the heat exchange chamber 62 is provided with an insulation layer and a fire-resistant layer. The fire-resistant layer is located on the innermost side of the heat exchange chamber 62, and the insulation layer is located between the fire-resistant layer and the heat exchange layer. The fire-resistant layer protects the equipment from high temperature damage, and the insulation layer reduces heat loss, thereby improving the safety and energy efficiency of the heat exchange chamber 62.

[0030] The conveying device 5 adopts a chain bucket conveyor 51 or a slant bridge loading trolley 52, providing a flexible conveying solution to adapt to different conveying distances and improve the adaptability and efficiency of the system.

[0031] A discharge valve 3 is installed between the boiler slag discharge bin 2 and the discharge port 4. By controlling the discharge valve 3, the discharge speed and amount of slag are adjusted to prevent blockage and ensure the stable operation of the system.

[0032] The conveyor device 5 is covered with an insulation cover, which reduces heat loss, protects the conveyor device 5, extends the service life of the equipment, and improves the energy efficiency of the system.

[0033] Workflow: Boiler slag at the bottom of CFB boiler 1 is discharged through boiler slag discharge bin 2 and discharge port 4. Discharge valve 3 controls the discharge speed and amount. Chain bucket conveyor 51 or inclined bridge loading trolley 52 transports boiler slag from discharge port 4 to the top of waste heat recovery device 6. Boiler slag enters buffer bin 61 for temporary storage to control the flow rate into heat exchange bin 62. Slag enters heat exchange bin 62 from buffer bin 61, contacts heat exchange tubes, absorbs heat through water or steam in the heat exchange tubes to achieve waste heat recovery. Heated steam flows out through steam outlet 8 at the top of heat exchange tubes for boiler use. Boiler slag that has undergone heat exchange enters transportation device 9 through discharge hopper 63 for further processing or transportation.

[0034] The above description of the disclosed embodiments enables those skilled in the art to implement or use this 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, this 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 high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue, characterized in that: It includes a CFB boiler, a conveying device and a waste heat recovery device. The bottom of the CFB boiler is provided with a boiler slag discharge bin, and the lower end of the boiler slag discharge bin is provided with a discharge port. One end of the conveying device is located below the discharge port, and the other end is located above the waste heat recovery device.

2. The high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 1, characterized in that: The conveying device is located between the CFB boiler and the waste heat recovery device. The conveying device is placed at an angle, with the lower left end of the conveying device located directly below the discharge port and the upper right end of the conveying device located directly above the waste heat recovery device.

3. The high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 1, characterized in that: The waste heat recovery device includes a buffer silo and a heat exchange silo. The buffer silo is located directly above the waste heat recovery device, and the heat exchange silo is located below the buffer silo. A discharge hopper is located below the heat exchange silo, and a conveying device is located below the discharge hopper.

4. A high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 3, characterized in that: The heat exchange chamber is equipped with heat exchange tubes, which are arranged in an inclined and / or transverse and / or longitudinal manner. One end of the heat exchange tube is a water inlet, and the other end is a steam outlet. The heat exchange tubes are bare tubes or special-form heat exchange surface tubes with extended heating surfaces.

5. A high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 3, characterized in that: The inner wall of the heat exchange chamber is provided with an insulation layer and a fire-resistant layer. The fire-resistant layer is located on the innermost side of the heat exchange chamber, and the insulation layer is located between the fire-resistant layer and the heat exchange layer.

6. A high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 1, characterized in that: The conveying device is a chain bucket conveyor or a slant bridge loading trolley.

7. A high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 1, characterized in that: A discharge valve is installed between the boiler slag discharge bin and the discharge port.

8. A high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 1, characterized in that: The conveying device is covered with an insulation cover.

9. A high-temperature slag waste heat recovery device for a CFB boiler burning coal gangue according to claim 3, characterized in that: The furnace wall of the heat exchange chamber adopts a membrane water-cooled wall structure.

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