A combined ash removal device for waste heat boilers in steelmaking converters

Abstract

This utility model discloses a combined ash removal device for a steelmaking converter waste heat boiler. The device is used in a converter flue gas waste heat boiler system, which includes multiple evaporators connected in series and an economizer located after the last evaporator. Connecting sections are provided between adjacent evaporators and between evaporators and the economizer. Each evaporator is connected to a steam drum. A mechanical vibrator is installed on the outer side of the lower header of the heat exchange tube bundle in the evaporator. A mechanical vibrator is also installed on the outer side of the connecting rod below the economizer heat exchange tube bundle in the economizer. Sonic ash removers are installed on the connecting sections and at the flue gas inlet and outlet. The structural design of the heat exchange tube bundle in this application ensures that the tube bundle has suitable elasticity, allowing it to transmit vibration waves and vibrate after being vibrated, thus achieving the purpose of removing stubborn and sticky ash. Simultaneously, the synergistic effect of the sonic ash remover achieves thorough ash removal.

Description

Technical Field

[0001] This utility model belongs to the technical field of ash removal devices, and in particular relates to a combined ash removal device for a waste heat boiler in steelmaking converters. Background Technology

[0002] Currently, the main methods used for dust removal and purification of converter steelmaking flue gas and gas recovery are the OG method, the LT method, and the semi-dry method. However, regardless of the method, all of them suffer from the problem that dust emissions cannot meet industry requirements, which seriously restricts the improvement of energy conservation and consumption reduction in the steelmaking converter process.

[0003] The converter flue gas is mainly composed of CO (CO: 60%–86%), containing some CO2, N2, and small amounts of O2 and trace impurities, while also carrying high concentrations of dust (dust content: 80–150 g / Nm³). 3 The dust mainly consists of iron oxides (FeO, Fe2O3), iron powder, and CaO, SiO2, MnO, MgO, etc. The converter flue gas has a high dust concentration, reaching 80–150 g / Nm³. 3 The dust contains fine particles (approximately 5-30 μm) that are highly sticky and difficult to remove. Since the main component of converter dust is metal oxide (containing approximately 60% iron), its density is greater than that of dust under other operating conditions.

[0004] In recent years, in order to improve the "negative energy" steelmaking level of converters and increase the steam output per ton of steel, some steel plants have been trying to recover the waste heat from the medium temperature of converter flue gas. However, the actual effect is far from the expected effect. The reason is that although relevant ash removal measures have been taken (such as conventional sonic ash removers), converter dust easily forms a highly adhesive ash layer on the heat exchange surface of the waste heat boiler, especially in the convection tube bundle area of ​​the waste heat boiler, which is more serious and sometimes even blocks the flue gas passage, causing the equipment to malfunction.

[0005] There are currently various dust removal technologies for heat exchange equipment with high dust content, but each has the following problems:

[0006] Shutdown cleaning: Requires shutdown and manual entry into confined spaces, which is time-consuming, poses high safety risks, and is detrimental to continuous production. Pulse purge: The shock wave attenuates quickly, potentially clearing only localized ash accumulation. However, dead zones exist within dense tube bundles, making effective removal of highly viscous ash, caking ash, or slag layers difficult. Acoustic resonance cleaning: Conventional acoustic cleaners typically generate sound energy intensities between 140 and 155 decibels, which is ineffective for highly viscous, heavily scaled, or caking ash. Their effective range is limited, and they generate significant noise during operation. Steam cleaning: The purging range is limited, leaving ash accumulation in unreached areas. The increased humidity of the cleaning steam and ash further exacerbates ash caking.

[0007] Therefore, there is an urgent need to provide a reliable ash removal device for waste heat boilers in steelmaking converters to solve the problem of incomplete dust removal in heat exchange equipment for high-dust flue gas. Utility Model Content

[0008] The purpose of this utility model is to address the problem of incomplete dust removal in heat exchange equipment for high-dust-content flue gas, and to propose a combined ash removal device for waste heat boilers in steelmaking converters.

[0009] This application provides a combined ash removal device for a steelmaking converter waste heat boiler. The ash removal device is used in a converter flue gas waste heat boiler system, which includes multiple evaporators connected in series and an economizer installed after the last evaporator.

[0010] Connection sections are provided between adjacent evaporators, as well as between evaporators and economizers; each evaporator is connected to the steam drum.

[0011] A mechanical vibrator is installed on the outer side of the end position of the lower header of the heat exchange tube bundle in the evaporator;

[0012] A mechanical vibrator is provided on the outer side of the connecting rod end below the economizer heat exchange tube bundle in the economizer;

[0013] Sonic soot removers are installed on the connecting section and the flue gas inlet and outlet.

[0014] Furthermore, the evaporator includes a heat exchange tube bundle and an ash hopper disposed below the heat exchange tube bundle; the heat exchange tube bundle includes multiple heat exchange tube plates; the heat exchange tube bundle is vertically suspended.

[0015] The evaporator is equipped with an outer shell;

[0016] Each heat exchanger tube bundle consists of an upper header, heat exchanger tubes, and a lower header from top to bottom. The upper header of each heat exchanger tube bundle is suspended and fixed, while the lower header is a free end.

[0017] A mechanical vibrator is installed on the outer side of the end of the lower junction box.

[0018] Furthermore, the economizer includes an economizer heat exchange tube bundle and an economizer ash hopper disposed below the economizer heat exchange tube bundle.

[0019] The economizer heat exchanger tube bundle includes multiple serpentine heat exchanger tube segments. The upper bend of each heat exchanger tube segment is suspended and fixed, and the economizer heat exchanger tube bundle expands freely downward. The lower part of the economizer heat exchanger tube bundle is connected to adjacent economizer heat exchanger tube bundles through clamps and connecting rods.

[0020] A mechanical vibrator is provided on the outside of the end of the connecting rod.

[0021] Furthermore, the mechanical rapper includes a rapping driver, a rapping rod, a guide rod, and a seal connected in sequence;

[0022] The end of the guide rod is fitted with a conductive pad on the impact surface. The conductive pad is a non-metallic product.

[0023] Furthermore, the conductive pad material is selected as toughened nylon PA66.

[0024] Furthermore, the flare of the acoustic soot remover faces the heat exchange surface of the equipment.

[0025] Furthermore, the gas used in the acoustic soot cleaner is nitrogen.

[0026] Compared with the prior art, the significant progress of this application is that: the heat exchange tube bundle of the boiler evaporator and economizer adopts a vertical tube suspension structure, which is adapted to the ash characteristics of converter flue gas and the requirements for ash removal, and ash is not easy to accumulate on the heat exchange tubes; the heat exchange tube bundle adopts an upper suspension system, which facilitates the transmission of vibration waves in the tube bundle system to achieve the ash removal effect.

[0027] A combined mechanical rapping and acoustic cleaning method is employed to address the problem of stubborn ash accumulation on the heat exchange surfaces of converter flue gas boilers. The two technologies work synergistically, complementing each other to effectively remove both loose and stubborn ash from the heat exchange surfaces. Specifically, the mechanical rapping device uses mechanical impact energy to act on the heat exchange tube bundle, causing the ash to peel off and fall due to vibration fatigue or be carried away by the flue gas. This method is suitable for cleaning converter flue gas with strong adhesion and high density. The mechanical rapping device also has excellent practical application results in removing slag from the high-temperature section of the boiler's heat exchange tubes. Considering the characteristics of converter flue gas dust, a high-power, high-intensity acoustic cleaner is selected, operating at a relatively high frequency to remove loose loose ash deposited during boiler operation. By combining the strengths of both cleaning devices and adjusting the control program in a timely manner according to the actual boiler operation, a comprehensive cleaning effect for the waste heat boiler is achieved. Attached Figure Description

[0028] Figure 1 A schematic diagram of the converter flue gas waste heat boiler provided by this utility model;

[0029] Figure 2 A schematic diagram of the evaporator provided by this utility model;

[0030] Figure 3 A schematic diagram of the evaporator provided by this utility model from the perspective of the windward side;

[0031] Figure 4 A schematic diagram of the economizer provided for this utility model;

[0032] Figure 5 A schematic diagram of the economizer provided by this utility model from the perspective of the windward side;

[0033] Figure 6 A schematic diagram of the mechanical vibration dust removal device for the evaporator provided by this utility model;

[0034] Figure 7 A schematic diagram of the economizer mechanical vibration ash removal device provided by this utility model;

[0035] Figure 8 A partial schematic diagram of the installation of the acoustic dust collector provided by this utility model;

[0036] The meanings of the reference numerals in the attached diagrams are as follows: 1. Vaporization flue; 2. Flue gas inlet; 3. Evaporator: 31. Shell; 311. Heat exchanger tube bundle support block; 312. Wall panel; 313. Ash hopper; 32. Heat exchanger tube bundle; 321. Upper header; 322. Heat exchanger tube; 323. Lower header; 324. Header connecting block; 325. Downward lead-out bend. 4. Connecting section; 5. Economizer: 51. Shell; 511. Tube bundle hanger; 512. Wall panel; 513. Economizer ash hopper; 52. Economizer heat exchanger tube bundle; 521. Upper elbow; 522. Heat exchanger tube; 523. Clamping plate; 524. Connecting rod. 6. Sonic soot remover; 7. Flue gas outlet; 8. Mechanical vibrator; 81. Vibrator driver; 82. Vibrator rod; 83. Guide rod; 84. Seal; 85. Conductive pad; 9. Riser; 10. Downsink; 11. Steam drum. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0038] This application relates to dust removal and cleaning of heat exchanger tubes in dusty flue gas heat exchange devices, including but not limited to: converter flue gas, electric furnace flue gas, and rotary hearth furnace flue gas in the iron and steel metallurgical industry; calcium carbide furnace flue gas; coal-fired and power generation boiler flue gas in the power and energy industry; coal gasification flue gas; and cement and glass production kiln flue gas in the building materials industry. This utility model is particularly suitable for cleaning heat exchanger tube bundles in boiler heat exchangers with high dust content and stubborn ash accumulation.

[0039] When implementing waste heat recovery from converter flue gas at medium temperature, a vaporization flue duct 1 is installed to introduce the high-temperature flue gas before the LT, OG, or semi-dry flue gas cooling equipment into the waste heat boiler system. At this time, the flue gas temperature before the vaporization flue duct 1 is approximately 800–900℃, and the flue gas temperature before the convection section of the waste heat boiler is approximately 600–700℃.

[0040] like Figure 1As shown, the ash removal device provided in this application is specifically used in a converter flue gas waste heat boiler system. The convection section of the converter flue gas waste heat boiler includes multiple evaporators 3 connected in series and an economizer 5 located after the last evaporator 3. A connecting section 4 is provided between adjacent evaporators 3 and between evaporators 3 and economizer 5. The evaporators 3 are respectively connected to the steam drum 11.

[0041] After being cooled by heat exchange in the multi-stage evaporator 3 and economizer 5 of the waste heat boiler convection section, the converter flue gas is discharged through the flue gas outlet 7 and enters the dust removal system. In one feasible embodiment, the multi-stage evaporator 3 has 5 stages, each connected to the steam drum 11, forming a boiler steam-water circulation system. The water used for heat exchange in the evaporator 3 absorbs heat from the flue gas, forming a steam-water mixture inside the tubes. Through steam-water circulation, the generated saturated steam is separated and output through the steam drum. The economizer 5 absorbs heat from the low-temperature flue gas to heat the boiler feedwater before sending it to the steam drum, thereby realizing the waste heat recovery of the converter flue gas.

[0042] The specific structure of evaporator 3 is shown in [link to evaporator 3]. Figures 2 to 3 .

[0043] Evaporator 3 includes heat exchange tube bundle 32 and ash hopper 313 disposed below heat exchange tube bundle 32; heat exchange tube bundle 32 includes multiple heat exchange tube plates; heat exchange tube bundle 32 is suspended and fixed.

[0044] The outer shell 31 is provided for the evaporator 3;

[0045] Each heat exchanger tube bundle consists of an upper header 321, a heat exchanger tube 322, and a lower header 323 from top to bottom. The upper header 321 of each heat exchanger tube bundle 32 is suspended and fixed, while the lower header 323 is a free end. Expansion displacement is absorbed by the descending bend 325. This structural design of the heat exchanger tube bundle is particularly suitable for mechanical rapping cleaning methods.

[0046] like Figure 3 As shown, a mechanical vibrator 8 is installed on the outer side of the lower header 323 of the heat exchange tube bundle 32 in the evaporator 3. The vibrating force generated by the mechanical vibrator 8 is transmitted to the lower header 323 through the conductive pad 85 and the guide rod 83. Since the heat exchange tube bundle 32 is a structure in which the upper header 321 is suspended and fixed, when the lower header 323 is vibrated, the vibration wave is quickly transmitted to the entire tube bundle. The dust adhering to the surface of the heat exchange tubes is removed from the surface under the action of vibration and carried away by the flue gas flow, or it settles into the ash hopper 313 and is discharged under the action of gravity. For the high-temperature section of the boiler evaporator, when there is molten ash from the converter cooling and solidifying on the surface of the heat exchange tubes, the slag can be peeled off by vibrating the tube bundle 32, thus achieving the effect of removing accumulated ash.

[0047] A single rapping device can act on multiple heat exchanger tubes via the manifold connecting block 324. In this embodiment, a single rapping device corresponds to the rapping and cleaning of 3 heat exchanger tubes.

[0048] For details on the specific structure of economizer 5, please refer to [link / reference]. Figure 4 , Figure 5 .

[0049] The economizer 5 includes an economizer heat exchange tube bundle 52 and an economizer ash hopper 513 located below the economizer heat exchange tube bundle 52. The economizer heat exchange tube bundle 52 includes multiple serpentine heat exchange tube segments, with the upper bend of each segment suspended and fixed, allowing the economizer heat exchange tube bundle 52 to expand freely downwards. Adjacent economizer heat exchange tube bundles 52 are connected below the economizer heat exchange tube bundle 52 via clamps 523 and connecting rods 524. A mechanical vibrator 8 is provided on the outer side of the end of the connecting rod 524. Isolation of the converter flue gas from the outside is achieved by a sealing element 84.

[0050] The rapping force generated by the mechanical rapper 8 is transmitted to the connecting rod 524 through the conductive pad 85 and the guide rod 83. The rapping of the connecting rod 524 causes the serpentine heat exchange tubes to vibrate, thus causing the dust to peel off.

[0051] Since the economizer heat exchange tube bundle 52 is a type of upper suspended structure, when the lower part of the tube bundle is vibrated, the vibration wave is quickly transmitted to the entire tube bundle. The dust adhering to the surface of the heat exchange tube is removed from the surface under the action of vibration and carried away with the flue gas flow, or it falls into the economizer ash hopper 513 for discharge under the action of gravity.

[0052] The specific structure of the mechanical vibrator 8 involved in evaporator 3 and economizer 5 is as follows: Figure 6 , Figure 7 As shown.

[0053] The mechanical vibrator 8 includes a vibrator driver 81, a vibrator rod 82, a guide rod 83, and a seal 84 connected in sequence. When the mechanical vibrator is working, the vibrating force is transmitted to the heat exchange tube bundle through the guide rod, and the heat exchange tube bundle vibrates to achieve the purpose of dust removal.

[0054] The ash discharged from ash hopper 313 and economizer ash hopper 513 is sent to a designated location through the ash conveying system.

[0055] The end of the guide rod 83 is fitted with a conductive pad 85 on the impact surface. The conductive pad 85 is a non-metallic product with high strength and high toughness. Optionally, the conductive pad 85 is made of toughened nylon PA66.

[0056] Seal 84 is used to isolate the converter flue gas from the outside environment.

[0057] The main characteristic of dust accumulation in converter flue gas on boiler heat exchange surfaces is fine powder ash. This dust is characterized by small particle size, high density, and strong adhesion. The boiler structure and matching combined ash removal device adopted in this invention can effectively solve the problem of dust accumulation in converter flue gas. Mechanical vibration has a good removal effect on the deposition of dense and strongly adhesive dust; therefore, mechanical vibration is an effective measure for removing dust from converter flue gas.

[0058] The boiler heat exchange tubes are arranged vertically to reduce the degree of dust accumulation. This invention is particularly suitable for boilers with horizontal flue gas flow. The mechanical vibration cleaning method described in this application utilizes a vibration device to generate periodic impact force. This force is transferred to the ash-accumulated surface of the heat exchange tubes via a mechanical structure. Due to the difference in inertia between the dust particles and the heat exchange tubes, the dust particles adhering to the surface are detached under vibration and carried away by the flue gas flow, or settle into the ash hopper under gravity and discharged. For evaporators 3 or economizers 5, there is a problem of molten converter ash solidifying on the surface of the heat exchange tubes. The mechanical vibration cleaning method removes the solidified slag, effectively cleaning the ash accumulation on the heat exchange tube surface.

[0059] The specific structure of the acoustic soot remover 6 is as follows: Figure 8 As shown.

[0060] In this embodiment of the application, an acoustic soot remover 6 is installed on the flue gas inlet 2 of the boiler heat exchange equipment, the connecting section 4 between each heat exchange equipment, and the flue gas outlet 7. The acoustic waves act on the ash accumulated in the heat exchange tube bundle, causing it to loosen and fall off, and be carried away with the flue gas flow, or settle into the ash hopper and be discharged under the action of gravity.

[0061] When installing the acoustic soot remover, the interface should face the heat exchange surface of the equipment to achieve the best soot removal effect.

[0062] Given the characteristics of converter flue gas dust, this embodiment selects a high-power, high-intensity acoustic soot remover to achieve a better soot removal effect.

[0063] In this embodiment, nitrogen is used as the gas in the acoustic soot cleaner 6.

[0064] This application describes an acoustic soot remover that utilizes acoustic energy to remove ash from industrial equipment. It converts gas into high-power acoustic waves. When the ash on the heated surface is repeatedly pulled and compressed by alternating waves of varying density at a certain frequency, it loosens and falls off, carried away by the flue gas flow, or settles into the ash hopper and is discharged under gravity. The acoustic soot remover features a simple structure, small size, easy installation, no mechanical structure, long service life, high acoustic efficiency, wide frequency range, and significant ash removal effect.

[0065] This invention employs a combined mechanical vibration and acoustic cleaning method, utilizing the synergistic effect of the two cleaning devices to effectively remove dust accumulation on the heat exchanger tube bundle. The operating mode, frequency, and continuous working time of the cleaning device are adjusted according to the actual operating conditions of the boiler system, including changes in flue gas resistance and temperature.

[0066] Specifically, dust and ash deposited on the surface of heat exchange tubes are removed using a high-intensity acoustic ash remover. For stubborn, adherent dust deposits, and even slag on the high-temperature heat exchange surface, mechanical rapping is used to peel off the ash. The structural design of the heat exchange tube bundles in the evaporator and economizer ensures that the tube bundles have appropriate elasticity, allowing them to transmit vibration waves and vibrate after being rapped, thus removing stubborn and sticky ash. The structural design of the heat exchange tube bundles is particularly suitable for mechanical rapping cleaning. Simultaneously, the synergistic effect of the acoustic ash remover achieves thorough ash removal.

[0067] The purpose of this application is to solve the problem of stubborn dust deposition on the boiler heat exchange surface in converter flue gas, thereby improving the efficiency of waste heat boiler, increasing steam production per ton of steel, reducing the resistance drop of flue gas system and the power consumption of fans; the ash removal device scheme of this application is feasible and has good implementation effect.

[0068] Although embodiments of the present 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 present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A combined ash removal device for a waste heat boiler in steelmaking converters, characterized in that, The ash removal device is used in the converter flue gas waste heat boiler system, which includes multiple evaporators (3) connected in series and an economizer (5) installed after the last evaporator (3). A connecting section (4) is provided between adjacent evaporators (3) and between evaporators (3) and economizer (5); A mechanical vibrator (8) is provided on the outside of the end position of the lower header (323) of the heat exchange tube bundle (32) in the evaporator (3); A mechanical vibrator (8) is provided on the outer side of the end of the connecting rod (524) below the economizer heat exchange tube bundle (52) in the economizer (5); An acoustic soot remover (6) is installed on the connecting section (4), the flue gas inlet (2), and the flue gas outlet (7).

2. The soot cleaning device of claim 1, wherein The evaporator (3) includes a heat exchange tube bundle (32) and an ash hopper (313) disposed below the heat exchange tube bundle (32); the heat exchange tube bundle (32) includes multiple heat exchange tube plates; the heat exchange tube bundle (32) is vertically suspended; The outer layer of the evaporator (3) is provided with a shell (31); Each heat exchange tube bundle (32) consists of an upper header (321), a heat exchange tube (322), and a lower header (323) from top to bottom. The upper header (321) of each heat exchange tube bundle (32) is suspended and fixed, while the lower header (323) is a free end. A mechanical vibrator (8) is provided on the outer side of the end position of the lower header (323).

3. The ash cleaning device of claim 1, wherein The economizer (5) includes an economizer heat exchange tube bundle (52) and an economizer ash hopper (513) located below the economizer heat exchange tube bundle (52); The economizer heat exchange tube bundle (52) includes multiple serpentine heat exchange tubes, with the upper bend of each heat exchange tube being suspended and fixed. The economizer heat exchange tube bundle (52) expands freely downwards. The lower part of the economizer heat exchange tube bundle (52) is connected to adjacent economizer heat exchange tube bundles (52) by clamps (523) and connecting rods (524). A mechanical vibrator (8) is provided on the outside of the end of the connecting rod (524).

4. The ash cleaning device of claim 2, wherein The mechanical vibrator (8) includes a vibrator driver (81), a vibrator rod (82), a guide rod (83), and a seal (84) connected in sequence; The end of the guide rod (83) is covered with a conductive pad (85) on the impact surface. The conductive pad (85) is a non-metallic product.

5. The ash cleaning device of claim 4, wherein The conductive pad (85) is made of toughened nylon PA66.

6. The ash cleaning device of claim 1, wherein The flare of the acoustic soot remover (6) faces the heat exchange surface of the equipment.

7. The device according to claim 1, wherein The gas used in the acoustic soot cleaner (6) is nitrogen.

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