A high-temperature solid bulk material moving bed enhanced heat exchange system

Abstract

The present invention discloses a moving bed enhanced heat exchange system for high-temperature solid bulk materials. The system includes a granulator for granulating high-temperature slag. The granulator is positioned below the moving bed, which is equipped with multiple heating surfaces and an air distribution device at its base. This system ensures sufficient cooling of the high-temperature particles, prevents heat buildup and allows for the timely removal of accumulated bulk particles. This system ensures safe and stable operation of the dry granulation system while enhancing waste heat recovery.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste heat recovery of high-temperature liquid slag, and in particular relates to a high-temperature solid bulk material moving bed enhanced heat exchange system. Background Art

[0002] Currently, the most common method for treating high-temperature blast furnace slag is water quenching and granulation. After water quenching and granulation, high-temperature blast furnace slag is used as a raw material in cement production. While this method enables large-scale utilization of blast furnace slag, the process consumes significant amounts of water resources. It is estimated that processing one ton of high-temperature slag requires approximately one ton of new water and approximately 10 tons of recycled water. Furthermore, the water quenching process releases significant amounts of H₂S and SO₂ gases, which corrode buildings, damage equipment, and degrade the working environment. It also generates significant amounts of water vapor, resulting in a significant waste of the high sensible heat contained in the blast furnace slag.

[0003] Dry treatment technology utilizes indirect or direct contact between high-temperature blast furnace slag and a heat transfer medium to granulate the slag and recover sensible heat. This process consumes no precious water resources and releases virtually no harmful gases such as H2S and SO2. With my country's full commitment to energy conservation and emission reduction efforts in the steel industry, dry centrifugal granulation technology for high-temperature blast furnace slag has garnered significant attention within the industry. During the dry centrifugal granulation process, the high-temperature, high-viscosity slag is flung off the surface of a high-speed rotating granulator, forming droplets in the air. These tiny droplets undergo intense direct heat exchange with the heat transfer medium in the air, typically air. This lowers the droplet temperature and causes a phase change on the droplet surface, forming a solidified layer. As the temperature drops further, the droplets gradually transform into small solid particles. Since the rotation speed of the turntable during the granulation process is extremely fast, generally up to 1000-2000r / min, the tangential velocity of the droplets is extremely fast, which makes the heat exchange of the droplets in the circumferential space of the granulator limited. At this time, only a thin solidification layer can form on the surface of the droplets, and the inner layer is still in liquid phase. The overall temperature of the particles can still be as high as 800-900°C. In order to further reduce the temperature of the particles, it is necessary to strengthen the heat exchange of the particles in the moving bed. At this time, the cooling time of the high-temperature particles (high-temperature solid bulk materials) in the moving bed has become a key control factor in the blast furnace slag waste heat recovery technology. Due to insufficient cooling, the existing waste heat recovery moving bed device causes the slag particles to return to heat and stick together in the heat exchange field, resulting in sedimentation and accumulation, which affects the waste heat recovery rate and cannot achieve the ideal slag discharge effect.

[0004] In summary, a new moving bed high-temperature solid bulk material enhanced heat exchange system is urgently needed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and provide a high-temperature solid bulk material moving bed enhanced heat exchange system, which is used to solve the technical problem that in the current dry centrifugal granulation process of liquid molten slag, due to insufficient cooling, the slag particles are heated and adhered in the heat exchange field, resulting in sedimentation and accumulation, which affects the slag particle recovery effect.

[0006] The present invention adopts the following technical solutions:

[0007] A high-temperature solid bulk moving bed enhanced heat exchange system includes a granulator for granulating high-temperature slag. The granulator is arranged above the moving bed, multiple heating surfaces are arranged in the moving bed, and an air distribution device is arranged at the bottom of the moving bed.

[0008] Specifically, the particle settling section of the moving bed is provided with a suspended screen-type heating surface.

[0009] Furthermore, a dust cleaning device is provided on the top of the suspended screen-type heating surface.

[0010] Specifically, the suspension section of the moving bed is provided with heat exchange tubes.

[0011] Furthermore, the heat exchange tube is in the form of an extended heating surface.

[0012] Furthermore, a material level accumulation area is provided below the heat exchange tube.

[0013] Furthermore, the accumulation area is provided with a buried pipe heating surface.

[0014] Specifically, the cooling gas introduced by the air distribution device is air or nitrogen.

[0015] Specifically, the inner wall of the high-temperature solid bulk material moving bed enhanced heat exchange system is provided with a cooling wall surface.

[0016] Furthermore, the cooling wall surface adopts a coil cooling wall, a film cooling wall or a non-film cooling wall.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] A high-temperature solid bulk material moving bed enhanced heat exchange system, wherein a granulator is arranged above the moving bed, which prolongs the falling distance of the granulated high-temperature particles and improves the heat exchange between the particles and each heated surface. During the falling process, the particles sequentially exchange heat with the heating surface of the free settling section and the heating surface of the suspension section. An air distribution device is provided at the bottom of the moving bed to blow in cooling medium to enhance the convective heat exchange between the particles and the heated surface, thereby further preventing the particles from thermally resisting and sticking together.

[0019] Furthermore, a suspended screen-type heating surface is provided in the free settling section of the particles to enhance the radiation heat exchange during the particle descent process; the use of a suspended screen-type heating surface in the form of an extended heating surface can increase the collision between the particles and the heating surface during the descent process, thereby enhancing solid-solid heat exchange.

[0020] Furthermore, the dust cleaning device can effectively solve the problem of slag particles being heated and bonded in the heat exchange field, causing sedimentation and accumulation, thus ensuring smooth discharge.

[0021] Furthermore, the particle drop suspension section is equipped with multiple layers of horizontal heat exchange tube bundles to increase the particle residence time in the heat exchange area and further recover the particle waste heat.

[0022] Furthermore, heat exchange tubes can be designed with extended heating surfaces to extend the residence time and contact area between the particles and the tube bundle, enhancing solid-solid heat transfer. Furthermore, after passing through the free settling and suspension sections, the particles fall to the bulk accumulation area at the bottom of the moving bed. Depending on the actual bulk material temperature, an embedded heating surface can be installed in this accumulation area to enhance solid-solid heat transfer and further recover the low-temperature waste heat of the particles.

[0023] Furthermore, an air distribution device is set at the bottom of the moving bed, and the cooling gas flows through the moving bed from bottom to top, which strengthens the gas-solid heat exchange and prevents the particles from bonding. The cooling gas can be selected from but not limited to air and nitrogen.

[0024] Furthermore, a cooling wall is installed on the wall of the moving bed to maintain the temperature of the moving bed wall and enhance the radiation heat transfer of the particles in the moving bed during their descent. The cooling wall surface can be selected based on the actual application and is not limited to coil cooling wall, membrane cooling wall, or non-membrane cooling wall.

[0025] In summary, the present invention allows high-temperature particles to be fully cooled, prevents back-heat adhesion, and promptly cleans accumulated bulk particles, thereby ensuring safe and stable operation of the dry granulation system and enhancing waste heat recovery.

[0026] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the system of the present invention.

[0028] Among them: 1. Granulator; 2. Suspended screen heating surface; 3. Cooling wall; 4. Heat exchange tube; 5. Accumulation area; 6. Air distribution device; 7. Dust removal device. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center," "longitudinal," "lateral," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "one side," "one end," and "one side" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, in the description of the present invention, unless otherwise specified, "a plurality" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0032] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0033] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0034] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0035] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0036] The present invention provides a high-temperature solid bulk material moving bed enhanced heat exchange system, which adopts a multi-stage heating surface and bottom cooling air to ensure sufficient cooling of the particles. At the same time, through the dust cleaning system arranged on the top of the suspended screen-type heating surface, it can effectively solve the problem of slag particles returning to heat and sticking to each other in the heat exchange field, causing sedimentation and accumulation, and ensure smooth discharge.

[0037] See also Figure 1 The present invention provides a high-temperature solid bulk material moving bed enhanced heat exchange system, including a body, a granulator 1, a suspended screen type heating surface 2, a heat exchange tube 4, a buried tube heating surface and an air distribution device 6.

[0038] A granulator 1 and a moving bed are sequentially arranged in the main body from top to bottom. The granulator 1 is arranged at the top of the particle settling section of the moving bed and is used to granulate the high-temperature slag; the suspended screen-type heating surface 2 is arranged in the particle settling section of the moving bed, and the heat exchange tube 4 is arranged in the suspension section below the particle settling section. An accumulation area 5 is provided below the heat exchange tube 4, and an air distribution device 6 is located at the bottom of the moving bed. The multi-section heating surface and the air distribution device 6 at the bottom ensure that the particles are fully cooled.

[0039] The inner wall of the body is provided with a cooling wall surface 3, and the cooling wall surface 3 adopts a coil cooling wall, a film cooling wall or a non-film cooling wall.

[0040] Preferably, the heat exchange tube 4 can be selected with an extended heating surface according to actual conditions, including but not limited to nail head tubes and H-shaped fin tubes, to enhance solid-solid heat exchange by increasing the heating surface and particle residence time.

[0041] Preferably, the high-temperature solid bulk material moving bed enhanced heat exchange system of the present invention can provide an embedded pipe heating surface in the accumulation area 5 according to actual conditions.

[0042] Preferably, a dust cleaning device 7 is installed on the top of a single screen of the suspended screen-type heating surface 2 or on the top between adjacent screens to clean the accumulated particles between the heating surfaces in forms including but not limited to vibration dust blowing, sonic dust blowing, air dust blowing, etc.

[0043] The cooling gas introduced by the air distribution device 6 is air, nitrogen, etc.

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0045] After centrifugal granulation, the high-temperature slag falls into the moving bed in the state of semi-molten particles, and freely settles through the arranged suspended screen heating surface 2 and heat exchange tubes 4, thereby enhancing radiation heat exchange.

[0046] Among them, the suspended screen-type heating surface 2 and the heat exchange tube 4 can be selected in the form of finned tubes to increase the contact and collision area with the particles and enhance the solid-solid heat exchange between the particles and the heating surface.

[0047] When particles accumulate and clog the suspended screen type heating surface 2 or the extended heating surface during the free settling stage, they are cleaned by the dust cleaning device 7 provided on the top of the suspended screen type heating surface 2 to ensure stable operation of the system.

[0048] The cooling medium sprayed out by the air distribution device 6 arranged at the bottom of the moving bed passes through the bottom particle accumulation area 5, the heat exchange tube 4, and the suspended screen-type heating surface 2 in sequence, during which the convection heat exchange between the particles and the heating surface is enhanced, and the particles are further prevented from being accumulated and blocked due to reverse heat adhesion.

[0049] In summary, the high-temperature solid bulk material moving bed enhanced heat exchange system of the present invention can achieve sufficient cooling of high-temperature particles, prevent back-heat adhesion, and promptly clean up accumulated bulk particles, thereby enhancing the waste heat recovery effect.

[0050] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A high-temperature solid bulk material moving bed enhanced heat exchange system, characterized in that: The invention comprises a granulator (1) for granulating high-temperature slag, wherein the granulator (1) is arranged above a moving bed, a plurality of heating surfaces are arranged in the moving bed, an air distribution device (6) is arranged at the bottom of the moving bed, a suspended screen-type heating surface (2) is arranged in a particle settling section of the moving bed, a heat exchange tube (4) is arranged in a suspended section of the moving bed, a material level accumulation area (5) is arranged below the heat exchange tube (4), the accumulation area (5) is provided with a buried pipe heating surface, and a cooling wall surface (3) is arranged on the inner wall of the high-temperature solid bulk material moving bed enhanced heat exchange system.

2. The high-temperature solid bulk moving bed enhanced heat exchange system according to claim 1, characterized in that: A dust cleaning device (7) is provided on the top of the suspended screen-type heating surface (2).

3. The high-temperature solid bulk material moving bed enhanced heat exchange system according to claim 1, characterized in that: The heat exchange tube (4) is in the form of an extended heating surface.

4. The high-temperature solid bulk moving bed enhanced heat exchange system according to claim 1, characterized in that: The cooling gas introduced by the air distribution device (6) is air or nitrogen.

5. The high-temperature solid bulk moving bed enhanced heat exchange system according to claim 1, characterized in that: The cooling wall surface (3) adopts a coil cooling wall, a film cooling wall or a non-film cooling wall.

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