Fluidized bed reaction device for processing fly ash material

Abstract

The utility model provides a kind of processing flowable heat preservation reaction device of returning ash material, including shell, fluidization wind unit being arranged in the bottom of shell;Intermediate partition wall is equipped in shell for being separated into two material chambers with shell, and the top and bottom of intermediate partition wall have gap with shell to make two material chambers communicate;The top of shell is equipped with feed inlet in one of material chambers, and discharge outlet is equipped on the side wall of another material chamber.The utility model is separated into two material chambers by setting intermediate partition wall, and channel is arranged in the lower part of intermediate partition wall, so that powder material coming in feed inlet is gradually entered into another material chamber after accumulating in one side material chamber and presenting fluidized state, until material level reaches the lowest point of discharge outlet, material will overflow equipment, prolongs the residence time of material in equipment, thereby prolongs the reaction time of material, so that material can be completely dehydrated under relatively low temperature, and qualified product is obtained, and system heat consumption is reduced.

Description

Technical Field

[0001] This utility model relates to the field of gaseous suspension roasting technology, and in particular to a reaction device for processing ash-returned materials. Background Technology

[0002] In the alumina production process, the conventional process uses a primary cyclone dust collector and an electrostatic precipitator or bag filter to recover dust from the flue gas. The dust is mainly aluminum hydroxide mixed with some fine alumina powder. The collected dust is transported to the calcining furnace cooling system through the ash return system. In the calcining furnace cooling system, the heat brought in by the alumina heats the ash return material, causing the ash return material to undergo a de-crystallization reaction to generate alumina.

[0003] The dehydration reaction of aluminum hydroxide can occur at temperatures above 200°C, with varying dehydration rates at different temperatures. Within a certain range, higher temperatures result in faster dehydration, shortening the reaction time. However, to meet the high temperatures required for the aluminum hydroxide dehydration reaction, the calcining furnace needs to provide more heat to the cooling system, leading to increased exhaust gas temperature and higher system heat consumption. Within a certain range, lowering the reaction temperature significantly reduces the dehydration rate, necessitating ensuring sufficient reaction time at that temperature for complete dehydration to obtain a qualified product.

[0004] In the current alumina production process, the heat exchange between powder materials and air or flue gas is completed almost instantaneously upon contact. To increase the reaction time, it is impossible to rely on the equipment in the original system. Therefore, there is an urgent need for a heat preservation device to process materials in the ash return system and extend the reaction time. Summary of the Invention

[0005] To address the aforementioned technical problems, this utility model proposes a fluidized bed heat-insulating reaction device for processing returned ash materials, which solves the problem that the reaction time is difficult to guarantee in the existing returned ash system at relatively low reaction temperatures.

[0006] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0007] A fluidized bed reactor for processing returned ash materials includes a shell and a fluidizing air unit located at the bottom of the shell. A partition wall inside the shell divides it into two chambers, with gaps at the top and bottom of the partition wall to allow communication between the two chambers. An inlet is located at the top of one chamber, and an outlet is located on the side wall of the other chamber. This invention uses a partition wall to divide the shell into two chambers, with a channel at the bottom of the partition wall. This allows powdered material entering through the inlet to accumulate and fluidize on one side before gradually flowing into the other chamber. When the material level reaches the lowest point of the outlet, it overflows the equipment, thus extending the reaction time.

[0008] Furthermore, the housing includes an upper tank and a lower tank disposed at the bottom of the upper tank; the intermediate partition wall, the inlet and the outlet are disposed in the upper tank.

[0009] Furthermore, the lower tank is provided with a slag discharge port, which is connected to the material chamber.

[0010] Furthermore, the fluidizing air unit includes a high-temperature resistant perforated plate disposed at the bottom of the lower tank and an air cap disposed on the high-temperature resistant perforated plate.

[0011] Furthermore, the lower end of the wind cap is welded and fixed to the high-temperature resistant perforated plate, and the inlet of the wind cap is aligned with the hole on the high-temperature resistant perforated plate.

[0012] Furthermore, the fluidizing air unit also includes a fluidizing air inlet disposed on the lower tank, the fluidizing air inlet being connected to the inlet of the air cap.

[0013] Furthermore, the lower trough is a funnel-shaped structure that is larger at the top and smaller at the bottom, and there are two lower troughs, which are respectively located at the bottom of the two material chambers.

[0014] Furthermore, in order to facilitate the discharge of the small amount of material entering the lower tank, a slag discharge port is provided at the lower end of the lower tank.

[0015] Furthermore, the upper tank and the high-temperature resistant perforated plate are provided with a high-temperature resistant lining.

[0016] Furthermore, in order to eliminate fluidizing air, an exhaust port is provided at the top of the upper tank.

[0017] The beneficial effects of this utility model are:

[0018] 1. This utility model connects the feed inlet to the discharge pipe outlet of the primary cyclone cooler, the discharge outlet to the air inlet of the secondary cyclone cooler, the exhaust outlet to the air inlet of the secondary cyclone cooler, and the fluidizing air inlet to the air supply fan, providing fluidizing air for the equipment and providing an air source for the fluidized flow of powder materials.

[0019] 2. By setting up an intermediate partition wall and a channel at the bottom of the intermediate partition wall, the powder material entering from the feed inlet accumulates on one side and enters the fluidized state before gradually entering the other side. When the material level reaches the lowest point of the discharge port, the material will overflow the equipment, thereby extending the reaction time of the material.

[0020] 3. This utility model can realize the dehydration reaction of aluminum hydroxide and aluminum oxide in the returned ash material outside the aluminum hydroxide gas suspension roasting furnace, ensuring the reaction time and allowing the aluminum hydroxide to decompose fully, while not requiring too high a reaction temperature, thereby saving the heat consumption of the roasting furnace system. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of this utility model.

[0023] In the diagram: 1. Lower tank, 2. High-temperature resistant perforated plate, 3. Upper tank, 4. Feed inlet, 5. Intermediate partition wall, 6. Exhaust outlet, 7. Discharge outlet, 8. Lower tank slag discharge outlet, 9. Material chamber slag discharge outlet, 10. Steel structure support, 11. Fluidized air inlet, 12. Air cap. Detailed Implementation

[0024] 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 some embodiments 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.

[0025] like Figure 1As shown in Embodiment 1 of this utility model, a fluidized bed heat-insulating reaction device for processing ash-returning materials includes a shell and a fluidizing air unit disposed at the bottom of the shell. In this embodiment, the shell includes an upper tank 3 and a lower tank 1 disposed at the bottom of the upper tank 3. The fluidizing air unit is disposed at the bottom of the upper tank 3 and on the lower tank 1 to provide fluidizing air to the upper tank 3. The ash-returning materials in the upper tank 3 undergo a dehydration reaction under the action of the fluidizing air. The upper tank 3 of the shell is provided with a middle partition wall 5 to divide the upper tank 3 into two material chambers, and there are gaps between the top and bottom of the middle partition wall 5 and the top and bottom of the upper tank 3 to allow communication between the top and bottom of the two material chambers, and the gaps between the top and bottom of the middle partition wall 5 form a channel. An inlet 4 is provided at the top of one of the material chambers on the upper tank 3, and an outlet 7 is provided on the side wall of the other material chamber. Figure 1 As shown, in this embodiment, the upper tank 3 has a feed inlet 4 at the top of the right-side material chamber and a discharge outlet 7 on the side wall of the upper tank 3 in the left-side material chamber. Additionally, the left-side material chamber has an exhaust outlet 6 at its top. The feed inlet 4 connects to the outlet of the primary cyclone cooler's discharge pipe, allowing the returned ash material to enter the right-side material chamber of the fluidized bed heat-insulating reaction device through the discharge pipe. The discharge outlet 7 connects to the inlet of the secondary cyclone cooler for discharging the dehydrated material. The exhaust outlet 6 connects to the air inlet of the secondary cyclone cooler for exhaust. The exhaust outlet 6 and the discharge outlet 7 are located at different positions on the air inlet of the secondary cyclone cooler. During the process, the powdery material, i.e., the returned ash material (a mixture of alumina and aluminum hydroxide), gradually accumulates in the right-side material chamber and becomes fluidized. Given the height difference between the left and right sides, the fluidized material, under gravity, gradually enters the left-side material chamber through the channel at the bottom of the intermediate partition wall 5. As the feed rate increases, the material levels in both chambers simultaneously increase, generally maintaining a slightly higher level in the right-side chamber than in the left. When the material level in the left-side chamber exceeds the lowest point of the discharge port, the material overflows the equipment and enters the inlet of the next-stage cyclone cooler. The arrangement of the two material chambers increases the residence time of the material within the equipment, thereby extending the dehydration reaction time.

[0026] Example 2 differs from Example 1 in that, as Figure 1 As shown, the fluidizing air unit includes a high-temperature resistant perforated plate 2 disposed at the bottom of the lower tank 1 and an air cap 12 disposed on the high-temperature resistant perforated plate 2. The inlet of the air cap 12 is aligned with the hole on the high-temperature resistant perforated plate 2, and then the lower end of the air cap 12 is welded and fixed to the high-temperature resistant perforated plate 2. The gap between the lower end of the intermediate partition wall 5 and the high-temperature resistant perforated plate 2 with a movable distance forms a lower channel.

[0027] Furthermore, the fluidizing air unit also includes a fluidizing air inlet 11 disposed on the lower tank 1. The fluidizing air inlet is connected to a blower to provide fluidizing air to the equipment and to provide an air source for the fluidized flow of powder materials. The air introduced through the fluidizing air inlet 11 enters the lower tank 1 and then enters the material chamber of the upper tank through the inlet of the air cap 12, forming fluidizing air that acts on the powder materials.

[0028] Example 3 differs from Example 2 in that, as Figure 1 As shown, the lower trough 1 is a funnel-shaped structure, wider at the top and narrower at the bottom, and there are two lower troughs 1, each located at the bottom of one of the two material chambers. The larger ends of both funnel-shaped lower troughs 1 are fixedly connected to the high-temperature resistant perforated plate 2. The smaller ends of the lower troughs 1 face downwards. Furthermore, a slag discharge port 8 is provided at the smaller end (lower end) of the lower trough 1 to facilitate slag discharge.

[0029] Example 4 differs from Example 1 in that, as Figure 1 As shown, the lower tank 1 is provided with a material chamber slag discharge port 9, the upper end of which is connected to the material chamber for cleaning the material after reaction in the upper tank.

[0030] Example 5 differs from Example 2 in that, as Figure 1 As shown, both the inner side of the upper tank 3 and the upper side of the high-temperature resistant perforated plate 2 are provided with high-temperature resistant linings. These high-temperature resistant linings can adopt a combined lining structure, consisting of an insulation layer and a refractory layer. The insulation layer is composed of aerogel and nano-insulation boards, while the refractory layer uses high-temperature resistant, low-creep, high-alumina brick DRL-140 or high-temperature resistant castable DCL-65. The upper tank 3 and lower tank 1 are constructed with steel plates and stiffening plates, using ordinary carbon steel Q235B; the high-temperature resistant perforated plate 2 is made of 06Cr25Ni20 stainless steel.

[0031] Example 6: The working process of the fluidized bed heat preservation reactor for processing returned ash materials includes:

[0032] (1) Before the equipment is in normal operation, the fluidizing blower provides fluidizing air and introduces it into the lower tank 1, so that the lower tank 1, the high temperature resistant perforated plate 2, and the upper tank 3 are all in the fluidizing air protection state, and the device is in a slightly positive pressure environment to prevent the material entering the upper tank 3 from entering the lower tank 1 through the air cap 12 and the high temperature resistant perforated plate 2.

[0033] (2) During operation, the powder material (a mixture of alumina and aluminum hydroxide) coming in from the feed inlet gradually accumulates in the right material chamber and presents a fluidized state. When there is a height difference between the materials on the left and right sides, the fluidized material gradually enters the left material chamber through the lower channel at the bottom of the middle partition wall 5 under the action of gravity. As the feed rate increases, the material level height of the left and right material chambers increases at the same time, basically keeping the material level of the right material chamber slightly higher than that of the left material chamber. When the material level of the left material chamber is higher than the lowest point of the discharge port, the material will overflow the equipment and enter the inlet of the next stage cyclone cooler through the discharge pipe.

[0034] (3) The material temperature at the feed inlet is basically the same as the temperature at the discharge outlet of the previous cyclone separator, and the material temperature is 600~750℃;

[0035] (4) Fluidizing air passes through the blower equipment. In order to ensure the material layer height of the fluidized bed heat preservation reactor equipment, the fluidizing air pressure is ≥19.6kPaG, which increases with the increase of the material layer height, and the fluidizing air temperature is 50~80℃;

[0036] (5) Due to the addition of fluidizing air and imported materials, the temperature inside the fluidized bed heat preservation reactor is basically maintained between 550 and 700°C, and the temperature at the exhaust outlet is 30 to 50°C lower than the temperature of the material inside the equipment.

[0037] (6) By adjusting the fluidizing air flow rate and pressure, the material insulation reaction time in the fluidized bed reactor can be adjusted, and the reaction time can be controlled at 10~20 minutes;

[0038] (7) The upward velocity of the fluidizing air in the fluidized bed insulated reactor is controlled at 0.5~1.5m / s;

[0039] (8) The main reaction in the fluidized bed reactor is the removal of water of crystallization by aluminum hydroxide, which produces aluminum oxide;

[0040] (9) The material temperature at the outlet of the fluidized bed insulated reactor is 500~650℃.

[0041] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some or all of the technical features therein, within the spirit and principles of the present utility model, shall not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present utility model, and shall all be included within the protection scope of the present utility model.

Claims

1. A fluidized bed heat-insulating reaction device for processing returned ash materials, characterized in that, It includes a housing and a fluidizing air unit located at the bottom of the housing; a middle partition wall (5) is provided inside the housing to divide the housing into two material chambers, and there are gaps between the top and bottom of the middle partition wall (5) and the housing so that the two material chambers can communicate; an inlet (4) is provided on the top of one of the material chambers and an outlet (7) is provided on the side wall of the other material chamber.

2. Fluidized thermal reaction apparatus for processing fly ash material according to claim 1, characterized in that, The housing includes an upper tank (3) and a lower tank (1) located at the bottom of the upper tank (3); the intermediate partition wall (5), the feed inlet (4) and the discharge outlet (7) are located in the upper tank (3).

3. Fluidized bed thermal reactor for the treatment of fly ash material according to claim 2, characterized in that, The lower tank (1) is provided with a material chamber slag discharge port (9), which is connected to the material chamber.

4. Fluidized bed thermal reaction apparatus for processing fly ash material according to claim 2 or 3, characterized in that, The fluidizing air unit includes a high-temperature resistant perforated plate (2) disposed at the bottom of the lower tank (1) and an air cap (12) disposed on the high-temperature resistant perforated plate (2).

5. Fluidized bed heat recovery reactor for the treatment of fly ash material according to claim 4, characterized in that, The lower end of the hood (12) is welded and fixed to the high-temperature resistant perforated plate (2), and the inlet of the hood (12) is aligned with the hole on the high-temperature resistant perforated plate (2).

6. The fluidized bed reaction apparatus for processing ash-return material according to claim 4, wherein The fluidizing air unit also includes a fluidizing air inlet (11) disposed on the lower tank (1), and the fluidizing air inlet (11) is connected to the inlet of the air cap (12).

7. Fluidized bed thermal reaction apparatus for processing fly ash material according to claim 2 or 3 or 5 or 6, characterized in that, The lower trough (1) is a funnel-shaped structure with a larger top and a smaller bottom, and there are two lower troughs (1), which are respectively located at the bottom of the two material chambers.

8. The fluidized bed heat-insulating reaction apparatus for processing returned ash materials according to claim 7, characterized in that, The lower end of the lower tank body (1) is provided with a slag discharge port (8).

9. Fluidized bed thermal reaction apparatus for processing fly ash material according to claim 2 or 3 or 5 or 6 or 8, characterized in that, The upper tank (3) and the high-temperature resistant perforated plate (2) are provided with high-temperature resistant linings.

10. Fluidized bed thermal reaction apparatus for processing ash-return material according to claim 2 or 3 or 5 or 6 or 8, characterized in that The top of the upper tank (3) is provided with an exhaust port (6).

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