Flue gas treatment system

Abstract

The utility model provides a flue gas treatment system, which relates to the technical field of aluminum oxide production, and comprises a flue gas pipeline used for conveying flue gas with a first specified temperature; the heat exchange water pipe is used for conveying industrial water or raw water; the flue gas pipeline and the heat exchange water pipe realize heat exchange through the first heat exchange equipment, so that the industrial water or raw water in the heat exchange water pipe is heated to a second specified temperature; the second heat exchange equipment is used for heating the filtrate in the filtrate tank; the filtrate tank is provided with a filtrate inlet and a filtrate outlet; the filtrate inlet is sequentially connected with red mud filter pressing equipment for producing aluminum oxide, red mud washing equipment and low-temperature dissolution equipment. The flue gas pipeline and the heat exchange water pipe are subjected to heat exchange in the first heat exchange equipment so as to heat industrial water or raw water in the heat exchange water pipe, and filtrate in the filtrate tank and the heat exchange water pipe realize heat exchange through the second heat exchange equipment, so that the filtrate in the filtrate tank is firstly heated and then sent back to the low-temperature dissolution equipment so as to realize alkali recovery.

Description

Technical Field

[0001] This utility model relates to the field of alumina production technology, and in particular to a flue gas treatment system. Background Technology

[0002] See Figure 1 The production of alumina includes processes such as grinding of raw ore slurry, low-temperature leaching, red mud separation, and roasting. The roasting process generates flue gas at 600-900℃. The red mud obtained after separation undergoes processes such as red mud washing and red mud filtration. In the red mud filtration process, the filtrate can be heated to 80-90℃ and then returned to the low-temperature leaching process, serving a purpose of alkali recovery.

[0003] If the flue gas generated during the roasting process is directly filtered through a bag filter, the waste heat of the flue gas will be wasted, which is inconsistent with the company's concept of energy conservation and emission reduction.

[0004] This application aims to fully utilize the waste heat of the flue gas generated during the roasting process, etc., and to use the waste heat of the flue gas to heat the above-mentioned filtrate, which is in line with the company's concept of energy conservation and emission reduction. Utility Model Content

[0005] In response to the above situation, this utility model provides a flue gas treatment system, which aims to solve the technical problem that the waste heat of existing flue gas is wasted, which is inconsistent with the company's concept of energy conservation and emission reduction.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] This utility model provides a flue gas treatment system, including:

[0008] Flue gas duct, used to transport flue gas with a first specified temperature;

[0009] Replace hot water pipes for transporting industrial water or raw water;

[0010] The first heat exchange device is used to exchange heat between the flue gas duct and the hot water exchange pipe, so as to heat the industrial water or raw water in the hot water exchange pipe to the second specified temperature.

[0011] The second heat exchanger is used to heat the filtrate in the filtrate tank to 80~90℃;

[0012] The filtrate tank has a filtrate inlet and a filtrate outlet; the filtrate inlet is sequentially connected to a red mud filter press, a red mud washing device, and a low-temperature leaching device for alumina production; the filtrate outlet is connected to the inlet of the low-temperature leaching device through a filtration device.

[0013] In some embodiments of this utility model, the first heat exchange device includes a vertical finned tube heat exchanger.

[0014] In some embodiments of this utility model, the second heat exchange device includes a heat exchange jacket, which is sleeved outside the filtrate tank.

[0015] In some embodiments of this invention, the flue gas duct is connected to a calcining device for producing alumina.

[0016] In some embodiments of this utility model, the filtration device includes:

[0017] The filter box has an inlet and an outlet, with the outlet located above the inlet;

[0018] The baffle is detachably attached to the inner wall of the filter box;

[0019] Multiple baffles are arranged longitudinally and alternately between the inlet and outlet to form an upwardly meandering flow channel.

[0020] In some embodiments of this utility model, the upper side of the baffle is inclined.

[0021] In some embodiments of this utility model, the ratio of the vertical distance from the liquid inlet to the bottom of the filter box to the height of the filter box is 1 / 6 to 1 / 5.

[0022] In some embodiments of this invention, the inlet and liquid inlet of the flow channel are located on opposite sides of the filter box.

[0023] The embodiments of this utility model have at least the following advantages or beneficial effects:

[0024] 1. The filtrate first enters the filtrate tank through the filtrate inlet for storage, and then returns to the low-temperature leaching equipment through the filtrate outlet to achieve alkali recovery. Heat exchange occurs between the flue gas duct and the hot water exchange pipe in the first heat exchange device to heat the industrial water or raw water in the hot water exchange pipe. The filtrate in the filtrate tank and the industrial water or raw water in the hot water exchange pipe exchange heat through a second heat exchange device to heat the filtrate in the filtrate tank to 80-90°C before sending it back to the low-temperature leaching equipment.

[0025] Second, the filtration equipment can filter out particulate matter mixed in the filtrate to prevent these particulate matter from adhering to the corresponding conveying pipes and causing blockage.

[0026] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The alumina production process flow diagram provided in this application;

[0029] Figure 2 A schematic diagram of the flue gas treatment system provided in this application;

[0030] Figure 3 This is a schematic diagram of the filtration device provided in Example 2;

[0031] Figure 4 This is a schematic diagram of the filtration device provided in Example 3;

[0032] Figure 5 This is a schematic diagram of the filtration device provided in Example 4.

[0033] Icons: 1-Flue gas duct, 2-Hot water exchange pipe, 3-First heat exchange equipment, 4-Second heat exchange equipment, 5-Filtration tank, 51-Filtration inlet, 52-Filtration outlet, 6-Red mud filter press, 7-Red mud washing equipment, 8-Low temperature leaching equipment, 9-Filtration equipment, 91-Filter box, 92-Baffle, 93-Flow channel, 94-Liquid inlet, 95-Liquid outlet. Detailed Implementation

[0034] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the present invention.

[0035] In the description of the embodiments of this utility model, it should be understood that the terms "upper", "lower", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0038] The embodiments of this utility model will be described in detail below.

[0039] Example 1

[0040] See Figures 1-2 This embodiment provides a flue gas treatment system, including a flue gas duct 1, a hot water exchange pipe 2, a first heat exchange device 3, a second heat exchange device 4, and a filter tank 5.

[0041] Flue gas duct 1 is used to transport flue gas having a first specified temperature. The flue gas may include, for example, flue gas at 600-900°C generated by calcining equipment used for alumina production. High-temperature flue gas from other sources may also be used.

[0042] Hot water pipe 2 is used to transport industrial water or raw water.

[0043] The first heat exchange device 3 includes a vertical finned tube heat exchanger; the flue gas duct 1 and the hot water exchange pipe 2 exchange heat through the first heat exchange device 3 to heat the industrial water or raw water in the hot water exchange pipe 2 to a second specified temperature. After passing through the first heat exchange device 3, the flue gas duct 1 is filtered by a bag filter and then discharged to other treatment equipment.

[0044] The second heat exchange device 4 includes a heat exchange jacket, which is fitted outside the filtrate tank 5; the second heat exchange device 4 is used to heat the filtrate in the filtrate tank 5 to 80~90℃.

[0045] The filtrate tank 5 has a filtrate inlet 51 and a filtrate outlet 52; the filtrate inlet 51 is sequentially connected to a red mud filter press 6, a red mud washing device 7, and a low-temperature leaching device 8 for producing alumina; the filtrate outlet 52 is connected to the inlet of the low-temperature leaching device 8 through a filter device 9.

[0046] Red mud is generated in the low-temperature leaching device 8. Specifically, during the alumina production process, bauxite undergoes low-temperature leaching to form a mixed slurry of red mud and sodium aluminate. The red mud mainly consists of solid residues formed during the leaching process of non-alumina minerals in bauxite. After being discharged from the bottom of the low-temperature leaching device 8, the red mud is washed and filtered to obtain filtrate. The filtrate first enters the filtrate tank 5 from the filtrate inlet 51 for storage, and then returns to the low-temperature leaching device 8 from the filtrate outlet 52 to achieve alkali recovery. The flue gas pipe 1 and the hot water exchange pipe 2 exchange heat in the first heat exchange device 3 to heat the industrial water or raw water in the hot water exchange pipe 2. The filtrate in the filtrate tank 5 and the industrial water or raw water in the hot water exchange pipe 2 exchange heat through the second heat exchange device 4 to heat the filtrate in the filtrate tank 5 to 80~90℃ before sending it back to the low-temperature leaching device 8. The filtration device 9 can filter out particulate matter mixed in the filtrate to prevent these particulate matter from adhering to the corresponding conveying pipes and causing blockage.

[0047] Example 2

[0048] See Figures 1-3 The filtration device 9 includes a filter box 91 and baffles 92. The filter box 91 has an inlet 94 and an outlet 95, with the outlet located above the inlet. The baffles 92 are detachably connected to the inner wall of the filter box 91 by means of snap-fit, threaded connection, or other methods; multiple baffles 92 are arranged longitudinally and staggered between the inlet and outlet to form an upwardly meandering flow channel 92.

[0049] The filtrate flows upward along the flow channel 92, while the particulate matter settles under the influence of gravity and the obstruction of the baffle 92, achieving solid-liquid separation and thus preventing the particulate matter in the filtrate from entering the subsequent pipeline and causing pipeline blockage.

[0050] The baffle 92 is detachably connected to the inner wall of the filter box 91, which facilitates the disassembly, assembly, and cleaning of the baffle 92.

[0051] In this embodiment, the liquid inlet is located near the bottom of the filter box 91, and the liquid outlet is located at the top of the filter box 91.

[0052] Example 3

[0053] This embodiment is a further improvement based on embodiment 2.

[0054] See Figures 1-4 The upper side of the baffle 92 is inclined so that the particles settling on the upper side of the baffle 92 can roll down to the bottom of the filter box 91, avoiding the size of the flow channel 92 and the flow rate of the liquid outlet due to the gradual accumulation of particles on the baffle 92.

[0055] In this embodiment, the ratio of the vertical distance from the inlet to the bottom of the filter box 91 to the height of the filter box 91 is 1 / 6 to 1 / 5. This appropriately raises the position of the inlet, preventing the filtrate entering the filter box 91 from directly impacting the bottom of the filter box 91 and causing severe resuspension of sediment.

[0056] In this embodiment, the inlet and liquid inlet of the flow channel 92 are located on the same side of the filter box 91.

[0057] Example 4

[0058] See Figures 1-5 Unlike embodiment 3, in this embodiment, the inlet and liquid inlet of the flow channel 92 are located on opposite sides of the filter box 91. That is, the inlet of the flow channel 92 is located on the left side of the filter box 91, and the liquid inlet is located on the right side of the filter box 91. In this way, the distance between the inlet and liquid inlet of the flow channel 92 is relatively large. Even if there is still a slight resuspension of sediment, the resuspension of sediment will not easily enter the flow channel 92 directly from the inlet of the flow channel 92 due to the obstruction of the bottom baffle 92.

[0059] Finally, it should be noted that the above are merely preferred embodiments of this utility model and are not intended to limit the utility model. For those skilled in the art, this utility model can have various modifications and variations. Without conflict, the embodiments and features described in this application can be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A flue gas treatment system, characterized in that, The application relates to a flue gas pipeline for conveying flue gas with a first specified temperature; a heat exchange water pipeline for conveying industrial water or raw water; a first heat exchange device through which the flue gas pipeline and the heat exchange water pipeline realize heat exchange to heat the industrial water or raw water in the heat exchange water pipeline to a second specified temperature; and a second heat exchange device for heating filtrate in a filtrate tank to 80-90 DEG C. The filtrate tank has a filtrate inlet and a filtrate outlet; the filtrate inlet is sequentially connected with a red mud pressure filtration device for producing alumina, a red mud washing device and a low-temperature leaching device; and the filtrate outlet is connected with the inlet of the low-temperature leaching device through a filtration device. The first heat exchange device comprises a vertical finned tube heat exchanger. The second heat exchange device comprises a heat exchange jacket which is sleeved outside the filtrate tank. The flue gas pipeline is connected with a calcination device for producing alumina. The filtration device comprises a filter box with a liquid inlet and a liquid outlet, wherein the liquid outlet is located above the liquid inlet; and a baffle which is detachably connected to the inner wall of the filter box; wherein a plurality of baffles are longitudinally staggered and arranged between the liquid inlet and the liquid outlet to form an upwardly winding flow channel.

2. The flue gas treatment system of claim 1, wherein, The upper side of the baffle is obliquely arranged.

3. The flue gas treatment system of claim 1, wherein, The ratio of the vertical distance from the liquid inlet to the bottom of the filter box to the height of the filter box is 1 / 6-1 / 5.

4. The flue gas treatment system of claim 1, wherein, The inlet of the flow channel and the liquid inlet are located on opposite sides of the filter box.

5. The flue gas treatment system according to any one of claims 1 to 4, characterized in that, ​ ​ ​ ​ 6. The flue gas treatment system of claim 5, wherein, ​ 7. The flue gas treatment system of claim 5, wherein, ​ 8. The flue gas treatment system of claim 6, wherein, ​

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