Multi-stage heating device for causticizing tank

Abstract

This utility model discloses a multi-stage heating device for a causticizing tank, comprising one or more heating units, the number of which is selected according to the height of the causticizing tank. Each heating unit includes a heating tube, a steam inlet, and a steam outlet. The steam inlet is located at the top of the heating tube, and the side wall of the heating tube has multiple steam outlets communicating with the causticizing tank. During the salt removal and causticizing process, this utility model selects the number of heating tube sets according to the height of the causticizing tank, facilitating disassembly and adjustment, effectively increasing the heating rate, saving steam, and simultaneously effectively avoiding uneven heating within the causticizing tank, resulting in good temperature control.

Description

Technical Field

[0001] This utility model relates to the field of alumina production technology, specifically to a multi-stage heating device for a causticizing tank. Background Technology

[0002] In alumina production, causticization refers to the reaction of sodium carbonate / sodium oxalate and lime slurry to produce calcium carbonate / calcium oxalate and sodium hydroxide. After concentrating the mother liquor to a certain concentration, sodium carbonate / sodium oxalate crystallizes out. Through sedimentation separation, pressure filtration, and water dilution, a solution of appropriate concentration is prepared and sent to a causticization tank for heating. Simultaneously, lime slurry is added to initiate the causticization reaction. The mixed solution needs to remain in the causticization tank for a certain period to ensure the reaction rate. Causticization is a crucial process for removing salts detrimental to the production system and recovering caustic alkali. In recent years, due to the declining grade of bauxite ore and the accumulation of salt content in the production system, affecting the production process and product quality, it is necessary for most alumina plants to add a salt removal causticization process.

[0003] Causticization tanks typically employ direct steam heating, with temperatures controlled between 90℃ and 100℃. Currently, causticization tanks generally use single-stage heating devices, which have poor adjustability for different liquid levels and result in uneven heat distribution. When the tank is at a low liquid level, the single-stage heating device consumes a large amount of steam, leading to energy waste. When the tank is at a high liquid level, the single-stage heating device requires a long heating time, is inefficient, and is detrimental to the causticization reaction. Utility Model Content

[0004] In view of the above-mentioned shortcomings and deficiencies, this utility model provides a multi-stage heating device for a causticizing tank. During the salt discharge and causticizing process, the number of heating tube sleeves is selected according to the height of the causticizing tank, which is convenient for disassembly and adjustment, effectively improves the heating rate, saves steam, and at the same time effectively avoids uneven heating in the causticizing tank, resulting in good temperature control.

[0005] A multi-stage heating device for a causticizing tank is provided in the causticizing tank and includes one or more heating units, the number of which is selected according to the height of the causticizing tank. Each heating unit includes a heating tube, a steam inlet and a steam outlet. The steam inlet is located at the top of the heating tube, and the side wall of the heating tube is provided with multiple steam outlets communicating with the causticizing tank.

[0006] The number of steam outlets is set according to the length of the heating unit, the height difference between the steam outlets is 100-200mm, and the steam outlets are set obliquely downward at an angle of 60° to the center line of the heating tube.

[0007] The bottom of the lowest heating unit is 1000-1500mm away from the bottom of the causticizing tank.

[0008] When multiple heating units are included, the heating units are connected by welding, thread, or flange.

[0009] The heating element is made of carbon steel or stainless steel.

[0010] The beneficial effects of this utility model are as follows:

[0011] This utility model is a multi-stage heating device for a causticizing tank. During the salt discharge and causticizing process, the number of heating tube sleeves is selected according to the height of the causticizing tank, which is convenient for disassembly and adjustment, effectively improves the heating rate, saves steam, and at the same time effectively avoids uneven heating in the causticizing tank, resulting in good temperature control. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a segmented heating device for a causticizing tank according to the present invention.

[0013] Attached diagram: 1 is the steam inlet, 2 is the steam outlet, and 3 is the connecting part. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings. Figure 1 As shown, this utility model discloses a multi-stage heating device for a causticizing tank. During the salt desalination and causticizing process, a multi-stage heating unit group directly heats the solution with steam to reach a certain causticizing temperature. The bottom of the lowest heating unit is 1000-1500mm away from the bottom of the causticizing tank, and the height difference between the steam outlets is 100-200mm. The steam outlets are angled downwards at a 60° angle to the centerline of the heating pipe. A suitable amount of steam is introduced through steam inlet 1, and the steam is introduced into the causticizing tank through steam outlet 2 to heat the solution in the tank. Different heating units are connected by connectors 3. The number of heating unit groups is selected according to the height of the causticizing tank to achieve effective temperature control.

[0015] Example 1

[0016] During the salt removal and causticization process, when a 6m high causticization tank is used for salt removal and causticization, only one heating unit is used. Fresh steam at 0.5MPa is introduced from the steam inlet 1 of the heating pipe, and the steam escapes from the steam outlet 2 into the solution to fully heat the causticization liquid and reach the causticization reaction temperature.

[0017] Example 2

[0018] During the salt removal and causticization process, a 10m high causticization tank is used for salt removal and causticization. Two sets of heating units are connected by threads. Fresh steam at 0.5MPa is introduced from the steam inlet 1 of the heating pipe, and the steam escapes from the steam outlet 2 into the solution to fully heat the causticization liquid and reach the causticization reaction temperature.

[0019] Example 3

[0020] During the salt removal and causticization process, a 12m high causticization tank is used for salt removal and causticization. Three sets of heating units are used, and the three sets of heating units are connected by flanges. Fresh steam at 0.4MPa is introduced from the steam inlet 1 of the heating pipe, and the steam escapes from the steam outlet 2 into the solution to fully heat the causticization liquid to reach the causticization reaction temperature.

[0021] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning of the basic inventive concept, can make other changes and modifications to these embodiments; therefore, the claims should be interpreted as including the preferred embodiments as well as various modifications and variations falling within the scope of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents.

Claims

1. A multi-stage heating device for a causticizing tank, disposed in a causticizing tank, characterized in that, It includes one or more heating units, the number of which is selected according to the height of the causticizing tank; each heating unit includes a heating tube, a steam inlet and a steam outlet, the steam inlet is located at the top of the heating tube, and the side wall of the heating tube is provided with multiple steam outlets communicating with the causticizing tank.

2. The multi-stage heating device for a causticizing tank according to claim 1, characterized in that, The number of steam outlets is set according to the length of the heating unit, the height difference between the steam outlets is 100-200mm, and the steam outlets are set obliquely downward at an angle of 60° to the center line of the heating tube.

3. The multi-stage heating device for a causticizing tank according to claim 1, characterized in that, The bottom of the lowest heating unit is 1000-1500mm away from the bottom of the causticizing tank.

4. The multi-stage heating device for a causticizing tank according to claim 1, characterized in that, When multiple heating units are included, the heating units are connected by welding, thread, or flange.

5. The multi-stage heating device for a causticizing tank according to claim 1, characterized in that, The heating element is made of carbon steel or stainless steel.

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