Flue gas treatment system for caustic soda flake production
By using flowing molten salt to contact with hot flue gas for heat exchange and dust interception, combined with a dust collector, the problems of low heat recovery efficiency and dust treatment in caustic soda production are solved, achieving safe and efficient flue gas treatment.
Patent Information
- Application Number
- CN202422722181.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-08
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-11-08
AI Technical Summary
In the existing caustic soda production process, the heat recovery efficiency of hot flue gas is low, dust treatment is difficult, and high-temperature water vapor is highly corrosive. When molten salt is used as the heat transfer medium, the temperature rises further, posing a safety hazard.
Flowing molten salt is used as the heat exchange medium. Heat exchange and dust interception are achieved by contacting hot flue gas with hollow stirring blades. Combined with pre- and post-dust collectors and centrifugal separators, cooling and dust removal are realized.
It improves heat recovery rate, reduces flue gas temperature, effectively removes dust, avoids high-temperature corrosion, and enhances system safety and efficiency.
Smart Images
Figure CN223564815U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of gas treatment, in particular to a flue gas treatment system for flake caustic soda production. BACKGROUND
[0002] In the drying (pyrolysis) stage of the flake caustic soda production process, a large amount of hot flue gas is generated, and the main components of the flue gas are high-temperature gas and dust. The heat in the flue gas is mostly recovered by heat exchange. The heat exchange mode using air as the heat exchange medium has the problem of low heat exchange efficiency. The heat exchange mode using water as the heat exchange medium produces high-temperature and high-pressure steam, and the dust is also dissolved in the steam. The recovery and treatment steps of the high-temperature steam are many, and the high-temperature steam also has certain corrosiveness.
[0003] It also needs to be considered that the current heating starts to use molten salt as a heat transfer medium. The molten salt can provide higher temperature and shorten the drying (pyrolysis) time, but it also further increases the temperature of the hot flue gas. SUMMARY
[0004] The application provides a flue gas treatment system for flake caustic soda production. The flowing molten salt is used as the heat exchange medium. The molten salt can absorb and store the heat in the hot flue gas, and can also intercept the dust in the hot flue gas to a certain extent. The hot flue gas can be cooled and dedusted at the same time.
[0005] The above object of the application is achieved by the following technical scheme:
[0006] The application provides a flue gas treatment system for flake caustic soda production, comprising:
[0007] The shell has an exhaust end, a feeding end and a discharge end;
[0008] The hollow rotating shaft is rotatably connected to the shell. The first end of the hollow rotating shaft is an open end, and the second end of the hollow rotating shaft is a closed end;
[0009] The hollow stirring paddle is arranged on the hollow rotating shaft in a spaced manner. The cavity in the hollow stirring paddle is in communication with the cavity in the hollow rotating shaft;
[0010] The exhaust hole is arranged on the hollow stirring paddle and is in communication with the cavity in the hollow stirring paddle;
[0011] The molten salt particles are filled in the shell;
[0012] The driver is connected to the hollow rotating shaft and is used to drive the rotation of the hollow rotating shaft and the hollow stirring paddle.
[0013] In a possible implementation of the present application, the pre-cyclone dust collector is further included, and a gas output end of the pre-cyclone dust collector is connected with the first end of the hollow rotating shaft.
[0014] In a possible implementation of the present application, the post-cyclone dust collector is further included, and an input end of the post-cyclone dust collector is connected with the exhaust end.
[0015] In a possible implementation of the present application, the width of the hollow stirring paddle tends to increase in the direction opposite to the rotating direction of the hollow rotating shaft.
[0016] In a possible implementation of the present application, the first end of the exhaust hole is in communication with the cavity inside the hollow stirring paddle, and the second end of the exhaust hole is inclined away from the rotating direction of the hollow rotating shaft.
[0017] In a possible implementation of the present application, the centrifugal separator is further included, and an input end of the centrifugal separator is connected with the discharge end, and an output end of the centrifugal separator is connected with the feeding end.
[0018] In a possible implementation of the present application, the centrifugal separator comprises a positive pressure blower, a positive pressure accelerator and a cyclone separator connected in sequence.
[0019] The heavy material output end of the cyclone separator is connected with the feeding end.
[0020] The flue gas treatment system for flake caustic soda production provided by the present application uses flowing molten salt as a heat exchange medium, and the hot flue gas and the molten salt are in full contact inside the shell to complete the heat exchange process. At the same time, part of the dust in the hot flue gas will also be left in the molten salt. The cooled hot flue gas can be sent to a bag filter for treatment, and then spray heat recovery is performed. This way can effectively improve the heat recovery rate. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 is a structural schematic diagram of a flue gas treatment system for flake caustic soda production provided by the present application.
[0022] Figure 2 is a flue gas flow path schematic diagram given based on Figure 1 .
[0023] Figure 3 is a connection schematic diagram of a hollow rotating shaft and a hollow stirring paddle provided by the present application.
[0024] Figure 4 is a structural schematic diagram of a centrifugal separator provided by the present application.
[0025] Figure 5 is a molten salt particle flow path schematic diagram given based on Figure 4 .
[0026] In the figure, 1, shell, 2, hollow rotating shaft, 3, hollow stirring paddle, 4, exhaust hole, 5, molten salt particles, 6, driver, 7, pre-cyclone dust collector, 8, post-dust collector, 9, centrifugal separator, 11, exhaust end, 12, feeding end, 13, discharge end, 91, positive pressure blower, 92, positive pressure accelerator, 93, cyclone separator. DETAILED DESCRIPTION
[0027] The technical solutions in the application will be further described in detail below with reference to the drawings.
[0028] The application discloses a flue gas treatment system for flake caustic soda production. Figure 1 and Figure 2 In some examples, the flue gas treatment system for flake caustic soda production disclosed by the application comprises a shell 1, a hollow rotating shaft 2, a hollow stirring paddle 3, and a driver 6.
[0029] The shell 1 is provided with an exhaust end 11, a feeding end 12 and a discharge end 13. The exhaust end 11 is used to discharge the flue gas inside the shell 1 after temperature reduction treatment. The feeding end 12 is used to inject molten salt into the shell 1. The discharge end 13 is used to guide the molten salt out of the shell 1.
[0030] The hollow rotating shaft 2 is rotationally connected with the shell 1. The first end of the hollow rotating shaft 2 is an open end, and the second end of the hollow rotating shaft 2 is a closed end. The hollow stirring paddles 3 are arranged on the hollow rotating shaft 2 at intervals. The cavities in the hollow stirring paddles 3 are in communication with the cavity in the hollow rotating shaft 2. After the high-temperature flue gas enters the hollow rotating shaft 2, it will re-enter the hollow stirring paddles 3, and then be discharged through the exhaust holes on the hollow stirring paddles 3.
[0031] The driver 6 is connected with the hollow rotating shaft 2. The driver 6 is used to drive the rotation of the hollow rotating shaft 2 and the hollow stirring paddles 3. In some possible implementation manners, the driver 6 uses an electric motor. The driver 6 and the hollow rotating shaft 2 are connected in a belt drive mode.
[0032] The molten salt particles 5 are filled in the shell 1. After the high-temperature flue gas discharged from the exhaust hole 4 is in contact with the molten salt particles 5, heat exchange is performed. At this time, the temperature of the high-temperature flue gas is reduced, and the high-temperature flue gas is converted into low-temperature flue gas. The temperature of the molten salt particles 5 rises.
[0033] In the above process, the dust in the high-temperature flue gas, mainly sodium hydroxide powder, also stays in the molten salt particles 5. The low-temperature flue gas flows out of the exhaust end 11. The molten salt particles 5 flow circularly through the feeding end 12 and the discharge end 13. After the molten salt particles 5 are transferred to the outside of the shell 1, they are subjected to temperature reduction treatment and separation treatment. The purpose of the separation treatment is to remove the sodium hydroxide powder in the molten salt particles 5.
[0034] In some examples, a pre-cyclone dust collector 7 is also added, and the gas output end of the pre-cyclone dust collector 7 is connected with the first end of the hollow rotating shaft 2. The purpose of the pre-cyclone dust collector 7 is to remove the large-particle-size sodium hydroxide powder in the high-temperature flue gas, so as to avoid that the large-particle-size sodium hydroxide powder cannot be removed when the molten salt particles 5 are separated and treated.
[0035] In some examples, a post-cyclone dust collector 8 is added, and the input end of the post-cyclone dust collector 8 is connected with the exhaust end 11, which functions to remove the sodium hydroxide powder in the low-temperature flue gas. Since the temperature of the low-temperature flue gas has been greatly reduced at this time, the post-cyclone dust collector 8 can use a bag dust collector.
[0036] In some examples, the width of the hollow stirring paddle 3 tends to increase in the direction opposite to the rotating direction of the hollow rotating shaft 2, so as to reduce the resistance received by the hollow stirring paddle 3 when rotating.
[0037] Meanwhile, please refer to Figure 3 ( Figure 3 The dashed line at the exhaust hole 4 indicates that the exhaust hole 4 is obliquely arranged. The first end of the exhaust hole 4 is in communication with the cavity inside the hollow stirring paddle 3, and the second end of the exhaust hole 4 is obliquely arranged in the direction away from the rotating direction of the hollow rotating shaft 2, so as to avoid that the molten salt particles 5 enter the inside of the hollow stirring paddle 3.
[0038] In some examples, please refer to Figure 4 and Figure 5 A centrifugal separator 9 is also added, and the input end of the centrifugal separator 9 is connected with the discharge end 13, and the output end is connected with the feeding end 12, which functions to separate the molten salt particles 5 and the sodium hydroxide powder mixed in the molten salt particles 5.
[0039] The centrifugal separator 9 includes three parts, which are a positive pressure blower 91, a positive pressure accelerator 92 and a cyclone separator 93, which are sequentially connected. The heavy material output end of the cyclone separator 93 is connected with the feeding end 12, and the light material output end of the cyclone separator 93 can be directly connected with the post-cyclone dust collector 8.
[0040] The positive pressure accelerator 92 is composed of an air compressor and an air tank, which functions to inject high-pressure air into the pipeline, so as to further increase the flow speed of the molten salt particles 5.
[0041] The embodiments of the specific implementation are the preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, any equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.
Claims
1. A flue gas treatment system for caustic soda production, characterized by, The utility model relates to a molten salt particle drying device, comprising: a shell (1) having an exhaust end (11), a feeding end (12) and a discharge end (13); a hollow rotating shaft (2) rotatably connected to the shell (1), the first end of the hollow rotating shaft (2) being an open end, and the second end of the hollow rotating shaft (2) being a closed end; a hollow stirring paddle (3) arranged at intervals on the hollow rotating shaft (2), the hollow cavity inside the hollow stirring paddle (3) being in communication with the hollow cavity inside the hollow rotating shaft (2); an exhaust hole (4) provided on the hollow stirring paddle (3), the exhaust hole (4) being in communication with the hollow cavity inside the hollow stirring paddle (3); molten salt particles (5) filled inside the shell (1); a driver (6) connected to the hollow rotating shaft (2), the driver (6) being used to drive the hollow rotating shaft (2) and the hollow stirring paddle (3) to rotate.
2. The flue gas treatment system for producing sheet alkali according to claim 1, characterized by It further comprises a pre-cyclone dust collector (7), the gas output end of the pre-cyclone dust collector (7) being connected to the first end of the hollow rotating shaft (2).
3. The flue gas treatment system for producing soda by the process according to claim 1 or 2, characterized in that, It further comprises a post-dust collector (8), the input end of the post-dust collector (8) being connected to the exhaust end (11).
4. The flue gas treatment system for producing sheet alkali according to claim 1, characterized by The width of the hollow stirring paddle (3) tends to increase in the direction opposite to the rotating direction of the hollow rotating shaft (2).
5. The flue gas treatment system for producing sheet alkali according to claim 4, characterized by The first end of the exhaust hole (4) is in communication with the hollow cavity inside the hollow stirring paddle (3), and the second end of the exhaust hole (4) is inclined in the direction away from the rotating direction of the hollow rotating shaft (2).
6. The flue gas treatment system for producing sheet alkali according to claim 1, characterized by It further comprises a centrifugal separator (9), the input end of the centrifugal separator (9) being connected to the discharge end (13), and the output end of the centrifugal separator (9) being connected to the feeding end (12).
7. The flue gas treatment system for producing sheet alkali according to claim 6, characterized by The centrifugal separator (9) comprises a positive pressure blower (91), a positive pressure accelerator (92) and a cyclone separator (93) connected in sequence. The heavy material output end of the cyclone separator (93) is connected to the feeding end (12).