A titanium dioxide production post-treatment flash drying tower tail gas waste heat recovery system

Abstract

The utility model provides a kind of titanium dioxide production post-treatment flash drying drying tower tail gas waste heat recovery system, belong to titanium dioxide production energy-saving technical field. Including flash drying drying tower, heat exchanger and hot blast stove, heat exchanger includes cylinder, two baffles are equipped in cylinder, to make the first heat exchange cavity, second heat exchange cavity and third heat exchange cavity of cylinder inner chamber division, multiple heat exchange pipes are equipped on two baffles, baffle is provided in the first heat exchange cavity, to make the first heat exchange cavity division into air inlet area and exhaust area, first air inlet for being used to supply tail gas to be worn into is equipped on the outer wall of cylinder in air inlet area, and first exhaust port is equipped in exhaust area, second air inlet and second exhaust port for being used to supply air to pass through are equipped on the outer wall of second heat exchange cavity on the outer wall of cylinder, dust collector is equipped between first air inlet and the exhaust end of flash drying drying tower, tail gas fan is connected at first exhaust port, filter is connected at second air inlet, combustion-supporting fan is connected at second exhaust port. With the effect of energy saving.

Description

Technical Field

[0001] This utility model relates to the field of energy-saving technology in titanium dioxide production, and in particular to a waste heat recovery system for tail gas from a flash drying tower in the post-processing of titanium dioxide production. Background Technology

[0002] Titanium dioxide (TiO2) is an important white pigment widely used in coatings, plastics, papermaking, and other industries. Post-processing steps in its production (such as coating and dispersion) require drying the wet material, often using a flash dryer as the core equipment. The flash dryer uses high-temperature drying gas (usually supplied by a hot air furnace) in direct contact with the wet material to rapidly evaporate moisture and output dried titanium dioxide particles along with hot, humid exhaust gas.

[0003] However, the exhaust gas discharged from the flash drying tower is currently mostly discharged directly through the exhaust gas fan, resulting in a large amount of waste heat being unutilized and causing energy waste. Utility Model Content

[0004] In view of the above problems, this utility model provides a waste heat recovery system for the tail gas of the flash drying tower in the post-processing of titanium dioxide production.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A waste heat recovery system for the tail gas of a flash drying tower in the post-processing of titanium dioxide production is provided, including a flash drying tower, a heat exchanger, and a hot air furnace. The heat exchanger includes a cylindrical body with two baffles spaced apart along its axial direction to sequentially divide the inner cavity of the cylinder into a first heat exchange chamber, a second heat exchange chamber, and a third heat exchange chamber. Multiple heat exchange tubes are arranged on the two baffles to connect the first and third heat exchange chambers. A baffle parallel to its axial direction is arranged in the first heat exchange chamber to divide it into an inlet zone and an exhaust zone. The outer wall of the cylinder is decorated with... The air intake zone is provided with a first air inlet for the exhaust gas to pass through, and the exhaust zone is provided with a first exhaust port. The outer wall of the cylinder is provided with a second air inlet and a second exhaust port for the air to pass through on the outer wall of the second heat exchange chamber. A dust collector for filtering impurities in the exhaust gas is provided between the first air inlet and the exhaust end of the flash drying tower. An exhaust gas fan for auxiliary exhaust is connected to the first exhaust port. A filter for filtering impurities in the air is connected to the second air inlet. A combustion fan for injecting heated air into the hot air furnace is connected to the second exhaust port.

[0006] Furthermore, multiple heat dissipation fins are spaced and alternately arranged along the axial direction of the cylinder on the inner wall of the second heat exchange chamber. Channels for air passage are formed between the multiple heat dissipation fins, and the heat dissipation fins are connected to the outer walls of multiple heat exchange tubes.

[0007] Furthermore, the outlet of the combustion fan is equipped with a temperature sensor for detecting air temperature and a regulating valve for adjusting air flow.

[0008] Furthermore, the bottom of the third heat exchange chamber is connected to a collection box for collecting condensate generated after the exhaust gas is cooled. The collection box is equipped with a drain pipe, and the drain pipe is equipped with a first valve.

[0009] Furthermore, the heat exchange tubes are tilted and the end of the heat exchange tubes near the first heat exchange chamber is higher than the end near the third heat exchange chamber.

[0010] Furthermore, there are two collection boxes, and a connecting pipe is provided at the bottom of the third heat exchange chamber. The connecting pipe is provided with branch pipes for connecting the two collection boxes respectively, and a second valve is provided on the branch pipe.

[0011] The beneficial effects of this invention are as follows: By injecting high-temperature drying gas into the flash drying tower through a hot air furnace, wet materials can be heated into dry titanium dioxide, and wet hot exhaust gas is obtained. The wet hot exhaust gas contains some impurities, which can be filtered by a dust collector. The filtered wet hot exhaust gas can be continuously passed into the heat exchange tube. At the same time, starting the combustion fan can draw room temperature air into the second heat exchange chamber. The air can exchange heat with the wet hot exhaust gas in the heat exchange tube through the second heat exchange chamber. The heated air can be injected into the hot air furnace by the combustion fan. The heat carried by the air can be injected into the hot air furnace for recovery and utilization, which has the effect of saving energy. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of a waste heat recovery system for the tail gas of a flash drying tower in the post-processing of titanium dioxide production, according to an embodiment of this application.

[0013] Figure 2 This is a schematic diagram of the heat exchanger structure of a waste heat recovery system for the tail gas of a flash drying tower in the post-processing of titanium dioxide production, according to an embodiment of this application.

[0014] Figure 3 This application provides a schematic diagram of the internal structure of a heat exchanger in a waste heat recovery system for the tail gas of a flash drying tower during titanium dioxide production.

[0015] The components include: 1. Flash drying tower; 2. Heat exchanger; 21. Shell; 211. Inlet zone; 212. Exhaust zone; 213. Second heat exchange chamber; 214. Third heat exchange chamber; 22. Baffle; 23. Partition plate; 24. Heat exchange tube; 3. Hot air furnace; 4. Dust collector; 5. Exhaust gas fan; 6. Filter; 7. Combustion fan; 8. Heat sink; 9. Temperature sensor; 10. Regulating valve; 20. Collection box; 201. Drain pipe; 202. First valve; 30. Connecting pipe; 301. Branch pipe; 302. Second valve. Detailed Implementation

[0016] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0017] This application discloses a waste heat recovery system for the tail gas of a flash drying tower in the post-processing of titanium dioxide production, referring to... Figure 1 , Figure 2 and Figure 3 The system includes a flash drying tower 1, a heat exchanger 2, and a hot air furnace 3. The heat exchanger 2 includes a cylindrical body 21, inside which two baffles 22 are welded at intervals along its axial direction, dividing the inner cavity of the cylindrical body 21 into a first heat exchange chamber 213 and a third heat exchange chamber 214. Multiple heat exchange tubes 24 are installed on the two baffles 22 to connect the first and third heat exchange chambers 214. A partition 23 parallel to its axial direction is welded inside the first heat exchange chamber, dividing it into an inlet zone 211 and an exhaust zone 212. A first inlet for exhaust gas is provided on the outer wall of the cylindrical body 21 in the inlet zone 211, and a first exhaust port is provided in the exhaust zone 212. A second inlet and a second exhaust port for air passage are provided on the outer wall of the second heat exchange chamber 213. A dust collector 4 for filtering impurities in the exhaust gas is installed between the first air inlet and the exhaust end of the flash drying tower 1. An exhaust gas fan 5 for auxiliary exhaust is connected to the first exhaust port. A filter 6 for filtering impurities in the air is connected to the second air inlet, and a combustion fan 7 for injecting heated air into the hot air furnace 3 is connected to the second exhaust port.

[0018] In this embodiment, high-temperature drying gas is injected into the flash drying tower 1 through the hot air furnace 3, which heats the wet material into dry titanium dioxide and produces humid heat exhaust gas. The humid heat exhaust gas contains some impurities, which can be filtered by the dust collector 4. The filtered humid heat exhaust gas can then continuously pass through the heat exchange tube 24. Simultaneously, the combustion fan 7 is activated to draw room temperature air into the second heat exchange chamber 213. The air passes through the second heat exchange chamber 213 and exchanges heat with the humid heat exhaust gas in the heat exchange tube 24. The heated air can then be injected into the hot air furnace 3 by the combustion fan 7. The heat carried by the air can be recovered and reused in the hot air furnace 3, resulting in energy savings.

[0019] In this embodiment, the dust collector 4 is a bag filter 4, the filter 6 is a filter bag filter 6, and the exhaust fan 5 and the combustion fan 7 are both centrifugal fans.

[0020] Furthermore, multiple heat dissipation fins 8 are spaced apart and alternately arranged on the inner wall of the second heat exchange chamber 213 along the axial direction of the cylinder 21. Channels for air passage are formed between the multiple heat dissipation fins 8, and the heat dissipation fins 8 are connected to the outer wall of multiple heat exchange tubes 24.

[0021] In this embodiment, the heat dissipation area of ​​the heat exchange tube 24 can be increased by using multiple heat sinks 8, thereby increasing the contact area with air and improving the heat absorption effect of the air. The channel formed between the multiple heat sinks 8 can extend the path of air through the second heat exchange chamber 213, further improving the heat absorption effect of the air.

[0022] Furthermore, the outlet of the combustion fan 7 is equipped with a temperature sensor 9 for detecting air temperature and a regulating valve 10 for adjusting air flow.

[0023] In this embodiment, the temperature sensor 9 is functionally connected to a controller, which is functionally connected to the regulating valve 10. When the temperature sensor 9 detects that the temperature of the hot air output by the combustion fan 7 exceeds a preset temperature threshold, the controller controls the regulating valve 10 to increase the outlet diameter of the combustion fan 7, thereby increasing the airflow and accelerating the speed at which air passes through the heat exchange tube 24, thus reducing the air heating temperature. When the temperature sensor 9 detects that the temperature of the hot air output by the combustion fan 7 is lower than the preset temperature threshold, the controller controls the regulating valve 10 to decrease the outlet diameter of the combustion fan 7, thereby decreasing the airflow and slowing the speed at which air passes through the heat exchange tube 24, thus increasing the air heating temperature. This ensures that the air temperature injected into the hot blast furnace 3 is always maintained within the preset temperature threshold, thereby improving the operational stability of the hot blast furnace 3.

[0024] In this embodiment of the application, the controller adopts a computer control system. The preset temperature threshold can be set by the engineer in combination with the heating effect of the hot air furnace 3 and input into the controller.

[0025] In other embodiments of this application, a flow meter (not shown in the figure) for detecting the flow rate of the hot and humid exhaust gas can be installed at the exhaust end of the flash drying tower 1. The flow meter and the exhaust gas fan 5 are respectively connected to a controller. The controller can control the speed of the exhaust gas fan 5 according to the hot and humid exhaust gas flow rate monitored by the flow meter, thereby balancing the pressure in the heat exchange tube 24.

[0026] Furthermore, the bottom of the third heat exchange chamber 214 is connected to a collection box 20 for collecting condensate generated after the exhaust gas is cooled. A drain pipe 201 is connected to the collection box 20, and a first valve 202 is installed on the drain pipe 201.

[0027] In this embodiment, when the humid exhaust gas exchanges heat with the air inside the heat exchange tube 24, the heat dissipation of the humid exhaust gas causes some gaseous water molecules to condense into liquid and flow into the third heat exchange chamber 214, and then into the collection box 20. After the titanium dioxide treatment is completed, the first valve 202 can be opened to recover the moisture. This not only saves resources but also prevents the moisture in the exhaust gas from being directly discharged into the air, affecting the environmental humidity of the factory area.

[0028] In order to facilitate the flow of moisture in the hot and humid air into the third heat exchange chamber 214, the heat exchange tube 24 is inclined and the end of the heat exchange tube 24 near the first heat exchange chamber is higher than the end near the third heat exchange chamber 214.

[0029] Furthermore, there are two collection boxes 20. A connecting pipe 30 is welded to the bottom of the third heat exchange chamber 214. A branch pipe 301 for connecting the two collection boxes 20 is welded to the connecting pipe 30. A second valve 302 is installed on the branch pipe 301.

[0030] During the heat exchange process between the air and the hot, humid exhaust gas, the second valve 302 on one branch pipe 301 is opened, while the second valve 302 on the other branch pipe 301 remains closed. This allows the connected collection box 20 to collect the condensed moisture. Once one collection box 20 is full of moisture, the corresponding second valve 302 is closed, and the other second valve 302 is opened, allowing the collection box 20 to be switched to continue collecting moisture. At this point, the first valve 202 on the full collection box 20 can be opened to recover the moisture. This allows the system to recover moisture without stopping the waste heat recovery process of the hot, humid exhaust gas.

[0031] The implementation principle of the waste heat recovery system for the tail gas of the flash drying tower 1 in the post-processing of titanium dioxide production according to an embodiment of this application is as follows: High-temperature drying gas is injected into the flash drying tower 1 through the hot air furnace 3, which heats the wet material into dry titanium dioxide and produces wet and hot tail gas. The wet and hot tail gas contains some impurities, which can be filtered by the dust collector 4. The filtered wet and hot tail gas can be continuously introduced into the heat exchange tube 24. At the same time, the combustion fan 7 is started to draw room temperature air into the second heat exchange chamber 213. The air can exchange heat with the wet and hot tail gas in the heat exchange tube 24 through the second heat exchange chamber 213. The heated air can be injected into the hot air furnace 3 by the combustion fan 7. The heat carried by the air can be recovered and reused in the hot air furnace 3, which has the effect of saving energy.

[0032] Those skilled in the art will understand that although preferred embodiments of the present invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention. Clearly, those skilled in the art can make various alterations and modifications to the present invention without departing from its spirit and scope. Thus, if these modifications and modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and modifications.

Claims

1. A waste heat recovery system for the tail gas of a flash drying tower in the post-processing of titanium dioxide production, characterized in that: The system includes a flash drying tower (1), a heat exchanger (2), and a hot air furnace (3). The heat exchanger (2) includes a cylindrical body (21). Two baffles (22) are spaced apart along the axial direction inside the cylindrical body (21) to divide the inner cavity of the cylindrical body (21) into a first heat exchange chamber, a second heat exchange chamber (213), and a third heat exchange chamber (214). Multiple heat exchange tubes (24) for connecting the first heat exchange chamber and the third heat exchange chamber (214) are provided on the two baffles (22). A partition (23) parallel to the axial direction is provided inside the first heat exchange chamber to divide the first heat exchange chamber into an air inlet zone (211) and an air outlet zone (212). Outside the cylindrical body (21) The wall has a first air inlet in the air inlet area (211) for the exhaust gas to pass through, and a first exhaust outlet in the exhaust area (212). The outer wall of the cylinder (21) has a second air inlet and a second exhaust outlet on the outer wall of the second heat exchange chamber (213) for the air to pass through. A dust collector (4) for filtering exhaust gas impurities is provided between the first air inlet and the exhaust end of the flash drying tower (1). An exhaust gas fan (5) for auxiliary exhaust is connected to the first exhaust outlet. A filter (6) for filtering impurities in the air is connected to the second air inlet. A combustion fan (7) for injecting heated air into the hot air furnace (3) is connected to the second exhaust outlet.

2. The waste heat recovery system for the tail gas of the flash drying tower in the post-processing of titanium dioxide production according to claim 1, characterized in that: Multiple heat exchange fins (8) are spaced apart and alternately arranged on the inner wall of the second heat exchange chamber (213) along the axial direction of the cylinder (21). A channel for air to pass through is formed between the multiple heat exchange fins (8), and the heat exchange fins (8) are connected to the outer wall of multiple heat exchange tubes (24).

3. The waste heat recovery system for the tail gas of the flash drying tower in the post-processing of titanium dioxide production according to claim 1, characterized in that: The combustion fan (7) is equipped with a temperature sensor (9) for detecting air temperature and a regulating valve (10) for regulating air flow at the air outlet.

4. The waste heat recovery system for the tail gas of the flash drying tower in the post-processing of titanium dioxide production according to claim 1, characterized in that: The bottom of the third heat exchange chamber (214) is connected to a collection box (20) for collecting condensate generated after the exhaust gas is cooled. The collection box (20) is provided with a drain pipe (201) and a first valve (202) is provided on the drain pipe (201).

5. The waste heat recovery system for the tail gas of the flash drying tower in the post-processing of titanium dioxide production according to claim 4, characterized in that: The heat exchange tube (24) is inclined and the end of the heat exchange tube (24) near the first heat exchange chamber is higher than the end near the third heat exchange chamber (214).

6. The waste heat recovery system for the tail gas of the flash drying tower in the post-processing of titanium dioxide production according to claim 4, characterized in that: Two collection boxes (20) are provided. A connecting pipe (30) is provided at the bottom of the third heat exchange chamber (214). A branch pipe (301) for connecting the two collection boxes (20) is provided on the connecting pipe (30). A second valve (302) is provided on the branch pipe (301).

Images