Controllable cooling method for titanium dioxide gas-solid suspension system

Abstract

The invention discloses a controllable cooling method of a titanium dioxide gas-solid suspension system. The method comprises the following steps: first-stage cooling: reducing the temperature of the gas-solid suspension system from 1500 DEG C or above to 1100-1200 DEG C; second-stage cooling: reducing the temperature of the gas-solid suspension system from 1100-1200 DEG C to 650-750 DEG C; third-stage cooling: reducing the temperature of the gas-solid suspension system from 650 DEG C to 750 DEG C to 150 DEG C to 200 DEG C; and fourth-stage cooling: reducing the temperature of the gas-solid suspension system from 150-200 DEG C to 100 DEG C or below. According to the method, cooling is controlled by stages, so that micro-cracks generated in powder particles due to too high cooling rate are avoided, the compactness after sintering is ensured not to be affected, powder agglomeration and growth due to too low cooling rate are avoided, and the adverse effect of the cooling process on particle size distribution is avoided.

Description

Technical Field

[0001] This invention relates to the field of industrial high-temperature material handling technology, and in particular to a controllable cooling method for a titanium dioxide gas-solid suspension system. Background Technology

[0002] Gas-solid suspension systems refer to mixed systems in which solid particles disperse, flow, or react under the action of airflow, and are widely used in chemical, energy, materials, and environmental protection fields. In a titanium dioxide gas-solid suspension system, the solid is titanium dioxide, and the gases include chlorine, nitrogen, and oxygen. During the cooling process from 1500℃ to below 100℃, various uncontrollable phenomena may occur, affecting the performance and structural integrity of the final product. The control of this process involves multiple disciplines such as fluid mechanics, heat and mass transfer, and chemical reaction engineering. When the cooling rate is too fast, microcracks may form inside the powder particles due to uneven thermal shrinkage, even leading to particle breakage and affecting the density after sintering. When the cooling rate is too slow, the powder may further agglomerate and grow abnormally, disrupting the particle size distribution.

[0003] Therefore, existing technologies still need improvement. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a controllable cooling method for a titanium dioxide gas-solid suspension system, thereby resolving the technical issues existing in the cooling process of the titanium dioxide gas-solid suspension system in the prior art.

[0005] To address the aforementioned technical problems, some embodiments of the present invention disclose a controllable cooling method for a titanium dioxide gas-solid suspension system, comprising: The first stage of cooling: reducing the temperature of the gas-solid suspension system from above 1500℃ to 1100~1200℃; The second stage of cooling: reducing the temperature of the gas-solid suspension system from 1100~1200℃ to 650℃~750℃; The third stage of cooling: reducing the temperature of the gas-solid suspension system from 650℃~750℃ to 150℃~200℃; The fourth stage of cooling involves reducing the temperature of the gas-solid suspension system from 150℃~200℃ to below 100℃.

[0006] Furthermore, the first stage of cooling uses a water-cooled jacket for cooling.

[0007] Furthermore, the second stage of cooling employs a counter-current cooling tubular heat exchanger unit for cooling.

[0008] Furthermore, the third stage of cooling employs a counter-current cooling tubular heat exchanger unit for cooling.

[0009] Furthermore, the fourth stage of cooling employs a gas-solid separation device for cooling.

[0010] Furthermore, during the first stage of cooling, the temperature field distribution of the outer wall is fed back in real time by an infrared thermal imager, and the cooling rate is adjusted by the established control model; and the time taken for the gas-solid suspension system to cool in the first stage is 10ms~500ms.

[0011] Furthermore, during the second stage of cooling, a thermocouple temperature measuring device is installed at the outlet of the cooling device to monitor the temperature of the gas-solid suspension system in real time, establish a correlation model between system temperature and cooling water flow rate, and use a fuzzy PID control algorithm to achieve precise temperature control; and the time taken for the gas-solid suspension system to cool in the second stage is 100ms~1000ms.

[0012] Furthermore, during the third stage of cooling, a thermocouple temperature measuring device is installed at the outlet of the cooling device to monitor the temperature of the gas-solid suspension system in real time, establish a correlation model between system temperature and cooling water flow rate, and use a fuzzy PID control algorithm to achieve precise temperature control. Moreover, the time taken for the gas-solid suspension system to cool down in the third stage is 1s to 5s.

[0013] Furthermore, during the fourth stage of cooling, a bag filter is used for gas-solid separation to complete the cooling process.

[0014] Furthermore, during the second and third stages of cooling, the warm water flowing out of the cooling device enters the boiler system to generate steam for driving the refrigeration unit.

[0015] By adopting the above technical solution, the present invention has at least the following beneficial effects: The present invention provides a controllable cooling method for a titanium dioxide gas-solid suspension system. By controlling the cooling in stages, the method avoids the formation of microcracks inside the powder particles due to excessively rapid cooling, thereby ensuring that the compactness after sintering is not affected. It also avoids the agglomeration and growth of powder due to excessively slow cooling, thereby avoiding the adverse effects of the cooling process on the particle size distribution. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of a controllable cooling method for a titanium dioxide gas-solid suspension system disclosed in some embodiments of the present invention. Detailed Implementation

[0018] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0019] These embodiments are provided in this disclosure to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0020] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure 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, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0022] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0023] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0024] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0025] like Figure 1 As shown in the figure, this invention discloses a controllable cooling method for a titanium dioxide gas-solid suspension system. Based on the characteristics of chloride-process titanium dioxide powder, this method establishes a four-stage gradient cooling system, which can obtain titanium dioxide with a better particle size distribution. The first gradient temperature control mode uses a spray-cooling method to reduce the temperature of the gas-solid suspension system from above 1500℃ to 1100℃-1200℃; the second gradient temperature control mode uses tubular heat exchanger group A to reduce the temperature from 1100℃-1200℃ to 650℃-750℃; the third gradient temperature control mode uses tubular heat exchanger group B to reduce the temperature from 650℃-750℃ to 150℃-200℃; the fourth gradient temperature control mode uses a gas-solid separation device to reduce the temperature from 150℃-200℃ to below 100℃, achieving gas-solid separation.

[0026] The above embodiments of the present invention control the cooling in stages to avoid the formation of microcracks inside the powder particles due to excessively rapid cooling, thereby ensuring that the compactness after sintering is not affected, and to avoid the agglomeration and growth of powder due to excessively slow cooling, thereby avoiding the adverse effects of the cooling process on the particle size distribution.

[0027] Example 1 A controllable cooling method for a titanium dioxide gas-solid suspension system is disclosed. The first gradient temperature control mode employs rapid quenching to reduce the temperature from over 1580℃ to 1100℃. Since the titanium dioxide produced via the chloride process is a continuous, uninterrupted feed, the material is transported within 200ms in the first stage. This gradient utilizes a sheathed device. Inside the pipe, the gas-solid suspension system is supplied by spraying a gas-solid mixed cold material, while outside the pipe, a water-cooled jacket uses flowing chilled brine. Due to the high temperature of the first gradient, traditional thermocouples may fail due to material melting, oxidation, or signal drift. The temperature field distribution on the outer wall is fed back in real-time using an infrared thermal imager. Based on the established control model, the cooling rate is adjusted by regulating the chilled brine, cold material, and cooling air.

[0028] The second-gradient temperature control mode utilizes a counter-current cooling water tubular heat exchanger assembly. Thermocouples (used for temperature measurement) are placed at the pipe ends to monitor the temperature of the gas-solid suspension system in real time. A correlation model between system temperature and cooling water flow rate is established, and a fuzzy PID control algorithm is employed to achieve an accuracy of ±5℃, thus enabling precise temperature control for each pipe section. Since the titanium dioxide material from the chloride process flows continuously, the material is fed through tubular heat exchanger assembly A in the second-stage temperature control mode, reducing the temperature from 1100℃ to 700℃ in 500ms. (The flow rate and temperature control range of the chilled brine depend entirely on the established temperature-cooling water flow rate correlation model; higher temperatures result in increased cooling water flow rate, and lower temperatures result in decreased cooling water flow rate.) The third-gradient temperature control mode employs a counter-current cooling water cooling tubular heat exchanger assembly. Thermocouples are placed at the pipe ends to monitor the temperature of the gas-solid suspension system in real time. A correlation model between system temperature and cooling water flow rate is established. Unlike the second-gradient temperature control mode, it also uses a fuzzy PID control algorithm to achieve an accuracy of ±5℃, ensuring precise temperature control for each pipe section. The temperature was reduced from 700℃ to 150℃ in 3 seconds.

[0029] The fourth-gradient temperature control mode uses a gas-solid separation device to reduce the temperature from 150℃ to below 98℃, achieving gas-solid separation. The gas-solid separation device mentioned here refers to a high-efficiency filter, preferably a bag filter.

[0030] Among them, the temperature-controlled water flowing out of the system in the second and third gradient temperature control modes enters the boiler system to generate steam, which is used to drive the refrigeration unit and reduce the water temperature entering the tubular heat exchanger group.

[0031] Tests showed that the titanium dioxide powder particles were distributed in the range of 100nm to 400nm, with more than 70% distributed in the range of 150nm to 300nm.

[0032] Example 2 A controllable cooling method for a titanium dioxide gas-solid suspension system is disclosed. The first gradient temperature control mode employs rapid quenching to reduce the temperature from above 1530℃ to 1200℃. Since the titanium dioxide produced via the chloride process is a continuous, uninterrupted feed, the material is transported in the first stage within 100ms. This gradient utilizes a sheathed device. Inside the pipe, the gas-solid suspension system is supplied with a sprayed gas-solid mixed cold material, while a water-cooled jacket outside the pipe uses flowing chilled brine. Due to the high temperature of the first gradient, traditional thermocouples may fail due to material melting, oxidation, or signal drift. The temperature field distribution on the outer wall is fed back in real-time using an infrared thermal imager. Based on the established control model, the cooling rate is adjusted by regulating the chilled brine, cold material, and cooling air. (The pipe diameter is affected by production line capacity and should not be a limiting factor in this invention.) The second-gradient temperature control mode utilizes a counter-current cooling water tubular heat exchanger assembly. Thermocouples (used for temperature measurement) are placed at the pipe ends to monitor the temperature of the gas-solid suspension system in real time. A correlation model between system temperature and cooling water flow rate is established, and a fuzzy PID control algorithm is employed to achieve an accuracy of ±5℃, thus enabling precise temperature control for each pipe section. Since the titanium dioxide material from the chloride process flows continuously, the material is fed through tubular heat exchanger assembly A in the second-stage temperature control mode, reducing the temperature from 1200℃ to 650℃ in 100ms. (The flow rate and temperature control range of the chilled brine depend entirely on the established temperature-cooling water flow rate correlation model; higher temperatures result in increased cooling water flow rate, and lower temperatures result in decreased cooling water flow rate.) The third-gradient temperature control mode employs a counter-current cooling water cooling tubular heat exchanger assembly. Thermocouples are placed at the pipe ends to monitor the temperature of the gas-solid suspension system in real time. A correlation model between system temperature and cooling water flow rate is established. Unlike the second-gradient temperature control mode, it also uses a fuzzy PID control algorithm to achieve an accuracy of ±5℃, ensuring precise temperature control for each pipe section. The temperature was reduced from 650℃ to 200℃ in 5 seconds.

[0033] The fourth-gradient temperature control mode uses a gas-solid separation device to reduce the temperature from 200℃ to 93℃, achieving gas-solid separation. The gas-solid separation device mentioned here refers to a high-efficiency filter, preferably a bag filter.

[0034] Among them, the temperature-controlled water flowing out of the system in the second and third gradient temperature control modes enters the boiler system to generate steam, which is used to drive the refrigeration unit and reduce the water temperature entering the tubular heat exchanger group.

[0035] Tests showed that the titanium dioxide powder particles were distributed in the range of 100nm to 400nm, with more than 70% distributed in the range of 150nm to 300nm.

[0036] Example 3 A controllable cooling method for a titanium dioxide gas-solid suspension system is disclosed. The first gradient temperature control mode employs rapid quenching to reduce the temperature from over 1560℃ to 1200℃. Since the titanium dioxide produced via the chloride process is a continuous, uninterrupted feed, the material is transported within 500ms in the first stage. This gradient utilizes a sheathed device. Inside the pipe, the gas-solid suspension system is supplied with a sprayed gas-solid mixed cold material, while a water-cooled jacket outside the pipe uses flowing chilled brine. Due to the high temperature of the first gradient, traditional thermocouples may fail due to material melting, oxidation, or signal drift. The temperature field distribution on the outer wall is fed back in real-time by an infrared thermal imager. Based on an established control model, the cooling rate is adjusted by regulating the chilled brine, cold material, and cooling air. (The pipe diameter is affected by production line capacity and should not be a limiting factor in this invention.) The second-gradient temperature control mode utilizes a counter-current cooling water tubular heat exchanger assembly. Thermocouples (used for temperature measurement) are placed at the pipe ends to monitor the temperature of the gas-solid suspension system in real time. A correlation model between system temperature and cooling water flow rate is established, and a fuzzy PID control algorithm is employed to achieve an accuracy of ±5℃, thus enabling precise temperature control for each pipe section. Since the titanium dioxide material from the chloride process flows continuously, the material is fed through tubular heat exchanger assembly A in the second-stage temperature control mode, reducing the temperature from 1200℃ to 750℃ in 1000ms. (The flow rate and temperature control range of the chilled brine depend entirely on the established temperature-cooling water flow rate correlation model; higher temperatures result in increased cooling water flow rate, and lower temperatures result in decreased cooling water flow rate.) The third-gradient temperature control mode employs a counter-current cooling water cooling tubular heat exchanger assembly. Thermocouples are placed at the pipe ends to monitor the temperature of the gas-solid suspension system in real time. A correlation model between system temperature and cooling water flow rate is established. Unlike the second-gradient temperature control mode, it also uses a fuzzy PID control algorithm to achieve an accuracy of ±5℃, ensuring precise temperature control for each pipe section. The temperature was reduced from 750℃ to 200℃ in 1 second.

[0037] The fourth-gradient temperature control mode uses a gas-solid separation device to reduce the temperature from 200℃ to below 100℃, achieving gas-solid separation. This gas-solid separation device refers to a high-efficiency filter, preferably a bag filter.

[0038] Among them, the temperature-controlled water flowing out of the system in the second and third gradient temperature control modes enters the boiler system to generate steam, which is used to drive the refrigeration unit and reduce the water temperature entering the tubular heat exchanger group.

[0039] Tests showed that the titanium dioxide powder particles were distributed in the range of 100nm to 400nm, with more than 70% distributed in the range of 150nm to 300nm.

[0040] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0041] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A controllable cooling method for a titanium dioxide gas-solid suspension system, characterized in that, include: The first stage of cooling: reducing the temperature of the gas-solid suspension system from above 1500℃ to 1100~1200℃; The second stage of cooling: reducing the temperature of the gas-solid suspension system from 1100~1200℃ to 650℃~750℃; The third stage of cooling: reducing the temperature of the gas-solid suspension system from 650℃~750℃ to 150℃~200℃; The fourth stage of cooling involves reducing the temperature of the gas-solid suspension system from 150℃~200℃ to below 100℃.

2. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, The first stage of cooling uses a water-cooled jacket for cooling.

3. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, The second stage of cooling uses a counter-current cooling tubular heat exchanger unit for cooling.

4. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, The third stage of cooling uses a counter-current cooling tubular heat exchanger unit for cooling.

5. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, The fourth stage of cooling uses a gas-solid separation device.

6. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, During the first stage of cooling, the temperature field distribution of the outer wall is fed back in real time by an infrared thermal imager, and the cooling rate is adjusted by the established control model; and the time taken for the gas-solid suspension system to cool in the first stage is 10ms~500ms.

7. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, During the second stage of cooling, a thermocouple temperature measuring device is installed at the outlet of the cooling device to monitor the temperature of the gas-solid suspension system in real time, establish a correlation model between system temperature and cooling water flow rate, and use a fuzzy PID control algorithm to achieve precise temperature control; and the time taken for the gas-solid suspension system to cool in the second stage is 100ms~1000ms.

8. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, During the third stage of cooling, a thermocouple temperature measuring device is installed at the outlet of the cooling device to monitor the temperature of the gas-solid suspension system in real time. A correlation model between the system temperature and the cooling water flow rate is established, and a fuzzy PID control algorithm is used to achieve precise temperature control. Furthermore, the cooling time of the gas-solid suspension system in the third stage is 1 to 5 seconds.

9. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, In the fourth stage of cooling, a bag filter is used for gas-solid separation to complete the cooling process.

10. The controllable cooling method for the titanium dioxide gas-solid suspension system according to claim 1, characterized in that, During the second and third stages of cooling, the warm water flowing out of the cooling device enters the boiler system to generate steam for driving the refrigeration unit.

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