Temperature-controlled gravity dust collector, method for treating dust-laden flue gas

Abstract

The present application relates to the technical field of flue gas treatment, and especially relates to a temperature control type gravity dust collector and a treatment method of dust-containing flue gas. The temperature control type gravity dust collector comprises a gravity dust collector main structure; the gravity dust collector main structure comprises a gas inlet pipe I section, a dust collecting tank II section and a gas outlet pipe III section connected in sequence; a wind channel is arranged outside the gravity dust collector main structure; a spiral ascending wind channel is arranged outside the gas inlet pipe I section, the dust collecting tank II section and the gas outlet pipe III section; the lower end of the wind channel is an air inlet; and the upper end of the wind channel is an air outlet. The present application can meet the temperature regulation and control requirements of dust-containing flue gas under complex working conditions, can adjust the temperature and the air speed of the air inlet according to requirements, and can control the wall surface temperature of the gravity dust collector, so as to realize the functions of dust-containing flue gas cooling, heat preservation and heating.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment technology, and in particular to a temperature-controlled gravity dust collector and a method for treating dust-laden flue gas. Background Technology

[0002] Currently, the main method for producing titanium tetrachloride is the fluidized bed chlorination process. This involves mixing TiO2-rich titanium raw materials with petroleum coke in a specific ratio, adding chlorine gas, and conducting a closed chemical reaction in a chlorination furnace. The reaction temperature is generally above 900℃, and titanium tetrachloride is obtained upon completion of the reaction. However, due to the natural endowment of titanium-bearing ore in my country, the main natural ore is vanadium-titanium magnetite, which has high calcium and magnesium content. The traditional fluidized bed chlorination process requires titanium raw materials with a TiO2 content ≥90% and a CaO and MgO content ≤1.5%, resulting in high processing costs, a long process, and significant challenges. After years of dedicated research, Panzhihua Iron and Steel Group (Pangang) has gradually developed a process route for simultaneously producing titanium tetrachloride from titanium-bearing blast furnace slag, primarily using a "high-temperature carbonization-low-temperature chlorination" process.

[0003] The mixed gas exiting the low-temperature chlorination furnace mainly consists of TiCl4, but also contains impurities such as FeCl3. To obtain relatively pure TiCl4, it is necessary to first remove impurities such as FeCl3 from the steam. Gravity dust collectors have a simple structure and good corrosion resistance. Through reasonable structural design, they can achieve a certain cooling effect, condensing high-boiling-point impurities such as FeCl3 in the steam and depositing them together with the entrained solid particles, thereby achieving a dust removal effect. Patent application CN202310633004.2 discloses a cooling gravity dust collector and a treatment system and method for high-temperature dust-laden gas. The designed gravity dust collector is divided into a cylinder and a hopper, including an inlet channel, an outlet channel, and a baffle. A cooling water flow channel is formed between the inlet channel, the outlet channel, and the cylinder to cool the high-temperature dust-laden gas. Patent application CN202221778612.X discloses a gravity dust collector for use in the production technology of titanium tetrachloride. The cylindrical body is designed as a double-layer structure, with coolant flowing between the layers. An impact device is installed inside the cylinder to strike the inner wall, causing impurities adhering to the inner wall to fall off. However, all of these patents suffer from drawbacks such as inability to precisely control temperature, lack of segmented cooling, and inability to control the temperature of flue gas. Furthermore, the process requires switching between cooling, maintaining, and heating the dust-laden flue gas, or frequently switching between these three conditions, which cannot be effectively controlled. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a temperature-controlled gravity dust collector and a method for treating dust-laden flue gas. The present invention can meet the requirements for temperature control of dust-laden flue gas under complex working conditions.

[0005] This invention provides a temperature-controlled gravity dust collector, comprising:

[0006] The main structure of the gravity dust collector includes an inlet pipe section I, an ash collection tank section II, and an outlet pipe section III connected in sequence.

[0007] An air duct is provided outside the main structure of the gravity dust collector: a spiral air duct is provided outside the inlet pipe section I, the ash collection tank section II, and the outlet pipe section III. The lower end of the air duct is the air inlet, and the upper end of the air duct is the air outlet.

[0008] Preferably, the intake pipe section I is vertically arranged, with a flue gas inlet at the top and a flue gas outlet at the bottom;

[0009] The ash collection tank section II is an inverted cone structure with a dust outlet at the bottom and a flue gas inlet and outlet at the top; the flue gas inlet of the ash collection tank section II is connected to the flue gas outlet of the air inlet pipe section I.

[0010] The exhaust pipe section III is vertically arranged, with a flue gas inlet at the bottom and a flue gas outlet at the top; the flue gas inlet of the exhaust pipe section III is connected to the flue gas outlet of the ash collection tank section II.

[0011] Preferably, the intake pipe section I is a cylindrical pipe or a rectangular pipe;

[0012] The exhaust pipe section III is a cylindrical pipe or a rectangular pipe.

[0013] The present invention also provides a method for treating dust-laden flue gas, comprising the following steps:

[0014] The dust-laden flue gas is sequentially passed through the inlet pipe section I, the ash collection tank section II, and the outlet pipe section III of a temperature-controlled gravity dust collector to obtain the treated flue gas;

[0015] The temperature-controlled gravity dust collector is the same as the temperature-controlled gravity dust collector described above.

[0016] Preferably, in the dust-laden flue gas, the mass content of TiCl4 is ≥90%, the mass content of FeCl3 is 7% to 9%, and the mass content of particulate matter is 1% to 10%.

[0017] Preferably, the temperature of the dust-laden flue gas is 260–950°C.

[0018] Preferably, the cold air temperature at the air inlet of section I of the air inlet pipe is controlled to be room temperature, and the wind speed is 8-10 m / s; the cold air temperature at the air inlet of section II of the ash collection tank is controlled to be 150-220℃, and the wind speed is 5-6 m / s; the cold air temperature at the air inlet of section III of the air outlet pipe is controlled to be room temperature, and the wind speed is 6-8 m / s.

[0019] Preferably, the cold air temperature at the air inlet of section I of the air inlet pipe is controlled at 330-400℃, and the air velocity is 0-3m / s, and not 0; the cold air temperature at the air inlet of section II of the ash collection tank is controlled at 330-400℃, and the air velocity is 0-3m / s, and not 0; the cold air temperature at the air inlet of section III of the air outlet pipe is controlled at 330-400℃, and the air velocity is 0-3m / s, and not 0.

[0020] Preferably, the cold air temperature at the air inlet of section I of the air inlet pipe is controlled at 310-350℃, and the air velocity is 5-10m / s; the cold air temperature at the air inlet of section II of the ash collection tank is controlled at 310-350℃, and the air velocity is 5-10m / s; the cold air temperature at the air inlet of section III of the air outlet pipe is controlled at 310-350℃, and the air velocity is 5-10m / s.

[0021] Preferably, the inner wall temperature of the main structure of the gravity dust collector is controlled at 220–380°C.

[0022] This invention provides a temperature-controlled gravity dust collector, comprising: a main structure for the gravity dust collector; the main structure includes an inlet pipe section I, a dust collection tank section II, and an outlet pipe section III connected in sequence; and an air duct is provided outside the main structure: a spirally rising air duct is provided outside the inlet pipe section I, the dust collection tank section II, and the outlet pipe section III, with the lower end of the air duct being the air inlet and the upper end being the air outlet. This invention allows for adjustment of the inlet temperature and air velocity as needed, controlling the wall temperature of the gravity dust collector, thereby achieving the functions of cooling, heat preservation, and heating of dust-laden flue gas. Typically, when used to remove impurities such as FeCl3 from titanium tetrachloride vapor, the wall temperature of the gravity dust collector is controlled at 220℃~300℃. Dust-laden hot flue gas is fed into the temperature-controlled gravity dust collector through the inlet. After condensation, the FeCl3 gas in the flue gas adheres to the surface of the dust particles, with a small amount adhering to the inner wall surface of the gravity dust collector. The clean flue gas, after FeCl3 removal, is discharged from the outlet. This invention can meet the temperature control requirements of dust-laden flue gas under complex operating conditions and has the advantages of simple equipment, high efficiency, and stability. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a temperature-controlled gravity dust collector provided as an embodiment of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a temperature-controlled gravity dust collector, comprising:

[0026] The main structure of the gravity dust collector includes an inlet pipe section I, an ash collection tank section II, and an outlet pipe section III connected in sequence.

[0027] An air duct is provided outside the main structure of the gravity dust collector: a spiral air duct is provided outside the inlet pipe section I, the ash collection tank section II, and the outlet pipe section III. The lower end of the air duct is the air inlet, and the upper end of the air duct is the air outlet.

[0028] Figure 1 This is a schematic diagram of a temperature-controlled gravity dust collector according to an embodiment of the present invention. Wherein, 1 is section I of the inlet pipe, 1-1 is the air inlet of section I of the inlet pipe, 1-2 is the air outlet of section I of the inlet pipe, 2 is section II of the ash collection tank, 2-1 is the air inlet of section II of the ash collection tank, 2-2 is the air outlet of section II of the ash collection tank, 3 is section III of the outlet pipe, 3-1 is the air inlet of section III of the outlet pipe, and 3-2 is the air outlet of section III of the outlet pipe.

[0029] The present invention does not impose any special restrictions on the arrangement of the sequentially connected air inlet pipe section I, ash collection tank section II, and air outlet pipe section III. Any arrangement of the air inlet pipe section I, ash collection tank section II, and air outlet pipe section III that is well known to those skilled in the art can be used.

[0030] The intake pipe section I is vertically arranged, with a flue gas inlet at the top and a flue gas outlet at the bottom;

[0031] The ash collection tank section II is an inverted cone structure with a dust outlet at the bottom and a flue gas inlet and outlet at the top; the flue gas inlet of the ash collection tank section II is connected to the flue gas outlet of the air inlet pipe section I; the connection can be made by welding or threaded connection.

[0032] The exhaust pipe section III is vertically arranged, with a flue gas inlet at the bottom and a flue gas outlet at the top; the flue gas inlet of the exhaust pipe section III is connected to the flue gas outlet of the ash collection tank section II. The connection can be made by welding or threaded connection.

[0033] In some embodiments of the present invention, the intake pipe section I and the exhaust pipe section III can be cylindrical pipes or rectangular pipes.

[0034] In some embodiments of the present invention, an air intake pipe spiral rising air duct is provided outside the air intake pipe section I, the lower end of the air intake pipe spiral rising air duct is the air inlet, and the upper end of the air intake pipe spiral rising air duct is the air outlet.

[0035] In some embodiments of the present invention, a spiral rising air duct for the ash collection tank is provided outside the ash collection tank section II, with the lower end of the spiral rising air duct for the ash collection tank being an air inlet and the upper end of the spiral rising air duct for the ash collection tank being an air outlet.

[0036] In some embodiments of the present invention, a spiral rising air duct is provided outside the air outlet pipe section III, the lower end of the spiral rising air duct is an air inlet, and the upper end of the spiral rising air duct is an air outlet.

[0037] In this invention, the temperature and wind speed of the air inlet are adjusted as needed. Dust-laden hot flue gas is sent into the temperature-controlled gravity dust collector through the air inlet. After the FeCl3 gas in the flue gas condenses, it adheres to the surface of the dust particles, and a small amount adheres to the inner wall surface of the main structure of the gravity dust collector. The clean flue gas with FeCl3 removed is discharged from the air outlet.

[0038] The present invention does not impose any special restrictions on the size of the air duct, as long as the required temperature control can be achieved.

[0039] The present invention also provides a method for treating dust-laden flue gas, comprising the following steps:

[0040] The dust-laden flue gas is sequentially passed through the inlet pipe section I, the ash collection tank section II, and the outlet pipe section III of a temperature-controlled gravity dust collector to obtain the treated flue gas;

[0041] The temperature-controlled gravity dust collector is the same as the temperature-controlled gravity dust collector described above.

[0042] In some embodiments of the present invention, the dust-laden flue gas contains ≥90% TiCl4 by mass, 7%–9% FeCl3 by mass, and 1%–10% particulate matter by mass. The temperature of the dust-laden flue gas is 260–950°C, for example, 330–400°C or 260–310°C.

[0043] In some embodiments of the present invention, the cold air temperature at the air inlet of section I of the air inlet pipe is controlled to be room temperature, and the wind speed is 8-10 m / s; the cold air temperature at the air inlet of section II of the ash collection tank is 150-220°C, and the wind speed is 5-6 m / s; the cold air temperature at the air inlet of section III of the air outlet pipe is room temperature, and the wind speed is 6-8 m / s.

[0044] In some embodiments of the present invention, the cold air temperature at the air inlet of section I of the air inlet pipe is controlled to be 330-400°C, and the wind speed is 0-3m / s, and not 0; the cold air temperature at the air inlet of section II of the ash collection tank is controlled to be 330-400°C, and the wind speed is 0-3m / s, and not 0; the cold air temperature at the air inlet of section III of the air outlet pipe is controlled to be 330-400°C, and the wind speed is 0-3m / s, and not 0.

[0045] In some embodiments of the present invention, the cold air temperature at the air inlet of section I of the air inlet pipe is controlled to be 310-350°C and the wind speed is 5-10 m / s; the cold air temperature at the air inlet of section II of the ash collection tank is controlled to be 310-350°C and the wind speed is 5-10 m / s; and the cold air temperature at the air inlet of section III of the air outlet pipe is controlled to be 310-350°C and the wind speed is 5-10 m / s.

[0046] In some embodiments of the present invention, the inner wall temperature of the main structure of the gravity dust collector is controlled to be 220-380°C; for example, 220-300°C, 340-380°C, or 310-350°C.

[0047] The hot, dust-laden flue gas is treated by a temperature-controlled gravity dust collector, and the treated flue gas is cooled to room temperature, or the temperature of the treated flue gas is 330-400℃ or 290-330℃.

[0048] This invention achieves temperature control of a gravity dust collector by controlling the temperature and speed of the cooling or heating air at the air inlet. It has a simple structure and is easy to control.

[0049] In this invention, the temperature-controlled gravity dust collector has segmented temperature control in the inlet pipe section I, the ash collection tank section II, and the outlet pipe section III, which can achieve precise control of the wall temperature of the gravity dust collector to meet different working conditions such as flue gas temperature reduction, heat preservation, and heating.

[0050] When the temperature-controlled gravity dust collector is used for flue gas cooling, the wall temperature of the gravity dust collector is cleverly controlled to be higher than the boiling point of titanium tetrachloride and lower than the sublimation point of ferric chloride. After the FeCl3 gas in the dust-laden flue gas condenses, it adheres to the surface of the dust-laden flue gas and is discharged from the ash discharge port.

[0051] To further illustrate the present invention, the following detailed description of the temperature-controlled gravity dust collector and the method for treating dust-laden flue gas provided by the present invention is provided in conjunction with embodiments, but it should not be construed as a limitation on the scope of protection of the present invention.

[0052] Example 1

[0053] Based on the operating requirements, a temperature-controlled gravity dust collector is used for cooling dust-laden hot flue gas. Using slag from a certain manufacturer with a titanium carbide content of 14% as raw material, experiments were conducted in a fluidized bed reactor. The temperature of the dust-laden flue gas obtained from the furnace top after the reaction was 330–400℃. In the dust-laden flue gas, the mass content of TiCl4 was ≥90%, the mass content of FeCl3 was 7%–9%, ​​and the mass content of particulate matter was 1%–10%.

[0054] The dust-laden flue gas is sequentially passed through, as follows: Figure 1 The temperature-controlled gravity dust collector shown has an inlet pipe section I, an ash collection tank section II, and an outlet pipe section III, which together produce treated flue gas.

[0055] The inlet temperature of the air in section I of the inlet pipe is controlled at room temperature, and the air velocity is 8–10 m / s; the inlet temperature of the air in section II of the ash collection tank is controlled at 150–220℃, and the air velocity is 5–6 m / s; the inlet temperature of the air in section III of the outlet pipe is controlled at room temperature, and the air velocity is 6–8 m / s. The inner wall temperature of the temperature-controlled gravity dust collector is adjusted to 220–300℃. After the dust-laden flue gas is cooled to room temperature by the temperature-controlled gravity dust collector, the removal rate of FeCl3 in the flue gas reaches over 80%.

[0056] Example 2

[0057] Based on the operating requirements, the temperature-controlled gravity dust collector is used for heat preservation of dust-laden hot flue gas. Using slag from a certain manufacturer with a titanium carbide content of 14% by mass as raw material, experiments were conducted in a fluidized bed reactor. The temperature of the dust-laden flue gas obtained from the furnace top after the reaction was 330–400℃. In the dust-laden flue gas, the mass content of TiCl4 was ≥90%, the mass content of FeCl3 was 7%–9%, ​​and the mass content of particulate matter was 1%–10%.

[0058] The dust-laden flue gas is sequentially passed through, as follows: Figure 1 The temperature-controlled gravity dust collector shown has an inlet pipe section I, an ash collection tank section II, and an outlet pipe section III, which together produce treated flue gas.

[0059] The inlet temperature of the cold air in section I of the inlet pipe is controlled at 330–400℃, and the air velocity is 0–3 m / s, not zero; the inlet temperature of the cold air in section II of the ash collection tank is controlled at 330–400℃, and the air velocity is 0–3 m / s, not zero; the inlet temperature of the cold air in section III of the outlet pipe is controlled at 330–400℃, and the air velocity is 0–3 m / s, not zero. The inner wall temperature of the temperature-controlled gravity dust collector is adjusted to 340–380℃. After the dust-laden flue gas passes through the temperature-controlled gravity dust collector, the flue gas temperature remains at 330–400℃, no condensation occurs in the chlorides in the flue gas, the dust collected in the ash discharge tank does not clump, and the ash discharge channel is unobstructed.

[0060] Example 3

[0061] Based on the operating requirements, a temperature-controlled gravity dust collector is used for heating dust-laden hot flue gas. Using slag from a certain manufacturer with a titanium carbide content of 14% as raw material, experiments were conducted in a fluidized bed reactor. The temperature of the dust-laden flue gas obtained from the furnace top after the reaction was 260–310℃. In the dust-laden flue gas, the mass content of TiCl4 was ≥90%, the mass content of FeCl3 was 7%–9%, ​​and the mass content of particulate matter was 1%–10%.

[0062] The dust-laden flue gas is sequentially passed through, as follows: Figure 1 The temperature-controlled gravity dust collector shown has an inlet pipe section I, an ash collection tank section II, and an outlet pipe section III, which together produce treated flue gas.

[0063] The inlet temperature of the air in section I of the inlet pipe is controlled at 310–350℃, and the air velocity is 5–10 m / s; the inlet temperature of the air in section II of the ash collection tank is controlled at 310–350℃, and the air velocity is 5–10 m / s; the inlet temperature of the air in section III of the outlet pipe is controlled at 310–350℃, and the air velocity is 5–10 m / s. The inner wall temperature of the temperature-controlled gravity dust collector is adjusted to 310–350℃. After the dust-laden flue gas passes through the temperature-controlled gravity dust collector, the flue gas temperature is 290–330℃, reaching the predetermined temperature. No condensation occurs in the chlorides in the flue gas, the collected dust material in the ash discharge tank does not clump, and the ash discharge channel is unobstructed.

[0064] Comparative Example 1

[0065] Using a conventional gravity dust collector and slag with a titanium carbide content of 14% produced by a certain unit as raw material, an experiment was conducted in a fluidized bed reactor. The temperature of the dust-laden flue gas obtained from the furnace top after the reaction was 260–310℃. In the dust-laden flue gas, the mass content of TiCl4 was ≥90%, the mass content of FeCl3 was 7%–9%, ​​and the mass content of particulate matter was 1%–10%.

[0066] In the early stages of production, titanium tetrachloride in the flue gas condensed and liquefied in the gravity dust collector, causing severe caking of the collected dust inside the dust collector, making it difficult to remove the dust, and ultimately leading to production shutdown.

[0067] The descriptions of the above embodiments are merely illustrative of the methods and core ideas of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A temperature-controlled gravity dust collector, comprising: The main structure of the gravity dust collector includes an inlet pipe section I, an ash collection tank section II, and an outlet pipe section III connected in sequence. An air duct is provided outside the main structure of the gravity dust collector: an air inlet pipe spiral rising air duct is provided outside the air inlet pipe section I, the lower end of the air inlet pipe spiral rising air duct is the air inlet, and the upper end of the air inlet pipe spiral rising air duct is the air outlet. A spiral rising air duct for the ash collection tank is provided outside the ash collection tank section II. The lower end of the spiral rising air duct is the air inlet, and the upper end of the spiral rising air duct is the air outlet. A spiral rising air duct is provided outside the air outlet pipe section III. The lower end of the spiral rising air duct is the air inlet, and the upper end of the spiral rising air duct is the air outlet.

2. The temperature-controlled gravity dust collector according to claim 1, characterized in that, The intake pipe section I is vertically arranged, with a flue gas inlet at the top and a flue gas outlet at the bottom; The ash collection tank section II is an inverted cone structure with a dust outlet at the bottom and a flue gas inlet and outlet at the top; the flue gas inlet of the ash collection tank section II is connected to the flue gas outlet of the air inlet pipe section I. The exhaust pipe section III is vertically arranged, with a flue gas inlet at the bottom and a flue gas outlet at the top; the flue gas inlet of the exhaust pipe section III is connected to the flue gas outlet of the ash collection tank section II.

3. The temperature-controlled gravity dust collector according to claim 1, characterized in that, The intake pipe section I is a cylindrical pipe or a rectangular pipe; The exhaust pipe section III is a cylindrical pipe or a rectangular pipe.

4. A method for treating dust-laden flue gas, comprising the following steps: The dust-laden flue gas is sequentially passed through the inlet pipe section I, the ash collection tank section II, and the outlet pipe section III of a temperature-controlled gravity dust collector to obtain the treated flue gas; The temperature-controlled gravity dust collector is the temperature-controlled gravity dust collector as described in any one of claims 1 to 3.

5. The processing method according to claim 4, characterized in that, The dust-laden flue gas contains TiCl4 at a mass content of ≥90%, FeCl3 at a mass content of 7%~9%, and particulate matter at a mass content of 1%~10%.

6. The processing method according to claim 4, characterized in that, The temperature of the dust-laden flue gas is 260~950℃.

7. The processing method according to claim 4, characterized in that, When the temperature-controlled gravity dust collector is used for cooling dusty hot flue gas, the cold air temperature at the inlet of section I of the inlet pipe is controlled at room temperature, and the wind speed is 8~10 m / s; the cold air temperature at the inlet of section II of the ash collection tank is 150~220℃, and the wind speed is 5~6 m / s; the cold air temperature at the inlet of section III of the outlet pipe is controlled at room temperature, and the wind speed is 6~8 m / s. The temperature of the inner wall of the main structure of the gravity dust collector is controlled at 220~300℃.

8. The processing method according to claim 4, characterized in that, When the temperature-controlled gravity dust collector is used for heat preservation of dust-laden hot flue gas, the cold air temperature at the inlet of section I of the inlet pipe is controlled at 330~400℃, and the wind speed is 0~3 m / s, and not 0; the cold air temperature at the inlet of section II of the ash collection tank is controlled at 330~400℃, and the wind speed is 0~3 m / s, and not 0; the cold air temperature at the inlet of section III of the outlet pipe is controlled at 330~400℃, and the wind speed is 0~3 m / s, and not 0. The temperature of the inner wall of the main structure of the gravity dust collector is controlled at 340~380℃.

9. The processing method according to claim 4, characterized in that, When the temperature-controlled gravity dust collector is used for heating dust-laden hot flue gas, the cold air temperature at the inlet of section I of the inlet pipe is controlled at 310~350℃ and the wind speed at 5~10 m / s; the cold air temperature at the inlet of section II of the ash collection tank is controlled at 310~350℃ and the wind speed at 5~10 m / s; and the cold air temperature at the inlet of section III of the outlet pipe is controlled at 310~350℃ and the wind speed at 5~10 m / s. The temperature of the inner wall of the main structure of the gravity dust collector is controlled at 310~350℃.

Images