Anti-scar device and method for titanium dioxide chloride oxidation reactor and oxidation reactor

Abstract

The present invention relates to a scar prevention device for a titanium dioxide chloride oxidation reactor, comprising: a first air curtain area, on which a first inlet is arranged; a second air curtain area, which is separated from the first air curtain area and is adjacently located behind the first air curtain area, and a second inlet is arranged on the second air curtain area; and an air curtain area pipeline, which radially passes through the first air curtain area and the second air curtain area and extends, and the two ends of the air curtain area pipeline are respectively provided with a fluid inlet and a fluid outlet, and rows of spirally distributed air curtain holes are formed on the air curtain area pipeline along the radial direction. In addition, the present invention also relates to an oxidation reactor including the above-mentioned scar prevention device and a method for scar prevention of a titanium dioxide chloride oxidation reactor using the above-mentioned scar prevention device. The air curtain design of the present invention enables the wall surface to form a more uniform and dense gas protection layer, reduces the wall surface temperature in the high-temperature zone, prevents the adhesion of powder particles to the wall surface, and effectively reduces the probability of scar material deposition behind the titanium tetrachloride annular seam.

Description

Technical Field

[0001] The present invention relates to the field of oxidation reactors, in particular to an oxidation reactor for long-cycle operation of titanium dioxide chloride, and more specifically to an anti-scar device and method for a titanium dioxide chloride oxidation reactor and an oxidation reactor comprising the anti-scar device. Background Art

[0002] The TiCl4 gas phase oxidation reaction is completed in a very short time and releases a large amount of heat instantly. During the reaction process, a titanium dioxide solid phase product with extremely small and uniform particle size is generated. The solid phase product is very easy to deposit on the surface of the reactor, grow and develop into a scar layer. There are various forms of scar removal and scar prevention technologies for titanium tetrachloride gas phase oxidation reactors at home and abroad. For example, USP3284159 and 200810112178.X use porous walls to form an air curtain protective layer to prevent the adhesion of titanium dioxide particles on the reactor wall. There is a certain distance between the holes of the porous structure set on the pipeline. If the spacing between the holes is too large, the gas protection effect between the holes is poor. If the spacing is too small, the air curtain structure is prone to instability and damage. CN00243616.7 uses artificial titanium dioxide scar material to be sprayed from the furnace head spray gun to weaken the scar near the titanium tetrachloride nozzle, but the amount of scar material sprayed is large, which is easy to cause excessive heat loss, reduce the material mixing temperature, and affect product quality.

[0003] After titanium tetrachloride is mixed with oxygen, a high concentration area of ​​titanium dioxide will be formed on the wall after a certain distance. At the same time, due to the large amount of reaction heat, the wall temperature here is high, which accelerates the deposition of titanium dioxide particles on the wall. After the titanium dioxide is deposited, the thermal conductivity of the pipeline will be reduced, and the high-temperature wall temperature will be further increased, worsening the deposition and sintering of titanium dioxide. Therefore, if a reasonable air curtain area is set in the strong exothermic reaction area, the high temperature of the wall caused by the strong exothermic reaction can be quickly cooled, and the deposition and sintering of the newly formed titanium dioxide particles can be weakened. At the same time, the gas-solid flow field can be optimized, the average residence time of the solid particles can be uniform, the product particle size distribution range can be narrowed, and the product quality can be improved. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention optimizes the structure of the titanium dioxide chloride oxidation reactor, sets a porous and multi-stage expanded air curtain in the strong exothermic reaction zone, extends the operation cycle of the oxidation reactor, and reduces the frequency of production stoppages caused by scarring. At the same time, the present invention optimizes the flow field in the reaction zone, evens out the main fluid velocity, and reduces the product particle size distribution range.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] According to one aspect of the present invention, there is provided a scar prevention device for a titanium dioxide chloride oxidation reactor, comprising:

[0007] A first air curtain area, wherein a first inlet is provided on the first air curtain area;

[0008] a second air curtain area, which is spaced apart from the first air curtain area and is adjacently located behind the first air curtain area, and a second inlet is disposed on the second air curtain area; and

[0009] The air curtain area pipeline axially passes through the first air curtain area and the second air curtain area and extends, a fluid inlet and a fluid outlet are respectively arranged at both ends of the air curtain area pipeline, and rows of spirally distributed air curtain holes are formed on the air curtain area pipeline along the radial direction.

[0010] In one embodiment of the present invention, the air curtain area pipe is in a trumpet shape, and the expansion angle is 3°-10°.

[0011] In one embodiment of the present invention, the air curtain holes are tangentially air-inlet.

[0012] In one embodiment of the present invention, the spacing between each row of curtain holes is equal.

[0013] In one embodiment of the present invention, the number of rows of air curtain holes on the air curtain zone pipeline in the first air curtain zone is 1-2 rows, the diameter is 1.5-3 mm, and the opening rate is 0.2%-1%.

[0014] In one embodiment of the present invention, the number of rows of air curtain holes on the air curtain zone pipeline in the second air curtain zone is 6-15 rows, the diameter is 2-4 mm, and the opening rate is 0.2%-2%.

[0015] In one embodiment of the present invention, the direction of the first inlet is tangential to the diameter of the tube furnace; the direction of the second inlet is tangential to the circumference of the tube furnace and forms an angle of 30°-80° axially.

[0016] In one embodiment of the present invention, nitrogen or chlorine is introduced into the first inlet and the second inlet simultaneously.

[0017] According to another aspect of the present invention, there is provided a titanium dioxide chloride oxidation reactor, comprising the titanium dioxide chloride oxidation reactor anti-scar device as described above.

[0018] According to another aspect of the present invention, a method for preventing scars in a titanium dioxide chloride oxidation reactor is provided. The method uses the titanium dioxide chloride oxidation reactor prevention device as described above, wherein nitrogen or chlorine is simultaneously introduced into the first inlet and the second inlet of the scar prevention device, the air intake speed of the air curtain holes in the first air curtain area is controlled to be 40-80 m / s, and the air intake speed of the air curtain holes in the second air curtain area is controlled to be 20-60 m / s, and a mixture of oxygen and titanium tetrachloride is introduced into the air curtain area pipeline through the fluid inlet of the air curtain area pipeline for oxidation reaction.

[0019] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0020] The air curtain design of the present invention enables the wall surface to form a more uniform and dense gas protection layer, reduces the wall surface temperature in the high-temperature zone, prevents the powder particles from adhering to the wall surface, effectively reduces the probability of scar material deposition behind the titanium tetrachloride annular seam, and at the same time ensures that the axial velocity of the fluid remains unchanged after the gas is added in each air curtain area, ensures the uniformity and stability of the flow field, reduces the intensification of particle collision caused by the increase in the turbulence intensity of the flow field, and narrows the product particle size distribution range. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The structural schematic diagram of the anti-scar device of the titanium dioxide chloride oxidation reactor provided by the present invention is shown;

[0022] Figure 2 Shows Figure 1 Sectional view at AA in the middle;

[0023] Figure 3 The schematic diagram of the structure of the air curtain area pipeline provided by the present invention is shown.

[0024] Reference numerals list

[0025] 1 first air curtain area, 2 second air curtain area, 3 first inlet, 4 second inlet, 5 air curtain area pipeline, 51 air curtain small hole, 6 fluid inlet, 7 fluid outlet. DETAILED DESCRIPTION

[0026] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present invention, it is easy for those skilled in the art to appreciate that multiple modifications are feasible without actually departing from the teaching of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other replacements, modifications, changes and deletions may be made to the design, operating conditions and parameters of the following exemplary embodiments.

[0027] like Figure 1-3 The present invention discloses a scar prevention device for a titanium dioxide chloride oxidation reactor, comprising: a first air curtain area 1, a second air curtain area 2 and an air curtain area pipeline 5, wherein a first inlet 3 is arranged on the first air curtain area 1, the second air curtain area 2 is separated from the first air curtain area 1 and is adjacent to the rear of the first air curtain area 1, a second inlet 4 is arranged on the second air curtain area 2, the air curtain area pipeline 5 axially extends through the first air curtain area 1 and the second air curtain area 2, a fluid inlet 6 and a fluid outlet 7 are respectively arranged at both ends of the air curtain area pipeline 5, and rows of spirally distributed air curtain holes 51 are formed on the air curtain area pipeline 5 along the radial direction.

[0028] Through the present invention, the air curtain design of the present invention enables the wall surface to form a more uniform and dense gas protection layer, reduces the wall surface temperature in the high-temperature zone, prevents the powder particles from adhering to the wall surface, effectively reduces the probability of scar material deposition behind the titanium tetrachloride annular seam, and at the same time ensures that the axial velocity of the fluid remains unchanged after the gas is added in each air curtain area, ensures the uniformity and stability of the flow field, reduces the intensification of particle collision caused by the increase in the turbulence intensity of the flow field, and narrows the product particle size distribution range.

[0029] In the above structure, if Figure 1 and 3 As shown, the air curtain area duct 5 is in a trumpet shape, and the expansion angle is 3°-10°, preferably 5°.

[0030] In the above structure, if Figure 2-3 As shown, the air curtain holes 51 are tangentially air-intake, and the air curtain holes 51 are spirally distributed on the air curtain area pipeline 5, which further makes the air curtain layer uniform and prevents the formation of a channel without air curtain.

[0031] In the above structure, if Figure 1 and 3 As shown, the spacing between each row of curtain holes 51 is equal.

[0032] In the above structure, if Figure 1 As shown, the number of rows of air curtain holes 51 on the air curtain zone pipe 5 in the first air curtain zone 1 is 1-2 rows, the diameter is 1.5-3 mm, and the opening rate is 0.2%-1%. The number of rows of air curtain holes 51 on the air curtain zone pipe 5 in the second air curtain zone 2 is 6-15 rows, the diameter is 2-4 mm, and the opening rate is 0.2%-2%. The air intake speeds of the air curtain holes in the first air curtain zone 1 and the second air curtain zone 2 are different to ensure the uniformity of the air curtain layer, which not only quickly reduces the wall temperature and prevents titanium dioxide particles from adhering to the wall, but also uniformizes the flow field and reduces the disturbance of the mainstream field caused by gas.

[0033] In the above structure, if Figure 1 As shown, the direction of the first inlet 3 is tangential to the diameter of the tube furnace to ensure that it is consistent with the direction of the velocity streamline of the gas curtain hole; the direction of the second inlet 4 is tangential to the circumference of the tube furnace and axially forms an angle of 30°-80°, preferably 45°, so that the initial direction of the gas points to the front end of the expansion, further uniforming the distribution of the gas in the second gas curtain area 2.

[0034] In the above structure, if Figure 1 As shown, nitrogen or chlorine gas is introduced into the first inlet 3 and the second inlet 4 simultaneously.

[0035] In addition, the present invention also provides a titanium dioxide chloride oxidation reactor, comprising the titanium dioxide chloride oxidation reactor anti-scar device as described above.

[0036] In addition, the present invention also provides a method for preventing scars in a titanium dioxide chloride oxidation reactor, which uses the titanium dioxide chloride oxidation reactor prevention device as described above, wherein nitrogen or chlorine is simultaneously introduced into the first inlet and the second inlet of the scar prevention device, the air intake speed of the air curtain holes in the first air curtain area is controlled to be 40-80m / s, and the air intake speed of the air curtain holes in the second air curtain area is controlled to be 20-60m / s, and a mixture of oxygen and titanium tetrachloride is introduced into the air curtain area pipeline through the fluid inlet of the air curtain area pipeline for oxidation reaction.

[0037] In the above method, the air intake speed of the air curtain holes in the first air curtain area is 40m / s to 80m / s, and the air intake speed of the air curtain holes in the second air curtain area is 20-60m / s. The second air curtain area is separated from the first air curtain area. At the same time, the air intake speed of the air curtain holes in the first air curtain area is relatively large, which can ensure that the gas initially forms an air curtain protection area in the first air curtain area. The air intake speed of the air curtain holes in the second air curtain area is low, which will not cause too much gas to enter the mainstream area, thereby reducing its influence on the movement of titanium dioxide particles in the main fluid.

[0038] More specifically, the specific embodiments of the present invention are as follows:

[0039] like Figure 1-3 As shown: the front end diameter of the expanded opening of the air curtain zone pipeline 5 of the titanium dioxide chloride oxidation reactor is 180 mm, the expanded opening angle is 5°, the total expanded opening length of the air curtain zone pipeline 5 is 300 mm, and the length of the first air curtain zone 1 is 25 mm, the number of rows of air curtain holes 51 is 1, the diameter is 1.5 mm, the porosity is 0.4%, the air intake speed of the air curtain holes 51 is 65 m / s, the length of the second air curtain area 2 is 275 mm, the number of rows of air curtain holes 51 is 10, the diameter is 2.5 mm, the porosity is 0.8%, the air intake speed of the air curtain holes 51 is 45 m / s, the air curtain holes 51 are all tangentially inlet, and the air curtain holes 51 are spirally distributed on the air curtain area pipe 5 or the trumpet-shaped expansion pipe; the direction of the first inlet 3 is tangential to the diameter of the tubular furnace to ensure that it is consistent with the direction of the velocity streamline of the air curtain holes 51; the direction of the second inlet 2 is tangential to the circumference of the tubular furnace, and at the same time, the axial direction forms an angle of 45° to drive the gas to flow to the front end of the second air curtain area 2. With this design structure, the gas in each gas curtain area forms a uniform gas isolation layer on the wall, which reduces the wall temperature and prevents the adhesion of titanium dioxide particles to the wall; after the planned shutdown of the oxidation reactor, there is no obvious scarring on the wall of the furnace.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced by equivalents without departing from the spirit and scope of the present invention, it should be included in the protection scope of the claims of the present invention.

Claims

1. A scar prevention device for a titanium dioxide chloride oxidation reactor, characterized in that: include: A first air curtain area, wherein a first inlet is provided on the first air curtain area; a second air curtain area, which is spaced apart from the first air curtain area and is adjacently located behind the first air curtain area, and a second inlet is disposed on the second air curtain area; and An air curtain area pipeline, wherein the air curtain area pipeline axially extends through the first air curtain area and the second air curtain area, a fluid inlet is provided at one end of the air curtain area pipeline, and a fluid outlet is provided at the other end, the diameter of the fluid outlet is larger than the diameter of the fluid inlet, and rows of spirally distributed air curtain holes are formed on the air curtain area pipeline along the radial direction, the air curtain holes are tangentially air-intake, and the air curtain area pipeline is in a trumpet shape, and the expansion angle is 3°-10°; The direction of the first inlet is tangential to the diameter of the tube furnace so as to be consistent with the direction of the velocity streamline of the small holes of the gas curtain, and the direction of the second inlet is tangential to the circumference of the tube furnace and axially at an angle of 30°-80° so that the initial direction of the gas points to the front end of the expansion to uniformly distribute the gas in the second gas curtain area, wherein the front end of the expansion is the part with a smaller expansion diameter.

2. The anti-scar device for the titanium dioxide chloride oxidation reactor according to claim 1, characterized in that: The spacing between the holes in each row of curtains is equal.

3. The anti-scar device for the titanium dioxide chloride oxidation reactor according to claim 2, characterized in that: The number of rows of the air curtain holes on the air curtain zone pipeline in the first air curtain zone is 1-2 rows, the diameter is 1.5-3 mm, and the opening rate is 0.2%-1%.

4. The anti-scar device for the titanium dioxide chloride oxidation reactor according to claim 3, characterized in that: The number of rows of the air curtain holes on the air curtain zone pipeline in the second air curtain zone is 6-15 rows, the diameter is 2-4 mm, and the opening rate is 0.2%-2%.

5. The anti-scar device for the titanium dioxide chloride oxidation reactor according to claim 1, characterized in that: Nitrogen or chlorine is introduced into the first inlet and the second inlet simultaneously.

6. A titanium dioxide oxidation reactor, characterized in that: It comprises a scar prevention device for a titanium dioxide chloride oxidation reactor as described in any one of claims 1 to 5.

7. A method for preventing scars in a titanium dioxide chloride oxidation reactor, characterized in that: The method uses a scar prevention device for a titanium dioxide chloride oxidation reactor as described in any one of claims 1 to 5, wherein nitrogen or chlorine is introduced into the first inlet and the second inlet of the scar prevention device at the same time, the air intake speed of the air curtain holes in the first air curtain area is controlled to be 40-80 m / s, and the air intake speed of the air curtain holes in the second air curtain area is controlled to be 20-60 m / s, and a mixture of oxygen and titanium tetrachloride is introduced into the air curtain area pipeline through the fluid inlet of the air curtain area pipeline for oxidation reaction.

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