阅读说明：本技术 一种氯化钛白氧化反应器的防疤装置及氧化反应器 (Scar-proof device of titanium white chloride oxidation reactor and oxidation reactor ) 是由 李冬勤 杜明 陆平 周艾然 于 2021-11-15 设计创作，主要内容包括：本公开提供一种氯化钛白氧化反应器的防疤装置,包含：环形的外壁,外壁具有沿切向设置的气幕入口；以及环形的内壁,内壁同轴地套设于外壁内并具有多孔结构,其中内壁与外壁之间限定气幕区以容纳气幕气体；其中,气幕气体由外壁的气幕入口螺旋进入气幕区,并经内壁排出。该防疤装置中,气幕气体由切向气幕入口螺旋进入气幕区并在启幕区内均匀分布,经多孔结构的内壁均匀喷入反应器内形成气体保护层,有效降低了侧壁内表面温度并阻止钛白颗粒的附着。本公开同时提出了一种包含该防疤装置的氯化钛白氧化反应器、以及使用该氯化钛白氧化反应器制备钛白粉的方法。(The present disclosure provides a scar-preventing device for a titanium white chloride oxidation reactor, comprising: an annular outer wall having a tangentially disposed air curtain inlet; and an annular inner wall coaxially nested within the outer wall and having a porous structure, wherein a gas curtain region is defined between the inner wall and the outer wall to contain a gas curtain gas; wherein, the gas curtain gas enters the gas curtain area from the gas curtain inlet of the outer wall in a spiral way and is discharged through the inner wall. In the scar-preventing device, the gas curtain enters the gas curtain area from the tangential gas curtain inlet in a spiral way and is uniformly distributed in the curtain opening area, and the gas is uniformly sprayed into the reactor through the inner wall of the porous structure to form a gas protective layer, so that the temperature of the inner surface of the side wall is effectively reduced, and the attachment of titanium dioxide particles is prevented. The disclosure also provides a titanium chloride white oxidation reactor containing the scar-preventing device and a method for preparing titanium dioxide by using the titanium chloride white oxidation reactor.)

1. A scar-proof device for a titanium white chloride oxidation reactor is characterized by comprising:

an annular outer wall having a tangentially disposed air curtain inlet; and

an annular inner wall coaxially nested within the outer wall and having a porous structure, wherein the inner wall and the outer wall define a gas curtain region therebetween to contain a gas curtain gas;

wherein, the gas curtain gas is spirally entered into the gas curtain area from the gas curtain inlet of the outer wall and is discharged from the inner wall.

2. The device of claim 1, further comprising at least one partition dividing the air curtain zone into a plurality of air curtain sections in an axial direction.

3. The anti-scarring device of claim 2, wherein the spacing between the partitions increases progressively in the axial direction.

4. The anti-scarring device of claim 3, wherein each air curtain section corresponds to an air curtain inlet for separate air supply.

5. The anti-scarring device according to claim 1, wherein the inner wall is made of porous ceramic having pores with a diameter of 0.01mm to 2mm and a porosity of 40% to 70%.

6. A titanium chloride dioxide oxidation reactor comprising the scar prevention device as defined in any one of claims 1 to 5, wherein,

the reactor comprises a side wall having an annular cross-section, the side wall defining an axially extending oxygen channel, TiCl being circumferentially disposed along the side wall₄A channel;

the scar-proof device is coaxially embedded in the side wall of the reactor, and the inner surface of the inner wall of the scar-proof device is flush with the inner surface of the side wall;

wherein oxygen flows along the oxygen channel, passing through the TiCl₄The channel and TiCl₄After merging, a main air flow is formed, which then flows through the anti-scarring device.

7. The titanium white chloride oxidation reactor as set forth in claim 6, wherein the scar prevention device is disposed at a distance from the TiCl in an axial direction₄A reaction strong heat release area at the position of 30 mm-150 mm of the channel.

8. The titanium white chloride oxidation reactor according to claim 7, wherein the length of the gas curtain region of the scar prevention device in the axial direction is 20mm to 300 mm.

9. A process for producing titanium dioxide, characterized in that it uses the titanium chloride dioxide oxidation reactor as claimed in any one of claims 6 to 8, wherein the spacing between the partitions of the anti-scarring device increases in the direction of the main gas flow, and the flow rate of the gas curtain gas entering the plurality of gas curtain zones decreases in the direction of the main gas flow.

10. The method of claim 9, wherein the gas curtain gas to primary gas flow momentum ratio is from 1:100 to 1: 400.

Technical Field

The disclosure belongs to the technical field of titanium dioxide preparation by a chlorination method, and particularly relates to a scar-preventing device of a titanium chloride white oxidation reactor, the titanium chloride white oxidation reactor comprising the scar-preventing device, and a method for preparing titanium dioxide by using the titanium chloride white oxidation reactor.

Background

Titanium dioxide is widely applied to the industrial fields of paint, plastics, chemical fibers and the like as an important chemical product. At present, titanium dioxide is mainly prepared by a chlorination method, and the oxidation of titanium dioxide chloride is a key step in the method. TiCl (titanium dioxide)₄The gas phase oxidation reaction can be completed in a very short time and instantaneously releases a large amount of heat. In the reaction process, a titanium dioxide solid phase product with extremely small and uniform granularity is generated, and the solid phase product is easy to deposit, grow and develop into a scar layer on the surface of the reactor. In the prior art, a scar layer is generally removed by a mechanical scraping method and a sand blasting method, or a scar layer is prevented by an air film protection method and a porous wall method. For example, USP3284159, 200810112178.X uses a porous wall to form a gas curtain protection layer to prevent the adhesion of titanium dioxide particles on the reactor wall, and the porous structure provided on the pipe has a certain distance between the holes, and if the distance between the holes is too large, the gas protection effect between the holes is poor, and if the distance between the holes is too small, the gas curtain structure is easily unstable and damaged; CN00243616.7 utilizes artificial titanium white scar material to spray from the furnace end spray gun, and reduces the scar near the titanium tetrachloride spray nozzle; however, the amount of the sprayed scar materials is large, excessive heat loss is easily caused, the material mixing temperature is reduced, and the product quality is influenced.

Therefore, the problem to be solved in the technical field of preparing titanium dioxide by a chlorination method is solved by avoiding the scab of the reactor during the oxidation reaction of titanium dioxide chloride.

BRIEF SUMMARY OF THE PRESENT DISCLOSURE

In order to solve the prior technical problem, the disclosure provides a scar-preventing device of a titanium white chloride oxidation reactor, gas curtain gas enters a gas curtain area from a tangential gas curtain inlet in a spiral manner and is uniformly distributed in the curtain opening area, and the gas curtain gas is uniformly sprayed into the reactor through the inner wall of a porous structure to form a gas protection layer, so that the temperature of the inner surface of the side wall is effectively reduced, and titanium white particles are prevented from being attached. The disclosure also provides a titanium chloride white oxidation reactor containing the scar-preventing device and a method for preparing titanium dioxide by using the titanium chloride white oxidation reactor.

According to the present disclosure, there is provided a scar prevention device for a titanium white chloride oxidation reactor, comprising:

an annular outer wall having a tangentially disposed air curtain inlet; and

an annular inner wall coaxially nested within the outer wall and having a porous structure, wherein a gas curtain region is defined between the inner wall and the outer wall to contain a gas curtain gas;

wherein, the gas curtain gas enters the gas curtain area from the gas curtain inlet of the outer wall in a spiral way and is discharged through the inner wall.

According to an embodiment of the present disclosure, the anti-scarring device further comprises at least one partition plate, and the partition plate divides the air curtain region into a plurality of air curtain sections along the axial direction.

According to one embodiment of the present disclosure, the spacing between the partitions gradually increases in the axial direction.

According to one embodiment of the present disclosure, each air curtain section corresponds to an air curtain inlet for separate air supply.

According to one embodiment of the present disclosure, the inner wall is made of porous ceramic, the pore diameter of the pores in the porous ceramic is 0.01 mm-2 mm, and the porosity is 40% -70%.

According to the present disclosure, there is provided a titanium white chloride oxidation reactor comprising the above scar prevention device, wherein,

the reactor comprises a side wall having an annular cross-section, the side wall defining an axially extending oxygen channel, TiCl being circumferentially disposed along the side wall₄A channel;

the scar-proof device is coaxially embedded in the side wall of the reactor, and the inner surface of the inner wall of the scar-proof device is flush with the inner surface of the side wall;

wherein oxygen flows along the oxygen channel past the TiCl₄The channel and TiCl₄The confluence forms a primary air flow which then flows through the anti-scarring device.

According to one embodiment of the present disclosure, the anti-scarring means is arranged at a distance TiCl in the axial direction₄A reaction strong heat release area at the position of 30 mm-150 mm of the channel.

According to one embodiment of the present disclosure, the length of the air curtain region of the scar prevention device along the axial direction is 20mm to 300 mm.

According to the present disclosure, a method for preparing titanium dioxide is provided, which uses the titanium chloride white oxidation reactor, wherein the distance between the plurality of baffles of the scar prevention device is gradually increased along the flow direction of the main air flow, and the flow velocity of the air curtain gas entering the plurality of air curtain zones is gradually decreased along the flow direction of the main air flow.

According to one embodiment of the present disclosure, the momentum ratio of the gas curtain gas to the main gas flow is 1:100 to 1: 400.

Due to the adoption of the technical scheme, compared with the prior art, the method has the following advantages:

1. according to the scar-preventing device disclosed by the invention, the air curtain inlet is tangentially arranged, air curtain gas can enter the air curtain area in a spiral shape, so that the phenomenon of uneven gas pressure in the air curtain area is effectively avoided, the air curtain gas is uniformly sprayed into the reactor through the inner wall of the porous structure, a more uniform and compact gas protection layer is further formed on the inner surface of the side wall of the reactor, and the attachment and scar formation of titanium dioxide particles on the wall surface are prevented;

2. the scar preventing device comprises a plurality of independent air curtain partitions for air inlet, and is convenient for controlling and adjusting the gas protecting layers in different states;

3. according to the titanium white chloride oxidation reactor disclosed by the invention, the scar-preventing device is arranged on TiCl₄The reaction strong heat release area near the channel effectively improves the scabbing phenomenon of the inner surface of the side wall of the reactor;

4. according to the method for preparing titanium dioxide, the distribution and momentum of gas curtain gas are reasonably set, so that the gas curtain gas can form an effective barrier on the inner surface of the side wall of the reactor.

Drawings

FIG. 1 is a cross-sectional view of a titanium dioxide chloride oxidation reactor including an anti-scarring device according to the present disclosure;

FIG. 2 is a sectional view of the reactor shown in FIG. 1 taken along the direction A-A.

In the drawings

1 outer wall, 11 air curtainPort, 2 inner wall, 3 gas curtain zone, 31 first gas curtain zone, 32 second gas curtain zone, 3 nth gas curtain zone, 4 partition plate, 5 side wall, 6 oxygen channel, 7TiCl₄A channel.

Detailed Description

In order to make the objects, technical solutions and advantages of the present disclosure more apparent, the present disclosure is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the disclosure and are not intended to limit the disclosure.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein in the description is for the purpose of describing particular embodiments only and is not intended to limit the disclosure, e.g., the terms "length," "width," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," "outer," "lateral," "longitudinal," "vertical," "axial," "radial," etc., indicate an orientation or position based on that shown in the drawings, are for convenience of description only and are not to be construed as limiting the present disclosure.

FIG. 1 illustrates a cross-sectional view of a titanium oxychloride oxidation reactor containing one embodiment of a scar prevention device according to the present disclosure; FIG. 2 shows a cross-sectional view of the reactor of FIG. 1 along the A-A direction. The reactor may be, for example, a tube furnace or other form of reaction apparatus, generally comprising a side wall 5 having an annular cross-section. In examples of the present disclosure, the sidewall 5 may define an axially extending oxygen channel 6, oxygen flowing in the direction of the axial arrow; TiCl (titanium dioxide)₄The channels 7 may be arranged circumferentially along the side wall 5 to form circumferential seams, TiCl₄Flows into the oxygen channel 6 along the direction of the radial arrow to be merged with oxygen to form a main gas flow and reacts in the subsequent flow process to generate titanium dioxide. The scar preventing device is arranged on TiCl in the axial direction₄The downstream area of the channel 7, through which the main air flow is formed, prevents the reaction-forming titanium dioxide from scabbing. In the oxidation process of titanium white chloride，TiCl₄After mixing with oxygen and passing a certain distance, a titanium dioxide high-concentration area is formed on the inner surface of the side wall 5, and meanwhile, the surface temperature of the area is high due to more reaction heat, so that the deposition of titanium dioxide particles on the surface is accelerated, the heat conduction capability of a pipeline is reduced after the titanium dioxide is deposited, the temperature of a high-temperature wall surface is further increased, the deposition and sintering of the titanium dioxide are deteriorated, and therefore, a scar-preventing device is arranged in a strong reaction heat release area, and the deposition and sintering of the titanium dioxide can be more effectively reduced. In the examples of the present disclosure, the anti-scarring means is preferably arranged at a distance TiCl in the axial direction₄The length of the air curtain region 3 of the anti-scar device along the axial direction at the position of about 30 mm-150 mm of the channel 7 can be 20 mm-300 mm. The position and the size of the scar preventing device can be adjusted by the person skilled in the art according to the actual working condition.

The anti-scarring device according to the present disclosure generally comprises an annular outer wall 1, an annular inner wall 2, the annular inner wall 2 and a gas curtain region 3 defined between the inner wall 2 and the outer wall 1 for containing a gas curtain gas. Wherein, outer wall 1 has the air curtain entry 11 along the tangential setting, and the extending direction of air curtain entry 11 is perpendicular to the diametral of the annular cross-section of outer wall 1 promptly, can make air curtain gas be the heliciform and get into air curtain district 3 and evenly distributed from this, avoids the uneven phenomenon of the inside gas pressure in air curtain district 3. The inner wall 2 is coaxially sleeved in the outer wall 1 and has a porous structure, and the gas curtain gas in the gas curtain area 3 can be discharged to the outside of the scar preventing device, namely the oxidation channel of the reactor through the inner wall 2. Because the pressure distribution of the gas at each position in the gas curtain area 3 is uniform, the gas curtain gas can be uniformly sprayed into the reactor, and a uniform and compact gas protective layer is formed on the inner surface of the side wall 5 of the reactor, so that the temperature of the side wall 5 can be reduced, and the titanium dioxide particles can be effectively prevented from being adhered to and scabbed on the wall surface.

In the disclosed example, the side wall 5 of the reactor has radially extending grooves, the anti-scarring means being embedded coaxially within the side wall 5 of the reactor. Wherein the inner surface of the inner wall 2 of the anti-scarring device is flush with the inner surface of the side wall 5 of the reactor to form part of the oxygen channel 6; a part of the side wall 5 of the reactor forming the trench defines the gas curtain zone 3 together with the inner wall 2 as the outer wall 1 of the anti-scarring means. Alternatively, the outer wall 1 of the anti-scarring device may also be formed separately from the side wall 5 of the reactor and mounted in place in the reactor in a subsequent process.

The anti-scarring device may further comprise at least one partition 4, and the partition 4 may divide the air curtain region 3 into a first air curtain partition 31, a second air curtain partition 32 … … and an nth air curtain partition 3n in the axial direction. Preferably, the number of the partition plates 4 may be 1 to 8. The partitions 4 may have different distances in the axial direction, for example arranged to gradually increase or decrease in the axial direction. Each of the curtain sections 31, 32 … … 3n may correspond to a curtain inlet 11 for separately supplying gas to control the flow rate of curtain gas into each of the curtain sections 31, 32 … … 3n independently of each other. The inner wall 2 may be made of a porous ceramic, such as alumina, in which the pores have a diameter of preferably 0.01mm to 2mm and a porosity of preferably 40% to 70%, to ensure that a gas curtain gas forms a fine and dense bubble group when passing through the inner wall 2.

By adopting the reactor for preparing titanium dioxide according to the disclosure, the distance between the plurality of partition plates 4 of the scar preventing device can be gradually increased along the flow direction of the main air flow, and the flow velocity of the air curtain gas entering the plurality of air curtain partitions 31 and 32 … … 3n is gradually decreased along the flow direction of the main air flow. Wherein, the momentum ratio of the gas curtain gas to the main gas flow is 1: 100-1: 400, so as to ensure that the gas curtain gas forms an effective barrier effect on the inner surface of the side wall 5.

The following are specific examples of the continuous casting production method according to the present disclosure.

Example 1

In this embodiment, the inner wall of the scar preventing device is made of 99% alumina ceramic, the aperture of the small hole is 1mm, and the porosity is 50%; oxygen passage diameter 55mm in reactor, scar-proof device and TiCl₄The channel distance was 50mm and the length of the air curtain region was 100 mm. The control parameters in the reaction process are as follows:

mean gas velocity of main gas flow	30m/s
		Length of first air curtain partition	10mm
First air curtain partition air speed	0.5m/s
		Second air curtain partition length	20mm
Second air curtain partition air speed	0.4m/s
		Length of third air curtain partition	30mm
Third air curtain partition air speed	0.3m/s
		Fourth air curtain partition length	40mm
Fourth air curtain partition air speed	0.2m/s

The first air curtain partition, the second air curtain partition, the third air curtain partition and the fourth air curtain partition are sequentially arranged along the flow direction of the main air flow. The oxidation reaction is carried out under the process parameters, and the gas in the gas curtain area forms a uniform gas isolation layer on the wall surface, so that the temperature of the wall surface is reduced, and the adhesion of titanium dioxide particles on the wall surface is prevented; after the oxidation reactor is shut down in a planned way, no obvious scab is formed on the inner wall surface of the furnace.

Example 2

In this embodiment, the inner wall of the scar preventing device is made of 99% alumina ceramic, the aperture of the small hole is 2mm, and the porosity is 70%; oxygen passage diameter 55mm in reactor, scar-proof device and TiCl₄The channel distance was 100mm and the length of the air curtain region was 200 mm. The control parameters in the reaction process are as follows:

the first air curtain partition, the second air curtain partition, the third air curtain partition and the fourth air curtain partition are sequentially arranged along the flow direction of the main air flow. The oxidation reaction is carried out under the process parameters, and the gas in the gas curtain area forms a uniform gas isolation layer on the wall surface, so that the temperature of the wall surface is reduced, and the adhesion of titanium dioxide particles on the wall surface is prevented; after the oxidation reactor is shut down in a planned way, no obvious scab is formed on the inner wall surface of the furnace.

Example 3

In this embodiment, the inner wall of the scar-preventing device is made of 99% alumina ceramic, the pore diameter of the small pores is 0.01mm, and the porosity is 40%; oxygen passage diameter 55mm in reactor, scar-proof device and TiCl₄The channel distance was 150mm and the length of the air curtain zone was 300 mm. The control parameters in the reaction process are as follows:

the first air curtain partition, the second air curtain partition, the third air curtain partition, the fourth air curtain partition, the fifth air curtain partition, the sixth air curtain partition, the seventh air curtain partition and the eighth air curtain partition are sequentially arranged along the flow direction of the main air flow. The oxidation reaction is carried out under the process parameters, and the gas in the gas curtain area forms a uniform gas isolation layer on the wall surface, so that the temperature of the wall surface is reduced, and the adhesion of titanium dioxide particles on the wall surface is prevented; after the oxidation reactor is shut down in a planned way, no obvious scab is formed on the inner wall surface of the furnace.

Example 4

In the embodiment, the inner wall of the scar-proof device is made of 99% alumina ceramic, the aperture of the small hole is 0.5mm, and the porosity is 60%; oxygen passage diameter 55mm in reactor, scar-proof device and TiCl₄The channel distance was 30mm and the length of the air curtain region was 20 mm. The control parameters in the reaction process are as follows:

mean gas velocity of main gas flow	30m/s
		Length of first air curtain partition	5mm
First air curtain partition air speed	0.9m/s
		Second air curtain partition length	15mm
Second air curtain partition air speed	0.3m/s

Wherein the first air curtain partition and the second air curtain partition are arranged in sequence along the flow direction of the main air flow. The oxidation reaction is carried out under the process parameters, and the gas in the gas curtain area forms a uniform gas isolation layer on the wall surface, so that the temperature of the wall surface is reduced, and the adhesion of titanium dioxide particles on the wall surface is prevented; after the oxidation reactor is shut down in a planned way, no obvious scab is formed on the inner wall surface of the furnace.

The above embodiments illustrate that, by adopting the technical solution of the present disclosure, the anti-scarring device forms a more uniform and dense gas protection layer on the wall surface of the reactor, reduces the temperature of the wall surface of the high temperature region, prevents the adhesion of powder particles on the wall surface, and effectively reduces TiCl₄The probability of scar deposition after circular seam is improved and TiCl is improved₄The scab phenomenon after the circular seam, and the operation period of the oxidation reactor is prolonged.

The above examples merely represent embodiments of the present disclosure, which are described in more detail and detail, but are not to be construed as limiting the scope of the present disclosure. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the concept of the present disclosure, and these changes and modifications are all within the scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the appended claims.