Fluidizing chlorination process for preventing sintering of furnace bottom material during starting of chlorination furnace

Abstract

The invention provides a fluidizing chlorination process for preventing sintering of a furnace bottom material during starting of a chlorination furnace. The fluidizing chlorination process comprises the following steps: A) arranging a combined gas distribution plate in the chlorination furnace; the combined gas distribution plate comprises a gas distribution bottom plate, a prefabricated part and a square box with holes, the prefabricated part is nested in the holes of the square box with holes and arranged on the surface of the gas distribution bottom plate, the gas distribution bottom plate is provided with gas distribution holes, the prefabricated part is provided with a central through hole, the central through hole and the gas distribution holes are coaxially arranged, and the central through hole is communicated with the square box with the holes. The diameter of the central through hole is equal to that of the air distribution holes; the inside of the square box with holes is hollow; b) introducing nitrogen into the chlorination furnace, and fully paving preheated reaction powder on the surface of the combined gas distribution plate; and C) continuously adding the powder and synchronously introducing chlorine for reaction to prepare titanium tetrachloride. Powder is preheated, the initial temperature of reaction is met, meanwhile, the square box is of a hollow structure, the heat insulation effect is achieved, and therefore material sintering is prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a boiling chlorination process for preventing sintering of materials at the bottom of a chlorination furnace when the furnace is started. Background Art

[0002] At present, the main method for producing titanium tetrachloride is boiling chlorination, that is, mixing titanium raw materials rich in TiO2 with petroleum coke in a certain proportion, adding chlorine gas to carry out a closed chemical reaction in a chlorination furnace. The reaction temperature is generally greater than 900°C, and titanium tetrachloride is obtained after the reaction. However, due to the natural endowment of titanium-containing ores in my country, the natural raw ore is mainly vanadium-titanium magnetite, which has high calcium and magnesium content. The processing cost of preparing titanium raw materials with TiO2 ≥ 90% and CaO + MgO ≤ 1.5% required by the traditional boiling chlorination process is high, the process is long, and the difficulty is great. After years of intensive research, Panzhihua Iron and Steel has gradually formed a process route for the simultaneous preparation of titanium tetrachloride by treating titanium-containing blast furnace slag based on the "high temperature carbonization-low temperature chlorination" process.

[0003] The low-temperature chlorination process is mainly carried out in a boiling chlorination furnace. In terms of the start-up of the boiling chlorination furnace, patent CN108928849B discloses a low-temperature chlorination furnace preheating device and a low-temperature chlorination furnace start-up method. The chlorination furnace is preheated with an inert gas and then carbonized slag at a suitable temperature is added to react with chlorine to heat up the furnace. Patent CN103011267B provides a low-temperature boiling chlorination process, first adding cold carbonized blast furnace slag, then using nitrogen at 650-700°C to heat the carbonized slag to 350-380°C, and then introducing chlorine to react.

[0004] The above patents all have their own advantages to a certain extent, but in the process of preparing titanium tetrachloride using titanium carbide as raw material, they are still unable to solve the problem of sintering of materials at the bottom of the chlorination furnace when starting up, and the problem of wear and difficulty in repairing the gas outlet of the gas distribution plate. Summary of the invention

[0005] The purpose of the present invention is to provide a boiling chlorination process for preventing sintering of materials at the bottom of a chlorination furnace when starting up. The boiling chlorination process of the present invention can simultaneously solve the problem of sintering of materials at the bottom of a chlorination furnace when starting up in a process for preparing titanium tetrachloride using titanium carbide as a raw material, as well as the problem of wear and difficulty in repairing a gas outlet of a gas distribution plate, and has the advantages of simple equipment, high efficiency, stability, etc.

[0006] The present invention provides a boiling chlorination process for preventing sintering of materials at the bottom of a chlorination furnace when the furnace is started, comprising the following steps:

[0007] A) a combined gas distribution plate is arranged in the chlorination furnace;

[0008] The combined gas distribution plate comprises a gas distribution bottom plate, a prefabricated part and a square box with holes. The prefabricated part is embedded in the hole of the square box with holes and is arranged on the surface of the gas distribution bottom plate.

[0009] The gas distribution bottom plate has gas distribution holes, the preform has a central through hole, the central through hole is coaxially arranged with the gas distribution hole, and the diameter of the central through hole is equal to the diameter of the gas distribution hole;

[0010] The square box with holes is hollow inside;

[0011] B) nitrogen is introduced into the chlorination furnace, and the preheated reaction powder is fully spread on the surface of the combined gas distribution plate;

[0012] C) continuously adding powder and simultaneously introducing chlorine gas to react and prepare titanium tetrachloride.

[0013] Preferably, the air distribution holes are evenly distributed on the gas distribution bottom plate.

[0014] Preferably, the preforms are made of ceramic material; the number of the preforms is the same as the number of air holes.

[0015] Preferably, the prefabricated component is horizontally placed on the surface of the gas distribution base plate, or is installed on the gas distribution base plate through a threaded structure.

[0016] Preferably, the square box with holes includes a multi-hole square box and / or a single-hole square box, and the height of the square box with holes is 30-70 mm.

[0017] Preferably, the height of the prefabricated part is the same as the height of the porous square box, so that the working surface of the combined gas distribution plate is a horizontal plane.

[0018] Preferably, the preheating temperature of the reaction powder preheated in step B) is 60% to 95% of the reaction temperature.

[0019] Preferably, the height of the reaction powder in step B) is 100 to 300 mm.

[0020] Preferably, the fluidization number in step B) is 1.0 to 3.0.

[0021] Preferably, the solid raw material for the chlorination reaction in step C) is slag containing titanium carbide, and the reaction temperature is 450-700°C.

[0022] The invention provides a boiling chlorination process for preventing sintering of furnace bottom materials during the start-up of a chlorination furnace, comprising the following steps: A) arranging a combined gas distribution plate in the chlorination furnace; the combined gas distribution plate comprises a gas distribution bottom plate, a prefabricated part and a square box with holes, the prefabricated part is nested in the hole of the square box with holes and arranged on the surface of the gas distribution bottom plate, the gas distribution bottom plate has gas distribution holes, the prefabricated part has a central through hole, the central through hole is coaxially arranged with the gas distribution hole, and the diameter of the central through hole is equal to the diameter of the gas distribution hole; the square box with holes is hollow inside; B) nitrogen is introduced into the chlorination furnace, and preheated reaction powder is fully spread on the surface of the combined gas distribution plate; C) powder is continuously added and chlorine is introduced simultaneously to react, so as to prepare titanium tetrachloride.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1) Through reasonable functional division, the distribution plate is designed as a combined structure, including a gas distribution bottom plate, a prefabricated part and a square box. After the combination is completed, the working surface of the distribution plate is still a plane, which can greatly reduce the fluidization dead zone;

[0025] 2) The gas outlet on the combined gas distribution is a prefabricated part made of ceramic structure to ensure wear resistance and also meet the requirements of damage replacement.

[0026] 3) Preheating the powder to meet the initial temperature of the reaction, and the hollow structure of the square box has a heat-insulating effect, thereby overcoming the problem of poor powder fluidity caused by condensation of titanium tetrachloride gas generated at the beginning of the reaction, thereby preventing material sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 A diagram illustrating the relative positions of the combined gas distribution plates used in the embodiment of the present invention;

[0029] Figure 1 In the figure, the blue boxes are nine-hole boxes and single-hole boxes;

[0030] Figure 2 It is a schematic diagram of the structure of the prefabricated part in the present invention;

[0031] Figure 3 A schematic diagram of the structure of a nine-hole square box used in an embodiment of the present invention;

[0032] Figure 4 A schematic diagram of the structure of a single-hole square box used in an embodiment of the present invention;

[0033] Figure 5 It is a structural schematic diagram of the combined gas distribution plate of the present invention;

[0034] Figure 4 In the figure, 1 is a gas distribution bottom plate, 2 is a porous square box, 3 is a prefabricated part, 4 is a gas distribution hole, and 5 is a through hole of the prefabricated part. DETAILED DESCRIPTION

[0035] The present invention provides a boiling chlorination process for preventing sintering of materials at the bottom of a chlorination furnace when the furnace is started, comprising the following steps:

[0036] A) a combined gas distribution plate is arranged in the chlorination furnace;

[0037] The combined gas distribution plate comprises a gas distribution bottom plate, a prefabricated part and a square box with holes. The prefabricated part is embedded in the hole of the square box with holes and is arranged on the surface of the gas distribution bottom plate.

[0038] The gas distribution bottom plate has gas distribution holes, the preform has a central through hole, the central through hole is coaxially arranged with the gas distribution hole, and the diameter of the central through hole is equal to the diameter of the gas distribution hole;

[0039] The square box with holes is hollow inside;

[0040] B) nitrogen is introduced into the chlorination furnace, and the preheated reaction powder is fully spread on the surface of the combined gas distribution plate;

[0041] C) continuously adding powder and simultaneously introducing chlorine gas to react and prepare titanium tetrachloride.

[0042] After the sealing gasket and the combined gas distribution plate are installed on the chlorination furnace, an air tightness test is performed and the furnace that passes the test is ready for use.

[0043] In the present invention, the combined gas distribution plate comprises a gas distribution bottom plate, a prefabricated component and a square box with holes.

[0044] In the present invention, the gas distribution bottom plate has gas distribution holes, and the gas distribution holes are evenly distributed on the gas distribution bottom plate. In one embodiment of the present invention, the gas distribution holes are preferably circular holes.

[0045] In the present invention, the preform is embedded in the hole of the perforated square box, and the two are arranged together on the surface of the gas distribution bottom plate. The difference between the hole diameter of the porous square box and the diameter of the preform is ≤1 mm.

[0046] In the present invention, the preform is preferably made of ceramic material, and the preform has a central through hole. The central through hole is coaxially placed with the air distribution hole to form a through gas passage, and the diameter of the central through hole is equal to the diameter of the air distribution hole to ensure smooth flow of the gas passage; the number of the preforms is the same as the number of the air distribution holes.

[0047] In the present invention, the height of the preform is preferably equal to the height of the square box with holes, so that the final working surface of the combined gas distribution plate remains at a horizontal plane, which can significantly reduce the fluidization dead zone.

[0048] In the present invention, the prefabricated component can be directly placed horizontally on the surface of the gas distribution bottom plate, or installed on the gas distribution bottom plate through a threaded structure.

[0049] In the present invention, the perforated square box includes a multi-hole square box and / or a single-hole square box. The multi-hole square box, such as a four-hole square box, a six-hole square box, a nine-hole square box, etc., is used in combination with a single-hole square box to meet the use of gas distribution bottom plates of different shapes, sizes and different air distribution hole arrangements, so that the combination of the prefabricated part and the perforated square box can completely cover all air distribution holes. Any two square boxes are connected by spot welding.

[0050] In the present invention, the square box with holes contains a prefabricated part, and the distance between the prefabricated part and the inner surface of the square box is preferably 0.5-1 mm.

[0051] In the present invention, the square box with holes is preferably made of steel material. The inside of the square box with holes is hollow and has a heat-insulating effect, thereby overcoming the problem of poor powder fluidity caused by condensation of titanium tetrachloride gas generated at the beginning of the reaction, thereby preventing material sintering; the wall thickness of the square box with holes is preferably 3 to 6 mm.

[0052] Nitrogen is introduced and enters the chlorination furnace through the small holes in the combined gas distribution plate, and then the preheated reaction powder is added to fully cover the combined gas distribution plate.

[0053] In the present invention, the fluidization number (dimensionless) of the nitrogen is preferably 1.0 to 3.0, more preferably 1.5 to 2.5, such as 1.5, 2, 2.5, and preferably a range value with any of the above values ​​as the upper or lower limit.

[0054] In the present invention, the reaction powder preferably includes titanium carbide. In an embodiment of the present invention, slag containing titanium carbide can be used as the reaction powder; the value of the temperature for preheating the reaction powder is preferably 60% to 95% of the reaction temperature, more preferably 65% ​​to 90%, such as 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, preferably a range value with any of the above values ​​as the upper or lower limit. Specifically, in an embodiment of the present invention, the temperature for preheating the reaction powder is preferably 350 to 450°C, more preferably 380 to 420°C, such as 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, preferably a range value with any of the above values ​​as the upper or lower limit.

[0055] In the present invention, the height of the reaction powder is preferably 100 to 300 mm, more preferably 150 to 250 mm.

[0056] Finally, the reaction powder is continuously added and chlorine gas is introduced simultaneously to make the two react. The generated titanium tetrachloride gas leaves from the top of the chlorination furnace and is collected after cooling.

[0057] In the present invention, the reaction temperature is preferably 450-700°C, more preferably 550-600°C, such as 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, preferably a range value with any of the above values ​​as the upper or lower limit.

[0058] The invention provides a boiling chlorination process for preventing sintering of furnace bottom materials during the start-up of a chlorination furnace, comprising the following steps: A) arranging a combined gas distribution plate in the chlorination furnace; the combined gas distribution plate comprises a gas distribution bottom plate, a prefabricated part and a square box with holes, the prefabricated part is nested in the hole of the square box with holes and arranged on the surface of the gas distribution bottom plate, the gas distribution bottom plate has gas distribution holes, the prefabricated part has a central through hole, the central through hole is coaxially arranged with the gas distribution hole, and the diameter of the central through hole is equal to the diameter of the gas distribution hole; the square box with holes is hollow inside; B) nitrogen is introduced into the chlorination furnace, and preheated reaction powder is fully spread on the surface of the combined gas distribution plate; C) powder is continuously added and chlorine is introduced simultaneously to react, so as to prepare titanium tetrachloride.

[0059] Compared with the prior art, the present invention has the following advantages:

[0060] 1) Through reasonable functional division, the distribution plate is designed as a combined structure, including a gas distribution bottom plate, a prefabricated part and a square box. After the combination is completed, the working surface of the distribution plate is still a plane, which can greatly reduce the fluidization dead zone;

[0061] 2) The gas outlet on the combined gas distribution is a prefabricated part made of ceramic structure to ensure wear resistance and also meet the requirements of damage replacement.

[0062] 3) Preheating the powder to meet the initial temperature of the reaction, and the hollow structure of the square box has a heat-insulating effect, thereby overcoming the problem of poor powder fluidity caused by condensation of titanium tetrachloride gas generated at the beginning of the reaction, thereby preventing material sintering.

[0063] In order to further illustrate the present invention, a boiling chlorination process for preventing sintering of materials at the bottom of a chlorination furnace provided by the present invention is described in detail below in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0064] Example 1

[0065] According to the demand, a combined gas distribution plate with a diameter of 2.5m was designed and manufactured. Figure 1 This is a diagram of the distribution base and the location of the square box. The blue box is the designed location of the square box. The square box is welded with a 4mm thick steel plate. 12 of them are used. Figure 3 The nine-hole square box and 12 Figure 4 The single-hole square boxes shown are placed in combination, and the square boxes are connected by spot welding; Figure 2 The cylindrical ceramic structure preform shown in Example 1 has a height that is the same as the outer height of the square box, and the upper surface of the combined distribution plate is a horizontal plane after completion.

[0066] Slag containing 14±0.5% titanium carbide was used as raw material, and an experiment was carried out on a fluidized bed using the above-mentioned combined distribution plate. First, an airtightness test was carried out, and the test was qualified; then nitrogen was introduced to control the fluidization number (dimensionless number) to 1.5, and then reaction powder preheated to 370±20° C. was added and fully spread on the combined distribution plate with a full spreading height of 100 mm; finally, powder was continuously added and chlorine was introduced simultaneously to react, and the prepared titanium tetrachloride left the top of the chlorination furnace in the form of gas and was collected after cooling.

[0067] After 20 days of production test, the bottom of the chlorination furnace was disassembled for observation. It was found that there were mainly some powder on the combined distribution plate, and no large amount of sintering occurred.

[0068] Example 2

[0069] The combined distribution plate in Example 1 is used.

[0070] Slag containing 14±0.5% of titanium carbide was used as raw material, and the test was carried out on a fluidized bed using the above-mentioned combined distribution plate. First, an air tightness test was carried out, and the test was qualified; then nitrogen was introduced to control the fluidization number (dimensionless number) to 2.0, and then reaction powder preheated to 400±20°C was added, and the combined distribution plate was fully spread, and the full spread height was 200mm; finally, powder was continuously added and chlorine was introduced simultaneously, and a reaction occurred, and the prepared titanium tetrachloride left the top of the chlorination furnace in the form of gas, and was collected after cooling. After 20 days of production test, the bottom of the chlorination furnace was disassembled for observation, and some powder was mainly present on the combined distribution plate, and no large amount of sintering occurred.

[0071] Example 3

[0072] The combined distribution plate in Example 1 is used.

[0073] Slag containing 14±0.5% titanium carbide was used as raw material, and an experiment was carried out on a fluidized bed using the above-mentioned combined distribution plate. First, an airtightness test was carried out, and the test was qualified; then nitrogen was introduced to control the fluidization number (dimensionless number) to 2.5, and then reaction powder preheated to 430±20° C. was added and fully spread on the combined distribution plate with a full spreading height of 300 mm; finally, powder was continuously added and chlorine was introduced simultaneously to react, and the prepared titanium tetrachloride left the top of the chlorination furnace in the form of gas and was collected after cooling.

[0074] After 20 days of production test, the bottom of the chlorination furnace was disassembled for observation. It was found that there were mainly some powder on the combined distribution plate, and no large amount of sintering occurred.

[0075] Comparative Example 1

[0076] The combined distribution plate in Example 1 is used.

[0077] Slag containing 14±0.5% titanium carbide was used as raw material, and experiments were carried out on a fluidized bed using the above-mentioned distribution plate. First, an airtightness test was carried out, and the test was qualified; then nitrogen was introduced to control the fluidization number (dimensionless number) to 2.5. The surface of the distribution plate was not fully covered with preheated reaction powder, but powder at 430±20°C was directly and continuously added and chlorine was introduced simultaneously to react. After 3 hours of reaction, the furnace temperature dropped and the furnace bottom pressure increased by 30%, and the furnace was forced to stop. The bottom of the chlorination furnace was disassembled for observation, and a large amount of sintered material appeared on the distribution plate, and the height of the sintered material was about 1m.

[0078] Comparative Example 2

[0079] Only the gas distribution base plate in Example 1 was used as the gas distribution plate for production.

[0080] Slag containing 14±0.5% titanium carbide was used as raw material, and an experiment was carried out on a fluidized bed. First, an airtightness test was carried out, and the test was qualified; then nitrogen was introduced to control the fluidization number (dimensionless number) to 2.5, and then reaction powder preheated to 430±20° C. was added and fully spread on the combined distribution plate with a full spreading height of 300 mm; finally, powder was continuously added and chlorine was introduced simultaneously to react, and the prepared titanium tetrachloride left the top of the chlorination furnace in the form of gas and was collected after cooling.

[0081] After 15 days of production testing, the bottom of the chlorination furnace was dismantled for observation and it was found that sintering occurred on the combined distribution plate. The overall sintering height was about 0.4m and some chlorine gas channels were blocked.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A boiling chlorination process for preventing sintering of furnace bottom materials during chlorination furnace startup, comprising the following steps: A) a combined gas distribution plate is arranged in the chlorination furnace; The combined gas distribution plate comprises a gas distribution bottom plate, a prefabricated part and a square box with holes. The prefabricated part is embedded in the hole of the square box with holes and is arranged on the surface of the gas distribution bottom plate. The gas distribution bottom plate has gas distribution holes, the preform has a central through hole, the central through hole is coaxially arranged with the gas distribution hole, and the diameter of the central through hole is equal to the diameter of the gas distribution hole; The square box with holes is hollow inside; B) nitrogen is introduced into the chlorination furnace, and the preheated reaction powder is fully spread on the surface of the combined gas distribution plate; C) continuously adding powder and simultaneously introducing chlorine gas to react and prepare titanium tetrachloride.

2. The boiling chlorination process according to claim 1, characterized in that: The air distribution holes are evenly distributed on the gas distribution bottom plate.

3. The boiling chlorination process according to claim 1, characterized in that: The prefabricated parts are made of ceramic material; the number of the prefabricated parts is the same as the number of the air distribution holes.

4. The boiling chlorination process according to claim 1, characterized in that: The prefabricated component is horizontally placed on the surface of the gas distribution bottom plate, or is installed on the gas distribution bottom plate through a threaded structure.

5. The boiling chlorination process according to claim 1, characterized in that: The square box with holes includes a multi-hole square box and / or a single-hole square box, and the height of the square box with holes is 30-70 mm.

6. The boiling chlorination process according to claim 1, characterized in that: The height of the prefabricated part is the same as that of the porous square box, so that the working surface of the combined gas distribution plate is a horizontal plane.

7. The boiling chlorination process according to claim 1, characterized in that: The preheating temperature of the reaction powder preheated in step B) is 60% to 95% of the reaction temperature.

8. The boiling chlorination process according to claim 1, characterized in that: In the step B), the height of the reaction powder fully spread is 100 to 300 mm.

9. The boiling chlorination process according to claim 1, characterized in that: The fluidization number in step B) is 1.0 to 3.

0.

10. The boiling chlorination process according to claim 1, characterized in that: In the step C), the solid raw material for the chlorination reaction is slag containing titanium carbide, and the reaction temperature is 450-700°C.

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