A high boiling point impurity pre-distillation system for crude titanium tetrachloride containing high concentration of particulate matter

Abstract

This invention provides a pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter. The system includes: a pre-distillation column, in which rising titanium tetrachloride vapor gas, separated from the high-boiling-point impurities, is flash-distilled. Heat and mass transfer are utilized between the crude titanium tetrachloride spray solution and the rising titanium tetrachloride vapor gas gas to wash the rising gas particulate matter and effectively separate the high-boiling-point impurities, thereby directly supplying the gaseous product feed to a primary refining system; a pre-distillation pump tank, which receives the spray solution and partially transports the concentrated crude titanium tetrachloride liquid produced therein to the pre-distillation column reboiler; and the pre-distillation column reboiler, which superheats the received concentrated crude titanium tetrachloride liquid before sending it back to the pre-distillation column for further flash distillation. This pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter allows for the initial, separate interception of most solid particulate matter in the crude titanium tetrachloride.

Description

Technical Field

[0001] This invention relates to the field of titanium tetrachloride purification and preparation technology, and more specifically, to a pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter. Background Technology

[0002] In the production process of titanium tetrachloride by the boiling chlorination method, crude titanium tetrachloride is stored in a storage tank after being condensed by a condensation system. This crude titanium tetrachloride contains a large amount of solid particles (up to 20%), mainly unreacted rutile, petroleum coke, and high-boiling-point impurities such as zirconium chloride, aluminum chloride, niobium chloride, and ferric chloride. It also contains low-boiling-point impurities such as silicon tetrachloride and tin tetrachloride. The production process uses two refining systems: a primary refining system to separate high-boiling-point impurities, and a secondary refining system to separate low-boiling-point impurities. The primary refining system intercepts solid particles and removes dissolved high-boiling-point impurities such as ferric chloride, zirconium chloride, niobium chloride, and aluminum chloride. The primary refining system also involves adding oil to react with vanadium trichloride to remove vanadium trichloride.

[0003] In existing technology, the primary refining system uses a storage tank feed pump to deliver crude titanium tetrachloride to the bottom tank of the primary distillation column. The bottom pump then pumps most of the crude titanium tetrachloride to the primary distillation reboiler (horizontal) for heating to provide heat to the primary distillation column. A small portion is returned to the sludge spraying system of the preceding process as wastewater. The primary distillation reboiler heats the crude titanium tetrachloride to a superheated state and sprays it into the lower part of the primary distillation column through a feed orifice plate. Simultaneously, an oiling device is installed at the inlet of this orifice plate. The oil reacts chemically with vanadium oxychloride in the titanium tetrachloride, forming vanadium slag, which is then effectively separated by the refining system. The pressure drop generated by the orifice plate causes the superheated crude titanium tetrachloride material to flash evaporate in the primary distillation column, producing rising titanium tetrachloride vapor. The titanium tetrachloride and low-boiling-point impurities, carrying fine particulate matter, rise upwards, while high-boiling-point impurities and most of the particulate matter remain in the bottom tank of the primary distillation column. Simultaneously, the reflux liquid at the top of the column transfers heat and mass with the rising gas flow, effectively washing the particulate matter in the rising gas flow and physically separating the high-boiling-point impurities. The concentrated crude titanium tetrachloride falls back into the bottom tank of the primary distillation column. This process is continuously repeated to achieve effective separation of solid particulate matter, high-boiling-point impurities, and vanadium oxychloride.

[0004] The purification and preparation technology of titanium tetrachloride described above has certain advantages, but it also faces several technical bottlenecks in actual production. The main problem is that the presence of a large amount of particulate matter seriously affects the stability of production operation and product quality. First, the vaporized titanium tetrachloride and low-boiling-point impurity vapors, carrying particulate matter, react with the injected vegetable oil. The presence of particulate matter reduces the vanadium removal effect, requiring the addition of more oil for a complete chemical reaction. Excessive oil addition leads to product quality deterioration. Second, a large amount of fine particulate matter entering the primary distillation condenser with the material flows back to the primary distillation column bottom tank with the condensate, causing plate blockage and ultimately leading to system shutdown and poor system stability. Third, after prolonged operation, a large amount of fine particulate matter accumulates in the primary distillation reboiler, causing poor reboiler heating effect and, in severe cases, clogging of the heat exchanger and auxiliary pipelines. Finally, the high particulate matter content in the feed product leads to excessive particulate matter content in the primary refined product, resulting in product quality deterioration. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter, so that the interception function of most solid particulate matter in crude titanium tetrachloride is first realized separately in this system, thereby improving the production operation of the primary purification system and improving the product quality of titanium tetrachloride.

[0006] To solve the above-mentioned technical problems, the present invention provides a pre-distillation system for crude titanium tetrachloride containing high concentrations of particulate matter and high boiling point impurities, comprising:

[0007] The pre-distillation column flashes out rising titanium tetrachloride vapor gas after separation from high-boiling-point impurities. Heat and mass transfer are then conducted between the crude titanium tetrachloride spray solution and the rising titanium tetrachloride vapor gas gas to wash the rising gas particulate matter and effectively separate high-boiling-point impurities, which are then directly supplied to the primary purification system as gaseous product feed.

[0008] The pre-distillation pump tank receives the spray solution and partially transports the crude titanium tetrachloride concentrate produced therein to the pre-distillation tower reboiler.

[0009] The pre-distillation column reboiler overheats the received crude titanium tetrachloride concentrate before sending it to the pre-distillation column for further flash distillation.

[0010] Preferably, a scrubbing nozzle is provided below the top of the pre-distillation column. After the storage tank feed pump delivers the crude titanium tetrachloride solution stored in the crude titanium tetrachloride storage tank to the top of the pre-distillation column, the crude titanium tetrachloride solution undergoes heat and mass transfer with the rising titanium tetrachloride vapor flow through the scrubbing nozzle provided below it.

[0011] Preferably, the pre-distillation pump tank is equipped with a pre-distillation tower circulation pump and / or a pre-distillation underflow pump, wherein the pre-distillation tower circulation pump is used to deliver a portion of the crude titanium tetrachloride concentrate to the pre-distillation tower reboiler under high pressure, and the pre-distillation underflow pump is used to deliver a portion of the crude titanium tetrachloride concentrate to the mud spraying process.

[0012] Preferably, the bottom of the pre-distillation pump tank is conical.

[0013] Preferably, a herringbone baffle is provided at the waist of the pre-distillation column, and the spray solution and the rising titanium tetrachloride vapor flow undergo heat and mass transfer on the herringbone baffle.

[0014] Preferably, the pre-distillation column reboiler is two vertical heat exchangers with forced circulation and arranged in parallel.

[0015] Preferably, the pre-distillation column and the primary distillation reboiler are fed in parallel to convey the gaseous material to the bottom of the primary distillation column.

[0016] Preferably, the primary refining system is also used to discharge crude titanium tetrachloride solid particles from the primary distillation column bottom tank to the pre-distillation pump tank.

[0017] Preferably, in the pre-distillation system, a first feed valve is provided in the feed pipe at the front end of the pre-distillation tower, and a sludge inlet valve is provided in the sludge inlet pipe at the front end of the pre-distillation pump tank; in the primary refining system, a second feed valve is provided in the feed pipe at the front end of the primary distillation tower reboiler, and a sludge discharge valve for connecting with the mud spraying process is provided in the sludge discharge pipe at the rear end of the primary distillation tower reboiler pump.

[0018] Preferably, the pre-distillation system has a target interception rate of 80% or higher for solid particulate matter.

[0019] Compared with the prior art, the pre-distillation system for crude titanium tetrachloride high-boiling-point impurities containing high concentrations of particulate matter described in this invention has the following beneficial effects:

[0020] 1) After treatment by the pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter, the content of solid particulate matter in the gas phase was reduced to 4.8%, and the solid particulate matter removal rate of the system can reach 84%, which meets the production requirements.

[0021] 2) The concentrated material from the primary refining system is discharged to the pre-distillation pump tank, where heat is fully utilized and particulate matter is further concentrated, reducing the system's wastewater discharge by 48% and improving evaporation efficiency.

[0022] 3) The efficient concentration and separation of solid particles in the entire production system and the significant reduction in the feed particle content of the primary refining system make the continuous operation of the primary refining system more stable and less prone to clogging. This solves the problem of system shutdown caused by solid particle blockage and extends the system operation cycle by more than 2 times. At the same time, the efficiency of separating high-boiling-point impurities and vanadium oxychloride from the primary refining product is significantly improved, and the product quality is significantly improved. Attached Figure Description

[0023] The accompanying drawings, which constitute a part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 This is a schematic diagram of the principle framework of the crude titanium tetrachloride high-boiling-point impurity pre-distillation system containing high concentrations of particulate matter in the entire production system according to the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1-Pre-distillation column, 2-Pre-distillation pump tank, 3-Pre-distillation column circulation pump, 4-Pre-distillation column reboiler, 5-Pre-distillation underflow pump, 6-Feed orifice plate, 7-Hinge baffle, 8-Scrubbing nozzle;

[0027] 100 - Crude titanium tetrachloride storage tank; 200 - Storage tank feed pump; 300 - First-stage distillation reboiler; 400 - First-stage distillation column; 500 - First-stage distillation column bottom tank; 600 - First-stage distillation column bottom pump.

[0028] 1000-Mud Spraying System. Detailed Implementation

[0029] To make the above-mentioned objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only some embodiments constituting the present invention, and are only used to explain the present invention and do not constitute a limitation thereof. Unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] The central idea of ​​this invention is to address the problem of current primary refining systems that integrate multiple functions, particularly particulate matter interception and vanadium removal from vegetable oil, leading to clogging of tray heat exchangers and deterioration of product quality. This invention provides a pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter. This system isolates the interception of most solid particulate matter in the crude titanium tetrachloride. The gaseous product from the pre-distillation system is directly supplied to the primary distillation column, significantly improving the continuous and stable production capacity of the primary distillation column, making product quality indicators easier to control, and ensuring more thorough separation of high-boiling-point impurities. Furthermore, this system fully utilizes the heat from the titanium tetrachloride discharged from the primary refining system, concentrating it before discharge, thus reducing the amount of wastewater discharged from the refining system and minimizing system heat loss.

[0031] Example 1

[0032] See Figure 1 As shown, the present invention provides a pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter, comprising:

[0033] Pre-distillation column 1 flash-distills rising titanium tetrachloride vapor gas after separation from high-boiling-point impurities. Heat and mass transfer are carried out between the crude titanium tetrachloride spray solution and the rising titanium tetrachloride vapor gas gas to wash the rising gas particulate matter and effectively separate high-boiling-point impurities, and then directly supply the gas phase product feed to the primary purification system.

[0034] Pre-distillation pump tank 2 receives the spray solution and partially transports the crude titanium tetrachloride concentrate produced therein to the pre-distillation tower reboiler 4.

[0035] The pre-distillation tower reboiler 4 overheats the received crude titanium tetrachloride concentrate before sending it to the pre-distillation tower 1 for flash distillation.

[0036] Specifically, on the one hand, the crude titanium tetrachloride concentrate heated to a superheated state by the reboiler 4 of the pre-distillation column is injected into the lower part of the pre-distillation column 1 through the feed orifice plate 6. Under the pressure drop of the feed orifice plate 6, flash evaporation occurs. In this process, titanium tetrachloride and low-boiling-point materials vaporize and flash evaporate to generate rising titanium tetrachloride vapor stream. The rising titanium tetrachloride vapor stream carries fine particulate matter upwards, while some high-boiling-point impurities and most of the particulate matter fall back to the bottom of the pre-distillation column 1, thereby completing the effective separation of high-boiling-point impurities.

[0037] On the other hand, a scrubbing nozzle 8 can be installed below the top of the pre-distillation column 1. After the storage tank feed pump 200 transports the crude titanium tetrachloride solution stored in the crude titanium tetrachloride storage tank 100 to the top of the pre-distillation column 1, the crude titanium tetrachloride solution will undergo heat and mass transfer with the rising titanium tetrachloride vapor flow through the scrubbing nozzle 8 installed below it, thereby completing the washing of the rising gas flow particles. The interior of the scrubbing nozzle 8 can be arranged in a spiral shape.

[0038] Therefore, the pre-distillation system for high-boiling-point impurities in crude titanium tetrachloride containing high concentrations of particulate matter, as described in this invention, can directly supply gaseous product feed to the primary refining system. In other words, the interception function of most solid particulate matter in crude titanium tetrachloride can be achieved separately in this system first, thereby improving the production operation of the primary refining system and improving the product quality of titanium tetrachloride.

[0039] Of course, after the above heat and mass transfer, the spray solution of crude titanium tetrachloride will carry some high-boiling-point impurities and most of the solid particles back to the pre-distillation pump tank 2 through the bottom pipe of the pre-distillation tower 1. The solid particles and high-boiling-point impurities in the pre-distillation pump tank 2 are concentrated into crude titanium tetrachloride concentrate with a higher concentration of solid particles.

[0040] Preferably, the pre-distillation pump tank 2 is equipped with a pre-distillation tower circulation pump 3 and / or a pre-distillation underflow pump 5, wherein the pre-distillation tower circulation pump 3 is used to transport part of the crude titanium tetrachloride concentrate to the pre-distillation tower reboiler 4 under high pressure, and the pre-distillation underflow pump 5 is used to transport part of the crude titanium tetrachloride concentrate to the mud spraying process.

[0041] Specifically, a large amount of solid particles are conveyed under high pressure by the pre-distillation column circulating pump 3, propelling the particles into the bottom of the pre-distillation column 1 without clogging the reboiler 4. Furthermore, when the column is shut down, all materials can fall back normally into the bottom of the pre-distillation column 1, preventing the accumulation of solid particles that could clog the reboiler 4. A portion of the crude titanium tetrachloride concentrate is also transported via the pre-distillation underflow pump 5 to the slurry spraying system 1000 in the slurry spraying process, which can more efficiently separate the solid particles, significantly reducing the amount of slag discharged and heat loss in the primary refining system.

[0042] In one preferred embodiment of the present invention, the bottom of the pre-distillation pump tank 2 is conical to facilitate the aggregation of solid particles, which are then discharged to the mud spraying process by the pre-distillation underflow pump 5 to reduce the amount of sewage discharged.

[0043] Preferably, a herringbone baffle 7 is provided at the waist of the pre-distillation column 1, and the spray solution and the rising titanium tetrachloride vapor flow undergo heat and mass transfer on the herringbone baffle 7.

[0044] Specifically, the feed spray solution from the top of the crude titanium tetrachloride column and the rising titanium tetrachloride vapor flow undergo heat and mass transfer on the herringbone baffle 7. On the one hand, this eliminates the need for a tower plate to avoid the shutdown of the pre-distillation system caused by high-concentration solid particles clogging the sieve holes. On the other hand, it ensures the gas-liquid contact area of ​​the pre-distillation column 1, thus guaranteeing better mass and heat transfer performance.

[0045] Preferably, the pre-distillation column reboiler 4 is two vertical heat exchangers with forced circulation and arranged in parallel.

[0046] Specifically, the two vertical heat exchangers can be switched between each other. That is, when the heat exchange effect of the pre-distillation tower reboiler 4 decreases, they can be switched online without affecting the stable operation of the system. Of course, the crude titanium tetrachloride concentrate can be either bottom-in or top-out during the circulation process of the pre-distillation tower reboiler 4A or pre-distillation tower reboiler 4B.

[0047] Preferably, the pre-distillation column 1 and the primary distillation reboiler 300 are fed in parallel to transport the gaseous material to the bottom of the primary distillation column 400.

[0048] Specifically, unlike traditional distillation columns, pre-distillation column 1 does not require a top condenser. The gaseous material directly enters the bottom of the primary distillation column 400 as feed for the primary purification system. This eliminates the need for condensation followed by reheating and vaporization, significantly saving energy. Furthermore, the parallel feeding method with the primary distillation reboiler 300 ensures consistency in the feed method within the primary purification system, thereby guaranteeing that the separation capacity of the primary distillation column 400 remains unaffected.

[0049] Preferably, the primary refining system is also used to discharge crude titanium tetrachloride solid particles from the primary distillation column bottom tank 500 to the pre-distillation pump tank 2.

[0050] Specifically, through the pre-distillation system of this invention, although the concentration of crude titanium tetrachloride solid particles after concentration is relatively low in the primary refining system, the temperature still reaches above 140°C. This setup allows for full utilization of the heat from the titanium tetrachloride, significantly reducing wastewater discharge and heat loss. The wastewater from the crude titanium tetrachloride solid particles can still be discharged via the primary distillation column bottom pump 600, while the bottom liquid in the pre-distillation column 1, after further concentration, can contain a higher concentration of solid particles, which is then discharged to the slurry spraying process via the pre-distillation underflow pump 5.

[0051] Preferably, in the pre-distillation system, a first feed valve is provided in the feed pipe at the front end of the pre-distillation tower 1, and a sludge inlet valve is provided in the sludge inlet pipe at the front end of the pre-distillation pump tank 2; in the primary refining system, a second feed valve is provided in the feed pipe at the front end of the primary distillation tower bottom tank 500, and a sludge discharge valve for connecting with the mud spraying process is provided in the sludge discharge pipe at the rear end of the primary distillation tower bottom pump 600.

[0052] Specifically, the original feed and sewage pipelines of the primary refining system remain unchanged. If the pre-distillation system malfunctions, the corresponding valves can be closed, and production can continue according to the original process flow. This achieves the purpose of removing solid particles while ensuring that the normal operation of the entire production system is not affected by any abnormalities in the pre-distillation system.

[0053] Preferably, the pre-distillation system has a target interception rate of 80% or higher for solid particulate matter.

[0054] Specifically, the pre-distillation system of the present invention does not need to intercept all solid particles. A target interception rate of 80% or higher is sufficient to fully meet the purification and preparation requirements of titanium tetrachloride. Furthermore, the pre-distillation tower 1 does not require reflux, and the heat load is not increased compared to the original primary purification system.

[0055] In summary, the pre-distillation system of this invention avoids the problem of concentrating all the functions of the primary purification system on a single distillation column in the traditional process of preparing titanium tetrachloride via the boiling chlorination method. This solves problems such as solid particulate matter clogging of the tower plates, pipe heat exchangers, and difficulties in product quality control, significantly improving the stable operation cycle of the equipment and product quality. With the application of the crude titanium tetrachloride pre-distillation system, the amount of wastewater discharged from the purification system was reduced by 48%, and the heating and evaporation load was correspondingly reduced by 14%, achieving energy saving and consumption reduction.

[0056] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A crude titanium tetrachloride pre-distillation system with high concentration of particulate matter, characterized in that, The high-boiling impurity pre-distillation system for the crude titanium tetrachloride containing high-concentration particles can directly supply a gas-phase product feed to a primary refining system, which includes a primary distillation reboiler (300), a primary distillation column (400), a primary distillation column tank (500), and a primary distillation column tank pump (600); The high-boiling impurity pre-distillation system for the crude titanium tetrachloride containing high-concentration particles includes: A pre-distillation column (1) in which the rising titanium tetrachloride vapor stream separated from the high-boiling impurities is flashed out, and the rising titanium tetrachloride vapor stream is used for heat and mass transfer with the spraying solution of the crude titanium tetrachloride to wash the particles in the rising stream and effectively separate the high-boiling impurities, thereby directly supplying a gas-phase product feed to a primary refining system; A pre-distillation pump tank (2) that receives the spraying solution and transports part of the concentrated crude titanium tetrachloride liquid generated by concentration in the pre-distillation pump tank to a pre-distillation column reboiler (4); The pre-distillation column reboiler (4) superheats the received concentrated crude titanium tetrachloride liquid for transportation to the pre-distillation column (1) for further flash treatment; The concentrated crude titanium tetrachloride liquid heated to a superheated state by the pre-distillation column reboiler (4) is sprayed into the lower part of the pre-distillation column (1) through the feed orifice plate (6) of the pre-distillation column (1) and flashes under the pressure drop of the feed orifice plate (6), wherein the titanium tetrachloride and low-boiling materials vaporize and flash to generate a rising titanium tetrachloride vapor stream, the rising titanium tetrachloride vapor stream carries fine particles upward, and part of the high-boiling impurities and most of the particles fall back to the column sump of the pre-distillation column (1), thereby effectively separating the high-boiling impurities; A pre-distillation column (1) is provided with a washing spray head (8) below the column top, and the crude titanium tetrachloride solution stored in the crude titanium tetrachloride storage tank (100) is transported to the column top of the pre-distillation column (1) by the storage tank feed pump (200), and the crude titanium tetrachloride solution is used for heat and mass transfer with the rising titanium tetrachloride vapor stream through the washing spray head (8) provided below the column top; The pre-distillation pump tank (2) is provided with a pre-distillation column circulating pump (3) and / or a pre-distillation bottom stream pump (5), wherein the pre-distillation column circulating pump (3) is used for high-pressure transportation of part of the concentrated crude titanium tetrachloride liquid to the pre-distillation column reboiler (4), and the pre-distillation bottom stream pump (5) is used for transportation of part of the concentrated crude titanium tetrachloride liquid to the mud spraying process; The pre-distillation column (1) and the primary distillation reboiler (300) adopt a parallel feeding mode to transport the gas-phase material to the bottom of the primary distillation column (400); The primary refining system is also used for discharging the solid particles of the crude titanium tetrachloride in the primary distillation column tank (500) to the pre-distillation pump tank (2); The target interception rate of the pre-distillation system for solid particles is greater than or equal to 80%.

2. A high boiling point impurities pre-distillation system of crude titanium tetrachloride containing high concentration of particulate matter as claimed in claim 1 wherein, The bottom of the pre-distillation pump tank (2) is conical.

3. A high boiling point impurities pre-distillation system of crude titanium tetrachloride containing high concentration of particulate matter as claimed in claim 1 wherein, The pre-distillation column (1) is provided with a herringbone baffle (7) at the column waist, and the spraying solution and the rising titanium tetrachloride vapor stream perform heat and mass transfer on the herringbone baffle (7).

4. A high boiling point impurities pre-distillation system of crude titanium tetrachloride containing high concentration of particulate matter as claimed in claim 1 wherein, The pre-distillation column reboiler (4) is two forced-circulation vertical heat exchangers arranged in parallel.

5. A high boiling point impurities pre-distillation system of crude titanium tetrachloride containing high concentration of particulate matter as claimed in claim 1 wherein, In the pre-distillation system, a first feeding valve is arranged in the front end of the feeding pipeline of the pre-distillation tower (1), and a sewage feeding valve is arranged in the front end of the sewage pipeline of the pre-distillation pump tank (2); in the first refining system, a second feeding valve is arranged in the front end of the feeding pipeline of the first distillation tower kettle (500), and a sewage valve for conducting with the mud spraying process is arranged in the rear end of the sewage pipeline of the first distillation tower kettle pump (600).

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