Reactor and method for a carbochlorization process with a double-walled inlet tube

Abstract

The reactor has a double-walled inlet pipe for supplying a chlorinating agent-containing gas and providing protective gas shrouding at the end of the inlet pipe. The reactor includes a reactor vessel with a protective lining on its inner wall. The double-walled inlet pipe extends into the reactor vessel through the protective lining. The double-walled chlorine inlet pipe has an inner pipe, an outer pipe, and a peripheral space between the inner and outer pipes. The chlorinating agent-containing gas is injected into the reactor vessel through the inner pipe, and the protective gas is simultaneously injected into the reactor vessel from the outer pipe through the peripheral space between the inner and outer pipes to form protective gas shrouding around the end of the double-walled inlet pipe. The protective gas may be recycled from other parts of the process to recycle various materials produced from the carbochlorination process.

Description

TECHNICAL FIELD

[0001] The present invention generally relates to a reactor for a carbochlorination process having a double-walled inlet tube, a method for injecting a chlorinating agent-containing gas into a reactor vessel, such as a fluidized bed reactor, and a plant process arrangement comprising the reactor.

BACKGROUND ART

[0002] Titanium dioxide (TiO2) has many known commercial uses, including use as a pigment for many different materials. TiO2 is produced from titanium raw materials in various multi-step processes. One such process is the chloride process. The chloride process typically starts with the formation of titanium tetrachloride (TiCl4) by mixing a raw titanium-containing feedstock with gaseous chlorine in a fluidized bed reactor at a temperature of about 900°C to 1000°C in the presence of coke or other suitable carbonaceous material as a reducing agent in an exothermic reaction. The resulting gas stream released from the fluidized bed and discharged from the fluidized bed reactor comprises TiCl4 (as well as other by-products), which is then processed into TiO2 particles through other processing steps.

[0003] Current techniques for introducing chlorine gas or any other type of chlorinating agent into the fluidized bed during the carbochlorination reaction process use a single-walled inlet tube extending through a lining, usually a brick lining, that covers the inner surface of the reactor shell including the side walls, reactor bottom, and optionally the reactor top. However, the inlet tubes are chemically corroded, and mechanically and thermally corroded over time due to their constant contact with chlorine gas or other chlorinating agents and / or abrasives contained in the corrosive fluidized bed during the carbochlorination reaction process, as well as due to exposure to alternating thermal stresses during start-up and / or shutdown of operation. Unfortunately, the inlet tubes and / or the protective lining adjacent to the inlet tubes need to be replaced and / or repaired relatively frequently due to erosion and corrosion processes, increasing the cost and downtime for the production of TiO2.

[0004] Therefore, it is desirable to have a system, apparatus, and / or method that extends the effective life of the inlet pipe to the fluidized bed reactor and / or the protective lining adjacent to the inlet pipe while the carbochlorization process is taking place inside the fluidized bed reactor vessel, thereby reducing the maintenance costs and / or downtime of the fluidized bed reactor. [Overview of the project] [Means for solving the problem]

[0005] According to some non-limiting aspects of the present invention, the present invention provides a method for injecting a chlorinating agent-containing gas into a reactor vessel that can reduce mechanical erosion, thermal erosion, and / or chemical corrosion to a reactor, an inlet pipe into the reactor vessel and / or protective lining adjacent to the inlet, as well as a plant process configuration including a reactor.

[0006] In one non-limiting aspect of the present invention, a reactor for a carbochlorination process is provided. The reactor may include a reactor vessel having an inner wall, a protective lining on the inner wall, and a double-walled inlet pipe for a chlorinating agent-containing gas extending into the reactor vessel through the protective lining. The double-walled inlet pipe may include an inner pipe, an outer pipe surrounding the inner pipe, and a peripheral space between the inner pipe and the outer pipe. The chlorinating agent-containing gas can be introduced into the reactor vessel through the end of the inner pipe. A protective gas can be introduced into the reactor vessel through the end of the outer pipe in the peripheral space between the inner pipe and the outer pipe. In some non-limiting embodiments, the reactor includes two or more double-walled inlet pipes extending into the reactor vessel.

[0007] In another non-limiting aspect of the present invention, a method is provided for injecting a chlorinating agent-containing gas into a reactor vessel having a double-walled inlet tube for a carbochlorization process to form titanium tetrachloride from a titanium raw material using a carbonaceous material as a reducing agent. This method may include injecting the chlorinating agent-containing gas into the reactor vessel through the end of the inner pipe of the double-walled inlet tube. A protective gas may be simultaneously injected into the reactor vessel through the peripheral space between the ends of the inner and outer pipes of the double-walled inlet tube. In some arrangements, the protective gas can form a protective gas envelope (e.g., cloud, cushion, shell, and / or shroud) around the end of the inner pipe, and preferably around the end of the outer pipe as well. Thereafter, the protective cloud can protect the ends of the inner and / or outer pipes from chemical and / or physical erosion from particles and chloride process reactions occurring within the reactor vessel.

[0008] In a further non-limiting aspect of the present invention, a plant process configuration is provided for forming titanium tetrachloride from a titanium raw material using a carbochlorization process that uses a carbonaceous material as a reducing agent. The plant process configuration includes a reactor as described above.

[0009] The reactor may be any type of reactor configured to include a carbochlorization reaction, where a double-walled pipe can be used as the introduction system for the chlorinating agent. In some non-limiting embodiments, the reactor may be a fluidized bed reactor, a circulating fluidized bed reactor, a bubbling bed reactor, a jet bed reactor, a slugging bed reactor, a riser reactor, a vertical shaft (furnace type) reactor, a moving bed reactor, a cyclone reactor, or a reactor having various features from two or more of these types of reactors.

[0010] In some optional configurations, the chlorinating agent-containing gas may support and / or contain chlorine as a chlorinating agent to propel the carbochlorization process. In some configurations, the chlorinating agent-containing gas may contain other chlorinating agents to propel the carbochlorization process, such as phosgene (COCl2), carbon tetrachloride (CCl4), thionyl chloride (SOCl2), sulfuryl chloride (SO2Cl2), and / or mixtures thereof.

[0011] In some optional configurations, the end of the outer pipe may be coplanar with the inner surface of the protective lining, or it may extend beyond the inner surface of the protective lining into the reactor vessel. The end of the inner pipe may be coplanar with the end of the outer pipe, or it may extend beyond the end of the outer pipe into the reactor vessel, or it may be located in a recessed area within the end of the outer pipe. Thus, the outer pipe can also mechanically protect at least a portion of the inner pipe by shielding it from abrasive particles and / or larger objects in the reactor vessel during the carbochlorization process.

[0012] In some optional configurations, the peripheral space may extend around the entire outer circumference of the end of the inner pipe. This arrangement can ensure or facilitate the formation of a protective cloud of protective gas surrounding the exposed end of the inner pipe and / or the entire circumference. It can also facilitate the formation of a protective cloud of protective gas around the entire circumference of the end of the outer pipe. Depending on the cross-sectional shapes of the inner and outer pipes and / or the orientation of both pipes relative to each other, the peripheral space may be circumferential or annular in shape, extending around the outer surface of the outer pipe within the space between the inner and outer pipes, or may have other shapes. In some optional configurations, the peripheral space may be interrupted by ribs, standoffs, posts, partial end walls, or other types of supports and / or spacers between the outer circumference of the inner pipe and the inner circumference of the outer pipe in order to maintain the peripheral space between the inner and outer pipes.

[0013] In some optional configurations, the reactor may include other features. In some non-limiting examples, a titanium feedstock inlet may extend into the reactor vessel for injecting titanium feedstock into the reactor vessel, a carbon feedstock inlet may extend into the reactor vessel for injecting carbon feedstock into the reactor vessel, and / or an exhaust opening may be located at the upper end of the reactor vessel for discharging a gas stream containing titanium tetrachloride from the reactor. Optionally, the titanium feedstock inlet and / or the carbon feedstock inlet may be double-walled pipes similar to the double-walled inlet pipes for the chlorinating agent-containing gas. Optionally, one or more additional double-walled inlet pipes as described above may extend into the reactor to provide an additional supply of chlorinating agent-containing gas into the reactor. One or more of the titanium raw material inlet tube, carbon raw material inlet tube, and double-walled inlet tube may be formed at the bottom of the reactor vessel, for example, extending into the reactor near the bottom end of the reactor vessel through the conical bottom wall of the reactor vessel to allow and / or facilitate the upward flow of the chlorinating agent and the gases generated during the carbochlorization reaction.

[0014] In some optional configurations, the protective lining may include heat-resistant refractory materials. The protective lining is selected to protect the inner surface of the reactor vessel shell, or other inner walls surrounding the carbochlorization reaction area within the reactor, from the damaging effects of the heat and / or chemical reactions that occur during the carbochlorization process. For example, the protective lining may include and / or be formed from refractory bricks lining the inner walls of the reactor vessel. However, other types and / or forms of refractory materials, such as monolithic refractory lining and / or pourable refractory materials, can be used to form the protective lining along the inner surface of the inner walls of the reactor vessel shell to protect the reactor vessel shell. The protective lining may include non-refractory materials.

[0015] In some optional configurations, a chlorinating agent-containing gas is injected into the reactor vessel through the inner pipe at a first rate, and a protective gas is injected into the reactor vessel at a second rate through the peripheral space between the inner and outer pipes, with the second rate being greater than or equal to the first rate. This allows the protective gas to create a protective gas envelope around the end of the inlet pipe and / or push the abrasive bed of the fluidized bed away from the double-walled inlet pipe and, optionally, the adjacent lining.

[0016] In some optional configurations, the chlorinating agent-containing gas may be injected at a first temperature, and the protective gas may be injected at a second temperature. Preferably, the second temperature is lower than the first temperature, which can help reduce the corrosion rate by lowering the temperatures of the inner and outer tubes.

[0017] In some optional configurations, the protective gas may include one or more inert gases such as carbon monoxide (CO), carbon dioxide (CO2), nitrogen gas (N2), and / or another inert gas, as well as mixtures thereof. The inert gas can provide a protective gas envelope (e.g., cloud, shroud) around the chlorinating agent-containing gas directly adjacent to the end of the double-walled inlet pipe, so that the reaction with the floor material during the carbochlorization process does not occur directly at the pipe mouth and lining, but rather at a distance from the pipe mouth / outlet and over most of the fluidized bed.

[0018] In some optional configurations, the protective gas may include one or more reactive gases such as titanium tetrachloride (TiCl4), chlorine gas (Cl2), carbon tetrachloride (CCl4), and / or other reactive gases (e.g., COCl2, CO, etc.), and mixtures thereof. TiCl4 and / or Cl2 are particularly suitable as protective gases because they may originate from the carbochlorization process and are recycled within the plant, thereby providing improved efficiency and / or environmental characteristics of the carbochlorization process. When using a reactive gas as the protective gas, the temperature of the reactive gas is preferably at least about 100°C lower than the temperature of the chlorinating agent-containing gas flowing through the inner pipe. Preferably, the temperature of the reactive gas is also higher than the condensation temperature point of the protective gas and / or chlorinating agent-containing gas. This may prevent the gas from condensing and / or liquefying inside the pipe(s), which could cause undesirable chemical erosion and / or liquid accumulation, for example, by wetting the surface of the pipe and / or the surface of the protective lining.

[0019] In some optional configurations, the protective gas and / or protective agent for the protective gas may be at least partially recycled from another plant process, including a carbochlorination process, supplied from a fresh source, and / or supplied from a combination of a recycled source and a fresh source. For example, the protective gas may include recycled off-gas from a carbochlorination process, and the protective agent preferably includes CO2, CO, and / or mixtures thereof. The protective gas may optionally include recycled chlorinating agents from a carbochlorination process, preferably including Cl2, TiCl4, COCl2, and / or mixtures thereof. The plant process configuration may optionally include the supply of recycled protective gas from other processes in the plant process configuration, and / or the supply of new protective gas for supply to a double-walled inlet pipe. For example, the supply of recycled protective gas may optionally include at least one of recycled off-gas, recycled chlorinating agents, and mixtures thereof. Depending on the circumstances, the recyclable protection gas may be supplied from one or more process devices of the carbochlorization process, including, for example, an off-gas treatment device, a gas phase converter, a solid phase converter, and / or a combination thereof.

[0020] In some configurations and / or embodiments, the reactor and / or method and / or plant process configurations of the present invention can provide apparatus and systems that extend the usable life of one or more inlet pipes for injecting material into a fluidized bed reactor, for example, a carbochloration process of titanium raw materials, thereby reducing the maintenance costs and / or downtime (e.g., downtime) of the reactor.

[0021] These and other aspects, configurations, advantages, uses and / or characteristics of the present invention will become apparent upon consideration of the following detailed description and accompanying drawings. [Brief explanation of the drawing]

[0022] [Figure 1]is a schematic vertical cross-sectional view of a fluidized bed reactor according to certain non-limiting embodiments of the present invention. [Figure 2] is an enlarged schematic axial cross-sectional view of the end portion of the double-walled inlet pipe in the circled portion of Figure 1. [Figure 3] is a schematic end view of the double-walled inlet pipe. [Figure 4] is a schematic process diagram showing an exemplary plant process arrangement for supplying protective gas to the double-walled inlet pipe and the fluidized bed reactor. [Figure 5] is a schematic process diagram showing another exemplary plant process arrangement for supplying protective gas to the double-walled inlet pipe and the fluidized bed reactor. [Figure 6] is a schematic process diagram showing yet another exemplary plant process arrangement for supplying protective gas to the double-walled inlet pipe and the fluidized bed reactor. [Figure 7] is a schematic process diagram showing yet another exemplary plant process arrangement for supplying protective gas to the double-walled inlet pipe and the fluidized bed reactor. [Figure 8] is a schematic process diagram showing a further exemplary plant process arrangement for supplying protective gas to the double-walled inlet pipe and the fluidized bed reactor. [Figure 9] is a schematic process diagram showing yet another exemplary plant process arrangement for supplying protective gas to the double-walled inlet pipe and the fluidized bed reactor. [Figure 10] is a schematic process diagram showing yet another exemplary plant process arrangement for supplying protective gas to the double-walled inlet pipe and the fluidized bed reactor. [Mode for Carrying Out the Invention]

[0023] The following description is intended to illustrate the illustrated and / or various intended embodiments illustrated and / or related thereto. The illustrated embodiments are non-limiting examples and do not define the invention in themselves. Any feature illustrated and / or described in relation to one embodiment can be combined with any one or more features illustrated and / or described in relation to another embodiment. Any dimensions illustrated are illustrative and not intended to limit the scope of the invention. The term "a" is used herein as an open and comprehensive term to include, but is not limited to, one or more items described by it.

[0024] Referring here to Figures 1 to 3, a reactor 10 according to one non-limiting embodiment is configured to carry out and contain a carbochlorination process of a titanium raw material, in which a chlorinating agent-containing gas is combined with the titanium raw material and carbonaceous material at high temperature to form titanium tetrachloride in a manner well understood in the art. The titanium raw material may include, for example, rutile, synthetic rutile, high-grade ilmenite, titanium-containing slag, or any other titanium-containing raw material material suitable for treatment in a fluidized bed during the carbochlorination process to produce TiCl4 and / or other desired reaction products. As will be described in more detail below, the reactor 10 has one or more double-walled inlet pipes for introducing one or more chlorinating agents into the fluidized bed reactor, while providing the ability of protective gas shrouds at the ends of the double-walled inlet pipes.

[0025] The drawings relate to an illustrated, non-limiting, exemplary reactor 10 (typically referred to as a “fluidized bed reactor”) used to carry out a carbochlorization process using a fluidized bed to obtain TiCl4 from titanium raw materials, a chlorinating agent, and a carbonaceous material in an exothermic reaction, but the present invention is not necessarily limited to fluidized bed reactors. Rather, the present invention can be used in other types of reactors that can carry out carbochlorization reactions and can use double-walled pipes as an introduction system for chlorinating agents and / or other materials, such as circulating fluidized bed reactors, bubbling bed reactors, jet bed reactors, slugging bed reactors, riser type reactors, vertical shaft (furnace type) reactors, moving bed reactors, and / or cyclone reactors. Furthermore, the present invention is not limited to reactor vessels having the exact shape of the exemplary reactor in the drawings. Rather, the reactors of the present invention can have a variety of different geometric shapes, such as conical, cylindrical, or rectangular, with or without an interior and / or with or without a constant diameter. Additional details of some, though not all, types and geometric shapes of reactors suitable for containing carbochlorization processes are disclosed in "Spouted and Spout-Fluid Beds Fundamentals and Applications" by Norman Epstein and John R. Grace (Cambridge University Press, 2011), the contents of which are incorporated herein by reference in their entirety.

[0026] The reactor 10 includes a reactor vessel 12 having an outer shell 14 that extends between the upper and lower walls and forms side walls that define a sealed reaction space therein. In this example, the reactor vessel 12 is a conical-bottomed vessel having substantially cylindrical side walls, an inverted conical bottom wall, and a substantially convex upward dome shape for the top wall. However, other shapes and forms of the reactor vessel 12 are also possible. The outer shell 14 can be formed of a suitable material such as steel, stainless steel, or other appropriately strong material. A protective lining 16 is positioned along the radial inner surface of the inner wall 18 of the outer shell 14 to protect the inner wall from abrasion and / or corrosion by heat and / or chemicals inside the reactor vessel 12 during the carbochlorization process. The protective lining 16 preferably covers the entire inner surface of the inner side wall 18 and the bottom wall of the outer shell, and depending on the type of protective lining used, it may also cover all or part of the inner surface of the upper wall. The protective lining 16 is preferably made of a heat-resistant, and optionally chemically resistant, material, such as a refractory material. In this example, the protective lining 16 is formed of bricks lining the inner wall surface of the outer shell, but other types of refractory or protective materials, such as integral construction and / or cast materials, may be used. During use, the fluidized bed 20 is formed at the lower end of the reactor vessel 12, where the titanium raw material, carbonaceous material (e.g., coke particles), and chlorinating agent are mixed by one or more flows of gas, protective gas, process support gas (e.g., air), and chlorinating agent-containing gas generated by the carbochlorination reaction with the titanium-containing and carbonaceous materials, which flows upward from the bottom of the reactor and undergoes thermal expansion under exothermic conditions to form TiCl4 and other byproducts. The chlorinating agent may include one or more of chlorine, phosgene (COCl2), carbon tetrachloride (CCl4), thionyl chloride (SOCl2), sulfuryl chloride (SO2Cl2), and / or mixtures thereof. Other chlorinating agents suitable for promoting the carbochlorization reaction may be used. The solid and gas may be introduced (e.g., injected) into the reactor vessel in any suitable spatial relationship to each other that can form and / or maintain a working fluidized bed, for example, the gas enters from the bottom, the solid from the top, and / or at least a portion of the solid enters from the bottom through separate piping.

[0027] A double-walled inlet pipe 22 extends into the reactor vessel 12, for example, through the outer shell 14 and protective lining 16, supplying a flow of chlorinating agent-containing gas into the reactor vessel to facilitate the carbochlorization reaction in the fluidized bed 20. The end of the double-walled inlet pipe 22 is preferably located in the lower part of the reactor vessel 12, such as within or near the bottom cone of the vessel, as shown in Figures 2 and 3, to directly introduce the chlorinating agent into the fluidized bed 20, for example, by injecting the chlorinating agent-containing gas. The double-walled inlet pipe 22 has an inner pipe 24 and an outer pipe 26 surrounding the inner pipe, the inner pipe 24 being located inside the inner bore of the outer pipe and extending axially along the length (longitudinal axis) of the outer pipe. Preferably, the inner pipe 24 is substantially or substantially coaxial with the outer pipe 26. A peripheral space 28 (e.g., a circumferential or annular space) is defined between the outer surface of the inner pipe 24 and the inner surface of the outer pipe 26. Preferably, the inner pipe 24 and the outer pipe 26 are coaxially aligned such that the peripheral space 28 preferably has a constant distance S between the inner pipe and the outer pipe along the length of the double-walled inlet pipe around the entire circumference of the two pipes. During use, a gas containing a chlorinating agent is supplied into the reactor vessel 12 through the inner pipe 24, and a protective gas is supplied into the reactor vessel through the peripheral space 28 between the inner pipe and the outer pipe. In this way, the chlorinating agent-containing gas is injected directly into the fluidized bed area 20 through the end 30 of the inner pipe, and the protective gas is injected through the end 32 of the outer pipe in the peripheral space 28 surrounding the inner pipe. While it is typical for each of the inner pipe 24 and the outer pipe 26 to have a substantially circular cross-sectional shape, the inner pipe and / or the outer pipe may have other cross-sectional shapes such as elliptical, polygonal, or rectangular, and the term “periphery” is not limited to a circular peripheral shape and may include any shape extending around the outer circumference of the inner pipe between the outer circumference of the inner pipe and the inner circumference of the outer pipe.

[0028] As shown in the drawing, the end 32 of the outer pipe 26 is coplanar with the inner surface of the protective lining 16. In this configuration, the protective lining 16 can protect the outer surface of the outer pipe 26 from mechanical and / or chemical wear. In some configurations, the end 32 of the outer pipe 26 may extend into the reactor vessel 12 beyond the inner surface of the protective lining 16. The end 30 of the inner pipe 24 may be coplanar with the end 32 of the outer pipe 26, as shown in the drawing. However, in other configurations, the end 30 of the inner pipe 24 may extend into the reaction space slightly beyond the end 32 of the outer pipe, or the end 30 of the inner pipe 24 may be in a retracted position into the outer pipe from the end 32 of the outer pipe. In any configuration, it is preferable that the peripheral space 28 extends around the entire outer circumference of the inner pipe so that the protective gas reliably envelops at least the end 30 of the inner pipe 24, preferably both the inner pipe 24 and the outer pipe 26 ends 30, 32. However, some of the gaps in the peripheral space 28 may be formed by one or more ribs, posts, end wall sections, standoffs, or other types of spacers to separate the inner pipe and the outer pipe and form the peripheral space 28. In any case, such spacers do not completely close the peripheral space 28 at the end 32 of the outer pipe 26, and as a result, protective gases can flow through the end around the end 32 of the inner pipe 26.

[0029] Preferably, the velocity Vo of the protective gas flowing through the end 32 of the outer pipe 26 is at least equal to, and more preferably greater than, the velocity Vi of the chlorinating agent-containing gas flowing through the end 30 of the inner pipe 24. By transporting the protective gas at a velocity Vo higher than the velocity Vi of the chlorinating agent-containing gas (e.g., by pressurizing), the protective gas can form a protective gas envelope around the end of the double-walled pipe 22, which pushes the abrasive fluidized bed material away from the areas of the protective lining 16 directly adjacent to the ends of the inner pipe 24 and outer pipe 26 and the double-walled inlet pipe. In this way, the protective gas also prevents the chlorinating agent-containing gas from locally wetting adjacent surfaces of the piping 24 and 25 and the protective lining 16, thereby preventing the chlorinating agent from chemically corroding at least the end 30 of the inner pipe 24 and also typically at least partially protecting the end 32 of the outer pipe 26. As used herein, the term wetting refers to a surface phenomenon in which the chlorinating agent-containing gas does not form bubbles that exit the pipe directly into the fluidized bed, but instead spreads over the surface of the lining (and pipe) around the pipe outlet, coming into close contact with the lining (and pipe), and then, when it reaches a suitable temperature by the exothermic process, causes undesirable corrosion by reaction. The outer pipe 26 is also protected from mechanical abrasion by the surrounding protective lining 16. Thus, both the flow of protective gas and the reactor lining act to protect the outer pipe 26 from mechanical and chemical wear.

[0030] The reactor 10 may include additional features for carrying out the carbochlorization process. For example, a titanium raw material inlet pipe 34 may be provided to supply titanium-containing raw materials to the reactor vessel 12. A carbonaceous material inlet pipe 36 may be provided to supply carbonaceous materials, such as coke particles, into the reactor vessel 12. Typically, the main components of the solid materials (e.g., carbonaceous materials and titanium raw materials) are introduced into the reactor through one or more openings located above the level of the fluidized bed 20. In the non-limiting example shown in Figure 1, the inlet pipes 34 and 36 extend through the side walls into the interior of the reactor vessel 12 to introduce the titanium raw materials and carbonaceous materials above the height of the fluidized bed 20. However, in other configurations, the inlet pipes may be located in other areas of the reactor vessel, such as below the operating level of the fluidized bed 20, located through the top wall of the vessel and / or through the side walls of the outer mantle and / or through the bottom wall of the outer mantle. In this example, each of the titanium raw material inlet pipe 34 and the carbonaceous material inlet pipe 36 is shown as a single-walled pipe. However, in some configurations, one or more of the titanium raw material inlet pipes 34 and carbonaceous material inlet pipes 36 may also be double-walled inlet pipes similar to the double-walled inlet pipe 22, so that a protective gas can be transported through the outer pipe in the surrounding space to protect each end of these inlet pipes 34 and 36 as well. An exhaust opening 38 may be provided to allow the hot gas carrying TiCl4, particulate matter, and / or other materials to be captured from the fluidized bed region 20 and / or discharged from the reactor vessel 12 for further processing. The exhaust opening is preferably spaced above the top level of the fluidized bed 20. In this example, the exhaust opening 38 is located in the top wall of the outer shell, but it may also be located in other areas of the reactor vessel.

[0031] In use during the carbochlorination process, the chlorinating agent-containing gas is injected into the reactor vessel 12 through the inner end 30 of the inner pipe 24, while simultaneously, the protective gas is injected into the reactor vessel through the peripheral space 28 between the inner pipe 24 and the inner end 32 of the outer pipe 26. The protective gas is preferably transported at a higher velocity Vo than the velocity Vi of the chlorinating agent-containing gas (e.g., by pressurization), thereby generating a protective gas envelope around the ends 30 and 32 of the inlet pipes 24 and 26, pushing the abrasive material in the fluidized bed away from the pipes and adjacent linings. The flow of the protective gas also prevents the chlorinating agent-containing gas from locally wetting the piping and adjacent lining surfaces, thereby preventing the chlorinating agent from chemically corroding one or both ends of the inner pipe 24 and the outer pipe 26 or adjacent areas of the protective lining 16. The protective gas is preferably transported along the surrounding space 28 at a lower temperature than the chlorinating agent-containing gas in the inner pipe 24 in order to lower the temperature of the inner pipe 24 and reduce the corrosion rate. A method for injecting the chlorinating agent-containing gas is described herein with reference to the reactor 10 shown in the drawings, but this method can be used in fluidized bed reactors having different configurations and / or characteristics and is not limited to use in the reactor 10 shown in the drawings.

[0032] The protective gas may be any inert gas or mixture of gases that does not interfere with the carbochlorization reaction and helps protect pipes 24 and 26. As used herein, the term inert refers to materials and / or gases that do not participate in the primary carbochlorization reaction within reactor 10. For example, the protective gas may be one or more of carbon dioxide (CO2), carbon monoxide (CO), nitrogen (N2), and mixtures thereof, or may contain them. The inert gas provides a protective gas envelope around the chlorinating agent-containing gas, so that the reaction with the materials in the fluidized bed occurs at a distance within the fluidized bed rather than directly at the mouth and lining of the double-walled pipes 22. This prevents wetting of the protective lining 16 with chlorine. CO and CO2 are particularly suitable as inert gases because they can be recycled from various processes within the manufacturing plant. N2 may be used instead when recycling is not available. Such an inert protective gas may be introduced at any desired suitable temperature, but it is preferable that it be injected at a lower temperature than the chlorinating agent-containing gas.

[0033] In some configurations, the protective gas may be or contain one or more reactive gases. For example, the protective gas may contain reactive gases such as titanium tetrachloride (TiCl4), chlorine gas (Cl2), carbon tetrachloride (CCl4), carbon monoxide (CO), phosgene (COCl2), and / or mixtures thereof. Pure TiCl4 and Cl2 are particularly suitable as protective gases because they originate from the chloride process to form TiO2 and can be recycled from various processes within the manufacturing plant. When used as a protective gas, the temperature of the reactive gas is preferably at least 100°C lower than the chlorinating agent-containing gas flowing through the inner pipe 24. However, when used as a protective gas, the temperature of the reactive gas is also preferably above its own condensation point. For example, when pure TiCl4 is used, it is preferably a gas and has a temperature of at least 140°C before entering the outer pipe 26. In another example, when Cl2 is used, Cl2 is preferably a gas, particulate, and has a temperature of at least -30°C before entering the outer pipe. When phosgene is used as a protective gas, its temperature is preferably at least +9°C before it enters the outer tube.

[0034] The following sections provide some non-limiting exemplary dimensions, volume ratios, rates, and other data that can be used for reactor 10. However, it should be understood that these data are merely examples of some preferred configurations and are not limiting. The inner pipe 24 may have an inner diameter (di) between about 20 mm and about 200 mm, preferably between about 60 mm and about 160 mm, more preferably between about 100 mm and about 140 mm, and a wall thickness (ti) between about 4 mm and about 12 mm, preferably between about 6 mm and about 8 mm. The distance between the inner pipe 24 and the outer pipe 26 corresponding to the width (S) of the peripheral space 28 may be about 1 mm and about 6 mm, preferably between about 2 mm and about 3 mm. The wall thickness (to) of the outer pipe 26 may be between about 6 mm and about 15 mm, preferably between about 8 mm and about 12 mm. The relative height (projection distance) of the inner pipe 24 with respect to the protective lining 16 may be between approximately 0 mm (i.e., coplanar with the lining) and approximately 50 mm, and the end of the outer pipe 26 is substantially flush with the end of the inner pipe 24. The gas injection velocity (Vi) in the inner pipe 24 may be approximately 1 m / s to approximately 50 m / s, preferably approximately 5 m / s to approximately 25 m / s, and may depend on the location of the single discharge pipe and its hydrostatic pressure height. The gas injection velocity (Vo) in the outer pipe 26 (in the surrounding space 28) is preferably at least the same as velocity (Vi), and more preferably faster than velocity (Vi), although this is not necessarily required. For example, the Vi:Vo ratio (Vi:Vo) may be approximately 2:1 to approximately 1:2, preferably approximately 1:1 to approximately 1:2, and more preferably approximately 1:1.1 to approximately 1:1.6. The volumetric flow rate ratio (Vi:Vo) between the inner and outer pipes may be about 100:50 to about 100:1, preferably about 100:20 to about 100:5. The volumetric flow rate ratio may depend on the geometric shape of the pipe system. The reactive coolant and conductive gas introduced through the outer pipe 26 (in the surrounding space 28) may contain at least one or more of TiCl4, O2, CCl4, and mixtures thereof. The inert cooling gas and conductive gas in the outer pipe 26 may contain at least one or more of CO2, CO, N2, and mixtures thereof.The temperature of the reactive gases flowing through the outer pipe 26 may be higher than their condensation points and at least about 100°C lower than the temperature of the gases flowing through the inner pipe 24. The temperature of the inert gases flowing through the outer pipe 26 may be lower than the temperature of the reverse chlorine and can otherwise be freely selected within an appropriate range. The inclination of the double-walled pipe 22 may be between nearly vertical and nearly horizontal, preferably within about 30° of horizontal, more preferably within about 15° of horizontal, and even more preferably nearly horizontal. The inclination of the ends of the inner pipe 24 and the outer pipe 26 may be perpendicular to the axis of each pipe, but may be at other angles, for example, to accommodate any inclination of the outer surface of the protective lining 16 as needed. If necessary, other dimensions, rates, temperatures, ratios, angles, etc. may be used in other configurations and embodiments of the reactor 10.

[0035] Figures 4 to 10 show some non-limiting examples of plant process configurations adapted to supply one or more protective gases to the double-walled inlet pipe 22 for injecting a protective cloud of chlorinating agent and protective gas, as previously described. As previously stated herein, the protective gases may include one or more inert gases and / or reactive gases. These protective gases may be supplied from a fresh source and / or from recycled gases from the carbochlorination process. Similarly, the chlorinating agent may be supplied from a fresh source and / or recycled from the carbochlorination process.

[0036] Figure 4 schematically shows a non-limiting example of a plant process configuration 100 in which an inert protective gas is supplied from a fresh source to a double-walled inlet pipe 22. A protective agent tank 102 is supplied with a fresh / replenishment supply of protective agent. The protective gas containing the protective agent is supplied from the protective agent tank 102 to the outer pipe 26 of the double-walled inlet pipe 22, from which the protective gas is injected into the reactor 10 as described above. The protective agent in the fresh / replenishment supply is preferably carbon dioxide (CO2) and / or carbon monoxide (CO), but other protective agents are also possible. The chlorinating agent is supplied to the chlorinating agent tank 104 from, for example, a fresh / replenishment supply source of chlorinating agent. The chlorinating agent-containing gas is supplied from the chlorinating agent tank 104 to the inner pipe 24 from which the chlorinating agent-containing gas is injected into the reactor 10, as described above. As part of the downstream processing of TiCl4 and / or other gases, products, and / or by-products of the carbochlorization process occurring inside reactor 10, one or more different post-reaction processes can optionally be provided. For example, solids and gases discharged from fluidized bed reactor 10 can be separated in reactor discharge separator 106. Solid-phase material from reactor discharge separator 106 can be processed in solid-phase processing device 108. Solid material from solid-phase processing device 108 can be converted in solid-phase converter 110, from which by-products can be recovered and / or discharged for further processing. Gas-phase material from reactor discharge separator 106 can be separated in phase separator 112. Product-containing portions from gas-phase separator 112 can be processed in gas-phase converter 114, from which one or more final products can be obtained. Other off-gases from gas-phase separator 112 can be processed in off-gas processing device 116, from which one or more off-gases can be discharged.

[0037] Figure 5 schematically illustrates a non-limiting example of a plant process configuration 200 in which an inert protective gas is supplied from both a fresh and a recycled source to the double-walled inlet pipe 22 from the plant. In this example, recycled off-gas is recycled to be supplied to the double-walled inlet pipe 22 as protective gas. Off-gas from the off-gas treatment device 116 is returned to the protective agent tank 102 for reuse as a protective agent. The protective agent of the recycled off-gas source is preferably carbon dioxide (CO2) and / or carbon monoxide (CO), but other protective agents are also possible. Fresh protective agents can also be supplied to the protective agent tank as described above. In some configurations, off-gas can be obtained from other points in the post-discharge treatment from the reactor 10. The protective gas and chlorinating agent-containing gas are then supplied to the double-walled inlet pipe 22 for injection into the reactor 10 as described above. The remaining reactor post-treatment may, if applicable, be carried out substantially as described above in 106-116.

[0038] Figure 6 schematically illustrates a non-limiting example of a plant process configuration 300 in which the cooled reactive gas, intended for use as a protective gas as described above, is supplied to the double-walled inlet pipe 22, rather than using a separate protective agent for the protective gas. In this non-limiting example, a second flow of the chlorinating agent-containing gas is led from the chlorinating agent tank 104 to the chlorinating agent cooler 118, where it is cooled and then supplied for injection through the outer pipe 26 of the double-walled inlet pipe 22 as described above. The primary flow of the chlorinating agent-containing gas is supplied from the chlorinating agent tank to the inner pipe 24 as described above. The protective gas and chlorinating agent-containing gas are then supplied to the double-walled inlet pipe 22 for injection into the reactor 10 as described above. The remaining reactor post-treatment may be carried out substantially as described above in 106-116, if applicable. In this configuration, a separate supply of protective gas and protective agent tank 102 is not required.

[0039] Figure 7 schematically illustrates another non-limiting example of a plant process configuration 400 in which cooled reactive gas is supplied to a double-walled inlet pipe 22 for use as a protective gas as described above, and at least a portion of the protective gas is recycled gas from the process for reuse as a protective gas. In this non-limiting example, in addition to the supply of fresh / replenishment chlorine to the chlorine tank 104, a recycled supply of chlorine is returned from the gas phase converter 114 to the chlorine tank 104 and recycled via the carbochlorization process. In this example, the recycled chlorine may include Cl2, and / or TiCl4, and / or COCl2, and / or other substances released from the gas phase converter 114. The remainder of processes 104-118 is preferably carried out substantially as described above. In this configuration, separate supplies of protective gas and protective tank 102 are not required.

[0040] Figure 8 schematically illustrates another non-limiting example of plant process configuration 500 in which cooled reactive gas is supplied to a double-walled inlet pipe 22 for use as a protective gas as described above, and at least a portion of the protective gas is recycled gas from the process for reuse as a protective gas. In this non-limiting example, in addition to a new supply of chlorinating agent to the chlorinating agent tank 104, a recycled supply of chlorinating agent is returned from the solid-phase converter 110 to the chlorinating agent tank 104 and recycled via a carbochlorination process. In this example, the recycled chlorinating agent may include Cl2, and / or TiCl4, and / or COCl2, and / or other substances released from the solid-phase converter 110. The remainder of processes 104-118 is preferably carried out substantially as described above. In this configuration, separate supplies of protective gas and protective agent tank 102 are not required.

[0041] Figure 9 schematically illustrates yet another non-limiting example of a plant process configuration 600 in which a cooled reactive gas is supplied to a double-walled inlet pipe 22 for use as a protective gas as described above, and at least a portion of the protective gas is recycled gas from the process for reuse as a protective gas. In this non-limiting example, in addition to the supply of fresh / replenishment chlorine to the chlorine tank 104, a recycled supply of chlorine is returned to the chlorine tank 104 from both the solid-phase converter 110 and the gas-phase converter 114 and recycled through the carbochlorization process. In this example, the recycled chlorine may include Cl2 and / or TiCl4 and / or COCl2. The remainder of processes 104-118 is preferably carried out substantially as described above. In this configuration, separate supplies of protective gas and protective tank 102 are not required.

[0042] Figure 10 schematically shows a non-limiting example of a plant process configuration 700 in which both an inert protective gas and a cooled reactive gas are supplied to the double-walled inlet pipe 22 for use as protective gases, as described above, and at least a portion of the protective gas is recycled gas from the process for reuse as a protective gas. In this non-limiting example, an inert protective gas is supplied from the protective agent tank 102 to the outer pipe 26 of the double-walled inlet pipe 22, and a cooled chlorine agent-containing gas is also supplied from the chlorine agent cooler 118 to the outer pipe 26 of the double-walled inlet pipe 22, thereby supplying a mixture of inert and reactive protective gases to form a protective envelope around the inner end of the double-walled inlet pipe 22, as described above. In addition to the fresh supply of protective gas and chlorinating agent to the respective protective agent tank 102 and chlorinating agent tank 104, a recycled supply of protective agent is provided from the off-gas treatment device 116 to the protective agent tank 102, and a recycled supply of chlorinating agent is provided from both the solid-phase converter 110 and the gas-phase converter 114 back to the chlorinating agent tank 104 for recycling via the carbochlorization process. In this example, the recycled chlorinating agent may include Cl2 and / or TiCl4 and / or COCl2, and the recycled protective agent may include CO and / or CO2. The remainder of processes 104-118 is preferably carried out substantially as described above.

[0043] The plant process configurations in Figures 4 to 10 are provided to illustrate several non-limiting examples of different possible ways of supplying fresh and / or recycled protective gas to one or more of the double-walled inlet pipes 22. However, it is understood that the present invention is not necessarily limited to any one of the plant configurations, but rather may include any number of other configurations that enable the supply of fresh and / or recycled inert and / or reactive protective gases to the double-walled inlet pipes 22 to provide a protective shroud for the gas at the inner end of the double-walled inlet pipes 22 in the reactor 10 during the operation of the carbochlorization process.

[0044] These examples demonstrate that reactors such as fluidized bed reactors, and methods for injecting chlorine-containing gas into reactor vessels according to one or more of the features described herein, can provide improved systems, apparatus, and / or methods for supplying chlorine-containing gas to fluidized bed reactors, reducing mechanical and / or chemical wear and extending the service life of inlet pipes.

Claims

1. A reactor (10) for a carbochlorization process, wherein the reactor is A reactor vessel (12) having an inner wall (18), The protective lining (16) on the inner wall, The reactor vessel is provided with a double-walled inlet pipe (22) for chlorinating agent-containing gas that extends through the protective lining, and the double-walled inlet pipe is Inner pipe (24) and The outer pipe (26) surrounds the inner pipe, Including the peripheral space (28) between the inner pipe and the outer pipe, The chlorinating agent-containing gas can be introduced into the reactor vessel through the end (30) of the inner pipe, and A reactor that allows a protective gas to be introduced into the reactor vessel through the end (32) of the outer pipe in the peripheral space between the inner pipe and the outer pipe.

2. The reactor according to claim 1, wherein the reactor is at least one of a fluidized bed reactor, a circulating fluidized bed reactor, a bubbling bed reactor, a jet bed reactor, a slugging bed reactor, a riser type reactor, a vertical shaft (furnace type) reactor, a moving bed reactor, and a cyclone reactor.

3. The reactor according to claim 1 or 2, wherein the end portion (32) of the outer pipe (26) is coplanar with the inner surface of the protective lining (16) or extends beyond the inner surface of the protective lining into the reactor vessel (12).

4. The reactor according to any one of claims 1 to 3, wherein the end portion (30) of the inner pipe (24) lies on the same plane as the end portion (32) of the outer pipe (26).

5. The reactor according to any one of claims 1 to 3, wherein the end (30) of the inner pipe (24) extends into the reactor vessel (12) beyond the end (32) of the outer pipe (26), or the end of the inner pipe is located in a recessed area within the end of the outer pipe.

6. The reactor according to any one of claims 1 to 5, wherein the peripheral space (28) extends around the entire outer circumference of the end of the inner pipe (24).

7. The reactor, At least one of the following: a second inlet pipe (34) extending into the reactor vessel for injecting titanium raw material into the reactor vessel, a third inlet pipe (36) extending into the reactor vessel for injecting carbon raw material into the reactor vessel, and an exhaust opening (38) at the upper end of the reactor vessel for discharging a gas stream containing titanium tetrachloride from the reactor vessel, Depending on the circumstances, the system may further include a second double-walled inlet pipe (22) for a chlorinating agent-containing gas extending into the reactor vessel through the protective lining, Depending on the circumstances, the first and possibly second double-walled inlet tubes extend into the reactor near the bottom end of the reactor vessel. The reactor according to any one of claims 1 to 6, wherein the protective lining (16) optionally includes a heat-resistant refractory material, and optionally the refractory material includes refractory bricks lining the inner wall of the reactor vessel.

8. A method for injecting a chlorinating agent-containing gas into a reactor vessel (12) of a reactor (10) having a double-walled inlet tube (22) for a carbochlorination process to form titanium tetrachloride from a titanium raw material using a carbonaceous material as a reducing agent, wherein the method involves The chlorinating agent-containing gas is injected into the reactor vessel through the end (30) of the inner pipe (24) of the double-walled inlet pipe, A method comprising simultaneously injecting a protective gas into the reactor vessel through the peripheral space (28) between the inner pipe and the end (32) of the outer pipe (26) of the double-walled inlet pipe.

9. The method according to claim 8, wherein the protective gas forms a protective gas envelope around the end (30) of the inner pipe and the end (32) of the outer pipe, and optionally the chlorinating agent-containing gas comprises a chlorinating agent comprising one or more of chlorine, phosgene (COCl2), carbon tetrachloride (CCL4), thionyl chloride (SOCl2), and / or sulfuryl chloride (SO2Cl2).

10. The method according to claim 8 or 9, wherein the chlorinating agent-containing gas is injected into the reactor vessel at a first rate (Vi), and the protective gas is injected into the reactor vessel at a second rate (Vo), wherein the second rate is equal to or greater than the first rate.

11. The method according to any one of claims 8 to 10, wherein the chlorinating agent-containing gas is injected at a first temperature, and the protective gas is injected at a second temperature, the second temperature being lower than the first temperature.

12. The method according to any one of claims 8 to 11, wherein the protective gas comprises an inert gas, preferably at least one of carbon monoxide (CO), carbon dioxide (CO2), and nitrogen gas (N2).

13. The method according to any one of claims 8 to 12, wherein the protective gas preferably comprises a reactive gas containing at least one of titanium tetrachloride (TiCl4), chlorine gas (Cl2), and carbon tetrachloride (CCl4).

14. The method according to claim 13, wherein the second temperature of the protective gas is at least about 100°C lower than the first temperature of the chlorinating agent-containing gas, and higher than the respective condensation temperatures of the chlorinating agent-containing gas and the protective gas.

15. The method according to any one of claims 8 to 14, wherein the reactor includes the reactor (10) according to any one of claims 1 to 7.

16. The method according to any one of claims 8 to 15, wherein the protective gas is at least partially recycled from another plant process (110, 114, 116) including the carbochlorization process, and / or the protective gas is supplied from a fresh source.

17. The method according to any one of claims 8 to 16, wherein at least a portion of the protective gas comprises a recycled off-gas from the carbochlorization process, and the recycled off-gas preferably comprises at least one of CO2, CO, and mixtures thereof.

18. The method according to any one of claims 8 to 17, wherein at least a portion of the protective gas comprises a recycled chlorinating agent from the carbochlorination process, and the recycled chlorinating agent comprises at least one of Cl2, TiCl4, COCl2, and mixtures thereof.

19. A plant process configuration (100, 200, 300, 400, 500, 600, 700) for forming titanium tetrachloride from a titanium raw material using a carbochlorization process that uses a carbonaceous material as a reducing agent, wherein the plant process configuration includes a reactor according to any one of claims 1 to 7.

20. The plant process configuration according to claim 19, wherein the plant process configuration includes supplying a recyclable protective gas from other processes within the plant process configuration and / or supplying a new protective gas to the double-walled inlet pipe, preferably the supply of the recyclable protective gas includes at least one of a recyclable off-gas, a recyclable chlorinating agent, and a mixture thereof.

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