Three-way junction structure of updraft gas pipeline of COREX melting gasifier

Abstract

The application discloses a three-way joint structure of an updraft gas pipeline of a COREX melting gasifier and belongs to the technical field of metallurgical refractory materials. The three-way joint structure comprises a first pipeline section, a second pipeline section and a third pipeline section. The first pipeline section is located at the top of the updraft gas pipeline and adopts a vaulted structure. The second pipeline section is located around the updraft gas pipeline, adopts a thermal insulation layer as a bottom layer and adopts refractory bricks as working face bricks. The third pipeline section is configured as a bent structure and comprises special-shaped structure bricks and pipeline bricks which are spliced with each other. The three-way joint structure of the updraft gas pipeline can improve the bearing capacity of the pipeline and prolong the service life of the three-way joint of the gas pipeline by combining lightweight refractory castable and refractory clay bricks, thereby providing protection for the safe production of enterprises and providing guarantee for the generation and use of high-proportion gas.

Description

Technical Field

[0001] This invention belongs to the technical field of refractory materials for metallurgy, and in particular relates to a three-way structure for the rising gas pipeline of a COREX molten gasification furnace. Background Technology

[0002] The COREX process, also known as the molten reduction ironmaking process, is a new ironmaking production method that has matured in recent years. It can not only use non-coking coal to directly produce iron, but also has a short process flow, low investment, low production cost, less pollution, and the quality of the produced molten iron is comparable to that of blast furnace iron. It can also use the discharged process gas to produce sponge iron in a vertical shaft furnace, replacing high-quality scrap steel for electric arc furnace steelmaking.

[0003] COREX molten reduction ironmaking technology is a non-blast furnace ironmaking technology designed to reduce reliance on coking coal resources. Its process is characterized by the following: raw materials (pellets, sinter, flux, etc.) enter the reduction shaft furnace, where they are preheated and pre-reduced by the reducing gas inside the furnace. The preheated material is then fed into the gasifier, where, under oxygen-based smelting conditions, final reduction, melting, and removal of impurities from the molten iron are achieved, ultimately producing molten iron and gas. The gas, after being scavenged by a hot cyclone separator, is then fed back into the reduction shaft furnace as reducing gas. The top gas produced in the shaft furnace is decarburized and purified before being injected into the gasifier tuyeres, thus achieving a self-circulating gas flow process. The COREX process flow is shown below. Figure 1 .

[0004] To increase the proportion of non-coking coal used to over 60%, the gasifier dome has been enlarged to increase gas production capacity, reduce overall iron production costs, and ensure the supply of reducing gas for the pre-reduction and smelting zones of the vertical shaft furnace. Based on the characteristics of COREX smelting, the raw material structure was designed to expand the adaptability of raw materials, and a creative process for pulverized coal injection into the gasifier dome was developed, solving the problem of clean and efficient use of non-coking coal. High-concentration metallurgical gas recycling improves the utilization rate of COREX furnace top gas. However, the large amount of gas generated, the high temperature (1100℃), high pressure (0.35MPa), and high dust concentration of the gas flow pose challenges to the refractory materials used in the gas pipelines, especially in the three-way junction area of ​​the gas riser pipe. These materials, in terms of structure, strength, and erosion resistance, cannot meet the requirements of the improved process. This area has a swirling zone; while the original coating was easy to apply and reduced implementation difficulty, its low resistance to erosion and scour led to severe coating peeling and a service life of less than two years. Frequent replacements in a short period affected production and created safety hazards. Therefore, finding a new refractory structure to improve its strength, ensure stable and smooth process operation, and enable long-term reliable operation has become the key to solving the problem. Summary of the Invention

[0005] The purpose of this invention is to provide a three-way structure for the rising gas pipeline of a COREX molten gasifier, which can improve the load-bearing capacity of the pipeline, extend the service life of the three-way junction of the COREX molten gasifier's generating gas pipeline, safeguard the safe production of enterprises, and provide a guarantee for the generation and use of high-proportion gas.

[0006] To achieve the above objectives, the present invention provides a three-way structure for the rising gas pipeline of a COREX molten gasifier, comprising a first pipeline section, a second pipeline section, and a third pipeline section. The first pipeline section is located at the top of the rising gas pipeline and adopts an arched structure. The second pipeline section is located around the rising gas pipeline, and adopts an insulation layer as the bottom layer and refractory bricks as the working surface bricks. The third pipeline section is configured with a curved structure and includes interlocking irregularly shaped structural bricks and pipeline bricks.

[0007] Furthermore, the refractory bricks in the second pipe section are spliced ​​and fixed using a snap-fit ​​method.

[0008] Furthermore, the refractory brick has at least one protruding structure and at least one groove structure respectively provided on the interlocking parts.

[0009] Furthermore, the second pipeline section is connected to a thermal cyclone dust collector. The upper part of the pipeline in the direction of the gas flow and the thermal cyclone dust collector is constructed by first pouring lightweight refractory castable and then laying refractory clay bricks.

[0010] Furthermore, the lightweight refractory castable includes Al2O3, Fe2O3, SiO2, and CaO, and the linear change rate of the lightweight refractory castable reaches -1.0 to 0% at 1400℃.

[0011] Furthermore, the refractory clay brick comprises Al₂O₃ and Fe₂O₃, and the linear variation rate of the refractory clay brick reaches -0.1 to +0.1% at 1400℃*2h.

[0012] Furthermore, the second pipeline section is surrounded by an external steel cylinder structure.

[0013] Furthermore, the thickness of the refractory bricks in the second pipe section is 230 mm or more.

[0014] Furthermore, a manhole is connected in the vertical direction of the second pipe section. The manhole includes a lightweight refractory castable layer, a refractory clay brick layer, and a heat-insulating brick layer arranged in sequence. The heat-insulating brick layer includes Al2O3 and Fe2O3, and the linear change rate of the heat-insulating brick layer reaches -1.0 to 0% at 1300℃*12h.

[0015] Furthermore, the top bricks of the first pipe section are designed with grooved joints.

[0016] Compared with existing technologies, the three-way structure of the rising gas pipeline of the COREX molten gasifier according to the present invention, wherein the second pipeline section uses an insulation layer as the bottom layer and refractory bricks as the working face bricks, and the upper part of the pipeline in the direction of gas flow and the hot cyclone dust collector is constructed by first casting lightweight refractory castable and then laying refractory clay bricks. The third pipeline section includes interlocking irregularly shaped structural bricks and pipeline bricks. Based on existing process conditions, the present invention uses a combined brick structure of lightweight refractory castable and high-strength refractory clay bricks, which not only improves the load-bearing capacity of the pipeline but also extends its service life. A grooved joint design is used between the top bricks of the first pipeline section to ensure the bonding strength of the bricks.

[0017] In addition, in the prior art, the refractory material at the manhole is prone to falling off, which can cause the outer steel plate to glow red-hot, posing a safety hazard. This invention, while verifying the dimensions, makes the manhole structure composed of the lightweight refractory refractory layer, the refractory clay brick layer, and the heat insulation brick layer arranged in sequence. It optimizes the composite brick structure and uses patterned brick splicing to ensure that there is no air leakage and no fire spread.

[0018] Through the brick type and structural design of this invention, not only is the service life of the three-way junction of the gas generation pipeline of the COREX melting furnace increased from the original 2 years to 8 years, but it also safeguards the safe production of enterprises and provides a guarantee for the generation and use of high proportion of gas. Attached Figure Description

[0019] Figure 1 This is a flow chart of the existing COREX process.

[0020] Figure 2 This is a schematic diagram of the three-way structure of the rising gas pipeline of the COREX molten gasifier of the present invention;

[0021] Figure 3 This is a schematic diagram of the part of the three-way structure of the rising gas pipeline of the COREX molten gasifier that often needs to be replaced in the existing technology;

[0022] Figure 4 This is a schematic diagram of the composite bricks in the three-way structure of the rising gas pipeline of the COREX melting gasifier of the present invention.

[0023] Figure 5 This is a schematic diagram of the composite brick for the manhole in this invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0026] It should be understood that in the various embodiments of the present invention, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0027] It should be understood that in this invention, "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0028] It should be understood that in this invention, "multiple" refers to two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, "and / or B" can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "Contains A, B, and C", "Contains A, B, and C" means that all three A, B, and C are contained; "Contains A, B, or C" means that one of A, B, and C is contained; "Contains A, B, and / or C" means that any one, two, or three of A, B, and C are contained.

[0029] It should be understood that in this invention, "B corresponding to A", "B corresponding to A", "A and B correspond", or "B and A correspond" means that B is associated with A, and B can be determined based on A. Determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information. Matching A and B is defined as a similarity between A and B that is greater than or equal to a preset threshold.

[0030] Depending on the context, "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection."

[0031] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0032] Figure 2 The diagram shows a three-way structure of the rising gas pipeline of a COREX molten gasifier according to a preferred embodiment of the present invention. The structure includes a first pipeline section, a second pipeline section, and a third pipeline section. The first pipeline section is located at the top of the rising gas pipeline and adopts an arched structure. The second pipeline section is located around the rising gas pipeline, using an insulation layer as the bottom layer and refractory bricks as the working surface bricks. The third pipeline section is configured with a curved structure and includes interlocking irregularly shaped structural bricks and pipeline bricks. In this embodiment, the high-temperature gas generated by pulverized coal injection in the COREX molten gasifier is sent through a gas pipeline to the three-way junction of the gas pipeline before the hot cyclone dust collector. The refractory structure of the three-way junction is adjusted and redesigned. On the one hand, low-iron raw materials are selected based on the gas composition (as shown in Table 1 below).

[0033]

[0034] The coal gas contains CO and H2 components with high reducing potential. At high temperatures, hydrogen readily reacts with Fe2O3 in the refractory material, thereby reducing the strength and stability of the refractory material. Simultaneously, the high-velocity, high-flow-rate gas carrying dust can also easily react chemically with the refractory material, leading to a reduction in its lifespan. Furthermore, the scouring and swirling action can cause the refractory material to detach. Figure 3 The area circled in the middle indicates the parts that frequently require replacement. Therefore, to extend the service life of the refractory material and improve its resistance to erosion, the refractory material and structural form must be changed. The existing castable method is replaced with a lightweight castable as the insulation layer and stronger refractory bricks as the working face bricks. The brick structure is designed and installed with precise joints. While maintaining the external steel cylinder structure, the brick thickness is increased by 30mm, and the internal diameter of the pipe is reduced, thereby increasing strength and the working face thickness.

[0035] 5. In one embodiment of the present invention, the refractory bricks in the second pipe section are spliced ​​and fixed using a snap-fit ​​method. The snap-fit ​​on the refractory brick is provided with at least one protruding structure and at least one groove structure to ensure the axial load-bearing strength of the refractory brick.

[0036] In one embodiment of the present invention, the second pipe section is connected to a thermal cyclone dust collector, where the coal gas flow and the thermal cyclone...

[0037] The upper part of the duct in the direction of the dust collector is constructed by first pouring lightweight refractory castable and then laying refractory clay bricks. The bottom layer of the third duct section also uses lightweight refractory castable. The irregularly shaped structural bricks and pipe bricks of the third duct section are all...

[0038] Refractory clay bricks are used.

[0039] In one embodiment of the present invention, the lightweight refractory castable includes Al2O3, Fe2O3, SiO2, and CaO, and the linear change rate of the lightweight refractory castable reaches -1.0% to 0% at 1400°C. The lightweight refractory castable in this invention...

[0040] The physicochemical properties of the material are shown in the table below: 15

[0041]

[0042] In one embodiment of the present invention, the refractory clay brick comprises Al₂O₃ and Fe₂O₃, and the linear variation rate of the refractory clay brick reaches -0.1% to +0.1% at 1400℃ for 2 hours. The physicochemical properties of the refractory clay brick in the present invention are shown in the table below:

[0043]

[0044] The third pipe section is configured with a curved structure, also known as a "shrimp bend" structure. This section comprises interlocking irregularly shaped structural bricks and pipe bricks. For the shrimp bend, bricks are cut and laid on-site using traditional bricklaying techniques to ensure the support strength and load-bearing capacity of the bend. The lower part of the shrimp bend incorporates irregularly shaped structural bricks that work in conjunction with the pipe bricks, further enhancing the support strength for the upper part.

[0045] Figure 4 This is a schematic diagram of the composite bricks in the three-way structure of the rising gas pipeline of the COREX molten gasifier of the present invention, wherein the dimensional parameters of the composite bricks in each part of the three-way structure are as follows: Figure 4 As shown, while keeping the external steel cylinder structure unchanged, the thickness of the bricks around the rising gas pipeline is increased by 30mm, which improves the strength of the pipeline and the thickness of the working surface.

[0046] In one embodiment of the present invention, an external steel cylinder structure is arranged around the second pipe section, and the thickness of the refractory bricks of the second pipe section is 230mm or more.

[0047] Figure 5This is a schematic diagram of the composite brick structure for a manhole in this invention. In one embodiment, a manhole is connected vertically to the second pipe section. The manhole includes a lightweight refractory castable layer, a refractory clay brick layer, and a heat-insulating brick layer arranged sequentially. The heat-insulating brick layer includes Al2O3 and Fe2O3. The linear change rate of the heat-insulating brick layer reaches -1.0 to 0% at 1300℃*12h. The physicochemical properties of the heat-insulating brick layer are shown in the table below.

[0048]

[0049]

[0050] In one embodiment of the present invention, the top bricks of the first pipe section are designed with groove joints to further ensure the bonding ability of the bricks.

[0051] Addressing the issue of short refractory material lifespan and severe erosion at the three-way junction, observation hole, and manhole of the gasification pipeline in the COREX smelting process gasifier, this invention, based on existing process conditions, completely replaces all refractory materials with high-strength clay brick structures. Particularly, it optimizes the design of the bends, using irregularly shaped bricks to complement the pipe bricks, thus improving both load-bearing capacity and service life. The top bricks of the gas pipeline employ a grooved joint design to ensure strong bonding. Previously, the refractory material at the manhole was prone to detachment, causing the external steel plate to glow red-hot, posing a safety hazard. While verifying dimensions, the brick structure was optimized, using patterned brick splicing to ensure no gas leakage and no fire spread. Through the brick type and structural design of this invention, the service life of the three-way junction of the COREX smelting furnace gasification pipeline is increased from 2 years to 8 years, safeguarding the company's safe production and ensuring the generation and use of high-proportion gas.

[0052] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A three-way junction structure for the rising gas pipeline of a COREX molten gasifier, characterized in that, The system includes a first pipeline section, a second pipeline section, and a third pipeline section. The first pipeline section is located at the top of the rising gas pipeline and adopts an arched structure. The top bricks of the first pipeline section are designed with grooved joints. The second pipeline section is located around the rising gas pipeline and uses an insulation layer as the bottom layer and refractory clay bricks as the working surface bricks. The third pipeline section is configured with a curved structure and includes interlocking irregularly shaped structural bricks and pipeline bricks. The refractory clay bricks in the second pipeline section are spliced ​​and fixed using a snap-fit ​​method; The interlocking mechanism on the refractory clay brick is provided with at least one protruding structure and at least one groove structure respectively. The second pipeline section is connected to a thermal cyclone dust collector. The upper part of the pipeline in the direction of the gas flow and the thermal cyclone dust collector is constructed by first casting lightweight refractory castable and then laying refractory clay bricks. The lightweight refractory castable comprises Al2O3, Fe2O3, SiO2, and CaO, and its linear change rate is 1400℃. The temperature dropped to -1.0% to 0% within 24 hours. The refractory clay bricks comprise Al2O3 and Fe2O3, and the linear change rate of the refractory clay bricks is 1400℃. The value reached -0.1% to +0.1% over 2 hours.

2. The three-way structure of the rising gas pipeline of the COREX molten gasifier according to claim 1, characterized in that, The second pipeline section is surrounded by an external steel cylinder structure.

3. The three-way structure of the rising gas pipeline of the COREX molten gasifier according to claim 1, characterized in that, The thickness of the refractory clay bricks in the second pipeline section is 230mm or more.

4. The three-way structure of the rising gas pipeline of the COREX molten gasifier according to claim 1, characterized in that, A manhole is connected vertically to the second pipe section. The manhole comprises a lightweight refractory castable layer, a refractory clay brick layer, and an insulating brick layer arranged sequentially. The insulating brick layer comprises Al2O3 and Fe2O3, and the linear change rate of the insulating brick layer is 1300℃. The value reached -1.0 to 0% within 12 hours.

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