Arrangement and method for lining long distance pipelines with refractory material

Abstract

The application discloses a kind of long-distance pipeline refractory lining arrangement and construction method, belong to refractory pipeline construction technical field, comprising the following steps: prefabricated segmented step: the pre-installed pipeline is segmented prefabricated, forms several pipe sections;Pipe section reinforcing step: fixed bolt is added in the two ends of each pipe section steel body outside;Castable filling step: in each pipe section installs steel plate lining, then fills refractory castable in pipe section;Once baking step;Refractory brick masonry step: the pipe section that has been treated once baking is carried out working layer refractory brick masonry;Second baking step;Field splicing step: the pipe section that has been baked twice is single-sided beveling using beveling machine, and pad is added under beveling, then hoisting splicing is carried out;Full penetration welding step: full penetration welding is carried out to the pipe section after field splicing.The application can reduce construction difficulty, shorten construction period, and also ensure the quality of construction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high-temperature refractory pipe used in the production of metallurgy, chemical industry, waste incineration and the like, in particular to a long-distance pipe refractory lining arrangement and construction method. BACKGROUND

[0002] The currently recognized carbon reduction technology in the metallurgical industry is the gas-based shaft furnace direct reduction process. Iron ore is charged from the top of the shaft furnace, and the ore is reduced in the furnace. The reduced iron is discharged from the bottom of the furnace. Reducing gas is blown into the furnace from the nozzle in the middle of the furnace body, and escapes from the top of the furnace after reaction. There is a circulating cooling gas at the lower part of the furnace to cool the reduced iron. The inlet and outlet of the furnace body are provided with dynamic sealing devices, which can continuously charge and discharge. The mixture of produced metallic iron and gangue is collectively referred to as direct reduced iron (DRI). Direct reduced iron (DRI) is iron ore reduced to metallic iron under solid state conditions, which can be used as a pure raw material for smelting high-quality and special steel, and can also be used as an iron-containing raw material for casting, ferroalloy, powder metallurgy and other processes. Direct reduction process does not use coke, and raw materials can use cold pressed pellets, pellet blocks or lump ore, and does not use sintered ore, which is a new ironmaking process with high quality, low consumption and low pollution, and is one of the frontiers of steel metallurgy in the world. Its products mainly include: CDRI (pellet-shaped direct reduced iron cooled to ambient temperature), HBI (reduced iron briquettes, which are easy to transport and store after passivation), and HOT DRI produced at 550-750°C and directly charged into an electric furnace for steelmaking.

[0003] The process of direct reduction mainly includes three parts: reduction gas preparation, reduction shaft furnace and waste heat recovery. Among them, ① reduction gas preparation: about 70% of CO+H2 after purification is sent into the mixing chamber under pressure, mixed with equivalent natural gas, sent into the heat exchanger for preheating, and then into the reaction tube with nickel-based catalyst at about 1100°C for catalytic cracking reaction, converted into 4%-36% CO, 60%-70% H2, 3%-6% CH4 and 870°C reduction gas; ② reduction shaft furnace: the cross section is circular, divided into preheating section, reduction section and cooling section; the furnace charge stays in the reduction section above 800°C for 4-6h (total time about 10h), and the operating pressure of the shaft furnace is 0.2-0.3MPa; ③ waste heat recovery: the waste heat of the top gas can be directly recovered to reduce energy consumption and achieve the purpose of energy saving and emission reduction. At the same time, the waste heat recovery system can improve the efficiency of the whole furnace. The top gas is purified and pressurized into the waste heat recovery device, and the recovered waste heat can heat the combustion air and reducing gas through the heat exchanger.

[0004] The development of gas-based direct reduction vertical shaft furnaces has become increasingly sophisticated. Due to the inherent characteristics of the furnace body, which is always vertically erected, the high-temperature (850-1050℃) gas pipelines used for reduction operations need to be configured parallel to the furnace. Because of the high temperature requirements, the pipelines require pre-cast or lining with refractory materials to support and insulate the working gas. However, due to the relatively small diameter (<1.0m) and large length (over 30m) of the pipeline cavity, segmented construction is necessary. In this confined space, ensuring project quality, maintaining construction efficiency, reducing construction difficulty, shortening the construction period, guaranteeing long pipeline service life, and improving safety factors necessitates finding an efficient, reliable, and scientific construction method to guarantee project quality. Summary of the Invention

[0005] The purpose of this invention is to provide a method for arranging and constructing refractory linings for long-distance pipelines, which can reduce construction difficulty, shorten the construction period, ensure construction quality, and ensure that the equipment functions meet the process technology design requirements.

[0006] To achieve the above objectives, the present invention provides a method for arranging and constructing refractory linings for long-distance pipelines, comprising the following steps:

[0007] Prefabrication segmentation process: The pre-installed pipeline is prefabricated into segments to form several pipe sections;

[0008] Pipe section reinforcement steps: Install fixing bolts on the outside of the steel body at both ends of each pipe section;

[0009] Refractory filling steps: Install steel plate lining in each pipe section, and then fill the pipe section with refractory castable;

[0010] One baking step: The pipe section filled with refractory is baked once according to the baking regime;

[0011] Refractory bricklaying steps: Lay the working layer of refractory bricks on the pipe section that has undergone one baking treatment.

[0012] Secondary baking step: The completed pipe section is then baked a second time;

[0013] On-site splicing steps: The pipe section that has undergone secondary baking is beveled on one side using a beveling machine, and a pad is installed under the bevel before hoisting and splicing.

[0014] Full penetration welding procedure: Perform full penetration welding on the pipe sections after they are spliced ​​on site.

[0015] Furthermore, in the prefabrication segmentation step, the length of the pipe segment is 6m.

[0016] Furthermore, the filling step of the castable material specifically includes: installing steel plate linings on the inner side of the steel cylinder wall of each pipe section and at the joint.

[0017] Furthermore, in the filling step of the castable, the refractory castable includes an insulation layer castable and a permanent layer castable.

[0018] Furthermore, the on-site splicing step specifically includes: using a beveling machine to grind a V-shaped bevel around the steel cylinder of each pipe section, wherein the angle of the V-shaped bevel is 45-60°.

[0019] Furthermore, in the full penetration welding step, different welding rods are used for welding according to the steel material of different pipe sections.

[0020] Furthermore, when the steel material of the pipe section to be welded is Q235B, J422 welding rods are used for welding; when the steel material of the pipe section to be welded is Q345B, J506 welding rods are used for welding.

[0021] Furthermore, when the steel material of the pipe section to be welded is Q345B, the welding using J506 welding rod includes: first, preheating the J506 welding rod to 300°C and holding it at that temperature for 2 hours, then performing carbon dioxide shielded welding, and finally performing face welding using shielded metal arc welding or submerged arc welding.

[0022] Furthermore, in the full penetration welding step, the full penetration welding method adopts one or more of the following: shielded metal arc welding (SMAW), submerged arc welding (SAW), gas tungsten inert welding (GTAW), and gas metal arc welding (GMAW).

[0023] Furthermore, the on-site splicing step also includes: after the bevel is manufactured, cleaning the bevel and performing visual and non-destructive testing.

[0024] Compared with existing technologies, the method for arranging and constructing refractory linings for long-distance pipelines according to the present invention involves prefabricating pipelines in sections, bolting each section, installing a steel plate lining in each section, and then filling the sections with refractory castable. This technical solution also includes two baking processes, followed by single-sided beveling of the baked sections using a beveling machine, with a backing plate installed under the beveling, and then full-penetration welding of the assembled sections. By adopting full-penetration welding, the construction period for a 100m long high-temperature gas pipeline can be shortened to less than 50 days, which has significant implications for promoting the application of high-temperature, small-diameter refractory-lined gas pipelines in industries such as gas-based direct reduced iron, COREX furnaces, waste incinerators, and petrochemicals. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of full penetration welding for the arrangement and construction method of the refractory lining of long-distance pipelines according to the present invention;

[0026] Figure 2 is a single-side bevel angle diagram of the present application;

[0027] Figure 3 is a dogleg diagram of the arrangement and construction method of long-distance pipeline refractory lining of the present application;

[0028] Figure 4 is a segmented diagram of the arrangement and construction method of long-distance pipeline refractory lining of the present application;

[0029] Figure 5 is a segmented pipeline diagram containing brick support plates of the arrangement and construction method of long-distance pipeline refractory lining of the present application;

[0030] Figure 6 is a conventional segmented steel cylinder diagram of the arrangement and construction method of long-distance pipeline refractory lining of the present application;

[0031] Figure 7 is a refractory lining band sealing staggered full penetration welding diagram of the arrangement and construction method of long-distance pipeline refractory lining of the present application;

[0032] Figure 8 is a 5mm mortar jointing full penetration welding diagram of the arrangement and construction method of long-distance pipeline refractory lining of the present application;

[0033] Figure 9 is a refractory lining pipe diagram after full penetration welding jointing of the arrangement and construction method of long-distance pipeline refractory lining of the present application;

[0034] Figures 10 to 13 is a COREX furnace molten gas pipeline full penetration welding diagram and related pipeline structure diagram of the arrangement and construction method of long-distance pipeline refractory lining of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] The terms "first", "second", "third", "fourth" and the like in the description and in the claims of the present application, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of these terms herein is to be construed to cover the embodiments of the application whether or not the embodiments are described with the use of these terms.

[0037] It should be understood that, in various embodiments of the present application, the magnitude of the serial number of each process does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0038] It should be understood that in the present application, "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not necessarily limit to the clearly listed steps or units, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0039] It should be understood that in the present application, "a plurality of" means two or more. "And / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist together, and B exists alone. The character " / " generally represents that the front and rear associated objects are in an "or" relationship. "Including A, B and C", "including A, B, C" means that A, B and C are all included, "including A, B or C" means that one of A, B and C is included, and "including A, B and / or C" means that any one or any two or three of A, B and C is included.

[0040] It should be understood that in the present application, "B corresponding to A", "B corresponding to A", "A corresponding to B" or "B corresponding to A" means that B is associated with A, and B can be determined according to A. Determining B according to A does not mean that B is determined only according to A, but B can also be determined according to A and / or other information. The matching of A and B means that the similarity of A and B is greater than or equal to a preset threshold.

[0041] Depending on the context, "if" as used herein can be interpreted as "when" or "while" or "in response to determining" or "in response to detecting".

[0042] The technical solutions of the present application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in some embodiments.

[0043] In the present construction operation, for the larger diameter refractory pipe, the human body can be accommodated, and the internal lining construction is generally adopted by supporting the support frame in the pipe after the steel is processed and manufactured, and then pouring or laying bricks. This not only ensures the integrity of the equipment, but also ensures the stability of the working layer. The gas-based shaft furnace high-temperature pipe has a small inner diameter and adopts a three-layer structure (insulation layer castable, permanent layer castable, working surface brick), and the length exceeds 100 m, and there is a shrimp bend structure, so it cannot meet the construction methods of manual work, formwork, formwork removal, and machinery. Even if it can be installed, there are huge safety hazards in the narrow and closed limited space operation, and it cannot meet the construction period requirements.

[0044] In order to ensure the design requirements of engineering quality and meet the engineering requirements, a long-distance pipe refractory lining arrangement and construction method is proposed, as shown in Figure 1 The long-distance pipe refractory lining arrangement and construction method according to the preferred embodiment of the present application comprises the following steps:

[0045] The prefabricated segmented step: the pre-installed pipe is segmented and prefabricated to form a plurality of pipe segments;

[0046] The pipe segment reinforcing step: fixed bolts are installed on the outside of the steel body at both ends of each pipe segment;

[0047] The castable filling step: a steel plate lining is installed in each pipe segment, and then refractory castable is filled in the pipe segment;

[0048] The first baking step: the pipe segment filled with castable is subjected to a first baking treatment according to the baking system;

[0049] The refractory brick laying step: the pipe segment subjected to the first baking treatment is subjected to refractory brick laying of the working layer;

[0050] The second baking step: the pipe segment after laying is subjected to a second baking;

[0051] The on-site splicing step: the pipe segment subjected to the second baking is subjected to single-sided beveling by a beveling machine, a backing plate is installed under the beveling, and then hoisting and splicing are performed;

[0052] The full penetration welding step: the pipe segment after on-site splicing is subjected to full penetration welding.

[0053] The embodiment of the present application adopts the segmented construction of the pipe and the full penetration welding splicing of the external steel body to realize it. That is, the long-distance pipe is divided into natural segments for easy implementation without opening or installing other equipment, and the length of each pipe segment is about 6 m. Fixed bolts are installed on the outside of the steel body at both ends of each natural segment or shrimp bend segment for centering and reinforcing during splicing.

[0054] In an embodiment of the present application, the step of filling the castable material specifically comprises: installing a steel plate lining on the inner side of the steel cylinder wall of each pipe segment and the joint part.

[0055] In an embodiment of the present application, in the step of filling the castable material, the refractory castable material comprises a heat-insulating layer castable material and a permanent layer castable material.

[0056] In an embodiment of the present application, the step of field splicing specifically comprises: using a beveling machine to grind a V-shaped bevel on one turn of the steel cylinder of each pipe segment, the angle of the V-shaped bevel being 45-60°, as shown in Figure 2

[0057] No matter which one of the four common welding methods, such as shielded metal arc welding (SMAW), submerged arc welding (SAW), gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW), is used for full penetration welding, it needs to be combined with the specific steel cylinder material and working condition requirements, and the full penetration welding is an equal strength weld, which uses equal strength of the joint and base material. In an embodiment of the present application, in the step of full penetration welding, different electrodes are used for welding corresponding to different steel material of the pipe segment. If deep penetration welding is used, special electrodes are used to obtain welding with large penetration depth. When welding cutting operation is performed, a gas cylinder conforming to the requirements of the relevant national standards and regulations should be used first, and the safety operation regulations should be strictly followed in the storage, transportation and use of the gas cylinder. The pipeline conveying flammable gas and combustion-supporting gas should be installed, used and managed according to the regulations, and the operators and inspectors should be specially trained in safety technology.

[0058] In an embodiment of the present application, when the steel material of the welded pipe segment is Q235B, J422 electrode is used for welding; when the steel material of the welded pipe segment is Q345B, J506 electrode is used for welding. When the steel material of the welded pipe segment is Q345B, the use of J506 electrode for welding comprises: first, preheating the J506 electrode to 300℃ and keeping for 2 hours, then performing carbon dioxide shielded welding, and finally performing face welding by shielded metal arc welding or submerged arc welding.

[0059] In an embodiment of the present application, in the step of full penetration welding, the full penetration welding method uses one or more of shielded metal arc welding (SMAW), submerged arc welding (SAW), gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW).

[0060] In an embodiment of the present application, the step of field splicing further comprises: after the beveling is completed, cleaning the bevel, and performing appearance and non-destructive testing, and if the flaw detection is unqualified, the pipe segment needs to be removed and re-welded until the flaw detection is qualified.

[0061] According to Figures 1 to 6 ​As shown, in an embodiment of the present application, for the steel cylinder with small diameter and refractory lining pipe, the construction is basically carried out on site and divided into multiple groups for simultaneous construction. According to the actual pipe working conditions, the pipe is cut and segmented to avoid special positions such as brick support plate position, temperature measurement hole position, observation hole position, etc. After the refractory filling construction is completed, full penetration welding is carried out. After the pouring of the thermal insulation layer and the permanent layer of the castable is completed, drying treatment is carried out according to the baking system. After baking, the refractory brick masonry of the working layer is carried out. After the masonry is completed, secondary baking is carried out. The next step is the important splicing process. In the on-site welding process, a beveling machine is used for single-sided beveling, and a backing plate is added under the bevel. After beveling, the slag, oil stains, dust, rust, etc. on the bevel are cleaned.

[0062] After the design of the arrangement and construction method of the long-distance pipe refractory lining of the present application, according to the working conditions and gas-based direct reduction process requirements, for the long-distance, small-diameter, long-life, internally lined refractory lining high-temperature gas pipe, two forms are used for full penetration welding, such as Figure 7 and Figure 8 As shown, one is to pour the lining refractory, and a butt joint misalignment step is left during masonry, which facilitates centering splicing and high-temperature gas sealing. The other is flat butt joint. Regardless of which welding is used, 5mm mortar joint and external body bolt are left for centering welding, steel body lining, and full V-shaped groove. If full penetration welding is not used, the construction period of a 100m long high-temperature gas pipe requires more than 80 days. After using this method, the construction period can be shortened to within 50 days, which includes two baking, flaw detection and acceptance, hoisting and splicing. It has good promotion significance for the high-temperature small-diameter refractory lining gas pipe in the gas-based direct reduction iron, COREX furnace, waste incineration furnace, petrochemical industry, etc.

[0063] In an embodiment of the present application, the arrangement and construction method of the long-distance pipe refractory lining of the present application has been implemented and applied in the high-temperature gas pipe of the largest direct reduction iron production process in China. The entire pipe is more than 100m long, divided into 23 segments for construction, with a construction period of 52 days, as shown in Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 9 .

[0064] In an embodiment of the present application, the arrangement and construction method of the long-distance pipe refractory lining of the present application has been implemented and applied in the high-temperature gas pipe of the largest direct reduction iron production process in China. The entire pipe is more than 100m long, divided into 23 segments for construction, with a construction period of 52 days, as shown in Figures 10 to 13 .

[0065] The arrangement and construction method of long-distance pipeline refractory lining according to the application carries out sectional prefabrication to the pipeline, carries out bolt reinforcement to each pipe section, installs a steel plate lining in each pipe section, then fills the pipe section with refractory castable; the technical solution further comprises twice baking, uses a beveling machine to single-face bevel the pipe section after the second baking, installs a backing plate under the bevel, and carries out full penetration welding to the pipe section after on-site splicing. The technical solution can reduce construction difficulty, shorten construction period, ensure construction quality, and ensure that the equipment function meets the process technology design requirement. The technical solution has good popularization and assistance significance for the high-temperature small-diameter gas pipeline with refractory lining in the gas-based direct reduction iron, COREX furnace, waste incineration furnace, petrochemical and other industries.

[0066] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application and to allow others skilled in the art to understand the application for various exemplary embodiments with various modifications being applicable. The scope of the application is intended to be defined by the claims and their equivalents.

Claims

1. A method of construction of an arrangement of long distance pipeline lining material, characterised in that, The method comprises the following steps: a prefabrication and segmentation step of segmenting and prefabricating a pre-installed pipeline to form a plurality of pipe segments; a pipe segment reinforcement step of installing fixing bolts outside the steel body at both ends of each pipe segment; a refractory filler filling step of installing a steel plate lining inside the steel body cylinder wall of each pipe segment and at the joint, and then filling the pipe segment with refractory castable; when filling the refractory castable, the refractory castable at one joint of two adjacent pipe segments is recessed inward, and the refractory castable at the joint of the other pipe segment is protruded outward; and an abutting sealing chamfer and a mortar joint are formed between the refractory castable at the joint of the two pipe segments; a first baking step of baking the pipe segment filled with the refractory castable according to a baking schedule; a refractory brick masonry step of masonry of the refractory brick of the working layer of the pipe segment subjected to the first baking; a second baking step of baking the pipe segment subjected to the masonry; a field jointing step of single-sided beveling of the pipe segment subjected to the second baking by using a beveling machine, installing a backing plate under the bevel, and then hoisting and jointing; a full penetration welding step of full penetration welding of the pipe segment subjected to the field jointing.

2. The method of construction of an arrangement of long distance pipeline refractory lining according to claim 1, characterised in that, In the prefabrication and segmentation step, the length of the pipe segment is 6 m.

3. The method of construction of an arrangement of long distance pipeline refractory lining according to claim 1, characterised in that, In the refractory filler filling step, the refractory castable comprises a thermal insulation layer castable and a permanent layer castable.

4. The method of construction of an arrangement of long distance pipeline refractory lining according to claim 1, characterised in that, The field jointing step specifically comprises: grinding a V-shaped bevel by using a beveling machine at one turn of the steel cylinder of each pipe segment, and the angle of the V-shaped bevel is 45-60°.

5. The method of construction of an arrangement of long distance pipeline linings according to claim 1, characterised in that, In the full penetration welding step, different electrodes are used for welding corresponding to different steel body materials of the pipe segment.

6. The method of construction of an arrangement of long distance pipeline refractory lining according to claim 5, characterised in that, When the steel body material of the welded pipe segment is Q235B, J422 electrode is used for welding; when the steel body material of the welded pipe segment is Q345B, J506 electrode is used for welding.

7. A method of construction of a long distance pipelining refractory lining arrangement according to claim 6, characterised in that, When the steel body material of the welded pipe segment is Q345B, the J506 electrode welding comprises: firstly, preheating the J506 electrode to 300℃ and keeping for 2 hours, then performing carbon dioxide shielded welding, and finally performing surface welding by using electrode arc welding or submerged arc welding.

8. The method of construction of the arrangement of long distance pipeline refractory lining according to claim 1, characterized by, In the full penetration welding step, the full penetration welding mode uses one or more of the following: electrode arc welding (SMAW), submerged arc welding (SAW), tungsten inert gas welding (GTAW) and gas metal arc welding (GMAW).

9. The method of construction of the arrangement of long distance pipeline refractory lining according to claim 1, characterized in that, The field jointing step further comprises: cleaning the bevel after the bevel is manufactured, and performing appearance and non-destructive testing.

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