Novel furnace cover suitable for carbonization furnace

Abstract

The utility model relates to the field of electric furnaces, in particular to a novel furnace cover suitable for a carbide furnace, which comprises a central furnace cover and an edge furnace cover, the central furnace cover and the edge furnace cover are of a densely-arranged pipe type structure and are formed by densely arranging parallel seamless steel pipes; the central furnace cover is mechanically connected with the edge furnace cover; and the central furnace cover and the edge furnace covers are made of stainless steel. The service life of the novel furnace cover feeding line is more than 7 times longer than that of an original furnace cover, continuous and stable operation of a carbonization furnace is guaranteed, effective support is provided for various technical and economic indexes needed by industrial construction, and stable promotion of industrial construction work is facilitated.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of electric furnace, concretely relates to a novel furnace cover suitable for carbonization furnace. BACKGROUND

[0002] Through continuous process practice and exploration, a new high-efficiency smelting mode in the furnace is currently researched, which greatly increases smelting power, shortens smelting period, and realizes low-cost high-efficiency smelting mode. But the traditional metallurgical equipment and the new process of carbonization furnace are seriously mismatched. The key equipment of the carbonization furnace such as the water-cooled furnace cover has a high frequency of water leakage under the working condition of closed high temperature and high pressure for a long time, and the service life is extremely short, which restricts the stability and continuity of the carbonization furnace smelting. Because the furnace cover is long-term heated by high temperature radiation, the material changes, water leakage occurs, and the production is seriously affected. SUMMARY

[0003] In view of the defects of the prior art, the utility model provides a novel furnace cover suitable for carbonization furnace, solves the problem of abnormal water leakage and short service life of the furnace cover, and prolongs the service life of the furnace cover.

[0004] The utility model provides a novel furnace cover suitable for carbonization furnace, which comprises a center furnace cover and an edge furnace cover.

[0005] The center furnace cover and the edge furnace cover are densely arranged pipe type structures composed of parallel seamless steel pipes.

[0006] The center furnace cover and the edge furnace cover are mechanically connected.

[0007] The material of the center furnace cover and the edge furnace cover is stainless steel.

[0008] In some embodiments, the center furnace cover is composed of three identical furnace covers.

[0009] In some embodiments, the edge furnace cover is composed of six identical furnace covers.

[0010] In some embodiments, the inside of the seamless steel pipe is filled with cooling medium.

[0011] In some embodiments, the parallel seamless steel pipes are welded.

[0012] In some embodiments, the pipe way of the seamless steel pipe is connected by a flexible elbow.

[0013] In some embodiments, the outer diameter of the seamless steel pipe ranges from 80 to 90 mm, and the inner diameter ranges from 50 to 60 mm.

[0014] In some embodiments, the stainless steel comprises 316L.

[0015] In some embodiments, the edge furnace cover comprises multiple groups of water inlet and return water inlets, and the water inlets and return water inlets are arranged adjacently.

[0016] In some embodiments, the water volume of the center furnace cover ranges from 30 to 40 cubic meters per hour.

[0017] The utility model discloses the beneficial effect that:

[0018] The utility model discloses a center furnace cover and edge furnace cover, the center furnace cover and edge furnace cover are dense -arranged pipe type structure, and the seamless steel pipe of parallel dense arrangement, the center furnace cover and edge furnace cover mechanical connection, the material of center furnace cover and edge furnace cover is stainless steel.

[0019] The novel furnace cover of the utility model is more than 7 times the service life of the original furnace cover, which not only ensures the continuous and stable operation of the carbonization furnace, but also provides effective support for various technologies and economic indicators required for industrialization construction, and is conducive to the steady progress of industrialization construction work. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to better understand the utility model, reference can be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily drawn to scale, and related elements can be omitted, or in some cases the scale can have been exaggerated in order to emphasize and clearly show the novel features described herein. In addition, system components can be arranged differently as known in the art. Furthermore, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0021] Figure 1 A reference schematic diagram of a novel furnace cover suitable for a carbonization furnace of the utility model is shown;

[0022] Figure 2 A front view of a center furnace cover of a novel furnace cover suitable for a carbonization furnace of the utility model is shown;

[0023] Figure 3 A side view of a center furnace cover of a novel furnace cover suitable for a carbonization furnace of the utility model is shown;

[0024] Figure 4 A partial enlarged view of an edge furnace cover of a novel furnace cover suitable for a carbonization furnace of the utility model is shown;

[0025] Figure 5 A reference schematic diagram of an existing furnace cover is shown.

[0026] Mark explanation: 1, center furnace cover, 2, edge furnace cover. DETAILED DESCRIPTION

[0027] It should be understood that the embodiments of the present application shown in the example embodiments are only illustrative. Although only a few embodiments are described in detail in the present application, those skilled in the art can easily appreciate that various modifications are feasible without departing from the teachings of the subject matter of the present application. Accordingly, all such modifications should be included within the scope of the present application. Other substitutions, modifications, changes and omissions can be made to the design, operating conditions and parameters of the following example embodiments without departing from the main idea of the present application.

[0028] The present application provides a novel furnace cover suitable for carbonization furnace, please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , comprising: center furnace cover 1 and edge furnace cover 2;

[0029] The center furnace cover 1 and edge furnace cover 2 are densely arranged pipe type structure, which are densely arranged by parallel seamless steel pipes;

[0030] The center furnace cover 1 and edge furnace cover 2 are mechanically connected;

[0031] The material of the center furnace cover 1 and edge furnace cover 2 is stainless steel.

[0032] The densely arranged pipe type structure increases the heat exchange area by densely arranging seamless steel pipes, thereby improving the thermal efficiency. During the working process of the furnace cover, heat can be more effectively absorbed and dissipated, ensuring the stability and uniformity of the temperature in the furnace. The seamless steel pipe has excellent heat conduction performance, which can quickly transfer heat to the cooling medium, further improving the heat dissipation performance.

[0033] Seamless steel pipes are used, and the steel pipes are closely arranged, forming a solid support structure. This structure not only improves the carrying capacity of the furnace cover, but also enhances its anti-deformation and anti-vibration capabilities. In the long-term use process, it can resist the influence of high temperature, corrosion and mechanical stress and other adverse conditions, thereby prolonging the service life of the furnace cover.

[0034] In some embodiments, please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , the center furnace cover 1 is composed of three identical furnace covers.

[0035] The three-part design makes the installation process of the furnace cover more convenient. Each part of the furnace cover can be positioned and installed independently, reducing the complexity and time cost of the overall installation. When the furnace cover needs to be maintained or replaced, the three-part design makes the disassembly process easier. A certain part of the furnace cover can be disassembled individually without affecting the normal operation of other parts, thereby improving the efficiency and convenience of maintenance.

[0036] In some embodiments, referring to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the edge hood 2 is composed of six identical hood petals.

[0037] The edge hood 2 often needs to be cleaned to remove accumulated dust, dirt or other impurities. The design of six petals makes the disassembly process easier, facilitating thorough cleaning and inspection. The six petals are tightly fitted together to form a solid overall structure. It helps to disperse the stress borne by the hood and improve the overall structural strength. The gaps between the six petals can be sealed by sealing strips or other sealing devices to ensure that the heat and gas inside the furnace do not leak to the outside environment. It helps to improve the sealing performance of the hood, reduce energy waste and environmental pollution.

[0038] In some embodiments, referring to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the seamless steel pipe is filled with cooling medium inside.

[0039] The main purpose of filling the cooling medium inside the seamless steel pipe is to exchange heat to control or regulate the temperature of the fluid inside the pipe. The cooling medium can be water, oil or other suitable fluid for specific application scenarios. Through circulating flow, the cooling medium can absorb the heat of the fluid inside the pipe and carry it away, thereby achieving the effect of cooling.

[0040] In some embodiments, referring to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the parallel seamless steel pipes are welded.

[0041] Welding can provide a strong connection to ensure the overall strength and stability of the piping system. The welded joint can form a tight seal to prevent fluid leakage and ensure the safety of the piping system. The welded connection does not require additional connectors, which can save space and make the piping layout more compact. The welded joint is relatively simple and easier to inspect and repair during maintenance.

[0042] In some embodiments, referring to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the pipe way of the seamless steel pipe is connected by flexible connection elbows.

[0043] Flexible connection bends can absorb the deformation of the pipeline caused by temperature changes, pressure fluctuations or foundation settlement, etc., so as to protect the pipeline system from damage. Flexible connection bends can smoothly guide fluid flow, reduce resistance of fluid during turning, and improve the efficiency of fluid transmission of the pipeline system. Flexible connection bends have the characteristics of easy installation and maintenance, which can reduce the construction difficulty and time cost.

[0044] In some embodiments, referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , the outer diameter of the seamless steel pipe ranges from 80 to 90 mm, and the inner diameter ranges from 50 to 60 mm.

[0045] In some embodiments, referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , the stainless steel includes 316L.

[0046] 316L stainless steel has excellent corrosion resistance, especially in chloride environments, which is better than 304 stainless steel. This makes it the preferred material for industries such as marine, chemical, food processing, etc. 316L stainless steel has high strength and toughness, and can withstand large stress and pressure. At the same time, its low temperature toughness is also good, suitable for application in low temperature environment. Because the carbon content of 316L stainless steel is low, its welding performance is excellent, and it is not easy to produce welding cracks. This makes it more stable and reliable during welding. 316L stainless steel is easy to process and form, and can be processed by stamping, bending, stretching and other processes.

[0047] In some embodiments, referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , the edge furnace cover 2 includes multiple groups of water inlet and return water inlet, and the water inlet and return water inlet are arranged adjacent to each other.

[0048] The adjacent arrangement of the water inlet and return water inlet helps to achieve rapid circulation and heat exchange of the fluid. Hot fluid enters the inside of the furnace cover through the water inlet, exchanges heat with the furnace cover, and then flows out through the return water inlet. This layout reduces the flow resistance of the fluid in the pipeline and improves the heat exchange efficiency.

[0049] The adjacent arrangement of the water inlet and return water inlet makes the structural layout of the furnace cover more compact and reasonable. This design not only saves space, but also helps to improve the overall strength and stability of the furnace cover.

[0050] The water inlet and the water return are arranged adjacently, so that it is more convenient during maintenance and management.

[0051] In some embodiments, referring to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the water amount of the center cover 1 ranges from 30 to 40 cubic meters per hour.

[0052] In the use process, the proper cover water cooling pipeline and structure form are selected and determined; the cover cooling condition parameters are determined, the maximum cooling water amount is calculated, and the branch water amount is distributed; the water passing pipe diameter is calculated and determined, the pipeline path is optimized, the flow velocity and flow amount are ensured, the material selection is analyzed, and the optimal material is determined; the structure design drawing is designed, the machining and pipeline blanking and welding are carried out, the forming is assembled, the pressure test is carried out, and the online replacement and water passing test are carried out.

[0053] The purpose of the utility model is to solve the problems of abnormal water leakage and short service life of the cover by using a new material and a new form of cover, and the solution is divided into two stages.

[0054] The first stage: the traditional cover condition is explained. Figure 1 Figure 2 Figure 3 Figure 4 Figure 1 Figure 2 Figure 3 Figure 4 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 ,

[0055] A company has a 60T carbonization furnace, and the cover is fixedly installed, and the initial design is divided into a center cover 1 and an edge cover 2, the center cover 1 adopts a stainless steel plate type water cooling structure, and three pieces are assembled together. The edge cover 2 adopts a 20g medium-low pressure boiler pipe water cooling structure type, and six pieces are assembled together. Since the production, the center cover 1 has appeared the steel plate open welding water leakage in the electrode hole area. After three months of production, the edge cover 2 has appeared the longitudinal crack of the pipe body and the welding opening in the furnace inlet area and the smoke hood area, and the cover frequently leaks water, which seriously restricts the production. Through technical analysis, the original center cover 1 adopts the plate type water cooling structure, the water channel section is rectangular, part of the cooling water path is 180° turned, the water flow resistance is large, the flow velocity is small, and the cooling effect is poor. There are many internal and external welds between the water channel partitions, when the internal partition is open welded, the inlet and return water cavities are connected, the internal circulation dead zone is formed, the local water is boiled and vaporized, the cavitation and vibration are generated, the external partition is open welded, and the water leakage frequently occurs. The original edge cover 2 adopts the water cooling coil cooling type, under normal circumstances, the densely arranged pipe type water cooling cover has the advantages of small cooling water circulation resistance, uniform cooling, good cooling effect and no internal weld. However, the cover has the superimposed welding of the densely arranged pipe and the rib plate and the elbow in the structure, the pipe body of the part of the reserved hole is insufficiently reinforced by the pipe rib, even the external reinforcing rib cannot be welded, the pipe body is subjected to the heat radiation for a long time, the pipe body is bent, and the pipe body and the welding opening are cracked, and the water leakage occurs.

[0056] From the material analysis, the original center cover 1 uses 1Cr18Ni9Ti stainless steel, and the edge cover 2 uses 20g. The purpose of using stainless steel in the center cover 1 is to resist corrosion, high strength and non-magnetic performance. 1Cr18Ni9Ti stainless steel is ordinary stainless steel (SUS321), which is austenitic type, and the use temperature requirement is less than 750℃. If it needs to be used in high temperature environment, it must be solid solution treated, and the mechanical properties will decrease. The original edge cover 2 is made of 20g, which refers to 20# steel, which is boiler plate. 20g is a high-quality carbon structural steel, which is a boiler material. The carbon content is 0.16-0.24%, the tensile strength is 410Mpa, and the yield point is 230-250Mpa (GB3087 low pressure, GB5310 high pressure). 20g also has some trace elements which are more suitable for the characteristics of boiler pressure vessels. In addition, 20g also emphasizes its physical properties, such as bending, impact and tensile properties. The heat resistance temperature requirement is less than 450℃.

[0057] In high temperature environment, ordinary low alloy steel will have high temperature oxidation reaction, and the crystal phase organization will work in high temperature and stress conditions for a long time. Due to high temperature, the diffusion ability of alloy element atoms increases, which will lead to the transfer process between solid solution and carbide phase. Those alloy elements which strengthen the solid solution, such as chromium, molybdenum and manganese, will continue to dissolve, while the alloy elements in the carbide phase will gradually increase, that is, the alloy elements transfer from solid solution to carbide, which will cause the depletion of alloy elements in solid solution, and also cause the metal to peel off, delaminate, and have defects such as pitting and pits on the surface.

[0058] At present, the center temperature of carbonization furnace smelting is as high as 1800℃ or above, and the flue gas temperature of cover area also reaches about 100℃. In high temperature environment, 1Cr18Ni9Ti stainless steel and 20g material will produce plastic deformation and creep with the increase of time even if the stress is less than the yield strength. At the same time, the flue gas in the furnace and the rising molten slag liquid directly contact the heat exchange coil, which causes the parent material of the coil to be roasted for a long time under high temperature. The tensile strength and yield point of the material will change under high temperature environment, which will reduce the allowable stress, cause the strength to decrease, produce thermal plastic deformation, and also produce creep and instantaneous strain. When the creep reaches the limit and the endurance strength decreases significantly, it will accelerate the creep speed of high temperature pressure parts in the use process, reduce the working life, cause the accelerated destruction of steel under high temperature and stress, and cause the parent material to break.

[0059] Second stage: selection and production of new type cover.

[0060] Improved optimized furnace cover. First, from the structure of the furnace cover, the selection of water cooling pipe structure, the original structure type of the center furnace cover 1 is plate type water cooling structure, and the water cooling dense pipe type has the advantages of small cooling circulation resistance, uniform cooling, no internal weld and other advantages. Transforming the original center furnace cover 1 into a dense pipe structure is an effective way to solve the problem. Secondly, from the selection of material. The original center furnace cover 1 uses 1Cr18Ni9Ti stainless steel, and the edge furnace cover 2 uses 20g. From the current carbonization furnace smelting environment and temperature, the existing material cannot meet the actual working condition requirements, which has a great influence on the subsequent continuous and stable use. Through the query of the commonly used materials in the industry at present, and considering the manufacturing and maintenance cost, finally two kinds of materials are selected for optimization and improvement, which are 316L and 310S.

[0061] 310S (old brand 0Cr25Ni20 / new brand 06Cr25Ni20) stainless steel is an austenitic chromium-nickel stainless steel, which has good oxidation resistance, corrosion resistance, and better creep strength due to high percentage of chromium and nickel, which can work continuously at high temperature. Its melting point is 1470℃, and the stainless steel has good high temperature resistance. When the temperature exceeds 800, it begins to soften, and the allowable stress begins to decrease continuously, and the maximum use temperature is 1200℃. Due to high nickel (Ni) and chromium (Cr) content, it has good oxidation resistance, corrosion resistance, acid and alkali resistance, and high temperature resistance. High temperature resistant steel pipe is specially used for manufacturing electric heating furnace pipe and other occasions. The chemical composition of austenitic stainless steel is based on chromium and nickel, with the addition of molybdenum, tungsten, niobium and titanium elements. Due to its face-centered cubic structure, it has high strength and creep strength at high temperature. Tensile strength (бb) (Mpa): ≥515 Yield strength (σs) (Mpa): ≥205 Elongation (δ) %: ≥35 Area reduction (ψ) %: ≥50. Recommended heat treatment system: 1030℃-180℃, quenching; Mechanical properties include (1.) Tensile strength: not less than 520; (2.) Specified non-proportional elongation strength: not less than 205; (3.) Elongation after fracture: not less than 35.

[0062] 316L is a stainless steel material grade. AISI 316L is the corresponding American standard, and SUS 316L is the corresponding Japanese standard. my country's unified numerical code is S31603, and the standard grade is 02Cr17Ni12Mo2 (new standard), while the old grade was 00Cr17Ni14Mo2. This indicates that it mainly contains Cr, Ni, and Mo, with the numbers representing the approximate percentages. The national standard is GB / T20878-2007 (current version). Material grade: 02Cr17Ni12Mo2. Due to the addition of Mo (2-3%), it has excellent corrosion resistance (especially pitting corrosion resistance), high temperature resistance, and creep resistance. Melting point: 1371~1398℃, tensile strength σb (MPa): ≥480, yield strength σ0.2 (MPa): ≥177, elongation δ5 (%): ≥40, reduction of area ψ (%): ≥60. Hardness: ≤187HB; ≤90HRB; ≤200HV. Solution treatment at 1010-150℃ followed by rapid cooling.

[0063] The main difference in chemical composition between 316 and 304 stainless steel is that 316 contains molybdenum (Mo). It is generally accepted that 316 has better corrosion resistance, especially at high temperatures. Therefore, 316 is typically chosen for components used in high-temperature environments. Its corrosion resistance is superior to 304 stainless steel, exhibiting excellent corrosion resistance in pulp and paper production processes. Furthermore, 316 stainless steel is resistant to marine and corrosive industrial atmospheres. Heat resistance: 316 stainless steel exhibits good oxidation resistance in intermittent use below 1600°C and continuous use below 1700°C. Continuous use of 316 stainless steel is best avoided within the 800-1575°C range, but it exhibits good heat resistance when used continuously outside this temperature range. 316L stainless steel has better resistance to carbide precipitation than 316 stainless steel and can be used within the aforementioned temperature range. Welded sections of 316 stainless steel require post-weld annealing. Post-weld annealing is not required for 316L stainless steel.

[0064] Currently, the reducing agent used in carbonization furnaces is coke oven dry quenching dust. When the coke in the furnace is not completely burned, the flue gas contains the following components: CO2, SO2, N2, O2, water vapor, CO, H2, CH4, and a small amount of HCl. The small amount of HCl in the flue gas mainly enters the flue gas in the form of HCl, which mainly originates from the raw materials entering the furnace, namely coke oven dust. Given the corrosion of the furnace cover and flue system by HCl, the corrosion mechanism of chloride ions on ordinary carbon steel is the destruction of the protective film on the metal surface, forming a corrosion layer, causing delamination and peeling of the pipe wall, and ultimately reducing the yield strength and tensile strength of the metal. At the same time, ordinary austenitic stainless steel is more susceptible to chloride ion corrosion, which can cause a combination of pitting corrosion and stress corrosion. These corrosion layers are easy to peel off, forming corrosion pits in local areas of the pipe wall. The pipe wall is thin in the pit area and the corrosion extends radially, eventually leading to pipe wall perforation. By comparison, 316L with added Mo (2-3%) has excellent corrosion resistance, and its resistance to chloride ions is far better than that of 310S and 304 austenitic stainless steel.

[0065] Based on the physicochemical properties of the three commonly used materials, a comparison is shown in Table 1:

[0066] Table 1. Physicochemical properties of the three materials

[0067]

[0068] Based on performance comparison, 316L material is best suited to the current carbonization furnace smelting conditions, so this material was selected for optimization and improvement of the furnace cover material.

[0069] The production of new-type furnace covers requires the selection of appropriate pipe and structural forms, determination of cooling condition parameters, mainly water volume, water pipe diameter, pipe routing, etc., and finally determination of materials, which are then completed by a professional manufacturer.

[0070] The above embodiments are possible examples of implementations of this utility model, and are provided only to enable those skilled in the art to clearly understand the principles of this utility model. Those skilled in the art should understand that the above discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this utility model (including the claims) is limited to these examples. Under the overall concept of this utility model, the technical features of the above embodiments or different embodiments can also be combined with each other, resulting in many other variations of different aspects of the embodiments of this utility model as described above. For the sake of brevity, these variations are not provided in the specific embodiments. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this utility model should be included within the protection scope claimed by this utility model.

Claims

1. A novel furnace cover suitable for carbonization furnaces, characterized in that, include: The central furnace cover (1) and the edge furnace cover (2); The central furnace cover (1) and the edge furnace cover (2) are densely arranged tube structures, consisting of parallel seamless steel pipes arranged densely. The central furnace cover (1) and the edge furnace cover (2) are mechanically connected; The central furnace cover (1) and the edge furnace cover (2) are made of stainless steel.

2. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The central furnace cover (1) consists of three identical furnace cover segments.

3. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The edge furnace cover (2) consists of six identical furnace covers.

4. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The seamless steel pipe is filled with a cooling medium.

5. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The parallel seamless steel pipes are welded together.

6. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The seamless steel pipe uses flexible connection elbows for its pipeline route.

7. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The outer diameter of the seamless steel pipe ranges from 80 to 90 mm, and the inner diameter ranges from 50 to 60 mm.

8. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The stainless steel includes 316L.

9. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The edge furnace cover (2) includes multiple sets of water inlets and water outlets, which are arranged adjacent to each other.

10. The novel furnace cover for a carbonization furnace according to claim 1, characterized in that, The water volume of the central furnace cover (1) is in the range of 30-40 cubic meters per hour.

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