Graphitization blast furnace architecture system

Abstract

The invention belongs to the technical field of blast furnace ironmaking, and particularly relates to a graphitization blast furnace framework system which comprises a furnace base, a hearth and a furnace body, the hearth is arranged above the furnace base, the hearth and the furnace body are integrally formed, a furnace shell is arranged on the periphery of the hearth and the furnace body, and the periphery of the furnace base and the furnace shell are welded into a whole. The upper portion of the furnace base is directly connected with a graphite wall at the bottom in the hearth through a carbon ramming layer, the furnace body comprises a heat insulation layer and cooling plates, the heat insulation layer is poured on the inner side of the furnace shell, the multiple cooling plates penetrate through the furnace shell and the heat insulation layer to be installed in an inserted mode from top to bottom, graphite bricks are poured between the cooling plates, and gaps between the cooling plates and the graphite bricks are smaller than 0.3 mm. The gaps between the cooling plates and the graphite bricks are not smaller than 0.3 mm, the copper sheets are inserted into the gaps, the cooling plates form a matrix type water cooling structure, and the furnace base, the hearth and the furnace body are all connected with an intelligent monitoring system. According to the framework system, the furnace foundation, the hearth and the furnace body are combined with an intelligent control and monitoring system, so that the regional temperature, stress, water quantity and furnace bottom erosion can be monitored.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and in particular relates to a graphitized blast furnace framework system. Background Art

[0002] With the rapid development of the metallurgical industry, the trend of large-scale, energy-saving and long-life blast furnaces has been promoted. High-efficiency, high-pressure and high-temperature working conditions have become the prerequisites for the advancement of ironmaking technology. The working characteristics of blast furnaces lead to temperature-pressure cyclic changes in the furnace shell. The additional stress caused by temperature cyclic changes is called thermal stress. The greater the temperature cycle change, that is, the greater the temperature difference between the upper and lower limits, the greater the thermal stress; thermal strain is the strain caused by temperature change, and the thermal conductivity of the material affects the thermal strain; the fatigue phenomenon caused by the thermal stress and thermal strain of the blast furnace under working conditions is the thermal fatigue of the blast furnace shell. The interior of the blast furnace is filled with oxygen, coal gas, carbon dioxide, hydrogen, water vapor, nitrogen and alkali metal gaseous high-temperature medium atmosphere, and the fracture and fatigue under the action of the medium environment are the result of the interaction of three factors: stress, metal material and medium. Impact stress, thermal fatigue and corrosion fatigue damage after the damage of the furnace lining driven by molten iron erosion are common problems of blast furnaces. After the temperature of the furnace shell increases due to problems such as the shedding of refractory materials in the middle and late stages of production, thermal fatigue and high-temperature creep are important causes of furnace shell damage. According to the empirical analysis of historical data, the inner surface of the blast furnace shell is subjected to alternating tensile stress and corrosion. Therefore, it can be judged that the main causes of blast furnace shell damage should be impact stress, corrosion fatigue, melting loss, etc.

[0003] Public data shows that in recent years, about 70% of large blast furnaces in China have been in service for 8-10 years, and blast furnace failures occur frequently. The abnormal failure phenomena mainly manifest as deformation of the furnace bottom, high temperature of the side walls of the furnace cylinder, red-hot cracking of the blast furnace body, cooling system exceeding its limit, cracking of the furnace shell and overflow of gas or molten iron, etc. Summary of the invention

[0004] The object of the present invention is to provide a graphitization blast furnace architecture system to solve the problems of short service life and frequent blast furnace abnormalities in existing blast furnaces.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: A graphitized blast furnace architecture system comprises a furnace base, a furnace cylinder and a furnace body, wherein the furnace base is provided with a furnace cylinder above, the furnace cylinder and the furnace body are formed in one piece, a furnace shell is arranged around the furnace cylinder and the furnace body, the periphery of the furnace base and the furnace shell are welded and connected as one, the furnace cylinder comprises a graphite wall, the furnace base is directly connected to the graphite wall at the bottom of the furnace cylinder through a carbon ramming layer above the furnace base, the furnace body comprises a heat insulation layer and a cooling plate, the heat insulation layer is cast on the inner side of the furnace shell, a plurality of the cooling plates are inserted from top to bottom through the furnace shell and the heat insulation layer, graphite bricks are cast between the cooling plates, the gap between the cooling plates and the graphite bricks is less than 0.3 mm, the cooling plates constitute a matrix water cooling structure, and the furnace base, the furnace cylinder and the furnace body are all connected to an intelligent monitoring system.

[0006] Preferably, the furnace base includes a plastic carbon layer, a water cooling system, high-strength heat-resistant concrete, a reinforcement plate and a load-bearing structure, a water cooling system is installed in the middle of the load-bearing structure, high-strength heat-resistant concrete is poured at the bottom of the load-bearing structure, a reinforcement plate is added below the load-bearing structure, a plastic carbon layer is arranged above the load-bearing structure, the heat at the bottom of the furnace cylinder is transferred to the furnace base water cooling system to establish a stable furnace bottom heat transfer path, the plastic carbon layer is above the furnace bottom substrate, the furnace bottom substrate is provided with sieve welding holes, and the furnace bottom substrate is provided with grouting pipes and overflow pipes. The furnace base is an important part of the blast furnace architecture system, and is combined with an intelligent monitoring system to form a situation awareness system with high rigidity, micro-stress, strong sealing, and adjustable cooling capacity, so that regional temperature, stress, water volume, and furnace bottom erosion can be monitored. The furnace base is upgraded from the original single heat transfer structure to a multi-layer micro-stress strong cooling furnace base equipment system to realize regional parameter perception processing.

[0007] Preferably, the furnace hearth also includes carbon bricks and a ceramic layer, a cooling wall is cast on the inner side of the furnace shell around the furnace hearth, a cooling pipe is arranged inside the cooling wall, a graphite wall is cast on the inner side of the cooling wall around the furnace hearth and on the bottom of the furnace hearth, a carbon ramming mass is laid on the inner side of the graphite wall, carbon bricks are cast on the inner side of the carbon ramming mass, a corundum insulation layer is laid on the inner side of the carbon bricks, and an anti-corrosion and alkali-proof structural ceramic layer is arranged on the inner side of the corundum insulation layer.

[0008] Preferably, the water cooling system comprises water cooling pipes, a plurality of the water cooling pipes penetrate between the load-bearing structure and the plastic carbon layer, both ends of the water cooling pipes extend outward and are sheathed with a protective structure.

[0009] Preferably, the gap between the graphite bricks of the graphite wall is less than 0.5 mm.

[0010] Preferably, the gap between the cooling plate and the graphite brick is not less than 0.3 mm of the inserted copper sheet.

[0011] Preferably, the copper skin has a thickness of 0.2 mm.

[0012] Working principle: The furnace base is composed of a load-bearing structure combined with a strengthening plate to form a multi-layer truss load-bearing structure system. The furnace cylinder is formed with a double-layer buffer expansion joint through carbon ramming material and corundum insulation layer. The furnace body adopts a matrix cooling method with multiple cooling plates. Combined with the intelligent control and monitoring system, the regional temperature, stress, water volume, and furnace bottom erosion can be monitored. The intelligent control and monitoring system is characterized by a dense matrix coaxial and different diameter thermocouple data acquisition mode in the core area of ​​the iron mouth, combined with the induction and integration of system parameters such as water volume, temperature difference, pressure, stress, temperature, and raw material comprehensive real-time indicators of relevant parts of the blast furnace, combined with the expert system database, using a two-dimensional steady-state heat transfer numerical algorithm and computer software The technology of parts provides a furnace erosion model and visualization model for monitoring the health of the furnace at multiple levels and angles. It can continuously and accurately grasp the position of the 1450℃ molten iron line inside the furnace bottom, the position of the 1150℃ solidification line, the position of the furnace bottom wall after erosion, the isotherms of the furnace bottom wall, the temperature field, the solidification layer and the thickness of the slag skin and other real-time data. It is also deduced based on the numerical simulation of the erosion of the furnace bottom wall, and the shape of the dead material column in the furnace, the porosity of the dead material column, etc. are estimated. According to public information, the accelerated erosion of the core area of ​​the blast furnace iron mouth is due to the increase in the diameter of the dead material column, which reduces the distance from the iron mouth and intensifies the violent scouring of the molten iron circulation and eddy current along the side wall of the furnace. The porosity of the dead material column affects the circulation speed of the molten iron in the coke-free area by affecting the flow behavior of the molten iron inside the dead material column. The intelligent control and monitoring system of the blast furnace furnace reminds the blast furnace expert system to optimize the production raw material control from the outside, adjust the relevant working condition process parameters; and improve the local cooling intensity of the furnace from the inside, etc., to ensure the timely stabilization of the furnace.

[0013] Based on cross-border thinking and first principles and improving the heat transfer efficiency of the furnace, the cross-border integration of the cooling system and the blast furnace lining system is achieved. The cross-border thinking of the cooling system is the abandonment of the Fourier heat transfer formula and the application of the cross-border Fourier heat transfer formula. Q=-KAdt / dx, where k is the heat transfer coefficient. When the heat transfer coefficient of the traditional cooling system is less than the heat transfer coefficient of the new quality furnace lining, the graphite system becomes the actual enlarged cooling system to expand into the furnace. The furnace cooling wall system can be regarded as the cooling medium water transferring heat energy through a thickened channel. Through the 4-fold increase in the heat transfer coefficient, the integration of the cooling system and the furnace lining system is formed, realizing the expansion of the blast furnace deep cooling process.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) The furnace base is composed of a load-bearing structure combined with a reinforcement plate to form a multi-layer truss load-bearing structure system, which greatly increases the rigidity, improves the ability to resist bending moments under blast furnace working conditions, and eliminates the probability of irregular deformation of the blast furnace bottom; the furnace base structure system is subjected to a series of processes such as stress relief treatment and vacuum method test of the air tightness of the furnace base weld to achieve overall micro-stressing and ensure the long-term stability of the blast furnace bottom; a regional adjustment water cooling system is used to establish a thermal balance path for the furnace bottom with the furnace cylinder system to maintain the atmosphere; (2) A double-layer buffer expansion joint is formed in the furnace by carbon ramming material and corundum insulation layer, which eliminates the thermal strain and expansion of the furnace under working conditions and reduces the stress in the furnace structure system; combined with the intelligent control and monitoring system, data analysis is realized, and the heat transfer capacity and furnace cooling capacity of the blast furnace production process are controlled in real time, which effectively maintains the cold surface temperature of the ceramic layer lining at a low level for a long time, reduces the mechanical erosion damage of the side wall ceramic layer by the molten iron circulation, reduces the degree of melting of carbon bricks by incompletely saturated carbon molten iron, reduces the probability of alkali metal corrosion of the furnace, and greatly reduces the probability of local high temperature abnormalities of the furnace carbon bricks; adopts the blast furnace deep cooling process to expand and improve the cooling efficiency; the extremely high thermal resistance of the furnace insulation structure layer reduces the heat loss in the furnace molten iron storage and collection area; the secondary heat equalization capacity of the graphite wall realizes the temperature uniformity of the furnace side wall and prolongs the service life of the furnace; (3) The furnace body adopts a matrix cooling method composed of multiple cooling plates. The cooling plates belong to the horizontal point deep cooling method and have an extremely long service life. The effective cooling area of ​​the cooling plates inside the blast furnace is equivalent to the area of ​​the furnace shell in the area twice. From the analysis of the safety protection system, the matrix cooling plates embedded in the graphite furnace body structure have excellent resistance to impacts inside the furnace. In the event of a single cooling plate failure, the impact force generated inside the furnace to damage the furnace shell is proportional to the cross-sectional area of ​​the cooling plate. According to the failure probability calculation method of the blast furnace structure system, it is inferred that under normal operating conditions, the thermal stress impact comparison value of the flat cooling plate and the cooling wall cooling method in the high-temperature melting zone of the blast furnace when encountering extreme fault damage is 1:40, and the fault impact damage faced is more than 40 times different, that is, the area of ​​the damaged cooling plate determines the size of the fault. Therefore, the intensive plate cooling combined with the graphitized blast furnace structure improves the overall safety integrity level of the blast furnace body. (4) Improve the cooling performance of the blast furnace through the water cooling system and cooling plates, maintain the reasonable thickness of the blast furnace lining for a long time, and avoid electrochemical corrosion; improve the overall strength of the furnace shell and reduce the retention of corrosive media; timely maintain the furnace shell when the temperature rises to reduce the adverse effects of thermal fatigue; use insulation layer protection to reduce the corrosion of the furnace shell by the gaseous high-temperature medium atmosphere; maintain the low-temperature atmosphere of the blast furnace structure system, reduce the expansion, stress and deformation of the structure system caused by large temperature changes; reduce or eliminate residual stress in the weld to reduce the possibility of fatigue damage; (5) The configuration of data collection points in the blast furnace's intelligent control and monitoring system is based on the needs of the middle and late stages of the blast furnace's service life. Combined with the cooperation of the graphite wall, it has the ability to fully realize the accurate analysis of the degree of continuous erosion of abnormally high-temperature parts of the furnace hearth; it fully covers the blast furnace hearth area and realizes control and monitoring without blind spots. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a cross-sectional view of the side wall structure of the furnace body in the present invention; Figure 3 It is a structural cross-sectional view of the furnace base in the present invention; Figure 4 It is a cross-sectional view of the side wall structure of the furnace in the present invention; Figure 5 It is a structural schematic diagram of the water cooling system of the furnace base in the present invention; Figure 6 It is a schematic diagram of the structure of the water cooling pipe in the water cooling system of the furnace base in the present invention.

[0016] Explanation of the accompanying drawings: 1. furnace base; 10. sieve welding hole; 11. plastic carbon layer; 12. water cooling system; 13. high-strength heat-resistant concrete; 14. reinforcement plate; 15. load-bearing structure; 16. furnace bottom base plate; 17. grouting pipe; 18. overflow pipe; 19. water cooling pipe; 2. furnace cylinder; 21. graphite wall; 22. carbon brick; 23. ceramic layer; 24. cooling wall; 25. cooling pipe; 26. carbon ramming material; 27. corundum insulation layer; 3. furnace body; 31. insulation layer; 32. cooling plate; 33. graphite brick; 34. copper skin; 4. furnace shell; 5. carbon ramming material layer. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings and embodiments.

[0018] like Figure 1-4 As shown, a graphitization blast furnace architecture system includes a furnace base 1, a furnace cylinder 2 and a furnace body 3. The furnace cylinder 2 is above the furnace base 1. The furnace cylinder 2 and the furnace body 3 are formed in one piece. A furnace shell 4 is arranged outside the furnace cylinder 2 and the furnace body 3. The furnace base 1 is welded to the furnace shell 4 as a whole. The furnace cylinder 2 includes a graphite wall 21. The top of the furnace base 1 is directly connected to the graphite wall 21 at the bottom of the furnace cylinder 2 through a carbon ramming layer 5. The furnace body 3 includes a heat insulation layer 31. The heat insulation layer 31 and a cooling plate 32 are cast inside the furnace shell 4. The heat insulation layer 31 is used for protection to reduce the corrosion of the furnace shell by the gaseous high-temperature medium atmosphere. A plurality of cooling plates 32 pass through the furnace shell 4 and the heat insulation layer 31. Layer 31 is inserted from top to bottom, graphite bricks 33 are cast between cooling plates 32, the gap between cooling plates 32 and graphite bricks 33 is less than 0.3mm, the gap between cooling plates 32 and graphite bricks 33 is not less than 0.3mm, copper sheet 34 is inserted to adjust the gap width, the thickness of copper sheet 34 is 0.2mm, cooling plates 33 form a matrix water cooling structure, the effective cooling area of ​​cooling plates inside the blast furnace is equivalent to the area of ​​furnace shell in the area twice, and the matrix cooling plates are embedded in the graphite furnace body structure, which has excellent ability to resist impact inside the furnace; furnace base 1, furnace cylinder 2 and furnace body 3 are all connected to the intelligent monitoring system.

[0019] A further embodiment of the present invention is as follows Figure 3 , 56, the furnace base 1 includes a plastic carbon layer 11, a water cooling system 12, a high-strength heat-resistant concrete 13, a reinforcement plate 14 and a load-bearing structure 15. The water cooling system 12 is installed in the middle of the load-bearing structure 15, and the high-strength heat-resistant concrete 13 is poured at the bottom of the load-bearing structure 15. A 40-60 mm thick reinforcement plate 14 is added below the load-bearing structure 15, so that the furnace base 1 is upgraded from a single-layer beam-slab load-bearing structure system to a multi-layer truss load-bearing structure system; a plastic carbon layer 11 is arranged above the load-bearing structure 15 to transfer the heat at the bottom of the furnace cylinder 2 to the water cooling system of the furnace base 1 to establish a stable furnace bottom heat transfer path, and the ... The furnace bottom base plate 16 is located above the carbon layer 11. The furnace bottom base plate 16 is provided with a grouting pipe 17 and an overflow pipe 18. The furnace bottom base plate 16 is provided with a sieve welding hole 10, which is used for grouting and overflow inspection of the blast furnace base, eliminating the air in the carbon layer, improving the thermal conductivity, and detecting the welding quality of the furnace bottom base plate and the load-bearing structure; it is removed after the inspection, and the grouting pipe 17 and overflow pipe 18 are not needed in the production process. The water cooling system 12 includes a water cooling pipe 19, and multiple water cooling pipes 19 run through the load-bearing structure 15 and the plastic carbon layer 11. The two ends of the water cooling pipe 19 extend outward and are surrounded by a protective structure. The furnace base is combined with an intelligent monitoring system to form a situation awareness system with high rigidity, micro-stress, strong sealing, and adjustable cooling capacity, so that regional temperature, stress, water volume, and furnace bottom erosion can be monitored. The furnace base is upgraded from the original single heat transfer structure to a multi-layer micro-stress strong cooling furnace base equipment system to realize regional parameter perception and processing.

[0020] A further embodiment of the present invention is as follows Figure 4 As shown, the furnace 2 also includes carbon bricks 22 and a ceramic layer 23. A cooling wall 24 is cast inside the furnace shell 4 around the furnace 2. A cooling pipe 25 is arranged inside the cooling wall 24. A graphite wall 21 is cast inside the cooling wall 24 around the furnace 2 and at the bottom of the furnace 2. A carbon ramming material 26 is laid inside the graphite wall 21. A carbon brick 22 is cast inside the carbon ramming material 26. A corundum insulation layer 27 is laid inside the carbon brick 22. An anti-corrosion and anti-alkali structural ceramic layer 23 is arranged inside the corundum insulation layer 27. The gap between the graphite bricks of the graphite wall 21 is less than 0.5 mm. The cooling wall in the furnace and the graphite with high heat transfer rate are The new process of direct contact with the wall to achieve cross-border integration of the cooling system and the furnace lining system is characterized by comprehensively reducing the working temperature of the hot surface of the cooling wall, effectively reducing the influence of the heat transfer blind area between the cooling walls, and improving the heat transfer efficiency of the low-temperature zone of the blast furnace cooling; the ceramic layer and the insulation layer on the inside of the furnace body jointly form the primary insulation structure system of the blast furnace, and the low thermal conductivity slag skin protective layer formed on the hot surface of the high-temperature melting area for a long time is the secondary insulation layer, which comprehensively reduces the loss of external heat energy of the blast furnace body under working conditions while also enhancing the performance of resisting furnace erosion, reducing carbon consumption and achieving energy saving.

[0021] After the new blast furnace architecture system process upgrade, the median temperature of the furnace is 214 degrees and the maximum temperature is 260 degrees; this is equivalent to a reduction of about 23% in the heat energy loss of the furnace after the new upgrade.

[0022] The results were inferred from the actual erosion data when the blast furnace was in operation for 46 months, combined with the analysis of ceramic material performance indicators. The ceramic layer of the hearth was eroded by about 150 mm, and the annual hearth erosion thickness was 39.47 mm, which was much less than the hearth erosion of the previous generation of furnaces. Combined with the display and judgment of the area by the temperature measurement system, the hearth isotherms during actual production operation were consistent with the planning model. The heat flux of the hearth lining structure was reduced by 67% compared with the carbon hearth lining, saving a total of 18,346 tons of standard coal annually, with good low-carbon energy-saving effects. The temperature of the blast furnace shell was below 50 degrees on average, and the vertical expansion measurement value of the blast furnace was 16 mm. The relevant data were significantly lower than the parameter values ​​of the traditional blast furnace framework system during the same period, proving that the graphitized blast furnace framework system was in a low stress range during operation.

Claims

1. A graphitization blast furnace architecture system, comprising a furnace base, a furnace cylinder and a furnace body, characterized in that: A furnace cylinder is located above the furnace base, and the furnace cylinder and furnace body are integrally formed. A furnace shell is arranged around the furnace cylinder and the furnace body, and the furnace base and the furnace shell are welded together as a whole. The furnace cylinder includes a graphite wall, and the top of the furnace base is directly connected to the graphite wall at the bottom of the furnace cylinder through a carbon ramming layer. The furnace body includes an insulation layer and a cooling plate. The insulation layer is cast on the inside of the furnace shell, and a plurality of cooling plates are inserted from top to bottom through the furnace shell and the insulation layer. Graphite bricks are cast between the cooling plates, and the gap between the cooling plates and the graphite bricks is less than 0.3 mm. The cooling plates constitute a matrix water-cooling structure, and the furnace base, furnace cylinder and furnace body are all connected to an intelligent monitoring system.

2. A graphitization blast furnace framework system according to claim 1, characterized in that: The furnace base includes a plastic carbon layer, a water cooling system, high-strength heat-resistant concrete, a reinforcement plate and a load-bearing structure. The water cooling system is installed in the middle of the load-bearing structure, high-strength heat-resistant concrete is poured at the bottom of the load-bearing structure, a reinforcement plate is added below the load-bearing structure, and a plastic carbon layer is arranged above the load-bearing structure to transfer the heat at the bottom of the furnace cylinder to the furnace base water cooling system to establish a stable furnace bottom heat transfer path. Above the plastic carbon layer is a furnace bottom base plate, screen welding holes are arranged on the furnace bottom base plate, and grouting pipes and overflow pipes are installed on the furnace bottom base plate.

3. A graphitization blast furnace framework system according to any one of claims 1 or 2, characterized in that: The furnace hearth also includes carbon bricks and ceramic layers. A cooling wall is cast on the inner side of the furnace shell around the furnace hearth. A cooling pipe is arranged inside the cooling wall. A graphite wall is cast on the inner side of the cooling wall around the furnace hearth and on the bottom of the furnace hearth. Carbon ramming material is laid on the inner side of the graphite wall. Carbon bricks are cast on the inner side of the carbon ramming material. A corundum insulation layer is laid on the inner side of the carbon bricks. An anti-corrosion and anti-alkali structural ceramic layer is arranged on the inner side of the corundum insulation layer.

4. A graphitization blast furnace framework system according to claim 2, characterized in that: The water cooling system comprises water cooling pipes, a plurality of which penetrate between the load-bearing structure and the plastic carbon layer, and both ends of the water cooling pipes extend outwards and are sheathed with a protective structure.

5. The graphitization blast furnace framework system according to claim 3, characterized in that: The gap between the graphite bricks of the graphite wall is less than 0.5 mm.

6. The graphitization blast furnace framework system according to claim 1, characterized in that: When the gap between the cooling plate and the graphite brick is not less than 0.3mm, insert the copper sheet.

7. A graphitization blast furnace framework system according to claim 6, characterized in that: The copper sheet has a thickness of 0.2 mm.

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