RH online automatic intermittent energy-saving baking control method

Abstract

The invention provides an RH on-line automatic intermittent energy-saving baking control method. The method comprises the steps that firstly, an MFB multifunctional oxygen lance is connected with an automatic control system; secondly, after smelting of the RH vacuum furnace is finished, an MFB multifunctional oxygen lance is adopted for baking in the furnace shutdown standby state; 3, when the temperature in the furnace reaches 900 DEG C, the MFB multifunctional oxygen lance is automatically lifted up; fourthly, after the MFB multifunctional oxygen lance is lifted for 30 min to 60 min, when the temperature in the furnace is reduced to 700 DEG C to 800 DEG C, the lance is automatically lowered, ignition is conducted, and baking is conducted for 30 min to 60 min; and fifthly, the furnace operates at the temperature of 700-900 DEG C. The consumption of energy gas and oxygen for online baking is reduced by 50%, normal production is not affected, and the service life of refractory materials of RH refining furnace equipment is greatly prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of RH vacuum furnace steelmaking, and in particular to an RH online automatic intermittent energy-saving baking control method. Background Art

[0002] RH refining furnaces are widely used in converter steelmaking plants and have always occupied a vital role. However, most steel mills operate their RH refining furnaces at suboptimal capacity. When the furnaces are kept warm online while in standby mode, this wastes energy and causes excessive erosion of the RH furnace lining, shortening the service life of the vacuum tank. This negatively impacts the production of various steel grades, equipment, and safety.

[0003] In summary, the existing technology has the following problems: in RH vacuum furnace steelmaking production, there are energy waste and safety hazards. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of how to save energy and ensure safe production in RH vacuum furnace steelmaking production.

[0005] To this end, an embodiment of the present invention provides a RH online automatic intermittent energy-saving baking control method, the method comprising:

[0006] Step 1: Connect the MFB multifunctional oxygen gun to the automatic control system;

[0007] Step 2: After the RH vacuum furnace smelting is completed, the MFB multifunctional oxygen lance flame is used for heat preservation in the standby state;

[0008] Step 3: After the smelting is completed, in standby mode, when the temperature inside the RH vacuum furnace is raised to 900°, the MFB multi-function oxygen lance is automatically raised, the energy medium is turned off and the flame is extinguished;

[0009] Step 4: After lifting the MFB multifunctional oxygen gun for 30 to 60 minutes, when the temperature in the furnace drops to 700° to 800°, the gun is automatically lowered and ignited for baking for 30 to 60 minutes;

[0010] Step 5: Keep the furnace temperature between 700 and 900°C.

[0011] Specifically, the energy media used by the MFB multifunctional oxygen gun are coal gas and oxygen.

[0012] Specifically, step four includes: after the MFB multifunctional oxygen gun is lifted for 60 minutes, when the temperature in the furnace drops to 700°C, the gun is automatically lowered and ignited for baking for 60 minutes.

[0013] Specifically, step four also includes: after the MFB multifunctional oxygen gun is lifted for 30 minutes, when the temperature in the furnace drops to 800°, the gun is automatically lowered and ignited for baking for 30 minutes.

[0014] Specifically, when the temperature in the furnace drops to 700°C, the gun is automatically lowered and ignited for 60 minutes, and the gas flow rate of the MFB multi-function oxygen gun is set to 250Nm 3 / h, the oxygen flow rate is set to 180Nm 3 / h.

[0015] Specifically, when the temperature in the furnace drops to 800°C, the automatic lowering gun is ignited and baked for 30 minutes, and the gas flow rate of the MFB multi-function oxygen gun is set to 220Nm 3 / h, the oxygen flow rate is set to 300Nm 3 / h.

[0016] Specifically, after the RH vacuum furnace is finished smelting, the MFB multifunctional oxygen lance flame is used for heat preservation in the standby state;

[0017] After smelting is completed, the furnace temperature is raised to 900°C in standby mode, the MFB multifunctional oxygen lance is automatically raised, the energy medium is turned off and the flame is extinguished;

[0018] The MFB multifunctional oxygen gun is automatically controlled. When the MFB multifunctional oxygen gun is lifted, the time is automatically counted. One hour after the gun is lifted, the temperature in the furnace naturally drops to 700°. The gun is automatically lowered and ignited for baking for one hour. The gas flow is set to 220Nm 3 / h, oxygen flow rate is set to 300Nm 3 / h, continue to raise the temperature in the furnace to 900 degrees Celsius;

[0019] The MFB multifunctional oxygen lance is automatically raised and lowered for baking, with a cycle interval of 60 minutes, so that the temperature in the furnace operates at 700-900 degrees Celsius.

[0020] Specifically, after the RH vacuum furnace is finished smelting, the MFB multifunctional oxygen lance flame is used for heat preservation in the standby state;

[0021] After smelting is completed, the furnace temperature is raised to 900°C in standby mode, the MFB multifunctional oxygen lance is automatically raised, the energy medium is turned off and the flame is extinguished;

[0022] For those who need automatic control of MFB multifunctional oxygen gun, the time will be automatically set after the MFB multifunctional oxygen gun is lifted. After 30 minutes of lifting the gun, the gun will be automatically lowered and ignited for 30 minutes. The gas flow rate is set to 220Nm 3 / h, the oxygen flow rate is set to 300Nm 3 / h, continue to raise the temperature in the furnace to 900 degrees Celsius;

[0023] The MFB multifunctional oxygen gun is automatically raised and lowered for baking, with a cycle interval of 30 minutes, so that the temperature in the furnace operates at 800-900 degrees Celsius.

[0024] The beneficial effect is as follows: after RH refining is completed by adopting the technical solution of the present invention, the RH top gun enters the automatic intermittent baking mode in a long-term standby state, and the energy gas and oxygen consumption of online baking is reduced by 50% without affecting normal production, and the service life of the refractory materials of the RH refining furnace equipment is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a RH online automatic intermittent energy-saving baking control method provided by an embodiment of the present invention;

[0026] Figure 2 This is a graph of the average residual thickness of the RH vacuum furnace insert tube provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] In the embodiment of the present invention, Figure 1 , provides a RH online automatic intermittent energy-saving baking control method, the method comprising:

[0029] Step 1: Connect the MFB (Multi-Function Burner) multifunctional oxygen gun to the automatic control system; an energy medium is provided in the MFB multifunctional oxygen gun, and the energy medium is coal gas and oxygen.

[0030] Step 2: After the RH vacuum furnace smelting is completed, use the MFB multi-function oxygen lance to bake in the furnace standby state;

[0031] Step 3: When the temperature in the furnace reaches 900°, the MFB multi-function oxygen gun is automatically raised;

[0032] Step 4: After the MFB multifunctional oxygen lance is lifted for 30 to 60 minutes, when the temperature in the furnace (RH refining furnace) drops to 700° to 800°, the lance is automatically lowered and ignited for baking for 30 to 60 minutes;

[0033] Step 5: The temperature in the furnace (RH vacuum furnace) is operated at 700-900°C.

[0034] Step 4 includes: after the MFB multifunctional oxygen gun is lifted for 60 minutes, when the temperature in the furnace drops to 700°C, the gun is automatically lowered and ignited for 60 minutes. When the temperature in the furnace drops to 700°C, the gun is automatically lowered and ignited for 60 minutes, and the gas flow rate of the MFB multifunctional oxygen gun is set to 250Nm 3 / h, the oxygen flow rate is set to 180Nm 3 / h.

[0035] Step 4 also includes: when the MFB multifunctional oxygen gun is lifted for 30 minutes, when the temperature in the furnace drops to 800°C, the gun is automatically lowered and ignited for 30 minutes. When the temperature in the furnace drops to 800°C, the gun is automatically lowered and ignited for 30 minutes, and the gas flow rate of the MFB multifunctional oxygen gun is set to 220Nm 3 / h, the oxygen flow rate is set to 300Nm 3 / h.

[0036] After RH refining is completed by adopting the technical solution of the present invention, the RH top gun enters the automatic intermittent baking mode in the long-term standby state, and the energy gas and oxygen consumption of online baking is reduced by 50% without affecting normal production. The service life of the refractory materials of the RH refining furnace equipment is greatly improved.

[0037] Example 1:

[0038] The present invention provides a RH online automatic intermittent energy-saving baking control method, which is operated by the following steps:

[0039] First, after the RH vacuum furnace is finished smelting, the MFB multi-functional oxygen lance flame is required to keep warm in the standby state.

[0040] Furthermore, after smelting is completed and in standby mode, the temperature inside the furnace is raised to about 900 degrees Celsius, the MFB multifunctional oxygen lance is automatically raised, the energy medium is closed and the flame is extinguished, utilizing the principle that the RH vacuum furnace has good airtightness and slow heat dissipation;

[0041] Furthermore, in the first-level program, the MFB multi-function oxygen gun needs to be automatically controlled. After the gun is lifted, the time is automatically counted. After 1 hour of lifting the gun, the temperature in the furnace naturally drops to about 700°. The gun is automatically lowered and ignited for 1 hour. The gas is set to 250Nm 3 / h, oxygen setting 180Nm 3 / h, continue to raise the temperature in the furnace to 900 degrees Celsius;

[0042] Furthermore, the present invention utilizes a first-level computer automatic control program to automatically raise and lower the MFB multifunctional oxygen lance for baking, with a cycle interval of 60 minutes, so that the furnace temperature operates at 700-900 degrees Celsius. This not only meets the requirements for steelmaking, but also ensures the stability of the refractory material, while reducing energy consumption by 50%.

[0043] Table 1 Temperature inside the intermittent energy-saving baking furnace in the first embodiment

[0044] End of smelting Furnace temperature 0~60min 900～700° 60min~120min 700～900° 120min~180min 900～700° 120s~180s 700～900° After normal smelting 900° stable

[0045] As can be seen from Table 1, after the smelting is completed, the furnace temperature drops to 900 degrees without baking. After 1 hour, it drops to 700 degrees, and then starts baking for 60 minutes, and then returns to 900 degrees. Then the baking is stopped and the temperature drops to 700 degrees again, and then starts baking again for 60 minutes and rises to 900 degrees, with intermittent baking and heat preservation.

[0046] After normal steelmaking, cancel the MFB multi-function oxygen lance energy-saving baking mode on the first-level computer, change the automatic control to manual control, and restore to normal status;

[0047] Example 2:

[0048] The present invention provides a RH online automatic intermittent energy-saving baking control method, which is operated by the following steps:

[0049] First, after the RH vacuum furnace is finished smelting, the MFB multi-functional oxygen lance flame is required to keep warm in the standby state.

[0050] Furthermore, at the end of smelting, in standby mode, since the temperature of the molten steel reaches more than 1600 degrees Celsius, the temperature in the furnace is maintained at around 900 degrees Celsius at the end of smelting, the MFB multifunctional oxygen lance is automatically raised, and the flame is extinguished, utilizing the principle that the RH vacuum furnace has good sealing and slow heat dissipation;

[0051] Furthermore, in the first level program, the MFB multifunctional oxygen gun needs to be automatically controlled. After the gun is lifted, the timing is automatically turned on. After 30 minutes of lifting the gun, the gun is automatically lowered and ignited for 30 minutes. The gas is set to 220Nm 3 / h, oxygen setting 300Nm 3 / h, continue to raise the temperature in the furnace to 900 degrees Celsius;

[0052] Furthermore, the present invention utilizes a first-level computer automatic control program to automatically raise and lower the MFB multifunctional oxygen lance for baking, with a cycle interval of 30 minutes, so that the furnace temperature operates at 800-900 degrees Celsius, which not only meets the requirements for steelmaking, but also ensures the stable performance of the refractory material, while reducing energy consumption by 50%.

[0053] Table 2 Temperature in the intermittent energy-saving baking furnace of the second embodiment

[0054] End of smelting Furnace temperature 0~30min 900～800° 30min~60min 800～900° 60min~90min 900～800° 90 minutes to 120 minutes 800～900° After normal smelting 900° stable

[0055] As can be seen from Table 2, after the smelting is completed, the furnace temperature drops to 900 degrees without baking. After half an hour, it drops to 800 degrees, and then starts baking for 30 minutes and then starts baking for 60 minutes, and then returns to 900 degrees. Then the baking is stopped and the temperature drops to 800 degrees again, and then baking is started again and raised to 900 degrees, with intermittent baking and heat preservation.

[0056] Example 3:

[0057] The RH refining furnace in the third zone of Liuzhou Iron and Steel Converter Plant adopts the technical solution of this application, which mainly smelts cold-rolled base plates, ultra-low nitrogen, and carbon steel (steel grade DC01-1R). Its composition is shown in Table 3.

[0058] Table 3 DC01-1R steel composition

[0059] standard C Si Mn P S Cu Ni Cr Ti Alt As Internal Control ≤0.03 ≤0.03 0.1-0.25 ≤0.022 ≤0.015 ≤0.1 ≤0.1 ≤0.1 ≤0.01 0.02-0.05 ≤0.04 middle limit ≤0.03 ≤0.03 0.14-0.16 ≤0.02 ≤0.012 ≤0.1 ≤0.1 ≤0.1 ≤0.01 0.025-0.045 ≤0.04

[0060] The refining time is about 10 minutes, the temperature of the molten steel entering the station is about 1580℃, and the vacuum degree is about 1.258kPa.

[0061] The second is LGL5 automotive sheet steel and non-oriented electrical steel (steel grade LGL5-1R), the chemical composition of which is shown in Table 4.

[0062] Table 4 LGL5-1R steel composition

[0063] standard C Si Mn P S Ti Alt O N As Internal Control ≤0.0025 ≤0.03 ≤0.15 ≤0.015 ≤0.01 0.02-0.05 0.02-0.05 ≤0.003 ≤0.0028 ≤0.02 middle limit ≤0.0015 ≤0.03 ≤0.15 ≤0.015 ≤0.008 0.025-0.045 0.025-0.045 ≤0.003 ≤0.0028 ≤0.02

[0064] Refining time is 35 minutes, molten steel inlet temperature is 1620℃~1630℃, vacuum degree is about 0.322kPa, and the minimum vacuum degree is 10Pa. The proportion of special steel is over 40%. 11 vacuum tanks are tracked, and the outer casting of the offline immersion pipe is intact. The chrome-free brick lining is evenly corroded. The original brick thickness is 150mm, and the average residual thickness is 95~120mm. Figure 2 Judging from the residual thickness data, there is still room for improving the service life of the inserted tube. The erosion amount is only 28.6% of the new furnace, and the safety bottom line is 50%. According to the erosion amount, there is still room for use of 20 to 30 furnaces. At present, the residual thickness of this application's technical solution has no effect on the erosion of refractory materials and is within the range of conventional losses. Liugang No. 3 RH refining furnace has been put into use. The present invention has been running stably for 12 months, stabilizing the smelting of steel varieties, and the hit rate has been continuously improved. The management of equipment and the service life of refractory materials have been greatly improved. The stability of refractory performance is mainly reflected in the nitrogen increase level and decarburization effect. To verify the impact of the implementation of the present invention on the performance of refractory materials, the nitrogen increase in the refining of ultra-low carbon and ultra-low nitrogen steel grades was tracked and counted for 6 months. The carbon was controlled between 5 and 15 ppm, and the nitrogen was controlled between 13 and 27 ppm, both of which were in an extremely low range. The stable control of carbon and nitrogen elements in the RH refining process is beneficial to the smelting of high-end steel varieties.

[0065] In 2024, the operating rate of the three-zone RH furnace is about 60%, and the standby rate of the RH furnace is 40%. The annual standby time is: 365 days * 24 hours * 40% = 3504 hours;

[0066] The intermittent baking mode is expected to save 50% of oxygen and gas consumption. The gas and oxygen flow rates during vacuum chamber baking are both 200m 3 / h, if 80% of the standby time needs to be baked, the gas and oxygen consumption can be saved: 200m 3 / h*3504h*80%*50%=280320m 3 ;

[0067] Gas unit price 1.4 yuan / m 3 , oxygen price 0.42 yuan / m 3 , calculate the cost reduction, oxygen: 280320m 3 *0.42 yuan / m 3 ≈118,000. Gas: 280,320m 3 *1.4 yuan / m 3 ≈392,000. The two items combined are expected to reduce annual costs by approximately 510,000.

[0068] After RH refining is completed by adopting the technical solution of the present invention, the RH top gun enters the automatic intermittent baking mode in the long-term standby state, and the energy gas and oxygen consumption of online baking is reduced by 50% without affecting normal production. The service life of the refractory materials of the RH refining furnace equipment is greatly improved.

[0069] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. The various components of the present invention may be combined with each other without conflict, and any equivalent changes and modifications made by a person skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A RH online automatic intermittent energy-saving baking control method, characterized in that: The method comprises: Step 1: Connect the MFB multifunctional oxygen gun to the automatic control system; Step 2: After the RH vacuum furnace smelting is completed, the MFB multifunctional oxygen lance flame is used for heat preservation in the standby state; Step 3: After the smelting is completed, in standby mode, when the temperature inside the RH vacuum furnace is raised to 900°, the MFB multi-function oxygen lance is automatically raised, the energy medium is turned off and the flame is extinguished; Step 4: After lifting the MFB multifunctional oxygen gun for 30 to 60 minutes, when the temperature in the furnace drops to 700° to 800°, the gun is automatically lowered and ignited for baking for 30 to 60 minutes; Step 5: Keep the furnace temperature between 700 and 900°C.

2. The RH online automatic intermittent energy-saving baking control method according to claim 1, characterized in that: The energy media used by the MFB multifunctional oxygen gun are coal gas and oxygen.

3. The RH online automatic intermittent energy-saving baking control method according to claim 2, characterized in that: Step 4 includes: after the MFB multifunctional oxygen lance is lifted for 60 minutes, when the temperature in the furnace drops to 700°C, the lance is automatically lowered and ignited for baking for 60 minutes.

4. The RH online automatic intermittent energy-saving baking control method according to claim 2, characterized in that: Step 4 also includes: after the MFB multifunctional oxygen gun is lifted for 30 minutes, when the temperature in the furnace drops to 800°, the gun is automatically lowered and ignited for baking for 30 minutes.

5. The RH online automatic intermittent energy-saving baking control method according to claim 3, characterized in that: When the temperature in the furnace drops to 700°C, the gun is automatically lowered and ignited for 60 minutes. The gas flow rate of the MFB multi-function oxygen gun is set to 250Nm 3 / h, the oxygen flow rate is set to 180Nm 3 / h.

6. The RH online automatic intermittent energy-saving baking control method according to claim 4, characterized in that: When the temperature in the furnace drops to 800°C, the automatic lowering gun is ignited and baked for 30 minutes, and the gas flow rate of the MFB multi-function oxygen gun is set to 220Nm 3 / h, the oxygen flow rate is set to 300Nm 3 / h.

7. The RH online automatic intermittent energy-saving baking control method according to claim 1, characterized in that: After the RH vacuum furnace is finished smelting, the MFB multifunctional oxygen lance flame is used for heat preservation in the standby state; After smelting is completed, the furnace temperature is raised to 900°C in standby mode, the MFB multifunctional oxygen lance is automatically raised, the energy medium is turned off and the flame is extinguished; The MFB multifunctional oxygen gun is automatically controlled. When the MFB multifunctional oxygen gun is lifted, the time is automatically counted. One hour after the gun is lifted, the temperature in the furnace naturally drops to 700°. The gun is automatically lowered and ignited for baking for one hour. The gas flow is set to 220Nm 3 / h, oxygen flow rate is set to 300Nm 3 / h, continue to raise the temperature in the furnace to 900 degrees Celsius; The MFB multifunctional oxygen lance is automatically raised and lowered for baking, with a cycle interval of 60 minutes, so that the temperature in the furnace operates at 700-900 degrees Celsius.

8. The RH online automatic intermittent energy-saving baking control method according to claim 1, characterized in that: After the RH vacuum furnace is finished smelting, the MFB multifunctional oxygen lance flame is used for heat preservation in the standby state; After smelting is completed, the furnace temperature is raised to 900°C in standby mode, the MFB multifunctional oxygen lance is automatically raised, the energy medium is turned off and the flame is extinguished; For those who need automatic control of MFB multifunctional oxygen gun, the time will be automatically set after the MFB multifunctional oxygen gun is lifted. After 30 minutes of lifting the gun, the gun will be automatically lowered and ignited for 30 minutes. The gas flow rate is set to 220Nm 3 / h, the oxygen flow rate is set to 300Nm 3 / h, continue to raise the temperature in the furnace to 900 degrees Celsius; The MFB multifunctional oxygen gun is automatically raised and lowered for baking, with a cycle interval of 30 minutes, so that the temperature in the furnace operates at 800-900 degrees Celsius.

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