Steel ladle baking system and method based on alternate indentation combustion

Abstract

The invention discloses a steel ladle baking system and method based on alternate retraction combustion. The steel ladle baking system comprises a steel ladle, an alternate retraction device, a first burner and a second burner. The two burners are periodically and alternately lifted in the steel ladle through the alternate retraction device, so that the thermal shock to scrap steel in each area and each depth in the steel ladle is greatly improved, generated high-temperature flue gas even can be radiated to the bottom position of the lower layer of the steel ladle, and the preheating and soaking effects of the scrap steel are greatly improved compared with a traditional mode; the problems of waste steel condensation and uneven local baking of the steel ladle are greatly relieved, and meanwhile the service life of the steel ladle furnace lining is remarkably prolonged. In addition, the device has the advantages of being simple in structure, easy to operate, high in control precision, excellent in steel scrap soaking effect, low in investment and operation cost and the like.

Description

Technical Field

[0001] The invention relates to ladle baking preheating equipment and preheating technology, in particular to a ladle baking system and baking method based on alternating indentation combustion, belonging to the technical field of ladle baking preheating in steel production. Background Art

[0002] In the steelmaking process, the ladle is an important device used to receive high-temperature molten steel at the lower part of the discharge port of steelmaking equipment such as converters or electric furnaces, and transport the molten steel to the back-end refining process. A cold ladle at room temperature cannot directly receive molten steel at up to 2000 degrees Celsius, which will cause the refractory of the ladle to crack and break instantly. Therefore, before receiving molten steel, it is usually necessary to bake the ladle as a whole to above 1150 degrees Celsius with an external burner heat source, and then use a hot ladle to receive the molten steel. In the current market, some repurchased scrap steel has good quality and purity, and does not need to be smelted in a converter or electric furnace. It can generally be directly added to the back-end refining process. However, adding cold scrap steel directly to the refining will cause local cold zones in the furnace. Therefore, before the ladle is baked, adding an appropriate amount of scrap steel so that the ladle can be baked and preheated with the scrap steel, and then receive molten steel and go to the refining process together has become a common method to reduce costs and increase efficiency in the current industry market. However, at present, the ladle baking device that uses a large proportion of scrap steel has the following three major defects in the production process.

[0003] (1) Poor preheating and equalization of scrap steel: After a large proportion of scrap steel is added, it will accumulate into a thick column in the ladle, which will affect or even hinder the flame of the top burner from transferring heat downward. This will cause the scrap steel on the top to be baked to a molten state by the high-temperature flame, while the scrap steel at the bottom has not yet heated up in time. After the ladle receives the molten steel, a local cold zone will form at the bottom, causing the molten steel to condense. This will not only hinder the implementation of the argon bottom blowing process at the bottom of the ladle in the back-end refining process, but the condensed molten steel will also continue to adhere to the bottom of the ladle, resulting in a significant reduction in the number of times the ladle can be used.

[0004] (2) Poor ladle baking quality: As mentioned above, since the heat from the burner flame cannot be transmitted to the bottom of the ladle, the temperature at the bottom of the ladle cannot be effectively increased synchronously, which loses the original purpose of baking the ladle. When it suddenly comes into contact with ultra-high temperature molten steel, it is easy to cause cracking, breakage and other accidents.

[0005] (3) Short life of ladle lining: On the one hand, the quality of ladle baking deteriorates, and on the other hand, the molten steel will continue to stick to the bottom of the ladle, resulting in a significant shortening of the life cycle of the ladle lining, which greatly increases the production cost. Summary of the invention

[0006] In view of the problems in the prior art of adding scrap steel into the ladle for coordinated baking of the ladle, such as poor preheating and heat equalization effect of the scrap steel, poor ladle baking quality, short life of the ladle lining, the present invention provides a ladle baking system and baking method based on alternating indentation combustion. The present invention arranges an alternating indentation device on the top of the ladle, so that two burners are periodically and alternately raised and lowered in the ladle, which greatly improves the thermal shock on the scrap steel in various areas and depths in the ladle. The high-temperature flue gas of the flame can even radiate to the bottom of the lower layer of the ladle. The preheating and heat equalization effect of the scrap steel will be greatly improved compared with the traditional mode, so that the problems of scrap steel condensation and uneven local baking of the ladle are greatly alleviated, and the service life of the ladle lining is also significantly extended.

[0007] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are specifically described as follows:

[0008] According to a first embodiment of the present invention, a ladle baking system based on alternating indentation combustion is provided:

[0009] A ladle baking system based on alternating indentation combustion, the ladle baking system comprising a ladle, an alternating indentation device, a first burner and a second burner. The alternating indentation device is arranged at the top opening of the ladle. The first burner and the second burner are both arranged inside the ladle, and the bottom ends of the first burner and the second burner extend into the ladle to different depths, and the top ends of the first burner and the second burner are both connected to the alternating indentation device. The movement of the first burner and the second burner in the vertical direction is adjusted by the alternating indentation device, so that the depth of the bottom end of the first burner extending into the ladle and the depth of the bottom end of the second burner extending into the ladle change periodically and alternately. The upper ends of the first burner and the second burner are also independently connected to gas delivery pipelines with independently controlled flow rates.

[0010] Preferably, the alternating retracting device comprises a sealing cover plate, a bearing plate and a reciprocating retracting cylinder. The sealing cover plate is arranged at the top opening of the ladle, the bearing plate is arranged on the surface of the sealing cover plate, and the reciprocating retracting cylinder is arranged on the surface of the bearing plate. The top end of the first burner and the top end of the second burner are respectively connected to the two piston ends of the reciprocating retracting cylinder after passing through the sealing cover plate and the bearing plate in sequence, and the reciprocating retracting cylinder drives its two piston ends to perform periodic reciprocating motion, thereby driving the first burner and the second burner to perform periodic alternating lifting and lowering actions in the ladle.

[0011] Preferably, the reciprocating retracting cylinder comprises a cylinder, a piston plate, a piston rope, a first fixed pulley and a second fixed pulley. The cylinder is a closed chamber structure. The piston plate is movably arranged inside the cylinder and divides the inner cavity of the cylinder into a first air chamber and a second air chamber. The first fixed pulley is arranged in the first air chamber, and the second fixed pulley is arranged in the second air chamber. The piston rope passes through the piston plate and is fixedly connected to the piston plate. One end of the piston rope is connected to the first burner after bypassing the first fixed pulley, and the other end of the piston rope is connected to the second burner after bypassing the second fixed pulley. The first air chamber and the second air chamber are also independently connected to an air intake pipe and an exhaust pipe. By controlling the changes in the air pressure in the first air chamber and the second air chamber, the piston plate is made to perform periodic reciprocating motion in the cylinder, and then the first burner and the second burner are driven by the piston rope to perform periodic alternating lifting and lowering actions in the ladle.

[0012] Preferably, the alternating retracting device includes a sealing cover plate, a bearing plate, a first pulsating motor, a second pulsating motor, a first transmission mechanism and a first transmission mechanism. The sealing cover plate is arranged at the top opening of the ladle, the bearing plate is arranged on the surface of the sealing cover plate, and the first pulsating motor and the second pulsating motor are both arranged on the surface of the bearing plate. The top end of the first burner sequentially penetrates the sealing cover plate and the bearing plate and is connected to the first pulsating motor through the first transmission mechanism, and the top end of the second burner sequentially penetrates the sealing cover plate and the bearing plate and is connected to the second pulsating motor through the second transmission mechanism. The operation of the first pulsating motor and the second pulsating motor controls the first burner and the second burner to perform periodic alternating lifting and lowering actions in the ladle.

[0013] Preferably, the ladle baking system further comprises a self-rotating device, the self-rotating device comprising a rotating platform and a driving motor. The rotating platform is arranged at the bottom of the ladle, and the driving motor is arranged at the side of the rotating platform. The driving motor drives the rotating platform to rotate, thereby driving the ladle to rotate.

[0014] Preferably, the ladle baking system further comprises a spring weighing device, and the spring weighing device is arranged at the bottom of the rotating device.

[0015] Preferably, the ladle baking system also includes a control device, which is electrically connected to the alternating retraction device, the rotation device and the spring weighing device, and the working states of the alternating retraction device, the rotation device and the spring weighing device are regulated by the control device.

[0016] According to a second embodiment of the present invention, a method for baking a ladle is provided:

[0017] A ladle baking method or a ladle baking method using the ladle baking system based on alternating indentation combustion described in the first embodiment, the method comprising the following steps:

[0018] 1) Add scrap steel into the ladle, and calculate the scrap steel layer height in the ladle and the preheating coefficient when baking the ladle according to the amount of scrap steel added and its particle size.

[0019] 2) The depth of the burner is calculated based on the height of the scrap layer in the ladle. The rotation speed of the ladle, the pulse cycle of the burner's alternating rise and fall, the gas flow rate delivered to the burner, and the pulse equivalent of the burner gas are calculated based on the preheating coefficient.

[0020] 3) Parameters are set according to the burner's descending depth, the ladle's rotation speed, the burner's alternating lifting and lowering pulsation period, the gas flow delivered to the burner, and the burner gas pulsation equivalent, and the ladle is baked according to the set parameters until the ladle meets the requirements for holding molten steel.

[0021] Preferably, step 1) is specifically as follows: the total mass of the scrap steel in the ladle is measured by a spring weighing device and recorded as W, kg. Then:

[0022] The height H, m, of the scrap steel layer in the ladle is:

[0023] H=W / (ρ*3.14*R 2 ) (I).

[0024] The preheating coefficient β when baking the ladle, kJ / mm is:

[0025] β=(W*Cp*Tp) / D (II).

[0026] In formulas (I)-(II): ρ is the bulk density of the scrap steel, kg / m 3 R is the inner radius of the ladle, m. Cp is the average specific heat capacity of the scrap steel, kJ / (kg·℃). Tp is the average target temperature of the scrap steel to be preheated, ℃. D is the average particle size of the scrap steel, mm.

[0027] Preferably, step 2) is as follows: when the ladle is baked, the depth of the burner is recorded as h, m. The rotation speed of the ladle is recorded as V, r / min. The pulse cycle of the burner's alternating rise and fall is recorded as T, min. The gas flow rate delivered to the burner is recorded as Q, m 3 / min. The pulsation equivalent of the burner gas is recorded as Then we have:

[0028] h=λ*H (III).

[0029] V=a*β+b (IV).

[0030] T=c*β+d(V).

[0031] Q=(e*β3 +Cp*β) / u (VI).

[0032]

[0033] In formulas (III)-(VII): λ is the depth correction coefficient, which is 0.1-1; a is the rotation correction coefficient, (r·mm) / (kJ·min), which is 0.0001-0.01. b is the rotation correction constant, which is 0.01-1. c is the pulsation period correction coefficient, (min·mm) / kJ, which is 0.0001-0.01. d is the pulsation period correction constant, which is 0.01-1. e is the gas flow correction coefficient, mm 2 / (kJ·kg·℃), with a value of 0.001-0.1. u ​​is the calorific value of the gas, kJ / kg. z is the flow correction factor, (℃·mm·m 3 ) / (kJ·min), the value is 1. f is the pulsation equivalent correction coefficient.

[0034] It should be noted that all formulas in the present invention are obtained by fitting by the inventor based on experiments and engineering applications, and all calculations are numerical values ​​converted according to prescribed units, and are obtained by substituting the numerical values ​​after conversion into the formulas (after conversion of the units, only the numerical values ​​are substituted into the formulas for calculation, without substituting the units, and the units are only used to adjust the size of the numerical values).

[0035] In the present invention, since the traditional single-flame baking mode on the top of the ladle has a poor preheating effect on the baking of the ladle, the present invention changes the traditional single-flame baking mode on the top of the ladle into a double-flame baking mode provided by the double burners on the top of the ladle, and the upper and lower positions of the two burners (i.e., the depth of the ladle downward) and the gas flow rate are pulsatingly rotated according to a certain period. Through the pulsating alternating flame, the thermal radiation impact on the scrap steel in various areas and depths in the ladle is improved, so that the high temperature of the flame can directly penetrate to the scrap steel at the bottom layer of the ladle, so that the preheating and equalizing effects of the scrap steel will be greatly improved compared with the traditional mode, and the phenomenon of local cold zones caused by too low scrap steel temperature is effectively avoided. Since the uniformity of the preheating of the scrap steel is improved, the overall baking quality of the ladle is qualitatively improved, and the overall lining life of the ladle roaster is effectively extended.

[0036] In the present invention, an alternating retracting device is provided on the top of the ladle to control the periodic alternating lifting and lowering of two burners (the first burner and the second burner) in the ladle. The alternating retracting device includes a cover plate, a load-bearing plate, and a reciprocating retracting cylinder (or a pulsating motor group); through the periodic reciprocating motion of the reciprocating retracting cylinder or the alternating operation of the two pulsating motors in the pulsating motor group, the two burners are periodically driven to alternately rise and fall in the ladle (maintaining an up-and-down positional relationship) to meet the uniform heating requirements for scrap steel in the ladle.

[0037] In the present invention, the reciprocating retracting cylinder includes a cylinder, a piston plate, a piston rope, a first fixed pulley, and a second fixed pulley. The piston plate divides the cylinder into two independent air chambers, and the two independent air chambers are independently connected with an air inlet pipe and an exhaust pipe. By adjusting the air pressure changes in the two independent air chambers, the piston plate is reciprocated between the two air chambers. The piston rope passes through the piston plate and is fixedly connected to the piston plate, and the two ends of the piston rope are respectively turned through two fixed pulleys and then connected to the two burners downward. The reciprocating motion of the piston plate drives the two ends of the piston rope to perform periodic up and down lifting and lowering respectively, thereby driving the periodic alternating lifting and lowering motion of the two burners. Since the two burners are connected by the same piston rope, the one-up and one-down motion of the two burners is performed synchronously, that is, when one burner rises to the highest point, the other burner falls to the lowest point. It should be noted that in the present invention, the lowest point of the burner descent can be adjusted according to the actual working conditions, specifically by adjusting the air pressure difference in the two air chambers on both sides of the piston plate.

[0038] In the present invention, the pulsating motor group includes a first pulsating motor, a second pulsating motor, a first transmission mechanism and a second transmission mechanism. The upper part of the first burner is connected to the bearing plate through the first transmission mechanism, and the upper part of the second burner is connected to the bearing plate through the second transmission mechanism; the first pulsating motor drives the first transmission mechanism to adjust the lifting of the first burner, and the second pulsating motor drives the second transmission mechanism to adjust the lifting of the second burner. It should be noted that the first pulsating motor and the second pulsating motor are synchronously associated, that is, when the first pulsating motor drives the first burner to descend, the second motor synchronously drives the second burner to ascend; conversely, when the first pulsating motor drives the first burner to ascend, the second motor synchronously drives the second burner to descend. In other words, through the joint action of the first pulsating motor and the second pulsating motor, the periodic alternating lifting and lowering movements of the two burners in the ladle are controlled.

[0039] In the present invention, it should be noted that the two burners (the first burner and the second burner) generally transport gas through independent gas branches, that is, the gas transported by the main gas pipe is independently supplied to the two burners through two gas branches. A total gas flow valve is provided on the main gas pipe, and branch gas flow valves are provided on the two gas branches. According to the actual working conditions, the total gas delivery volume is adjusted by the total gas flow valve. At the same time, the gas flow delivered to the two burners is adjusted by the two branch gas flow valves. Generally, when the burner is descending in the ladle, the gas flow delivered to the burner gradually increases (when it descends to the lowest point, the gas flow delivered to the burner accounts for 60-95% of the total gas delivery flow), and when the burner is ascending in the ladle, the gas flow delivered to the burner gradually increases and decreases (when it rises to the highest point, the gas flow delivered to the burner accounts for 5-40% of the total gas delivery flow). By differentially controlling the gas flow rates in the two burners, the flame combustion intensity generated by the two burners changes significantly. The closer the burner is to the bottom scrap steel, the greater the flame combustion intensity, which is more conducive to baking and preheating the scrap steel. In addition, due to the difference in flame combustion intensity between the two burners, it is also beneficial to increase the flow rate of the flue gas in the ladle, which in turn helps to increase the flow of the warm flue gas in the scrap steel layer and improve the heat uniformity effect on the scrap steel.

[0040] In the present invention, a self-rotation device is also provided at the bottom of the ladle, and the self-rotation device includes a rotating table and a driving motor. The driving motor drives the rotating table to rotate, thereby driving the ladle to self-rotate. It should be noted that during the self-rotation of the ladle, the two burner devices do not rotate with the ladle (for example, the load-bearing plate and the sealing cover plate are connected by a movable bearing, and the sealing cover plate rotates with the ladle, but the load-bearing plate does not move. Or the sealing cover plate and the ladle are connected by a movable bearing, and the ladle rotates, but the sealing cover plate and the load-bearing plate do not move). In other words, while the two burners are periodically and alternately lifting and lowering the spray flames, the ladle and the scrap steel inside it rotate, thereby greatly improving the baking preheating of the scrap steel in different areas by the burner flame, making the burner preheating the scrap steel more uniform, and greatly improving the uniform heating effect of the scrap steel.

[0041] In the present invention, a spring weighing device is also provided at the bottom of the ladle, the purpose of which is to accurately obtain the weight of scrap steel added into the ladle before the ladle baking operation is carried out, thereby facilitating the control device to accurately adjust the parameters of various operations to ensure baking efficiency and safe operation of the system.

[0042] In the present invention, the control device has no fixed setting point, and can be set next to the ladle for control, or can be remotely controlled by a central control room, according to the actual working conditions, as long as it can meet the control function of various parameters during ladle baking. The control device of the present invention belongs to the category of mature parameter feedback adjustment control devices, and existing products can be directly purchased from the market, and corresponding parameters can be adjusted according to working conditions.

[0043] In the present invention, when the ladle is baked by the ladle baking system or ladle baking method of the present invention, after the crushed scrap steel is added into the ladle, the spring weighing device is first used to obtain the accurate amount of scrap steel added into the ladle, W, kg. And the bulk density of the scrap steel in the ladle, and then combined with the scrap steel particle size D, mm detected in the raw material field, the height H (m) of the scrap steel layer in the ladle during this ladle baking and the preheating coefficient β (kJ / mm) are calculated. The formula is as follows:

[0044] H=W / (ρ*3.14*R 2 ) (I).

[0045] β=(W*Cp*Tp) / D (II).

[0046] In formula (I)-formula (II): ρ is the bulk density of scrap steel, kg / m 3 R is the inner radius of the ladle, m. Cp is the average specific heat capacity of the scrap steel, kJ / (kg·℃). Tp is the average target temperature of the scrap steel to be preheated, ℃. D is the average particle size of the scrap steel, mm.

[0047] Furthermore, after obtaining the height H of the scrap steel layer in the ladle and the preheating coefficient β, the system will calculate the descending depth of the burner during the ladle baking process as h, m, the rotation speed of the ladle as V, r / min, the pulsation period of the alternate rise and fall of the burner as T, min, and the gas flow rate delivered to the burner as Q, m according to H and β. 3 / min and the pulsation equivalent of the burner gas is recorded as Their calculation formulas are as follows:

[0048] h=λ*H (III).

[0049] V=a*β+b (IV).

[0050] T=c*β+d(V).

[0051] Q=(e*β 3 +Cp*β) / u (VI).

[0052]

[0053] In formulas (III)-(VII): λ is the depth correction coefficient, which is 0.1-1; a is the rotation correction coefficient, (r·mm) / (kJ·min), which is 0.0001-0.01. b is the rotation correction constant, which is 0.01-1. c is the pulsation period correction coefficient, (min·mm) / kJ, which is 0.0001-0.01. d is the pulsation period correction constant, which is 0.01-1. e is the gas flow correction coefficient, mm 2 / (kJ·kg·℃), with a value of 0.001-0.1. u ​​is the calorific value of the gas, kJ / kg. z is the flow correction factor, (℃·mm·m 3 ) / (kJ·min), the value is 1. f is the pulsation equivalent correction coefficient.

[0054] In the present invention, the burner's descending depth h, the ladle's rotation speed V, the burner's alternating lifting and lowering pulsation period T, the gas flow Q delivered to the burner, and the burner gas's pulsation equivalent are obtained. After the parameter value is set, the control device will use it as the target value to automatically adjust the alternating retraction device, the rotation device and control the gas flow delivery until the h, V, T, Q, The gas is input from the main gas pipe at a flow rate of Q and is pulsated at a rate of After distribution, it is delivered to the two burners respectively (for example, if the current pulse equivalent is 3, it means that the gas flow rate of the first burner is 3 times that of the second burner, and if it is 0.3, it is 0.3 times). At the same time, the ladle rotates at a certain rotation speed V to ensure that all areas in the ladle are evenly baked by the flame. At this point, this operation is completed, and the system will intelligently implement the optimized large-proportion scrap steel ladle baking production based on the estimated value. It should be noted that the above description is only a preferred embodiment of the present invention, and conventional modifications and substitutions made without departing from the technical concept of the present invention should be included in the scope of the present invention.

[0055] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0056] 1: The present invention adds an alternating indentation device on the top of the ladle and distributes gas differentially to each burner that is periodically and alternately raised and lowered. The alternating flame improves the efficient preheating of scrap steel in various areas of the ladle, and the high-temperature flue gas generated by the flame can directly penetrate into the scrap steel layer, so that the preheating and equalizing effects of the scrap steel are greatly improved compared with the traditional mode, overcoming the problem of local cold zones caused by too low scrap steel temperature in the prior art.

[0057] 2: The present invention also adds a self-rotating device at the bottom of the ladle. Through the self-rotation of the ladle and the dynamic and static combination of the burner group that is upgraded only in the vertical direction, two changing flames are allowed to burn in different areas of the scrap steel layer pile, and at the same time, the penetration of high-temperature flue gas in the scrap steel layer is further enhanced, thereby improving the heat exchange efficiency, greatly alleviating the problems of scrap steel condensation and uneven local baking of the ladle, and at the same time, the service life of the ladle lining is also significantly extended.

[0058] 3: The present invention adopts a combination of an alternating indentation device and a ladle rotation device with a special structure, which improves the equalizing effect of the ladle and the scrap steel. It also has the advantages of simple structure, easy operation, high control accuracy, excellent equalizing effect of the scrap steel, and low investment and operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of the structure of the system of the present invention when the first burner is moving downward.

[0060] Figure 2 It is a structural schematic diagram of the second burner of the system of the present invention when it is moving downward.

[0061] Figure 3 It is an enlarged structural schematic diagram of the reciprocating retracting cylinder of the present invention.

[0062] Figure 4 It is an enlarged structural schematic diagram of the pulsating motor type alternating retracting device of the present invention.

[0063] Figure 5 It is an enlarged schematic diagram of the bottom of the ladle of the present invention.

[0064] Figure 6 Schematic diagram of control of the control device of the present invention.

[0065] Figure 7 The figure is a control logic flow chart of the ladle baking method of the present invention.

[0066] Figure numerals: 1: ladle; 2: alternating retracting device; 201: sealing cover plate; 202: load-bearing plate; 203: reciprocating retracting cylinder; 2031: cylinder; 2032: piston plate; 2033: piston rope; 2034: first fixed pulley; 2035: second fixed pulley; 204: first pulsating motor; 205: second pulsating motor; 206: first transmission mechanism; 207: second transmission mechanism; 3: first burner; 4: second burner; 5: rotation device; 501: rotating table; 502: driving motor; 6: spring weighing device; 7: control device. DETAILED DESCRIPTION

[0067] The technical solution of the present invention is illustrated below by way of example, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

[0068] A ladle baking system based on alternating indentation combustion, the ladle baking system comprises a ladle 1, an alternating indentation device 2, a first burner 3 and a second burner 4. The alternating indentation device 2 is arranged at the top opening of the ladle 1. The first burner 3 and the second burner 4 are both arranged inside the ladle 1, and the bottom ends of the first burner 3 and the second burner 4 extend into the ladle 1 to different depths, and the top ends of the first burner 3 and the second burner 4 are both connected to the alternating indentation device 2. The movement of the first burner 3 and the second burner 4 in the vertical direction is adjusted by the alternating indentation device 2, so that the depth of the bottom end of the first burner 3 extending into the ladle 1 and the depth of the bottom end of the second burner 4 extending into the ladle 1 change periodically and alternately. The upper ends of the first burner 3 and the second burner 4 are also independently connected to gas delivery pipelines with independently controlled flow rates.

[0069] Preferably, the alternating retracting device 2 comprises a sealing cover plate 201, a bearing plate 202 and a reciprocating retracting cylinder 203. The sealing cover plate 201 is arranged at the top opening of the ladle 1, the bearing plate 202 is arranged on the surface of the sealing cover plate 201, and the reciprocating retracting cylinder 203 is arranged on the surface of the bearing plate 202. The top end of the first burner 3 and the top end of the second burner 4 are respectively connected to the two piston ends of the reciprocating retracting cylinder 203 after passing through the sealing cover plate 201 and the bearing plate 202 in sequence. The reciprocating retracting cylinder 203 drives its two piston ends to perform periodic reciprocating motion, thereby driving the first burner 3 and the second burner 4 to perform periodic alternating lifting and lowering actions in the ladle 1.

[0070] Preferably, the reciprocating retracting cylinder 203 comprises a cylinder 2031, a piston plate 2032, a piston rope 2033, a first fixed pulley 2034 and a second fixed pulley 2035. The cylinder 2031 is a closed chamber structure. The piston plate 2032 is movably arranged inside the cylinder 2031, and divides the inner cavity of the cylinder 2031 into a first air chamber and a second air chamber. The first fixed pulley 2034 is arranged in the first air chamber, and the second fixed pulley 2035 is arranged in the second air chamber. The piston rope 2033 penetrates the piston plate 2032 and is fixedly connected to the piston plate 2032. One end of the piston rope 2033 bypasses the first fixed pulley 2034 and is connected to the first burner 3. The other end of the piston rope 2033 bypasses the second fixed pulley 2035 and is connected to the second burner 4. The first air chamber and the second air chamber are also independently connected with an intake pipe and an exhaust pipe. By controlling the changes in the air pressure in the first air chamber and the second air chamber, the piston plate 2032 is caused to perform periodic reciprocating motion in the cylinder 2031, and then the first burner 3 and the second burner 4 are driven to perform periodic alternating lifting and lowering motions in the ladle 1 through the piston rope 2033.

[0071] Preferably, the alternating retracting device 2 comprises a sealing cover plate 201, a bearing plate 202, a first pulsating motor 204, a second pulsating motor 205, a first transmission mechanism 206 and a second transmission mechanism 207. The sealing cover plate 201 is arranged at the top opening of the ladle 1, the bearing plate 202 is arranged on the surface of the sealing cover plate 201, and the first pulsating motor 204 and the second pulsating motor 205 are both arranged on the surface of the bearing plate 202. The top end of the first burner 3 sequentially penetrates the sealing cover plate 201 and the bearing plate 202 and is connected to the first pulsating motor 204 through the first transmission mechanism 206, and the top end of the second burner 4 sequentially penetrates the sealing cover plate 201 and the bearing plate 202 and is connected to the second pulsating motor 205 through the second transmission mechanism 207. The operation of the first pulsating motor 204 and the second pulsating motor 205 controls the first burner 3 and the second burner 4 to perform periodic alternating lifting and lowering actions in the ladle 1.

[0072] Preferably, the ladle baking system further comprises a self-rotating device 5, which comprises a rotating table 501 and a driving motor 502. The rotating table 501 is arranged at the bottom of the ladle 1, and the driving motor 502 is arranged at the side of the rotating table 501. The driving motor 502 drives the rotating table 501 to rotate, thereby driving the ladle 1 to rotate.

[0073] Preferably, the ladle baking system further comprises a spring weighing device 6 , and the spring weighing device 6 is arranged at the bottom of the rotating device 5 .

[0074] Preferably, the ladle baking system also includes a control device 7, which is electrically connected to the alternating retraction device 2, the rotation device 5 and the spring weighing device 6, and the working states of the alternating retraction device 2, the rotation device 5 and the spring weighing device 6 are regulated by the control device 7.

[0075] Example 1

[0076] like Figure 1-6 As shown, a ladle baking system based on alternating indentation combustion comprises a ladle 1, an alternating indentation device 2, a first burner 3 and a second burner 4. The alternating indentation device 2 is arranged at the top opening of the ladle 1. The first burner 3 and the second burner 4 are both arranged inside the ladle 1, and the bottom ends of the first burner 3 and the second burner 4 extend into the ladle 1 to different depths, and the top ends of the first burner 3 and the second burner 4 are both connected to the alternating indentation device 2. The movement of the first burner 3 and the second burner 4 in the vertical direction is adjusted by the alternating indentation device 2, so that the depth of the bottom end of the first burner 3 extending into the ladle 1 and the depth of the bottom end of the second burner 4 extending into the ladle 1 change periodically and alternately. The upper ends of the first burner 3 and the second burner 4 are also independently connected to gas delivery pipelines with independently controlled flow rates.

[0077] Example 2

[0078] Example 1 is repeated, except that the alternating retracting device 2 includes a sealing cover plate 201, a bearing plate 202 and a reciprocating retracting cylinder 203. The sealing cover plate 201 is arranged at the top opening of the ladle 1, the bearing plate 202 is arranged on the surface of the sealing cover plate 201, and the reciprocating retracting cylinder 203 is arranged on the surface of the bearing plate 202. The top end of the first burner 3 and the top end of the second burner 4 are respectively connected to the two piston ends of the reciprocating retracting cylinder 203 after passing through the sealing cover plate 201 and the bearing plate 202 in sequence. The reciprocating retracting cylinder 203 drives its two piston ends to perform periodic reciprocating motion, thereby driving the first burner 3 and the second burner 4 to perform periodic alternating lifting and lowering actions in the ladle 1.

[0079] Example 3

[0080] Repeat Example 2, except that the reciprocating retracting cylinder 203 includes a cylinder 2031, a piston plate 2032, a piston rope 2033, a first fixed pulley 2034 and a second fixed pulley 2035. The cylinder 2031 is a closed chamber structure. The piston plate 2032 is movably arranged inside the cylinder 2031, and divides the inner cavity of the cylinder 2031 into a first air chamber and a second air chamber. The first fixed pulley 2034 is arranged in the first air chamber, and the second fixed pulley 2035 is arranged in the second air chamber. The piston rope 2033 penetrates the piston plate 2032 and is fixedly connected to the piston plate 2032. One end of the piston rope 2033 bypasses the first fixed pulley 2034 and is connected to the first burner 3, and the other end of the piston rope 2033 bypasses the second fixed pulley 2035 and is connected to the second burner 4. The first air chamber and the second air chamber are also independently connected with an intake pipe and an exhaust pipe. By controlling the changes in the air pressure in the first air chamber and the second air chamber, the piston plate 2032 is caused to perform periodic reciprocating motion in the cylinder 2031, and then the first burner 3 and the second burner 4 are driven to perform periodic alternating lifting and lowering motions in the ladle 1 through the piston rope 2033.

[0081] Example 4

[0082] Example 3 is repeated, except that the alternating retracting device 2 includes a sealing cover plate 201, a bearing plate 202, a first pulsating motor 204, a second pulsating motor 205, a first transmission mechanism 206, and a second transmission mechanism 207. The sealing cover plate 201 is arranged at the top opening of the ladle 1, the bearing plate 202 is arranged on the surface of the sealing cover plate 201, and the first pulsating motor 204 and the second pulsating motor 205 are both arranged on the surface of the bearing plate 202. The top end of the first burner 3 sequentially penetrates the sealing cover plate 201 and the bearing plate 202 and is connected to the first pulsating motor 204 through the first transmission mechanism 206, and the top end of the second burner 4 sequentially penetrates the sealing cover plate 201 and the bearing plate 202 and is connected to the second pulsating motor 205 through the second transmission mechanism 207. The operation of the first pulsating motor 204 and the second pulsating motor 205 controls the first burner 3 and the second burner 4 to perform periodic alternating lifting and lowering actions in the ladle 1.

[0083] Example 5

[0084] Example 4 is repeated, except that the ladle baking system further includes a self-rotating device 5, and the self-rotating device 5 includes a rotating table 501 and a driving motor 502. The rotating table 501 is arranged at the bottom of the ladle 1, and the driving motor 502 is arranged at the side of the rotating table 501. The driving motor 502 drives the rotating table 501 to rotate, thereby driving the ladle 1 to rotate.

[0085] Example 6

[0086] Example 5 is repeated, except that the ladle baking system further includes a spring weighing device 6 , and the spring weighing device 6 is arranged at the bottom of the rotating device 5 .

[0087] Example 7

[0088] Example 6 is repeated, except that the ladle baking system also includes a control device 7, and the control device 7 is electrically connected to the alternating retraction device 2, the rotation device 5 and the spring weighing device 6. The working states of the alternating retraction device 2, the rotation device 5 and the spring weighing device 6 are regulated by the control device 7.

[0089] Example 8

[0090] A method for ladle baking using the system described in Example 7 comprises the following steps:

[0091] 1) Adding scrap steel into the ladle 1, and calculating the height of the scrap steel layer in the ladle 1 and the preheating coefficient when baking the ladle 1 according to the amount of scrap steel added into the ladle 1 and its particle size.

[0092] 2) The burner's descending depth is calculated based on the scrap steel layer height in the ladle 1. The rotation speed of the ladle 1, the pulsation cycle of the burner's alternate rise and fall, the gas flow rate delivered to the burner, and the pulsation equivalent of the burner gas are calculated based on the preheating coefficient.

[0093] 3) Parameters are set according to the burner's descending depth, the rotation speed of the ladle 1, the pulsation period of the burner's alternating rise and fall, the gas flow rate supplied to the burner, and the pulsation equivalent of the burner gas, and the ladle 1 is baked according to the set parameters until the ladle 1 meets the requirements for holding molten steel.

[0094] Example 9

[0095] Example 8 is repeated, except that step 1) is specifically as follows: the total mass of the scrap steel in the ladle 1 is detected by the spring weighing device 6 and recorded as W, kg. Then:

[0096] The height H, m, of the scrap steel layer in the ladle 1 is:

[0097] H=W / (ρ*3.14*R 2 )(I).

[0098] The preheating coefficient β, kJ / mm, for baking ladle 1 is:

[0099] β = (W*Cp*Tp) / D(II).

[0100] In formulas (I)-(II): ρ is the bulk density of the scrap steel, kg / m 3 R is the inner radius of the ladle, m. Cp is the average specific heat capacity of the scrap steel, kJ / (kg·℃). Tp is the average target temperature of the scrap steel to be preheated, ℃. D is the average particle size of the scrap steel, mm.

[0101] Example 10

[0102] Example 9 is repeated, except that step 2) is specifically as follows: the depth of the burner when the ladle 1 is baked is recorded as h, m. The rotation speed of the ladle 1 is recorded as V, r / min. The pulse period of the alternate rise and fall of the burner is recorded as T, min. The gas flow rate delivered to the burner is recorded as Q, m 3 / min. The pulsation equivalent of the burner gas is recorded as Then we have:

[0103] h=λ*H (III).

[0104] V=a*β+b (IV).

[0105] T=c*β+d(V).

[0106] Q=(e*β 3+Cp*β) / u (VI).

[0107]

[0108] In formulas (III)-(VII): λ is the depth correction factor. a is the rotation correction factor, (r·mm) / (kJ·min). b is the rotation correction constant. c is the pulsation period correction factor, (min·mm) / kJ. d is the pulsation period correction constant. e is the gas flow correction factor, mm 2 / (kJ·kg·℃). u is the calorific value of the gas, kJ / kg. z is the flow correction factor, (℃·mm·m 3 ) / (kJ·min), the value is 1; f is the pulsation equivalent correction coefficient.

[0109] Method Example 1

[0110] The ladle is baked using the system described in Example 7 and the method described in Example 10, wherein: the mass of the empty ladle 1 is 40000 kg; the height of the ladle 1 is 4 m; the loading capacity of the scrap steel detected by the spring weighing device 6 is 8000 kg; the average particle size D of the scrap steel is 180 mm;

[0111] The average specific heat capacity of scrap steel is Cp = 0.72 kJ / (kg·℃); the bulk density of scrap steel is ρ = 1000 kg / m 3 ; The inner radius of the ladle R = 1.5m; The target temperature of the scrap steel to be preheated Tp = 800°C; Then, according to formula (I), the height H of the scrap steel layer in the ladle 1 is calculated as:

[0112] H=W / (ρ*3.14*R 2 )=8000÷1000÷3.14÷1.5÷1.5=1.13m

[0113] The preheating coefficient β when baking the ladle 1 is calculated according to formula (II):

[0114] β=(W*Cp*Tp) / D=8000×0.72×800÷180=25600kJ / mm

[0115] According to the height H of the scrap steel layer in the ladle 1 and the depth correction coefficient λ=0.5 under the present working condition, the descending depth h of the burner is calculated according to formula (III):

[0116] h=λ*H=0.5×1.13=0.565m

[0117] According to the preheating coefficient β when the ladle 1 is baked and under the present working condition, the rotation correction coefficient a=0.0001; the rotation correction constant b=0.04, the rotation speed V of the ladle 1 is calculated according to formula (IV):

[0118] V=a*β+b=0.0001×25600+0.04=2.6r / min

[0119] According to the preheating coefficient β when the ladle 1 is baked and under the present working condition, the pulsation period correction coefficient c=0.0001; the pulsation period correction constant d=1, the pulsation period T of the alternate lifting and lowering of the burner is calculated according to formula (V):

[0120] T=c*β+d=0.0001×25600+1=3.56min

[0121] According to the preheating coefficient β when the ladle 1 is baked and the gas flow correction coefficient e=0.001 and the gas calorific value u=33000 kJ / kg under this working condition, the gas flow Q delivered to the burner is calculated according to formula (VI):

[0122] Q=(e*β 2 +Cp*β) / u=(0.001×25600 2 +0.72×25600)÷33000=20.42m 3 / min

[0123] According to the rotation speed of the ladle 1, the gas flow rate delivered to the burner and the pulsation equivalent correction factor f=1 under this working condition, the pulsation equivalent of the burner gas is calculated according to formula (VII): for:

[0124]

Claims

1. A ladle baking system based on alternating indentation combustion, characterized in that: The ladle baking system comprises a ladle (1), an alternating indentation device (2), a first burner (3) and a second burner (4); the alternating indentation device (2) is arranged at the top opening of the ladle (1); the first burner (3) and the second burner (4) are both arranged inside the ladle (1), and the bottom ends of the first burner (3) and the second burner (4) extend into the ladle (1) to different depths, and the top ends of the first burner (3) and the second burner (4) are both connected to the alternating indentation device (2); the movement of the first burner (3) and the second burner (4) in the vertical direction is adjusted by the alternating indentation device (2), so that the depth of the bottom end of the first burner (3) extending into the ladle (1) and the depth of the bottom end of the second burner (4) extending into the ladle (1) change periodically and alternately; the upper ends of the first burner (3) and the second burner (4) are also independently connected to gas delivery pipelines with independently controlled flow rates.

2. The ladle baking system according to claim 1, characterized in that: The alternating retraction device (2) comprises a sealing cover plate (201), a bearing plate (202) and a reciprocating retraction cylinder (203); the sealing cover plate (201) is arranged at the top opening of the ladle (1), the bearing plate (202) is arranged on the surface of the sealing cover plate (201), and the reciprocating retraction cylinder (203) is arranged on the surface of the bearing plate (202); the top end of the first burner (3) and the top end of the second burner (4) are respectively connected to the two piston ends of the reciprocating retraction cylinder (203) after passing through the sealing cover plate (201) and the bearing plate (202); the reciprocating retraction cylinder (203) drives its two piston ends to perform periodic reciprocating motion, thereby driving the first burner (3) and the second burner (4) to perform periodic alternating lifting and lowering actions in the ladle (1).

3. The ladle baking system according to claim 2, characterized in that: The reciprocating retracting cylinder (203) comprises a cylinder (2031), a piston plate (2032), a piston rope (2033), a first fixed pulley (2034) and a second fixed pulley (2035); the cylinder (2031) is a closed chamber structure; the piston plate (2032) is movably arranged inside the cylinder (2031) and divides the inner cavity of the cylinder (2031) into a first air chamber and a second air chamber; the first fixed pulley (2034) is arranged in the first air chamber, and the second fixed pulley (2035) is arranged in the second air chamber; the piston rope (2033) passes through the piston plate (2032) and is connected to the piston plate (203 2) fixedly connected, one end of the piston rope (2033) passes around the first fixed pulley (2034) and is connected to the first burner (3), and the other end of the piston rope (2033) passes around the second fixed pulley (2035) and is connected to the second burner (4); the first air chamber and the second air chamber are also independently connected to an air inlet pipe and an exhaust pipe respectively; by controlling the change of air pressure in the first air chamber and the second air chamber, the piston plate (2032) is caused to perform periodic reciprocating motion in the cylinder (2031), and then the first burner (3) and the second burner (4) are driven by the piston rope (2033) to perform periodic alternating lifting and lowering actions in the ladle (1).

4. The ladle baking system according to claim 1, characterized in that: The alternating retraction device (2) comprises a sealing cover plate (201), a bearing plate (202), a first pulsating motor (204), a second pulsating motor (205), a first transmission mechanism (206) and a second transmission mechanism (207); the sealing cover plate (201) is arranged at the top opening of the ladle (1), the bearing plate (202) is arranged on the surface of the sealing cover plate (201), and the first pulsating motor (204) and the second pulsating motor (205) are both arranged on the surface of the bearing plate (202); the top end of the first burner (3) After sequentially penetrating the sealing cover plate (201) and the bearing plate (202), the first transmission mechanism (206) is connected to the first pulsating motor (204); the top end of the second burner (4) sequentially penetrates the sealing cover plate (201) and the bearing plate (202), and is connected to the second pulsating motor (205) through the second transmission mechanism (207); the operation of the first pulsating motor (204) and the second pulsating motor (205) controls the first burner (3) and the second burner (4) to perform periodic alternating lifting and lowering actions in the ladle (1).

5. The ladle baking system according to any one of claims 1 to 4, characterized in that: The ladle baking system also includes a rotation device (5), the rotation device (5) including a rotating table (501) and a driving motor (502); the rotating table (501) is arranged at the bottom of the ladle (1), and the driving motor (502) is arranged on the side of the rotating table (501); the driving motor (502) drives the rotating table (501) to rotate, thereby driving the ladle (1) to rotate.

6. The ladle baking system according to claim 5, characterized in that: The ladle baking system also includes a spring weighing device (6), and the spring weighing device (6) is arranged at the bottom of the rotation device (5).

7. The ladle baking device according to claim 6, characterized in that: The ladle baking system also includes a control device (7), which is electrically connected to the alternating retracting device (2), the rotating device (5), and the spring weighing device (6). The control device (7) is used to regulate the working states of the alternating retracting device (2), the rotating device (5), and the spring weighing device (6).

8. A ladle baking method or a ladle baking method using the ladle baking system according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: 1) adding scrap steel into a ladle (1), and calculating the height of the scrap steel layer in the ladle (1) and the preheating coefficient when baking the ladle (1) according to the amount of scrap steel added into the ladle (1) and its particle size; 2) calculating the depth of the burner's descent according to the height of the scrap steel layer in the ladle (1); calculating the rotation speed of the ladle (1), the pulsation period of the burner's alternating rise and fall, the gas flow rate supplied to the burner, and the pulsation equivalent of the burner gas when the ladle (1) is baked according to the preheating coefficient; 3) Parameters are set according to the depth of the burner's descent, the rotation speed of the ladle (1), the pulsation period of the burner's alternating ascent and descent, the gas flow delivered to the burner, and the pulsation equivalent of the burner gas, and the ladle (1) is baked according to the set parameters until the ladle (1) meets the requirements for receiving molten steel.

9. The method according to claim 8, characterized in that: Step 1) specifically comprises: using a spring weighing device (6) to detect and obtain the total mass of scrap steel in the ladle (1), which is recorded as W, kg; then: The height H, m, of the scrap layer in the ladle (1) is: H=W / (ρ*3.14*R 2 (I); The preheating coefficient β, kJ / mm, for baking the ladle (1) is: β=(W*Cp*Tp) / D(II); In formulas (I)-(II): ρ is the bulk density of the scrap steel, kg / m 3 ; R is the inner radius of the ladle, m; Cp is the average specific heat capacity of the scrap steel, kJ / (kg·℃); Tp is the average target temperature of the scrap steel for preheating, ℃; D is the average particle size of the scrap steel, mm.

10. The method according to claim 9, characterized in that: Step 2) is specifically as follows: when the ladle (1) is baked, the depth of the burner's descent is recorded as h, m; the rotation speed of the ladle (1) is recorded as V, r / min; the pulse cycle of the burner's alternating rise and fall is recorded as T, min; the gas flow rate delivered to the burner is recorded as Q, m 3 / min; the pulsation equivalent of the burner gas is recorded as Then we have: h = λ*H(III); V = a*β+b(IV); T = c*β + d(V); Q=z*(e*β 3 +Cp*β) / u(VI); In formulas (III)-(VII): λ is the depth correction coefficient, which is 0.1-1; a is the rotation correction coefficient, (r·mm) / (kJ·min), which is 0.0001-0.01; b is the rotation correction constant, which is 0.01-1; c is the pulsation period correction coefficient, (min·mm) / kJ, which is 0.0001-0.01; d is the pulsation period correction constant, which is 0.01-1; e is the gas flow correction coefficient, mm 2 / (kJ·kg·℃), with a value of 0.001-0.1; u is the calorific value of the gas, kJ / kg; z is the flow correction coefficient, (℃·mm·m 3 ) / (kJ·min), the value is 1; f is the pulsation equivalent correction coefficient.

Images