A furnace method

Abstract

The application relates to the technical field of converter steelmaking, in particular to a furnace drying method. The method comprises the following steps: performing slag splashing protection operation on three continuous furnace times before a converter is planned to be shut down, and then performing furnace shutdown; performing furnace drying operation on the converter after the furnace is shut down, and controlling oxygen flow in the furnace drying operation; wherein the furnace drying operation comprises the following steps: adding coke with a first adding amount into the converter after the furnace is shut down before ignition; performing first furnace drying operation on the converter with the first adding amount of coke, controlling the time of the first furnace drying operation, and then performing furnace shaking operation; performing second furnace drying operation on the converter after the furnace shaking operation, and adding remaining coke in batches; wherein the oxygen lance height is adjusted after each batch of the remaining coke is added. The application solves the technical problem that coke is stuck to the bottom of the furnace after the furnace is dried, so that the quality of molten steel in the later smelting is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of converter steelmaking, and particularly relates to a furnace drying method. BACKGROUND

[0002] The converter equipped with a dry dedusting system usually needs to be dried before long-term shutdown or resumption of production after repair. The high-temperature flue gas generated by the oxygen gun blowing oxygen combustion is used to preheat the electric dust collector, so that the internal environment temperature of the electric dust collector is increased to above 70-80 DEG C, so as to ensure the stability of the electric dust collector.

[0003] At present, in the drying operation process, the coke is difficult to completely burn, and at the same time, the slag layer of the furnace lining will melt and fall off due to the continuous oxygen supply. The molten residue and unburned coke are often directly adhered to the furnace bottom, causing the furnace bottom to rise, and also blocking the converter bottom blowing hole, which seriously affects the blowing process control and end point control of the normal smelting furnace after drying. SUMMARY

[0004] The present application provides a drying method to solve the technical problem of coke sticking to the furnace bottom after drying.

[0005] In a first aspect, the present application provides a drying method, which comprises:

[0006] The slag protection operation is performed on the three consecutive furnace times before the converter is planned to be shut down, and then the converter is shut down;

[0007] The drying operation is performed on the converter after shutdown, and the oxygen flow during the drying operation is controlled; wherein the drying operation comprises:

[0008] The coke with a first addition amount is added to the converter after shutdown before ignition;

[0009] The first drying operation is performed on the converter with the first addition amount of coke, and the time of the first drying operation is controlled, and then the furnace shaking operation is performed;

[0010] The second drying operation is performed on the converter after the furnace shaking operation, and the remaining coke is added in batches; wherein the oxygen lance height is adjusted after each batch of the remaining coke is added.

[0011] Optionally, the slag protection operation on the three consecutive furnace times before the converter is planned to be shut down comprises:

[0012] The slag protection time of the third furnace before shutdown is <3 min, the slag protection time of the second furnace before shutdown is <2 min, and the slag protection time of the first furnace before shutdown is 0 min.

[0013] Optionally, the three consecutive furnace operations before the planned shutdown of the converter are performed by slag splashing protection operation, comprising:

[0014] The three consecutive furnace operations before the planned shutdown of the converter are performed by slag splashing protection operation; wherein when the first furnace before the shutdown is operated by slag pouring operation, the furnace opening is kept downward for more than 1 min after the slag pouring is completed.

[0015] Optionally, the first addition amount is 980-1200 kg.

[0016] Optionally, the time of the first furnace drying operation is 15-25 min.

[0017] Optionally, the second furnace drying operation is performed on the converter after the rocking furnace operation, and the remaining coke is added in batches, comprising:

[0018] The second furnace drying operation is performed on the converter after the rocking furnace operation, and 150-250 kg of coke is added at the beginning of the second furnace drying operation,

[0019] and 150-250 kg of coke is added every 8 min during the second furnace drying operation.

[0020] Optionally, after each batch of the remaining coke is added, the oxygen lance height is adjusted, comprising: after each batch of the remaining coke is added, the oxygen lance height is adjusted according to H-(H-200)-H; wherein H represents the initial height of the oxygen lance.

[0021] Optionally, the oxygen flow rate is 12000 m 3 / h-14000 m 3 / h.

[0022] Optionally, the rocking furnace operation comprises: rocking the furnace backward to-60°, and then rocking the furnace forward to 90° to perform the rocking furnace operation.

[0023] Optionally, the number of times of the rocking furnace operation is 2-3 times.

[0024] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0025] The furnace drying method provided by the embodiments of the present application adjusts the slag splashing protection operation before the shutdown, optimizes the addition mode of the coke, and controls the oxygen lance, so as to realize efficient combustion of the coke, reduce the excess of the coke, and finally achieve the purpose of preventing the coke from sticking to the bottom of the furnace after the furnace drying. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced as follows. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0028] Figure 1 A flowchart of a furnace baking method provided by the embodiments of the present application. DETAILED DESCRIPTION

[0029] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of the present application.

[0030] The various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is only for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the described range has specifically disclosed all possible sub-ranges and single values within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the described range, such as 1, 2, 3, 4, 5 and 6, which applies to any range. In addition, whenever a numerical range is indicated in this document, it refers to any cited number (fraction or integer) within the indicated range.

[0031] In the present application, the orientation words such as "upper" and "lower" are specifically the directions of the drawing surface in the drawings unless otherwise stated. In addition, in the description of the present application, the terms "include", "contain" and the like mean "include but not limited to". In the present text, the relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. In the present text, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the cases of A alone, A and B together, and B alone. Wherein A, B can be singular or plural. In the present text, "at least one" means one or more, and "multiple" means two or more. "At least one", "at least one of the following" or the like means any combination of the items, including single item or any combination of multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can represent a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple.

[0032] Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0033] In a first aspect, the present application provides a furnace drying method, please refer to Figure 1 The method of the present application is suitable for a 210-ton converter to prevent coke from sticking to the bottom of the 210-ton converter after drying the furnace, and the method comprises:

[0034] S1, performing slag splashing for furnace protection operation on the three consecutive furnace times before the planned shutdown of the converter, and then performing shutdown;

[0035] In some embodiments, the slag splashing for furnace protection operation on the three consecutive furnace times before the planned shutdown of the converter comprises:

[0036] The slag splashing for furnace protection time of the third furnace before shutdown is <3 min, the slag splashing for furnace protection time of the second furnace before shutdown is <2 min, and the slag splashing for furnace protection time of the first furnace before shutdown is 0 min.

[0037] In the embodiments of the present application, the principles of slag splashing and protecting the furnace before shutdown are formulated, the slag splashing time is appropriately shortened, and the thickness of the slag splashing layer of the converter is reduced, so as to reduce the amount of molten residue in the furnace heating process. The slag splashing and protecting the furnace is controlled for the first three consecutive furnace times before the planned shutdown of the converter (for example, repair or long-term shutdown), and the positive effects of the slag splashing and protecting the furnace for the first three consecutive furnace times before the planned shutdown of the converter are: by shortening the slag splashing and protecting the furnace time or not performing the slag splashing and protecting the furnace, the thickness of the slag splashing layer of the furnace lining before the shutdown is thin, and the total amount of molten residue in the furnace heating process is reduced. Specifically, the slag splashing and protecting the furnace time of the third furnace before the shutdown can be 2.8 min, 2.5 min, 2.0 min, etc., and the slag splashing and protecting the furnace time of the second furnace before the shutdown can be 1.8 min, 1.5 min, 1.2 min, etc.

[0038] In some embodiments, the slag splashing and protecting the furnace for the first three consecutive furnace times before the planned shutdown of the converter comprises:

[0039] The slag splashing and protecting the furnace is performed for the first three consecutive furnace times before the planned shutdown of the converter; wherein when the first furnace before the shutdown performs the slag removal operation, the furnace mouth is kept downward for more than 1 min after the slag removal is completed.

[0040] In the embodiments of the present application, when the first furnace before the shutdown performs the slag removal operation, the furnace mouth is kept downward for more than 1 min after the slag removal is completed, so as to ensure that the residual slag in the furnace is completely removed. Specifically, when the first furnace before the shutdown performs the slag removal operation, the time for keeping the furnace mouth downward after the slag removal is completed can be 1.1 min, 1.5 min, 1.8 min, etc.

[0041] S2, performing a furnace heating operation on the converter after the shutdown, and controlling the oxygen flow rate in the furnace heating operation; wherein the furnace heating operation comprises:

[0042] Before ignition, a first amount of coke is added to the converter after the shutdown;

[0043] Performing a first furnace heating operation on the converter with the first amount of coke, and controlling the time of the first furnace heating operation, and then performing a furnace shaking operation;

[0044] Performing a second furnace heating operation on the converter after the furnace shaking operation, and adding the remaining coke in batches; wherein after adding each batch of the remaining coke, the oxygen lance height is adjusted.

[0045] In some embodiments, the first amount is 980-1200 kg.

[0046] In the embodiments of the present application, before long-term shutdown or resuming production after the end of routine maintenance, it is usually necessary to perform the oven operation. When performing the oven operation, the amount of coke addition batch is reasonably allocated, and 980-1200 kg of coke is added first before ignition, and the remaining coke is added during the oven operation to avoid insufficient combustion of coke due to too large concentrated addition amount. Specifically, 980 kg, 1000 kg, 1200 kg, etc. of coke is added to the converter after shutdown before ignition.

[0047] In the embodiments of the present application, the oven operation process is divided into two stages, the first stage is to mix the coke in the furnace by using the large-angle swing oven method after the oven operation to relieve the degree of coke accumulation, and secondly, the coke addition criteria during the oven operation process is formulated, and the coke is added in small amounts and multiple times, and the oxygen lance height is adjusted in time after the coke is added to mix the coke and improve the coke combustion efficiency.

[0048] In some embodiments, the time of the first oven operation is 15-25 min.

[0049] In some embodiments, the swing oven operation includes: swinging the oven backward to-60°, and then swinging the oven forward to 90° to perform the swing oven operation.

[0050] In some embodiments, the number of swing oven operations is 2-3 times.

[0051] In the embodiments of the present application, the oven is paused after 15-25 min of starting the oven, at this time the oxygen lance is withdrawn from the furnace opening, and the oven is swung backward to-60°, and then swung forward to 90°, the swing oven operation can be 2 or 3 times, and the swing oven range is based on the coke not flowing out of the furnace opening; the large-angle swing oven can further mix the coke in the furnace to make the coke fully burn. Specifically, the time of the first oven operation can be 15 min, 20 min, 25 min, etc.

[0052] In some embodiments, the second oven operation is performed on the converter after the swing oven operation, and the remaining coke is added in batches, including:

[0053] The second oven operation is performed on the converter after the swing oven operation, and 150-250 kg of coke is added at the start of the second oven operation,

[0054] and 150-250 kg of coke is added every 8 min during the second oven operation.

[0055] In the embodiment of the present application, after the large-angle swing furnace, the second time of baking the furnace is carried out, and immediately after the start of the second time of baking the furnace, an appropriate amount of coke is added, and then every 8 minutes during the baking process, an appropriate amount of coke is added once; the CO2 generation amount in the coke combustion process is detected by using the converter flue gas analyzer to evaluate the degree of coke combustion, and after adding 150-250 kg of coke, the CO2 generation amount starts to rise, and the data statistics show that after 8 minutes of combustion, the CO2 generation amount starts to decrease significantly, at this time, it can be considered that the combustion capacity of the added coke is insufficient, and new coke needs to be supplemented. Specifically, in the second baking operation, the amount of the coke can be 150 kg, 200 kg, 250 kg, etc.

[0056] In some embodiments, the adjusting the oxygen lance height after adding each batch of the remaining coke comprises: adjusting the oxygen lance height according to H-(H-200)-H after adding each batch of the remaining coke; wherein H represents the initial height of the oxygen lance.

[0057] In the embodiment of the present application, during the second baking operation, immediately after adding each batch of the remaining coke, the oxygen lance height is lowered by 200 mm, and after the oxygen lance is lowered to the specified position, it is immediately restored to the initial height. By lowering the oxygen lance, the coke can be further impacted and dispersed by the enhanced effect of the oxygen jet while adding the coke, which can avoid the accumulation of coke and improve the combustion efficiency of the coke.

[0058] In some embodiments, the oxygen flow rate is 12000 m 3 / h-14000 m 3 / h.

[0059] In the embodiment of the present application, a reasonable oxygen flow rate is controlled, and the oxygen flow rate during the entire baking process is set to be between 12000 m 3 / h and 14000 m 3 / h. If the oxygen flow rate is too low, the oxygen jet will only impact the surface of the coke, and the coke accumulated inside cannot be efficiently burned. If the oxygen flow rate is too high, the oxygen jet will disperse the coke too much, and even the coke will be bounced and splashed out of the converter port. The optimal oxygen flow rate can be determined by observing the state of the coke splashing at the port. For a 210-ton converter, when the oxygen flow rate is too high, coke splashing is prone to occur. Specifically, the oxygen flow rate can be 12000 m 3 / h, 13000 m 3 / h, 14000 m 3 / h, etc.

[0060] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not used to limit the scope of the present application. The experimental methods in the following examples, if no specific conditions are noted, are generally determined according to national standards. If there is no corresponding national standard, the general international standards, conventional conditions, or the conditions suggested by the manufacturer are used.

[0061] The embodiments of the present application provide a furnace heating method, which comprises:

[0062] S11, performing slag splashing protection operation on three consecutive heats before the planned shutdown of the converter, and then performing shutdown;

[0063] S21, performing furnace heating operation on the converter after shutdown, and controlling the oxygen flow rate in the furnace heating operation; wherein the furnace heating operation comprises:

[0064] adding coke with a first addition amount into the converter before ignition after shutdown;

[0065] performing first furnace heating operation on the converter with the first addition amount of coke, and controlling the time of the first furnace heating operation, and then performing furnace shaking operation;

[0066] performing second furnace heating operation on the converter after the furnace shaking operation, and adding the remaining coke in batches; wherein the oxygen lance height is adjusted after adding each batch of the remaining coke. For specific process implementation, please refer to the following examples 1-3.

[0067] Example 1

[0068] 1, 210 tons of converter, planned to be shutdown for example repair after smelting 232508999 heats, example repair for 18 hours, and furnace heating operation is needed before resuming production after example repair;

[0069] 2, starting to control slag splashing protection operation for three heats before shutdown, 232508997 heat for 2.1 min, 232508998 heat for 1.5 min, 232528999 heat without slag splashing protection, 232508999 heat for 2 min after slagging with the furnace mouth downward, and the residual slag in the furnace is completely discharged;

[0070] 3, starting furnace heating after example repair, adding 1012 kg of coke before ignition, and the oxygen flow rate used for furnace heating is 14000 m 3 / h;

[0071] 4. After 20 minutes of baking, the baking was paused, the converter was shaken in a large angle for three times, and the coke in the furnace was mixed well. After the large angle shaking, the baking was continued. First, 201 kg of coke was added, then 200 kg of coke was added every 8 minutes. The oxygen lance height was reduced from 1100 mm to 990 mm each time, and then immediately restored to 1100 mm. A total of 1246 kg of coke was added in the second baking process, which was divided into 6 times.

[0072] Results: No coke sticking to the bottom of the furnace occurred at the end of the baking.

[0073] Example 2

[0074] 1. A 210-ton converter, scheduled to be stopped for maintenance after smelting 232403536 heats, the maintenance lasted for 24 hours. Before resuming production after the maintenance, the baking operation was needed.

[0075] 2. The three heats before stopping were controlled for slag splashing and furnace protection. The slag splashing time of 232403534 was 2.3 minutes, the slag splashing time of 232403535 was 1.1 minutes, and the slag splashing of 232403536 was not performed. After the slag of 232403536 was poured, the furnace mouth was kept downward for 1.8 minutes, and the residual slag in the furnace was poured out.

[0076] 3. After the maintenance was completed, the baking was started. Before ignition, 1033 kg of coke was added. The oxygen flow rate used in the baking was 13000 m 3 / h;

[0077] 4. After 20 minutes of baking, the baking was paused, the converter was shaken in a large angle for three times, and the coke in the furnace was mixed well. After the large angle shaking, the baking was continued. First, 208 kg of coke was added, then 200 kg of coke was added every 8 minutes. The oxygen lance height was reduced from 1200 mm to 1000 mm each time, and then immediately restored to 1200 mm. A total of 1088 kg of coke was added in the second baking process, which was divided into 5 times.

[0078] Results: No coke sticking to the bottom of the furnace occurred at the end of the baking.

[0079] Example 3

[0080] 1. A 210-ton converter, scheduled to be stopped for maintenance after smelting 232404882 heats, the maintenance lasted for 18 hours. Before resuming production after the maintenance, the baking operation was needed.

[0081] 2. The three heats before stopping were controlled for slag splashing and furnace protection. The slag splashing time of 232404880 was 2.1 minutes, the slag splashing time of 232404881 was 1.3 minutes, and the slag splashing of 232404882 was not performed. After the slag of 232404882 was poured, the furnace mouth was kept downward for 2 minutes, and the residual slag in the furnace was poured out.

[0082] 3. After the end of the example repair, start the oven, add 1022 kg of coke before ignition, and the oxygen flow used for the oven is 13000 m 3 / h;

[0083] 4. After the oven is heated for 20 min, the oven is paused, and the converter is shaken at a large angle three times in front and back, and the coke in the furnace is well mixed. After the large-angle shaking is completed, the oven is continued, 212 kg of coke is first added, and then 200 kg of coke is added every 8 min, the oxygen lance height is reduced from 1150 mm to 950 mm each time, and then immediately restored to 1150 mm, a total of 1033 kg of coke is added in two oven processes, and the coke is added in five times;

[0084] Results: No coke sticking to the bottom of the oven occurred at the end of the oven.

[0085] Comparative Example 1

[0086] 1. The 210-ton converter was scheduled to be smelted for 232401332 heats and then stopped for repair, the example repair was 24 hours, and the oven operation needed to be performed before the production was resumed after the example repair;

[0087] 2. The three heats before stopping did not control the slag splashing and furnace protection operation, and the conventional process was used for slag splashing and furnace protection, the slag splashing time of 232401330 heat was 4.5 min, the slag splashing time of 232401331 heat was 4.8 min, the slag splashing time of 232401332 heat was 5.5 min, and the converter was shaken straight immediately after the slag of 232401332 heat was poured, and a small amount of residual slag was left in the furnace;

[0088] 3. After the end of the example repair, start the oven, add 1532 kg of coke before ignition, and the oxygen flow used for the oven is 13000 m 3 / h;

[0089] 4. The oven is continuously heated, 489 kg of coke is added after the oven is heated for 20 min, and then 500 kg of coke is added every 15 min, the oxygen lance height is controlled at 1200 mm, a total of 4 batches of coke are added, the oxygen lance is not moved during the whole oven process, a total of 3512 kg of coke is added, and the total oven time is 80 min;

[0090] Results: A large amount of coke adheres to the bottom of the converter at the end of the oven, and the first to third heats of the smelted steel after the oven are ended, due to the coke on the bottom of the furnace, the carbon content of the molten steel is high, and the quality of the molten steel is affected.

[0091] Through the analysis of the above examples 1-3 and comparative example 1, it can be seen that the oven method provided in the examples realizes the purpose of no coke sticking to the bottom of the oven at the end of the oven, thereby facilitating the smelting of the molten steel in the later period and ensuring the quality of the molten steel.

[0092] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A method for drying an oven, characterized in that, The method includes: Slag splashing and furnace protection operations were carried out for the three consecutive heats before the planned shutdown of the converter, and then the converter was shut down. The converter is subjected to a drying operation after shutdown, and the oxygen flow rate is controlled during the drying operation; wherein, the drying operation includes: Before ignition, coke with a first addition amount is added to the converter after it has been shut down; The converter with a first amount of coke is subjected to a first oven drying operation, and the time of the first oven drying operation is controlled, followed by a furnace shaking operation. The converter is subjected to a second drying operation after the shaking operation, and the remaining coke is added in batches; wherein, after each batch of the remaining coke is added, the oxygen lance height is adjusted. The slag splashing operation for the three consecutive heats prior to the planned converter shutdown includes: The slag splashing protection time for the third furnace before shutdown is <3 minutes, and the slag splashing protection time for the second furnace before shutdown is <2 minutes. The slag splashing protection time for the first furnace before shutdown is 0 minutes; The slag splashing operation for the three consecutive heats prior to the planned converter shutdown includes: For the three consecutive heats before the planned shutdown of the converter, slag splashing and furnace protection operations shall be carried out; among them, when the slag is poured out in the first heat before shutdown, the furnace opening shall be kept facing downward for more than 1 minute after the slag is poured out. The first addition amount is 980-1200 kg; The first oven operation time is 15-25 minutes; The process of performing a second drying operation on the converter after the shaking operation, and adding the remaining coke in batches, includes: After the initial shaking operation, the converter undergoes a second drying operation, with 150-250 kg of coke added at the start of this operation. And during the operation of the second oven, 150-250 kg of coke is added every 8 minutes; The step of adjusting the oxygen lance height after adding each batch of remaining coke includes: After adding each batch of the remaining coke, the oxygen lance height is adjusted according to H-(H-200)-H; where H represents the initial oxygen lance height.

2. The method according to claim 1, characterized in that, The oxygen flow rate is 12000m 3 / h-14000m 3 / h。 3. The method according to claim 1, characterized in that, The furnace shaking operation includes: The furnace is rocked backward to -60°, and then forward to 90° to perform the furnace rocking operation.

4. The method according to claim 1 or 3, characterized in that, The shaking operation is performed 2-3 times.

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