Coke load regulation and control method

Abstract

The invention discloses a coke load regulation and control method, and belongs to the technical field of blast furnace smelting. The method comprises the following steps: firstly, obtaining the strength and coke ratio of a comprehensive stock column skeleton during the smooth running period of the blast furnace condition as reference values; and calculating the strength of the comprehensive stock column framework according to the proportion structure of the coke which is blended in real time and the post-reaction strength of each single coke, comparing the strength with the strength standard of the stock column framework, and calculating to obtain the coke load which needs to be adjusted, so that the stability of the comprehensive stock column framework in the blast furnace is realized. According to the method, the blast furnace is adjusted by taking an innovative method of'stock column framework strength in-furnace uniformity 'as a central idea, the influence of material column framework fluctuation on smooth operation of the blast furnace is eliminated, a comprehensive stock column framework reference value of furnace condition smooth operation is returned in time, and uniformity and stability of stock columns are realized, so that smooth operation of the furnace condition is realized, stability of airflow in the furnace is realized, and cost and consumption are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace smelting, and in particular to a coke load regulation method. Background Art

[0002] The core requirement of blast furnace smelting is long-term stable furnace condition. The smooth furnace condition is an important guarantee to meet the requirements of "low consumption, long life, safety and environmental protection". Coke is an important raw material for blast furnace ironmaking. In the process of blast furnace smelting, it plays the role of reducing agent, carburizing agent, heat provider and material column skeleton. The role of material column skeleton is very important for blast furnace smelting. In the high temperature area of ​​blast furnace, after the iron ore softens and melts, coke is the only material in the blast furnace that exists in solid state. It is the skeleton supporting the material column and the permeable passage for the coal gas generated in front of the tuyere to flow from bottom to top. Low coke strength will cause operational problems such as reduced permeability of the furnace body and furnace, disordered airflow and temperature distribution, and suspended materials, which will seriously affect the smooth operation of the blast furnace. Therefore, coke must have sufficient strength.

[0003] Specifically in the smelting step, in order to ensure the smooth operation of the blast furnace, it is necessary to rely on coke of sufficient strength to maintain sufficient material column skeleton strength, and its important technical indicator is coke load, that is, the ratio of ore batch to compensating coke batch. For the sake of energy saving, consumption reduction, cost reduction and efficiency improvement, smelting plants do not purchase the same type of coke on a fixed basis, but frequently choose a combination of multiple varieties and different qualities of coke for use. As a result, the coke charge structure is complex, which is more likely to cause the material column skeleton strength to loosen or even collapse, resulting in fluctuations in furnace conditions. Traditionally, smelters use experience to fine-tune the coke load, which is not only subjective and arbitrary, but also because the coke raw materials change, the past successful experience is no longer applicable. Therefore, it is impossible to achieve it in one step; and because it cannot be adjusted in one go, during the adjustment process, insufficient coke addition will cause the material column to collapse due to insufficient skeleton strength, and excessive coke addition will affect costs and lead to losses. However, due to the continuity of smelting, it is impossible to obtain the status of the furnace in real time through the change of molten iron quality or air flow pressure difference. The specific results of each adjustment need to wait until the end of a furnace to find out, which takes about 8 hours for a shift. Multiple adjustments will affect multiple furnaces of molten iron, which takes multiple shifts, and requires additional shutdowns for maintenance and refractory material replacement, which is costly. Therefore, exploring data calculations to change the traditional method of using experience to make judgments, reasonably control the coke load, and obtain stable coke column skeleton strength is the key to ensuring smooth furnace conditions. Summary of the invention

[0004] In view of the above-mentioned prior art, the purpose of the present invention is to provide a coke load control method. The present invention aims to compensate the coke ratio by utilizing the influence of the fluctuation of the material column skeleton, eliminate the influence of the fluctuation of the material column skeleton on the smooth operation of the blast furnace, and timely return to the comprehensive material column skeleton reference value of the smooth operation of the furnace condition, so as to achieve uniform and stable material column, thereby achieving the purpose of smooth operation of the furnace condition.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A first aspect of the present invention provides a coke load control method, comprising the following steps:

[0007] (1) Determine the material column skeleton strength and coke ratio during the forward furnace condition, which are used as the material column skeleton strength benchmark and coke ratio benchmark, denoted as F 1 and K 1 ;

[0008] (2) Determine the coke ratio scheme for blast furnace use and obtain the post-reaction strength of the coke used; the weight ratio of each coke to all the cokes to be used is recorded as AZ, and the corresponding post-reaction strength of the coke is recorded as a%-z%;

[0009] (3) According to the coke ratio scheme in step (2), the comprehensive strength after reaction is calculated as the material column skeleton strength, denoted as F, and the calculation formula is as follows:

[0010] F=(A×a%)+(B×b%)+(C×c%)+···+(Z×z%);

[0011] (4) The material column skeleton strength benchmark F 1 Subtract the strength F of the material column skeleton and record it as F 2 ; This is used to indicate the fluctuation of the strength of the material column skeleton, which is used as the basis for compensating the coke ratio; the compensation coke ratio is calculated based on the fact that the coke ratio is affected by 5kg / t due to the 1% fluctuation of the material column skeleton strength, and is recorded as K 2 ; The calculation formula for the compensation focal ratio is as follows:

[0012] K 2 =F 2 ×5+K 1 =(F 1 -F)×5+K 1 ;

[0013] (5) According to the compensation focal ratio K 2 Calculate the compensation coke batch, denoted as O 1 ; The calculation formula for compensating coke batch is:

[0014] O 1 =(K 2 × metal production)÷number of batches of material cut÷1000;

[0015] (6) Add the ore batch and the compensation coke batch according to the setting 1 The ratio of is used to calculate the coke load that needs to be adjusted. The calculation formula is as follows:

[0016] Coke load to be adjusted = blast furnace ore batch ÷ compensation coke batch O 1 ;

[0017] (7) The value of the coke load to be adjusted is used as a parameter to regulate the coke load of the blast furnace and obtain a material column skeleton with sufficient strength.

[0018] Furthermore, in step (2), a coke sample is obtained according to the method specified in GB / T 1997-2008 "Collection and Preparation of Coke Samples"; and a coke sample is taken according to the method specified in GB / T 4000-2017 "Test Method for Reactivity and Post-Reaction Strength of Coke" to detect the post-reaction strength of coke.

[0019] Furthermore, in step (2), the diameter of the coke sample taken is not less than 25 mm.

[0020] Furthermore, in step (2), 50-70 kg of each type of coke is taken.

[0021] Furthermore, in step (5), the metal is a ferrous metal or a non-ferrous metal.

[0022] The second aspect of the present invention provides application of the coke load control method in smelting.

[0023] Furthermore, the smelting is blast furnace smelting.

[0024] Furthermore, the products of smelting are ferrous metals or non-ferrous metals.

[0025] Beneficial effects of the present invention:

[0026] The present invention adjusts the blast furnace with the innovative method of "uniformity of material column skeleton strength in the furnace" as the central idea, and timely returns and compensates for changes in the material column skeleton, and reversely calculates the coke load to adjust the strength of the blast furnace supporting material column, so as to achieve uniformity of the material column in the furnace, make up for the fluctuation problem of the material column skeleton, and achieve the purpose of stabilizing the airflow in the furnace and saving costs and reducing consumption. The control steps of the present invention are as follows: first, the comprehensive material column skeleton strength and coke ratio during the period of smooth operation of the blast furnace are obtained as the reference value, that is, the material column skeleton strength reference and the coke ratio reference; according to the coke ratio structure added in real time, the comprehensive material column skeleton strength is calculated according to the post-reaction strength of each single type of coke, and it is compared with the material column skeleton strength reference, and the compensation coke amount, the affected coke ratio and the compensated coke batch are calculated according to the coke ratio increase or decrease of 5kg / t for every decrease of ±1%, and the ratio of the ore batch to the compensated coke batch is the coke load that needs to be adjusted, thereby achieving the stability of the comprehensive material column skeleton in the blast furnace and achieving smooth operation of the blast furnace. DETAILED DESCRIPTION

[0027] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0028] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0029] The test materials used in the examples of the present invention without specific description are all conventional test materials in the field and can be purchased through commercial channels. The self-produced dry quenched coke and self-produced water quenched coke used in the present invention are produced by the company; Xingyujia and Yezun coke are purchased from Xingyujia Trading Company and Yezun Trading Company respectively.

[0030] The way to ensure the smooth running of the blast furnace is to maintain the stability of the strength of the material column skeleton through coke of sufficient strength. The most direct way to obtain coke of sufficient strength is for smelting enterprises to obtain high-quality coal and independently produce high-quality coke for blast furnace smelting. However, except for a very small number of industry leaders that have a full industrial chain from coal mining to smelting, the above plan is not realistic for most of the remaining more than 6,000 ferrous metal smelting-related companies. Based on environmental protection and energy conservation and consumption reduction, for a few smelting companies that are willing to supply coke on their own, there is a quota for coke production capacity, and they cannot supply enough coke themselves, nor can they start new production capacity; or even if they have production capacity, they may give up independent production because of non-compliance with environmental protection standards; therefore, they can only choose to buy finished coke on the market. When companies purchase coke, based on price, season, transportation capacity, and adjustments to the supply and demand of their own raw materials, they often choose to purchase products from multiple coke suppliers for smelting. For coke production enterprises located in the upstream of the industry, since the raw material of coke is coal, coke production enterprises also face the problem of raw material supply similar to that of downstream smelting enterprises, that is, they cannot continuously obtain a single and sufficient supply of coal raw materials, and can only obtain coal from multiple channels in the market. As a result, as the physical and chemical properties of the coal raw materials themselves change, the quality of coke products will also fluctuate, and this situation of coal blending and coking will exist for a long time. Therefore, the different physical and chemical composition of coal affects the quality of coke, and the change of the physical and chemical composition of coke affects the state of the furnace. For smelting enterprises, this is a technical problem that needs to be faced every day in production.

[0031] Example 1: Coke load control when using two mixed cokes

[0032] The experimental verification site of the present invention is a blast furnace of the ironmaking department of a steel group in Shandong, and the coke used is two types: industrial coke and self-produced water-quenched coke.

[0033] (1) According to the status data of the blast furnace during the previous period of operation, the benchmark values ​​were statistically analyzed. The material column skeleton strength was determined to be 67.6% and the coke ratio was 346kg / t, which were used as the benchmark values, namely the material column skeleton strength benchmark F 1 The base focal ratio is 67.6%. 1 It is 346kg / t.

[0034] (2) The proportion of blast furnace changes (the mass ratio of each coke in the mixed coke used in subsequent production) is as follows in Table 1:

[0035] Table 1 Blast furnace change ratio

[0036] Coke Type Industry Zun Jiao Self-produced water quenching Ratio 20％ 80％

[0037] (3) Test in accordance with the method specified in GB / T 1997-2008 “Collection and Preparation of Coke Samples” to obtain coke samples. Take coke no smaller than 25 mm, including 60.0 kg of industrial coke and 60.0 kg of self-produced water-quenched coke.

[0038] (4) According to GB / T 4000-2017 "Test Method for Reactivity and Post-Reaction Strength of Coke", the post-reaction strength of various cokes was tested respectively. The test results are shown in Table 2 below:

[0039] Table 2 Post-reaction strength of coke

[0040] Coke Type Industry Zun Jiao Self-produced water quenching Post-reaction strength 65.5％ 61.5％

[0041] (5) Calculate the comprehensive strength after reaction according to the coke ratio, as the material column skeleton strength, denoted as F. F is the sum of the added ratio of coke used and the strength after reaction of coke. The calculation results are as follows;

[0042] F=(20%×65.5)+(80%×61.5)=62.3%

[0043] (6) Material column skeleton strength standard F 1 The difference between F and 2 , as the basis for compensating coke. According to ironmaking theory, the compensating coke is calculated based on the coke ratio of 5kg / t affected by a 1% fluctuation in the strength of the material column, and is recorded as K 2 , unit is kg / t. The calculation formula of compensation coke ratio is as follows:

[0044] K 2 =F 2 ×5+K 1 =(F 1 -F)×5+K 1

[0045] The calculation results are as follows;

[0046] K 2 =(67.6-62.3)×5+346=372.5

[0047] (7) According to the compensation focal ratio K 2 Calculate the compensation coke batch, denoted as O 1 , the unit is t; according to the iron production (shift production) set for each shift of the factory, 1600t, the set number of unloading batches is 48 batches, and the production compensation coke batch is O 1 The calculation formula is as follows:

[0048] O 1 = Compensation focal ratio K 2 × shift production ÷ number of batches ÷ 1000

[0049] The calculation results are as follows;

[0050] O 1 =372.5×1600÷48÷1000=12.42

[0051] (8) The coke load to be adjusted is the ore batch and the compensation coke batch. 1 The ratio is used to adjust the coke load of the blast furnace. The factory sets the blast furnace ore batch to 54t, and the formula for adjusting the coke load is as follows:

[0052] Coke load to be adjusted = blast furnace ore batch ÷ output compensation coke batch O 1

[0053] The calculation results are as follows;

[0054] Coke load to be adjusted = 54 ÷ 12.42 = 4.35

[0055] (9) Numerical revision of the coke load of the blast furnace adjustment to 4.4 control.

[0056] Example 2: Coke load control when using three kinds of mixed coke

[0057] The experimental verification site of the present invention is a blast furnace of the ironmaking department of a steel group in Shandong. The coke used is three types: self-produced dry quenching coke, Xingyujia and self-produced water quenching coke.

[0058] (1) According to the status data of the blast furnace during the previous period of operation, the benchmark values ​​were statistically analyzed. The material column skeleton strength was determined to be 67.6% and the coke ratio was 346kg / t, which were used as the benchmark values, namely the material column skeleton strength benchmark F 1 The base focal ratio is 67.6%. 1 It is 346kg / t.

[0059] (2) The proportion of blast furnace changes (the mass ratio of each coke in the mixed coke used in subsequent production) is as follows in Table 3:

[0060] Table 3 Blast furnace change ratio

[0061] Coke Type Self-produced CDQ Xing Yujia Self-produced water quenching Ratio 35％ 25％ 40％

[0062] (3) Test in accordance with the method specified in GB / T 1997-2008 "Collection and Preparation of Coke Samples" to obtain coke samples. Take coke no smaller than 25 mm, including 60.0 kg of self-produced dry quenched coke, 60.0 kg of Xingyujia coke, and 60.0 kg of self-produced water-quenched coke.

[0063] (4) According to GB / T 4000-2017 "Test Method for Reactivity and Post-Reaction Strength of Coke", the post-reaction strength of various cokes was tested respectively. The test results are shown in Table 4 below:

[0064] Table 4 Post-reaction strength of coke

[0065] Coke Type Self-produced CDQ Xing Yujia Self-produced water quenching Post-reaction strength 68.5％ 65.0％ 59.0％

[0066] (5) Calculate the comprehensive strength after reaction according to the coke ratio, as the material column skeleton strength, denoted as F. F is the sum of the added ratio of coke used and the strength after reaction of coke. The calculation results are as follows;

[0067] F=(35%×68.5)+(25%×65)+(40%×59)=64.7%

[0068] (6) Material column skeleton strength standard F 1 The difference between F and 2 , as the basis for compensating coke. According to ironmaking theory, the compensating coke is calculated based on the coke ratio of 5kg / t affected by a 1% fluctuation in the strength of the material column, and is recorded as K 2 , unit is kg / t. The calculation formula of compensation coke ratio is as follows:

[0069] K 2 =F 2 ×5+K 1 =(F 1 -F)×5+K 1

[0070] The calculation results are as follows;

[0071] K 2 =(67.6-64.7)×5+346=360.5

[0072] (7) According to the compensation focal ratio K 2 Calculate the compensation coke batch, denoted as O 1 , the unit is t; according to the iron production (shift production) set for each shift of the factory, 1600t, the set number of unloading batches is 48 batches, and the production compensation coke batch is O 1 The calculation formula is as follows:

[0073] O 1 = Compensation focal ratio K 2 × shift production ÷ number of batches ÷ 1000

[0074] The calculation results are as follows;

[0075] O 1 =360.5×1600÷48÷1000=12.02

[0076] (8) The coke load to be adjusted is the ore batch and the compensation coke batch. 1 The ratio is used to adjust the coke load of the blast furnace. The factory sets the blast furnace ore batch to 54t, and the formula for adjusting the coke load is as follows:

[0077] Coke load to be adjusted = blast furnace ore batch ÷ output compensation coke batch O 1

[0078] The calculation results are as follows;

[0079] Coke load to be adjusted = 54t ÷ 12.02 = 4.49

[0080] (9) The numerical value is revised to 4.5 for the coke load adjustment of the blast furnace.

[0081] Comparative Example 1 Coke load control during the previous blast furnace operation

[0082] According to the status data of the blast furnace during the previous period of operation, the material column skeleton strength is 67.6% and the coke ratio is 346kg / t. 2 Calculate the compensation coke batch, denoted as O 1 , the unit is t; according to the iron production (shift production) set for each shift of the factory, 1600t, the set number of unloading batches is 48 batches, and the production compensation coke batch is O 1 The calculation formula is as follows:

[0083] O 1 = Compensation focal ratio K 2 × shift production ÷ number of batches ÷ 1000

[0084] The calculation results are as follows;

[0085] O 1 =346×1600÷48÷1000=11.53

[0086] The coke load to be adjusted is the ore batch and the compensation coke batch O 1 The ratio is used to adjust the coke load of the blast furnace. The factory sets the blast furnace ore batch to 54t, and the formula for adjusting the coke load is as follows:

[0087] Coke load to be adjusted = blast furnace ore batch ÷ output compensation coke batch O1

[0088] The calculation results are as follows;

[0089] Coke load to be adjusted = 54 ÷ 11.53 = 4.68

[0090] The numerical value is revised to 4.7 control of coke load adjusted for blast furnace.

[0091] Comparison of the data of Example 1-Example 2 and Example 1: If the coke load of 4.7 in Example 1 is adjusted to the coke load of 4.4 in Example 1, with 0.1 as an adjustment unit, it takes 3 adjustments to reach a reasonable value and maintain the furnace condition; if the coke load of 4.7 in Example 1 is adjusted to the coke load of 4.5 in Example 2, with 0.1 as an adjustment unit, it takes 2 adjustments to reach a reasonable value and maintain the furnace condition; therefore, the adjustment process needs to go through at least 2 shifts of working time (16h), waste 2 furnaces, and produce 4800t of unqualified steel products. The method of calculation using the formula of this embodiment can avoid the above situation, achieve energy saving and consumption reduction, and ensure the furnace condition is smooth.

[0092] The present invention adjusts the blast furnace with "uniformity of material column skeleton strength in the furnace" as the central idea. After the material column skeleton changes, it returns and compensates in time, and reversely calculates the coke load to adjust the strength of the blast furnace supporting material column, so as to achieve uniformity of the material column in the furnace, compensate for the fluctuation problem of the material column skeleton, and realize stable airflow in the furnace and cost saving and consumption reduction.

[0093] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A coke load control method, characterized in that: The following steps are involved: (1) Determine the material column skeleton strength and coke ratio during the forward operation of the furnace condition, which are used as the material column skeleton strength benchmark and coke ratio benchmark, and are recorded as F1 and K1; (2) Determine the coke ratio scheme for blast furnace use and obtain the post-reaction strength of the coke used; the weight ratio of each coke to all the cokes to be used is recorded as AZ, and the corresponding post-reaction strength of the coke is recorded as a%-z%; (3) According to the coke ratio scheme in step (2), the comprehensive strength after reaction is calculated as the material column skeleton strength, denoted as F, and the calculation formula is as follows: F=(A×a%)+(B×b%)+(C×c%)+···+(Z×z%); (4) Subtract the material column skeleton strength reference F1 from the material column skeleton strength F, and record it as F2; ​​this represents the fluctuation of the material column skeleton strength, which serves as the basis for compensating the coke ratio; the compensating coke ratio is calculated based on the fact that the coke ratio is affected by 5kg / t due to the fluctuation of the material column skeleton strength by 1%, and is recorded as K2; the formula for calculating the compensating coke ratio is as follows: K2=F2×5+K1=(F1-F)×5+K1; (5) Calculate the compensation coke batch according to the compensation coke ratio K2, denoted as O1; the calculation formula for the compensation coke batch is: O1 = (K2 × metal output) ÷ number of batches ÷ 1000; (6) According to the ratio of the set added ore batch to the compensation coke batch O1, the coke load to be adjusted is calculated and the calculation formula is as follows: Coke load to be adjusted = blast furnace ore batch ÷ compensation coke batch O1; (7) The value of the coke load to be adjusted is used as a parameter to regulate the coke load of the blast furnace and obtain a material column skeleton with sufficient strength.

2. The coke load control method according to claim 1, characterized in that: In step (2), a coke sample is obtained according to the method specified in GB / T1997-2008 "Collection and preparation of coke samples"; and a coke sample is taken according to the method specified in GB / T 4000-2017 "Test method for reactivity and post-reaction strength of coke" to detect the post-reaction strength of coke.

3. The coke load control method according to claim 2, characterized in that: In step (2), the diameter of the coke sample taken is not less than 25 mm.

4. The coke load control method according to claim 2, characterized in that: In step (2), 50-70 kg of each type of coke is taken.

5. The coke load control method according to claim 1, characterized in that: In step (5), the metal is a ferrous metal or a non-ferrous metal.

6. Application of the coke load control method according to any one of claims 1 to 5 in smelting.

7. The use according to claim 6, characterized in that: The smelting is blast furnace smelting.

8. The use according to claim 6, characterized in that: The products of smelting are ferrous metals or non-ferrous metals.