CN117875992A - Method for determining addition amount of steel scraps of torpedo ladle - Google Patents
Method for determining addition amount of steel scraps of torpedo ladle Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 222
- 239000010959 steel Substances 0.000 title claims abstract description 222
- 238000000034 method Methods 0.000 title claims abstract description 33
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 208
- 229910052742 iron Inorganic materials 0.000 claims abstract description 104
- 238000009628 steelmaking Methods 0.000 claims abstract description 40
- 230000008901 benefit Effects 0.000 claims abstract description 36
- 238000011084 recovery Methods 0.000 claims abstract description 28
- 239000002893 slag Substances 0.000 claims description 25
- 238000005098 hot rolling Methods 0.000 claims description 21
- 229910052799 carbon Inorganic materials 0.000 claims description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 18
- 238000009749 continuous casting Methods 0.000 claims description 16
- 239000002699 waste material Substances 0.000 claims description 13
- 239000003795 chemical substances by application Substances 0.000 claims description 10
- 238000002844 melting Methods 0.000 claims description 10
- 230000008018 melting Effects 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 238000005096 rolling process Methods 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 7
- 239000007769 metal material Substances 0.000 claims description 7
- 230000008569 process Effects 0.000 claims description 7
- 230000000630 rising effect Effects 0.000 claims description 7
- 229910000805 Pig iron Inorganic materials 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 230000004927 fusion Effects 0.000 claims description 6
- 239000007789 gas Substances 0.000 claims description 6
- 239000002910 solid waste Substances 0.000 claims description 6
- 238000006477 desulfuration reaction Methods 0.000 claims description 5
- 230000023556 desulfurization Effects 0.000 claims description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 230000003647 oxidation Effects 0.000 claims description 4
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- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 claims description 3
- 239000000571 coke Substances 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- 230000001502 supplementing effect Effects 0.000 claims 1
- 230000000694 effects Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 239000002918 waste heat Substances 0.000 description 4
- 238000003723 Smelting Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
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- RMCCONIRBZIDTH-UHFFFAOYSA-N 2-(2-methylprop-2-enoyloxy)ethyl 1,3-dioxo-2-benzofuran-5-carboxylate Chemical compound CC(=C)C(=O)OCCOC(=O)C1=CC=C2C(=O)OC(=O)C2=C1 RMCCONIRBZIDTH-UHFFFAOYSA-N 0.000 description 1
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- 238000009851 ferrous metallurgy Methods 0.000 description 1
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Abstract
The invention discloses a method for determining the addition amount of steel scraps of a torpedo tank, which mainly solves the technical problems that the benefit of the torpedo tank for adding steel scraps cannot be evaluated and the optimal addition amount of steel scraps cannot be determined under the existing conditions. The technical scheme is that the method for determining the addition amount of the steel scraps of the torpedo tank comprises the following steps: 1) Calculating the temperature loss of molten iron saved by adding scrap steel into the torpedo ladle; 2) Calculating the steelmaking cost increment of the torpedo ladle and the scrap steel; 3) Calculating the heat recovery benefit of the torpedo tank; 4) Calculating the benefit of adding scrap steel into the torpedo ladle; 5) And determining the addition amount of the steel scraps of the torpedo ladle. The method can determine the addition amount of the steel scraps of the torpedo tank according to market changes, thereby realizing the maximization of benefits.
Description
Technical Field
The invention relates to a steel scrap consumption decision technology, in particular to a method for determining the steel scrap addition of a torpedo ladle, and belongs to the technical field of ferrous metallurgy.
Background
The carbon emission of recycling scrap steel is far smaller than that of producing molten iron by a blast furnace, so that the improvement of scrap steel ratio and the reduction of unit consumption of molten iron in the steelmaking production process are important paths for realizing double carbon. After the steel is added into the torpedo tank, the residual heat in the torpedo tank can be utilized to preheat the steel scraps, so that the heat radiation loss of the empty torpedo tank through a tank opening is greatly reduced. Although the heat loss can be reduced after the scrap steel is added into the torpedo tank, the temperature drop of molten iron in the torpedo tank can be increased along with the increase of the addition amount of the scrap steel, the properties of molten iron slag are changed, and the adverse effect on steelmaking production is caused. In order to reduce the temperature drop of molten iron, the waste steel is preheated and then added into the torpedo tank, so that the consumption of the waste steel is increased. The steel scrap adding amount in the torpedo tank is not as high as possible, the benefit of the torpedo tank for adding the steel scrap is calculated according to the conditions of steel scrap price, hot rolled coil price and the like, the steel scrap adding amount of the torpedo tank is dynamically adjusted, and the profit maximization is realized.
The Chinese patent application document of application publication No. CN110205419A discloses a method and a system for calculating the cost saving of the blast furnace added scrap smelting, fully considers the influence of scrap components on the scrap smelting process and carburization amount, scientifically and reasonably calculates the cost saving of the blast furnace added scrap smelting by combining the factors of coke price, scrap price, hearth molten iron component, tapping temperature, molten iron price, molten iron increment and the like, and guides a blast furnace operator to select economic scrap raw materials; however, this technology is directed to the case of adding scrap to a blast furnace, and the effect of adding scrap to a torpedo tank and the effect of the return are completely different from those.
The Chinese patent application document of application publication No. CN113462843A discloses a method for adding scrap steel into a torpedo ladle, firstly, adding scrap steel into an empty torpedo ladle, then adding molten iron into the torpedo ladle, and adding iron into a ladle after the torpedo ladle reaches steelmaking, wherein the adding amount of the scrap steel of the torpedo ladle is adjusted according to the slag condition of the surface of the molten iron in the ladle so as to avoid oil slag generation, and the scrap steel is heated by utilizing the residual heat of the torpedo ladle to the greatest extent, so that the utilization rate of the scrap steel is improved, and the production cost of molten steel is reduced; however, this technique does not take into consideration the influence of factors such as the price of scrap and the price of hot rolled coil when adjusting the amount of scrap.
Disclosure of Invention
The invention aims to provide a method for determining the steel scrap adding amount of a torpedo tank, which mainly solves the technical problems that the benefit of adding steel scrap into the torpedo tank can not be evaluated and the optimal steel scrap adding amount can not be determined under the existing conditions, and provides decision support for the steel scrap adding amount of the torpedo tank.
The invention adopts the technical scheme that the method for determining the addition amount of the steel scraps of the torpedo tank comprises the following steps:
1) Calculating the temperature loss of molten iron saved by adding scrap into the torpedo tank, wherein the scrap can be normal-temperature scrap or preheated scrap, the scrap is added before the torpedo tank receives iron, and the temperature loss of molten iron saved by adding scrap into the torpedo tank is calculated according to formulas (1) - (4), and delta T is calculated 3 ＝ΔT 1 -ΔT 2 (1)；
ΔT 2 ＝a×m 2 +b×m+d (3)；
0≤m≤0.0375×Cn(4)；
In the formulas (1) to (4), deltaT 3 The temperature loss of molten iron for adding scrap steel into torpedo tank is shown as the unit of ℃/T and delta T 1 Theoretical molten iron temperature drop of normal temperature scrap steel is shown in the unit of ℃/T and delta T 2 Molten iron temperature drop of scrap steel for torpedo tank is in the unit of ℃/T and T 0 The unit of the temperature of molten iron before adding scrap steel is DEG C, T 1 The melting point of molten iron is expressed as the unit of DEG C, m 0 The unit is t and c, which are the amount of molten iron in the torpedo tank 0 The specific heat of molten iron is expressed as J/(kg. DEG C), c 1 The specific heat of the scrap steel is J/(kg DEG C), lambda 0 The unit is J/kg, m is the addition amount of scrap steel in the torpedo tank, the unit is t, cn is the nominal capacity of the torpedo tank, the unit is t, a is the fitting parameter, and the unit is ℃/t 3 B is a fitting parameter, and the unit is ℃/t 2 D is a fitting parameter, the unit is ℃/t, and a is equal to or less than 0.0125 x Cn when m is less than or equal to 0.0125 x Cn>0，b>0，d>0, when m>0.0125 x Cn, a<0，b>0，d>0；
2) Calculating the steelmaking cost increment of the torpedo ladle and the scrap steel, wherein the steelmaking cost increment of the torpedo ladle and the scrap steel is embodied by the converter heating cost, and is calculated according to a formula (5),
in the formula (5), gamma is the steel-making cost increment of torpedo ladle and scrap steel, and the unit is yuan/t, w 1 Is the mass content of iron in scrap steel, w 2 For the mass content of iron in the scraped molten iron slag, k is the slag-removed iron loss increased by the reduction of the temperature of the molten iron, the unit is kg/(t.DEG C), and DeltaT 2 Molten iron temperature drop of scrap steel for torpedo tank is in unit of ℃/t and m 1 Is the molten steel quantity, the unit is t, m 2 The unit of the iron turning quantity is t and c 0 The specific heat of molten iron is expressed as J/(kg.K), c 2 The specific heat of molten steel is expressed as J/(kg.K), c 3 The specific heat of pig iron is expressed as J/(kg.K), lambda 0 Is the heat of fusion of pig iron, the unit is J/kg, T 1 The melting point of molten iron is expressed as the unit of the temperature, T 6 The temperature of the molten iron after desulfurization is expressed as the unit of the temperature eta 1 Beta is the temperature rising cost of the converter, and the temperature is per/(t·) DEG C;
3) Calculating the heat recovery benefit of the torpedo ladle, wherein the heat recovery benefit is represented by the increase of the hot rolling yield, and is calculated according to formulas (6) to (9),
m blank, 1 ＝1×w 1 ×α 1 ×α 2 (8)；
m Heat, 1 ＝1×w 1 ×α 1 ×α 2 ×α 3 (9)；
In the formulas (6) to (9), rb is the heat recovery benefit of the torpedo tank after the scrap steel is added to the torpedo tank, and the unit is yuan/t and m Blank, 1 The continuous casting yield of 1t scrap steel is increased for the converter, and the unit is t and m Heat, 1 The hot rolling yield increase of 1T scrap steel is increased for the converter, and the unit is T and delta T 3 The unit of the temperature loss of the molten iron which is saved after the scrap steel is added to the torpedo ladle is ℃/T and delta T 7 Molten steel for adding scrap steel to converterTemperature drop, unit is ℃/t, w 1 Alpha is the mass content of iron in scrap steel 1 Alpha is the yield of molten steel of a converter 2 For slab yield, alpha 3 For hot rolling yield, p 1 The unit is yuan/t, p for scrap steel price 2 The unit is yuan/t and beta is the average price of the hot rolled coil 1 The unit of the variable cost of ton steel without metal material for steelmaking is yuan/t beta 2 The unit is yuan/t and beta for the variable cost of hot rolling ton steel 4 The recovery price of solid waste metal generated in steelmaking continuous casting process and hot continuous rolling process is shown as the unit of yuan/T, T 4 The unit is the temperature of molten steel at the end point of a converter, and the unit is DEG C, m 1 Is the molten steel quantity, the unit is t and c 2 The specific heat of molten steel is expressed as J/(kg. DEG C), c 1 The specific heat of the scrap steel is expressed as J/(kg. DEG C.), T 5 Is the melting point of molten steel, the unit is DEG C, lambda 1 The unit is J/kg of waste steel heat of fusion;
4) Calculating the benefit of the torpedo ladle and the scrap steel according to formulas (8) to (10),
Eb＝(m heat, 1 ×p 2 -p 1 -β 3 -γ-m Blank, 1 ×β 1 -m Heat, 1 ×β 2 +β 4 +Rb)×m (10)；
In the formula (10), eb is the benefit of torpedo tank and scrap steel, and the unit is element, m Blank, 1 The continuous casting yield of 1t scrap steel is increased for the converter, and the unit is t and m Heat, 1 The hot rolling yield of 1t scrap steel is increased for the converter, and the unit is t and p 1 The unit is yuan/t, p for scrap steel price 2 The unit is yuan/t and beta is the average price of the hot rolled coil 1 The unit of the variable cost of ton steel without metal material for steelmaking is yuan/t beta 2 The unit is yuan/t and beta for the variable cost of hot rolling ton steel 3 The cost for adding ton scrap steel of torpedo tank is shown as the unit of yuan/t and beta 4 The method is characterized in that the method comprises the steps of steel-making continuous casting and hot continuous rolling, wherein solid waste metal recovery price is generated in the steel-making continuous casting and hot continuous rolling processes, the unit is yuan/t, gamma is the steel-making cost increment of torpedo tank and scrap steel, the unit is yuan/t, rb is the heat recovery benefit of the torpedo tank after the torpedo tank and the scrap steel are added, and the unit is yuan/t;
5) Determining the adding amount of the torpedo ladle steel scraps, gradually increasing the assignment of m in the step 1), wherein the step length is more than 0 and less than or equal to 3, repeating the steps 1) to 4), and obtaining the best adding amount of the torpedo ladle steel scraps when the adding amount of the torpedo ladle steel scraps is the largest.
In the step 1), the formula (3) is divided into two cases of scrap steel preheating and scrap steel non-preheating, and parameters a, b and d are obtained by least square fitting according to the scrap steel adding amount of the torpedo ladle, the scrap steel adding amount of the torpedo ladle and the actual molten iron temperature drop from one-ladle one-pouring furnace tapping to steelmaking pouring;
in step 2), the converter heating cost beta is input required by the converter adopting a carbon heat generating agent such as graphite or coke for heat compensation, the heating cost comprises the carbon heat generating agent cost and the oxygen cost, the gain is the gas recovery increment, and the beta is calculated according to a formula (11),
in the formula (11), beta is the converter temperature rising cost, and c is the temperature per/(t.DEG C) 2 The specific heat of molten steel is expressed as J/(kg. DEG C), m 1 Is the molten steel quantity, the unit is t, w 3 The carbon for oxidation to CO is the mass content of the total carbon, w 4 To generate CO for oxidation 2 The mass content of carbon in total carbon, w 5 Is the mass content of carbon in the carbonaceous exothermic agent, delta H 1 The heat of reaction for the reaction of C and O to CO is given in kJ/kg, ΔH 2 CO formation for C and O reactions 2 Is given in kJ/kg, eta 3 Is the heat utilization rate of the carbonaceous exothermic agent, p 3 Is the price of the carbonaceous exothermic agent, the unit is yuan/t, p 4 Is oxygen price in yuan/Nm 3 ，p 5 The unit is yuan/Nm for the price of converter gas 3 ，α 4 The recovery rate of the converter gas is obtained.
The selection of the technological parameters of the method is based on:
1. molten iron temperature drop by sectionally fitting torpedo ladle and scrap steel
In the step 1), the formula (3) is based on the condition that the nominal capacity of the torpedo tank is 0.0125 times, and the relation between the adding amount of the waste steel of the torpedo tank and the temperature drop of the molten iron of the torpedo tank and the waste steel is fitted in two sections, because a certain amount of waste steel is added after the iron turning of the torpedo tank is finished, radiation heat transfer and convection heat transfer of a high-temperature lining of the torpedo tank to the environment can be hindered, the waste steel is baked and heated by utilizing waste heat of the torpedo tank, so that the heat loss of the torpedo tank is reduced, the less the heat dissipation of the torpedo tank is, the less the temperature loss of the molten iron is, but when the adding amount of the waste steel reaches a certain amount, the upper limit of the heat preservation effect of the torpedo tank is reached, namely, the waste heat recovery amount of the torpedo tank is kept unchanged after the waste heat recovery of the torpedo tank is continuously increased. Through a large number of experiments, the waste steel addition amount is just the maximum waste heat recovery of the torpedo tank when being 0.0125 times of the nominal capacity of the torpedo tank, so that the sectional fitting is carried out by taking the nominal capacity of the torpedo tank as the boundary of 0.0125 times.
2. The converter heating cost is used to embody the steel-making cost increment of torpedo ladle and scrap steel
In the step 2), the steel-making cost increment of the torpedo ladle and the scrap steel is mainly caused by the increase of slag removal iron loss of the molten steel pretreatment after the torpedo ladle and the scrap steel are added. The increase of the slag removal iron loss comprises two aspects, namely, the slag removal iron loss of the waste steel with slag is increased, the waste steel is not completely pure, a certain amount of impurities are added into a torpedo tank for melting, and after the impurities float upwards, new molten iron slag is formed with blast furnace slag, so that the slag quantity is increased, and the slag removal quantity after molten iron pretreatment is also increased, so that the desulfurization slag removal iron loss is increased; secondly, the temperature of molten iron is reduced after scrap steel is added into the torpedo ladle, the fluidity of molten iron and slag is deteriorated, and the iron carrying amount is increased in the slag removing process, so that the slag removing iron loss is increased. And slag skimming is carried out to calculate the desulfurization slag skimming cost increment of the torpedo ladle and the scrap steel. The iron in the slag is recovered after the related treatment of the molten iron slag removed by the pretreatment of molten iron, and the slag iron is used as a converter metal material instead of outsourcing scrap steel, so that the slag iron loss is not lost in physical form, but the removed iron becomes normal temperature after the treatment, the physical heat of the molten iron is lost, and the converter is required to be heated again after the molten iron is added, so that the cost is increased. Therefore, the increment of steelmaking cost caused by adding scrap steel into the torpedo ladle is embodied by the converter heating cost caused by the return generation and utilization of slag iron.
Compared with the prior art, the invention has the following positive effects: 1. the method calculates the benefit of the torpedo ladle and the scrap steel from the two aspects of the yield of the hot rolled coil which can be directly increased by the torpedo ladle and the heat of the torpedo ladle recovered by the torpedo ladle and the scrap steel, wherein the benefit of the torpedo ladle heat recovery is embodied as the saving of the temperature loss of molten iron and is converted into the converter scrap steel increasing amount so as to indirectly improve the yield of the hot rolled coil. The method takes the two conditions of scrap steel preheating and non-preheating into consideration, namely the scrap steel cost, the scrap steel adding cost, the scrap steel preheating cost, the steelmaking cost increased by the scrap steel adding of the torpedo tank, the steelmaking processing cost, the hot rolling processing cost, the converter metal loss cost, the continuous casting metal loss cost, the hot rolling metal loss cost, the metal recovery value and the hot rolling yield increase value, and the method has comprehensive influence factors, and the prediction result is more fit with reality. 2. The method can intuitively obtain the change trend of the benefit of the torpedo tank for adding the scrap steel along with the adding amount of the scrap steel in the torpedo tank, is coupled with market quotations, can determine whether the scrap steel is preheated or not according to the market quotation changes such as the price of the scrap steel, the price of a hot rolled coil and the like, and timely adjusts the adding amount of the scrap steel of the torpedo tank, thereby being beneficial to realizing the maximization of the benefit.
Detailed Description
The invention will be further described with reference to specific examples 1 to 3, as shown in tables 1 to 5
In the embodiment of the invention, a torpedo tank with nominal capacity of 320t, tapping of each tank of a blast furnace of 250t and assignment step length s of the scrap steel adding amount of the torpedo tank are taken as an example.
A method for determining the addition amount of steel scraps of a torpedo ladle comprises the following steps:
1) Calculating the temperature loss of molten iron saved by adding scrap into the torpedo tank, wherein the scrap can be normal-temperature scrap or preheated scrap, the scrap is added before the torpedo tank receives iron, and the temperature loss of molten iron saved by adding scrap into the torpedo tank is calculated according to formulas (1) - (4), and delta T is calculated 3 ＝ΔT 1 -ΔT 2 (1)；
ΔT 2 ＝a×m 2 +b×m+d (3)；
0≤m≤0.0375×Cn(4)；
In the formulas (1) to (4), deltaT 3 The temperature loss of molten iron for adding scrap steel into torpedo tank is shown as the unit of ℃/T and delta T 1 Theoretical molten iron temperature drop of normal temperature scrap steel is shown in the unit of ℃/T and delta T 2 Molten iron temperature drop of scrap steel for torpedo tank is in the unit of ℃/T and T 0 The unit of the temperature of molten iron before adding scrap steel is DEG C, T 1 The melting point of molten iron is expressed as the unit of DEG C, m 0 The unit is t and c, which are the amount of molten iron in the torpedo tank 0 The specific heat of molten iron is expressed as J/(kg. DEG C), c 1 The specific heat of the scrap steel is J/(kg DEG C), lambda 0 The unit is J/kg, m is the addition amount of scrap steel in the torpedo tank, the unit is t, cn is the nominal capacity of the torpedo tank, the unit is t, a is the fitting parameter, and the unit is ℃/t 3 B is a fitting parameter, and the unit is ℃/t 2 D is a fitting parameter, the unit is ℃/t, and a is equal to or less than 0.0125 x Cn when m is less than or equal to 0.0125 x Cn>0，b>0，d>0, when m>0.0125 x Cn, a<0，b>0，d>0；
2) Calculating the steelmaking cost increment of the torpedo ladle and the scrap steel, wherein the steelmaking cost increment of the torpedo ladle and the scrap steel is embodied by the converter heating cost, and is calculated according to a formula (5),
in the formula (5), gamma is the steel-making cost increment of torpedo ladle and scrap steel, and the unit is yuan/t, w 1 Is the mass content of iron in scrap steel, w 2 For the mass content of iron in the scraped molten iron slag, k is the slag-removed iron loss increased by the reduction of the temperature of the molten iron, the unit is kg/(t.DEG C), and DeltaT 2 Molten iron temperature drop of scrap steel for torpedo tank is in unit of ℃/t and m 1 Is the molten steel quantity, the unit is t, m 2 For turning iron in canBit t, c 0 The specific heat of molten iron is expressed as J/(kg.K), c 2 The specific heat of molten steel is expressed as J/(kg.K), c 3 The specific heat of pig iron is expressed as J/(kg.K), lambda 0 Is the heat of fusion of pig iron, the unit is J/kg, T 1 The melting point of molten iron is expressed as the unit of the temperature, T 6 The temperature of the molten iron after desulfurization is expressed as the unit of the temperature eta 1 Beta is the temperature rising cost of the converter, and the temperature is per/(t·) DEG C;
3) Calculating the heat recovery benefit of the torpedo ladle, wherein the heat recovery benefit is represented by the increase of the hot rolling yield, and is calculated according to formulas (6) to (9),
m blank, 1 ＝1×w 1 ×α 1 ×α 2 (8)；
m Heat, 1 ＝1×w 1 ×α 1 ×α 2 ×α 3 (9)；
In the formulas (6) to (9), rb is the heat recovery benefit of the torpedo tank after the scrap steel is added to the torpedo tank, and the unit is yuan/t and m Blank, 1 The continuous casting yield of 1t scrap steel is increased for the converter, and the unit is t and m Heat, 1 The hot rolling yield increase of 1T scrap steel is increased for the converter, and the unit is T and delta T 3 The unit of the temperature loss of the molten iron which is saved after the scrap steel is added to the torpedo ladle is ℃/T and delta T 7 Molten steel temperature drop for adding scrap steel into a converter is in the unit of ℃/t and w 1 Alpha is the mass content of iron in scrap steel 1 Alpha is the yield of molten steel of a converter 2 For slab yield, alpha 3 For hot rolling yield, p 1 The unit is yuan/t, p for scrap steel price 2 The unit is yuan/t and beta is the average price of the hot rolled coil 1 The unit of the variable cost of ton steel without metal material for steelmaking is yuan/t beta 2 The unit is yuan/t and beta for the variable cost of hot rolling ton steel 4 Is a steelmaking continuous casting process and a hot continuous rolling processThe recovery price of the generated solid waste metal is expressed as yuan/T, T 4 The unit is the temperature of molten steel at the end point of a converter, and the unit is DEG C, m 1 Is the molten steel quantity, the unit is t and c 2 The specific heat of molten steel is expressed as J/(kg. DEG C), c 1 The specific heat of the scrap steel is expressed as J/(kg. DEG C.), T 5 Is the melting point of molten steel, the unit is DEG C, lambda 1 The unit is J/kg of waste steel heat of fusion;
4) Calculating the benefit of the torpedo ladle and the scrap steel according to formulas (8) to (10),
Eb＝(m heat, 1 ×p 2 -p 1 -β 3 -γ-m Blank, 1 ×β 1 -m Heat, 1 ×β 2 +β 4 +Rb)×m (10)；
In the formula (10), eb is the benefit of torpedo tank and scrap steel, and the unit is element, m Blank, 1 The continuous casting yield of 1t scrap steel is increased for the converter, and the unit is t and m Heat, 1 The hot rolling yield of 1t scrap steel is increased for the converter, and the unit is t and p 1 The unit is yuan/t, p for scrap steel price 2 The unit is yuan/t and beta is the average price of the hot rolled coil 1 The unit of the variable cost of ton steel without metal material for steelmaking is yuan/t beta 2 The unit is yuan/t and beta for the variable cost of hot rolling ton steel 3 The cost for adding ton scrap steel of torpedo tank is shown as the unit of yuan/t and beta 4 The method is characterized in that the method comprises the steps of steel-making continuous casting and hot continuous rolling, wherein solid waste metal recovery price is generated in the steel-making continuous casting and hot continuous rolling processes, the unit is yuan/t, gamma is the steel-making cost increment of torpedo tank and scrap steel, the unit is yuan/t, rb is the heat recovery benefit of the torpedo tank after the torpedo tank and the scrap steel are added, and the unit is yuan/t;
5) Determining the adding amount of the torpedo ladle steel scraps, gradually increasing the assignment of m in the step 1), wherein the step length is 2, repeating the steps 1) to 4), and obtaining the best adding amount of the torpedo ladle steel scraps when the adding benefit of the torpedo ladle steel scraps is maximum.
TABLE 1 thermal equilibrium parameters of the examples of the invention
TABLE 2 Process yield and processing cost parameters for the examples of the invention
| Category(s) | α 1 | α 2 | α 3 | β 1 Meta/t | β 2 Meta/t | β 3 Meta/t |
| Example 1 | 96.8％ | 98％ | 98.48％ | 200 | 177 | 22.5 |
| Example 2 | 96.8％ | 98％ | 98.48％ | 200 | 177 | 22.5 |
| Example 3 | 96.8％ | 98％ | 98.48％ | 200 | 177 | 22.5 |
TABLE 3 physical Properties and price parameters of examples of the invention
| Category(s) | w 1 | T 1 ,℃ | T 5 ,℃ | p 1 Meta/t | p 2 Meta/t | β 4 Meta/t |
| Example 1 | 95％ | 1099 | 1529 | 3361 | 4863 | 50 |
| Example 2 | 95％ | 1099 | 1529 | 3361 | 4463 | 50 |
| Example 3 | 95％ | 1099 | 1529 | 3361 | 4190 | 50 |
TABLE 4 blast furnace and steelmaking process parameters according to embodiments of the invention
| Category(s) | m 0 ,t | m 1 ,t | w 2 | T 0 ,℃ | T 4 ,℃ | T 6 ,℃ | k,kg/(t·℃) | η 1 | Beta, meta/t |
| Example 1 | 250 | 268 | 50％ | 1490 | 1630 | 1350 | 0.25 | 95.8％ | 0.62 |
| Example 2 | 250 | 268 | 50％ | 1490 | 1630 | 1350 | 0.25 | 95.8％ | 0.62 |
| Example 3 | 250 | 268 | 50％ | 1490 | 1630 | 1350 | 0.25 | 95.8％ | 0.62 |
TABLE 5 benefit of the torpedo tank and scrap according to the embodiment of the invention
As shown in tables 1 to 5, the heat balance parameters, the process yield and the processing cost parameters, the physical properties and the price parameters, the blast furnace and steelmaking process parameters, and the benefits of scrap addition of torpedo ladle in examples 1 to 3. Examples 1 to 3 differ in the price of the hot rolled coil, example 1> example 2> example 3. For example 1, i.e. when the price difference between the hot rolled coil and the scrap steel is large, the benefit of adding the scrap steel into the torpedo ladle is gradually increased along with the increase of the adding amount of the scrap steel, and the more and better the scrap steel is added; for example 2, when the price difference between the hot rolled coil and the scrap steel is common, the benefit of the torpedo ladle for adding the scrap steel is increased and then reduced along with the increase of the adding amount of the scrap steel; for example 3, there was no economic benefit in torpedo ladle charging with scrap as the price difference between hot rolled coil and scrap was further reduced, and the more scrap was charged, the more the depletion was. According to the results of Table 5, the optimum torpedo ladle scrap addition amount of example 1 was 10t, the optimum torpedo ladle scrap addition amount of example 2 was 6t, and the optimum torpedo ladle scrap addition amount of example 3 was 0t. By judging whether the benefit is greater than 0 and the change trend of the benefit along with the addition of the scrap steel, a decision can be provided for the addition of the scrap steel of the torpedo tank.
In addition to the embodiments described above, other embodiments of the invention are possible. All technical schemes formed by equivalent substitution or equivalent transformation fall within the protection scope of the invention.
Claims (3)
1. The method for determining the addition amount of the torpedo ladle scrap steel is characterized by comprising the following steps of:
1) Calculating the temperature loss of the molten iron saved by adding scrap steel into the torpedo tank, wherein the scrap steel can be normal-temperature scrap steel or preheated scrap steel, the scrap steel is added before the torpedo tank receives iron, the temperature loss of the molten iron saved by adding scrap steel into the torpedo tank is calculated according to formulas (1) to (4),
ΔT 3 ＝ΔT 1 -ΔT 2 (1)；
ΔT 2 ＝a×m 2 +b×m+d (3)；
0≤m≤0.0375×Cn (4)；
in the formulas (1) to (4), deltaT 3 The temperature loss of molten iron for adding scrap steel into torpedo tank is shown as the unit of ℃/T and delta T 1 Theoretical molten iron temperature drop of normal temperature scrap steel is shown in the unit of ℃/T and delta T 2 Molten iron temperature drop of scrap steel for torpedo tank is in the unit of ℃/T and T 0 The unit of the temperature of molten iron before adding scrap steel is DEG C, T 1 The melting point of molten iron is expressed as the unit of DEG C, m 0 The unit is t and c, which are the amount of molten iron in the torpedo tank 0 The specific heat of molten iron is expressed as J/(kg. DEG C), c 1 The specific heat of the scrap steel is J/(kg DEG C), lambda 0 The unit is J/kg, m is the addition amount of scrap steel in the torpedo tank, the unit is t, cn is the nominal capacity of the torpedo tank, the unit is t, a is the fitting parameter, and the unit is ℃/t 3 B is a fitting parameter, and the unit is ℃/t 2 D is a fitting parameter, the unit is ℃/t, and a is equal to or less than 0.0125 x Cn when m is less than or equal to 0.0125 x Cn>0，b>0，d>0, when m>0.0125 x Cn, a<0，b>0，d>0；
2) Calculating the steelmaking cost increment of the torpedo ladle and the scrap steel, wherein the steelmaking cost increment of the torpedo ladle and the scrap steel is embodied by the converter heating cost, and is calculated according to a formula (5),
in the formula (5), gamma is the steel-making cost increment of torpedo ladle and scrap steel, and the unit is yuan/t, w 1 Is the mass content of iron in scrap steel, w 2 For the mass content of iron in the scraped molten iron slag, k is the slag-removed iron loss increased by the reduction of the temperature of the molten iron, the unit is kg/(t.DEG C), and DeltaT 2 Molten iron temperature drop of scrap steel for torpedo tank is in unit of ℃/t and m 1 Is the molten steel quantity, the unit is t, m 2 The unit of the iron turning quantity is t and c 0 The specific heat of molten iron is expressed as J/(kg.K), c 2 The specific heat of molten steel is expressed as J/(kg.K), c 3 The specific heat of pig iron is expressed as J/(kg.K), lambda 0 Is the heat of fusion of pig iron, the unit is J/kg, T 1 The melting point of molten iron is expressed as the unit of the temperature, T 6 The temperature of the molten iron after desulfurization is expressed as the unit of the temperature eta 1 Beta is the temperature rising cost of the converter, and the temperature is per/(t·) DEG C;
3) Calculating the heat recovery benefit of the torpedo ladle, wherein the heat recovery benefit is represented by the increase of the hot rolling yield, and is calculated according to formulas (6) to (9),
m blank, 1 ＝1×w 1 ×α 1 ×α 2 (8)；
m Heat, 1 ＝1×w 1 ×α 1 ×α 2 ×α 3 (9)；
In the formulas (6) to (9), rb is the heat recovery benefit of the torpedo tank after the scrap steel is added to the torpedo tank, and the unit is yuan/t and m Blank, 1 The continuous casting yield of 1t scrap steel is increased for the converter, and the unit is t and m Heat, 1 The hot rolling yield increase of 1T scrap steel is increased for the converter, and the unit is T and delta T 3 Molten iron saved after scrap steel is added to torpedo ladleTemperature loss in units of ℃/T, deltaT 7 Molten steel temperature drop for adding scrap steel into a converter is in the unit of ℃/t and w 1 Alpha is the mass content of iron in scrap steel 1 Alpha is the yield of molten steel of a converter 2 For slab yield, alpha 3 For hot rolling yield, p 1 The unit is yuan/t, p for scrap steel price 2 The unit is yuan/t and beta is the average price of the hot rolled coil 1 The unit of the variable cost of ton steel without metal material for steelmaking is yuan/t beta 2 The unit is yuan/t and beta for the variable cost of hot rolling ton steel 4 The recovery price of solid waste metal generated in steelmaking continuous casting process and hot continuous rolling process is shown as the unit of yuan/T, T 4 The unit is the temperature of molten steel at the end point of a converter, and the unit is DEG C, m 1 Is the molten steel quantity, the unit is t and c 2 The specific heat of molten steel is expressed as J/(kg. DEG C), c 1 The specific heat of the scrap steel is expressed as J/(kg. DEG C.), T 5 Is the melting point of molten steel, the unit is DEG C, lambda 1 The unit is J/kg of waste steel heat of fusion;
4) Calculating the benefit of the torpedo ladle and the scrap steel according to formulas (8) to (10),
Eb＝(m heat, 1 ×p 2 -p 1 -β 3 -γ-m Blank, 1 ×β 1 -m Heat, 1 ×β 2 +β 4 +Rb)×m (10)；
In the formula (10), eb is the benefit of torpedo tank and scrap steel, and the unit is element, m Blank, 1 The continuous casting yield of 1t scrap steel is increased for the converter, and the unit is t and m Heat, 1 The hot rolling yield of 1t scrap steel is increased for the converter, and the unit is t and p 1 The unit is yuan/t, p for scrap steel price 2 The unit is yuan/t and beta is the average price of the hot rolled coil 1 The unit of the variable cost of ton steel without metal material for steelmaking is yuan/t beta 2 The unit is yuan/t and beta for the variable cost of hot rolling ton steel 3 The cost for adding ton scrap steel of torpedo tank is shown as the unit of yuan/t and beta 4 The method is characterized in that the method comprises the steps of steel-making continuous casting and hot continuous rolling, wherein solid waste metal recovery price is generated in the steel-making continuous casting and hot continuous rolling processes, the unit is yuan/t, gamma is the steel-making cost increment of torpedo tank and scrap steel, the unit is yuan/t, rb is the heat recovery benefit of the torpedo tank after the torpedo tank and the scrap steel are added, and the unit is yuan/t;
5) Determining the adding amount of the torpedo ladle steel scraps, gradually increasing the assignment of m in the step 1), wherein the step length is more than 0 and less than or equal to 3, repeating the steps 1) to 4), and obtaining the best adding amount of the torpedo ladle steel scraps when the adding amount of the torpedo ladle steel scraps is the largest.
2. The method for determining the scrap addition amount of the torpedo ladle according to claim 1, wherein the formula (3) is characterized in that parameters a, b and d are obtained by least square fitting according to the scrap addition amount of the torpedo ladle, the scrap addition amount of the torpedo ladle and the actual molten iron temperature drop from one-ladle one-shot blast furnace tapping to steelmaking pouring.
3. The method for determining the steel scrap addition amount of the torpedo ladle according to claim 1, wherein the temperature rising cost beta of the converter is input required for supplementing heat by adopting a carbon heat generating agent such as graphite or coke and the like, the temperature rising cost comprises the cost of the carbon heat generating agent and the cost of oxygen, the gain is the gas recovery increment amount, and beta is calculated according to a formula (11),
in the formula (11), beta is the converter temperature rising cost, and c is the temperature per/(t.DEG C) 2 The specific heat of molten steel is expressed as J/(kg. DEG C), m 1 Is the molten steel quantity, the unit is t, w 3 The carbon for oxidation to CO is the mass content of the total carbon, w 4 To generate CO for oxidation 2 The mass content of carbon in total carbon, w 5 Is the mass content of carbon in the carbonaceous exothermic agent, delta H 1 The heat of reaction for the reaction of C and O to CO is given in kJ/kg, ΔH 2 CO formation for C and O reactions 2 Is given in kJ/kg, eta 3 Is the heat utilization rate of the carbonaceous exothermic agent, p 3 Is the price of the carbonaceous exothermic agent, the unit is yuan/t, p 4 Is oxygen price in yuan/Nm 3 ，p 5 The unit is yuan/Nm for the price of converter gas 3 ，α 4 The recovery rate of the converter gas is obtained.
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