Description:

TECHNICAL FIELD
The present disclosure, in general, relates to the field of metallurgy. Particularly, but not exclusively, the present disclosure relates to burdening (charging) of a blast furnace. Further, embodiments of the present disclosure relate to a method for determining optimum flux requirement for burdening process in the blast furnace.

BACKGROUND OF THE DISCLOSURE
A blast furnace is a metallurgical furnace employed to produce liquid metal. Blast furnaces are employed to produce pig iron from iron ore, which is later processed into steel. To produce iron in the blast furnace, solid raw materials are charged from the top of the blast furnace, while a flow of air is introduced under pressure into the furnace. The pressurized high temperature air, including reducing gases, ascends in the blast furnace, interacts with the solid raw material charged from the top, to convert the solid raw material into liquid products such as molten metal and slag.

The solid raw material, that is charged into the blast furnace is also called as ‘burdening process or simply burden’. The burden mainly includes three categories of raw materials, namely, metallic materials, fuel material and fluxing material. Metallic materials consist of prepared burden such as sinter, pellets, briquettes, lump iron ore and the like. Metallics provide iron oxide and gangue material (such as silica, alumina, alkali, and the like) to iron making process in the blast furnace. The iron oxides, while descending in the blast furnace, get reduced to iron and form liquid metal (hot metal or liquid steel), whereas the gangue materials get converted into slag. Further, fuel material includes solid coke and auxiliary fuel material used to lower the solid coke requirement for the iron making process. Fluxing material includes material such as limestone, pyroxenite, dolomite, quartzite, and the like. Fluxing material binds the incoming gangue materials into a low melting slag, which can be handled conveniently through the blast furnace, without increasing fuel demand of the iron making process.

The burden is charged as alternating layers of coke and iron-bearing materials into the blast furnace. Hot blast of air, which is at a temperature of 1100 ? to 1200 ? is blown through tuyeres from the bottom of the furnace. The hot blast of air may be enriched with oxygen, in case of furnaces with coal injection feature, for maintaining flame temperature of gases burning in front of the tuyeres. The hot blast gasifies carbon bearing fuel material to carbon monoxide, resulting in a release of abundant heat through exothermic reaction. The released heat increases flame temperature of the gas to 2100 ? to 2300 ?. The hot blast of air at such high temperature ascends to the top of the blast furnace, while heating and reducing the iron-bearing burden to liquid metal and slag. Combustion of solid coke and conversion of solid burden to liquids create voidage in the blast furnace and drives the blast furnace into continuous production of hot metal. Upon accumulation of a predetermined quantity of liquid metal and slag in hearth of the blast furnace, the liquid metal and slag is tapped through tapholes of the blast furnace, into torpedo ladles.

Alumina (Al2O3) content of the burden supplied to the blast furnace, majorly influences chemical composition of the slag (also called as slag chemistry). Further, as illustrated in Figure 1, mass percentage of alumina in iron-ore supplied to the blast furnace has been steadily increasing. Particularly, alumina content in the supplied iron-ore has relatively increased by 35 percent, from an absolute level of 2 percent (to about 2.7%. Moreover, future estimates suggest that the alumina content in the supplied iron-ore will further rise significantly. To compensate for such increased alumina content, blast furnace operators tend to over-flux (supply excess fluxing material) the blast furnace, resulting in a safe slag regime as shown in Figure 2. As can be seen in figure 2, slag rate is a function of alumina load in raw materials supplied to the blast furnace, and an increase in alumina load in raw materials supplied to the blast furnace, results in an increase in slag rate measured in terms of kilogram per tonne of hot metal (kg/thm). Such increased slag rate, increases consumption of fluxing material, resulting in escalation of costs associated with production of hot metal. Hence, it is desirable to reduce such excess slag generation. Further, as illustrated in Figure 3, operators tend to frequently over-flux (almost around 70 percent), thereby resulting in an increased slag rate. Such increased slag rate generates around 15 to 20 kgs of excess slag for every tonne of hot metal produced. Accordingly, for efficient operation of the blast furnace, it is desirable that an optimum quantity of fluxing material is consumed, relative to a unit quantity of hot metal produced. There is also a requirement to reduce wastage and over consumption of burden, for unit quantity of hot metal produced, thereby reducing production costs.

The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the conventional method of burdening the blast furnace.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of the conventional methods of burdening are overcome by a method as claimed and additional advantages are provided through the method as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In one non-limiting embodiment of the present disclosure, a method for determining optimum flux requirement for burdening process in a blast furnace is disclosed. The method includes receiving, by a control unit (CU), composition of raw materials to be supplied to the blast furnace and a desired slag chemistry for the composition of raw materials. The method further includes determining, by the control unit, representative average of chemistry values for each raw material to be supplied to the blast furnace. The representative average is determined based on an exponential moving average (EMA) of a chemical composition of raw materials supplied in a plurality of previous burdening processes of the blast furnace. The method further includes determining, by the control unit, alumina (Al2O3) load going into the blast furnace. The alumina (Al2O3) load is determined through the composition of raw materials to be supplied into the blast furnace based on determined representative average of chemistry values for each raw material. The method furthermore includes determining, by the control unit, minimum slag rate based on the desired slag chemistry and alumina load going into the blast furnace. The method also includes determining, by the control unit, minimum quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) based on the desired slag chemistry, and then predicting an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry.

In an embodiment of the present disclosure, the optimum quantity of fluxing material is determined for at least one of limestone, dolomite, pyroxenite and quartzite in terms of mass percentage.

In an embodiment of the present disclosure, the method includes comparing, by the control unit, produced slag chemistry with the desired slag chemistry. Such comparison is performed to indicate variation in composition of the slag based on the predicted optimum quantity of fluxing material supplied to the burdening process.

In an embodiment of the present disclosure, the method includes adjusting, by the control unit, the predicted optimum quantity of fluxing material. Such adjustment is performed to minimize variation between the produced slag chemistry and the desired slag chemistry, in a subsequent burdening process of the blast furnace.

In an embodiment of the present disclosure, the desired slag chemistry received by the control unit is based on parameters including at least one of the minimum slag rate, basicity of the slag, mass percentage of at least one of Al2O3, CaO, MgO and SiO2, required in unit quantity of the slag.

In an embodiment of the present disclosure, the raw material includes fuel material, iron-bearing material, and fluxing material for the burdening process.

In an embodiment of the present disclosure, the fuel material includes at least one of coke, pulverized coal, and coal tar.

In an embodiment of the present disclosure, the iron-bearing material includes at least one of sinter, pellet, iron ore and briquettes.

In an embodiment of the present disclosure, the quantity of mass percentage of CaO to be supplied to the blast furnace is determined based on CaO obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of CaO required for the desired slag chemistry.

In an embodiment of the present disclosure, the quantity of mass percentage of MgO to be supplied to the blast furnace is determined based on MgO obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of MgO required for the desired slag chemistry.

In an embodiment of the present disclosure, the quantity of mass percentage of SiO2 to be supplied to the blast furnace is determined based on SiO2 obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of SiO2 required for the desired slag chemistry.

In another non-limiting embodiment of the present disclosure, a system for determining optimum flux requirement for burdening process in a blast furnace is disclosed. The system includes a control unit (CU) which is configured to firstly receive composition of raw materials to be supplied to the blast furnace and a desired slag chemistry for the composition of raw materials. The control unit then determines representative average of chemistry values for each raw material to be supplied to the blast furnace. The representative average is determined based on an exponential moving average (EMA) of a chemical composition of raw materials supplied in a plurality of previous burdening processes of the blast furnace. The control unit also determines alumina (Al2O3) load going into the blast furnace. The alumina (Al2O3) load is determined through the composition of raw materials to be supplied into the blast furnace based on determined representative average of chemistry values for each raw material. Further, the control unit determines minimum slag rate based on the desired slag chemistry and alumina load going into the blast furnace. The control unit is further configured to determine minimum quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) based on the desired slag chemistry and predict an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry.

In an embodiment of the present disclosure, the system includes a memory unit. The memory unit stores the exponential moving average (EMA) of the chemical composition of raw materials supplied in the plurality of previous burdening processes of the blast furnace.

In an embodiment of the present disclosure, the system includes a user interface unit. The user interface unit is configured to enable a user to input the composition of raw materials to be supplied to the blast furnace and to input the desired slag chemistry for the composition of raw materials.

In an embodiment of the present disclosure, the system is integrated with a lab management system from which the chemical composition is programmatically captured and is utilized by the system of the present disclosure. The lab management system is a repository of chemical composition of all the raw materials and product (hot metal slag).

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

Figure 1 is a graph illustrating mass percentage of alumina in iron-ore supplied to a blast furnace by a conventional burdening process.

Figure 2 is a graph illustrating increase in slag rate with increase in alumina load in raw materials supplied to the blast furnace by a conventional burdening process.

Figure 3 is a graph illustrating percentage instances of under-fluxing, optimum-fluxing and over-fluxing in the blast furnace by a conventional burdening process.

Figure 4 is a flow chart of a method for determining optimum flux requirement for burdening process in a blast furnace, in accordance with an exemplary embodiment of the present disclosure.

Figure 5 is a graph illustrating percentage of sinter CaO for various representative average determination methods, in accordance with an exemplary embodiment of the present disclosure.

Figure 6 illustrates a system for determining optimum flux requirement for burdening process in the blast furnace in accordance with the method of the present disclosure.

Figure 7 is a flow chart illustrating a process of optimization of quantity of fluxing material supplied to a burdening process of the blast furnace, in accordance with an embodiment of the present disclosure.

Figure 8 is a flow chart illustrating the process of Figure 7, as implemented by the system of Figure 6, in accordance with an exemplary embodiment of the present disclosure.

The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system and the method illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by the way of example in the figures and will be described below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover non-exclusive inclusions, such that a device, assembly, mechanism, system, method that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

Embodiments of the present disclosure disclose a method for determining optimum flux requirement for burdening process in a blast furnace. The method includes receiving, by a control unit (CU), composition of raw materials to be supplied to the blast furnace and a desired slag chemistry for the composition of raw materials. The method further includes determining, by the control unit, representative average of chemistry values for each raw material to be supplied to the blast furnace. The representative average is determined based on an exponential moving average (EMA) of a chemical composition of raw materials supplied in a plurality of previous burdening processes of the blast furnace. The method further includes determining, by the control unit, alumina (Al2O3) load going into the blast furnace. The alumina (Al2O3) load is determined through the composition of raw materials to be supplied into the blast furnace based on determined representative average of chemistry values for each raw material. The method further includes determining, by the control unit, minimum slag rate based on the desired slag chemistry and alumina load going into the blast furnace. The method further includes determining, by the control unit, minimum quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) based on the desired slag chemistry. The method further includes predicting, by the control unit, an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry. Further, a system for determining optimum flux requirement for burdening process in the blast furnace, is also disclosed.

The term ‘burdening process’ (also referred to as ‘burdening’ hereinafter) as used herein refers to a charging or feeding of raw material into the blast furnace. The term ‘burden’ as used herein refers to a required weight of each raw material, that is essential for achieving a desired chemistry of hot metal and slag. The phrase ‘desired slag chemistry’ or ‘target slag chemistry’ as used herein includes parameters such as, but not limited to, quantity, quality and chemical composition of slag generated per unit tonne of hot metal produced by the blast furnace. Further, the ‘desired slag chemistry’ or ‘target slag chemistry’ as used herein, may also include parameters such as, but not limited to, slag generation rate, chemical composition of the slag including percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) in unit quantity of slag, basicity of the slag and the like. Desired slag chemistry depends upon parameters such as, but not limited to, chemical composition, quality and quantity of the raw materials utilized in burdening process of the blast furnace. In an embodiment, the desired slag chemistry may be determined based on raw material chemistry that may be determined in real-time, and is dependent on process conditions, alumina content in iron ore supplied to the blast furnace, timely tapping of hot metal, composition of the slag produced in the blast furnace and the like. The desired slag chemistry may be expressed and measured in terms of minimum slag rate, composition of at least one of alumina (Al2O3), calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) required in unit quantity of slag generated in the blast furnace, basicity of the slag and the like. Further, the ‘desired slag chemistry’ may be expressed and measured as a lowest slag rate possible with given quality, quantity, and chemical composition of raw materials.

The disclosure is described in the following paragraphs with reference to Figures 1 to 8. In the figures, the same element or elements which have same functions are indicated by the same reference signs. It is to be noted that, the blast furnace is not illustrated in the figures for the purpose of simplicity. One skilled in the art would appreciate that the method and the system as disclosed in the present disclosure may be used in any blast furnace including, but not limited to, blast furnaces configured to produce iron, lead, copper, and other metals.

Figure 4 is an exemplary embodiment of the present disclosure illustrating a flow chart of the method (100) for determining optimum flux requirement for burdening process in a blast furnace. In an embodiment, the method (100) may be implemented in any blast furnace configured to chemically reduce and physically convert iron ores into liquid iron (molten metal) in steelmaking. The term ‘optimum flux requirement’ as used herein refers to a minimum essential quantity of fluxing material required to achieve the desired slag chemistry. The minimum essential quantity of fluxing material may be determined in terms of mass percentage of the fluxing material utilized in the burdening process.

The order in which the method (100) is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the method (100). Additionally, individual blocks may be deleted from the method (100) without departing from the scope of the subject matter described herein.

As depicted at block 101, the method (100) includes receiving, by a control unit (CU) (201) (as can be seen in Figure 6), composition of raw materials to be supplied to the blast furnace. The term ‘raw material’ as used herein includes materials such as, but not limited to, fuel material, iron-bearing material such as iron ore, and fluxing material supplied to the blast furnace during the burdening process. Fuel material includes materials such as, but not limited to, coke, pulverized coal, and coal tar. Iron-bearing materials include materials such as, but not limited to, sinter, pellet, iron ore, briquettes. Fluxing material includes consumable flux materials such as, but not limited to, limestone, dolomite, pyroxenite, quartzite and the like. The method (101) further includes receiving a desired slag chemistry for the received composition of raw materials. The desired slag chemistry received by the control unit (201) may be expressed in parameters including at least one of the minimum slag rate, basicity of the slag, mass percentage of at least one of Al2O3, CaO, MgO and SiO2, required in a unit quantity of the slag.

In an embodiment, the composition of raw materials to be supplied to the blast furnace, may be measured and obtained by a plurality of sensors. However, the composition of raw materials may also be obtained from laboratories that test the raw materials and may be input into the system (200) for determining optimum flux requirement for burdening process in the blast furnace. The desired slag chemistry received by the control unit (201) may be provided by an operator operating the blast furnace. However, the desired slag chemistry may also be preset in the system (200).

As depicted at block 102, the method (100) includes determining, by the control unit (201), representative average of chemistry values for each raw material to be supplied to the blast furnace. The representative average may be determined based on an exponential moving average (EMA) of a chemical composition of raw materials, as illustrated in Figure 5. The EMA may be determined based on chemical composition of raw materials, supplied in a plurality of previous burdening processes of the blast furnace. In an exemplary embodiment, the EMA may be determined based on chemical composition of raw materials, supplied in previous three burdening processes of the blast furnace.

In an embodiment, the desired slag chemistry may be determined based on at least three latest available values of chemical composition of raw materials. The three latest values of chemical composition of raw materials may be determined by adopting an exponential moving average (EMA) technique that takes real-time data into consideration. The determined chemical composition may be stored in a database of the system (200). The EMA technique considers weighted averages for determination of chemical composition. The EMA technique emphasizes on latest values of chemical composition of raw materials and is best suited for a continuous process, such as, but not limited to, production of hot metal in the blast furnace. As can be seen in Figure 5, traditional practice of taking simple average of chemical composition of raw materials, results in excessive sinter CaO percentage. However, the EMA technique responds appropriately to variation in chemical composition of raw materials.

As depicted at block 103, the method (100) includes determining, by the control unit (201), alumina (Al2O3) load going into the blast furnace. The alumina (Al2O3) load may be determined through the composition of raw materials to be supplied into the blast furnace. As described in the previous paragraph, the composition of raw materials may be established based on determined representative average of chemistry values for each raw material.

As depicted at block 104, the method (100) includes determining, by the control unit (201), minimum slag rate (slag that needs to be generated (measured in kilograms) for every tonne of hot metal produced in the blast furnace). The minimum slag rate may be determined based on the desired slag chemistry and the alumina load going into the blast furnace.

As depicted at block 105, the method (100) includes determining, by the control unit (201), minimum quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) based on the desired slag chemistry. The minimum quantity of mass percentage of CaO, MgO, and SiO2, is the minimum essential quantity required to achieve the desired slag chemistry.

In an embodiment, the quantity of mass percentage of CaO to be supplied to the blast furnace is determined based on CaO obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of CaO required for the desired slag chemistry. The mass percentage of CaO to be supplied to the blast furnace may be fulfilled by supplying at least one of limestone and dolomite, based on availability. Further, the quantity of mass percentage of MgO to be supplied to the blast furnace is determined based on MgO obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of MgO required for the desired slag chemistry. The mass percentage of MgO to be supplied to the blast furnace may be fulfilled by supplying pyroxenite. Further, for instance, when dolomite has been used to fulfill CaO requirement, at least a portion MgO required may be fulfilled by the supplied dolomite. Furthermore, the quantity of mass percentage of SiO2 to be supplied to the blast furnace is determined based on SiO2 obtained from all the raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of SiO2 required for the desired slag chemistry. The mass percentage of SiO2 to be supplied to the blast furnace may be fulfilled by supplying quartzite. Further, for instance, when pyroxenite has been used to fulfill MgO requirement, at least a portion SiO2 required may be fulfilled by the supplied quartzite.

As depicted at block 106, the method (100) includes predicting, by the control unit (201), an optimum quantity of fluxing material for the burdening process. The predicted optimum quantity of fluxing material is the minimum essential quantity of fluxing material required to obtain the determined minimum slag rate and the desired slag chemistry. The optimum quantity of fluxing material may be determined for at least one of limestone, dolomite, pyroxenite and quartzite in terms of mass percentage.

In an embodiment, the method (100) includes comparing, by the control unit (201), produced slag chemistry with the desired slag chemistry. The comparison between the produced slag chemistry and the desired slag chemistry may be made to indicate variation in composition of the slag, based on the predicted optimum quantity of fluxing material supplied to the burdening process. The produced slag chemistry, in a manner similar to that of the desired slag chemistry, may be expressed and measured in terms of minimum slag rate, composition of at least one of alumina (Al2O3), calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) required in unit quantity of slag generated in the blast furnace, basicity of the slag and the like.

In an embodiment, the method (100) includes adjusting, by the control unit (201), the predicted optimum quantity of fluxing material. Adjusting is performed to minimize variation between the produced slag chemistry and the desired slag chemistry, in a subsequent burdening process of the blast furnace.

Figure 6 is an exemplary embodiment of the present disclosure illustrating a system (200) for determining optimum flux requirement for burdening process in the blast furnace. The system (200) includes a control unit (CU) (201) configured to determine optimum flux requirement for burdening process in the blast furnace. The system includes a composition determination module (202), an average determination module (203), an alumina determination module (204), a slag rate determination module (205), a flux determination module (206) and an optimization module (207). In addition to the above, the system (200) may also include a memory unit (208) and a user interface unit (209).

The composition determination module (202) may be configured to receive composition of raw materials to be supplied to the blast furnace and a desired slag chemistry for the received composition of raw materials. The average determination module (203) may be configured to determine representative average of chemistry values for each raw material to be supplied to the blast furnace. The representative average may be determined based on an exponential moving average (EMA) of a chemical composition of raw materials supplied in a plurality of previous burdening processes of the blast furnace. The alumina determination module (204) may be configured to determine alumina (Al2O3) load going into the blast furnace. The alumina (Al2O3) load may be determined through the composition of raw materials to be supplied into the blast furnace, which has been previously determined by the composition determination module (202). Further, the alumina (Al2O3) load may be determined based on determined representative average of chemistry values for each raw material, which has been previously determined by the average determination module (203).

The slag rate determination module (205) may be configured to determine minimum slag rate based on the desired slag chemistry and alumina load going into the blast furnace. Further, the flux determination module (206) may be configured to determine minimum quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) based on the desired slag chemistry. The optimization module (207) may be configured to predict an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry.

In an embodiment, the control unit (201) may be configured to compare produced slag chemistry with the desired slag chemistry. The comparison between the produced slag chemistry and the desired slag chemistry may be made to indicate variation in composition of the slag, based on the predicted optimum quantity of fluxing material supplied to the burdening process. Further, the control unit (201) may also be configured to adjust the predicted optimum quantity of fluxing material. Adjusting is performed to minimize variation between the produced slag chemistry and the desired slag chemistry, in a subsequent burdening process of the blast furnace.

In an embodiment, the memory unit (208) may be configured to store the exponential moving average (EMA) of the chemical composition of raw materials, that were supplied in the plurality of previous burdening processes of the blast furnace. The memory (208) may also be configured to store various parameters and averages input by a user through the user interface unit (209) and determined by the plurality of modules (202 to 207) of the control unit (201).

In an embodiment, the user interface unit (209) may be configured to enable a user to input the composition of raw materials to be supplied to the blast furnace. The user interface unit (209) may also be configured to input the desired slag chemistry for the received/input composition of raw materials.

In an embodiment of the present disclosure, the system (200) may be integrated with a lab management system from which the chemical composition is programmatically captured and is utilized by the system (200) of the present disclosure. The lab management system is a repository of chemical composition of all the raw materials and product (hot metal slag).

Figure 7 is a flow chart illustrating a process (300) of optimization of quantity of fluxing material supplied to the burdening process. The process (300) is a combination of the steps of comparing the produced slag chemistry with the desired slag chemistry and adjusting the predicted optimum quantity of fluxing material. The process (300) begins with the step of providing desired slag chemistry for the received composition of raw materials, as depicted at 301. The process (300) further includes determining minimum slag rate, alumina load and minimum quantity of CaO, MgO and SiO2, required for achieving the desired slag chemistry with the received composition of raw materials, as depicted at 302. The process (300) further includes predicting an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry, as depicted at 303. The process (300) further includes comparing the produced slag chemistry with the desired slag chemistry, as depicted at 304. The comparison between the produced slag chemistry and the desired slag chemistry, reveals variation in composition of the slag, based on the predicted optimum quantity of fluxing material supplied to the burdening process. The process (300) may be terminated when there is no variation in composition of the slag or when the variation in composition of the slag is within a predefined range, as depicted at 305. The process (300) may be continued/repeated, when the variation in composition of the slag exceeds the predefined range, as depicted at 306. The process (300) may be repeated until the variation in composition of the slag is nil or when the variation in composition of the slag is within the predefined range. The control unit (201) may be configured to adjust the predicted optimum quantity of fluxing material, to minimize the variation in composition of the slag.

Figure 8 is a flow chart illustrating a process (400) of optimization of quantity of fluxing material supplied to the burdening process, as implemented by the modules (202-207) included in the system (200) of Figure 6.
As depicted at block 401, the composition determination module (202), upon receiving composition of raw materials, is configured to determine individual mass percentage quantities of alumina (Al2O3), calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2), to be supplied to the blast furnace. The composition determination module (202) may be configured to determine said individual mass percentage quantities by methods including, but not limited to, chemical analysis of a sample of the slag from the blast furnace, or empirically by employing an equation recited below:
Individual mass percentage quantities of CaO,SiO_2,MgO,?Al?_2 O_3= "Oxide from Metallics+ Coke + Coal - Flue dust (excluding flux) "
Further, as depicted at block 402, the alumina determination module (204) may be configured to determine alumina (Al2O3) load going into the blast furnace by employing the equation recited below:
"Total " ?Al?_2 O_3 " load (kg/thm) = base " ?Al?_2 O_3 " + ? Ai *" (? Al?_2 O_3 "%" )/100 " "
"where " A_i " is fluxes measured in kg/thm"
As depicted at block 403, the slag rate determination module (205) determines a minimum slag rate (also referred to as theoretical minimum slag rate) based on the desired slag chemistry and alumina load going into the blast furnace. The slag rate determination module (205) determines minimum slag rate by employing an equation recited below:
Theoretical Minimum Slag Rate=(Total ?Al?_2 O_3 load *100)/(Aim ?Al?_2 O_3%)

As depicted at block 404, the average determination module (203) is configured to determine mass percentage values for each raw material to be supplied to the blast furnace. At first, the average determination module (203) determines mass percentage values of alumina (Al2O3) and magnesium oxide (MgO) (in terms of kg/thm) based on the determined theoretical minimum slag rate. Further, the flux determination module (206) is configured to determine minimum quantity of mass percentage values of calcium oxide (CaO) and silicon dioxide (SiO2) to be supplied to the blast furnace, based on the determined theoretical minimum slag rate. The flux determination module (206) employs equations as recited below:
Total CaO in slag (kg/thm)=Base CaO +"? Ai *" "CaO%" /100
"where " A_i " is fluxes measured in kg/thm"
Total SiO_2 in slag (kg/thm)= (Total CaO in slag(kg/thm))/(Desired B2)
"where B2 = " "CaO" /("Si" O_2 )
where B2 is basicity of slag
As depicted at block 405, the flux determination module (206) determines difference in quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) required to achieve the desired slag chemistry, based on equations recited below:
?MgO=Desired MgO-MgO received from burden (excluding flux)
"if ?MgO >0,then the same is adjusted by supplying additional flux (which may be pyroxenite)"

?SiO_2=Desired SiO_2-SiO_2 received from burden (excluding flux)
"if ?" SiO_2 " >0,then the same is adjusted by supplying additional flux (quartz in this case)"

?CaO=Desired CaO-CaO received from burden (excluding flux)
"if ?CaO >0,then the same is adjusted by supplying additional flux (which may be limestone/dolomite)"
As depicted at block 406, the optimization module (207) predicts an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry. The optimization module (207) may employ the following steps for predicting said optimum quantity of fluxing material. Initially, the optimization module (207) calculates new MgO%. It may be determined that the calculated new MgO% is deviating from desired MgO% (can be either more than desired MgO or less than desired MgO). In case the calculated new MgO% is less than the desired MgO%, then additional pyroxenite may be supplied to the blast furnace. Additional pyroxenite may be calculated by employing equation as recited below:
Additional pyroxenite = (Desired MgO %-new MgO%) * (Base SV)/((MgO% in Pyro –Desired MgO%))
where, New SV = Base SV + Additional Pyroxenite to be supplied
As depicted at block 407, the optimization module (207) further determines CaO% and SiO2% in the slag and determines new B2 value based on the determined CaO% and SiO2%. It may be determined that the calculated new B2 value is deviating from desired B2 value (can be either more than desired B2 value or less than desired B2 value). Further, in case the calculated new B2 value is less than the desired B2 value, then additional quartz may be supplied to the blast furnace. Additional quartz may be calculated by employing equation as recited below:
Additional quartz to be supplied= (new SiO_2% from desired B2 value - calculated SiO_2%) * SV/((SiO_2% in Quartz – new SiO_2%))
where, New Quartz = Base + Additional Quartz

In an embodiment, the minimum slag rate determined by the slag rate determination module (205) may be defined as a sum of alumina (Al2O3), calcium oxide (CaO), magnesium oxide (MgO), silicon dioxide (SiO2) and operational losses (related to burdening process) associated with blast furnace.
The above method steps are further explained with the help of an example as follows. In an embodiment, the blast furnace may be burdened with 55 kg/thm of alumina (Al2O3), 115 kg/thm of calcium oxide (CaO), 35 kg/thm of magnesium oxide (MgO), and 110 kg/thm of silicon dioxide (SiO2). For such input of burden, the slag rate determined by the slag rate determination module (205) may be 305 kg/thm (without flux) and the alumina (Al2O3) content determined by the alumina determination module (204) may be 18.03 units. However, the system (200) may be configured to optimize the alumina (Al2O3) content to 18.5 units. Further, for optimizing the alumina (Al2O3) content to 18.5 units, the slag rate determination module (205) determines that the minimum slag rate required is 318 kg/thm (desired slag rate). To achieve said desired slag rate of 318 kg/thm and alumina (Al2O3) content of 18.5 units, the system (200) prompts or notifies the operator to burden the blast furnace with determined quantities of alumina (Al2O3), calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2), as determined by the modules (202-207) included in the system (200). The system (200) may also be configured to generate a signal (which may be optimum set points) of fluxes and raw material that is to be transferred from the control unit to a plant PLC (which may be configured to operate the blast furnace, and more specifically, the burdening process). The system (200) may be configured to determine quantity of burden to be supplied to the blast furnace based on a basicity value (B2) of slag, MgO% and Al2O3% in the slag.
In an embodiment, the system (200) may be configured to perform multiple iterations (at least three iterations) to achieve the optimum slag rate (which may be the desired slag rate), optimum slag chemistry (which may be desired slag chemistry), optimum B2 value (which may be desired B2 value) and the optimum alumina (Al2O3) content (which may be desired alumina (Al2O3) content).
In an embodiment of the disclosure, the control unit (201) may be a centralized control unit, or a dedicated control unit associated with the system (200). The control unit (201) may be implemented by any computing systems that is utilized to implement the features of the present disclosure. The control unit (201) may be comprised of a processing unit. The processing unit may comprise at least one data processor for executing program components for executing user- or system-generated requests. The processing unit may be a specialized processing unit such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. The processing unit may include a microprocessor, such as AMD Athlon, Duron or Opteron, ARM’s application, embedded or secure processors, IBM PowerPC, Intel’s Core, Itanium, Xeon, Celeron, or other line of processors, etc. The processing unit may be implemented using a mainframe, distributed processor, multi-core, parallel, grid, or other architectures. Some embodiments may utilize embedded technologies like application-specific integrated circuits (ASICs), digital signal processors (DSPs), Field Programmable Gate Arrays (FPGAs), and the like.

Further, in some embodiments, the processing unit may be disposed in communication with one or more memory devices (e.g., RAM, ROM etc.) via a storage interface. The storage interface may connect to memory devices including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as serial advanced technology attachment (SATA), integrated drive electronics (IDE), IEEE-1394, universal serial bus (USB), fiber channel, small computing system interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, redundant array of independent discs (RAID), solid-state memory devices, solid-state drives, and the like.

In an embodiment, the method (100) and the system (200) provide a standardized technique and framework for calculation of flux material quantities to be supplied to blast furnace. The method (100) and the system (200) provide a standard set of operating procedures to be followed for supplying optimal quantities of fluxing material required to achieve the desired slag chemistry. Further, the method (100) and the system (200) minimize operator dependency by eliminating operator role in calculation of fluxing material quantities to be supplied. The method (100) and the system (200) also eliminate possibility of the operator running in a leaner and safer slag chemistry with excess fluxing material supply, that results in consumption of excess fluxing material and higher slag rate. The method (100) and the system (200) reduce and/or eliminate supply of excess fluxing material to the blast furnace, by eliminating pre-existing non-compliance with target values of desired slag chemistry. The method (100) and the system (200) provide a tool configured to absorb wide variations in chemical composition of raw material supplied to blast furnace.

In an embodiment, the method (100) and the system (200) facilitate production of consistent quality of hot metal, by compensating gradual deterioration in quality of iron ore (i.e., increase in alumina and silica input) and coal (i.e., increase in ash input). The method (100) and system (200) are also configured to determine optimum fluxing material quantities to be supplied, based on real-time raw material chemistries, thereby reducing production cost of hot metal. Further, any variation in chemical composition of raw material is instantly identified, absorbed by the system (200), and is compensated in form of increased/decreased fluxing material quantities supplied to the blast furnace. Furthermore, the method (100) and system (200) consider latest available slag analysis values including chemical composition of flue dust loss and sludge waste in the blast furnace (which remained unaccounted for in the traditional burdening process), for determining optimum fluxing material quantities to be supplied to the blast furnace. The method (100) and system (200) optimize flux consumption and standardizes the process thereby efficiency.

EQUIVALENTS

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system (100) having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system (100) having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

REFERRAL NUMERICALS
Particulars Numerical
Method flow chart 100
Flow chart blocks 101-106
System for determining optimum flux 200
Control unit 201
Composition determination module 202
Average determination module 203
Alumina determination module 204
Slag rate determination module 205
Flux determination module 206
Optimization module 207
Memory unit 208
User interface unit 209
Process flow chart 300
Flow chart blocks 301-306

Claims:

1. A method (100) for determining optimum flux requirement for burdening process in a blast furnace, the method (100) comprising:
receiving (101), by a control unit (CU) (201), composition of raw materials to be supplied to the blast furnace and a desired slag chemistry for the composition of raw materials;
determining (102), by the control unit (201), representative average of chemistry values for each raw material to be supplied to the blast furnace, based on an exponential moving average (EMA) of a chemical composition of the raw materials supplied in a plurality of previous burdening processes of the blast furnace;
determining (103), by the control unit (201), alumina (Al2O3) load going into the blast furnace through the composition of the raw materials to be supplied into the blast furnace based on determined representative average of chemistry values for each raw material;
determining (104), by the control unit (201), minimum slag rate based on the desired slag chemistry and alumina load going into the blast furnace;
determining (105), by the control unit (201), minimum quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) based on the desired slag chemistry; and
predicting (106), by the control unit (201), an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry.

2. The method (100) as claimed in claim 1, wherein, the optimum quantity of fluxing material is determined for at least one of limestone, dolomite, pyroxenite and quartzite in terms of mass percentage.

3. The method (100) as claimed in claim 1, comprises comparing, by the control unit (201), produced slag chemistry with the desired slag chemistry, to indicate variation in composition of the slag based on the predicted optimum quantity of fluxing material supplied to the burdening process.

4. The method (100) as claimed in claim 1, comprises adjusting, by the control unit (201), the predicted optimum quantity of fluxing material, to minimize variation between the produced slag chemistry and the desired slag chemistry, in a subsequent burdening process of the blast furnace.

5. The method (100) as claimed in claim 1, wherein the desired slag chemistry received by the control unit (201) is based on parameters including at least one of the minimum slag rate, basicity of the slag, mass percentage of at least one of Al2O3, CaO, MgO and SiO2, required in unit quantity of the slag.

6. The method (100) as claimed in claim 1, wherein the raw material includes fuel material, iron-bearing material, and fluxing material for the burdening process.

7. The method (100) as claimed in claim 5, wherein the fuel material includes at least one of coke, pulverized coal, and coal tar.

8. The method (100) as claimed in claim 5, wherein the iron-bearing material includes at least one of sinter, pellet, iron ore and briquettes.

9. The method (100) as claimed in claim 1, wherein the quantity of mass percentage of CaO to be supplied to the blast furnace is determined based on CaO obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of CaO required for the desired slag chemistry.

10. The method (100) as claimed in claim 1, wherein the quantity of mass percentage of MgO to be supplied to the blast furnace is determined based on MgO obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of MgO required for the desired slag chemistry.

11. The method (100) as claimed in claim 1, wherein the quantity of mass percentage of SiO2 to be supplied to the blast furnace is determined based on SiO2 obtained from all raw materials to be supplied to the blast furnace and the minimum quantity of mass percentage of SiO2 required for the desired slag chemistry.

12. A system (200) for determining optimum flux requirement for burdening process in a blast furnace, the system (200) comprising:
a control unit (CU) (201) configured to,
receive composition of raw materials to be supplied to the blast furnace and a desired slag chemistry for the composition of raw materials;
determine representative average of chemistry values for each raw material to be supplied to the blast furnace, based on an exponential moving average (EMA) of a chemical composition of raw materials supplied in a plurality of previous burdening processes of the blast furnace;
determine alumina (Al2O3) load going into the blast furnace through the composition of raw materials to be supplied into the blast furnace based on determined representative average of chemistry values for each raw material;
determine minimum slag rate based on the desired slag chemistry and alumina load going into the blast furnace;
determine minimum quantity of mass percentage of calcium oxide (CaO), magnesium oxide (MgO) and silicon dioxide (SiO2) based on the desired slag chemistry; and
predict an optimum quantity of fluxing material for the burdening process, to obtain the determined minimum slag rate and the desired slag chemistry.

13. The system (200) as claimed in claim 12, wherein the control unit (201) is configured to compare produced slag chemistry with the desired slag chemistry, to indicate variation in composition of the slag based on the predicted optimum quantity of fluxing material supplied to the burdening process.

14. The system (200) as claimed in claim 12, wherein the control unit (201) is configured to adjust the predicted optimum quantity of fluxing material, to minimize variation between the produced slag chemistry and the desired slag chemistry, in a subsequent burdening process of the blast furnace.

15. The system (200) as claimed in claim 12, wherein the desired slag chemistry received by the control unit (201) is based on parameters including at least one of the minimum slag rate, basicity of the slag, mass percentage of at least one of Al2O3, CaO, MgO and SiO2, required in unit quantity of the slag.

16. The system (200) as claimed in claim 12, comprises a memory unit (208) for storing the exponential moving average (EMA) of the chemical composition of raw materials supplied in the plurality of previous burdening processes of the blast furnace.

17. The system (200) as claimed in claim 12, comprises a user interface unit (209) configured to enable a user to input the composition of raw materials to be supplied to the blast furnace and to input the desired slag chemistry for the composition of raw materials.

18. A blast furnace comprising a system (200) as claimed in claim 12 for determining optimum flux requirement for burdening process.