WO2023131858A1

WO2023131858A1 - Method and system for determining and controlling thermal level of a blast furnace

Info

Publication number: WO2023131858A1
Application number: PCT/IB2022/062871
Authority: WO
Inventors: Hazra Sujan; Bansi Abhale PRAKASH; Agrawal ASHISH; Kumar Singh BASANT; Ranjan Tripathi VINEET; Pal PADMA; Nag Samik; Singh Uttam
Original assignee: Tata Steel Limited
Priority date: 2022-01-04
Filing date: 2022-12-29
Publication date: 2023-07-13

Abstract

Disclosed herein is a method and system for determining and controlling thermal level of a blast furnace. In an embodiment, the method comprises acquiring real-time values of a plurality of operational parameters associated with the blast furnace using a plurality of devices associated with the blast furnace. Subsequently, a plurality of chemical properties related to the blast furnace are determined based on predetermined chemical analyses. Further, a lead thermal indicator of the blast furnace is estimated by analysing the real-time values of the plurality of operational parameters and the plurality of chemical properties. Thereafter, the optimal values of the plurality of operational parameters are determined for controlling the thermal level of the blast furnace within a predefined temperature range. In an embodiment, the method of present disclosure helps in adjusting or controlling the operating parameters of the blast furnace, thereby maintaining the thermal stability of the blast furnace.

Description

METHOD AND SYSTEM FOR DETERMINING AND CONTROLLING

THERMAL LEVEL OF A BLAST FURNACE

TECHNICAL FIELD

The present subject matter is, in general, related to estimating thermal stability of a blast furnace and more particularly, but not exclusively, to a method and a system for determining and controlling the thermal level of the blast furnace.

BACKGROUND

In steel manufacturing industrial plants, the main focus is on increasing productivity of the blast furnace while simultaneously reducing tire cost of a hot metal. Also, the process of controlling thermal level of the blast furnace is considered to be the most essential part for blast furnace operation, as the lower thermal level may lead to unstable furnace operation. This, in turn, hampers the performance of the blast furnace in terms of its productivity. Further, the lower thermal level makes tapping of hot metal and slag more difficult. If the lower r thermal level of the blast furnace goes unchecked, in extreme conditions, this may lead to chilled or semi-chilled conditions in the hearth of the blast furnace and causes force shutdown of the furnace, which is significantly a financial loss.

On the other hand, the higher thermal level in the blast furnace may lead to higher fuel consumption. Consequently, it reduces permeability and increases the heat loss, thereby hindering gas and liquid flows in the lower part (hearth) of the blast furnace. So, maintaining a right thermal level is essential for stable and efficient operation of the blast furnace.

Conventionally, the thermal state of the blast furnace was predicted manually by blast furnace operators based on their experience of stave temperatures and heat losses in lower zone, hot metal temperature, and silicon level during tapping. However, the manual predictions or judgments of the furnace operators may not be accurate, and this leads to inefficient operation of the blast furnace.

Other existing approaches include use of blast furnace decision support systems for controlling thermal levels using a combination of knowledge from existing critical procedures and knowledge acquired from domain experts. However, these approaches use rule-based guidance system based on a particular reference state of the blast furnace. So, if the present operating regime is different from the reference state, the rule-based guidance system may not be valid for the new regime at all.

Though the conventional methods use various approaches to judge the thermal state of the blast furnace, no effort has been made to simplify the analysis to find a single parameter, which indicates the thermal state of the blast furnace and in turn helps in controlling the thermal state of the blast furnace.

The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled m the art.

SUMMARY

Disclosed herein is a method for determining and controlling thermal level of a blast furnace. The method comprises acquiring, by a controller, real-time values of a plurality of operational parameters associated with the blast furnace using a plurality of devices associated with the blast furnace. Further, the method comprises determining a plurality of chemical properties related to the blast furnace based on predetermined chemical analyses and estimating a lead thermal indicator of the blast furnace by analyzing the real-time values of the plurality of operational parameters and the plurality of chemical properties. Thereafter, the method comprises determining optimal values of tlie plurality of operational parameters for controlling the thermal level of the blast furnace within a predefined temperature range.

Further, the present disclosure relates to a control system for determining and controlling thermal level of a blast furnace. The control system comprises a controller and a memory'. The memory is communicatively coupled to the controller and stores processor-executable instructions, which on execution, cause the controller to acquire real-time values of a plurality of operational parameters associated with the blast furnace using a plurality of devices associated with the blast furnace. Further, the instructions cause the controller to determine a plurality of chemical properties related to the blast furnace based on predetermined chemical analyses and estimate a lead thermal indicator of the blast furnace by analyzing the real-time values of the plurality of operational parameters and the plurality of chemical properties. Thereafter, the instructions cause the controller to determine optimal values of tlie plurality of operational parameters for controlling the thermal level of the blast furnace within a predefined temperature range.

In an embodiment of the present disclosure, the plurality of operational parameters comprises at least one of flow rates of at least one of wind, oxygen, steam, top gas, cooling water, injected coal conveying medium, blast temperature comprising wind, oxygen and steam before entering tuyere, inlet and outlet temperature of cooling water required for blast furnace cooling, hot metal temperature leaving blast furnace during cast and temperature of injected fuels, concentration of Carbon Monoxide (CO), Carbon Dioxide (CO2) Hydrogen (H₂) in top gas of tlie blast furnace, weights of burden material comprising at least one of coke, iron bearing materials, and fluxes and moisture levels of the burden material comprising at least one of coke and iron bearing materials.

Tn a further embodiment of the present disclosure, the plurality of devices associated with the blast furnace comprises one or more flow meters, temperature sensors, gas analysers, weighing devices and moisture analysers.

In a further embodiment of the present disclosure, the plurality of chemical properties comprises at least one of ultimate and proximate analyses of fuels comprising at least one of coke and coal, chemical composition of iron bearing materials comprising at least one of flue dust and fluxes and weight percentage of total Iron (Fe) and Ferrous Oxide (FeO), chemical composition of hot metal and slag, and calorific value of injectant fuels comprising at least one of coal, tar, natural gas and other fuels.

Tn a further embodiment of the present disclosure, the method comprises performing one or more pre-processing operations on the real-time values of the plurality of operational parameters and the plurality of chemical properties before estimating the lead indicator of the blast furnace.

Tn a further embodiment of the present disclosure, the one or more pre-processing operations comprises a data cleansing operation for removing negative values, values outside min-max range and empty values, an averaging operation for averaging of periodic data comprising at least one of temperature, flow rates and gas composition, a summing operation for summing burden weights, and regularizing infrequent data based on last available data, until next measured data is available. In a further embodiment of the present disclosure, the process of estimating the lead indicator comprises dividing the blast furnace virtually into a plurality of zones based on difference in temperature at different region of the blast furnace, wherein the plurality of zones comprises at least one of a lower zone and a thermal reserve zone. The process of estimating the lead indicator further comprises determining value of a heat balance factor corresponding to the lower zone based on analysis of the real-time values of the plurality of operational parameters and the plurality of chemical properties and estimating the lead thermal indicator by subtracting values of one or more heat loss parameters from the value of the heat balance factor.

In a further embodiment of the present disclosure, the one or more heat loss parameters comprises at least one of coal dissociation heat, heat loss to wall of the lower zone and limestone decomposition heat.

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

Tire accompanying drawings, which are incorporated in and constitute apart of this disclosure, illustrate exemplary embodiments and, together with the description, explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and regarding the accompanying figures, in which:

FIG. 1 shows a detailed block diagram of a control system in accordance with some embodiments of the present disclosure.

FIG. 2A shows a schematic representation of a RIST diagram in accordance with some exemplary embodiments of the present disclosure. FIG. 2B illustrates a flowchart illustrating a method for estimating thermal indicator of the blast furnace in accordance with some embodiments of the present disclosure.

FIG. 3 shows a flowchart illustrating a method for determining and controlling thermal level of a blast furnace in accordance with some embodiments of the present disclosure.

FIG. 4 show's a graphical representation of variation in thermal level indicator based on operating conditions of the blast furnace in accordance with some embodiments of the present disclosure.

FIG. 5 illustrates an exemplary' user interface of an automation unit of the control system in accordance with some embodiments of the present disclosure.

FIGS. 6 and 7 illustrate experimental results showing a comparison between the thermal indicator and hot metal temperature in accordance with some embodiments of the present disclosure.

FIG. 8 indicates reduction in standard deviation of the hot metal temperature with the implementation of the present disclosure.

FIG. 9 illustrates a block diagram of an exemplary' computer system for implementing embodiments consistent with the present disclosure.

It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual view's of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether such computer or processor is explicitly shown.

DETAILED DESCRIPTION

In the present document, the word “exemplary'” is used herein to mean “serving as an example, instance, or illustration”. Any embodiment or implementation of the present subject matter described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below⁷. It should be understood, however that it is not intended to limit the disclosure to the specific 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”, “includes”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device, or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises ... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

Tn the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

FIG. 1 show's a detailed block diagram of a control system WO in accordance with some embodiments of the present disclosure.

In some implementations, the control system 100 may comprise, without limiting to, a controller 101, a memory 103, a data acquisition model 107, a first computation model 109, a second computation model 111, and an automation unit 115. The controller 101 may be configured to perform one or more functions of the control system 100 for determining and controlling thermal level of a blast furnace using external data 105 collected by the data acquisition model 107 or the data stored on a data server 119. Further, the memory 103 is communicatively coupled to the controller 101 and stores data and instructions. In an embodiment, the external data 107 includes, but not limited to, a plurality of operational parameters associated with the blast furnace and a plurality of chemical properties related to the blast furnace. Tn an embodiment, the plurality of operational parameters associated with the blast furnace may include, without limitation, flow rates of at least one of wind, oxygen, steam, top gas, cooling water, injected coal conveying medium, and gaseous or liquid fuels.

The plurality of operational parameters may further include blast temperature comprising wind, oxygen and steam before entering tuyere, inlet and outle t temperature of cooling water required for the blast furnace cooling, hot metal temperature leaving blast furnace during case and temperature of injected fuels. Further, the plurality of operational parameters may also include concentration of Carbon Monoxide (CO), Carbon Dioxide (CO₂) and Hydrogen ( H₂) in top gas of the blast furnace, and -weights of burden materials comprising at least one of coke, iron bearing materials and fluxes. Additionally, the plurality of operational parameters may include moisture levels of the burden materials comprising at least one of coke and iron bearing materials and the like. In an embodiment, the controller 101 may acquire real-time values of the plurality of operational parameters associated with the blast furnace using a plurality of devices 117 (not shown) associated with the blast furnace.

In an embodiment, the plurality of devices 117 associated with the blast furnace may include, but not limited to, one or more flow meters, temperature sensors, gas analyzers, weighing devices and moisture analyzers.

In an embodiment, the plurality of chemical properties related to the blast furnace may include, without limiting to, ultimate and proximate analyses of fuels comprising at least one of coke and coal, and chem ical composition of iron bearing materials comprising at least one of flue dust and fluxes and weight percentage of total Iron (Fe) and Ferrous Oxide (FeO). Further, the data may also include chemical composition of hot metal, slag, and calorific value ofinjectant fuels comprising at least one of coal, tar, natural gas, and other fuels. The controller 101 may determine the plurality of chemical properties based on predetermined chemical analyses performed by expert professionals.

In an embodiment, the first computation model 109 may be configured to receive real-time values of the plurality of operational parameters and the plurality of chemical properties from the data acquisition model 107. Further, the first computation model 109 may perform one or more pre-processing operations on the real-time values of the plurality of operational parameters and the plurality of chemical properties before estimating the lead thermal indicator of the blast furnace. As an example, the one or more pre-processing operations may include, without limiting to, a data cleansing operation, an averaging operation, a summing operation, and data regularization.

In an embodiment, the data cleansing operation may include removing negative values, values outside min-max range and empty values. In an embodiment, the averaging operation may include averaging of periodic data comprising at least one of temperature, flow rates and gas composition. In an embodiment, the summing operation may include summation of burden weights. In an embodiment, the regularization operation may include regularizing infrequent data based on at least available data, until next measured data is available.

In an embodiment, the data pre-processing operations are performed for a specific time period, and the processed data are passed on to the second computation model 111 for further processing.

In an embodiment, the second computation model 111 may be configured to estimate a thermal indicator or a lead thermal indicator of the blast furnace. In an embodiment, the thermal indicator may be a single point or a single parameter which indicates the thermal state or thermal stability of the blast furnace. The second computation model 111 may divide the blast furnace virtually into a plurality of zones based on difference in temperature at different regions of the blast furnace. As an example, the plurality of zones may comprise an upper zone and a thermal reserve zone.

In an embodiment, the second computation model 111 may determine a value of a heat balance factor corresponding to the lower zone based on analysis of the real-time values of the plurality of operational parameters and the plurality of chemical properties. Further, the second computation model 111 may estimate the lead thermal indicator by subtracting values of one or more heat loss parameters from the value of the heat balance factor. Tire one or more heat loss parameters comprise, without limitation, at least one of coal dissociation heat, heat loss to wall of the lower zone and limestone decomposition heat. hr an embodiment, the automation unit 115 may be configured for generating and presenting user-readable analysis related to thermal level of the blast furnace by processing the thermal level indicator determined by the second computation model. That is, the automation unit 115 post-processes the outcome of the second computation model 111 generates various graphical and tabular interfaces and presents them on a user interface 113. Further, an operator of the blast furnace may continuously monitor the results presented on the user interface to take actions required to maintain the thermal stability of the blast furnace.

FIG. 2A show^s a schematic representation of a RIST diagram in accordance with some embodiments ofthe present disclosure. In an embodiment, the second computation module 107 estimates the thermal indicator of the blast furnace based on the RIST concept. The RIST diagram is a representation of elemental balances that are represented by an operating line drawn on (O+H2)/(C+H₂) and (O+H2)/Fe as ‘X’ and ‘Y’ axis, respectively. FIG. 2A shows an exemplary representation ofthe RIST diagram in accordance with embodiments ofthe present disclosure.

FIG. 2B shows a flowchart illustrating a method for estimating thermal indicator of the blast furnace in accordance with some exemplary embodiments.

At block 202, the method 200 includes, evaluating an ‘X’ coordinate of point ‘A’ (refer FIG. 2A) based on measured top gas composition consisting of volume percentages of CO, CO2 and H₂ in dry basis. In an embodiment, the ‘X’ coordinate of the point ‘A’ (XA) may be determined using equation (1) shown below:

In equation (1), percentage of H?.O in wet top gas is to be obtained from overall hydrogen balance and then measured dry top gas analysis needs to be converted to wet basis using nitrogen balance of the blast furnace.

Further, the method 200 includes, evaluating a ‘Y’ coordinate of point ‘A’ based on weighted average of total iron (Fe) and iron oxide (FeO) content of all iron bearing burden material. The iron bearing burden material may include, but not limited to, pellet, sinter, lump, ore, scrap, briquettes, and fluxes, which may comprise at least one of dolomite, limestone, quartzite, dunnite and the like. In an embodiment, the 'Y’ coordinate of point ‘A’ may be determined using equation (2.) shown below:

Here, the measured weights may be converted to dry basis based on moisture content for evaluation of YA.

At block 204. the method 200 includes, evaluating ‘Y’ coordinate of point ‘D’ based on the carbon balancing, as shown in the equation (3) below:

Carbon in top gas ^:= Carbon burnt in raceway

+ Carbon released as Loss of Ignition (LOI)

+ Carbon consumed in direct reduction of FeO

+ Carbon consumed in direct reduction of minor oxides

- Carbon in hot metal

- Carbon in flue dust ... (3)

Further, the carbon consumed in direct reduction of FeO is obtained by rearranging the equation (3) as shown above:

Carbon consumed in direct reduction of FeO = Carbon in top gas

--- Carbon burnt in raceway

- Carbon released as LOI

- Carbon consumed in reduction of minor oxides

+ Carbon in hot metal

+ Carbon in flue dust ... (4)

The variables in equation (4) are measured m per mole of Fe basis. From this ‘Y’ coordinate of point ‘D’ carbon consumption is determined from stoichiometry' of direct reduction reaction, as shown in equation (5) below:

FeO + C - Fe + CO ... (5)

In an embodiment, the ‘X’ coordinate of point ‘D’ is taken as 1 by definition of direct reduction ofFeO. At block 206, the method 200 includes, evaluating the ‘Y’ coordinate of point ‘B’ based on extrapolation of line AD at X==0 (shown in FIG. 2A).

At block 208, tire method 200 includes evaluating the ‘Y’ coordinate of point ‘U' based on oxygen released by the minor oxides reduction and oxygen and hydrogen supplied by the coke and injectant, as shown in equation (7) below:

Here, the ‘X’ coordinate of point ‘LT is taken as 0 by definition.

At block 210, the method 200 includes evaluating ‘Y’ coordinate of point ‘V’ (as shown in FIG. 2) based on heat balance of lower zone of the blast furnace at steady state. The lower zone is defined from bottom till end of thermal reserve zone of the blast furnace.

At block 212, the method 200 includes evaluating heat demand and other then heat of solution loss reaction. The heat demand and heat of solution loss reaction is shown in equations (8)-( 12) below:

Heat in + Heat generated = Heat out + Heat consumed/lost . . . (8)

Heat in = Heat of burden at thermal reserve zone temperature + Head of blast at tuyere level ... (9)

Heat out = Heat of hot metal and slag at iron notch

+ Heat of gas at thermal reserve zone temperature ... (10)

Heat generated = Heat of combustion at raceway ... (11)

Heat consumed = Heat of solution loss reaction

+ Heat of melting iron and slag

+ Heat requirements for reduction of minor oxides and their dissolution in hot metal

+ Heat requirements of various endothermic reactions involving H2

+ Heat Loss to wall + Heat of calcium carbonate decomposition + heat of injectant dissociation ... (12)

Tn an embodiment, by taking thermal reserve zone temperature as reference temperature, the heat in by burden and heat out by gas at thermal reserve zone becomes zero. The remaining terms in equation (9)-( 12) may be arranged in the following form:

Where:

H = Heat of solution loss reaction Heat of melting iron and slag

+ Heat requirements of various endothermic reactions involving H2

+ Heat Loss to wall

+ Heat of calcium carbonate decomposition

+ heat of injectant dissociation . . . (14)

Now, dividing both sides of equation (13) by the factor ‘q solution loss’ following equations are obtained:

Further, the equation (15) may be re-arranged in the following form:

From similar Triangles APBU and APDV m FIG. 2A,

as,

From equation (15) and (17):

The parameters in equation (18), such as, H_blast and H_solution loss may be estimated from blast condition such as blast rate, humidity, oxygen enrichment, blast temperature and the like.

At block 214, the method 200 includes evaluating coal dissociation and limestone decomposition heat. That is, the equation (18) determines the value of ‘H’ and thereafter subtracts the coal dissociation heat, heat loss to wall of lower zone and limestone decomposition heat and estimates the thermal indicator, as shown in block 216. That is, it represents the melting and superheating of metal and slag and heat requirement of reduction of minor oxides and their dissolution to hot metal. Thereby it represents the thermal state of the blast furnace.

In an embodiment, the trend for a specific period of time represents the change of thermal condition of the blast furnace. For example, the downward trend indicates thermal dip of the blast furnace and vice versa. The examples illustrated in Figures 4-7 demonstrate the application of the method of present disclosure to the blast furnace. However, the applicability and scope of the present disclosure shall not be limited to these examples.

FIG. 3 show's a. flowchart illustrating a. method for determining and controlling thermal level of a blast furnace in accordance with some embodiments of the present disclosure.

As illustrated in FIG. 3, the method 300 may include one or more blocks illustrating a method for determ ining and controlling thermal level of a blast furnace using a control system 100 illustrated in FIG. 1 . The method 300 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform specific functions or implement specific abstract data types.

The order in which the method 300 is described, is not intended to be construed as a. limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof.

At block 302, the method 300 includes acquiring, by the controller 101 , real-time values of a plurality of operational parameters associated with the blast furnace using a plurality of devices 117 associated with the blast furnace. In an embodiment, the plurality of operational parameters comprise, without limiting to, at least one of flow rates of at least one of wind, oxygen, steam, top gas, cooling water, injected coal conveying medium and gaseous or liquid fuels, blast temperature comprising wind, oxygen and steam before entering tuyere, inlet and outlet temperature of cooling water required for blast furnace cooling, hot metal temperature leaving blast furnace during cast and temperature of injected fuels, concentration of CO, CO₂, and H₂ in top gas of the blast furnace, weights of burden materials comprising at least one of coke, iron bearing materials and fluxes, and moisture levels of the burden materials comprising at least one of coke and iron bearing materials. Further, the plurality of devices 117 associated with the blast furnace may include, but not limited to, one or more flow meters, temperature sensors, gas analysers, weighting devices, and moisture analysers.

At block 304, the method 300 includes determining, by the controller 101, a plurality of chemical properties related to the blast furnace based on predetermined chemical analyses. In an embodiment, tire plurality of chemical properties comprises at least one of ultimate and proximate analyses of fuels comprising at least one of coke and coal, chemical composition of iron bearing materials comprising at least one of flue dust and fluxes and weight percentage of total Iron (Fe) and Ferrous Oxide (FeO), chemical composition of hot metal and slag, calorific value of inj ectant fuels comprising at least one of coal, tar, natural gas and other fuels.

In an embodiment, the method also includes performing one or more pre-processing operations on the real-time values of the plurality of operational parameters and the plurality of chemical properties before estimating the lead thermal indicator of the blast furnace. In an embodiment, the one or more pre-processing operations comprises, without limiting to, a data cleansing operation for removing negative values, values outside min-max range and empty' values, an averaging operation for averaging of periodic data comprising at least one of temperature, flow rates and gas composition, a summing operation for summing of burden weights, and regularizing infrequent data based on last available data, until next measured data is available.

At block 306. the method 300 includes estimating, by the controller 101, a thermal indicator or a lead thermal indicator of the blast furnace by analysing the real-time values of the plurality of operational parameters and the plurality of chemical properties. In an embodiment, the process of estimating the lead thermal indicator comprises di viding the blast furnace virtually into a plurality of zones based on difference in temperature at different region of the blast furnace, such that the plurality of zones comprises at least one of a upper zone, and a thermal reserve zone. Further, the method includes determining value of a heat balance factor corresponding to the lower zone based on analysis of the real-time values of the plurality of operational parameters and the plurality of chemical properties. Thereafter, the lead thermal indicator is estimated by subtracting values of one or more heat loss parameters from the value of the heat balance factor. In an embodiment, the one or more heat loss parameters may include, but not limited to, coal dissociation heat, heat loss to wall of the lower zone and limestone decomposition heat.

At block 308, the method 300 includes determining, by the controller 101, optimal values of the plurality of operational parameters for controlling the thermal level of the blast furnace within a predefined temperature range.

FIG. 4 shows a graphical representation of variation in thermal level indicator based on operating conditions of the blast furnace in accordance with some embodiments of the present disclosure.

In an embodiment, initially, the burden containing sinter (40-50 wt. %) and rest of sized lump ore are charged onto the top of the blast furnace. Further, fluxes such as limestone (1-20 kg/ton of hot metal), dolomite (0-30 kg/ton of hot metal), quartz (0-20kg/ton of hot metal), pyroxenite (0-30 kg/ton of hot metal) are added along with iron bearing burden. The overall content of the total iron (Fe) and iron oxide (FeO) may be 58-64 wt. % and 4-6 wt. % respectively. The coke charged 280-330 kg/ton of hot metal (dry basis) and coal injection 180-220 kg/ton of hot metal is used as fuel. The burden and fuel composition are shown in table, 1 below:

Table 1 : Burden and Fuel compositions

Further, the ultimate analysis of the coke and coal may be determined as shown in Table. 2

Table 2: Ultimate analysis of coke and coal

Furthermore, the coke may be charged in alternate layers within iron bearing materials and fluxes, whereas the coal is injected through tuyeres in pulverized form. Subsequently, the wet blast, including oxygen enrichment in the range of 2 to 6 % (dry blast containing oxygen and nitrogen), and steam in the range of 10~54 g/Nm³rm of dry blast is blown in the range of 942- 1124 Nm7ton of hot metal through tuyeres maintaining blast temperature at 1130-1162 ^GC. Tire exit top gas consists of carbon monoxide (CO) in the range of 23.2 -26.4%, carbon dioxide (CO₂) in the range of 22.7-25.8 % Hydrogen (H₂) in the range of 4.2-5.3 and rest of the content mainly including Nitrogen. In an embodiment, the heat loss in the lower zone of the blast furnace is 66200-97300 MJ/ton of hot metal. The Blast conditions, top gas composition and heat loss are summarized in Table 3 below:

Table 3: Blast conditions, top gas composition and heat loss

Also, the chemical analysis of the hot metal is summarized in Table 4 shown below':

Table 4: Hot metal analysis

In an embodiment, the hot metal temperature is in the range of 1489-1515°C, and it is one of tlie measurements to judge the thermal condition in the blast furnace. The data mentioned above are the average to daily basis.

Further, FIG. 4 summarizes the values of thermal level indicators estimated for twenty days based on above mentioned operating condition. The thermal level indicator correlates with hot metal temperature, which is a measured parameter indicating thermal level, having coefficient of determination (R-square) 0.74.

FIG. 5 illustrates an exemplary user interface of an automation unit of the control system in accordance with some embodiments of the present disclosure.

In an embodiment, the left graph in FIG. 5 shows the trends of the thermal indicator and hot metal temperature over a specific period of time. The data mentioned in the lower part of the FIG. 5 displays the input and output of the computation modules. The right graph of FIG. 5 shows RIST diagram using computation module 2 for a specific time step.

In an embodiment, the hot metal temperature may be considered to be one of the key indicators of thermal status of the blast furnace, adjustment of process parameters like fuel rate, blowing parameters, burden change is done based on measurement of hot metal temperature. However, response in hot metal temperature takes time to get the effect of adjusted process parameters. For example, it may take about 3-4 hours and 6-8 hours to the see the movement in the hot metal temperature in case of pulverized coal and coke adjustments, respectively. Moreover, hot metal temperature is discontinuous measurement, and hence, at most 2-3 readings are available when tapping of hot metal and slag is done. Therefore, as already highlighted in the earlier sections of the disclosure, there is a need of thermal indicator, which can provide prior information as well as continuous reading of thermal level of the blast furnace.

FIG. 6 illustrates an implementation of the present invention in accordance with some embodiments of the present disclosure. In FIG. 6, the ‘x-axis’ denotes the time for a specific period and ‘y-axis' denotes thermal level indicator and hot metal temperature. In FIG. 6, it may be observed that thermal level indicator (in blue color) predicts the rise or dip of hot metal temperature (in green color) a priori. Further, in the implementation, there are eight instances, where thermal indicator (in blue color) forecasts the rise or dip of hot metal temperature. The instances are marked by arrows in FIG. 6. For instance, the dotted arrows indicate change of thermal indicator, whereas the solid arrow indicates the change in hot metal temperature. Additionally, the numbers from 1 to 8 are assigned to match trends of thermal indicator and hot metal temperature. Further, in FIG. 6, it may be also observed that the thermal indicator acts as a lead indicator, as it predicts thermal status of the blast furnace 70-100 minutes prior to the hot metal temperature.

Consequently, with the help of thermal indicator, the method of present disclosure may be used to control or adjust the process parameters in such a way that the thermal level of the blast furnace is maintained within a desired limit. Therefore, the changes in process parameters are captured in the computation of current scheme and computed the thermal indicator by the changes of said parameters. As a result, the method of present disclosure may be also used as a feedback control tool, that guides the blast furnace operators to take necessary' actions for consistent and smooth ran of the blast furnace.

FIG. 7 illustrates change of coal rate in the blast furnace based on the thermal indicator, in accordance with some embodiments of the present disclosure.

In an embodiment, one of the most important levers to control the thermal stability is the fuel rates. Assuming, coke, and coal are tire fuels used, FIG. 7 depicts tire thermal indicator (in blue color) and hot metal temperature (in green color) for a specific period of time. A bottom figure of FIG. 7 shows coke (blue color) and coal rate (red color) for kg/ton of hot metal for same period. hr the top figure, the increase of thermal indicator (levelled as WU STAR, MJ/THM, in blue color) is observed and indicated by arrow 1. During this period, no change of fuel rate, for both coke and coal, is observed as shown in the botom figure of FIG. 7. Further, increase in the thermal indicator, mentioned by arrow 2, leads to guide tire operator to reduce the coal rate from 182, to 171 kg/HTM, i.e., a reduction of 11 kg/THM in steps while keeping the coke rate constant. The resulted decrease in the hot metal temperature is from 1530° C to a level of 1500- 1505° C, which is a desired operating temperature band. In other words, this case study demonstrates that the thermal indicator can be used as an operating tool to adjust the fuel rate prior to the hot metal temperature.

Further, a similar instance can be observed at a later period, marked by the arrows 4 and 5. Due to rise in the thermal indicator, marked as 4 in the top figure of FIG. 7, the coal rate is cut down from 176 to 164 kg/THM in four steps. This leads to decrease m the thermal indictor (levelled as WU__STAR, MJ/THM, in blue color). Subsequently, the hot metal temperature is decreased to desired level, marked by arrow 5. Due to cut down in the coal rate by 12 kg/THM, the hot metal temperature is dropped from higher value (1539° Cj to normal operating band (i.e., 1507- 1499° C).

Thus, the successfill implementation of the present di sclosure may be confirmed by the case study, mentioned above. That is, the present disclosure captures deviation of thermal stability from normal operating band and thereby guides the blast furnace operator to adjust operating parameters to restort t he thermal stability of the blast furnace. All tire actions may be taken prior to the indication of dip or rise in the hot metal temperature and therefor operator’s actions to adjust the operating parameters can be taken earlier due to continuous forecasting of the thermal status.

In an embodiment, the standard deviation of the hot metal temperature may be reduced from 18° C to 14° C. Specifically, as shown in FIG. 8, a first period may be considered as four months before implementation of the model and the second period may be considered as the period after implementation of the method of present disclosure. The reduction of the standard deviation of the hot metal temperature is by 4° C, which is in agreement with less disturbance and deviation from the desired operation of the blast furnace. the desired operation refers to the optimal operating with respect to the operating parameters, such as fuel consumption, productivity, and the like. That is, the method of present disclosure greatly enhances the operator’s confidence to run the blast furnace smoothly, by controlling the process parameters based on the computed thermal indicator.

Exemplary Computer System

FIG. 9 illustrates a block diagram of an exemplary computer system 900 for implementing embodiments consistent with the present disclosure. In an embodiment, the computer system 900 may be the control system 100 illustrated in FIG. 1, which may be used for determining and controlling thermal level of a blast furnace. The computer system 900 may include a Central Processing Unit (“CPU” or “processor”) 902. The processor 902 may comprise at least one data processor for executing program components for executing user-or-system generated processes. A user may include a technician, or an operator of the blast furnace or any system/sub-system being operated parallelly to the computer system 900. The processor 902 may include specialized processing units such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc.

The processor 902 may be disposed in communication with one or more Input/Output (I/O) devices (911 and 912) via I/O interface 901. The I/O interface 901 may employ communication protocols/methods such as, without limitation, audio, analogue, digital, stereo, IEEE®-! 394, serial bus, Universal Serial Bus (USB), infrared, PS/2, BNC, coaxial, component, composite, Digital Visual Interface (DVI), high-definition multimedia interface (HDMI), Radio Frequency (RF) antennas, S-Video, Video Graphics Array (VGA), IEEE® 8O2.n /b/g/n/x, Bluetooth, cellular (e.g., Code-Division Multiple Access (CDMA), High-Speed Packet Access (HSPA+), Global System For Mobile Communications (GSM), Long-Term Evolution (LTE) or the like), etc. Using the I/O interface 901, the computer system 900 may communicate with one or more I/O devices 911 and 912.

In some embodiments, tire processor 902 may be disposed in communication with a communication network 909 via network interface 903. The network interface 903 may communicate with the communication network 909. The network interface 903 may employ connection protocols including, without limitation, direct connect, Ethernet (e.g., twisted pair 10/100/1000 Base T), Transmission Control Protocol/Intemet Protocol (TCP/IP), token ring IEEE® 802. 1 la/b/g/n/x, etc. Using the network interface 903 and the communication network 909, the computer system 900 may connect with a plurality of devices 117 for receiving real- time values of a plurality of operational parameters associated with the blast furnace. Further, the communication network 909 may be used for interfacing the computer system 900 with a data server 119 which stores a plurality of chemical properties related to the blast furnace based on predetermined chemical analyses and provides analysis results for determining and controlling the thermal level of a blast furnace.

In an implementation, the communication network 909 may be implemented as one of the several types of networks, such as intranet or Local Area Network (LAN) and such within the organization. The communication network 909 may either be a dedicated network or a shared network, which represents an association of several types of networks that use a variety of protocols, for example, Hypertext Transfer Protocol (HTTP), Transmission Control Protocol /Internet Protocol (TCP/IP), Wireless Application Protocol (WAP), etc., to communicate with each other. Further, the communication network 909 may include a variety of network devices, including routers, bridges, servers, computing devices, storage devices, etc.

In some embodiments, the processor 902 may be disposed in communication with a memory 905 (e.g., RAM 913, ROM 914, etc. as shown in FIG. 9) via a storage interface 904. The storage interface 904 may connect to memory 905 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 Computer Systems 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 m em ory devices, solid-state drives, etc.

Tire memory 905 may store a collection of program or database components, including, without limitation, user/application interface 906, an operating system 907, a web brov/ser 908, and the like. In some embodiments, computer system 900 may store user/application data 906, such as the data, variables, records, etc. as described in this invention. Such databases may be implemented as fault-tol erant, relational, scalable, secure databases such as Oracle^® or Sybase^® .

The operating system 907 may facilitate resource management and operation of the computer system 900. Examples of operating systems include, without limitation, APPLE^® MACINTOSH^® OS X^®, UNIX^®, UNIX-like system distributions (E.G., BERKELEY SOFTWARE DISTRIBUTION® (BSD), FREEBSD®, NETBSD®, OPENBSD, etc.), LINUX^® DISTRIBUTIONS (E.G., RED HAT^®, UBUNTU^®, KUBUNTU®, etc.), IBM^® OS/2^®, MICROSOFT^® WINDOWS^® (XP^®, VISTA ®77/8, 10 etc.), APPLE^® IOS^®, GOOGLE ^TM ANDROID ^WI, BLACKBERRY^® OS, or the like.

The user interface 906 may facilitate display, execution, interaction, manipulation, or operation of program components through textual or graphical facilities. For example, the user interface 906 may provide computer interaction interface elements on a display system operatively connected to the computer system 900, such as cursors, icons, check boxes, menus, scrollers, windows, widgets, and tire like. Further, Graphical User Interfaces (GUIs) may be employed, including, without limitation, APPLE® MACINTOSH® operating systems’ Aqua^®, IBM^® OS/2®, MICROSOFT^® WINDOWS^® (e.g., Aero, Metro, etc.), web interface libraries (e.g., ActiveX^®, JAVA^®, JAVASCRIPT®, AJAX, HTML, ADOBE® FLASH^®, etc.), or the like.

The web browser 908 may be a hypertext viewing application. Secure web browsing may be provided using Secure Hypertext Transport Protocol (HTTPS), Secure Sockets Layer (SSL), Transport. Layer Security (TLS), and the like. The web browsers 908 may utilize facilities such as AJAX, DHTML, ADOBE^® FLASH^®, JAVASCRIPT^®, JAVA^®, Application Programming Interfaces (APIs), and the like. Further, the computer system 900 may implement a mail server stored program component. The mail server may utilize facilities such as ASP, ACTIVEX^®, ANSI® C++/C#, MICROSOFT^®, .NET, CGI SCRIPTS, JAVA^®, JAVASCRIPT^®, PERL^®, PHP, PYTHON®, WEBOBJECTS^®, etc. The mail server may utilize communication protocols such as Internet Message Access Protocol (IMAP), Messaging Application Programming Interface (MAPI), MICROSOFT^® exchange, Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), or the like. In some embodiments, the computer system 900 may implement a mail client stored program component. The mail client may be a mail viewing application, such as APPLE^® MAIL, MICROSOFT^® ENTOURAGE^®, MICROSOFT^® OUTLOOK^®, MOZILLA^® THUNDERBIRD^®, and the like.

Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present invention. A computer-readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term “computer-readable medium” should be understood to include tangible items and exclude carrier waves and transient signals, i.e., non-transitory. Examples include Random Access Memory (RAM), Read-Only Memory (ROM), volatile memory, nonvolatile memory, hard drives, Compact Disc (CD) ROMs, Digital Video Disc (DVDs), flash drives, disks, and any other known physical storage media.

Advantages of the embodiments of the present disclosure are illustrated herein.

Tn an embodiment, the method of present disclosure helps in estimating a lead thermal indicator of the blast furnace, prior to the hot metal temperature and composition. The estimated lead thermal indicator assists the operators to take early actions required to maintain the desired thermal stability of the blast furnace.

Tn an embodiment, the method of present disclosure helps in adjusting or controlling the operating parameters of the blast furnace. As a result, the thermal stability of the blast furnace is maintained.

In an embodiment, the method of present disclosure controls the controllable parameters of the blast furnace at an earlier stage, thereby avoiding chances of thermal disturbance or swing in the blast furnace.

In an embodiment, the method of present disclosure reduces the standard deviation of the hot metal temperature at least by 4° C. Consequently, tire method of present disclosure enhances the operators’ confidence to run the blast furnace smoothly, by controlling the process parameters based on the estimated thermal indicator.

In light of the technical advancements provided by the proposed method and the control system, the claimed steps, as discussed above, are not routine, conventional, or well-known aspects in the art, as the claimed steps provide the aforesaid solutions to the technical problems existing in the conventional technologies. Further, the claimed steps clearly bring an improvement in the functioning of the system itself, as the claimed steps provide a technical solution to a technical problem.

The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the embodiments", "one or more embodiments", "some embodiments", and "one embodiment" mean "one or more (but not all) embodiments of the invention(s)" unless expressly' specified otherwise.

The terms "including", "comprising", “having” and variations thereof mean "including but not limited to", unless expressly specified otherwise.

The enumerated listing of items does not imply that any or all the items are mutually exclusive, unless expressly specified otherwise. The terms "a", "an" and "the" mean "one or more", unless expressly specified otherwise.

A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary', a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

When a single device or article is described herein, it will be clear that more than one device/article (whether they cooperate) may be used in place of a single device/article. Similarly, where more than one device/article is described herein (whether they cooperate), it will be clear that a single device/article may be used in place of the more than one device/article, or a different number of devices/articles may' be used instead of the shown number of devices or programs. "lire functionality and/or features of a device may' be alternatively embodied by one or more other devices which are not explicitly described as having such fimctionality/features. Tirus, other embodiments of invention need not include the device itself.

Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

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 Numerals:

Claims

Claims:

1. A method for determining and controlling thermal level of a blast furnace, the method comprising: acquiring, by a controller (101), real-time values of a plurality of operational parameters associated with the blast furnace using a plurality of devices associated with the blast furnace; determining, by the controller (101), a plurality of chemical properties related to the blast furnace based on predetermined chemical analyses; estimating, by the controller (101), a lead thermal indicator of the blast furnace by analysing the real-time values of the plurality of operational parameters and the plurality of chemical properties; and determining, by the controller (101), optimal values of the plurality of operational parameters for controlling the thermal level of the blast furnace within a predefined temperature range.

2. The method as claimed in claim 1, wherein the plurality of operational parameters comprises at least one of: flow rates of at least one of wind, oxygen, steam, top gas, cooling water, injected coal conveying medium and gaseous/Iiquid fuels; blast temperahire comprising wind, oxygen, and steam before entering tuyere, inlet and outlet temperature of cooling water required for blast furnace cooling, hot metal temperature leaving blast furnace during cast and temperature of injected fuels; concentration of Carbon monoxide (CO), Carbon Dioxide (CO₂) and Hydrogen (H₂) in top gas of the blast furnace; weights of burden materials comprising at least one of coke, iron bearing materials and fluxes; and moisture levels of the burden materials comprising at least one of coke and iron bearing materials.

3. The method as claimed in claim 1, wherein the plurality of devices associated with the blast furnace comprises one or more flow meters, temperature sensors, gas analysers, weighing devices and moisture analysers. The method as claimed in claim 1, wherein the plurality of chemical properties comprises at least one of: ultimate and proximate analyses of fuels comprising at least one of coke and coal; chemical composition of iron bearing materials comprising at least one of flue dust and fluxes and weight percentage of total Iron (Fe) and Ferrous Oxide (FeO); chemical composition of hot metal and slag; and calorific value of injectant fuels comprising at least one of coal, tar, and natural gas. The method as claimed in claim 1 comprises performing, by the controller (101), one or more pre-processing operations on the real-time values of the plurality of operational parameters and the plurality of chemical properties before estimating the lead thermal indicator of the blast furnace. The method as claimed in claim 5, wherein the one or more pre-processing operations comprises: a data cleansing operation for removing negative values, values outside min- max range and empty values; an averaging operation for averaging of periodic data comprising at least one of temperature, flow rates and gas composition; a summing operation for summing of burden weights; and regularizing infrequent data based on last available data, until next measured data is available. The method as claimed in claim 1, wherein estimating the lead thermal indicator comprises: dividing the blast furnace virtually into a plurality of zones based on difference in temperature at different regions of the blast furnace, wherein the plurality of zones comprises at least one of a lower zone and a thermal reserve zone; determining value of a heat balance factor corresponding to the lower zone based on analysis of the real-time values of the plurality of operational parameters and the plurality of chemical properties; and estimating the lead thermal indicator by subtracting values of one or more heat loss parameters from the value of the heat balance factor. The method as claimed in claim 7, wherein the one or more heat loss parameters comprises at least one of coal dissociation heat, heat loss to wall of the lower zone and limestone decomposition heat. A control system ( 100) for determining and controlling thermal level of a blast furnace, the system comprising: a controller (101); and a memory’ (103), communicatively’ coupled to the controller (101), wherein the memory (103) stores data and instructions, which cause the controller (101) to: acquire real-time values of a plurality of operational parameters associated with the blast furnace using a plurality' of devices (117) associated with the blast furnace; determine a plurality of chemical properties related to the blast furnace based on predetermined chemical analy ses; estimate a lead thermal indicator of the blast furnace by analysing the real-time values of the plurality of operational parameters and the plurality of chemical properties; and determine optimal values of the plurality of operational parameters for controlling the thermal level of the blast furnace within a predefined temperature range. The control system (100) as claimed in claim 9, wherein the plurality of operational parameters comprises at least one of: flow rates of at least one of wind, oxygen, steam, top gas, cooling water, injected coal conveying medium and gaseous/liquid fuels; blast temperature comprising wind, oxygen, and steam before entering tuyere, inlet and outlet temperature of cooling water required for blast furnace cooling, hot metal temperature leaving blast furnace during cast and temperature of injected fuels; concentration of Carbon monoxide (CO), Carbon Dioxide (CO₂) and Hydrogen (H2) in top gas of the blast furnace; weights of burden materials comprising at least one of coke, iron bearing materials and fluxes; and moisture levels of the burden materials comprising at least one of coke and iron bearing materials, Idle control system (100) as claimed in claim 9, wherein the plurality of devices (117) associated with the blast furnace comprises one or more flow meters, temperature sensors, gas analysers, weighing devices and moisture analysers. The control system (100) as claimed in claim 9, wherein the plurality' of chemical properties comprises at least one of: ultimate and proximate analyses of fuels comprising at least one of coke and coal; chemical composition of iron bearing materials comprising at least one of flue dust and fluxes and weight percentage of total Iron (Fe) and Ferrous Oxide (FeO); chemical composition of hot metal and slag; and calorific value of injectant fuels comprising at least one of coal, tar, and natural gas. lire control system (100) as claimed in claim 9, wherein the controller (101) performs one or more pre-processing operations on the real-time values of the plurality of operational parameters and the plurality of chemical properties before estimating the lead thermal indicator of the blast furnace. The control system (100) as claimed in claim 17, wherein the one or more preprocessing operations comprises: a data cleansing operation for removing negative values, values outside min- max range and empty values; an averaging operation for averaging of periodic data comprising at least one of temperature, flow rates and gas composition; a summing operation for summing of burden weights; and regularizing infrequent data based on last available data, until next measured data is available. The control system (100) as claimed in claim 9, wherein the controller (101) estimates the lead thermal indicator by: dividing the blast furnace virtually into a plurality of zones based on difference in temperature at different regions of the blast furnace, wherein the plurality of zones comprises at least one of a lower zone and a thermal reserve zone; determining value of a heat balance factor corresponding to the lower zone based on analysis of the real-time values of the plurality of operational parameters and the plurality of chemical properties; and estimating the lead thermal indicator by subtracting values of one or more heat loss parameters from the value of the heat balance factor. The control system (100) as claimed in claim 15, wherein the one or more heat loss parameters comprises at least one of coal dissociation heat, heat loss to wall of the lower zone and limestone decomposition heat.