Claims:
1. A method for determining source and quantify a carbon content in a sludge from a blast furnace, the method comprising:
reducing, mass of the sludge by heating at a first substantially constant temperature for a first predefined time period for a fixed mass of sludge;
subsequently increasing, the temperature of the sludge to a second constant temperature for a second predefined time period and at a predefined pressure for the fixed mass of sludge;
monitoring, percentage of mass loss at the first constant temperature and at the second constant temperature; and
quantifying the carbon content from different sources constituted in the sludge based on the percentage of mass loss of the sludge being monitored at different temperatures.

2. The method as claimed in claim 1, wherein the sludge is collected from a gas cleaning plant of the blast furnace.

3. The method as claimed in claim 1, wherein the sludge is constituted from carbon containing materials including char and coke.

4. The method as claimed in claim 3, wherein char is at least one of char in the sludge obtained from the coal injected into blast furnace as pulverized coal, and unburnt carbon coming as char from combustion and gasification.

5. The method as claimed in claim 1, wherein the first constant temperature and the second constant temperature are determined corresponding to mass loss detected upon testing pure char and coke independently.

6. The method as claimed in claim 1, wherein the sludge is reduced by oxidation of carbon content.

7. The method as claimed in claim 1, wherein an oxidation temperature of carbon in char is lower than the oxidation temperature of carbon in coke.

8. The method as claimed in claim 1, wherein the sludge is maintained in an oxidizing environment for reducing the mass of sludge at the first constant temperature and the second constant temperature.

9. The method as claimed 8, wherein the oxidizing environment is created by supplying synthetic air mixture including argon and oxygen.

10. The method as claimed in claim 1, wherein the char in the sludge is reduced at the first constant temperature and first predefined time period.

11. The method as claimed in claim 1, wherein the coke in the sludge is reduced at the second constant temperature and second predefined time period.

12. The method as claimed in claim 1, wherein the first constant temperature is in a temperature range of 400-520℃ and the second constant temperature is in a temperature range of 570-620℃.

13. The method as claimed in claim 1, wherein the carbon content from char is determined from the percentage of mass loss at the first constant temperature.

14. The method as claimed in claim 1, wherein the carbon content from coke is determined from the percentage of mass loss at the second constant temperature.

15. The method as claimed in claim 1, wherein the source of carbon content, of the sludge is monitored to recommend quality parameters corresponding to coke and char combustion.
, Description:TECHNICAL FIELD
Present disclosure, in general, relates to the field of metallurgy. Particularly, but not exclusively, the present disclosure relates to a method for determining carbon content in the sludge of a blast furnace. Further, embodiments of the present disclosure disclose a method for determining source and quantify carbon content in the sludge from the blast furnace.

BACKGROUND OF THE DISCLOSURE

Generally, iron is produced by employing a blast furnace. The blast furnace is fed with iron ore (iron oxides), coke and fluxing materials as raw materials. The coke is charged into the blast furnace in different sizes and iron ore are charged typically in the form of lump ore, pellets, and sinter from the top of the blast furnace. The coke upon charging is configured to react with oxygen being supplied in form of blast air, to produce carbon monoxide. The carbon monoxide is configured to travel as upward flowing gas, which reduces the descending iron ore. In addition, carbon in the form of pulverized coal is injected from tuyeres in a lower part of the blast furnace. The rate of injection of the pulverized coal and high temperature properties of the raw materials affects performance of the blast furnace. Further, dusts formed upon degradation of the iron ore, coke, fluxing material, and unburnt coal from the tuyeres is removed from the blast furnace in the form of a top gas.

The top gases from the blast furnace are cleaned in a gas cleaning plant and the cleaned top gasses are channelized out of the gas cleaning plant. The gas cleaning plant filters the top gasses and collects a sludge which constitutes of carbon and gangue. The gangue is the unwanted material present in the iron ore. A typical composition of the sludge in mass percentage is shown in Table 1.
Fe CaO SiO2 MgO MnO Al2O3 TiO2 Cr2O3 K2O Na2O C P MOISTURE
30.2 2.67 4.07 2.29 0.001 4.01 0.282 0.001 0.19 0.029 31.6 0.28 24
Table.1: Typical Composition of Sludge
The sludge collected at the gas cleaning plant is composed mostly of carbon, iron, and moisture. The carbon in the sludge indirectly indicates an actual carbon usage inside blast furnace. For example, more the amount of carbon more inefficient is the operation of the blast furnace.

With advent of technology, the amount of carbon from the sludge collected in the gas cleaning plant is determined by employing a Loss of Ignition (LOI) method. Further, source of the carbon in the sludge is also a one of the factors as high quantities of carbon in the sludge may be due to inefficient pulverized coal combustion which generates unburnt char or poor coke quality. However, the loss of ignition (LOI) method does not provide any information regarding different forms of carbon sources involved in the sludge. Furthermore, other conventional methods such as optical image analysis, X-ray diffraction provide information regarding a distinct material and are unable to quantify the carbon form individual carbon source.

The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the conventional mechanisms.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of the prior art 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 source and quantify a carbon content in a sludge from a blast furnace is disclosed. The method includes reducing mass of the sludge by heating at a first substantially constant temperature for a first predefined time period for a fixed mass of sludge. Further, the temperature of the sludge is subsequently increased to a second constant temperature for a second predefined time period and at a predefined pressure for the fixed mass of sludge under synthetic air or oxidizing atmosphere. Further, a percentage of mass loss is monitored at the first constant temperature and at the second constant temperature. Upon monitoring the percentage of mass loss at different temperatures, the carbon content is quantified from different sources constituted in the sludge based on the percentage of mass loss of the sludge.

In an embodiment, the sludge is collected from a gas cleaning plant of the blast furnace.

In an embodiment, the sludge is constituted from carbon containing materials including char and coke.

In an embodiment, the char is at least one of char in the sludge obtained from the coal injected into blast furnace as pulverized coal, and unburnt carbon coming as char from combustion and gasification.

In an embodiment, the first constant temperature and the second constant temperature are determined corresponding to mass loss detected upon testing pure char and coke independently.

In an embodiment, the sludge is reduced by oxidation of carbon content.

In an embodiment, an oxidation temperature of carbon in char is lower than the oxidation temperature of carbon in coke.

In an embodiment, wherein the sludge is maintained in an oxidizing environment for reducing the mass of sludge at the first constant temperature and the second constant temperature.

In an embodiment, the oxidizing environment is created by supplying synthetic air mixture including argon and oxygen.

In an embodiment, the char in the sludge is reduced at the first constant temperature and first predefined time period.

In an embodiment, the coke in the sludge is reduced at the second constant temperature and second predefined time period.

In an embodiment, the first constant temperature is in a temperature range of 400-520℃ and the second constant temperature is in a temperature range of 570-620℃.

In an embodiment, the carbon content from char is determined from the percentage of mass loss at the first constant temperature.

In an embodiment, the carbon content from coke is determined from the percentage of mass loss at the second constant temperature.

In an embodiment, the source of carbon content, of the sludge is monitored to recommend quality parameters corresponding to coke and pulverized coal combustion.

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 characteristic 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 embodiments 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 graphical representation illustrating a mass loss of char and coke based on temperature and time.

Figure 2 is a graphical representation illustrating the mass loss of char and coke based on temperature.

Figure 3 is a flow chart of a method for determining source and quantify a carbon content in a sludge from a blast furnace, in accordance with an 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 method illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that, the conception and specific embodiments disclosed may be readily utilized as a basis for modifying other methods, mechanisms, systems, assemblies, devices, and processes for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that, such equivalent constructions do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristics of the disclosure, to its system, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a mechanism, an assembly, or a device 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 apparatus.

In accordance with various embodiments of the present disclosure, a method for determining source and quantify a carbon content in a sludge from a blast furnace is disclosed. The method includes reducing mass of the sludge by heating at a first substantially constant temperature for a first predefined time period for a fixed mass of sludge. Further, the temperature of the sludge is subsequently increased to a second constant temperature for a second predefined time period and at a predefined pressure for the fixed mass of sludge under synthetic air or oxidizing atmosphere. Further, a percentage of mass loss is monitored at the first constant temperature and at the second constant temperature. Upon monitoring the percentage of mass loss at different temperatures, the carbon content is quantified from different sources constituted in the sludge based on the percentage of mass loss of the sludge.

Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals will be used to refer to the same or like parts. The following paragraphs describe the present disclosure with reference to Figure 1.

A blast furnace is a type of a metallurgical furnace employed for smelting and for producing industrial metals including but not limited to pig iron, lead, copper, and the like. The blast furnace operates by forcibly supplying combustible air above atmospheric pressure. In a blast furnace, fuel such as coke, coal [hereafter referred to as char] and flux (for example, limestone) are continuously supplied to the blast furnace, while a hot blast of air is blown into a lower section of the blast furnace through a series of tuyeres. The hot blast of air enables chemical reactions to take place throughout the furnace as the material flows downward. Molten metal and slag get tapped at a bottom of the blast furnace, and waste gases produced during combustion process exit from a top of the blast furnace. The waste gasses are processed in a gas cleaning plant (GCP), where a sludge is filtered from the gasses.

Further, the blast furnace to function at a desired efficiency, the combustion process may be to be monitored. To monitor the combustion process, the sludge collected in the gas cleaning plant may be processed as the sludge may contain carbon. The quantity of carbon in the sludge may be indicative of efficiency of the combustion process in the blast furnace. Furthermore, the efficiency of the combustion process may be varied by altering quality of raw materials fed into the blast furnace. In an embodiment, majority of carbon in the sludge may be obtained from at least one of char and coke, i.e., the sludge is constituted from carbon containing materials including the char and the coke.

Figure 1 illustrates a graphical representation of a mass loss of the char and the coke based on normalized temperature and normalized time for a method of determining source and quantify a carbon content in the sludge from the blast furnace. The method includes heating a fixed mass of the sludge at a first substantially constant temperature for a first predefined time period [as seen in section A-A in Figure 1]. At the first substantially constant temperature, carbon obtained from the char may be oxidized. Upon oxidation of carbon obtained from the char at the first constant temperature for the first predefined time period, the sludge experiences mass loss which may be monitored and recorded by an operator either manually or through a control unit [not shown]. After the first predefined time period, temperature of the fixed mass of the sludge may be subsequently increased to a second constant temperature. The sludge at the second constant temperature may be maintained for a second predefined time period. At the second constant temperature, the carbon obtained from the coke may be oxidized [as seen in section B-B in Figure 1]. In an embodiment, the first constant temperature may be in a temperature range of 400-520℃ and the second constant temperature may be in a temperature range of 570-620℃ [as seen in Figure 2]. The first constant temperature may be lower than the second constant temperature, as an oxidation temperature of carbon in the char may be lower than the oxidation temperature of carbon in the coke.

Upon oxidation of the carbon obtained from the coke, the sludge experiences further mass loss which may be monitored and recorded. Further, the mass loss experienced by the sludge may recorded as a percentage of the mass loss at the first constant temperature and at the second constant temperature. The carbon content from the char and the coke in the sludge may be quantified based on percentage of the mass loss at the first constant temperature and the second constant temperature, respectively. Upon quantification, quantity of carbon oxidized individually from each of the char and the coke may be recorded. Additionally, the source of carbon content i.e., the char and the coke, of the sludge may be monitored to indicate quality parameters corresponding to combustion of the char and the coke fed into the blast furnace.

Further, as can be seen in Figure 1, the fixed mass of sludge when heated to the first constant temperature experiences mass loss. The mass loss may be observed for a duration of the first predefined time period at which carbon in the sludge obtained from the char is oxidized. At the start of the first predefined time period the percentage of mass loss may be high and the percentage of mass loss decreases gradually towards the end of the first predefined time period until the percentage of mass lost is zero. After the first predefined time period the temperature of the sludge is gradually increased to a second constant temperature where the sludge is maintained for the second predefined time period. At the start of the second predefined time period the percentage of mass loss may be high and the percentage of mass loss decreases gradually towards the end of the second predefined time period until the percentage of mass lost is zero. The total amount of percentage of mass loss for the first predefined time period at the first constant temperature may be used to quantify the amount of carbon in the sludge from the char. Additionally, total amount of percentage of mass loss for the second predefined time period at the second constant temperature may be used to quantify the amount of carbon in the sludge from the coke.

In an embodiment, the heating of the fixed mass of sludge at the first constant temperature and the second constant temperature may be carried out under synthetic air or oxidizing atmosphere at predefined pressure. The predefined pressure may be including but not limited to atmospheric pressure and any other pressure suitable for oxidation of carbon in the sludge.

In an embodiment, the char may be at least one of char in the sludge obtained from the coal injected into the blast furnace as pulverized coal, and unburnt carbon coming as char from combustion and gasification in the blast furnace.

In an embodiment, the sludge may be maintained in an oxidizing environment for reducing the mass of the sludge at the first constant temperature and the second constant temperature. The oxidizing environment may be created by including but not limited to supplying a synthetic air mixture including argon and oxygen and any other gasses which aid in oxidation of carbon in the sludge. Further, the synthetic air mixture may include 79% v/v of Argon added with 21% v/v of oxygen.

In an embodiment, the temperature ranges of the first constant temperature and the second constant temperature may be determined corresponding to mass loss detected upon testing pure char and coke independently.

Referring now to Figure 2, which illustrates a graphical representation of the mass loss of char and the coke based on temperature for identifying the first constant temperature and the second constant temperature. The char and the coke may be individually heated at different rates, which may vary from 2ºC/min to 5ºC/min at 1ºC interval with temperature varying from ambient temperature to 1000°C. The synthetic air mixture of argon (79% v/v) and oxygen (21% v/v) may be employed as the oxidizing environment. The gradient of mass loss (dm/dt) with time is analyzed for the char and the coke for different heating rates. A peak mass loss in temperature range of 400-520ºC has been observed for char [as seen in the first peak of Figure 2] and another peak mass loss at 570ºC-620ºC has also been observed for coke for all heating rates [as seen in the second peak of Figure 2]. The peak mass losses correspond to maximum reactivity at low temperature and high temperature for the corresponding carbon sources, which may have dependency on heating rate and time. Further, the predefined time period may also be determined by monitoring the amount of mass loss at the first constant temperature and the second constant temperature. The predetermined time period may be calculated based on time required to completely reduce the carbon indicated by a halt in the mass loss at the corresponding constant temperature.

In an embodiment, as the temperature reaches the at least one first constant temperature and the second constant temperature, the carbon may be oxidized, and the mass loss may occur.

In an embodiment, the heating may be performed in but not limited to a closed environment. Further, the heating may be performed in an open environment.

Referring now to Figure 3 which is an exemplary embodiment of the present disclosure illustrating a flow chart of the method for determining the source and quantify the carbon content in a sludge.

The order in which the method 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. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein.

At block 301, the mass of the sludge may be reduced by heating the fixed amount of sludge at the first constant temperature for the first predefined time period at a predefined pressure.

At block 302, the temperature of the sludge may be subsequently increased from the first constant temperature to the second constant temperature. The second constant temperature may be maintained for the second predefined time period such that the mass of the sludge reduces for the second time.

At block 303, the percentage of mass loss at the first constant temperature and at the second constant temperature may be monitored and recorded.

At block 304, The carbon content from different sources constituted in the sludge may be quantified based on the percentage of mass loss monitored and recorded at the first constant temperature and at the second constant temperature. The mass loss at the first constant temperature may indicate the amount of the carbon in the sludge obtained from char and the mass loss at the second constant temperature may indicate the amount of the carbon in the sludge obtained from coke.

Exemplary Experimental analysis

Following paragraphs may be illustrate exemplary experimental results illustrating accuracy of the method disclosed in blocks 301, 302, 303 and 304 to quantify and identify the source of the carbon.

The experiment was conducted with known mixtures of char and coke, where the theoretical carbon values are compared with the experimental values obtained by reducing the sludge by the method disclosed in blocks 301, 302, 303 and 304. The values obtained in the experiment are recorded as seen in Table 1 below.

Synthetic Mix Char (wt%) 80 60 Actual GCP Sludge
Coke (wt%) 20 40
Theoretical Cchar 66.37 49.78 44
(% Total Carbon)
Ccoke 16.43 32.87
Experiment result Cchar 66.66 49.49 16.70
Ccoke 14.42 30.53 25.93
Cchar : Carbon from Coal-Char
Ccoke : Carbon from Coke

The quantity of carbon obtained by individually processing the char and the coke was monitored. Further, theoretical values of carbon for a known synthetic mixture of char and coke were identified based on the weight percentage of the char and coke in the synthetic mixture. The synthetic mixture was then processed by the method disclosed in blocks 301, 302, 303 and 304. A mass of the synthetic mixture was reduced by heating the synthetic mixture at the first substantially constant temperature for the first predefined time period. Further, the temperature of the sludge was subsequently increased to the second constant temperature and was maintained for the second predefined time period where the mass of the synthetic mixture was reduced to an even lower value. The percentage of mass loss was monitored at the first constant temperature and at the second constant temperature. Upon monitoring the percentage of mass loss at the different temperatures, the carbon content was quantified from different sources constituted in the synthetic mixture based on the percentage of mass loss of the synthetic mixture. The carbon content quantified by the method for the known mixture of the char and the coke was similar to the carbon content monitored during theoretical analysis.

In an embodiment, the method includes a customized heating program with defined heating rate, hold temperatures and hold time to have controlled reactions (oxidation) under the synthetic air.

In an embodiment, the method clearly separates the peaks corresponding to oxidation of different carbon sources in the sludge obtained from the gas cleaning plant of the blast furnace, to quantify the amount of the carbon from different carbon sources.

In an embodiment, the method differentiates and quantifies the carbon from different carbon sources. Further, the method employs difference in reactivity behavior of individual carbon sources under atmospheric environment at different temperatures to quantify the carbon sources replacing conventional techniques such as loss of ignition method, optical image analysis or X-ray diffraction technique.

In an embodiment, the method may be employed to estimate efficiency of pulverized coal combustion inside the blast furnace. Further, the method may be employed to benchmark the metallurgical coke quality parameters.

In an embodiment, the method may be employed to calculate the carbon loss from the blast furnace by processing the sludge collected from the gas cleaning plant and flue dust.

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 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 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.