, Description:TECHNICAL FIELD
[0001] The present disclosure described herein, in general, relates to reducing the starting temperature of coke gasification or solution loss reaction and thereby, improvement or enhancement of the coke reactivity index (CRI) of nut coke by using low-value solid waste as a catalyst that is generated from an integrated steel plant.
[0002] In particular, the present disclosure relates to a process and a system for the production of a catalyst coated nut coke for blast furnace application.
BACKGROUND
[0003] The background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed subject matter, or that any publication specifically or implicitly referenced is prior art.
[0004] In the present scenario, nut coke which has a size range of 10 mm to 30 mm are charged with metallic burden in blast furnaces in addition to blast furnace (BF) coke which have a size range of about 30 mm to 80 mm. The reason behind the increased application of the nut coke in the blast furnace is its smaller size than the BF coke, which imparts a higher coke reactivity index (CRI) to the nut coke than the BF coke. The higher CRI of the nut coke over the BF coke results in the provision of following benefits:
• Effective utilization of low-value products (nut coke) generated during the carbonization of coking coal.
• Reduction of BF coke consumption at the blast furnace.
• Improvement in blast furnace productivity
• Reduction of the production cost of hot metal.
• Use of nut coke in the blast furnace reduces overall emissions of CO2 of the steel plant
[0005] The above-mentioned benefits can further be enhanced by reducing the starting temperature of solution loss reaction and thereby increasing the CRI of the nut coke. This in turn reduces the temperature of thermal reserve zone (TRZ) and improves the blast furnace reaction efficiency. The increase in CRI of the coke, in general, is achieved by two ways - (i) by addition of a catalyst in coal or coal blend before coke making process, known as pre-addition process, or (ii) by coating of the catalyst on the coke surface after coke making process, known as post-addition process. Generally, the post-addition process is practiced over the pre-addition process because it helps in maintaining the coke strength after reaction (CSR) while giving an increased CRI.
[0006] In existing post-addition process for increasing the CRI of coke, in general, involves spraying on the coke, an aqueous solution containing a predetermined amount of iron (Fe), calcium oxide (CaO), nickel (Ni) and an aqueous solution of ammonia (NH3) and hydrochloric acid (HCl), which acts as a catalyst. The process, however, leads to an increase in chlorine content of the coke which is detrimental to the blast furnace operation. In another existing post-addition process for increasing the CRI of coke, in general, alkaline earth metals or their compounds and transition metals or their compounds are used as a catalyst for increasing the CRI. The process, is, however, cannot be performed on a commercial level.
[0007] In addition, the above-disclosed existing post-addition processes pose some more unavoidable drawbacks. The processes are not disclosed specifically for nut coke as nut coke have different behavioral characteristics in the blast furnace operation as compared to coke in general. The processes further don’t increase or enhance the CRI of the coke and reduction in the temperature of the thermal reserve zone (TRZ) to an appreciable amount. The additional cost of the catalysts used in the above-mentioned processes further leads to an increase in the cost of the blast furnace operation.
[0008] In view of the above, there is a need to provide a post-addition process for the production of a catalyst coated coke, specifically nut coke for blast furnace application which overcomes the shortcomings of the above processes. The present disclosure is also directed to provide a system for the production of a catalyst coated nut coke for blast furnace application.
OBJECTS OF THE DISCLOSURE
[0009] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0010] It is a general object of the present disclosure to provide a process and a system for production of a catalyst coated nut coke for blast furnace application that provides a considerable increase in the coke reactivity index (CRI) and reduction in the temperature of thermal reserve zone (TRZ).
[0011] It is another object of the present disclosure to provide a process and a system for the production of a catalyst coated nut coke that doesn’t increase the cost of the blast furnace operation.
[0012] It is yet another object of the present disclosure to provide a process and a system for the production of a catalyst coated nut coke that can be practiced commercially.
[0013] These and other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings.
SUMMARY
[0014] This summary is provided to introduce concepts related to a process and a system for the production of a catalyst coated nut coke for blast furnace application. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0015] The subject matter disclosed herein relates to a process for producing catalyst coated nut coke. The process begins with adding of a catalytic material in a slurry preparation tank, wherein the catalytic material comprises calcined lime fines and iron-bearing fines in a weight ratio of 2:1. The catalytic material is then mixed with water in the slurry preparation tank to form a catalyst slurry which is then pumped by a slurry transfer pump installed at a discharge point of the slurry preparation tank to one or more spray headers mounted above different conveyor belts through a transfer line from the discharge point. The conveyor belts transfer nut coke from a nut coke hopper to a wagon that carries the nut coke to blast furnace. Each spray header is provided with a respective nozzle to form fine droplets of the catalyst slurry and is triggered to spray the catalyst slurry on the nut coke moving on the conveyor belts so as to produce the catalyst coated nut coke.
[0016] The subject matter disclosed herein further relates to a system for producing catalyst coated nut coke. The system comprises a slurry preparation tank for preparing a catalyst slurry by mixing a catalytic material and water, wherein the catalytic material is composed of calcined lime fines and iron-bearing fines in a weight ratio of 2:1; a slurry transfer pump installed at a discharge point of the slurry preparation tank to pump the catalyst slurry through a transfer line from the discharge point to one or more spray headers mounted above different conveyor belts that transfers nut coke from a nut coke hopper to a wagon which carries nut coke to blast furnace; and a plurality of nozzles which are provided at each respective spray headers to form fine droplets of the catalyst slurry, wherein the nozzles are triggered to spray the catalyst slurry on the nut coke moving on the conveyor belts so as to produce the catalyst coated nut coke.
[0017] In an aspect, the catalytic material is a solid waste that is generated from an integrated steel plant only. Therefore, the additional cost of catalytic material is obviated and the overall cost of the blast furnace operation isn’t affected.
[0018] Since the weight ratio of calcined lime fines and iron-bearing fines (catalytic material) are mixed in a weight ratio of 2:1 and in an aspect, the ratio of catalytic material to water in the catalytic slurry is 1:2.5, the coke reactivity index (CRI) of the nut coke is increased and temperature of thermal reserve zone (TRZ) is decreased considerably.
[0019] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.
[0020] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[0022] FIG. 1 illustrates a system for the production of catalyst coated nut coke in accordance with the present disclosure;
[0023] FIG. 2 illustrates a process for the production of catalyst coated nut coke in accordance with the present disclosure;
[0024] FIG. 3 illustrates a graph depicting the starting temperature of solution loss reaction (SLR) for catalyst coated nut coke and uncoated nut coke; and
[0025] FIG. 4 illustrates the stats for the coke reactivity index (CRI), coke strength after reaction (CSR) and moisture content of catalyst coated nut coke and uncoated nut coke.
[0026] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0027] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0028] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0030] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0031] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0032] The present disclosure provides a system for the production of catalyst coated coke, specifically nut coke for blast furnace application which overcomes the shortcomings of the existing post-addition processes. Accordingly, FIG. 1 shows the layout of the system which comprises a slurry preparation tank 100 which is used to prepare a catalyst slurry by mixing a catalytic material with water in a predefined quantity. In an exemplary embodiment, the slurry preparation tank 100 is made of mild steel coated with fiber-reinforced plastic (FRP) lining and has a volume of 7m3. The slurry preparation tank 100 is broadly equipped with a feed hopper 102, a water inlet line 104, an agitator 106 and a slurry recirculation line 108. The feed hopper 102 is used to feed the catalytic material into the slurry preparation tank 100. The catalytic material is composed of calcined lime fines and iron-bearing fines which are fed into the slurry preparation tank 100 in a weight ratio of 2:1. The composition or chemical analysis of calcined lime fines and iron-bearing fines used as the catalytic material in the present disclosure is mentioned in the following Table 1 and Table 2, respectively.
Table 1: Chemical analysis of lime fines generated from the lime plant
Constituents Fe(T) CaO SiO2 Al2O3 MgO K2O Na2O P2O5 LOI
Value, % 1.86 69.15 1.14 0.28 1.28 0.022 0.023 0.012 27.64

Table 2: Chemical analysis of iron-bearing fines generated from the steelmaking process
Constituents Fe(T) CaO SiO2 Al2O3 MgO MnO K2O Na2O P2O5 LOI
Value, % 28.21 29.26 4.31 1.75 2.66 0.7 1.33 0.16 1.86 19.02

[0033] The catalytic material used is the solid waste generated from the integrated steel plant and hence no additional cost is incurred on catalytic material. The water inlet line 104 is used to supply water into the slurry preparation tank 100. A flow meter 104a and a regulating valve 104b are arranged in the water inlet line 104 to control and monitor the amount of water flowing into the slurry preparation tank 100. The water inlet line 104 is branched into another supply line 104c connected at a discharge point of the slurry preparation tank 100. The pipeline 104c also comprises a regulating valve 104d which is used to flush the recirculation line and discharge line with water after completion of coating process to avoid the settling of solid materials in pipeline and spray nozzles. The agitator 106 vigorously mixes the catalytic material with water for about 10 to 15 minutes (extendable) to form catalyst slurry. In an aspect, the agitator 106 operates at a speed range of 50 to 200 revolutions per minute (RPM) using a variable frequency drive (VFD). The catalyst slurry preparation is done in batches. The recirculation line 108 is connected to the water inlet line 104 near the slurry preparation tank inlet of slurry preparation tank 100 for recirculating the catalyst slurry to allow it to mix again. The recirculation line 108 is equipped with a flowmeter 108a and a regulating valve 108b to control and monitor the flow of the catalyst slurry. In operation, after the catalyst slurry is formed it is passed through the discharge point of the slurry preparation tank 100 where a basket filter 110 is installed which prevents coarser slurry particles from entering a slurry transfer pump 112. Option provided to takeout and clean the filter mesh loaded with coarser particles. In the prepared catalyst slurry, the ratio of the catalytic material to water is 1:2.5 on a weight basis. The slurry transfer pump 112 is also installed near the discharge point of the slurry preparation tank 100 after the basket filter 110. A drain line (not given reference numeral) is connected at another side of the slurry preparation tank 100 to pass the drain of the slurry preparation tank 100 through it. The slurry transfer pump 112 pumps the catalyst slurry to the recirculation line 108 and to a plurality of spray headers through a transfer line 114 from the discharge point. A flowmeter 114a and a number of regulating valves 114b, 114c, 114d, 114e are arranged in the transfer line 114 for controlling and monitoring the flow of catalyst slurry. The slurry transfer pump 112 operates in two ways – i) when the catalyst slurry is to be recirculated for better mixing, the regulating valves 114b, 114c, 114d, and 114e are closed and ii) when the catalyst slurry is mixed well and is ready for coating, the regulating valve 108b remains closed. The slurry transfer pump 112 can be but not limited to a centrifugal pump piston pump, gear pump, vane pump, etc. The spray headers are mounted above a plurality of conveyor belts 116. In an exemplary embodiment, the number of conveyor belts is two 116a and 116b. The conveyor belts 116a, 116b are used for transferring the uncoated nut coke from a nut coke hopper 118 to a wagon which will carry the catalyst coated nut coke to blast furnace. The nut coke hopper 118 comprises a vibro-feeder whose frequency is adjusted so as to adjust and maintain the mass flow rate of the nut coke on the conveyor belt 116a. The mass flow rate of the nut coke on the conveyor belts 116a, 116b is further adjusted and maintained by controlling the conveyor belt speed. Each of the spray headers is provided with a plurality of nozzles 120. In an exemplary embodiment, two nozzles 120a, 120b are provided over conveyor belt 116a and a single nozzle 120c is provided over conveyor belt 116b. In an alternate embodiment, the two nozzles 120a, 120b can be provided over conveyor belt 116b and a single nozzle 120c can be provided over conveyor belt 116a.The nozzles are triggered by an operator who is monitoring or operating the system to spray the catalyst slurry on the nut coke moving on the conveyor belts 116a, 116b so as to produce the catalyst coated nut coke. The nozzles help in providing highly atomized and uniform coating of the catalyst slurry on the nut coke. Further, by using a plurality of conveyor belts 116, two in the present case, multiple passing of the nut coke is achieved which facilitates proper and uniform coating of the catalyst slurry over the nut coke which helps in yielding a better end product i.e. catalyst coated nut coke. The system also comprises a plurality of compressed air lines 122 for blowing compressed air on the nut coke moving on the conveyor belts 116a and 116b so as to reduce or control the moisture content of the nut coke up till the desired value. In an exemplary embodiment, a compressed air line 122a is provided near the discharge end of the conveyor belt 116a and a compressed air line 122b is provided near the receiving end of the conveyor belt 116b.
[0034] The present disclosure also provides a process for the production of catalyst coated coke, specifically nut coke for blast furnace application. Accordingly, FIG. 2 shows the steps of the process 200. The process 200 is to be performed by the components of the system as disclosed above. The order in which the process 200 is described is not intended to be construed as a limitation, and any number of the described process blocks can be combined in any appropriate order to carry out the process 200 or an alternative process. Additionally, individual blocks may be deleted from the process 200 without departing from the scope of the subject matter described herein.
[0035] At block 202, the process 200 includes adding the catalytic material in the slurry preparation tank 100, wherein the catalytic material comprises calcined lime fines and iron-bearing fines in a weight ratio of 2:1. The composition or chemical analysis of calcined lime fines and iron-bearing fines used as the catalytic material in the present disclosure is mentioned in Table 1 and Table 2, respectively.
[0036] At block 204, the next step of the process 200 involves mixing of the catalytic material with water with the help of the agitator 106 in the slurry preparation tank 100 to form a catalyst slurry. In an aspect, the ratio of the catalytic material to water is 1:2.5 on a weight basis.
[0037] At block 206, the process 200 proceeds with pumping of the catalyst slurry, by the slurry transfer pump 112 installed near the discharge point of the slurry preparation tank 100 from the discharge point through a transfer line to one or more spray headers mounted above the different conveyor belts 116a, 116b that transfers the nut coke from the nut coke hopper 118 to the wagon which carries the catalyst coated nut coke to blast furnace for operation. In an aspect, at the discharge point of the slurry preparation tank 100, the basket filter 110 prevents coarser particles of the catalyst slurry from entering the slurry transfer pump 112. Also, in an aspect, the spray headers being provided with respective nozzles 120a, 120b, 120c so as to form finely atomized droplets of the catalyst slurry.
[0038] At block 208, the nozzles 120a, 120b, and 120c are triggered by, for example, the operator, to spray the catalyst slurry on the nut coke which is moving on the conveyor belts 116a, 116b for producing the catalyst coated nut coke indicated by reference numeral 208. During the spraying of the catalyst slurry, compressed air line 122a, 122b blow compressed air on the moving nut coke so as to reduce or control the moisture content. The process 200 also involves recirculating the catalyst slurry through the recirculation line 108 connected to the water inlet line 104 near the slurry preparation tank inlet. In the process 200, the regulating valves 108b, 114b, 114c, 114d, 114e control the flow of the catalyst slurry.
[0039] In an aspect, the catalytic material is a solid waste that is generated from an integrated steel plant only. Therefore, the additional cost of catalytic material is obviated and the overall cost of the blast furnace operation isn’t affected.
[0040] Also, in the process 200, since the weight ratio of calcined lime fines and iron-bearing fines (catalytic material) are mixed in a weight ratio of 2:1 and in an aspect, the ratio of catalytic material to water in the catalytic slurry is 1:2.5, the coke reactivity index (CRI) of the nut coke is increased by decreasing the starting temperature of solution loss reaction and thereby temperature of thermal reserve zone (TRZ) of blast furnace is decreased considerably.
Analysis of difference in properties of coated and uncoated nut coke
[0041] Table 3 provided below shows the proximate analysis of uncoated and coated nut coke.
Table 3: Proximate analysis of uncoated and coated nut coke
Parameters Ash (%) VM (%) Moisture (%) Fixed Carbon (%)
Uncoated nut coke 16.6 0.92 10.2 82.48
Coated nut coke 17.83 0.97 11.8 81.2

It is observed that slight increase in ash content of coated nut coke over uncoated nut coke is mainly contributed by the doping of lime and iron dust components on the surface of nut coke. Approximately, 1.7% increase in moisture content observed after the coating process of nut coke.
[0042] Table 4 provided below shows the chemical composition of the uncoated and coated nut coke. It can be noted that the new chemical composition of the coated nut coke has a considerable increase in the composition of Fe(T) and CaO which again contributes to increasing in the CRI of the nut coke.
Table 4: Chemical analysis of uncoated and coated nut coke
Constituents (%) Fe(T) CaO SiO2 Al2O3 MgO MnO K2O Na2O P
Uncoated nut coke 1.1 1.4 8.8 4.26 0.26 0.013 0.283 0.125 0.105
Coated nut coke 1.35 2.22 8.68 4.3 0.28 0.01 0.26 0.14 0.108

[0043] FIG. 3 illustrates a graph depicting the starting temperature of solution loss reaction (SLR) for catalyst coated nut coke and uncoated nut coke. The y-axis shows the weight loss (gm) values and the x-axis shows the value of temperature (°C). It is observed from the weight loss curve that almost 50-100°C drop in the starting temperature of the coke gasification reaction is achieved after coating with catalyst on the nut coke surface. This drop-in starting temperature of coke gasification has an influence on reducing the thermal reserve zone (TRZ) temperature of blast furnace. Thus, the reduced temperature of TRZ causes carbon monoxide (CO) to react to a greater extent with an oxygen-containing metal ore in the upper stack of the blast furnace. This increases indirect reduction and reduces the coke requirement for direct reduction at lower parts of the blast furnace, effectively reducing the carbon rate in the blast furnace. This overall improves reduction efficiency of blast furnace.
FIG. 4 illustrates a stats depicting coke reactivity index (CRI), coke strength after reaction (CSR) and moisture content of catalyst coated nut coke and uncoated nut coke. It is observed that CRI of catalyst coated nut coke in comparison with uncoated nut coke is improved by 5% approximately (i.e. CRI from 27 to 32%,) which is mainly due to the catalytic behavior of calcium and iron-based components for coke gasification reaction. It is also observed that approximately 3-4% is drop-in coke strength after reaction (CSR) with carbon dioxide for coated nut coke. Even though moisture content is increased by 1.5 to 2% for the coated nut coke, the net effect on the carbon rate reduction is positive. The impact of increased CRI of the coated nut coke can be seen on various blast furnace parameters as shown in table 5 below. The catalyst coated nut coke produced using the present disclosed system and process is charged into the small blast furnace with a capacity of 1000–1200 tons per day (TPD) hot metal production at the rate of 40-60 kg of coated nut coke per ton of hot metal (THM). The blast furnace parameters were studied for the base period and trial period respectively. It can be observed that the coke rate and production have considerably improved. The benefit of 4-6 kg carbon rate reduction per ton of hot metal is achieved by replacing the normal nut coke with catalyst coated nut coke as shown in Table 5.
Table 5: Impact of increased CRI of catalyst coated nut coke on blast furnace performance
BF Parameters Base Period Trial Period
Sinter rate, (%) 48 51
Pellet rate, (%) 0 0
Oxygen Flow, (Nm3/hr) 13063 12993
HBT, (°C) 1035 1058
Production, (TPD) 1072 1114
Coke rate, (kg/THM) 562 533
Tar rate, (kg/THM) 16 24
Fuel rate, (kg/THM) 574 557
Normalised carbon rate, (kg/THM) 485 480

TECHNICAL ADVANTAGES
[0044] The present disclosure provides a process and a system for production of a catalyst coated nut coke for blast furnace application that provides a considerable increase in the coke reactivity index (CRI) by decreasing the starting temperature of solution loss reaction and hence, reduction in the temperature of the thermal reserve zone (TRZ).
[0045] The present disclosure provides a process and a system for the production of a catalyst coated nut coke that doesn’t increase the cost of the blast furnace operation.
[0046] The present disclosure provides a process and a system for the production of a catalyst coated nut coke that can be practiced commercially.
Equivalents:
[0047] 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 apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be apparent that a single device/article may be used in place of the more than one device or article or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself.
[0048] The specification has described a system and a method for producing catalyst coated nut coke, the process.
[0049] The illustrated steps in the present disclosure are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words "comprising," "having," "containing," and "including," and other similar forms are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
[0050] 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.
LIST OF REFERENCE NUMERALS
100 Slurry preparation tank
102 Feed hopper
104 Water inlet line
104a, 108a, 114a Flowmeter
104b, 104d, 108b, 114b, 114c, 114d, 114e Regulating valves
104c Flush water line
106 Agitator
108 Recirculation line
110 Basket filter
112 Slurry transfer pump
114 Transfer line
116a, 116b Conveyor belts
118 Nut coke hopper
120a, 120b, 120c Nozzles
122a, 122b Compressed air lines

Claims:We claim:
1. A process for producing catalyst coated nut coke, the process comprising:
adding a catalytic material in a slurry preparation tank (100), wherein the catalytic material comprises calcined lime fines and iron-bearing fines in a weight ratio of 2:1;
mixing the catalytic material with water in the slurry preparation tank (100) to form a catalyst slurry;
pumping the catalyst slurry, by a slurry transfer pump (112) installed near a discharge point of the slurry preparation tank (100), through a transfer line (114) from the discharge point to one or more spray headers mounted above different conveyor belts (116a, 116b) transferring nut coke from a nut coke hopper (118) to a wagon which carries the nut coke to blast furnace, each spray headers are provided with respective nozzles (120a, 120b, 120c) to form fine droplets of the catalyst slurry; and
triggering the nozzles (120a, 120b, 120c) to spray the catalyst slurry on the nut coke moving on the conveyor belts (116a, 116b) for producing the catalyst coated nut coke.
2. The process as claimed in claim 1, wherein the calcium bearing fines comprises, by weight, Iron (Fe(T)) 1-2%, Calcium Oxide (Cao) 65-69%, Silicon Dioxide (SiO2) 0.8-1.5%, Aluminum Oxide (Al2O3) 0.2-0.4%, Magnesium Oxide (MgO) 0.6-1.2%, Potassium Oxide (K2O) 0.01-0.03%, Sodium Oxide (Na2O) 0.02-0.03%, Phosphorus Pentoxide (P2O5) 0.01-0.02%, and LOI 25-31%.
3. The process as claimed in claim 1, wherein the iron bearing fines comprises, by weight, Iron (Fe(T)) 25-29%, Calcium Oxide (Cao) 29-35%, Silicon Dioxide (SiO2) 0.7-4.5%, Aluminum Oxide (Al2O3) 0.7-2.0%, Magnesium Oxide (MgO) 2.0-3.0%, Manganese Oxide (MnO) 0.5-0.7%, Potassium Oxide (K2O) 1.0-1.5%, Sodium Oxide (Na2O) 0.15-0.2%, Phosphorus Pentoxide (P2O5) 1.5-2.0 %, and LOI 18-22%.
4. The process as claimed in claim 1, wherein the catalytic material to water ratio maintained in the catalytic slurry is 1:2.5 on a weight basis.
5. The process as claimed in claim 1, further comprising recirculating the catalyst slurry through a recirculation line (108) connected to a water inlet line (104) near the slurry preparation tank inlet.
6. The process as claimed in claim 5, further comprising regulating valve (108b) arranged in the recirculation line (108) so as to control the flow of the catalyst slurry.
7. The process as claimed in claim 1, wherein the slurry preparation tank (100) is made of mild steel coated with fiber-reinforced plastic (FRP) lining.
8. The process as claimed in claim 1, wherein the mixing of the catalytic material with water is performed by an agitator (106) provided in the slurry preparation tank (100), said agitator (106) being operated at a speed range of 50 to 200 revolutions per minute (RPM) using a variable frequency drive (VFD).
9. The process as claimed in claim 1, further comprising blowing compressed air, using compressed air lines (122a, 122b), on the coated nut coke moving on the conveyor belts (116a, 116b) so as to reduce the moisture content of the coated nut coke.
10. The process as claimed in claim 1, wherein the pumping of the catalyst slurry by the slurry transfer pump (112) is performed through a basket filter (110) installed at the discharge point of the slurry preparation tank (100) to prevent coarser particles of the catalyst slurry from entering the slurry transfer pump (112).
11. The process as claimed in claim 1, further comprising controlling of regulating valves (114b, 114c, 114d, 114e) arranged in the transfer line (114) so as to control the flow of the catalyst slurry.
12. A system for producing catalyst coated nut coke, the system comprising:
a slurry preparation tank (100) for preparing a catalyst slurry by mixing a catalytic material and water, wherein the catalytic material composed of calcined lime fines and iron-bearing fines in a weight ratio of 2:1;
a slurry transfer pump (112) installed near a discharge point of the slurry preparation tank (100) to pump the catalyst slurry through a transfer line (114) from the discharge point to one or more spray headers mounted above different conveyor belts (116a, 116b) transferring nut coke from a nut coke hopper (118) to a wagon which carries nut coke to blast furnace; and
nozzles (120a, 120b, 120c) provided at each respective spray headers to form fine droplets of the catalyst slurry, wherein the nozzles (120a, 120b, 120c) are triggered to spray the catalyst slurry on the nut coke moving on the conveyor belts (116a, 116b) for producing the catalyst coated nut coke.
13. The system as claimed in claim 12, wherein the calcium bearing fines comprises, by weight, Iron (Fe(T)) 1-2%, Calcium Oxide (CaO) 65-69 %, Silicon Dioxide (SiO2) 0.8-1.5 %, Aluminum Oxide (Al2O3) 0.2-0.4 %, Magnesium Oxide (MgO) 0.6-1.2%, Potassium Oxide (K2O) 0.01-0.03%, Sodium Oxide (Na2O) 0.02-0.03%, Phosphorus Pentoxide (P2O5) 0.01-0.02%, and LOI 25-31%.
14. The system as claimed in claim 12, wherein the iron bearing fines comprises, by weight, Iron (Fe(T)) 25-29%, Calcium Oxide (CaO) 29-35%, Silicon Dioxide (SiO2) 0.7-4.5%, Aluminum Oxide (Al2O3) 0.7-2.0%, Magnesium Oxide (MgO) 2.0-3.0%, Manganese Oxide (MnO) 0.5-0.7%, Potassium Oxide (K2O) 1.0-1.5%, Sodium Oxide (Na2O) 0.15-0.2%, Phosphorus Pentoxide (P2O5) 1.5-2.0 %, and LOI 18-22%.
15. The system as claimed in claim 1, wherein the catalytic material to water ratio maintained in the catalyst slurry is 1:2.5 on a weight basis.
16. The system as claimed in claim 12, wherein the slurry preparation tank (100) is made of mild steel coated with fiber-reinforced plastic (FRP) lining.
17. The system as claimed in claim 12, further comprising an agitator (106) to mix the catalytic material with water, said agitator (AG) being operated at a speed range of 50 to 200 revolutions per minute (RPM) using a variable frequency drive (VFD).
18. The system as claimed in claim 12, further comprising a recirculation line (108) connected to a water inlet line (104) near the slurry preparation tank inlet of the slurry preparation tank (SPT), so as to recirculate the catalyst slurry using the slurry transfer pump (112).
19. The system as claimed in claim 18, further comprising regulating valve (108b) arranged in the recirculation line (108) so as to control the flow of the catalyst slurry.
20. The system as claimed in claim 12, further comprising compressed air lines (122a, 122b) to blow compressed air on the coated nut coke moving on the conveyor belts (116a, 116b) so as to reduce the moisture content of the coated nut coke.
21. The system as claimed in claim 12, further comprising a basket filter (110) installed at the discharge point of the slurry preparation tank (100) to prevent coarser particles of the catalyst slurry from entering the slurry transfer pump (112).
22. The system as claimed in claim 12, further comprising regulating valves (114b, 114c, 114d, 114e) arranged in the transfer line (114) so as to control the flow of the catalyst slurry.