Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A SYSTEM FOR COST EFFECTIVE IRON ORE SINTERING INTENSIFICATION PROCESS INVOLVING COKE OVEN GAS INJECTION.



2 APPLICANT (S)

Name : JSW STEEL LIMITED.

Nationality : An Indian Company incorporated under the Companies Act, 1956.

Address : JSW CENTRE,
BANDRA KURLA COMPLEX,
BANDRA(EAST),
MUMBAI-400051,
MAHARASHTRA,INDIA.



3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to a system for cost effective iron ore sintering intensificationand discloses a method that relates to an exhaust gas circulating apparatuswith injection of coke oven gas(COG)into iron ore sintering process. The method comprises of laying COG pipeline for transportation,designing and fabricating an injection system followed by injecting the COGonto the sinter bed. Firstly, the coke oven gas pipeline is laid from coke oven plant to sinter plant. At the sinter plant the pipeline is divided into two sections, one is to be utilized for top surface ignition of the sinter bed and the second one is connected to the top hood mounted over the sinter bed for waste gas recirculation system. Within the waste gas recirculation hood a series of 3 pipe line with diameter of 80 mm are laid having 16 nozzles to evenly distribute the coke oven gas over the sinter bed. The coke oven gas can replace part of coke to act as a reducing agent, so that the fuel ratio and sintering cost are reduced, with an improvement in overall sintering properties. Through this invention the problems of energy waste and environmental pollution caused by combustion of the coke oven gas are avoided and a demonstration for utilization of coke oven gas. By using this method, when the coke oven gas is injected from the recirculating hood at a flow of 100 Nm3/hr and a pressure of 10 mbar shows an improvement of cumulative +10 mm yield by 7.2 %, reducing cumulative -5 mm by 1.6 %, with an increase in tumbler strength by 1 %, increasing the mean sinter size by 3.33 mm and an overall reduction in coke rate by 2.5 kg for every one ton of sinter produced.
BACKGROUND OF THE INVENTION
In integrated iron and steel operations, the iron-making process constitutes approximately 70% of total energy usage, with the sintering process accounting for 10 -20%. Unfortunately, this process also generates significant environmental pollutants like CO2, SOx, and NOx. Thus, it is imperative for steel companies to reduce solid fuel consumption and mitigate emissions. The sintering process involves combining iron ores, additives (e.g., limestone, dolomite, burned lime), and fuels (e.g., coke breeze, coal) in a rotary drum, followed by agglomeration with water to achieve uniform particle size. Sintering occurs under an ignition hood, with blowers drawing gas through the sinter bed, while the final product is crushed, cooled, and sifted into three fractions. Gas collection beneath the sinter strand varies in volume, composition, and temperature.
Beneath the sinter strand, wind boxes gather the varying gas stream, with a relatively high specific flow rate (1500-2500 Nm3/ T of sinter) containing hazardous substances like dust, CO2, SOx, NOx, and dioxin. Traditional end-of-pipe cleaning methods are costly and result in low by-product utilization. Flue gas recirculation (FGR) partially recycles waste gas through the hot sinter and flame front.
The current issues of iron ore sintering process are how to reduce solid fuel consumption and to maintain proper quality of sinter. In the conventional sintering bed, the combustion of solid fuel supplies the heat required for sintering while it generates uneven distribution of heat in the bed due to the effect of heat accumulation, i.e., the heat is insufficient in upper layer and excessive in lower layer. Insufficient heat will result in under-melted sinter and more return fine, while excessive heat will result in low sinter reducibility (Fan et al. 2021; Nakano and Okazaki 2011). Therefore, it is considered that the uneven heat distribution of sintering bed is an important factor affecting the quality of sinter.
Selective waste gas recirculation (SWGR) is a technique complements sintering to reduce energy use, waste gas, and SO2 emissions. SWGR directing single wind box gas to the sinter conveyor hood effectively lowers fuel consumption, emissions, and gas volume.
A circulation system for the exhaust gas of the sintering machine and use of its sensible heat to reduce the cooling rate has been reported, but on the other hand, it was also reported that productivity will decrease if the recirculated exhaust gas has a low O2 concentration and high moisture content. It was pointed the sinter productivity decrease with the lower O2 concentration and higher humidity in the main exhaust gas.
Thus in order to enhance the proper utilization of flue gas and reduce the solid fuel consumption at sinter plant additional gaseous fuel in the form of coke oven gas along with the flue gas has been developed. The present invention relates to a flue gas circulating iron ore sintering apparatus using coke oven gas, in particular to the use of coke oven gas to reduce the use of coke along with the improvement in sintering process parameters and sinter properties. The present invention relates to an exhaust gas circulating iron ore sintering apparatus along with COG injection.

Prior art search
The research initially started from Japan, when Nobuyuki oyama et al. (ISIJ International Vol. 51, No. 6, 2011) injected CH4-rich LNG (Liquid natural gas) into the sintering bed. Better sinter quality and lower solid fuel consumption were reached, with 60,000 ton CO2 reduction annually. Similar results were also found by the Cheng Z.L. et al.(Applied Energy, Vol. 207, 2017) from China, where pure methane was used as injection gas in their investigation.
Taking the availability and cost of gas fuels, J Castro et al. (Journal of Materials Research and Technology, Vol. 2, No. 4, 2013) (Institute of Materials, Minerals and Mining, Ironmaking and Steelmaking, Vol. 39, No. 8)from Brazil investigated the influences of steelworks gaseous fuels such as H2-rich COG, mixture of COG and blast furnace gas on sintering performance through a comprehensive multiphase mathematical simulation model, which verified the injection feasibility of these gases. The broadening of the combustion zone was indicated. The studies suggested a decrease in the solid fuel by 5.8 kg per ton of sinter when replacing 2% of the recirculating flue gas with a mixture of COG and BF gas. In his study, J Castro et al. (Journal of Cleaner Production, Vol. 198, 2018) also suggested the use of Biogas injection as an alternative fuel for sintering process showed the possibility of renewable fuel as a replacement for fossil fuel. All the research results by J Castro et al. mainly focused on revealing the influencing of gas injection through mathematic model, with few laboratory tests conducted.However, the actual measurements were not available in his research.
Guilherme et al. (Rem Magazine School of Mines, Vol. 65, No. 3, 2012) developed a stimulation model to evaluate the impact of injecting COG upto 10 % of suction volume on the sintering process. The simulation results indicate a lower consumption of solid fuel with the injection of COG and an increase of the combustion front. As a result, this increased the fraction of calcium silicates, which consequently improved the reducibility and also reduced the amount of CO2 in the output gas.
Acharyulu et al. (Journal of Sustainable Metallurgy, Vol. 7, 2021)tried the injection of Fuel gases such as coke oven gas (COG) and liquefied petroleum gas (LPG) through a lab scale sinter pot, to see the effect on sintering speed and quality parameters. Densification was predominant in the case of COG and LPG, leading to an increase in both cold and hot strength. Acceleration of the sintering process was noticed when oxygen was injected. Superior quality parameters and higher productivity were achieved with combined COG and oxygen injection. A reduction of solid fuel consumption coupled with a reduction in CO2 emissions is achieved. Apart from achieving superior quality parameters, injection of COG and oxygen is envisaged to reduce 10 kg of solid fuel, amounting up to 0.05 ton reduction in CO2 emissions per ton of sinter (5%).
Wenjie Ni et al. (International Journal of Chemical Reactor Engineering, Vol. 20, No. 10, 2022) developed a mathematical model is developed and numerical simulations of iron ore sintering process with coke oven gas (COG) injection and oxygen enrichment. The predicted an increase in sinter yield by 44.5%, with an increase in NOx emission by 8.3%. Modelling was an efficient measure to investigate the influence of gas injection on sintering performance, while might ignore some important information of the practical process. Moreover, the practical sintering process is fluctuant and unstable, relying on numerical modelling only was hard to clearly reveal the influence of coke oven gas on sintering performance.
Iwami Y et al. (ISIJ International, Vol. 55, No. 11, 2015)reported that both sinter cold strength and productivity have increased when LNG and oxygen are injected into the sinter bed. The possibility of holding the sintering bed at 1473 K - 1673 K for an extended time by combined gaseous fuel and oxygen injection was confirmed in an actual sintering plant. Up to the oxygen concentration of 27 vol %, the holding time at 1473 K - 1673 K was extended as the oxygen concentration increased. Similar study was carried out by H. Kagn et al. (ISIJ International, Vol. 51, No. 7, 2011) using a lab scale sinter pot setup injecting oxygen during the sintering process. The enrichment of oxygen concentration in the induced air provided effective heat utilization with a faster coke fuel combustion and higher temperature during sintering process.
Ishimitsu Aet al (Tetsu-to-Hagane, Vol. 48, No. 11, 1962),proposed preheated air injection method but the application of that technique is reportedly limited, as the preheated air does not affect combustion of coke breeze. It is difficult to control the temperature zone over 1200°C, because the preheating air temperature was low between 150°C and 450°C. It also deteriorated the permeability with the increase in actual velocity.
Looking at the previous researches, it is found that the focus was mainly on gas fuel injection studies through numerical models or through lab scale studies and was mainly focused on the energy saving and emission reduction through gaseous fuel injection, while the process mechanism and influence of injection parameters have not been studied in detail, particularly for product quality and production yield. The present invention proposes a method to inject COG through the waste gas recirculation system during the sintering process at plant scale. The advantages include improved process parameters, higher sinter quality, and fuel savings. This method aims to enhance the sintering process parameters and improve the quality of the sintered product.
OBJECTS OF THE INVENTION
The present invention relates to a system for cost effective iron ore sintering intensification with co-operative flue gas circulating apparatus using COG and a method thereof, in particular to utilize the COG so that it can replace part of coke to act as a reducing agent during the sintering process so that the amount of solid fuel utilized for the sintering process can be reduced.
A further objective of the invention is to improve the quality of sinter through an improved combustion efficiency of the sinter with increase in combustion zone thickness to enhance the residual time for sinter above 1200 °C.
Another objective is to improve the heat utilization and sinter strength leading to reduction in overall fine generation.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to a system for cost effective iron ore sintering intensification comprising:
sintering machine including bogie to carry charged raw sinter mix material from a hopper means , wind box installed in the lower portion of the sintering machine bogies to suck the air required for the sintering reaction under controlled flame generation in an ignition furnace;

waste gas recirculation means including a main exhaust pipe from which a portion of exhaust/flue gas from sinter machine is recirculated and discharged on the top of sinter bed through a recirculation hood installed at the rear end of the ignition furnace over the sintering machine bogie in the traveling direction of the sintering bogie;

coke oven gas(COG) pipeline operatively to sinter plant for transporting of COG to sinter machine for desired intensification of the sintering process therein;

said COG pipeline divided into two sections at the sinter plant, whereby one is supplied for top surface ignition of the sinter bed and the other one is operatively connected to the top recirculation hood mounted over the sinter bed for waste gas recirculation system;

said COG pipeline supplying to the top surface ignition of sinter bed including injection means comprising of a plurality of gas inlet pipes with nozzles selectively disposed inside said recirculation hood for injecting coke oven gas(COG) into an upper layer of the sintering compounding material carried on said sintering bogie, said coke oven gas injection pipes installed in the longitudinal direction of the sintering machine bogie at the rear end of the ignition furnace, favouring reduced solid fuel consumption and improved sinter quality and yield.

A further aspect of the present invention is directed to said system where said coke oven gas injection means comprising a main COG pipe line distributed into three separate pipe lines, each of said three pipe lines comprises 16 nozzles (holes) evenly distributed along an 80mm diameter pipe and said pipes are positioned at an approximate gap of 800mm from each other, collectively facilitating precise gas distribution and control for enhanced operational efficiency of sintering.

A still further aspect of the present invention is directed to said system which is adapted for injection of COG at a flow rate of 100 nm3/hr and at a pressure of 10 mbar into the air drawn from the sinter bed through the wind box located below sinter bed via the wind box main.

A still further aspect of the present invention is directed to a method for intensifying iron ore sintering for cost effective control of quality and productivity involving the system as described above comprising injection of Coke oven Gas(COG) through waste gas recirculation hood comprising

recirculating the sintering plant waste gas from main exhaust pipe from which atleast a portion of exhaust/flue gas from sinter machine is recirculated and discharged on the top of sinter bed through a recirculation hood installed at the rear end of the ignition furnace over the sintering machine bogie in the traveling direction of the sintering bogie;

operatively connecting coke oven gas(COG) pipeline to sinter plant for transporting of COG to sinter machine for desired intensification of the sintering process therein;

said COG pipeline supplying COG divided into two sections at the sinter plant, whereby one supply is to the top surface ignition of the sinter bed and the other supply is operatively connected to the top recirculation hood mounted over the sinter bed for waste gas recirculation system;

said COG supply to the top surface ignition of sinter bed through injection means comprising of a plurality of gas inlet pipes with nozzles selectively disposed inside said recirculation hood for injecting coke oven gas(COG) into an upper layer of the sintering compounding material carried on said sintering bogie, said supply through said coke oven gas injection pipes carried out in the longitudinal direction of the sintering machine bogie at the rear end of the ignition furnace, favouring reduced solid fuel consumption and improved sinter quality and yield.

A still further aspect of the present invention is directed to said method involving injection of Coke oven Gas(COG) through waste gas recirculation hood comprising
charging raw sinter mix material on sinter bogie through hopper , said sinter bogie with sinter bed on it travelling at desired speed;
Initiating ignition of sinter bed top surface through ignition furnace;
Sucking air at desired rate through wind box placed below the sinter bogie to propagate flame front from top to bottom through sinter bed height;
recirculating a portion of exhaust/flue gas from sinter machine and discharging on the top of sinter bed through a recirculation hood installed at the rear end of the ignition furnace over the sintering machine bogie in the traveling direction of the sintering bogie;
injecting coke oven gas(COG) into an upper layer of the sintering compounding material carried on said sintering bogie through a plurality of pipes with nozzles selectively disposed inside said recirculation hood installed in the longitudinal direction of the sintering machine bogie at the rear end of the ignition furnace as the sinter bed continuously moves under said COG pipe lines via the sinter bogie/pallet car, to reduce solid fuel consumption and improve sinter quality and yield.

Another aspect of the present invention is directed to said method wherein said COG is injected at a flow rate of 100 nm3/hr and at a pressure of 10 mbar into the air drawn from the sinter bed through the wind box located below sinter bed via the wind box main.

Yet another aspect of the present invention is directed to said method wherein exhaust gas circulation along with the injection of COG favour extending the high-temperature zone and promote the formation of the liquid phase and when the injected COG reaches the high temperature zone above the combustion layer, the combustion reaction occurs, which can provide a new high temperature zone, slow down the sinter cooling speed, extend the holding time of sinter at high temperature zone, and thereby improves the sintering process by correspondingly reducing the proportion of solid fuel such as coke or coal being utilized for the sintering process, which is also conducive to improving the reducibility of sinter and reducing the environmental pollution.

A still further aspect of the present invention is directed to method said enabling increase in cumulative +10 mm sinter yield by 7.17% to reach 72.38%, while sinter fines (-5 mm) have decreased by 1.55% to 5.55%, and led to a notable reduction in coke consumption by 2.50 kg per ton of sinter produced, improving the tumbler strength of the sinter particles (+6.3 mm) from 74.67% in the conventional method to 75.67% , increase in the mean particle size of the sinter by 3.33 mm, going from 16.19 mm to 19.52 mm.

Above and other aspects and advantages of the present invention are described hereunder in greater details with reference to the following accompanying non limiting illustrative drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1: shows a layout of the sintering process set up.
Figure 2: shows the details of COG injection setup in sintering apparatus of present invention.

DETAILED DISCRIPTION OF THE INVENTION WITH REFERENCE TO ACCOMPANYING DRAWINGS
According to the present invention for achieving the above object, the sintering machine bogie to charge the raw material in the hopper, the wind box installed in the lower portion of the sintering machine bogie to suck the air required for the sintering reaction. In the exhaust gas circulation type iron ore sintering apparatus comprising a main exhaust pipe sent to the electric dust collector, after the electric dust collector a portion of the flue gas is sent to the chimney whereas a portion of the flue gas is sent back to the sintering process through a waste gas recirculation hood. A COG injection point is connected to the recirculation hood provided with a COG distribution pipeline. An exhaust gas circulating iron ore sintering apparatus using COG injection system is provided.
Through the current invention COG gas is injected to an amount of 100 Nm3/hr at a pressure of 10 mbar into the air drawn from the sintered bed using the gas recirculating system. A flue gas circulating iron ore sintering method using COG is provided.
In the conventional sintering process, the cumulative +10 mm sinter yield is 64.21%, and sinter fines (-5 mm) account for 7.10% of the output. Additionally, the coke consumption in this process is 58 kg per ton of sinter produced.
In contrast, the sintering method introduced by our present invention has yielded significant improvements. The cumulative +10 mm sinter yield has increased by 7.17% to reach 72.38%, while sinter fines (-5 mm) have decreased by 1.55% to 5.55%. Moreover, this innovation has led to a notable reduction in coke consumption by 2.50 kg per ton of sinter produced.
Regarding the tumbler strength of the sinter particles (+6.3 mm), it has improved from 74.67% in the conventional method to 75.67% with the use of our invention. Additionally, the mean particle size of the sinter has increased by 3.33 mm, going from 16.19 mm to 19.52 mm thanks to this innovative approach.
In general, in the sintering plant, as shown in Figure 1, sintered raw materials including various iron ores and secondary raw materialsand powdered coke are mixed and charged into the sintered raw material hopper 1 of the iron ore sintering machine. The raw material is charged to the sintering machine trolley 2 via the inclined plate 3 by the rotation of the drum feeder 4 over a bottom layer of coarse feed which is first laid on the sintering machine trolley 2 through the hopper 5.
Subsequently, the surface of the sintered raw material is ignited in the ignition furnace 6 and passed through an annealing hood 7, and a sintering reaction in which coke isburned in the sintered raw mix layer 2 under the suction of air is performed. The air is sucked downward from the wind boxes 8is collected in the electric dust collector 10through a main exhaust pipe wind main 9by the waste gasfan11. An agglomerated product of iron ores, fluxes, and coke is thus produced as a result of continuous suction and movement of flame front down the bed. A portion of the flue gas coming from the waste gas fan 11is sent to the chimney 13 through dampers 12.
The exhaust gas generated in the sintering machine is maintained at about 100 °C or less in the first half in the longitudinal direction of the sintering machine, and high temperature exhaust gas of up to 500 ° C. is generated in the second half on an average. The temperature of the gas discharged from the chimney 13 is about 150-200 °C. Using the waste gas recirculation system a portion of waste gas coming from the waste gas fan along with a portion of atmosphere air 15 is circulated back to the top sinter machine trolley using a WGR fan 14 via a WGR duct 16 to the WGR hood 17.
In particular, a flue gas recycle sintering method that can significantly reduce the amount of sinter waste gas discharged by recycling the sintering machine flue gas has been in the spotlight. That is, in view of the fact that the exhaust gas recycle sintering method for recovering sensible heat of sintered flue gas reduces the total emission of sintered flue gas, many studies have been published or patented in the past decade for preventing environmental pollution.
The operation of sintering by circulating the exhaust gas as described above has the following problems:
With the waste gas recovery system in order to achieve an effective sintering process it is necessary to extend the length of the sintering machine and reduce the layer thickness.
Second, in the structure that covers the entire sintering machine with a hood, the exhaust gas flowing through the main exhaust pipe is reduced to almost 50%, and the total amount of SOx and NOx generation is also reduced, but the oxygen concentration is lowered. Due to reduce oxygen concentration within the flue gases, it can result in incomplete combustion of solid fuel during the sintering process.
Third, the presence of enclosed hood over the sinter bed can reduce intake of fresh air which can result in incomplete combustion. When an enclosed hood is placed over the sinter bed in an iron ore sintering process, it serves as a physical barrier that can restrict the intake of fresh air into the sintering zone.The presence of fresh air, is crucial for the combustion of fuel sources, including coke breeze and other carbonaceous materials used in the sinter mix
Forth, incomplete combustion can lead to the release of unburned fuel components, such as carbon monoxide (CO) and hydrocarbons, into the waste gases. These compounds are considered pollutants and can have environmental and regulatory implications.
The present invention has been made to solve the above-mentioned problems of the prior art.Through the present invention COG is injected over the top surface of the sintering mix through a series of COG pipe line 18 (Figure 1) setup strategically installed over WB5. The exhaust gas circulation along with the injection ofCOGinjection can help in extending the high-temperature zone and helping to promote the formation of the liquid phase. When the injected COG reaches the high temperature zone above the combustion layer, the combustion reaction occurs, which can provide a new high temperature zone, slow down the sinter cooling speed, extend the holding time of sinter at high temperature zone, and therefore improves the sintering process. This can help in correspond reduce the proportion of solid fuel being utilized for the sintering process, which is also conducive to improving the reducibility of sinter and reducing the environmental pollution.
Hereinafter, this invention is demonstrated in detail along with accompanying drawing.
Figure 2 shows the detailed drawing showing the COG injection pipe line setup over the sinter bed. A COG pipe line setup has been installed over the sinter bed 1 inside the WGR hood 2. The sinter bed continuously moves under the COG pipe line via the sinter pellet car 3. The COG injection setup consist of a main COG pipe line 4 distributed into three separate pipe lines 5, each with 16 nozzles (holes) evenly distributed along an 80mm diameter pipe. These pipes 5are positioned at an approximate gap of 800mm from each other, collectively facilitating precise gas distribution and control for enhanced operational efficiency in the designated industrial process. The injection of COG amount to a flow rate of 100 nm3/hr at a pressure of 10 mbar into the air drawn from the sinter bed 1through the wind box 6 via the wind box main 7.
Hereinafter, the present invention will be described through Comparative examples:
Prior to applying the present invention to the plant operation, sintering process is carried out using a waste gas reticulation system without injection of COG gas.
The raw material for sintering including iron ore, Return fines, coke breeze, fluxes and other secondary raw materials is charged to the sintering machine bogie 2 through a charging hopper 1, and the sintering process is performed under a WGR hood 17. (See figure 1). Table 1 shows the input raw material composition ratio utilized for sinter production.
Table 1:Sinter green mix (blend)
Raw Material Weight %
Iron Ore 63.63
Limestone 6.88
Dolomite 5.35
Sinter Return fines 15.31
Steel Waste 8.83
Prior to applying the present invention to the sintering process is carried out through the conventional process involving WGRwithout the injection of COG gas. The solid fuel requirement for the sinter production through the conventional process stands at 58 kg/t of sinter produced.
Through the present invention a series of pipe lines has been strategically installed above WB5, consisting of three separate pipe lines, each with 16 nozzles (holes) evenly distributed along an 80mm diameter pipe. These pipes are positioned at an approximate gap of 800mm from each other are installed inside the WGR hood 17 to inject COG gas at flow rate of 100 nm3/hr at a pressure of 10 mbar. For the current invention the solid fuel requirement for the sinter production have dropped to 55.5 kg/t of sinter produced. (See Figure 1).Table 2 shows sintering process parameters and physical properties of the sinter produced with and without the COG injection.
Table 2: Sintering process parameters and Sinter properties
Parameter Units Test :1 (Without COG injection) Test :1 (With COG injection)
Coke Consumption kg/t of sinter produced 58 55.50
Mean Particle size (MPS, mm) mm 16.19 19.52
Sinter Product Yield (+10 mm) % 65.21 72.38
Sinter fine Generation (-5 mm) % 7.10 5.55
Tumbler Strength (TI, +6.3 mm) % 74.67 75.67
Abrasive Index (AI, -0.5 mm) % 4.80 4.73

As shown in Table 2, in the conventional sintering method, the sinter yield of cumulative +10 mm is 64.21 % and the sinter fine generation (-5 mm) is 7.10 %. Also the coke consumption for the conventional process stands at 58 kg/t of sinter produced.

In the sintering method using the present invention, the sinter yield of cumulative +10 mm has increased by 7.17 % to 72.38 %, the sinter fine generation (-5 mm) is reduced by 1.55 % down to 5.55 %. Through the current invention there is drop in coke consumption by 2.50 kg/t of sinter produced.
For the conventional sintering method, the tumbler strength (+6.3 mm) of the sinter stands at 74.67 %, which is increased by 1 % to 75.67 % through the current invention. The mean particle size for the sinter produced has increased by 3.33 mm from 16.19 to 19.52 mm through the current invention.
, Claims:We Claim:
1. A system for cost effective iron ore sintering intensification comprising:
sintering machine including bogie to carry charged raw sinter mix material from a hopper means , wind box installed in the lower portion of the sintering machine bogies to suck the air required for the sintering reaction under controlled flame generation in an ignition furnace;

waste gas recirculation means including a main exhaust pipe from which a portion of exhaust/flue gas from sinter machine is recirculated and discharged on the top of sinter bed through a recirculation hood installed at the rear end of the ignition furnace over the sintering machine bogie in the traveling direction of the sintering bogie;

coke oven gas(COG) pipeline operatively to sinter plant for transporting of COG to sinter machine for desired intensification of the sintering process therein;

said COG pipeline divided into two sections at the sinter plant, whereby one is supplied for top surface ignition of the sinter bed and the other one is operatively connected to the top recirculation hood mounted over the sinter bed for waste gas recirculation system;

said COG pipeline supplying to the top surface ignition of sinter bed including injection means comprising of a plurality of gas inlet pipes with nozzles selectively disposed inside said recirculation hood for injecting coke oven gas(COG) into an upper layer of the sintering compounding material carried on said sintering bogie, said coke oven gas injection pipes installed in the longitudinal direction of the sintering machine bogie at the rear end of the ignition furnace, favouring reduced solid fuel consumption and improved sinter quality and yield.

2. The system as claimed in claim 1 where said coke oven gas injection means comprising a main COG pipe line distributed into three separate pipe lines, each of said three pipe lines comprises 16 nozzles (holes) evenly distributed along an 80mm diameter pipe and said pipes are positioned at an approximate gap of 800mm from each other, collectively facilitating precise gas distribution and control for enhanced operational efficiency of sintering.

3. The system as claimed in anyone of claims 1 or 2 which is adapted for injection of COG at a flow rate of 100 nm3/hr and at a pressure of 10 mbar into the air drawn from the sinter bed through the wind box located below sinter bed via the wind box main.

4. A method for intensifying iron ore sintering for cost effective control of quality and productivity involving the system as claimed in anyone of claims 1 to 3 comprising injection of Coke oven Gas(COG) through waste gas recirculation hood comprisingrecirculating the sintering plant waste gas from main exhaust pipe from which atleast a portion of exhaust/flue gas from sinter machine is recirculated and discharged on the top of sinter bed through a recirculation hood installed at the rear end of the ignition furnace over the sintering machine bogie in the traveling direction of the sintering bogie;

operatively connecting coke oven gas(COG) pipeline to sinter plant for transporting of COG to sinter machine for desired intensification of the sintering process therein;

said COG pipeline supplying COG divided into two sections at the sinter plant, whereby one supply is to the top surface ignition of the sinter bed and the other supply is operatively connected to the top recirculation hood mounted over the sinter bed for waste gas recirculation system;

said COG supply to the top surface ignition of sinter bed through injection means comprising of a plurality of gas inlet pipes with nozzles selectively disposed inside said recirculation hood for injecting coke oven gas(COG) into an upper layer of the sintering compounding material carried on said sintering bogie, said supply through said coke oven gas injection pipes carried out in the longitudinal direction of the sintering machine bogie at the rear end of the ignition furnace, favouring reduced solid fuel consumption and improved sinter quality and yield.

5. The method as claimed in claim 4 involving injection of Coke oven Gas(COG) through waste gas recirculation hood comprisingcharging raw sinter mix material on sinter bogie through hopper , said sinter bogie with sinter bed on it travelling at desired speed;
Initiating ignition of sinter bed top surface through ignition furnace;
Sucking air at desired rate through wind box placed below the sinter bogie to propagate flame front from top to bottom through sinter bed height;
recirculating a portion of exhaust/flue gas from sinter machine and discharging on the top of sinter bed through a recirculation hood installed at the rear end of the ignition furnace over the sintering machine bogie in the traveling direction of the sintering bogie;
injecting coke oven gas(COG) into an upper layer of the sintering compounding material carried on said sintering bogie through a plurality of pipes with nozzles selectively disposed inside said recirculation hood installed in the longitudinal direction of the sintering machine bogie at the rear end of the ignition furnace as the sinter bed continuously moves under said COG pipe lines via the sinter bogie/pallet car, to reduce solid fuel consumption and improve sinter quality and yield.

6. The method as claimed in claim 4 or 5 wherein said COG is injected at a flow rate of 100 nm3/hr and at a pressure of 10 mbar into the air drawn from the sinter bed through the wind box located below sinter bed via the wind box main.

7. The method as claimed in anyone of claims 4 to 6 wherein exhaust gas circulation along with the injection of COG favour extending the high-temperature zone and promote the formation of the liquid phase and when the injected COG reaches the high temperature zone above the combustion layer, the combustion reaction occurs, which can provide a new high temperature zone, slow down the sinter cooling speed, extend the holding time of sinter at high temperature zone, and thereby improves the sintering process by correspondingly reducing the proportion of solid fuel such as coke or coal being utilized for the sintering process, which is also conducive to improving the reducibility of sinter and reducing the environmental pollution.

8. The method as claimed in anyone of claims 4 to 7 enabling increase in cumulative +10 mm sinter yield by 7.17% to reach 72.38%, while sinter fines (-5 mm) have decreased by 1.55% to 5.55%, and led to a notable reduction in coke consumption by 2.50 kg per ton of sinter produced, improving the tumbler strength of the sinter particles (+6.3 mm) from 74.67% in the conventional method to 75.67% , increase in the mean particle size of the sinter by 3.33 mm, going from 16.19 mm to 19.52 mm.

Dated this the 1st day of December, 2023
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)
IN/PA-199