WO2018142331A1

WO2018142331A1 - System and method for maintaining optimum moisture content in granulated mix

Info

Publication number: WO2018142331A1
Application number: PCT/IB2018/050657
Authority: WO
Inventors: Rakesh KASHYAP
Original assignee: Kashyap Rakesh
Priority date: 2017-02-03
Filing date: 2018-02-02
Publication date: 2018-08-09

Abstract

A method to maintain optimum moisture content in granulated mix comprising; mixing plurality of raw materials with addition of water in nodulizing drum to form granulated mix and loading over pallet car; fixing hot air in terms of pressure before hot air hood, hot air inlet temperature, and initial hot air flow to create constant hot air hood pressure; fixing hot air in hot air wind box for suction pressure, with wind main suction to maintain constant hot air hood pressure and to maintain hot air outlet temperature above dew point temperature; spreading hot air on granulated mix over pallet car before entering ignition furnace, wherein ignition furnace burns top surface layer of granulated mix; sucking hot air on granulated mix through hot air wind box, hot air wind leg, and wind main; and adjusting moisture set point by an auto system/user to either increase or decrease in set point by analysing hot air outlet temperature and hot air hood pressure to reach optimum level in the granulated mix.

Description

"SYSTEM AND METHOD FOR MAINTAINING

OPTIMUM MOISTURE CONTENT IN GRANULATED MIX"

TECHNICAL FIELD

[001] The present disclosure generally relates to a method of producing a sintered ore in a sinter plant.More particularly, the present disclosure relates to the method for maintaining optimum moisture content in a granulated mix.

BACKGROUND

[002] Generally the sintered ore is produced by mixing of several raw material in a nudulizing drum and taken to sinter machine for sintering process. The several raw materials are mixed in a nudulizing drum by adding water to form a granulated mix. The granulated mix is laid down on the sinter pallet car of the sinter machine, and enters the ignition furnace for ignition.Thereby the top surface of the granulated mix is uniformly ignited by burners at a temperature of 1050-1150 °C. The ignited layer lowers down as it is burned with combustion of fuel present inside the granulated mix with air sucked through the sinter bed of granulated mix toward the underside of the pallet car. This way the sintering reaction proceeds gradually from the top surface layer to the lower surface layer of the granulated mix sinter bed.

[003] Conventionally in one method, the method of determining the optimum moisture content in the granulated mix is totally based on the operator's perception. The moisture content of the raw materials is sensed through a moisture sensor and back calculation for moisture addition done by the system for the output moisture content. The operator makes the final decision for the final moisture set point required on the basis of operator experience and by making handmade lump of the granulated mix by feeling the content of the moisture. This method is not so effective and non-continuous.

[004] In second method, an intelligent permeability optimization system is developed for sinter plant. In this system the compressed air is passed through a metering device into the charge mix bunker and a back pressure is developed due to the resistance posted by the charge mix to the air flow. The permeability of the granulated mix is estimated in the charge mix bunker by taking input signals of flow rate of compressed air. The system operator has to set the certain condition for optimum permeability, and any changes with the set condition of sintering process effects the set point of optimum permeability. These methods are not so effective for finding the direction of increase or decrease in moisture set point.In this system change in granulometry of raw material effecting the shift of optimum moisture set point dry or wet side and makes a tough task for the operators for deciding the change in moisture set point. Hence an improvement is required in the sinter plant to maintain optimum moisture content in the granulated mix.

[005] Referring to FIG. 1 (Prior Art) is diagram 100 depicting a sinter machine. The sinter machine 100 comprises, an intermediate bin 102, a drum feeder 104, a loading plate 106, a granulated mix 108, a sinter pallet car 110, a sealing plate 112, an ignition furnace 114, a burner 116, wind boxes 118a-118n, a wind leg 120, a wind main 122, a loading profile sensor 124, a gas line 126, an air line 128 and a thermocouple 130.The sinter machine 100 is configured to provide the sintered ore from the granulated mix 108.The granulated mix 108 taken from the intermediate bin 102 is loaded on the sinter pallet car 110 and enters into the ignition furnace 114. The top surface layer of the granulated mixl08 isignited by the burner 116 at a temperature of 1050-1150 °C.The multiple wind boxesl l8a-118n are present under the sinter pallet car 110. The wind boxes 118a-118n have a suction pressure to suck the process air from the top of the sinter pallet car 110 to the bottom of the sinter pallet car 110. The moisture content of the granulated mix 108 gets evaporated from one layer to another layer with the process air entering from the top of the granulated mix 108. The air entering from the top layer of the granulated mixl08 provides available oxygen for the combustion of fuel in the granulated mix 108 for the sintering process.The various reactions takes place by burning of the fuel present in the layers of granulated mix 108 to form a sintered ore cake. The temperature of the process air is high as the process air passes through the granulated mix 108 after ignition or through the hot sintered ore. The process air absorbs the moisture content from the layers of granulated mix 108. Thereby, the temperature of the process air get drops below the dew point where it re-condenses the absorbed moisture at that available lower layer of granulated mix 108. [006] Due to re-condensation, the initial permeability of the available layer drops down by affecting the total permeability of the granulated mix 108 and finally affects the sintering productivity and quality. The excess moisture content than the optimum level in the granulated mix 108 have the more tendency of re-condensation thereby affecting the sintering process.The lower moisture content than the optimum level in the granulated mix 108 hampers the formation of pseudo-particles and reduce the permeability of granulated mix 108 thereby affecting the sintering process. In both cases, excess and lower moisture content than the optimum level, the permeability of granulated mix 108 affect and hampers the sintering process for the productivity and the uniform heat pattern which affects the quality of the sintered ore.To maintain the optimum moisture content in the granulated mix 108, there is a need to adjust the moisture set point in the system to increase or decrease the moisture content in the granulated mix 108.Therefore, the optimum moisture control is required for a good sintering process.

[007] In the light of aforementioned discussion, there exists a need for a mechanism in footwear that would overcome or ameliorate the above discussed limitations.

SUMMARY

[008] The following presents a simplified summary of the disclosure in order to provide a basic understanding of the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

[009] An objective of the present disclosure is directed towards providing the maximum permeability in a granulated mix with the desired optimum moisture content level helps to improve the productivity and quality of the sintered ore.

[0010] Another objective of the present disclosure is directed towardsa system provides the total control over the variation of the moisture content to work manually or automatically. [0011] Another objective of the present disclosure is directed towards the optimum moisture content in the granulated mix saves some amount of fuel energy in the sintering process and prevents the excess use of moisture in the granulated mix.

[0012] Another objective of the present disclosure is directed towards the maximum utilization of fuel present in the granulated mix helps to produce the sintered ore with uniform heat pattern and improves the quality of sintered ore.

[0013] Another objective of the present disclosure is directed towards the change in the condition represents the permeability and moisture content in the granulated mix and helps to control the required optimum level.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In the following, numerous specific details are set forth to provide a thorough description of various embodiments. Certain embodiments are practiced without these specific details or with some variations in detail. In some instances, certain features are described in less detail so as not to obscure other aspects. The level of detail associated with each of the elements or features should not be construed to qualify the novelty or importance of one feature over the others.

[0015] FIG. 1 is a prior art diagram depictinga sinter machine area where the granulated mix is processed to make a sintered ore.

[0016] FIG. 2 is a diagram depicting a sinter plant area with the raw materials preparation area,raw materials mixing area, a sinter machine area, and the product dispatch section.

[0017] FIG. 3 is a diagram depicting a sinter machine area for operating the sintering process by maintaining optimum moisture content in granulated mix. [0018] FIG. 4 is a diagram depicting the parabolic nature of the permeability curve over moisture content of the granulated mix.

[0019] FIG. 5 is a flow diagram depicting a method for maintaining an optimum moisture content in granulated mix.

[0020] FIG. 6 is a flow diagram depicting a method for obtaining an optimum moisture content in granulated mix.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0021] It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0022] The use of "including", "comprising" or "having" and variations there of herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Further, the use of terms "first", "second", and "third", and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

[0023] Referring to FIG. 2 is an example diagram 200 depicting a system for producing a sintered ore product in a sinter plant. The sinter plant 200 comprises, a raw material preparation area 202, a raw material mixing area 204, a sinter machine area 206, and a sintered ore product dispatch section 208, a ground hopper210, a hammer mill212, a flux screen214, a roll coke crusher 216, coke fines218, flux fines220, a proportioning trolleybins222a-22b, proportioning bins224, weigh feeders226, a nudulizing drum 228, a moisture sensor 229, a hearth layer230, a sinter breaker 232 , a sinter cooler 234, a sinter cool fan 236, a sinter screen 238, and an intermediate bin trolley 240. The raw material preparation area 202 is configured to prepare the raw materials for sintering. The oversized raw materials gets reversed from the flux screen214 to a hammer mill212.The raw material preparation area 202 transmit the raw materials to the proportioning trolley bin 222a after crushing. The proportioning trolley bin 222b is configured to load the different variety of uncrushed raw materials. The raw materials may include but not limited to, iron ore,lime stone,dolomite as flux material,BlastFurnace sinter return,coal,coke and other raw material having sufficient Fe,Cao,Mgo content which can be used economically without effecting the Blast furnace quality and cost. The different raw materials from the proportioning trolley bins 222a-222b are transmitted to the raw material mixing area 204.The raw material mixing area 204is configured to mix the raw materials with the addition of water in a nudulizing drum 228 to form the granulated mix 108(shown in FIG.1). The sinter machine area 206 is configured to receive the granulated mix 108(shown in FIG.l) and prepare the sintered ore. The sintered ore product dispatch section 208 is configured to receive the sintered ore product from the sinter machine area 206.

[0024] Referring to FIG. 3 is a diagram300 depicting one exemplary implementation of a system for maintaining the optimum moisture level in a granulated mix 108. The system 300 comprises, an intermediate bin 102, a drum feeder 104, a loading plate 106, a granulated mix 108, a sinter pallet car 110, a sealing plate 112, an ignition furnace 114, a burner 116, wind boxes 118a-118n, a wind leg 120, a wind main 122, a loading profile 124, a gas line 126, an airline 128 and a thermocouple 130, a hot air wind box 132, a hot air wind leg 134,a temperature regulating valvel36, a variable-voltage/variable-frequency drive fan (VVVFD)138, a hot air inlet temperature(Tl) 140, an initial hot air flow(Fl) 142, a hot air hood pressure(Pm)144, a hot air outlet temperature(T2) 146, a final hot air flow(F2) 148, a pressure regulating valve(PRV) 150, a hot air suction pressure(w)152, a hot air pressure(P) 154,an auto system/userl56, a sinter cooler 158, a hot air container 160, a sinter bed 162, and a hot air hood 164. [0025] The temperature to which air must be cooled to become saturated with water vapor is said to be a dew point. When the air further gets cooled, the airborne water vapor condense to form liquid water (dew).

[0026] The sinter cooler 158 is configured to pro vide the hot air through the hot air container 160 for maintaining the uniform temperature level and dust collection. The hot air is controlled by the variable-voltage/variable-frequency drive fan (VVVFD) 138 for constant hot air pressure (P) 154 and controlling the hot air inlet temperature (Tl) 140 by the inlet temperature regulating valve 136. The hot air is taken from the sinter cooler 158 at a constant temperature of above 200°C to below the ignition point of fuel used in granulated mix 108, such that the hot air outlet temperature (T2) 146 always be above the dew point. The hot air inlet temperature (Tl) 140, the hot air Pressure (P) 154, and the initial hot air flow (Fl) 142 rate is fixed by adjusting the inlet temperature regulating valve 136 and the variable-voltage/variable- frequency drive fan (VVVFD) 138, such that the hot air hood pressure (Pm) 144 is in the range 10-100 millimeter water column (mmwc) and hot air outlet temperature (T2) 146 is above the dew point. The hot air suction pressure (w) 152 is fixed by the pressure regulating valve 150. The hot air suction pressure (w) 152 at hot air wind leg 134is fixed in the range 0 to 200 millimeter water column (mmwc) with the wind main 122 suction pressure of process air under the sinter pallet car 110.

[0027] The auto system/user 156 makes the changes in the set point of moisture content in the granulated mix 108. The subsequent change is observed by the auto system/user 156 until the granulated mix 108 reaches to the optimum moisture set point. The continuous historic readings of parameters guide the auto system/user 156 for controlling the optimum moisture content in the granulated mix 108. The parameters include, but are not limited to be temperature values, pressure values, flow rate, moisture content, and the like. The controlling of optimum moisture content in the granulated mix 108 improve the productivity and quality in the production of sintered ore.

[0028] The loading profile by level sensor 124 of granulated mix 108 is maintained over the sinter pallet car 110. The permeability of the granulated mix 108 is observed over a sinter pallet car 110 by the auto system/user 156. The hot air spread on the granulated mix 108 before entering the ignition furnace 114 by a hot air hood 164. The hot air over the granulated mix 108 is sucked by the hot air wind box 132, the hot air wind leg 134 and the wind main 122 present below the sinter pallet car 110. The hot air on the top surface of granulated mix 108 is fixed in terms of pressure before the hot air pressure (P) 154, the hot air inlet temperature (Tl) 140 and the initial hot air flow (Fl) 142. The hot air inlet temperature (Tl) 140 and the pressure before hot air hood (P) 154 is maintained as desired by the inlet temperature regulating valve 136 and the variable-voltage/variable-frequency drive fan (VVVFD) 138.

[0029] The hot air creates a constant hot air hood pressure (Pm) 144 of range 10-100 millimeter water column (mmwc). Further, the hot air suction pressure (w) 152 also be fixed in one value between the range 0 to 200 millimeter water columns (mmwc) with the wind main 122 available suction pressure, as desired to maintain the hot air hood pressure (Pm) in one value between the range 10 to 100 mmwc. Furthermore, along with these conditions, the hot air outlet temperature (T2) 146 at the hot air wind leg 134is adjusted above the dew point, so that the hot air outlet temperature (T2) 146 does not drop below the dew point with any change in the output set point of moisture content shown in output moisture sensor 229 after nudulizing drum 228(shown in FIG.2). The hot air outlet temperature (T2) 146 at the hot air wind leg 134 is maintained above the dew point. The flow rate of the initial hot air flow (Fl) 142 and the final hot air flow (F2) 148 also be measured.

[0030] The hot air is controlled by the inlet temperature regulating valve 136 for constant temperature as desired on the sinter bed 162 by maintaining the desired hot air hood pressure (Pm) 144.The hot air is passed through the sinter bed 162 to the hot air wind box 132 and there is change in the parameters of hot air outlet temperature (T2) 146 and hot air hood pressure (Pm) 144. The change in parameters of hot air indicates the level of moisture from the optimum level and accordingly desired change in the moisture set point is required to achieve the optimum moisture level in the granulated mix 108.The process air is passed through the wind box 11 Sail 8n.

[0031] The change in the parameters are recorded continuously after setting the initial condition of hot air spreading on the granulated mix 108 through the sinter bed 162. The change in the parameters represent the permeability level and moisture content level and help to control the optimum moisture content in the granulated mix 108 to the required optimum moisture level.

[0032] The loading profile level sensor 124 of the granulated mix 108 is fixed at a required condition. The moisture set point for the granulated mix 108 is adjusted by the auto system/user 156. After few minutes of retention time, the new moisture set point of granulated mix 108 reach the hot air hood 164, which gives some changes in the readings of the hot air outlet temperature (T2) 146 and the hot air hood pressure (Pm) 144. The hot air outlet temperature (T2) 146 get decreased and the hot air hood pressure (Pm) 144 get increased on increasing the moisture set point then the moisture set point is at higher side than the optimum moisture level. Hence, in this situation the auto system/userl56 has to decrease the moisture set point to reach the optimum level. The hot air outlet temperature (T2) 146 get increased and the hot air hood pressure (Pm) 144 get increased on decreasing the moisture set point then the moisture set point is lower side than the optimum moisture level. Hence, in this situation the auto system/user 156 has to increase the moisture set point to reach the optimum level. The auto system/user 156 has the need to observe the parameters of the hot air outlet temperature(T2) 146 and hot air hood pressure (Pm) 144 for finding the level of moisture whether it is on dry or wet side of the optimum level and accordingly the auto system/user 156 make changes to reach the optimum level.

[0033] For example the initial condition of some moisture set point is said to be at (7+x), where the auto system/user can add or reduce the set point by choosing the value of x. Here the value of x is 0. On reducing the value of moisture set point by (7-x), this will create change in hot air hood pressure(Pm) 144and hot air outlet temperature (T2) 146 on reaching of the granulated mix under hot air hood 164. The readings of initial hot air flow (Fl) and final hot air flow (F2) are recorded. Thereby, the auto system /user 156 can operate accordingly to reach the optimum moisture set point on continuous basis.

[0034] Referring to FIG. 4 is a diagram 400a-400b depicting exemplary graph implementation of a permeability over the moisture content of the granulated mix. The permeability over the moisture content of the granulated mix is in a parabolic nature. The graph include the result of obtaining optimum moisture for maximum permeability. The two X and Y axes (right: the permeability, left: the moisture content in %) is on the exponential scale. For example, the relation between the moisture % content and permeability in granulated mix is about 6.8%, it represents the moisture content in the granulated mix is less. For example, the relation between the moisture % content and permeability in granulated mix is about 7.2%, it represents the moisture content in the granulated mix is excess. For example, the relation between the moisture % content and permeability in granulated mix is about 7.0%, it represents the moisture content in the granulated mix is in the optimum level.

[0035] Referring to FIG. 5 illustrates a flow chart 500 depicting a method for maintaining an optimum moisture content in granulated mix, according to some embodiments. As an option, the method 500 is carried out in the context of the details of FIG. 1, FIG. 2, and FIG. 3, however, the method 500 is carried out in any desired environment. Further, the aforementioned definitions are equally applied to the description below.

[0036] The method commences at step 502, the raw materials are mixed with the addition of water in the nodulizing drum to form the granulated mix. The granulated mix is loaded on the sinter pallet car, at step 504. The hot air in terms of pressure before the hot air hood (P), the hot air inlet temperature (Tl), and the initial hot air flow (Fl) is fixed to create the constant hot air hood pressure (Pm),at step 506. The hot air is fixed in the hot air wind box for a hot air suction pressure (w),with wind main suction to maintain the constant hot air hood pressure (Pm) and to maintain hot air outlet temperature (T2) above dew point temperature, at step 508. The hot air spread on the granulated mix before entering the ignition furnace, at step 510. The hot air on the granulated mix is sucked through the hot air wind box, the hot air wind leg, and the wind main, at step 512. The moisture set point is adjusted by an auto system/user to either increase or decrease in the set point by analysing the hot air outlet temperature (T2) and the hot air hood pressure (Pm) to reach the optimum level in the granulated mix, at step 514.

[0037] Referring to FIG. 6 illustrates a flow chart 600 depicting a method for obtaining an optimum moisture content in granulated mix, according to some embodiments. As an option, the method 600 is carried out in the context of the details of FIG. 1, FIG. 2, FIG. 3, and FIG. 4. However, the method 600 is carried out in any desired environment. Further, the aforementioned definitions are equally applied to the description below.

[0038] The method commences at step 602, the hot air is taken from the sinter cooler/source through the hot air container. The hot air is controlled by the variable- voltage/variable-frequency drive fan (vvvfd) for constant hot air pressure (P), at step 604. The hot air inlet temperature (Tl) is controlled by the inlet temperature regulating valve, at step 606. The hot air suction pressure (w) is fixed by the pressure regulating valve (PRV), at step 608. The hot air outlet temperature (T2) is maintained above the dew point such that the hot air outlet temperature (T2) should not come below the dew point after the addition of moisture if required, at step 610. The initial moisture set point is increased or decreased by the auto system/user, at step 612. The decreased value of moisture set point creates change in the hot air hood pressure (Pm) and hot air outlet temperature (T2) on reaching of granulated mix under hot air hood, at step 614. Thereafter, at step 616, the decision is taken by the auto system/user to adjust the moisture set point after change in the parameter of the hot air hood pressure (Pm) and hot air outlet temperature (T2). The auto system/user determines the moisture set point is on higher side or lower side, at step 618. If answer to step 618, is on higher side, then at step 620, decreasing the initial moisture set value if the hot air hood pressure (Pm) decreases and the hot air outlet temperature (T2) increases thereby the auto system/user can reduce the set point until the hot air hood pressure (Pm) increases and the hot air outlet temperature (T2) increases. If answer to step 618, is on lower side, then at step 622, increasing the initial moisture set value if the hot air hood pressure (Pm) decreases and the hot air outlet temperature (T2) decreases thereby the auto system/user can increase the set point until the hot air hood pressure (Pm) increases and the hot air outlet temperature (T2) decreases. The parameters of initial hot air flow (Fl) and final hot air flow (F2) are recorded, at step 624. The value of moisture set point is adjusted by the auto system/user to reach the optimum moisture value, at step 626.

[0039] More illustrative information will now be set forth regarding various optional architectures and uses in which the foregoing method may or may not be implemented, as per the desires of the auto system/user. It should be strongly noted that the following information is set forth for illustrative purposes and should not be construed as limiting in any manner. Any of the following features may be optionally incorporated with or without the exclusion of other features described.

[0040] Although the present disclosure has been described in terms of certain preferred embodiments and illustrations thereof, other embodiments and modifications to preferred embodiments may be possible that are within the principles and spirit of the invention. The above descriptions and figures are therefore to be regarded as illustrative and not restrictive. The present disclosure has been described in terms of straight machine, but there are circular machine existing so this present disclosure may be implemented principally with any other machine without limiting the scope of the invention.

[0041] Thus the scope of the present disclosure is defined by the appended claims and includes both combinations and sub-combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

1. A system for maintaining optimum moisture content in granulated mix comprising: a raw material processing area configured to transmit a plurality of raw materials to multiple proportioning trolley bins; wherein the multiple proportioning trolley bins configured to load plurality of raw materials; a nudulizing drum configured to mix the plurality of raw materials with the addition of water to form a granulated mix; a pallet car configured to load the granulated mix; a hot air hood configured to spread the hot air on the granulated mix over the pallet car; and a hot air wind box, a hot air wind leg, and a wind main configured to suck the hot air from the granulated mix.

2. The system of claim 1, wherein the hot air hood comprises hot air inlet temperature (Tl),hot air Pressure (P), and initial hot air Flow (Fl).

3. The system of claim 1, wherein the hot air is taken by a hot air container for maintaining the uniform temperature level and dust collection.

4. The system of claim 2, wherein the hot air inlet temperature (Tl), the hot air Pressure (P), and the initial hot air Flow (Fl) are fixed at a desired level.

5. The system of claim 1, wherein spreading the hot air on the granulated mix is maintained at a desired set point of pressure, temperature, and flow rate.

6. The system of claim5, wherein the moisture set point is adjusted by auto system/user to either increase or decrease in the set point by analyzing the hot air outlet temperature (T2) and the hot air hood pressure (Pm) to reach the optimum level in the granulated mix.

7. A method to maintain optimum moisture content in granulated mix comprising:

Mixing a plurality of raw materials with the addition of water in the nodulizing drum to form the granulated mix and loading the granulated mix over the pallet car; fixing the hot air in terms of pressure before the hot air pressure (P), the hot air inlet temperature (Tl), and the initial hot air flow (Fl) to create the constant hot air hood pressure (Pm); fixing the hot air in the hot air wind box for suction pressure (w) with wind main suction to maintain the constant hot air hood pressure (Pm) and to maintain hot air outlet temperature (T2) above the dew point temperature; spreading the hot air on the granulated mix over the pallet car before entering the ignition furnace, wherein the ignition furnace burns the top surface layer of the granulated mix; sucking the hot air on the granulated mix through the hot air wind box, the hot air wind leg, and the wind main; and adjusting the moisture set point by anauto system/user to either increase or decrease in set point by analysing the hot air outlet temperature (T2) and the hot air hood pressure (Pm) to reach the optimum level in the granulated mix.

8. A method to obtain optimum moisture content in granulated mix comprising:

Taking the hot air from a sinter cooler through a hot air container;

Controlling the hot air by a variable-voltage/variable-frequency drive fan (VVVFD) for constant hot air pressure (P);

Controlling the hot air inlet temperature (Tl) by an inlet temperature regulating valve;

Fixing the hot air suction pressure (w) by a pressure regulating valve (PRV);

Maintaining the hot air outlet temperature (T2) above the dew point;

Increasing or decreasing the initial moisture set point by a auto system/user; changing the value of moisture set point creates change in the hot air hood pressure (Pm) and hot air outlet temperature (T2) on reaching of granulated mix under hot air hood; taking the decision by the auto system/user to adjust the moisture set point on changing the hot air hood pressure (Pm) and the hot air outlet temperature (T2); decreasing the initial moisture set value if the hot air hood pressure (Pm) decreases and the hot air outlet temperature (T2) increases,whereby the auto system/user enabled to reduce the moisture set point until the hot air hood pressure (Pm) increases and the hot air outlet temperature (T2) increases; increasing the initial moisture set value if the hot air hood pressure (Pm) decreases and the hot air outlet temperature (T2) decreases, whereby the auto system/user can increase the set point until the hot air hood pressure (Pm) increases and the hot air outlet temperature (T2) decreases; recordinga plurality of parameters of the initial hot air flow (Fl) and the final hot air flow(F2); and adjusting the moisture set point to reach the optimum moisture value.