FIELD OF INVENTION
This invention in general relates to a method of cooling incandescent metallurgical coke produced in coke oven batteries by way of improvements in the design of quenching / cooling to enhance the value of resulting coke and if desired recovery of heat extracted for generation of steam / power. More particularly the present invention relates to a method of cooling incandescent metallurgical coke.
DESCRIPTION OF RELATED ART
Metallurgical Coke is the essential raw material for production of liquid iron in blast furnaces. Other applications are found in iron foundry, ferroalloy, soda ash industry, zinc & lead producers and in smaller quantities in the cement industry, gas producers, pit furnaces for small castings and domestic purposes and more recently, to a limited extent, in COREX units for producing iron.
Metallurgical coke is produced from specific blends of coking coal in coke oven batteries. Coke oven batteries can be of two types:
(1) Conventional By-Product Recovery Type; and
(2) Non Recovery Type (Heat Recovery Type).
Both types of batteries produce hot coke of approx 1100° C temperatures which is pushed into a hot coke car and then moved into a cooling chamber where it is cooled prior to transport and use.
Cooling of hot coke is presently being done by two methods:
Wet quenching by water
Coke Dry Quenching (CDQ) process
The wet quenching by water rapidly cools the hot coke. Wet quenching is the most common practice in several installations around the globe and varies in level of

mechanization and water recycling only. The time for quenching can range from 4 to 8 minutes and typically produces coke with total moisture of around 8 to 18%. The steam produced during the quenching process is generally vented to the atmosphere.
In the coke dry quenching process, coke produced from the coke oven battery is subject to slow cooling by an inert gas. This has the advantage of significantly lowering total moisture in coke (to approx.2-3%) and thereby enhancing the value of the resulting coke. In addition, the heat from the cooling is recovered and converted to steam or power, thereby generating additional revenue. Due to the high capital investment required for this technology, only coke oven batteries in some large integrated steel plants have opted for this process
The US Patent No. 3,959,084 titled "Process for cooling of coke" describes a method of cooling the coke wherein the incandescent coke produced in coke oven batteries is cooled by first using inert gas and subsequently by water. As a result the final coke will contain about 2-3% moisture. The patent further describes cooling method wherein upon discharge from a coke oven, highly heated coke is cooled by charging the hot coke to a shaft cooler wherein it is contacted with an inert cooling gas to a temperature of between 600.degree.-800 degree F(315 deg C- 426 deg C), the coke then being discharged through a pressure retention device and to a quench bunker by means of a feeding device, With the coke further cooled to a temperature of below 300 degree F(148 degC) by water sprays, while preventing entrance of steam into the shaft cooler. The feed means and quench bunker are enclosed so as to prevent discharge to the atmosphere of steam produced on contact of the water spray with the coke as well as particulate material carried thereby. The coke at below 300 degree F(148 deg C) is then fed to a conveyor for removal from the cooling area.
In the above patent, the consumption of inert gas is expected to be large, hence economically the process is not viable. Moreover, it is unlikely that coke moisture

up to 2-3% can be achieved by this process. There are no known commercial installations based on this process to prove otherwise.
SUMMARY OF THE INVENTION
The primary object of the present invention is to develop and implement a low cost, environment friendly, safe & energy efficient method for cooling coke by using optimal quantity of water and inert gas and to manufacture premium grade metallurgical coke having low moisture content while recovering the heat for steam or power generation. Use of optimal quantity of water prior to dry cooling with inert gas greatly reduces the quantity of inert gas required and total time for the cooling while ensuring low coke inherent moisture.
It is another object of the invention to provide a low cost method for minimizing coke total moisture thereby increasing the value of coke in terms of less coke required per ton of hot metal produced in blast furnaces.
It is another object of the invention to provide a method for cooling coke which results in negligible air or water pollution.
It is yet another object of the invention to provide a method for cooling coke which allows significant energy recovery which was otherwise being lost to the atmosphere.
It is yet another object of the invention to provide a method for cooling coke which utilizes minimal mechanization by leveraging gravity forces and existing suction and heat recovery system wherever possible thereby minimizing capital investment.
It is yet another object of the invention to provide a method for cooling coke which is much faster than the conventional dry quenching plants providing the benefit that a relatively small unit consuming less inert gas can meet the desired cycle

times of large coke plants. This ensures significantly lower specific investment as compared to conventional dry quenching plants.
It is yet another object of the invention to provide a method for cooling coke which allows for flexibility in operation through simple coordinated controls that can be adjusted based on coal blends that are used that could result
> in varying coke bulk density among other properties,
> in any necessary adjustments required, if certain portions of the coke oven battery system are under repair,
> in provisions for venting the hot inert gases safely into the atmosphere during statutory shutdowns or failures of the coke oven plants and /or steam / power generation units.
It is yet another object of the Invention to provide a method for cooling coke which utilizes the inert gas generated during the carbonisation process (conversion to coke) and hence does not require external inert gas supply unless very low cost inert gas is readily available in the plant site. This provision gives more flexibility to the coke cooling operation thereby making it more adoptable to the economically available inert gas at the site.
It is yet another object of the invention to provide a method for cooling coke wherein the heat exchanged with air can be utilized as pre-heated combustion air in the coke ovens, thereby making the coke oven operation more productive, and take less cycle time. Depending upon the requirement, at site, the hot air could be utilized in the nearby steel plant works for suitable heat supply systems.
The present invention relates to a method of cooling coke wherein the moisture content of the final coke is reduced to 2-3% thereby enhancing the value of the resulting coke. The reduction of moisture content can be explained by the fact that during the first stage of wet quenching process, the optimal quantity of water is sprayed onto coke by way of jets at a specified pressure and time, to rapidly cool

it to a specific temperature, such that only evaporative cooling can take place, preventing additional moisture from entering into the coke. In the second stage of coke dry quenching process, coke produced from the coke oven battery is subject to slow cooling by an inert gas. Thus by the use of optimal quantity of water prior to dry cooling with inert gas, the process ensures low moisture content in the resultant coke.
Accordingly, this invention explains a method for cooling incandescent metallurgical coke using a heat recovery system comprising:
(a) a first stage cooling done using water and inert gas;
(b) a second stage cooling done using inert gas and
(c) a third stage cooling by circulating or ambient air
where the said coke is produced from specific blends of coking coal in coke oven batteries which is pushed into a hot coke car and then moved into a cooling chamber prior to transport and use that is characterized in that the said operation is done through simple coordinated controls which are adjusted based on coal blends used for varying coke bulk density and using minimal supply of inert gas generated during the carbonisation process.
The heat recovery system includes a waste heat boiler (WHB) with a blower and heat exchanger. Excess gas after heat recovery is recycled and used and /or released through the chimney of the heat recovery system. To ensure the flow of inert gas to and from the heat recovery system, the said system includes interconnecting inert gas piping (with or without the refractory brick lining) with valves. The heat recovery system is maintained under suitable pressure either by operating the blower along with the waste heat boiler or by providing a compressor separately in the line or by providing a negative suction at the chimney. In case WHB is not required in the system or cannot be provided for any reason, a heat exchanger to reduce the temperature of coke can be envisaged along with auxiliaries like piping, valves and Instrumentation etc.

In the said first stage of quenching, the optimal quantity of water is sprayed onto coke by way of jets at a specified pressure and for specific time period, to rapidly cool the coke to a specific temperature for evaporative cooling, thus preventing moisture from entering inside the coke. In the second stage the coke is subjected to slow cooling by an inert gas.
Prior to cooling, the hot coke is collected in a hot coke car from coke oven batteries, which is then transported to the Ecocoke Hybrid Quenching (EHQ) station. The hot coke car moves alongside the coke oven batteries and then tilts towards a coke wharf to drop the hot coke into the EHQ station where the said method assists in breaking coke into lumps and reducing the bulk density of hot coke. The hot coke falls on coke wharf and slides into the EHQ first enclosure to perform the first stage of cooling using water and inert gas. A front gate of first EHQ enclosure is opened through a lifting mechanism and the said first enclosure has grates at the bottom and has metallic coverings. Hot coke car collects the coke and drops the coke in the EHQ station repeatedly at specified intervals till the whole hot coke is completely inside the first enclosure. Once the coke is completely inside the first enclosure the front gate is closed and the chamber is sealed. Pressurized water in pulses is sprayed from the top of the first enclosure for a certain period of time such that only partial quenching is achieved with evaporative cooling. Steam generated along with coke dust when water is sprayed on the hot coke, is collected and recycled back into the heat recovery system where the heat is extracted through a tap at the appropriate location in the coke oven battery's common flue passages and the hot flue gas is directed to a waste heat boiler through suction provided by a blower or a suitable compressor. The steam can also be collected and connected to existing steam lines if pressure of the existing system matches and demand for steam exists in the steel plant.
The cold inert gas at specified parameters like temperature and moisture content is introduced from the bottom of the first enclosure grating / mesh where the inert gas flows through the coke mass in an updraft fashion, exchanging heat with hot coke and exits as hot gas at the top of the first enclosure. The hot inert gas at the

top of the first enclosure is collected above the first enclosure from where the said gas is directed to enter the Heat Recovery System by opening the entry valve. After completing the introduction of inert gas for a specified period and collecting the hot gas from the top of the first enclosure in the first stage of the cooling process the partially cooled coke is made available for the second stage of cooling. After completion of the first stage, the back gate is opened and the partially cooled coke is moved from the said first enclosure to a second enclosure to perform the second stage of cooling using inert gas and air where after the said movement the first enclosure is ready to receive more hot coke from coke ovens. The cold inert gas is introduced from the bottom gate of second enclosure to further cool the partially cooled coke and the hot inert gas at the top of the second enclosure is collected above at the said second enclosure where the said gas is allowed to enter the Heat Recovery System by opening the entry valve. The cooled coke from the second enclosure after a specified time is released to open atmosphere for air cooling by opening the second enclosure back gate where the said air cooling in open air or using industrial fan is carried out for a specific time till the coke achieves the required temperature. After air cooled coke reaches the required temperature, the final gate is opened and the coke slides down, where the smallest particles are extracted from the coke breeze screen and dropped into a vibratory conveyor and transported to a coke breeze storage area. Higher size nut coke is extracted from the nut coke screen and dropped into a vibratory conveyor and transported to nut coke storage area. The resulting large size coke from the heat recovery system is dropped into the vibratory conveyor and transported to the large size coke storage area. The said inert gas used is available externally at the site of the said process location or it is a cooled flue gas generated in the coke oven battery during the process of conversion to coke or a suitable combination of both. The heat exchanged with air is utilized as preheated combustion air in the coke ovens and utilized in improving the process time cycle.

These and other objects, features and advantages of the present invention will become more readily apparent from the detailed description taken in conjunction with the drawings and the claims.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS :
Figure 1 illustrates a Non-recovery coke oven battery along with heat recovery system wherein the coke is collected from the oven by pushing onto a moving car.
Figure 2 illustrates a heat recovery system wherein the coke is moved in car and the coke car is tilted towards an inclined wharf.
Figure 3 illustrates a heat recovery system wherein the car drops the hot coke which slides into enclosure 1 for cooling. This is done by opening the front slide gate for the first enclosure.
Figure 4 illustrates a heat recovery system wherein the enclosure 1 is closed and cooling process starts.
Figure 5 illustrates a heat recovery system wherein the water is sprayed to cool the hot coke in enclosure 1.
Figure 6 illustrates a heat recovery system wherein the steam is extracted separately and system extracts heat through a tap at the appropriate location in the coke oven battery's common flue passages and the hot flue gas directed to a waste heat boiler through suction provided by a blower or by a suitable compressor or both.
Figure 7 illustrates a heat recovery system wherein after steam generation is completed the Enclosure #1 suction (through waste heat boiler blower) is closed for the further processing.

Figure 8 illustrates a heat recovery system wherein the inert flue gas or the inert gas or a suitable mixture of both with predetermined moisture content and pressure is introduced in the enclosure 1 to cool the coke.
Figure 9 illustrates a heat recovery system wherein the gas after cooling coke is allowed to pass to the system from the enclosure 1. The coke car is shown to return to the ovens.
Figure 10 illustrates a heat recovery system wherein the hot inert gas is passed to the boiler and excess gas will be released through the chimney.
Figure 11 illustrates a heat recovery system wherein the coke is sent in enclosure 2 for further cooling.
Figure 12 illustrates a heat recovery system wherein the cold inert flue gas or the inert gas or a suitable mixture of both with predetermined moisture content and pressure is introduced for further cooling in enclosure 2.
Figure 13 illustrates a heat recovery system wherein coke from enclosure wherein partially cooled coke is further pushed to get cooled in the open air or by circulating air through industrial fan and enclosure 1 is opened for further action depending upon the process cycle time.
Figure 14 illustrates a heat recovery system wherein the coke further slides on to vibratory screens.
Figure 15 illustrates a heat recovery system wherein the coke is collected after screening in storage. Simultaneously, the coke is introduced into enclosure 1 depending upon the cycle time.

Figure 16 illustrates a heat recovery system where the cooled coke is taken out for transport and the coke from the oven push car moves towards enclosure 1 (depends on cycle time)
Figure 17 illustrates a heat recovery system wherein coke after cooling in enclosure 1 slides to enclosure 2 for further cooling (depends on cycle time)
Figure 18 illustrates a heat recovery system wherein the back gate of enclosure 2 is opened and coke slides down for filtration.
Figure 19 illustrates a heat recovery system wherein the cooled coke is settled in the chambers according to its size.
Figure 20 illustrates a heat recovery system wherein the process repeats itself.
Figure 21 illustrates a heat recovery system where boilers are replaced by heat exchangers in specific cases.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description and drawings are not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail.

Figure 1 shows a heat recovery system, which consists of a waste heat boiler (1) with a blower (2), heat exchanger / (s) (3), compressor wherever required, water injection onto the inert gas wherever required, three stages of coke cooling section where the first stage of cooling is effected using water and inert gas (4) and the second stage by using inert gas and a third stage of cooling only by circulating air or by ambient air (5). It also comprises of a coke screening section which consists of breeze coke screen to collect the coke of smallest size (6) and nut coke screen to collect coke of next size (7). The resulting large size coke (blast furnace grade, etc.) is finally dropped into the conveyor and transported to the large size coke storage area. The system consists of a chimney (9) to release the excess gas after heat recovery. It also provides interconnecting inert gas piping with valves, to ensure the flow of inert gas to and from the heat recovery system. Here the hot coke from coke oven batteries having temperature as high as 1100° C collected in a hot coke car which is then ready to be transported (from a single oven at a time) to the Eco-Coke Hybrid Quenching (EHQ) station. The heat exchanger / (s) acts as air pre-heater for heating the air used in coke ovens, thereby improving the process.
Referring to Figure 2 the hot coke car moves alongside the coke oven batteries and then tilts (or aligns with a pusher mechanism) towards the coke wharf to drop the hot coke into the EHQ station. This assists in breaking coke into lumps and reducing the bulk density of hot coke.
Referring to Figure 3 the hot coke falls on coke wharf and gradually (due to gravity) slides into the EHQ enclosure one to perform the first stage of cooling using water and inert gas. The front gate of EHQ enclosure one is opened through a lifting mechanism. The enclosure has gates at the bottom and metallic coverings or refractory lined metallic covers, wherever required).
Referring to Figure 4 the hot coke car goes back again to collect the coke and drop in the EHQ station at specified intervals. Once the hot coke is completely inside the enclosure one, the front gate is closed sealing the chamber.

Referring to Figure 5 , Pressurized water in pulses is sprayed from the top of the coke in the Enclosure one for a certain period of time such that only partial quenching is achieved with evaporative cooling and moisture does not get enough time to enter inside coke, which ensures higher quality of coke.
Referring to Figure 6 after water spray on the hot coke, steam with coke dust is generated and steam is collected separately or sent to heat recovery system. The heat recovery system that exists in the specific plant extracts heat through a tap at the appropriate location in the coke oven battery's common flue passages and the hot flue gas directed to a waste heat boiler through suction provided by a blower or a suitable compressor.
Referring to Figure 7 and Figure 8 the inert gas at suitable temperatures and predetermined moisture content is introduced from the bottom of the Enclosure one grating / mesh. The inert gas moves through the coke mass in an updraft fashion, exchanging heat with hot coke and exits as hot gas at the top of the enclosure one.
Referring to Figure 9 the hot inert gas at the top of the Enclosure one is collected through the piping above the enclosure.
Referring to Figure 10, the hot inert gas collected in the piping above Enclosure one is allowed to enter the Heat Recovery System by opening the entry valve.
Referring to Figure 11, after introducing of inert gas for a specified period and collecting the hot gas from top of the enclosure the cooling process in Enclosure one is completed. Now the partially cooled coke slides down to enclosure 2.
Referring to Figure 12 wherein after completion of the first phase the back gates will be opened and the partially cooled coke will be moved from Enclosure one to Enclosure two.

Referring to Figure 13 partially cooled coke is now completely out of the enclosure two and it slides down in the open air giving it space for more cooling. Now Enclosure one is ready to receive more hot coke from coke ovens.
Referring to Figure 14, the coke further slides down to screening .
Referring to Figure 15, the hot inert gas collected in the piping above Enclosure one/ two is allowed to enter the Heat Recovery System by opening the entry valve depending upon the cycle time.
Referring to Figure 16, Coke enters enclosure 1 for cooling Enclosure one wet quenching process is repeated as explained in earlier steps..
Referring to Figure 17, coke enters enclosure 2 for further cooling Referring to Figure 18, after air cooled coke reaches 50degC temperature, the final gate is opened and coke slides down, while sliding down, the smallest particles (called coke breeze) are extracted from the coke breeze screen and dropped into a vibratory conveyor and transported to coke breeze storage area. The next higher size of coke (nut coke) is extracted from the nut coke screen and dropped into a vibratory conveyor and transported to nut coke storage area.
Referring to Figure 19, the resulting large size coke (blast furnace grade, etc.) is finally dropped into the vibratory conveyor and transported to the large size coke storage area.
After completing the above, the process repeats as shown in Figure 20
Figure 21 illustrates a process where the heat exchangers are used instead of heat recovery boilers in specific cases.

The hot coke car with the hot coke (from a single oven at a time) moves alongside the coke oven batteries and then tilts (or aligns with a pusher mechanism) that drops the hot coke into an inclined surface (called wharf). This assists in breaking coke into lumps and reducing the bulk density of hot coke. The hot coke rolls down the inclined wharf and enters an enclosure with grates at the bottom and metallic covers (refractory lined wherever required). After the hot coke is
completely inside the enclosure, the gate in front of the enclosure closes and
*
seals the area surrounding the hot coke. Water is then sprayed onto coke by way of jets at a specified pressure and time to rapidly cool it to a specific temperature such that only evaporative cooling can take place preventing moisture from entering inside the coke. The steam produced during this process is recycled back into the heat recovery system or collected separately. After the partial wet quenching operation is complete, the water sprays are turned off and inert gas at ambient temperatures is introduced from the bottom of the grates. The inert gas moves through the coke mass in an updraft fashion and exits as hot gas from the top of the enclosure. The hot inert gas along with fine coke dust from top of the enclosure is recycled back into the heat recovery system.
Source of Inert Gas & Heat Recovery System
Source of inert gas can be external such as low cost nitrogen that may be available at site for other purposes or it can be cooled flue gas generated in the coke oven battery during the process of carbonization (conversion to coke) or a combination of both depending upon economics and availability.
A heat recovery system may exist in specific plants. This system would extract heat through a tap at the appropriate location in the coke oven battery's common flue passages and the hot flue gas directed to a waste heat boiler through suction provided by a blower.
In case, a heat recovery system does not exist in the specific plant, a gas cooler / air pre-heater type heat exchanger can be installed in place of the waste heat

boiler as described above. The function of this heat exchanger would be to cool the hot flue gas.
In the case that the preferred source of inert gas is cooled coke oven battery flue gas, instead of venting the cooled flue gas, heat is extracted in the form of steam in the waste heat boiler, a portion of this gas is passed through a heat exchanger where the flue gas temperature is reduced to 100 deg C. This cooled flue gas is inert in nature but may contain over 7% oxygen. A small quantity of inert gas rich in un-burnt hydrocarbons can be extracted from a specific location in the coke oven battery's common flue tunnel and introduced into this inert gas line to combust with the available oxygen to reduce oxygen in the line to less than 1 %. This inert gas (with less than 1% oxygen) is introduced into the enclosure through a grating below as described above for dry cooling of hot coke. The air that exchanged heat with the inert gas can then be introduced into the coke ovens as pre-heated combustion air further enhancing its productivity while conserving energy. The system described above is the heat recovery system.
All necessary automatic controls and measuring instruments like pressure controllers, temperature controllers, timers, control valves, pressure, flow and temperature indicators, etc are considered.
The foregoing description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention.

Thus, while the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of embodiments of the invention will be employed without a corresponding use of other features without departing from the scope and spirit of the invention as set forth. Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit of the present invention. It is intended that the invention not be limited to the particular terms used in following claims and / or to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include any and all embodiments and equivalents falling within the scope of the appended claims.

WE CLAIM
1. A method for cooling incandescent metallurgical coke using a heat recovery
system comprising:
(a) a first stage cooling done using water and inert gas; and
(b) a second stage cooling done using inert gas; and
(c) a third stage cooling done by circulating or ambient air
where the said coke is produced from specific blends of coking coal in coke oven batteries which is pushed into a hot coke car and then moved into a cooling chamber prior to transport and use characterized in that the said operation is done through simple coordinated controls that is adjusted based on coal blends that are used that results in varying coke bulk density and using minimal supply of inert gas generated during the carbonisation process or available otherwise at site.
2. A method as claimed in claim 1 wherein the heat recovery system, includes a waste heat boiler with a blower and heat exchanger(s) or an equivalent heat exchanger system.
3. A method as claimed in claim 1 wherein in the said first stage the optimal quantity of water is sprayed onto coke by way of jets at a specified pressure and time, to rapidly cool the coke to a specific temperature for evaporative cooling, thus preventing moisture from entering inside the coke.
4. A method as claimed in claim 1 wherein in the second stage the coke produced is given slow cooling by an inert gas.
5. A method as claimed in claim 1 wherein the hot coke fall on coke wharf and slides into the first enclosure to perform the first stage of cooling using water and inert gas.

6. A method as claimed in claim 1 wherein a front gate of first enclosure is opened through a lifting mechanism and the said first enclosure has gates at the bottom and has metallic coverings.
7. A method as claimed in claim 1 wherein hot coke car collects the coke and drop the coke in the EHQ station repeatedly at specified intervals till the whole hot coke is completely inside the first enclosure.
8. A method as claimed in claim 1 wherein once the coke is completely inside the first enclosure the front gate is closed and the chamber is sealed.
9. A method as claimed in claim 1 wherein pressurized water in pulses is sprayed from the top of the first enclosure for a certain period of time such that only partial quenching is achieved with evaporative cooling.
10. A method as claimed in claim 1 wherein steam with coke dust generated when water is spray on the hot coke, is collected separately or recycled back into the heat recovery system where the heat is extracted through a tap at the appropriate location in the coke oven battery's common flue passages and the hot flue gas is directed to a waste heat boiler through suction provided by a blower or a suitable compressor in the system.
11. A method as claimed in claim 1 wherein, the known parameters of inert gas with purity, temperature and pressure and flow rate is introduced from the bottom of the first enclosure grating / mesh where the inert gas moves through the coke mass in an updraft fashion, exchanging heat with hot coke and exits as hot gas at the top of the first enclosure.
12. A method as claimed in claim 1 wherein the hot inert gas at the top of the first enclosure is collected on the piping above the first enclosure where the said gas is allowed to enter the Heat Recovery System by opening the entry valve.

13. A method as claimed in claim 1 wherein after completing the introduction of inert gas for a specified period and collecting the hot gas from top of the first enclosure in the first stage of the cooling process the partially cooled coke is made available for the second stage of cooling.
14. A method as claimed in claim 1 wherein after completion of the first stage, the back gate is opened and the partially cooled coke is moved from the said first enclosure to a second enclosure to perform the second stage of cooling using inert gas and air where after the said movement the first enclosure is ready to receive more hot coke from coke ovens.
15. A method as claimed in claim 1 wherein the inert gas of known parameters is introduced from the bottom gate of second enclosure to further cool the partially cooled coke and the hot inert gas at the top of the second enclosure is collected on the piping above the said second enclosure where the said gas is allowed to enter the Heat Recovery System by opening the entry valve.
16. A method as claimed in claim 1 wherein the cooled coke from the second enclosure after a specified time is released to open atmosphere for air cooling by opening the second enclosure back gate where the said third stage of air cooling in open air or using industrial fan is carried out for a specific time till the coke temperature is of the required temperature. The stages of cooling will be determined by the process cycle and cooling time available and accordingly could be increased or decreased.
17. A method as claimed in claim 1 wherein after air cooled coke reaches the required temperature, the final gate is opened and the coke slides down, where the smallest particles are extracted from the coke breeze screen and dropped into a conveyor and transported to a coke breeze storage area.

18. A method as claimed in claim 1 wherein higher size nut coke is extracted from the nut coke screen and dropped into a conveyor and transported to nut coke storage area.
19. A method as claimed in claim 1 wherein the resulting large size coke from the heat recovery system is dropped into the conveyor and transported to the large size coke storage area.
20. A method as claimed in claim 1 wherein the said inert gas used for the said method is available externally at the site of the said process location or it is a cooled flue gas generated in the coke oven battery during the process of conversion to coke or a combination of both.
21. A method as claimed in claim 1 wherein the heat exchanged with air is utilized as pre-heated combustion air in the coke ovens.
22. A method for cooling incandescent metallurgical coke using a heat recovery system herein described particularly with reference to the drawings.